US20190167114A1 - Near-infrared laser diodes used in imaging applications - Google Patents
Near-infrared laser diodes used in imaging applications Download PDFInfo
- Publication number
- US20190167114A1 US20190167114A1 US16/272,069 US201916272069A US2019167114A1 US 20190167114 A1 US20190167114 A1 US 20190167114A1 US 201916272069 A US201916272069 A US 201916272069A US 2019167114 A1 US2019167114 A1 US 2019167114A1
- Authority
- US
- United States
- Prior art keywords
- light emitting
- signal
- optical beam
- receiver
- emitting diode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000003384 imaging method Methods 0.000 title description 3
- 238000005259 measurement Methods 0.000 claims abstract description 80
- 210000000707 wrist Anatomy 0.000 claims abstract description 6
- 230000003287 optical effect Effects 0.000 claims description 88
- 239000008280 blood Substances 0.000 claims description 77
- 210000004369 blood Anatomy 0.000 claims description 77
- 238000000034 method Methods 0.000 claims description 49
- 230000005540 biological transmission Effects 0.000 claims description 27
- 230000003595 spectral effect Effects 0.000 claims description 24
- 238000001514 detection method Methods 0.000 claims description 17
- 230000008569 process Effects 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 3
- 239000000835 fiber Substances 0.000 description 178
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 82
- 239000008103 glucose Substances 0.000 description 82
- 239000000470 constituent Substances 0.000 description 64
- 210000003491 skin Anatomy 0.000 description 51
- 238000010521 absorption reaction Methods 0.000 description 47
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 41
- 238000001228 spectrum Methods 0.000 description 40
- 150000002576 ketones Chemical class 0.000 description 38
- 210000001519 tissue Anatomy 0.000 description 34
- 238000002835 absorbance Methods 0.000 description 22
- 238000012544 monitoring process Methods 0.000 description 21
- 210000003298 dental enamel Anatomy 0.000 description 19
- 239000000463 material Substances 0.000 description 19
- 239000000523 sample Substances 0.000 description 19
- HVYWMOMLDIMFJA-DPAQBDIFSA-N cholesterol Chemical compound C1C=C2C[C@@H](O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@H]([C@H](C)CCCC(C)C)[C@@]1(C)CC2 HVYWMOMLDIMFJA-DPAQBDIFSA-N 0.000 description 18
- 210000004268 dentin Anatomy 0.000 description 18
- 230000008901 benefit Effects 0.000 description 14
- 210000004207 dermis Anatomy 0.000 description 14
- 238000013461 design Methods 0.000 description 14
- 239000006185 dispersion Substances 0.000 description 14
- 229910052691 Erbium Inorganic materials 0.000 description 13
- 102000001554 Hemoglobins Human genes 0.000 description 13
- 108010054147 Hemoglobins Proteins 0.000 description 13
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 13
- 229910052769 Ytterbium Inorganic materials 0.000 description 12
- 238000000701 chemical imaging Methods 0.000 description 12
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 12
- 210000003462 vein Anatomy 0.000 description 11
- 206010012601 diabetes mellitus Diseases 0.000 description 10
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 10
- 210000000282 nail Anatomy 0.000 description 10
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 9
- 238000004891 communication Methods 0.000 description 9
- 210000004905 finger nail Anatomy 0.000 description 9
- 230000003902 lesion Effects 0.000 description 9
- 238000004611 spectroscopical analysis Methods 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 102000008186 Collagen Human genes 0.000 description 8
- 108010035532 Collagen Proteins 0.000 description 8
- 102000016942 Elastin Human genes 0.000 description 8
- 108010014258 Elastin Proteins 0.000 description 8
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 8
- 229920001436 collagen Polymers 0.000 description 8
- DDRJAANPRJIHGJ-UHFFFAOYSA-N creatinine Chemical compound CN1CC(=O)NC1=N DDRJAANPRJIHGJ-UHFFFAOYSA-N 0.000 description 8
- 229920002549 elastin Polymers 0.000 description 8
- 230000010287 polarization Effects 0.000 description 8
- 150000003626 triacylglycerols Chemical class 0.000 description 8
- 239000004202 carbamide Substances 0.000 description 7
- 235000012000 cholesterol Nutrition 0.000 description 7
- 201000010099 disease Diseases 0.000 description 7
- 230000002452 interceptive effect Effects 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 230000001360 synchronised effect Effects 0.000 description 7
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 6
- WHBMMWSBFZVSSR-UHFFFAOYSA-N R3HBA Natural products CC(O)CC(O)=O WHBMMWSBFZVSSR-UHFFFAOYSA-N 0.000 description 6
- 206010046996 Varicose vein Diseases 0.000 description 6
- KXNLCSXBJCPWGL-UHFFFAOYSA-N [Ga].[As].[In] Chemical compound [Ga].[As].[In] KXNLCSXBJCPWGL-UHFFFAOYSA-N 0.000 description 6
- 206010002026 amyotrophic lateral sclerosis Diseases 0.000 description 6
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 6
- 230000008878 coupling Effects 0.000 description 6
- 238000010168 coupling process Methods 0.000 description 6
- 238000005859 coupling reaction Methods 0.000 description 6
- 230000036541 health Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 230000002829 reductive effect Effects 0.000 description 6
- 238000001069 Raman spectroscopy Methods 0.000 description 5
- 230000000712 assembly Effects 0.000 description 5
- 238000000429 assembly Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 230000006870 function Effects 0.000 description 5
- 239000005350 fused silica glass Substances 0.000 description 5
- 238000005286 illumination Methods 0.000 description 5
- 239000004038 photonic crystal Substances 0.000 description 5
- 235000018102 proteins Nutrition 0.000 description 5
- 102000004169 proteins and genes Human genes 0.000 description 5
- 108090000623 proteins and genes Proteins 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 4
- 108010088751 Albumins Proteins 0.000 description 4
- 102000009027 Albumins Human genes 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 229910000661 Mercury cadmium telluride Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 229910052775 Thulium Inorganic materials 0.000 description 4
- 238000000862 absorption spectrum Methods 0.000 description 4
- 230000017531 blood circulation Effects 0.000 description 4
- 210000004204 blood vessel Anatomy 0.000 description 4
- 150000004770 chalcogenides Chemical class 0.000 description 4
- 238000005253 cladding Methods 0.000 description 4
- 229940109239 creatinine Drugs 0.000 description 4
- 210000003074 dental pulp Anatomy 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 235000014113 dietary fatty acids Nutrition 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 210000002615 epidermis Anatomy 0.000 description 4
- 239000003925 fat Substances 0.000 description 4
- 239000000194 fatty acid Substances 0.000 description 4
- 229930195729 fatty acid Natural products 0.000 description 4
- 150000004665 fatty acids Chemical class 0.000 description 4
- 230000004153 glucose metabolism Effects 0.000 description 4
- 210000003128 head Anatomy 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 230000001771 impaired effect Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 239000013307 optical fiber Substances 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 238000004497 NIR spectroscopy Methods 0.000 description 3
- 239000005371 ZBLAN Substances 0.000 description 3
- 230000003321 amplification Effects 0.000 description 3
- 238000013459 approach Methods 0.000 description 3
- 210000001367 artery Anatomy 0.000 description 3
- 238000005452 bending Methods 0.000 description 3
- 210000004556 brain Anatomy 0.000 description 3
- 210000004027 cell Anatomy 0.000 description 3
- 230000015271 coagulation Effects 0.000 description 3
- 238000005345 coagulation Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 208000035475 disorder Diseases 0.000 description 3
- 210000003811 finger Anatomy 0.000 description 3
- 150000002222 fluorine compounds Chemical class 0.000 description 3
- 230000000670 limiting effect Effects 0.000 description 3
- 238000004476 mid-IR spectroscopy Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 238000002310 reflectometry Methods 0.000 description 3
- 210000001525 retina Anatomy 0.000 description 3
- WDJHALXBUFZDSR-UHFFFAOYSA-N Acetoacetic acid Natural products CC(=O)CC(O)=O WDJHALXBUFZDSR-UHFFFAOYSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 102000017011 Glycated Hemoglobin A Human genes 0.000 description 2
- 102000011782 Keratins Human genes 0.000 description 2
- 108010076876 Keratins Proteins 0.000 description 2
- 208000007976 Ketosis Diseases 0.000 description 2
- 241001408665 Timandra griseata Species 0.000 description 2
- LEHOTFFKMJEONL-UHFFFAOYSA-N Uric Acid Chemical compound N1C(=O)NC(=O)C2=C1NC(=O)N2 LEHOTFFKMJEONL-UHFFFAOYSA-N 0.000 description 2
- TVWHNULVHGKJHS-UHFFFAOYSA-N Uric acid Natural products N1C(=O)NC(=O)C2NC(=O)NC21 TVWHNULVHGKJHS-UHFFFAOYSA-N 0.000 description 2
- 238000004847 absorption spectroscopy Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- MCMSPRNYOJJPIZ-UHFFFAOYSA-N cadmium;mercury;tellurium Chemical compound [Cd]=[Te]=[Hg] MCMSPRNYOJJPIZ-UHFFFAOYSA-N 0.000 description 2
- 150000001720 carbohydrates Chemical class 0.000 description 2
- 235000014633 carbohydrates Nutrition 0.000 description 2
- 230000001413 cellular effect Effects 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 2
- 239000012809 cooling fluid Substances 0.000 description 2
- 210000004087 cornea Anatomy 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 208000002925 dental caries Diseases 0.000 description 2
- WOWBFOBYOAGEEA-UHFFFAOYSA-N diafenthiuron Chemical compound CC(C)C1=C(NC(=S)NC(C)(C)C)C(C(C)C)=CC(OC=2C=CC=CC=2)=C1 WOWBFOBYOAGEEA-UHFFFAOYSA-N 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 210000000624 ear auricle Anatomy 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- -1 ketone 3-hydroxybutyrate Chemical class 0.000 description 2
- 238000012417 linear regression Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 210000004185 liver Anatomy 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 238000012628 principal component regression Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000001055 reflectance spectroscopy Methods 0.000 description 2
- 238000000985 reflectance spectrum Methods 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 238000007920 subcutaneous administration Methods 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- SITVSCPRJNYAGV-UHFFFAOYSA-L tellurite Chemical compound [O-][Te]([O-])=O SITVSCPRJNYAGV-UHFFFAOYSA-L 0.000 description 2
- 230000002123 temporal effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- FRNOGLGSGLTDKL-UHFFFAOYSA-N thulium atom Chemical compound [Tm] FRNOGLGSGLTDKL-UHFFFAOYSA-N 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000000844 transformation Methods 0.000 description 2
- 238000002235 transmission spectroscopy Methods 0.000 description 2
- URAYPUMNDPQOKB-UHFFFAOYSA-N triacetin Chemical compound CC(=O)OCC(OC(C)=O)COC(C)=O URAYPUMNDPQOKB-UHFFFAOYSA-N 0.000 description 2
- UFTFJSFQGQCHQW-UHFFFAOYSA-N triformin Chemical compound O=COCC(OC=O)COC=O UFTFJSFQGQCHQW-UHFFFAOYSA-N 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 229940116269 uric acid Drugs 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- WHBMMWSBFZVSSR-UHFFFAOYSA-M 3-hydroxybutyrate Chemical compound CC(O)CC([O-])=O WHBMMWSBFZVSSR-UHFFFAOYSA-M 0.000 description 1
- 208000024827 Alzheimer disease Diseases 0.000 description 1
- 230000005457 Black-body radiation Effects 0.000 description 1
- 102000004506 Blood Proteins Human genes 0.000 description 1
- 108010017384 Blood Proteins Proteins 0.000 description 1
- 241000282465 Canis Species 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- LKDRXBCSQODPBY-VRPWFDPXSA-N D-fructopyranose Chemical compound OCC1(O)OC[C@@H](O)[C@@H](O)[C@@H]1O LKDRXBCSQODPBY-VRPWFDPXSA-N 0.000 description 1
- 235000009161 Espostoa lanata Nutrition 0.000 description 1
- 240000001624 Espostoa lanata Species 0.000 description 1
- 108010014663 Glycated Hemoglobin A Proteins 0.000 description 1
- 208000023105 Huntington disease Diseases 0.000 description 1
- 208000013016 Hypoglycemia Diseases 0.000 description 1
- 206010023379 Ketoacidosis Diseases 0.000 description 1
- QNAYBMKLOCPYGJ-REOHCLBHSA-N L-alanine Chemical compound C[C@H](N)C(O)=O QNAYBMKLOCPYGJ-REOHCLBHSA-N 0.000 description 1
- JVTAAEKCZFNVCJ-UHFFFAOYSA-M Lactate Chemical compound CC(O)C([O-])=O JVTAAEKCZFNVCJ-UHFFFAOYSA-M 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 208000008589 Obesity Diseases 0.000 description 1
- 208000018737 Parkinson disease Diseases 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 210000000577 adipose tissue Anatomy 0.000 description 1
- 238000001042 affinity chromatography Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 235000004279 alanine Nutrition 0.000 description 1
- 230000002547 anomalous effect Effects 0.000 description 1
- 210000002159 anterior chamber Anatomy 0.000 description 1
- 210000001742 aqueous humor Anatomy 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 229940072107 ascorbate Drugs 0.000 description 1
- 235000010323 ascorbic acid Nutrition 0.000 description 1
- 239000011668 ascorbic acid Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 210000004763 bicuspid Anatomy 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- ZADPBFCGQRWHPN-UHFFFAOYSA-N boronic acid Chemical compound OBO ZADPBFCGQRWHPN-UHFFFAOYSA-N 0.000 description 1
- 210000000481 breast Anatomy 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 210000001736 capillary Anatomy 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 230000008727 cellular glucose uptake Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 239000003962 counterfeit drug Substances 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000249 desinfective effect Effects 0.000 description 1
- 235000015872 dietary supplement Nutrition 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 206010015037 epilepsy Diseases 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 231100000040 eye damage Toxicity 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 235000021149 fatty food Nutrition 0.000 description 1
- 102000034240 fibrous proteins Human genes 0.000 description 1
- 108091005899 fibrous proteins Proteins 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium oxide Inorganic materials O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 1
- 208000018914 glucose metabolism disease Diseases 0.000 description 1
- 125000002791 glucosyl group Chemical group C1([C@H](O)[C@@H](O)[C@H](O)[C@H](O1)CO)* 0.000 description 1
- 108091005995 glycated hemoglobin Proteins 0.000 description 1
- 239000001087 glyceryl triacetate Substances 0.000 description 1
- 235000013773 glyceryl triacetate Nutrition 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 210000003780 hair follicle Anatomy 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 210000004247 hand Anatomy 0.000 description 1
- 230000035861 hyperketonemia Effects 0.000 description 1
- 239000002117 illicit drug Substances 0.000 description 1
- 238000003018 immunoassay Methods 0.000 description 1
- 210000004283 incisor Anatomy 0.000 description 1
- 208000015181 infectious disease Diseases 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 235000020887 ketogenic diet Nutrition 0.000 description 1
- 230000004140 ketosis Effects 0.000 description 1
- 150000002632 lipids Chemical class 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 238000007726 management method Methods 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 238000012067 mathematical method Methods 0.000 description 1
- 235000012054 meals Nutrition 0.000 description 1
- 238000013160 medical therapy Methods 0.000 description 1
- 230000004060 metabolic process Effects 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 210000005036 nerve Anatomy 0.000 description 1
- 230000001537 neural effect Effects 0.000 description 1
- 150000002826 nitrites Chemical class 0.000 description 1
- 230000009022 nonlinear effect Effects 0.000 description 1
- 235000016709 nutrition Nutrition 0.000 description 1
- 235000020824 obesity Nutrition 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000003204 osmotic effect Effects 0.000 description 1
- PVADDRMAFCOOPC-UHFFFAOYSA-N oxogermanium Chemical compound [Ge]=O PVADDRMAFCOOPC-UHFFFAOYSA-N 0.000 description 1
- 238000010238 partial least squares regression Methods 0.000 description 1
- 230000037361 pathway Effects 0.000 description 1
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical group [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 description 1
- 230000010412 perfusion Effects 0.000 description 1
- 239000006223 plastic coating Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000013341 scale-up Methods 0.000 description 1
- 210000001732 sebaceous gland Anatomy 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 210000004003 subcutaneous fat Anatomy 0.000 description 1
- 125000001424 substituent group Chemical group 0.000 description 1
- 238000004416 surface enhanced Raman spectroscopy Methods 0.000 description 1
- 210000000106 sweat gland Anatomy 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
- 230000001225 therapeutic effect Effects 0.000 description 1
- 210000003813 thumb Anatomy 0.000 description 1
- 210000005182 tip of the tongue Anatomy 0.000 description 1
- 229960002622 triacetin Drugs 0.000 description 1
- 208000027185 varicose disease Diseases 0.000 description 1
- 238000007879 vasectomy Methods 0.000 description 1
- 238000002460 vibrational spectroscopy Methods 0.000 description 1
Images
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
- A61B5/0088—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for oral or dental tissue
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
- A61B5/0004—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network characterised by the type of physiological signal transmitted
- A61B5/0013—Medical image data
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0002—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network
- A61B5/0015—Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network characterised by features of the telemetry system
- A61B5/0022—Monitoring a patient using a global network, e.g. telephone networks, internet
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0075—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
- A61B5/0082—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
- A61B5/0084—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
- A61B5/0086—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters using infrared radiation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/14532—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring glucose, e.g. by tissue impedance measurement
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/14546—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue for measuring analytes not otherwise provided for, e.g. ions, cytochromes
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
- A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
- A61B5/4538—Evaluating a particular part of the muscoloskeletal system or a particular medical condition
- A61B5/4542—Evaluating the mouth, e.g. the jaw
- A61B5/4547—Evaluating teeth
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7253—Details of waveform analysis characterised by using transforms
- A61B5/7257—Details of waveform analysis characterised by using transforms using Fourier transforms
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/74—Details of notification to user or communication with user or patient ; user input means
- A61B5/7405—Details of notification to user or communication with user or patient ; user input means using sound
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/74—Details of notification to user or communication with user or patient ; user input means
- A61B5/742—Details of notification to user or communication with user or patient ; user input means using visual displays
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0218—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using optical fibers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
- G01J3/108—Arrangements of light sources specially adapted for spectrometry or colorimetry for measurement in the infrared range
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
- G01J3/14—Generating the spectrum; Monochromators using refracting elements, e.g. prisms
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/2823—Imaging spectrometer
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/45—Interferometric spectrometry
- G01J3/453—Interferometric spectrometry by correlation of the amplitudes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3563—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing solids; Preparation of samples therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/359—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using near infrared light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/02—Food
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/02—Food
- G01N33/025—Fruits or vegetables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/15—Medicinal preparations ; Physical properties thereof, e.g. dissolubility
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/44—Resins; Plastics; Rubber; Leather
- G01N33/442—Resins; Plastics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/483—Physical analysis of biological material
- G01N33/487—Physical analysis of biological material of liquid biological material
- G01N33/49—Blood
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G16H40/00—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices
- G16H40/60—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices
- G16H40/67—ICT specially adapted for the management or administration of healthcare resources or facilities; ICT specially adapted for the management or operation of medical equipment or devices for the operation of medical equipment or devices for remote operation
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16Z—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS, NOT OTHERWISE PROVIDED FOR
- G16Z99/00—Subject matter not provided for in other main groups of this subclass
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0233—Special features of optical sensors or probes classified in A61B5/00
- A61B2562/0238—Optical sensor arrangements for performing transmission measurements on body tissue
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/14—Coupling media or elements to improve sensor contact with skin or tissue
- A61B2562/146—Coupling media or elements to improve sensor contact with skin or tissue for optical coupling
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2576/00—Medical imaging apparatus involving image processing or analysis
- A61B2576/02—Medical imaging apparatus involving image processing or analysis specially adapted for a particular organ or body part
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
- G01J2003/102—Plural sources
- G01J2003/104—Monochromatic plural sources
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
- G01J2003/1208—Prism and grating
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/2823—Imaging spectrometer
- G01J2003/2826—Multispectral imaging, e.g. filter imaging
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
- G01J3/18—Generating the spectrum; Monochromators using diffraction elements, e.g. grating
- G01J3/1838—Holographic gratings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/38—Investigating fluid-tightness of structures by using light
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N2021/3595—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using FTIR
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers
- G01N2021/396—Type of laser source
- G01N2021/399—Diode laser
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/9508—Capsules; Tablets
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/02—Mechanical
- G01N2201/022—Casings
- G01N2201/0221—Portable; cableless; compact; hand-held
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
- G01N2201/06113—Coherent sources; lasers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/062—LED's
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/08—Optical fibres; light guides
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/12—Circuits of general importance; Signal processing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/12—Circuits of general importance; Signal processing
- G01N2201/129—Using chemometrical methods
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0092—Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
- H01S3/06758—Tandem amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Definitions
- non-invasive glucose monitoring e.g., monitoring glucose without drawing blood.
- the challenge has been that a non-invasive system requires adequate sensitivity and selectivity, along with repeatability of the results. Yet, this is a very large market, with an estimated annual market of over $10B in 2011 for self-monitoring of glucose levels.
- near-infrared spectroscopy such as absorption spectroscopy or near-infrared diffuse reflection or transmission spectroscopy.
- broadband light sources such as tungsten lamps
- spectroscopy and pattern matching often called spectral fingerprinting
- the non-invasive procedures have often transmitted or reflected light through the skin, but skin has many spectral artifacts in the near-infrared that may mask the glucose signatures.
- the skin may have significant water and blood content.
- the near-infrared signal level from blood constituents may be increased.
- the teeth which have fewer spectral artifacts than skin in the near-infrared
- the blood constituents may be measured with less interfering artifacts.
- pattern matching in spectral fingerprinting and various software techniques the signatures from different constituents in the blood may be identified.
- value-add services may be provided by wirelessly communicating the monitored data to a handheld device such as a smart phone, and then wirelessly communicating the processed data to the cloud for storing, processing, and transmitting to several locations.
- a smart phone or tablet comprises one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue.
- An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue.
- An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, wherein the infrared camera generates data based at least in part on the received light.
- the infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, and wherein the infrared camera generates additional data based at least in part on the received light.
- the infrared camera is further configured to: receive light while the one or more laser diodes and the array of laser diodes are off and convert the received light into a first signal; and receive light while at least some of the one or more laser diodes or some of the array of laser diodes are on, and convert the received light into a second signal, the received light including at least a part of the portion of the light from the at least one of the one or more laser diodes reflected from the tissue, or at least a part of the portion of the light from the array of laser diodes reflected from the tissue.
- the smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using a difference between the first signal and the second signal, and using at least part of the data or at least part of the additional data from the infrared camera.
- the smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- Embodiments may include a smart phone or tablet comprising one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue.
- An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue.
- An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, and wherein the infrared camera generates data based at least in part on the received light.
- the infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, wherein the infrared camera generates additional data based at least in part on the received light.
- the smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using at least part of the data or part of the additional data from the infrared camera.
- the smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- a smart phone or tablet comprises one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue.
- An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers.
- a second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue, wherein the plurality of spots are also formed at least in part by using an assembly in front of the array of laser diodes.
- An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, wherein the infrared camera generates data based at least in part on the received light.
- the infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, wherein the infrared camera generates additional data based at least in part on the received light.
- the smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using at least part of the data or part of the additional data from the infrared camera.
- the smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- FIG. 1 plots the transmittance versus wavenumber for glucose in the mid-wave and long-wave infrared wavelengths between approximately 2.7 to 12 microns.
- FIG. 2 illustrates measurements of the absorbance of different blood constituents, such as glucose, hemoglobin, and hemoglobin A1c. The measurements are done using an FTIR spectrometer in samples with a 1 mm path length.
- FIG. 3A shows the normalized absorbance of water and glucose (not drawn to scale). Water shows transmission windows between about 1500-1850 nm and 2050-2500 nm.
- FIG. 3B illustrates the absorbance of hemoglobin and oxygenated hemoglobin overlapped with water.
- FIG. 4A shows measured absorbance in different concentrations of glucose solution over the wavelength range of about 2000 to 2400 nm. This data is collected using a SWIR super-continuum laser with the sample path length of about 1.1 mm.
- FIG. 4B illustrates measured absorbance in different concentrations of glucose solution over the wavelength range of about 1550 to 1800 nm.
- the data is collected using a SWIR super-continuum laser with a sample path length of about 10 mm.
- FIG. 5 illustrates the spectrum for different blood constituents in the wavelength range of about 2 to 2.45 microns (2000 to 2450 nm).
- FIG. 6 shows the transmittance versus wavelength in microns for the ketone 3-hydroxybutyrate.
- the wavelength range is approximately 2 to 16 microns.
- FIG. 7 illustrates the optical absorbance for ketones as well as some other blood constituents in the wavelength range of about 2100 to 2400 nm.
- FIG. 8A shows the first derivative spectra of ketone and protein at concentrations of 10 g/L (left). In addition, the first derivative spectra of urea, creatinine, and glucose are shown on the right at concentrations of 10 g/L.
- FIG. 8B illustrates the near infrared absorbance for triglyceride.
- FIG. 8C shows the near-infrared reflectance spectrum for cholesterol.
- FIG. 8D illustrates the near-infrared reflectance versus wavelength for various blood constituents, including cholesterol, glucose, albumin, uric acid, and urea.
- FIG. 9 shows a schematic of the human skin.
- the dermis may comprise significant amounts of collagen, elastin, lipids, and water.
- FIG. 10 illustrates the absorption coefficients for water (including scattering), adipose, collagen, and elastin.
- FIG. 11 shows the dorsal of the hand, where a differential measurement may be made to at least partially compensate for or subtract out the skin interference.
- FIG. 12 shows the dorsal of the foot, where a differential measurement may be made to at least partially compensate for or subtract out the skin interference.
- FIG. 13A shows an embodiment that may comprise multiple collimated or focused light beams.
- FIG. 13B illustrates a typical human nail tissue structure and the capillary vessels below it.
- FIG. 14 shows the attenuation coefficient for seven nail samples that are allowed to stand in an environment with a humidity level of 14%. These coefficients are measured using an FTIR spectrometer over the near-infrared wavelength range of approximately 1 to 2.5 microns. Below is also included the spectrum of glucose.
- FIG. 15 illustrates the structure of a tooth.
- FIG. 16A shows the attenuation coefficient for dental enamel and water versus wavelength from approximately 600 nm to 2600 nm.
- FIG. 16B illustrates the absorption spectrum of intact enamel and dentine in the wavelength range of approximately 1.2 to 2.4 microns.
- FIG. 17 shows the near infrared spectral reflectance over the wavelength range of approximately 800 nm to 2500 nm from an occlusal tooth surface.
- the black diamonds correspond to the reflectance from a sound, intact tooth section.
- the asterisks correspond to a tooth section with an enamel lesion.
- the circles correspond to a tooth section with a dentine lesion.
- FIG. 18A illustrates a clamp design of a human interface to cap over one or more teeth and perform a non-invasive measurement of blood constituents.
- FIG. 18B shows a mouth guard design of a human interface to perform a non-invasive measurement of blood constituents.
- FIG. 19 illustrates a block diagram or building blocks for constructing high power laser diode assemblies.
- FIG. 20 shows a platform architecture for different wavelength ranges for an all-fiber-integrated, high powered, super-continuum light source.
- FIG. 21 illustrates one embodiment of a short-wave infrared (SWIR) super-continuum (SC) light source.
- SWIR short-wave infrared
- SC super-continuum
- FIG. 22 shows the output spectrum from the SWIR SC laser of FIG. 21 when .about.10 m length of fiber for SC generation is used.
- This fiber is a single-mode, non-dispersion shifted fiber that is optimized for operation near 1550 nm.
- FIG. 23 illustrates high power SWIR-SC lasers that may generate light between approximately 1.4-1.8 microns (top) or approximately 2-2.5 microns (bottom).
- FIG. 24 schematically shows that the medical measurement device can be part of a personal or body area network that communicates with another device (e.g., smart phone or tablet) that communicates with the cloud.
- the cloud may in turn communicate information with the user, healthcare providers, or other designated recipients.
- Various ailments or diseases may require measurement of the concentration of one or more blood constituents.
- diabetes may require measurement of the blood glucose and HbA1c levels.
- diseases or disorders characterized by impaired glucose metabolism may require the measurement of ketone bodies in the blood. Examples of impaired glucose metabolism diseases include Alzheimer's, Parkinson's, Huntington's, and Lou Gehrig's or amyotrophic lateral sclerosis (ALS).
- Techniques related to near-infrared spectroscopy or hyper-spectral imaging may be particularly advantageous for non-invasive monitoring of some of these blood constituents.
- Hyper-spectral images may provide spectral information to identify and distinguish between spectrally similar materials, providing the ability to make proper distinctions among materials with only subtle signature differences.
- SWIR wavelength range numerous gases, liquids and solids have unique chemical signatures, particularly materials comprising hydro-carbon bonds, O—H bonds, N—H bonds, etc. Therefore, spectroscopy in the SWIR may be attractive for stand-off or remote sensing of materials based on their chemical signature, which may complement other imaging information.
- Hyper-spectral sensors may collect information as a set of images, where each image represents a range of wavelengths over a spectral band.
- Hyper-spectral imaging may deal with imaging narrow spectral bands over an approximately continuous spectral range.
- the sun may be used as the illumination source, and the daytime illumination may comprise direct solar illumination as well as scattered solar (skylight), which is caused by the presence of the atmosphere.
- the sun illumination changes with time of day, clouds or inclement weather may block the sun light, and the sun light is not accessible in the night time. Therefore, it would be advantageous to have a broadband light source covering the SWIR that may be used in place of the sun to identify or classify materials in remote sensing or stand-off detection applications.
- a SWIR camera or infrared camera system may be used to capture the images.
- the camera may include one or more lenses on the input, which may be adjustable.
- the focal plane assemblies may be made from mercury cadmium telluride material (HgCdTe), and the detectors may also include thermo-electric coolers.
- the image sensors may be made from indium gallium arsenide (InGaAs), and CMOS transistors may be connected to each pixel of the InGaAs photodiode array.
- the camera may interface wirelessly or with a cable (e.g., USB, Ethernet cable, or fiber optics cable) to a computer or tablet or smart phone, where the images may be captured and processed.
- a cable e.g., USB, Ethernet cable, or fiber optics cable
- the fiber-based super-continuum lasers may have a pulsed output with pulse durations of approximately 0.5-2 nsec and pulse repetition rates of several Megahertz. Therefore, the active remote sensing or hyper-spectral imaging applications may also be combined with LIDAR-type applications. Namely, the distance or time axis can be added to the information based on time-of-flight measurements.
- the detection system would also have to be time-gated to be able to measure the time difference between the pulses sent and the pulses received. By calculating the round-trip time for the signal, the distance of the object may be judged.
- GPS global positioning system
- the active remote sensing or hyper-spectral imagery would also have a location tag on the data.
- the active remote sensing or hyper-spectral imaging information could also be combined with two-dimensional or three-dimensional images to provide a physical picture as well as a chemical composition identification of the materials.
- the fiber-based super-continuum lasers may have a pulsed output with pulse durations of approximately 0.5-2 nsec and pulse repetition rates of several Megahertz. Therefore, the active remote sensing or hyper-spectral imaging applications may also be combined with LIDAR-type applications. Namely, the distance or time axis can be added to the information based on time-of-flight measurements.
- the detection system would also have to be time-gated to be able to measure the time difference between the pulses sent and the pulses received. By calculating the round-trip time for the signal, the distance of the object may be judged.
- GPS global positioning system
- the active remote sensing or hyper-spectral imagery would also have a location tag on the data.
- the active remote sensing or hyper-spectral imaging information could also be combined with two-dimensional or three-dimensional images to provide a physical picture as well as a chemical composition identification of the materials.
- a surface cooling apparatus may be used, where a cooling fluid may be flowed either touching or in close proximity to the skin.
- a cylindrical assembly may optionally be used, where the cylindrical length may be several millimeters in length and defined by a clamp or mount placed on or near the leg.
- a window and/or lenslet array is also shown on the cylindrical surface for permitting the light to be incident on the skin and varicose vein at multiple spots.
- the lenslet array may comprise circular, spherical or cylindrical lenses, depending on the type of spots desired.
- one advantage of placing the lenslet array in close proximity to the skin and varicose vein may be that a high NA, lens may be used.
- the input from the lens and/or mirror assembly to the lenslet array may be single large beam, or a plurality of smaller beams.
- a plurality of spots may be created by the lenslet array to cause a plurality of locations of thermal coagulation in the varicose vein. Any number of spots may be used and are intended to be covered by this disclosure.
- a plurality of spots may be used, or what might be called a fractionated beam.
- the fractionated laser beam may be added to the laser delivery assembly or delivery head in a number of ways.
- a screen-like spatial filter may be placed in the pathway of the beam to be delivered to the biological tissue.
- the screen-like spatial filter can have opaque regions to block the light and holes or transparent regions, through which the laser beam may pass to the tissue sample. The ratio of opaque to transparent regions may be varied, depending on the application of the laser.
- a lenslet array can be used at or near the output interface where the light emerges.
- At least a part of the delivery fiber from the infrared laser system to the delivery head may be a bundle of fibers, which may comprise a plurality of fiber cores surrounded by cladding regions.
- the fiber cores can then correspond to the exposed regions, and the cladding areas can approximate the opaque areas not to be exposed to the laser light.
- a bundle of fibers may be excited by at least a part of the laser system output, and then the fiber bundle can be fused together and perhaps pulled down to a desired diameter to expose to the tissue sample near the delivery head.
- a photonic crystal fiber may be used to create the fractionated laser beam.
- the photonic crystal fiber can be coupled to at least a part of the laser system output at one end, and the other end can be coupled to the delivery head.
- the fractionated laser beam may be generated by a heavily multi-mode fiber, where the speckle pattern at the output may create the high intensity and low intensity spatial pattern at the output.
- the output from a fiber laser may be from a single or multi-mode fiber, different spatial spot sizes or spatial profiles may be beneficial for different applications. For example, in some instances it may be desirable to have a series of spots or a fractionated beam with a grid of spots.
- a bundle of fibers or a light pipe with a plurality of guiding cores may be used.
- one or more fiber cores may be followed by a lenslet array to create a plurality of collimated or focused beams.
- a delivery light pipe may be followed by a grid-like structure to divide up the beam into a plurality of spots.
- the term “couple” and or “coupled” refers to any direct or indirect communication between two or more elements, whether or not those elements are physically connected to one another.
- the term “spectroscopy” means that a tissue or sample is inspected by comparing different features, such as wavelength (or frequency), spatial location, transmission, absorption, reflectivity, scattering, refractive index, or opacity.
- “spectroscopy” may mean that the wavelength of the light source is varied, and the transmission, absorption or reflectivity of the tissue or sample is measured as a function of wavelength.
- “spectroscopy” may mean that the wavelength dependence of the transmission, absorption or reflectivity is compared between different spatial locations on a tissue or sample.
- the “spectroscopy” may be performed by varying the wavelength of the light source, or by using a broadband light source and analyzing the signal using a spectrometer, wavemeter, or optical spectrum analyzer.
- the term “fiber laser” refers to a laser or oscillator that has as an output light or an optical beam, wherein at least a part of the laser comprises an optical fiber.
- the fiber in the “fiber laser” may comprise one of or a combination of a single mode fiber, a multi-mode fiber, a mid-infrared fiber, a photonic crystal fiber, a doped fiber, a gain fiber, or, more generally, an approximately cylindrically shaped waveguide or light-pipe.
- the gain fiber may be doped with rare earth material, such as ytterbium, erbium, and/or thulium.
- the mid-infrared fiber may comprise one or a combination of fluoride fiber, ZBLAN fiber, chalcogenide fiber, tellurite fiber, or germanium doped fiber.
- the single mode fiber may include standard single-mode fiber, dispersion shifted fiber, non-zero dispersion shifted fiber, high-nonlinearity fiber, and small core size fibers.
- the term “pump laser” refers to a laser or oscillator that has as an output light or an optical beam, wherein the output light or optical beam is coupled to a gain medium to excite the gain medium, which in turn may amplify another input optical signal or beam.
- the gain medium may be a doped fiber, such as a fiber doped with ytterbium, erbium or thulium.
- the “pump laser” may be a fiber laser, a solid state laser, a laser involving a nonlinear crystal, an optical parametric oscillator, a semiconductor laser, or a plurality of semiconductor lasers that may be multiplexed together.
- the “pump laser” may be coupled to the gain medium by using a fiber coupler, a dichroic mirror, a multiplexer, a wavelength division multiplexer, a grating, or a fused fiber coupler.
- the term “super-continuum” and or “supercontinuum” and or “SC” refers to a broadband light beam or output that comprises a plurality of wavelengths.
- the plurality of wavelengths may be adjacent to one-another, so that the spectrum of the light beam or output appears as a continuous band when measured with a spectrometer.
- the broadband light beam may have a bandwidth of at least 10 nm.
- the “super-continuum” may be generated through nonlinear optical interactions in a medium, such as an optical fiber or nonlinear crystal.
- the “super-continuum” may be generated through one or a combination of nonlinear activities such as four-wave mixing, the Raman effect, modulational instability, and self-phase modulation.
- optical light and or “optical beam” and or “light beam” refer to photons or light transmitted to a particular location in space.
- the “optical light” and or “optical beam” and or “light beam” may be modulated or unmodulated.
- the “optical light” and or “optical beam” and or “light beam” may originate from a fiber, a fiber laser, a laser, a light emitting diode, a lamp, a pump laser, or a light source.
- the “near-infrared (NIR)” region of the electromagnetic spectrum covers between approximately 0.7 microns (700 nm) to about 2.5 microns (2500 nm).
- the glucose molecule has the chemical formula C 6 H 12 O 6 , so it has a number of hydro-carbon bonds.
- An example of the infrared transmittance of glucose 100 is illustrated in FIG. 1 .
- the vibrational spectroscopy shows that the strongest lines for bending and stretching modes of C—H and O—H bonds lie in the wavelength range of approximately 6-12 microns.
- light sources and detectors are more difficult in the mid-wave infrared and long-wave infrared, and there is also strongly increasing water absorption in the human body beyond about 2.5 microns.
- weaker there are also nonlinear combinations of stretching and bending modes between about 2 to 2.5 microns, and first overtone of C—H stretching modes between approximately 1.5-1.8 microns.
- SWIR short-wave infrared
- measurements of the optical absorbance 200 of hemoglobin, glucose and HbA1c have been performed using a Fourier-Transform Infrared Spectrometer—FTIR.
- FTIR Fourier-Transform Infrared Spectrometer
- the glucose absorbance 202 has at least five distinct peaks near 1587 nm, 1750 nm, 2120 nm, 2270 nm and 2320 nm.
- FIG. 3A overlaps 300 the normalized absorbance of glucose 301 with the absorbance of water 302 (not drawn to scale). It may be seen that water has an absorbance feature between approximately 1850 nm and 2050 nm, but water 302 also has a nice transmission window between approximately 1500-1850 nm and 2050 to 2500 nm. For wavelengths less than about 1100 nm, the absorption of hemoglobin 351 and oxygenated hemoglobin 352 in FIG. 3B has a number of features 350 , which may make it more difficult to measure blood constituents. Also, beyond 2500 nm the water absorption becomes considerably stronger over a wide wavelength range. Therefore, an advantageous window for measuring glucose and other blood constituents may be in the SWIR between 1500 and 1850 nm and 2050 to 2500 nm. These are exemplary wavelength ranges, and other ranges can be used that would still fall within the scope of this disclosure.
- wavelengths in the eye safe window may not transmit down to the retina of the eye, and therefore, these wavelengths may be less likely to create permanent eye damage.
- the near-infrared wavelengths have the potential to be dangerous, because the eye cannot see the wavelengths (as it can in the visible), yet they can penetrate and cause damage to the eye.
- wavelengths longer than about 1400 nm are substantially not transmitted to the retina or substantially absorbed in the retina, this wavelength range is known as the eye safe window.
- wavelengths longer than 1400 nm in general only the cornea of the eye may receive or absorb the light radiation.
- FIGS. 4A and 4B some of the exemplary preliminary data for glucose absorbance are illustrated in FIGS. 4A and 4B .
- the optical spectra 401 in FIG. 4A for different levels of glucose concentration in the wavelength range between 2000 and 2400 nm show the three absorption peaks near 2120 nm (2.12 ⁇ m), 2270 nm (2.27 ⁇ m) and 2320 nm (2.32 ⁇ m).
- FIG. 5 illustrates the spectrum 500 for different blood constituents in the wavelength range of 2 to 2.45 microns.
- the glucose absorption spectrum 501 can be unique with its three peaks in this wavelength range.
- other blood constituents such as triacetin 502 , ascorbate 503 , lactate 504 , alanine 505 , urea 506 , and BSA 507 also have spectral features in this wavelength range. To distinguish the glucose 501 from these overlapping spectra, it may be advantageous to have information at multiple wavelengths.
- the spectrum may be correlated with a library of known spectra to determine the overlap integrals, and a threshold function may be used to quantify the concentration of different constituents. This is just one way to perform the signal processing, and many other techniques, algorithms, and software may be used and would fall within the scope of this disclosure.
- Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver. Two of the three are used as a source of energy in the heart and brain, while the third is a waste product excreted from the body.
- the three endogenous ketone bodies are acetone, acetoacetic acid, and beta-hydroxybutyrate or 3-hydroxybutyrate, and the waste product ketone body is acetone.
- Ketone bodies may be used for energy, where they are transported from the liver to other tissues.
- the brain may utilize ketone bodies when sufficient glucose is not available for energy. For instance, this may occur during fasting, strenuous exercise, low carbohydrate, ketogenic diet and in neonates. Unlike most other tissues that have additional energy sources such as fatty acids during periods of low blood glucose, the brain cannot break down fatty acids and relies instead on ketones. In one embodiment, these ketone bodies are detected.
- Ketone bodies may also be used for reducing or eliminating symptoms of diseases or disorders characterized by impaired glucose metabolism.
- diseases associated with reduced neuronal metabolism of glucose include Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's disease), Huntington's disease and epilepsy.
- monitoring of alternate sources of ketone bodies that may be administered orally as a dietary supplement or in a nutritional composition to counteract some of the glucose metabolism impairments is performed.
- ketone bodies supplements are provided, there is also a need to monitor the ketone level in the blood stream.
- ketosis if elevated levels of ketone bodies are present in the body, this may lead to ketosis; hyperketonemia is also an elevated level of ketone bodies in the blood.
- both acetoacetic acid and beta-hydroxybutyric acid are acidic, and, if levels of these ketone bodies are too high, the pH of the blood may drop, resulting in ketoacidosis.
- ketones C n H 2n0 .
- a ketone is an organic compound with the structure RC( ⁇ O)R′, where R and R′ can be a variety of carbon-containing substituents. It features a carbonyl group (C ⁇ O) bonded to two other carbon atoms. Because the ketones contain the hydrocarbon bonds, there might be expected to be features in the SWIR, similar in structure to those found for glucose.
- the infrared spectrum 600 for the ketone 3-hydroxybutyrate is illustrated in FIG. 6 .
- glucose there are significant features in the mid- and long-wave infrared between 6 to 12 microns, but these may be difficult to observe non-invasively.
- SWIR there are some features in the SWIR that may be weaker, but they could potentially be observed non-invasively, perhaps through blood and water.
- the optical spectra 700 for ketones as well as some other blood constituents are exemplified in FIG. 7 in the wavelength range of 2100 nm to 2400 nm.
- the absorbance for ketones is 701
- the absorbance for glucose is 702.
- there are also features in this wavelength range for other blood constituents such as urea 703 , albumin or blood protein 704 , creatinine 705 , and nitrite 706 .
- the features for ketone 701 seem more spectrally pronounced than even glucose.
- the first or second derivatives of the spectra may enable better discrimination between substances.
- the first derivative may help remove any flat offset or background, while the second derivative may help to remove any sloped offset or background.
- the first or second derivative may be applied after curve fitting or smoothing the reflectance, transmittance, or absorbance.
- FIG. 8A illustrates the derivative spectra for ketone 801 and glucose 802 , which can be distinguished from the derivative spectra for protein 803 , urea 804 and creatinine 805 . Based on FIG.
- ketones 801 may have a more pronounced difference than even glucose 802 in the wavelength range between 2100 and 2400 nm. Therefore, ketone bodies should also be capable of being monitored using a non-invasive optical technique in the SWIR, and a different pattern matching library could be used for glucose and ketones.
- HbA1c Another blood constituent that may be of interest for monitoring of health or diseases is hemoglobin A1c, also known as HbA1c or glycated hemoglobin (glycol-hemoglobin or glycosylated hemoglobin).
- HbA1c is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. Thus, HbA1c may serve as a marker for average blood glucose levels over the previous months prior to the measurements.
- the measurement of HbA1c may be one of the first tests that are conducted.
- An HbA1c level less than approximately 6% may be considered normal.
- an HbA1c level greater than approximately 6.5% may be considered to be diabetic.
- higher amounts of HbA1c indicate poorer control of blood glucose levels.
- monitoring the HbA1c in diabetic patients may improve treatment.
- Current techniques for measuring HbA1c require drawing blood, which may be inconvenient and painful.
- the point-of-care devices use immunoassay or boronate affinity chromatography, as an example. Thus, there is also an unmet need for non-invasive monitoring of HbA1c.
- FIG. 2 illustrates the FTIR measurements of HbA1c absorbance 203 over the wavelength range between 1500 and 2400 nm for a concentration of approximately 1 mg/ml.
- the absorbance of hemoglobin 201 over this wavelength range is approximately flat, the HbA1c absorbance 203 shows broad features and distinct curvature.
- the HbA1c absorbance 203 does not appear to exhibit as pronounced features as glucose 202 , the non-invasive SWIR measurement should be able to detect HbA1c with appropriate pattern matching algorithms.
- the spectrum for HbA1c may be further enhanced by using first or second derivative data, as seen for ketones in FIG. 8A .
- Raman spectroscopy may require higher optical power levels.
- blood constituents such as glucose, ketone bodies, and HbA1c
- other blood constituents can also be measured using similar techniques, and these are also intended to be covered by this disclosure.
- blood constituents such as proteins, albumin, urea, creatinine or nitrites could also be measured.
- SWIR optical techniques might be used, but the pattern matching algorithms and software could use different library features or functions for the different constituents.
- the optical techniques described in this disclosure could also be used to measure levels of triglycerides.
- Triglycerides are bundles of fats that may be found in the blood stream, particularly after ingesting meals. The body manufactures triglycerides from carbohydrates and fatty foods that are eaten. In other words, triglycerides are the body's storage form of fat. Triglycerides are comprised of three fatty acids attached to a glycerol molecule, and measuring the level of triglycerides may be important for diabetics.
- the triglyceride levels or concentrations in blood may be rated as follows: desirable or normal may be less than 150 mg/dl; borderline high may be 150-199 mg/dl; high may be 200-499 mg/dl; and very high may be 500 mg/dl or greater.
- FIG. 8B illustrates one example of the near-infrared absorbance 825 for triglycerides. There are distinct absorbance peaks in the spectrum that should be measurable.
- the characteristic absorption bands may be assigned as follows: (a) the first overtones of C—H stretching vibrations (1600-1900 nm); (b) the region of second overtones of C—H stretching vibrations (1100-1250 nm); and, (c) two regions (2000-2200 nm and 1350-1500 nm) that comprise bands due to combinations of C—H stretching vibrations and other vibrational modes.
- FIG. 8C shows the near-infrared reflectance spectrum for cholesterol 850 with wavelength in microns ( ⁇ m). Distinct absorption peaks are observable near 1210 nm (1.21 ⁇ m), 1720 nm (1.72 ⁇ m), and between 2300-2500 nm (2.3-2.5 ⁇ m). Also, there are other features near 1450 nm (1.45 ⁇ m) and 2050 nm (2.05 ⁇ m).
- FIG. 8D the near-infrared reflectances 875 are displayed versus wavelength (nm) for various blood constituents.
- cholesterol 876 is overlaid with glucose 877 , albumin 878 , uric acid 879 , and urea 880 .
- glucose 877 is overlaid with glucose 877 , albumin 878 , uric acid 879 , and urea 880 .
- FIG. 8D at about 1720 nm and 2300 nm, cholesterol 876 reaches approximate reflectance peaks, while some of the other analytes are in a more gradual mode.
- Various signal processing methods may be used to identify and quantify the concentration of cholesterol 876 and/or glucose 877 , or some of the other blood constituents.
- one of the issues in measuring a particular blood constituent is the interfering and overlapping signal from other blood constituents.
- the selection of the constituent of interest may be improved using a number of techniques. For example, a higher light level or intensity may improve the signal-to-noise ratio for the measurement.
- mathematical modeling and signal processing methodologies may help to reduce the interference, such as multivariate techniques, multiple linear regression, and factor-based algorithms, for example.
- a number of mathematical approaches include multiple linear regression, partial least squares, and principal component regression (PCR).
- PCR principal component regression
- various mathematical derivatives, including the first and second derivatives may help to accentuate differences between spectra.
- a SWIR camera or infrared camera system may be used to capture the images.
- the camera may include one or more lenses on the input, which may be adjustable.
- the focal plane assemblies may be made from mercury cadmium telluride material (HgCdTe), and the detectors may also include thermo-electric coolers.
- the image sensors may be made from indium gallium arsenide (InGaAs), and CMOS transistors may be connected to each pixel of the InGaAs photodiode array.
- the camera may interface wirelessly or with a cable (e.g., USB, Ethernet cable, or fiber optics cable) to a computer or tablet or smart phone, where the images may be captured and processed.
- a cable e.g., USB, Ethernet cable, or fiber optics cable
- the variations due to sunlight and time-of-day may be factored out.
- the effects of the weather, such as clouds and rain, might also be reduced.
- higher signal-to-noise ratios may be achieved.
- one way to improve the signal-to-noise ratio would be to use modulation and lock-in techniques.
- the light source may be modulated, and then the detection system would be synchronized with the light source.
- the techniques from lock-in detection may be used, where narrow band filtering around the modulation frequency may be used to reject noise outside the modulation frequency.
- change detection schemes may be used, where the detection system captures the signal with the light source on and with the light source off. Again, for this system the light source may be modulated. Then, the signal with and without the light source is differenced. This may enable the sun light changes to be subtracted out.
- change detection may help to identify objects that change in the field of view. In the following some exemplary detection systems are described.
- the near-infrared reflectance or absorbance spectrum may be a complex combination of the tissue scattering properties that result from the concentration and characteristics of a multiplicity of tissue components including water, fat, protein, collagen, elastin, and/or glucose.
- the optical properties of the skin may also change with environmental factors such as humidity, temperature and pressure. Physiological variation may also cause changes in the tissue measurement over time and may vary based on lifestyle, health, aging, etc.
- the structure and composition of skin may also vary widely among individuals, between different sites within an individual, and over time on the same individual. Thus, the skin introduces a dynamic interference signal that may have a wide variation due to a number of parameters.
- FIG. 9 shows a schematic cross-section of human skin 900 , 901 .
- the top layer of the skin is epidermis 902 , followed by a layer of dermis 903 and then subcutaneous fat 904 below the dermis.
- the epidermis 902 with a thickness of approximately 10-150 microns, may provide a barrier to infection and loss of moisture and other body constituents.
- the dermis 903 ranges in thickness from approximately 0.5 mm to 4 mm (averages approximately 1.2 mm over most of the body) and may provide the mechanical strength and elasticity of skin.
- the dermis 903 water may account for approximately 70% of the volume.
- the next most abundant constituent in the dermis 903 may be collagen 905 , a fibrous protein comprising 70-75% of the dry weight of the dermis 903 .
- Elastin fibers 906 also a protein, may also be plentiful in the dermis 903 , although they constitute a smaller portion of the bulk.
- the dermis 903 may contain a variety of structures (e.g., sweat glands, hair follicles with adipose rich sebaceous glands 907 near their roots, and blood vessels) and other cellular constituents.
- the subcutaneous layer 904 comprising mostly adipose tissue.
- the subcutaneous layer 904 may be by volume approximately 10% water and may be comprised primarily of cells rich in triglycerides or fat.
- the concentration of glucose may vary in each layer according to a variety of factors including the water content, the relative sizes of the fluid compartments, the distribution of capillaries, the perfusion of blood, the glucose uptake of cells, the concentration of glucose in blood, and the driving forces (e.g., osmotic pressure) behind diffusion.
- FIG. 10 illustrates 1000 the absorption coefficients for water (including scattering) 1001 , adipose 1002 , collagen 1003 and elastin 1004 .
- the absorption curves for water 1001 and adipose 1002 are calibrated, whereas the absorption curves for collagen 1003 and elastin 1004 are in arbitrary units.
- vertical lines demarcating the wavelengths near 1210 nm 1005 and 1720 nm 1006 .
- the water absorption increases with increasing wavelength. With the increasing absorption beyond about 2000 nm, it may be difficult to achieve deeper penetration into biological tissue in the infrared wavelengths beyond approximately 2500 nm.
- the absorption coefficient may be useful for determining the material in which light of a certain infrared wavelength will be absorbed, to determine the penetration depth of the light of a certain wavelength may also require the addition of scattering loss to the curves.
- the water curve 1001 includes the scattering loss curve in addition to the water absorption.
- the scattering loss can be significantly higher at shorter wavelengths.
- the adipose absorption 1002 can still be higher than the water plus scattering loss 1001 .
- the total absorption can exceed the light energy lost to water absorption and light scattering at 1720 nm.
- the adipose absorption 1002 can be considerably lower than the water plus scattering loss 1001 , particularly since the scattering loss can be dominant at these shorter wavelengths.
- the interference for glucose lines observed through skin may be illustrated by overlaying the glucose lines over the absorption curves 1000 for the skin constituents.
- FIG. 2 illustrated that the glucose absorption 202 included features centered around 1587 nm, 1750 nm, 2120 nm, 2270 nm and 2320 nm.
- FIG. 10 vertical lines have been drawn at the glucose line wavelengths of 1587 nm 1007 , 1750 nm 1008 , 2120 nm 1009 , 2270 nm 1010 and 2320 nm 1011 .
- the glucose line near 1587 m 1007 may be more easily detected because it peaks while most of the other skin constituents are sloped downward toward an absorption valley.
- the glucose line near 2120 nm 1009 may also be detectable for similar reasons, although adipose may have conflicting behavior due to local absorption minimum and maximum nearby in wavelength.
- an instrument head may be designed to place one probe above a region of skin over a blood vein, while a second probe may be placed at a region of the skin without a noticeable blood vein below it. Then, by differencing the signals from the two probes, at least part of the skin interference may be cancelled out.
- the dorsal of the hand 1100 may be used for measuring blood constituents or analytes.
- the dorsal of the hand 1100 may have regions that have distinct veins 1101 as well as regions where the veins are not as shallow or pronounced 1102 . By stretching the hand and leaning it backwards, the veins 1101 may be accentuated in some cases.
- a near-infrared diffuse reflectance measurement may be performed by placing one probe 1103 above the vein-rich region 1101 . To turn this into a differential measurement, a second probe 1104 may be placed above a region without distinct veins 1102 .
- the outputs from the two probes may be subtracted 1105 to at least partially cancel out the features from the skin.
- the subtraction may be done preferably in the electrical domain, although it can also be performed in the optical domain or digitally/mathematically using sampled data based on the electrical and/or optical signals.
- the dorsal of the hand 1100 is shown, many other parts of the hand can be used within the scope of this disclosure. For example, alternate methods may use transmission through the webbing between the thumb and the fingers 1106 , or transmission or diffuse reflection through the tips of the fingers 1107 .
- the dorsal of the foot 1200 may be used instead of the hand.
- One advantage of such a configuration may be that for self-testing by a user, the foot may be easier to position the instrument using both hands.
- One probe 1203 may be placed over regions where there are more distinct veins 1201 , and a near-infrared diffuse reflectance measurement may be made.
- a second probe 1204 may be placed over a region with less prominent veins 1202 , and then the two probe signals may be subtracted, either electronically or optically, or may be digitized/sampled and processed mathematically depending on the particular application and implementation.
- the differential measurements may be intended to compensate for or subtract out (at least in part) the interference from the skin.
- this may also aid in removing some variability in the skin from environmental effects such as temperature, humidity, or pressure.
- it may be advantageous to first treat the skin before the measurement, by perhaps wiping with a cloth or treated cotton ball, applying some sort of cream, or placing an ice cube or chilled bag over the region of interest.
- the wrist may be advantageously used, particularly where a pulse rate is typically monitored. Since the pulse may be easily felt on the wrist, there is underlying the region a distinct blood flow.
- Other embodiments may use other parts of the body, such as the ear lobes, the tongue, the inner lip, the nails, the eye, or the teeth. Some of these embodiments will be further described below.
- the ear lobes or the tip of the tongue may be advantageous because they are thinner skin regions, thus permitting transmission rather than diffuse reflection. However, the interference from the skin is still a problem in these embodiments.
- the inner lip or the bottom of the tongue may be contemplated because distinct veins are observable, but still the interference from the skin may be problematic in these embodiments.
- the eye may seem as a viable alternative because it is more transparent than skin.
- the anterior chamber of the eye (the space between the cornea and the iris) comprises a fluid known as aqueous humor.
- the glucose level in the eye chamber may have a significant temporal lag on changes in the glucose level compared to the blood glucose level.
- a surface cooling apparatus 1324 may be used, where a cooling fluid may be flowed either touching or in close proximity to the skin 1321 .
- a cylindrical assembly may optionally be used, where the cylindrical length may be several millimeters in length and defined by a clamp or mount 1323 placed on or near the leg.
- the light input 1327 may be received from a light source, which may use a fiber or fiber bundles to couple the light to the lens/mirror assembly 1326 .
- a lens and/or mirror assembly 1326 may be used to couple the light input 1327 to the lenslet array or window 1325 , either directly or indirectly.
- the lens and/or mirror assembly 1326 may also be coupled to the clamp or mount assembly 1323 .
- a window and/or lenslet array 1325 is also shown on the cylindrical surface for permitting the light to be incident on the skin 1321 and varicose vein 1322 at multiple spots.
- the lenslet array 1325 may comprise circular, spherical or cylindrical lenses, depending on the type of spots desired. As before, one advantage of placing the lenslet array 1325 in close proximity to the skin 1321 may be that a high NA lens may be used. Also, the input from the lens and/or mirror assembly to the lenslet array 1325 may be a single large beam, or a plurality of smaller beams. In one embodiment, a plurality of spots may be created by the lenslet array 1325 . Although four spots are shown in FIG. 13A , any number of spots may be used and are intended to be covered by this disclosure.
- the lens and/or mirror assemblies may comprise one or more lenses, microscope objectives, curved or flat mirrors, lens tipped fibers, or some combination of these elements.
- the optics such as used in a camera may be employed in this arrangement, provided that the optics are substantially transparent at the light wavelengths being used.
- reflections and losses through the optics may be reduced by applying anti-reflection coatings, and chromatic dispersion may be reduced by using reflective optics rather than refractive optics.
- FIG. 13B illustrates a typical human nail tissue structure 1300 and the capillary vessels below it.
- the fingernail 1301 is approximately 1 mm thick, and below this resides a layer of epidermis 1302 with a thickness of approximately 1 mm.
- the dermis 1304 is also shown, and within particularly the top about 0.5 mm of dermis are a significant number of capillary vessels.
- the light exposed on the top of the fingernail must penetrate about 2-2.5 mm or more, and the reflected light (round trip passage) should be sufficiently strong to measure.
- the distance required to penetrate could be reduced by drilling a hole in the fingernail 1301 .
- FIG. 14 illustrates the attenuation coefficient 1400 for seven nail samples that are allowed to stand in an environment with a humidity level of 14%. These coefficients are measured using an FTIR spectrometer over the near-infrared wavelength range of approximately 1 to 2.5 microns. These spectra are believed to correspond to the spectra of keratin contained in the nail plate. The base lines for the different samples are believed to differ because of the influence of scattering. Several of the absorption peaks observed correspond to peaks of keratin absorption, while other features may appear from the underlying epidermis and dermis. It should also be noted that the attenuation coefficients 1400 also vary considerably depending on humidity level or water content as well as temperature and other environmental factors. Moreover, the attenuation coefficient may also change in the presence of nail polish of various sorts.
- the large variations in attenuation coefficient for fingernails also may interfere with the absorption peaks of glucose.
- FIG. 14 the fingernail spectrum is also shown the glucose spectrum 1401 for two different glucose concentrations.
- the vertical lines 1402 , 1403 , 1404 , 1405 and 1406 are drawn to illustrate the glucose absorption peaks and where they lie on the fingernail spectra 1400 .
- the nail has interfering features that may be similar to skin, particularly since both have spectra that vary not only in wavelength but also with environmental factors. In one embodiment, it may be possible to see the glucose peaks 1402 and 1404 through the fingernail, but it may be much more difficult to observe the glucose peaks near 1403 , 1405 and 1406 .
- FIG. 15 illustrates an exemplary structure of a tooth 1500 .
- the tooth 1500 has a top layer called the crown 1501 and below that a root 1502 that reaches well into the gum 1506 and bone 1508 of the mouth.
- the exterior of the crown 1501 is an enamel layer 1503
- Below the enamel is a layer of dentine 1504 that sits atop a layer of cementum 1507 .
- Below the dentine 1504 is a pulp region 1505 , which comprises within it blood vessels 1509 and nerves 1510 . If the light can penetrate the enamel 1503 and dentine 1504 , then the blood flow and blood constituents can be measured through the blood vessels in the dental pulp 1505 . While it may be true that the amount of blood flow in the dental pulp 1505 may be less since it comprises capillaries, the smaller blood flow could still be advantageous if there is less interfering spectral features from the tooth.
- FIG. 16A illustrates the attenuation coefficient 1600 for dental enamel 1601 (filled circles) and the absorption coefficient of water 1602 (open circles) versus wavelength. Near-infrared light may penetrate much further without scattering through all the tooth enamel, due to the reduced scattering coefficient in normal enamel.
- Scattering in enamel may be fairly strong in the visible, but decreases as approximately 1/wavelength 3 (i.e., inverse of the wavelength cubed) with increasing wavelength to a value of only 2-3 cm ⁇ 1 at 1310 nm and 1550 nm in the near infrared. Therefore, enamel may be virtually transparent in the near infrared with optical attenuation 1-2 orders of magnitude less than in the visible range.
- FIG. 16B illustrates the absorption spectrum 1650 of intact enamel 1651 (dashed line) and dentine 1652 (solid line) in the wavelength range of approximately 1.2 to 2.4 microns.
- the band with a peak around 1.57 microns may be attributed to the overtone of valent vibration of water present in both enamel and dentine.
- the absorption is greater for dentine than for enamel, which may be related to the large water content in this tissue.
- dentine may have two absorption bands, and enamel one.
- the band with a maximum near 2.1 microns may belong to the overtone of vibration of PO hydroxyapatite groups, which is the main substance of both enamel and dentine. Moreover, the band with a peak near 1.96 microns in dentine may correspond to water absorption (dentine may contain substantially higher water than enamel).
- FIG. 17 shows the near infrared spectral reflectance 1700 over the wavelength range of approximately 800 nm to 2500 nm from an occlusal (e.g., top/bottom) tooth surface 1704 .
- the curve with black diamonds 1701 corresponds to the reflectance from a sound, intact tooth section.
- the curve with asterisks * 1702 corresponds to a tooth section with an enamel lesion.
- the curve with circles 1703 corresponds to a tooth section with a dentine lesion.
- the shapes of the spectra remain similar, but the amplitude of the reflection changes with lesions.
- an intact tooth 1701 has low reflectance (e.g., high transmission), and the reflectance appears to be more or less independent of wavelength.
- the scattering loss may be wavelength dependent. For example, the scattering loss may decrease as 1/(wavelength) 3 —so, the scattering loss decreases with longer wavelengths.
- the dips near 1450 nm and 1900 nm correspond to water absorption, and the reflectance dips are particularly pronounced in the dentine lesion 1703 .
- One other benefit of the absorption, transmission or reflectance in the near infrared may be that stains and non-calcified plaque are not visible in this wavelength range, enabling better discrimination of defects, cracks, and demineralized areas.
- the teeth appear to introduce much less interference for non-invasive monitoring of blood constituents.
- the few features in FIG. 16B or 17 may be calibrated out of the measurement.
- using an intact tooth 1701 may further minimize any interfering signals.
- the tooth comprises relatively hard tissue, higher power from the light sources in the near infrared may be used without damaging the tissue, such as with skin.
- the light source may output a plurality of wavelengths, or a continuous spectrum over a range of wavelengths. In a preferred embodiment, the light source may cover some or all of the wavelength range between approximately 1400 nm and 2500 nm.
- the signal may be received at a receiver, which may also comprise a spectrometer or filters to discriminate between different wavelengths.
- the signal may also be received at a camera, which may also comprise filters or a spectrometer.
- the spectral discrimination using filters or a spectrometer may be placed after the light source rather than at the receiver.
- the receiver usually comprises one or more detectors (optical-to-electrical conversion element) and electrical circuitry.
- the receiver may also be coupled to analog to digital converters, particularly if the signal is to be fed to a digital device.
- one or more light sources 1511 may be used for illumination.
- a transmission measurement may be performed by directing the light source output 1511 to the region near the interface between the gum 1506 and dentine 1504 .
- the light may be directed using a light guide or a fiber optic. The light may then propagate through the dental pulp 1505 to the other side, where the light may be incident on one or more detectors or another light guide to transport the signal to a spectrometer, receiver or camera 1512 .
- the light source may be directed to one or more locations near the interface between the gum 1506 and dentine 1504 (in one example, could be from the two sides of the tooth).
- the transmitted light may then be detected in the occlusal surface above the tooth using a spectrometer, receiver, or camera 1512 .
- a reflectance measurement may be conducted by directing the light source output 1511 to, for example, the occlusal surface of the tooth, and then detecting the reflectance at a spectrometer, receiver or camera 1513 .
- the human interface for the non-invasive measurement of blood constituents may be of various forms.
- a “clamp” design 1800 may be used cap over one or more teeth, as illustrated in FIG. 18A .
- the clamp design may be different for different types of teeth, or it may be flexible enough to fit over different types of teeth.
- different types of teeth include the molars (toward the back of the mouth), the premolars, the canine, and the incisors (toward the front of the mouth).
- One embodiment of the clamp-type design is illustrated in FIG. 18A for a molar tooth 1808 .
- the C-clamp 1801 may be made of a plastic or rubber material, and it may comprise a light source input 1802 and a detector output 1803 on the front or back of the tooth.
- the light source input 1802 may comprise a light source directly, or it may have light guided to it from an external light source. Also, the light source input 1802 may comprise a lens system to collimate or focus the light across the tooth.
- the detector output 1803 may comprise a detector directly, or it may have a light guide to transport the signal to an external detector element.
- the light source input 1802 may be coupled electrically or optically through 1804 to a light input 1806 .
- the coupling element 1804 may be a light guide, such as a fiber optic.
- the coupling element 1804 may be electrical wires connecting to a power supply in 1806 .
- the detector output 1803 may be coupled to a detector output unit 1807 with a coupling element 1805 , which may be one or more electrical wires or a light guide, such as a fiber optic.
- a coupling element 1805 may be one or more electrical wires or a light guide, such as a fiber optic. This is just one example of a clamp over one or more teeth, but other embodiments may also be used and are intended to be covered by this disclosure.
- one or more light source ports and sensor ports may be used in a mouth-guard type design.
- a dental mouth guard 1850 is illustrated in FIG. 18B .
- the structure of the mouth guard 1851 may be similar to mouth guards used in sports (e.g., when playing football or boxing) or in dental trays used for applying fluoride treatment, and the mouth guard may be made from plastic or rubber materials, for example.
- the mouth guard may have one or more light source input ports 1852 , 1853 and one or more detector output ports 1854 , 1855 . Although six input and output ports are illustrated, any number of ports may be used.
- the light source inputs 1852 , 1853 may comprise one or more light sources directly, or they may have light guided to them from an external light source. Also, the light source inputs 1852 , 1853 may comprise lens systems to collimate or focus the light across the teeth.
- the detector outputs 1854 , 1855 may comprise one or more detectors directly, or they may have one or more light guides to transport the signals to an external detector element.
- the light source inputs 1852 , 1853 may be coupled electrically or optically through 1856 to a light input 1857 . For example, if the light source is external in 1857 , then the one or more coupling elements 1856 may be one or more light guides, such as a fiber optic.
- the coupling element 1856 may be one or more electrical wires connecting to a power supply in 1857 .
- the detector outputs 1854 , 1855 may be coupled to a detector output unit 1859 with one or more coupling elements 1858 , which may be one or more electrical wires or one or more light guides, such as a fiber optic.
- This is just one example of a mouth guard design covering a plurality of teeth, but other embodiments may also be used and are intended to be covered by this disclosure.
- the position of the light source inputs and detector output ports could be exchanged, or some mixture of locations of light source inputs and detector output ports could be used.
- the light sources and detectors may be on the same side of the tooth.
- the detection system may be able to reject background or spurious signals and increase the signal-to-noise ratio of the measurement.
- FIG. 18 Other elements may be added to the human interface designs of FIG. 18 and are also intended to be covered by this disclosure. For instance, in one embodiment it may be desirable to have replaceable inserts that may be disposable. Particularly in a doctor's office or hospital setting, the same instrument may be used with a plurality of patients. Rather than disinfecting the human interface after each use, it may be preferable to have disposable inserts that can be thrown away after each use.
- a thin plastic coating material may enclose the clamp design of FIG. 18A or mouth guard design of FIG. 18B . The coating material may be inserted before each use, and then after the measurement is exercised the coating material may be peeled off and replaced.
- Any coating material or other disposable device may be constructed of a material having suitable optical properties that may be considered during processing of the signals used to detect any anomalies in the teeth.
- the near-infrared (NIR) region of the electromagnetic spectrum covers between approximately 0.7 microns (700 nm) to about 2.5 microns (2500 nm).
- NIR near-infrared
- One reason for preferring the SWIR over the entire NIR may be to operate in the so-called “eye-safe” window, which corresponds to wavelengths longer than about 1400 nm. While the SWIR is used for illustrative purposes, it should be clear that the discussion that follows could also apply to using the NIR wavelength range, or other wavelength bands.
- SWIR short wave infrared
- Other wavelength ranges may also be used for the applications described in this disclosure, so the discussion below is merely provided for exemplary types of light sources.
- the SWIR wavelength range may be valuable for a number of reasons.
- the SWIR corresponds to a transmission window through water and the atmosphere.
- 302 in FIG. 3A and 1602 in FIG. 16A illustrate the water transmission windows.
- wavelengths in the SWIR have similar transmission windows due to water vapor in the atmosphere.
- the so-called “eye-safe” wavelengths are wavelengths longer than approximately 1400 nm.
- the SWIR covers the wavelength range for nonlinear combinations of stretching and bending modes as well as the first overtone of C—H stretching modes.
- glucose and ketones among other substances may have unique signatures in the SWIR.
- many solids have distinct spectral signatures in the SWIR, so particular solids may be identified using stand-off detection or remote sensing.
- many explosives have unique signatures in the SWIR.
- Different light sources may be selected for the SWIR based on the needs of the application. Some of the features for selecting a particular light source include power or intensity, wavelength range or bandwidth, spatial or temporal coherence, spatial beam quality for focusing or transmission over long distance, and pulse width or pulse repetition rate.
- lamps light emitting diodes (LEDs), laser diodes (LD's), tunable LD's, super-luminescent laser diodes (SLDs), fiber lasers or super-continuum sources (SC) may be advantageously used.
- LEDs light emitting diodes
- LD's laser diodes
- SLDs super-luminescent laser diodes
- SC super-continuum sources
- different fibers may be used for transporting the light, such as fused silica fibers, plastic fibers, mid-infrared fibers (e.g., tellurite, chalcogenides, fluorides, ZBLAN, etc), or a hybrid of these fibers.
- Lamps may be used if low power or intensity of light is required in the SWIR, and if an incoherent beam is suitable.
- an incandescent lamp that can be used is based on tungsten and halogen, which have an emission wavelength between approximately 500 nm to 2500 nm.
- thermal sources where the SWIR radiation is based on the black body radiation from the hot object.
- the thermal and lamp based sources are broadband and have low intensity fluctuations, it may be difficult to achieve a high signal-to-noise ratio in a non-invasive blood constituent measurement due to the low power levels.
- the lamp based sources tend to be energy inefficient.
- LED's can be used that have a higher power level in the SWIR wavelength range. LED's also produce an incoherent beam, but the power level can be higher than a lamp and with higher energy efficiency. Also, the LED output may more easily be modulated, and the LED provides the option of continuous wave or pulsed mode of operation. LED's are solid state components that emit a wavelength band that is of moderate width, typically between about 20 nm to 40 nm. There are also so-called super-luminescent LEDs that may even emit over a much wider wavelength range. In another embodiment, a wide band light source may be constructed by combining different LEDs that emit in different wavelength bands, some of which could preferably overlap in spectrum. One advantage of LEDs as well as other solid state components is the compact size that they may be packaged into.
- various types of laser diodes may be used in the SWIR wavelength range.
- LEDs may be higher in power but narrower in wavelength emission than lamps and thermal sources
- the LDs may be yet higher in power but yet narrower in wavelength emission than LEDs.
- Different kinds of LDs may be used, including Fabry-Perot LDs, distributed feedback (DFB) LDs, distributed Bragg reflector (DBR) LDs. Since the LDs have relatively narrow wavelength range (typically under 10 nm), in one embodiment a plurality of LDs may be used that are at different wavelengths in the SWIR.
- DFB distributed feedback
- DBR distributed Bragg reflector
- LDs having emission spectra near some or all of the glucose spectral peaks (e.g., near 1587 nm, 1750 nm, 2120 nm, 2270 nm, and 2320 nm).
- the various LDs may be spatially multiplexed, polarization multiplexed, wavelength multiplexed, or a combination of these multiplexing methods.
- the LDs may be fiber pig-tailed or have one or more lenses on the output to collimate or focus the light.
- Another advantage of LDs is that they may be packaged compactly and may have a spatially coherent beam output.
- tunable LDs that can tune over a range of wavelengths are also available.
- the tuning may be done by varying the temperature, or electrical current may be used in particular structures, such as distributed Bragg reflector LDs.
- external cavity LDs may be used that have a tuning element, such as a fiber grating or a bulk grating, in the external cavity.
- super-luminescent laser diodes may provide higher power as well as broad bandwidth.
- An SLD is typically an edge emitting semiconductor light source based on super-luminescence (e.g., this could be amplified spontaneous emission).
- SLDs combine the higher power and brightness of LDs with the low coherence of conventional LEDs, and the emission band for SLD's may be 5 to 100 nm wide, preferably in the 60 to 100 nm range.
- SLDs are commercially available in the wavelength range of approximately 400 nm to 1700 nm, SLDs could and may in the future be made to cover a broader region of the SWIR.
- high power LDs for either direct excitation or to pump fiber lasers and SC light sources may be constructed using one or more laser diode bar stacks.
- FIG. 19 shows an example of the block diagram 1900 or building blocks for constructing the high power LDs.
- one or more diode bar stacks 1901 may be used, where the diode bar stack may be an array of several single emitter LDs. Since the fast axis (e.g., vertical direction) may be nearly diffraction limited while the slow-axis (e.g., horizontal axis) may be far from diffraction limited, different collimators 1902 may be used for the two axes.
- the brightness may be increased by spatially combining the beams from multiple stacks 1903 .
- the combiner may include spatial interleaving, it may include wavelength multiplexing, or it may involve a combination of the two. Different spatial interleaving schemes may be used, such as using an array of prisms or mirrors with spacers to bend one array of beams into the beam path of the other. In another embodiment, segmented mirrors with alternate high-reflection and anti-reflection coatings may be used.
- the brightness may be increased by polarization beam combining 1904 the two orthogonal polarizations, such as by using a polarization beam splitter. In one embodiment, the output may then be focused or coupled into a large diameter core fiber.
- typical dimensions for the large diameter core fiber range from approximately 100 microns in diameter to 400 microns or more.
- a custom beam shaping module 1905 may be used, depending on the particular application.
- the output of the high power LD may be used directly 1906 , or it may be fiber coupled 1907 to combine, integrate, or transport the high power LD energy.
- These high power LDs may grow in importance because the LD powers can rapidly scale up.
- the power instead of the power being limited by the power available from a single emitter, the power may increase in multiples depending on the number of diodes multiplexed and the size of the large diameter fiber.
- FIG. 19 is shown as one embodiment, some or all of the elements may be used in a high power LD, or additional elements may also be used.
- Each of the light sources described above have particular strengths, but they also may have limitations. For example, there is typically a trade-off between wavelength range and power output. Also, sources such as lamps, thermal sources, and LEDs produce incoherent beams that may be difficult to focus to a small area and may have difficulty propagating for long distances.
- An alternative source that may overcome some of these limitations is an SC light source. Some of the advantages of the SC source may include high power and intensity, wide bandwidth, spatially coherent beam that can propagate nearly transform limited over long distances, and easy compatibility with fiber delivery.
- Supercontinuum lasers may combine the broadband attributes of lamps with the spatial coherence and high brightness of lasers.
- SC modulational instability initiated supercontinuum
- COTS commercial-off-the-shelf
- the fiber laser architecture may be a platform where SC in the visible, near-infrared/SWIR, or mid-IR can be generated by appropriate selection of the amplifier technology and the SC generation fiber.
- SC lasers were used primarily in laboratory settings since typically large, table-top, mode-locked lasers were used to pump nonlinear media such as optical fibers to generate SC light.
- those large pump lasers may now be replaced with diode lasers and fiber amplifiers that gained maturity in the telecommunications industry.
- an all-fiber-integrated, high-powered SC light source 2000 may be elegant for its simplicity ( FIG. 20 ).
- the light may be first generated from a seed laser diode 2001 .
- the seed LD 2001 may be a distributed feedback laser diode with a wavelength near 1542 or 1550 nm, with approximately 0.5-2.0 ns pulsed output, and with a pulse repetition rate between a kilohertz to about 100 MHz or more.
- the output from the seed laser diode may then be amplified in a multiple-stage fiber amplifier 2002 comprising one or more gain fiber segments.
- the first stage pre-amplifier 2003 may be designed for optimal noise performance.
- the pre-amplifier 2003 may be a standard erbium-doped fiber amplifier or an erbium/ytterbium doped cladding pumped fiber amplifier.
- band-pass filters 2004 to block amplified spontaneous emission and isolators 2005 to prevent spurious reflections.
- the power amplifier stage 2006 may use a cladding-pumped fiber amplifier that may be optimized to minimize nonlinear distortion.
- the power amplifier fiber 2006 may also be an erbium-doped fiber amplifier, if only low or moderate power levels are to be generated.
- the SC generation 2007 may occur in the relatively short lengths of fiber that follow the pump laser.
- the SC fiber length may range from a few millimeters to 100 m or more.
- the SC generation may occur in a first fiber 2008 where the modulational-instability initiated pulse break-up primarily occurs, followed by a second fiber 2009 where the SC generation and spectral broadening primarily occurs.
- one or two meters of standard single-mode fiber (SMF) after the power amplifier stage may be followed by several meters of SC generation fiber.
- SMF standard single-mode fiber
- the peak power may be several kilowatts and the pump light may fall in the anomalous group-velocity dispersion regime—often called the soliton regime.
- the nanosecond pulses may be unstable due to a phenomenon known as modulational instability, which is basically parametric amplification in which the fiber nonlinearity helps to phase match the pulses.
- the nanosecond pump pulses may be broken into many shorter pulses as the modulational instability tries to form soliton pulses from the quasi-continuous-wave background.
- modulational instability in the short length of SMF fiber may form approximately 0.5 ps to several-picosecond-long pulses with high intensity.
- the few meters of SMF fiber may result in an output similar to that produced by mode-locked lasers, except in a much simpler and cost-effective manner.
- the short pulses created through modulational instability may then be coupled into a nonlinear fiber for SC generation.
- the nonlinear mechanisms leading to broadband SC may include four-wave mixing or self-phase modulation along with the optical Raman effect. Since the Raman effect is self-phase-matched and shifts light to longer wavelengths by emission of optical photons, the SC may spread to longer wavelengths very efficiently.
- the short-wavelength edge may arise from four-wave mixing, and often times the short wavelength edge may be limited by increasing group-velocity dispersion in the fiber. In many instances, if the particular fiber used has sufficient peak power and SC fiber length, the SC generation process may fill the long-wavelength edge up to the transmission window.
- Mature fiber amplifiers for the power amplifier stage 2006 include ytterbium-doped fibers (near 1060 nm), erbium-doped fibers (near 1550 nm), erbium/ytterbium-doped fibers (near 1550 nm), or thulium-doped fibers (near 2000 nm).
- candidates for SC fiber 2009 include fused silica fibers (for generating SC between 0.8-2.7 ⁇ m), mid-IR fibers such as fluorides, chalcogenides, or tellurites (for generating SC out to 4.5 ⁇ m or longer), photonic crystal fibers (for generating SC between 0.4 and 1.7 ⁇ m), or combinations of these fibers. Therefore, by selecting the appropriate fiber-amplifier doping for 2006 and nonlinear fiber 2009 , SC may be generated in the visible, near-IR/SWIR, or mid-IR wavelength region.
- the configuration 2000 of FIG. 20 is just one particular example, and other configurations can be used and are intended to be covered by this disclosure.
- further gain stages may be used, and different types of lossy elements or fiber taps may be used between the amplifier stages.
- the SC generation may occur partially in the amplifier fiber and in the pig-tails from the pump combiner or other elements.
- polarization maintaining fibers may be used, and a polarizer may also be used to enhance the polarization contrast between amplifier stages.
- driver electronics pump laser diodes, safety shut-offs, and thermal management and packaging.
- FIG. 21 One example of an SC laser that operates in the SWIR used in one embodiment is illustrated in FIG. 21 .
- This SWIR SC source 2100 produces an output of up to approximately 5 W over a spectral range of about 1.5 to 2.4 microns, and this particular laser is made out of polarization maintaining components.
- the seed laser 2101 is a distributed feedback (DFB) laser operating near 1542 nm producing approximately 0.5 nanosecond (ns) pulses at an about 8 MHz repetition rate.
- the pre-amplifier 2102 is forward pumped and uses about 2 m length of erbium/ytterbium cladding pumped fiber 2103 (often also called dual-core fiber) with an inner core diameter of 12 microns and outer core diameter of 130 microns.
- the pre-amplifier gain fiber 2103 is pumped using a 10 W 940 nm laser diode 2105 that is coupled in using a fiber combiner 2104 .
- the mid-stage between amplifier stages 2102 and 2106 comprises an isolator 2107 , a band-pass filter 2108 , a polarizer 2109 and a fiber tap 2110 .
- the power amplifier 2106 uses a 4 m length of the 12/130 micron erbium/ytterbium doped fiber 2111 that is counter-propagating pumped using one or more 30 W 940 nm laser diodes 2112 coupled in through a combiner 2113 .
- An approximately 1-2 meter length of the combiner pig-tail helps to initiate the SC process, and then a length of PM-1550 fiber 2115 (polarization maintaining, single-mode, fused silica fiber optimized for 1550 nm) is spliced 2114 to the combiner output.
- PM-1550 fiber 2115 polarization maintaining, single-mode, fused silica fiber optimized for 1550 nm
- the resulting output spectrum 2200 is shown in FIG. 22 .
- the details of the output spectrum 2200 depend on the peak power into the fiber, the fiber length, and properties of the fiber such as length and core size, as well as the zero dispersion wavelength and the dispersion properties. For example, if a shorter length of fiber is used, then the spectrum actually reaches to longer wavelengths (e.g., a 2 m length of SC fiber broadens the spectrum to ⁇ 2500 nm). Also, if extra-dry fibers are used with less O—H content, then the wavelength edge may also reach to a longer wavelength.
- the pump wavelength (in this case .about.1542 nm) should be close to the zero dispersion wavelength in the fiber.
- the short wavelength edge may shift to shorter wavelengths.
- the seed laser 2101 may be a 1064 nm distributed feedback (DFB) laser diode
- the pre-amplifier gain fiber 2103 may be a ytterbium-doped fiber amplifier with 10/125 microns dimensions
- the pump laser 2105 may be a 10 W 915 nm laser diode.
- DFB distributed feedback
- a mode field adapter may be included in addition to the isolator 2107 , band pass filter 2108 , polarizer 2109 and tap 2110 .
- the gain fiber 2111 in the power amplifier may be a 20 m length of ytterbium-doped fiber with 25/400 microns dimension for example.
- the pump 2112 for the power amplifier may be up to six pump diodes providing 30 W each near 915 nm, for example. For this much pump power, the output power in the SC may be as high as 50 W or more.
- the top SC source of FIG. 23 can lead to bandwidths ranging from about 1400 nm to 1800 nm or broader, while the lower SC source of FIG. 23 can lead to bandwidths ranging from about 1900 nm to 2500 nm or broader. Since these wavelength ranges are shorter than about 2500 nm, the SC fiber can be based on fused silica fiber.
- SC fibers include standard single-mode fiber SMF, high-nonlinearity fiber, high-NA fiber, dispersion shifted fiber, dispersion compensating fiber, and photonic crystal fibers.
- Non-fused-silica fibers can also be used for SC generation, including chalcogenides, fluorides, ZBLAN, tellurites, and germanium oxide fibers.
- the top of FIG. 23 illustrates a block diagram for an SC source 2300 capable of generating light between approximately 1400 and 1800 nm or broader.
- a pump fiber laser similar to FIG. 21 can be used as the input to a SC fiber 2309 .
- the seed laser diode 2301 can comprise a DFB laser that generates, for example, several milliwatts of power around 1542 or 1553 nm.
- the fiber pre-amplifier 2302 can comprise an erbium-doped fiber amplifier or an erbium/ytterbium doped double clad fiber.
- a mid-stage amplifier 2303 can be used, which can comprise an erbium/ytterbium doped double-clad fiber.
- a bandpass filter 2305 and isolator 2306 may be used between the pre-amplifier 2302 and mid-stage amplifier 2303 .
- the power amplifier stage 2304 can comprise a larger core size erbium/ytterbium doped double-clad fiber, and another bandpass filter 2307 and isolator 2308 can be used before the power amplifier 2304 .
- the output of the power amplifier can be coupled to the SC fiber 2309 to generate the SC output 2310 . This is just one exemplary configuration for an SC source, and other configurations or elements may be used consistent with this disclosure.
- the bottom of FIG. 23 illustrates a block diagram for an SC source 2350 capable of generating light between approximately 1900 and 2500 nm or broader.
- the seed laser diode 2351 can comprise a DFB or DBR laser that generates, for example, several milliwatts of power around 1542 or 1553 nm.
- the fiber pre-amplifier 2352 can comprise an erbium-doped fiber amplifier or an erbium/ytterbium doped double-clad fiber.
- a mid-stage amplifier 2353 can be used, which can comprise an erbium/ytterbium doped double-clad fiber.
- a bandpass filter 2355 and isolator 2356 may be used between the pre-amplifier 2352 and mid-stage amplifier 2353 .
- the power amplifier stage 2354 can comprise a thulium doped double-clad fiber, and another isolator 2357 can be used before the power amplifier 2354 .
- the output of the mid-stage amplifier 2353 can be approximately near 1550 nm, while the thulium-doped fiber amplifier 2354 can amplify wavelengths longer than approximately 1900 nm and out to about 2100 nm. Therefore, for this configuration wavelength shifting may be required between 2353 and 2354.
- the wavelength shifting can be accomplished using a length of standard single-mode fiber 2358 , which can have a length between approximately 5 and 50 meters, for example.
- the output of the power amplifier 2354 can be coupled to the SC fiber 2359 to generate the SC output 2360 .
- the various amplifier stages can comprise different amplifier types, such as erbium doped fibers, ytterbium doped fibers, erbium/ytterbium co-doped fibers and thulium doped fibers.
- One advantage of the SC lasers illustrated in FIGS. 20-23 are that they may use all-fiber components, so that the SC laser can be all-fiber, monolithically integrated with no moving parts. The all-integrated configuration can consequently be robust and reliable.
- FIGS. 20-23 are examples of SC light sources that may be advantageously used for SWIR light generation in various medical diagnostic and therapeutic applications.
- the SC generation fiber could be pumped by a mode-locked laser, a gain-switched semiconductor laser, an optically pumped semiconductor laser, a solid state laser, other fiber lasers, or a combination of these types of lasers.
- a liquid or a gas cell might be used as the nonlinear medium in which the spectrum is to be broadened.
- the pre-amplifier stage 2102 might be removed, along with at least some of the mid-stage elements.
- the gain fiber could be double passed to emulate a two stage amplifier. In this example, the pre-amplifier stage 2102 might be removed, and perhaps also some of the mid-stage elements.
- a mirror or fiber grating reflector could be placed after the power amplifier stage 2106 that may preferentially reflect light near the wavelength of the seed laser 2101 . If the mirror or fiber grating reflector can transmit the pump light near 940 nm, then this could also be used instead of the pump combiner 2113 to bring in the pump light 2112 .
- the SC fiber 2115 could be placed between the seed laser 2101 and the power amplifier stage 2106 (SC is only generated after the second pass through the amplifier, since the power level may be sufficiently high at that time).
- an output coupler may be placed between the seed laser diode 2101 and the SC fiber, which now may be in front of the power amplifier 2106 .
- the output coupler could be a power coupler or divider, a dichroic coupler (e.g., passing seed laser wavelength but outputting the SC wavelengths), or a wavelength division multiplexer coupler.
- a dichroic coupler e.g., passing seed laser wavelength but outputting the SC wavelengths
- a wavelength division multiplexer coupler e.g., a wavelength division multiplexer coupler
- the non-invasive blood constituent or analytes measurement device may also benefit from communicating the data output to the “cloud” (e.g., data servers and processors in the web remotely connected) via wired and/or wireless communication strategies.
- the non-invasive devices may be part of a series of biosensors applied to the patient, and collectively these devices form what might be called a body area network or a personal area network.
- the biosensors and non-invasive devices may communicate to a smart phone, tablet, personal data assistant, computer, and/or other microprocessor-based device, which may in turn wirelessly or over wire and/or fiber optically transmit some or all of the signal or processed data to the internet or cloud.
- the cloud or internet may in turn send the data to doctors or health care providers as well as the patients themselves.
- the physiological measurement device or non-invasive blood constituent measurement device 2401 may comprise a transmitter 2403 to communicate over a first communication link 2404 in the body area network or personal area network to a receiver in a smart phone, tablet cell phone, PDA, or computer 2405 .
- a processor 2402 may process some of the physiological data, since with processing the amount of data to transmit may be less (hence, more energy efficient).
- the first communication link 2404 may operate through the use of one of many wireless technologies such as Bluetooth, Zigbee, WiFi, IrDA (infrared data association), wireless USB, or Z-wave, to name a few.
- the communication link 2404 may occur in the wireless medical band between 2360 and 2390 MHz, which the FCC allocated for medical body area network devices, or in other designated medical device or WMTS bands. These are examples of devices that can be used in the body area network and surroundings, but other devices could also be used and are included in the scope of this disclosure.
- the personal device 2405 may store, process, display, and transmit some of the data from the measurement device 2401 .
- the device 2405 may comprise a receiver, transmitter, display, voice control and speakers, and one or more control buttons or knobs and a touch screen. Examples of the device 2405 include smart phones such as the Apple iPhones® or phones operating on the Android or Microsoft systems.
- the device 2405 may have an application, software program, or firmware to receive and process the data from the measurement device 2401 .
- the device 2405 may then transmit some or all of the data or the processed data over a second communication link 2406 to the internet or “cloud” 2407 .
- the second communication link 2406 may advantageously comprise at least one segment of a wireless transmission link, which may operate using WiFi or the cellular network.
- the second communication link 2406 may additionally comprise lengths of fiber optic and/or communication over copper wires or cables.
- the internet or cloud 2407 may add value to the measurement device 2401 by providing services that augment the physiological data collected.
- some of the functions performed by the cloud include: (a) receive at least a fraction of the data from the device 2405 ; (b) buffer or store the data received; (c) process the data using software stored on the cloud; (d) store the resulting processed data; and (e) transmit some or all of the data either upon request or based on an alarm.
- the data or processed data may be transmitted 2408 back to the originator (e.g., patient or user), it may be transmitted 2409 to a health care provider or doctor, or it may be transmitted 2410 to other designated recipients.
- the cloud 2407 may provide a number of value-add services.
- the cloud application may store and process the physiological data for future reference or during a visit with the healthcare provider. If a patient has some sort of medical mishap or emergency, the physician can obtain the history of the physiological parameters over a specified period of time. In another embodiment, if the physiological parameters fall out of acceptable range, alarms may be delivered to the user 2408 , the healthcare provider 2409 , or other designated recipients 2410 .
- the device 2405 may also have a GPS sensor, so the cloud 2407 may be able to provide time, data and position along with the physiological parameters.
- the cloud 2407 could provide the location of the patient to the healthcare provider 2409 or other designated recipients 2410 .
- the digitized data in the cloud 2407 may help to move toward what is often called “personalized medicine.” Based on the physiological parameter data history, medication or medical therapies may be prescribed that are customized to the particular patient.
- the cloud application 2407 and application on the device 2405 may also have financial value for companies developing measurement devices 2401 such as a non-invasive blood constituent monitor.
- measurement devices 2401 such as a non-invasive blood constituent monitor.
- the companies make the majority of their revenue on the measurement strips.
- a non-invasive monitor there is no need for strips, so there is less of an opportunity for recurring costs (e.g., the razor/razor blade model does not work for non-invasive devices).
- people may be willing to pay a periodic fee for the value-add services provided on the cloud 2407 . Diabetic patients, for example, would probably be willing to pay a periodic fee for monitoring their glucose levels, storing the history of the glucose levels, and having alarm warnings when the glucose level falls out of range.
- ketone bodies supplement for treatment of disorders characterized by impaired glucose metabolism may need to monitor their ketone bodies level.
- impaired glucose metabolism e.g., Alzheimer's, Parkinson's, Huntington's or ALS
- these patients would also probably be willing to pay a periodic fee for the value-add services provided on the cloud 2407 .
- businesses can build a recurring cost business model even using non-invasive measurement devices.
- Described herein are just some examples of the beneficial use of near-infrared or SWIR lasers for non-invasive monitoring of glucose, ketones, HbA1c and other blood constituents.
- many other medical procedures can use the near-infrared or SWIR light consistent with this disclosure and are intended to be covered by the disclosure.
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Health & Medical Sciences (AREA)
- Pathology (AREA)
- Biomedical Technology (AREA)
- General Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Biophysics (AREA)
- Chemical & Material Sciences (AREA)
- Medical Informatics (AREA)
- Public Health (AREA)
- Heart & Thoracic Surgery (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- Veterinary Medicine (AREA)
- Immunology (AREA)
- Biochemistry (AREA)
- Analytical Chemistry (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Optics & Photonics (AREA)
- Hematology (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physiology (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Dentistry (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Rheumatology (AREA)
- Physical Education & Sports Medicine (AREA)
- Signal Processing (AREA)
- Psychiatry (AREA)
- Artificial Intelligence (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Radiology & Medical Imaging (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Pharmacology & Pharmacy (AREA)
Abstract
A wearable device includes a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user. First and second light emitting diodes generate corresponding output beams having an initial light intensity and a wavelength between 700-2500 nanometers. A receiver includes spatially separated detectors receiving reflected light from the output beams coupled to analog to digital converters to generate first and second detector signals. The receiver is configured to synchronize to the light emitting diode(s) and to generate an output signal by comparing the first and second detector signals. The measurement device improves signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of the light emitting diode(s).
Description
- This application is a continuation of U.S. application Ser. No. 16/029,611 filed Jul. 8, 2018, which is a continuation of U.S. application Ser. No. 15/888,052 filed Feb. 4, 2018, now U.S. Pat. No. 10,136,819 issued Nov. 27, 2018, which is a continuation of U.S. application Ser. No. 15/212,549 filed Jul. 18, 2016, now U.S. Pat. No. 9,885,698 issued Feb. 6, 2018, which is a continuation of U.S. application Ser. No. 14/650,897 filed Jun. 10, 2015, now U.S. Pat. No. 9,494,567 issued Nov. 15, 2016, which is a U.S. National Phase of PCT/US2013/075700 filed Dec. 17, 2013, which claims the benefit of U.S. provisional application Ser. No. 61/747,472 filed Dec. 31, 2012, the disclosures of which are hereby incorporated in their entirety by reference herein.
- This application is related to U.S. provisional application Ser. No. 61/747,477 filed Dec. 31, 2012; Ser. No. 61/747,481 filed Dec. 31, 2012; Ser. No. 61/747,485 filed Dec. 31, 2012; Ser. No. 61/747,487 filed Dec. 31, 2012; Ser. No. 61/747,492 filed Dec. 31, 2012; Ser. No. 61/747,553 filed Dec. 31, 2012; and Ser. No. 61/754,698 filed Jan. 21, 2013, the disclosures of which are hereby incorporated in their entirety by reference herein.
- This application has a common priority date with International Application PCT/US2013/075736 entitled Short-Wave Infrared Super-Continuum Lasers For Early Detection Of Dental Caries; U.S. application Ser. No. 14/108,995 filed Dec. 17, 2013 entitled Focused Near-Infrared Lasers For Non-Invasive Vasectomy And Other Thermal Coagulation Or Occlusion Procedures; International Application PCT/US2013/075767 entitled Short-Wave Infrared Super-Continuum Lasers For Natural Gas Leak Detection, Exploration, And Other Active Remote Sensing Applications; U.S. application Ser. No. 14/108,986 filed Dec. 17, 2013 entitled Short-Wave Infrared Super-Continuum Lasers For Detecting Counterfeit Or Illicit Drugs And Pharmaceutical Process Control; U.S. application Ser. No. 14/108,974 filed Dec. 17, 2013 entitled Non-Invasive Treatment Of Varicose Veins; and U.S. application Ser. No. 14/109,007 filed Dec. 17, 2013 entitled Near-Infrared Super-Continuum Lasers For Early Detection Of Breast And Other Cancers, the disclosures of which are hereby incorporated in their entirety by reference herein.
- With the growing obesity epidemic, the number of individuals with diabetes is also increasing dramatically. For example, there are over 200 million people who have diabetes. Diabetes control requires monitoring of the glucose level, and most glucose measuring systems available commercially require drawing of blood. Depending on the severity of the diabetes, a patient may have to draw blood and measure glucose four to six times a day. This may be extremely painful and inconvenient for many people. In addition, for some groups, such as soldiers in the battlefield, it may be dangerous to have to measure periodically their glucose level with finger pricks.
- Thus, there is an unmet need for non-invasive glucose monitoring (e.g., monitoring glucose without drawing blood). The challenge has been that a non-invasive system requires adequate sensitivity and selectivity, along with repeatability of the results. Yet, this is a very large market, with an estimated annual market of over $10B in 2011 for self-monitoring of glucose levels.
- One approach to non-invasive monitoring of blood constituents or blood analytes is to use near-infrared spectroscopy, such as absorption spectroscopy or near-infrared diffuse reflection or transmission spectroscopy. Some attempts have been made to use broadband light sources, such as tungsten lamps, to perform the spectroscopy. However, several challenges have arisen in these efforts. First, many other constituents in the blood also have signatures in the near-infrared, so spectroscopy and pattern matching, often called spectral fingerprinting, is required to distinguish the glucose with sufficient confidence. Second, the non-invasive procedures have often transmitted or reflected light through the skin, but skin has many spectral artifacts in the near-infrared that may mask the glucose signatures. Moreover, the skin may have significant water and blood content. These difficulties become particularly complicated when a weak light source is used, such as a lamp. More light intensity can help to increase the signal levels, and, hence, the signal-to-noise ratio.
- As described in this disclosure, by using brighter light sources, such as fiber-based supercontinuum lasers, super-luminescent laser diodes, light-emitting diodes or a number of laser diodes, the near-infrared signal level from blood constituents may be increased. By shining light through the teeth, which have fewer spectral artifacts than skin in the near-infrared, the blood constituents may be measured with less interfering artifacts. Also, by using pattern matching in spectral fingerprinting and various software techniques, the signatures from different constituents in the blood may be identified. Moreover, value-add services may be provided by wirelessly communicating the monitored data to a handheld device such as a smart phone, and then wirelessly communicating the processed data to the cloud for storing, processing, and transmitting to several locations.
- In one embodiment, a smart phone or tablet comprises one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue. An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue. An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, wherein the infrared camera generates data based at least in part on the received light. The infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, and wherein the infrared camera generates additional data based at least in part on the received light. The infrared camera is further configured to: receive light while the one or more laser diodes and the array of laser diodes are off and convert the received light into a first signal; and receive light while at least some of the one or more laser diodes or some of the array of laser diodes are on, and convert the received light into a second signal, the received light including at least a part of the portion of the light from the at least one of the one or more laser diodes reflected from the tissue, or at least a part of the portion of the light from the array of laser diodes reflected from the tissue. The smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using a difference between the first signal and the second signal, and using at least part of the data or at least part of the additional data from the infrared camera. The smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- Embodiments may include a smart phone or tablet comprising one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue. An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue. An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, and wherein the infrared camera generates data based at least in part on the received light. The infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, wherein the infrared camera generates additional data based at least in part on the received light. The smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using at least part of the data or part of the additional data from the infrared camera. The smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- In one embodiment, a smart phone or tablet comprises one or more laser diodes configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A first one or more lenses is configured to receive a portion of the light from the one or more laser diodes and to direct at least some portion of the received light to tissue. An array of laser diodes is configured to be pulsed and to generate light having one or more optical wavelengths, wherein at least a portion of the one or more optical wavelengths is a near-infrared wavelength between 700 nanometers and 2500 nanometers. A second one or more lenses is configured to receive a portion of the light from the array of laser diodes, the array of laser diodes and the second one or more lenses configured to form the light into a plurality of spots and to direct at least some of the spots to tissue, wherein the plurality of spots are also formed at least in part by using an assembly in front of the array of laser diodes. An infrared camera is configured to be synchronized to the at least one of the one or more laser diodes to receive at least a portion of light reflected from the tissue from at least one of the one or more laser diodes, wherein the infrared camera generates data based at least in part on the received light. The infrared camera is further configured to be synchronized to the array of laser diodes to receive light from at least a portion of the plurality of spots reflected from the tissue, wherein the infrared camera generates additional data based at least in part on the received light. The smart phone or tablet is configured to generate a two-dimensional or three-dimensional image using at least part of the data or part of the additional data from the infrared camera. The smart phone or tablet further comprises a wireless receiver, a wireless transmitter, a display, a voice input module, and a speaker.
- For a more complete understanding of the present disclosure, and for further features and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
-
FIG. 1 plots the transmittance versus wavenumber for glucose in the mid-wave and long-wave infrared wavelengths between approximately 2.7 to 12 microns. -
FIG. 2 illustrates measurements of the absorbance of different blood constituents, such as glucose, hemoglobin, and hemoglobin A1c. The measurements are done using an FTIR spectrometer in samples with a 1 mm path length. -
FIG. 3A shows the normalized absorbance of water and glucose (not drawn to scale). Water shows transmission windows between about 1500-1850 nm and 2050-2500 nm. -
FIG. 3B illustrates the absorbance of hemoglobin and oxygenated hemoglobin overlapped with water. -
FIG. 4A shows measured absorbance in different concentrations of glucose solution over the wavelength range of about 2000 to 2400 nm. This data is collected using a SWIR super-continuum laser with the sample path length of about 1.1 mm. -
FIG. 4B illustrates measured absorbance in different concentrations of glucose solution over the wavelength range of about 1550 to 1800 nm. The data is collected using a SWIR super-continuum laser with a sample path length of about 10 mm. -
FIG. 5 illustrates the spectrum for different blood constituents in the wavelength range of about 2 to 2.45 microns (2000 to 2450 nm). -
FIG. 6 shows the transmittance versus wavelength in microns for the ketone 3-hydroxybutyrate. The wavelength range is approximately 2 to 16 microns. -
FIG. 7 illustrates the optical absorbance for ketones as well as some other blood constituents in the wavelength range of about 2100 to 2400 nm. -
FIG. 8A shows the first derivative spectra of ketone and protein at concentrations of 10 g/L (left). In addition, the first derivative spectra of urea, creatinine, and glucose are shown on the right at concentrations of 10 g/L. -
FIG. 8B illustrates the near infrared absorbance for triglyceride. -
FIG. 8C shows the near-infrared reflectance spectrum for cholesterol. -
FIG. 8D illustrates the near-infrared reflectance versus wavelength for various blood constituents, including cholesterol, glucose, albumin, uric acid, and urea. -
FIG. 9 shows a schematic of the human skin. In particular, the dermis may comprise significant amounts of collagen, elastin, lipids, and water. -
FIG. 10 illustrates the absorption coefficients for water (including scattering), adipose, collagen, and elastin. -
FIG. 11 shows the dorsal of the hand, where a differential measurement may be made to at least partially compensate for or subtract out the skin interference. -
FIG. 12 shows the dorsal of the foot, where a differential measurement may be made to at least partially compensate for or subtract out the skin interference. -
FIG. 13A shows an embodiment that may comprise multiple collimated or focused light beams. -
FIG. 13B illustrates a typical human nail tissue structure and the capillary vessels below it. -
FIG. 14 shows the attenuation coefficient for seven nail samples that are allowed to stand in an environment with a humidity level of 14%. These coefficients are measured using an FTIR spectrometer over the near-infrared wavelength range of approximately 1 to 2.5 microns. Below is also included the spectrum of glucose. -
FIG. 15 illustrates the structure of a tooth. -
FIG. 16A shows the attenuation coefficient for dental enamel and water versus wavelength from approximately 600 nm to 2600 nm. -
FIG. 16B illustrates the absorption spectrum of intact enamel and dentine in the wavelength range of approximately 1.2 to 2.4 microns. -
FIG. 17 shows the near infrared spectral reflectance over the wavelength range of approximately 800 nm to 2500 nm from an occlusal tooth surface. The black diamonds correspond to the reflectance from a sound, intact tooth section. The asterisks correspond to a tooth section with an enamel lesion. The circles correspond to a tooth section with a dentine lesion. -
FIG. 18A illustrates a clamp design of a human interface to cap over one or more teeth and perform a non-invasive measurement of blood constituents. -
FIG. 18B shows a mouth guard design of a human interface to perform a non-invasive measurement of blood constituents. -
FIG. 19 illustrates a block diagram or building blocks for constructing high power laser diode assemblies. -
FIG. 20 shows a platform architecture for different wavelength ranges for an all-fiber-integrated, high powered, super-continuum light source. -
FIG. 21 illustrates one embodiment of a short-wave infrared (SWIR) super-continuum (SC) light source. -
FIG. 22 shows the output spectrum from the SWIR SC laser ofFIG. 21 when .about.10 m length of fiber for SC generation is used. This fiber is a single-mode, non-dispersion shifted fiber that is optimized for operation near 1550 nm. -
FIG. 23 illustrates high power SWIR-SC lasers that may generate light between approximately 1.4-1.8 microns (top) or approximately 2-2.5 microns (bottom). -
FIG. 24 schematically shows that the medical measurement device can be part of a personal or body area network that communicates with another device (e.g., smart phone or tablet) that communicates with the cloud. The cloud may in turn communicate information with the user, healthcare providers, or other designated recipients. - As required, detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.
- Various ailments or diseases may require measurement of the concentration of one or more blood constituents. For example, diabetes may require measurement of the blood glucose and HbA1c levels. On the other hand, diseases or disorders characterized by impaired glucose metabolism may require the measurement of ketone bodies in the blood. Examples of impaired glucose metabolism diseases include Alzheimer's, Parkinson's, Huntington's, and Lou Gehrig's or amyotrophic lateral sclerosis (ALS). Techniques related to near-infrared spectroscopy or hyper-spectral imaging may be particularly advantageous for non-invasive monitoring of some of these blood constituents.
- Hyper-spectral images may provide spectral information to identify and distinguish between spectrally similar materials, providing the ability to make proper distinctions among materials with only subtle signature differences. In the SWIR wavelength range, numerous gases, liquids and solids have unique chemical signatures, particularly materials comprising hydro-carbon bonds, O—H bonds, N—H bonds, etc. Therefore, spectroscopy in the SWIR may be attractive for stand-off or remote sensing of materials based on their chemical signature, which may complement other imaging information.
- One embodiment of remote sensing that is used to identify and classify various materials is so-called “hyper-spectral imaging.” Hyper-spectral sensors may collect information as a set of images, where each image represents a range of wavelengths over a spectral band. Hyper-spectral imaging may deal with imaging narrow spectral bands over an approximately continuous spectral range. As an example, in hyper-spectral imaging the sun may be used as the illumination source, and the daytime illumination may comprise direct solar illumination as well as scattered solar (skylight), which is caused by the presence of the atmosphere. However, the sun illumination changes with time of day, clouds or inclement weather may block the sun light, and the sun light is not accessible in the night time. Therefore, it would be advantageous to have a broadband light source covering the SWIR that may be used in place of the sun to identify or classify materials in remote sensing or stand-off detection applications.
- In one embodiment, a SWIR camera or infrared camera system may be used to capture the images. The camera may include one or more lenses on the input, which may be adjustable. The focal plane assemblies may be made from mercury cadmium telluride material (HgCdTe), and the detectors may also include thermo-electric coolers. Alternately, the image sensors may be made from indium gallium arsenide (InGaAs), and CMOS transistors may be connected to each pixel of the InGaAs photodiode array. The camera may interface wirelessly or with a cable (e.g., USB, Ethernet cable, or fiber optics cable) to a computer or tablet or smart phone, where the images may be captured and processed. These are a few examples of infrared cameras, but other SWIR or infrared cameras may be used and are intended to be covered by this disclosure.
- Described herein are just some examples of the beneficial use of near-infrared or SWIR lasers for active remote sensing or hyper-spectral imaging. However, many other spectroscopy and identification procedures can use the near-infrared or SWIR light consistent with this disclosure and are intended to be covered by the disclosure. As one example, the fiber-based super-continuum lasers may have a pulsed output with pulse durations of approximately 0.5-2 nsec and pulse repetition rates of several Megahertz. Therefore, the active remote sensing or hyper-spectral imaging applications may also be combined with LIDAR-type applications. Namely, the distance or time axis can be added to the information based on time-of-flight measurements. For this type of information to be used, the detection system would also have to be time-gated to be able to measure the time difference between the pulses sent and the pulses received. By calculating the round-trip time for the signal, the distance of the object may be judged. In another embodiment, GPS (global positioning system) information may be added, so the active remote sensing or hyper-spectral imagery would also have a location tag on the data. Moreover, the active remote sensing or hyper-spectral imaging information could also be combined with two-dimensional or three-dimensional images to provide a physical picture as well as a chemical composition identification of the materials. These are just some modifications of the active remote sensing or hyper-spectral imaging system described in this disclosure, but other techniques may also be added or combinations of these techniques may be added, and these are also intended to be covered by this disclosure.
- Described herein are just some examples of the beneficial use of near-infrared or SWIR lasers for active remote sensing or hyper-spectral imaging. However, many other spectroscopy and identification procedures can use the near-infrared or SWIR light consistent with this disclosure and are intended to be covered by the disclosure. As one example, the fiber-based super-continuum lasers may have a pulsed output with pulse durations of approximately 0.5-2 nsec and pulse repetition rates of several Megahertz. Therefore, the active remote sensing or hyper-spectral imaging applications may also be combined with LIDAR-type applications. Namely, the distance or time axis can be added to the information based on time-of-flight measurements. For this type of information to be used, the detection system would also have to be time-gated to be able to measure the time difference between the pulses sent and the pulses received. By calculating the round-trip time for the signal, the distance of the object may be judged. In another embodiment, GPS (global positioning system) information may be added, so the active remote sensing or hyper-spectral imagery would also have a location tag on the data. Moreover, the active remote sensing or hyper-spectral imaging information could also be combined with two-dimensional or three-dimensional images to provide a physical picture as well as a chemical composition identification of the materials. These are just some modifications of the active remote sensing or hyper-spectral imaging system described in this disclosure, but other techniques may also be added or combinations of these techniques may be added, and these are also intended to be covered by this disclosure.
- In some instances, it may be desirable to create multiple locations of focused light on the varicose vein. For example, the speed of the treatment may be increased by causing thermal coagulation or occlusion at multiple locations. Multiple collimated or focused light beams may be created in one assembly. In this embodiment, optionally a surface cooling apparatus may be used, where a cooling fluid may be flowed either touching or in close proximity to the skin. Also, in this particular embodiment a cylindrical assembly may optionally be used, where the cylindrical length may be several millimeters in length and defined by a clamp or mount placed on or near the leg. In one embodiment, a window and/or lenslet array is also shown on the cylindrical surface for permitting the light to be incident on the skin and varicose vein at multiple spots. The lenslet array may comprise circular, spherical or cylindrical lenses, depending on the type of spots desired. As before, one advantage of placing the lenslet array in close proximity to the skin and varicose vein may be that a high NA, lens may be used. Also, the input from the lens and/or mirror assembly to the lenslet array may be single large beam, or a plurality of smaller beams. In one embodiment, a plurality of spots may be created by the lenslet array to cause a plurality of locations of thermal coagulation in the varicose vein. Any number of spots may be used and are intended to be covered by this disclosure.
- In a non-limiting example, a plurality of spots may be used, or what might be called a fractionated beam. The fractionated laser beam may be added to the laser delivery assembly or delivery head in a number of ways. In one embodiment, a screen-like spatial filter may be placed in the pathway of the beam to be delivered to the biological tissue. The screen-like spatial filter can have opaque regions to block the light and holes or transparent regions, through which the laser beam may pass to the tissue sample. The ratio of opaque to transparent regions may be varied, depending on the application of the laser. In another embodiment, a lenslet array can be used at or near the output interface where the light emerges. In yet another embodiment, at least a part of the delivery fiber from the infrared laser system to the delivery head may be a bundle of fibers, which may comprise a plurality of fiber cores surrounded by cladding regions. The fiber cores can then correspond to the exposed regions, and the cladding areas can approximate the opaque areas not to be exposed to the laser light. As an example, a bundle of fibers may be excited by at least a part of the laser system output, and then the fiber bundle can be fused together and perhaps pulled down to a desired diameter to expose to the tissue sample near the delivery head. In yet another embodiment, a photonic crystal fiber may be used to create the fractionated laser beam. In one non-limiting example, the photonic crystal fiber can be coupled to at least a part of the laser system output at one end, and the other end can be coupled to the delivery head. In a further example, the fractionated laser beam may be generated by a heavily multi-mode fiber, where the speckle pattern at the output may create the high intensity and low intensity spatial pattern at the output. Although several exemplary techniques are provided for creating a fractionated laser beam, other techniques that can be compatible with optical fibers are also intended to be included by this disclosure.
- Although the output from a fiber laser may be from a single or multi-mode fiber, different spatial spot sizes or spatial profiles may be beneficial for different applications. For example, in some instances it may be desirable to have a series of spots or a fractionated beam with a grid of spots. In one embodiment, a bundle of fibers or a light pipe with a plurality of guiding cores may be used. In another embodiment, one or more fiber cores may be followed by a lenslet array to create a plurality of collimated or focused beams. In yet another embodiment, a delivery light pipe may be followed by a grid-like structure to divide up the beam into a plurality of spots. These are specific examples of beam shaping, and other apparatuses and methods may also be used and are consistent with this disclosure.
- As used throughout this document, the term “couple” and or “coupled” refers to any direct or indirect communication between two or more elements, whether or not those elements are physically connected to one another. As used throughout this disclosure, the term “spectroscopy” means that a tissue or sample is inspected by comparing different features, such as wavelength (or frequency), spatial location, transmission, absorption, reflectivity, scattering, refractive index, or opacity. In one embodiment, “spectroscopy” may mean that the wavelength of the light source is varied, and the transmission, absorption or reflectivity of the tissue or sample is measured as a function of wavelength. In another embodiment, “spectroscopy” may mean that the wavelength dependence of the transmission, absorption or reflectivity is compared between different spatial locations on a tissue or sample. As an illustration, the “spectroscopy” may be performed by varying the wavelength of the light source, or by using a broadband light source and analyzing the signal using a spectrometer, wavemeter, or optical spectrum analyzer.
- As used throughout this document, the term “fiber laser” refers to a laser or oscillator that has as an output light or an optical beam, wherein at least a part of the laser comprises an optical fiber. For instance, the fiber in the “fiber laser” may comprise one of or a combination of a single mode fiber, a multi-mode fiber, a mid-infrared fiber, a photonic crystal fiber, a doped fiber, a gain fiber, or, more generally, an approximately cylindrically shaped waveguide or light-pipe. In one embodiment, the gain fiber may be doped with rare earth material, such as ytterbium, erbium, and/or thulium. In another embodiment, the mid-infrared fiber may comprise one or a combination of fluoride fiber, ZBLAN fiber, chalcogenide fiber, tellurite fiber, or germanium doped fiber. In yet another embodiment, the single mode fiber may include standard single-mode fiber, dispersion shifted fiber, non-zero dispersion shifted fiber, high-nonlinearity fiber, and small core size fibers.
- As used throughout this disclosure, the term “pump laser” refers to a laser or oscillator that has as an output light or an optical beam, wherein the output light or optical beam is coupled to a gain medium to excite the gain medium, which in turn may amplify another input optical signal or beam. In one particular example, the gain medium may be a doped fiber, such as a fiber doped with ytterbium, erbium or thulium. In one embodiment, the “pump laser” may be a fiber laser, a solid state laser, a laser involving a nonlinear crystal, an optical parametric oscillator, a semiconductor laser, or a plurality of semiconductor lasers that may be multiplexed together. In another embodiment, the “pump laser” may be coupled to the gain medium by using a fiber coupler, a dichroic mirror, a multiplexer, a wavelength division multiplexer, a grating, or a fused fiber coupler.
- As used throughout this document, the term “super-continuum” and or “supercontinuum” and or “SC” refers to a broadband light beam or output that comprises a plurality of wavelengths. In a particular example, the plurality of wavelengths may be adjacent to one-another, so that the spectrum of the light beam or output appears as a continuous band when measured with a spectrometer. In one embodiment, the broadband light beam may have a bandwidth of at least 10 nm. In another embodiment, the “super-continuum” may be generated through nonlinear optical interactions in a medium, such as an optical fiber or nonlinear crystal. For example, the “super-continuum” may be generated through one or a combination of nonlinear activities such as four-wave mixing, the Raman effect, modulational instability, and self-phase modulation.
- As used throughout this disclosure, the terms “optical light” and or “optical beam” and or “light beam” refer to photons or light transmitted to a particular location in space. The “optical light” and or “optical beam” and or “light beam” may be modulated or unmodulated. In one embodiment, the “optical light” and or “optical beam” and or “light beam” may originate from a fiber, a fiber laser, a laser, a light emitting diode, a lamp, a pump laser, or a light source. In general, the “near-infrared (NIR)” region of the electromagnetic spectrum covers between approximately 0.7 microns (700 nm) to about 2.5 microns (2500 nm). However, it may also be advantageous to use just the short-wave infrared between approximately 1.4 microns (1400 nm) and about 2.5 microns (2500 nm). One reason for preferring the SWIR over the entire NIR may be to operate in the so-called “eye-safe” window, which corresponds to wavelengths longer than about 1400 nm. Therefore, for the remainder of the disclosure the SWIR will be used for illustrative purposes. However, it should be clear that the discussion that follows could also apply to using the NIR wavelength range, or other wavelength bands.
- One molecule of interest is glucose. The glucose molecule has the chemical formula C6H12O6, so it has a number of hydro-carbon bonds. An example of the infrared transmittance of
glucose 100 is illustrated inFIG. 1 . The vibrational spectroscopy shows that the strongest lines for bending and stretching modes of C—H and O—H bonds lie in the wavelength range of approximately 6-12 microns. However, light sources and detectors are more difficult in the mid-wave infrared and long-wave infrared, and there is also strongly increasing water absorption in the human body beyond about 2.5 microns. Although weaker, there are also nonlinear combinations of stretching and bending modes between about 2 to 2.5 microns, and first overtone of C—H stretching modes between approximately 1.5-1.8 microns. These signatures may fall in valleys of water absorption, permitting non-invasive detection through the body. In addition, there are yet weaker features from the second overtones and higher-order combinations between about 0.8-1.2 microns; in addition to being weaker, these features may also be masked by absorption in the hemoglobin. Hence, the short-wave infrared (SWIR) wavelength range of approximately 1.4 to 2.5 microns may be an attractive window for near-infrared spectroscopy of blood constituents. - As an example, measurements of the
optical absorbance 200 of hemoglobin, glucose and HbA1c have been performed using a Fourier-Transform Infrared Spectrometer—FTIR. AsFIG. 2 shows, in the SWIR wavelength range hemoglobin is nearly flat in spectrum 201 (the noise at the edges is due to the weaker light signal in the measurements). On the other hand, theglucose absorbance 202 has at least five distinct peaks near 1587 nm, 1750 nm, 2120 nm, 2270 nm and 2320 nm. -
FIG. 3A overlaps 300 the normalized absorbance ofglucose 301 with the absorbance of water 302 (not drawn to scale). It may be seen that water has an absorbance feature between approximately 1850 nm and 2050 nm, butwater 302 also has a nice transmission window between approximately 1500-1850 nm and 2050 to 2500 nm. For wavelengths less than about 1100 nm, the absorption ofhemoglobin 351 and oxygenatedhemoglobin 352 inFIG. 3B has a number offeatures 350, which may make it more difficult to measure blood constituents. Also, beyond 2500 nm the water absorption becomes considerably stronger over a wide wavelength range. Therefore, an advantageous window for measuring glucose and other blood constituents may be in the SWIR between 1500 and 1850 nm and 2050 to 2500 nm. These are exemplary wavelength ranges, and other ranges can be used that would still fall within the scope of this disclosure. - One further consideration in choosing the laser wavelength is known as the “eye safe” window for wavelengths longer than about 1400 nm. In particular, wavelengths in the eye safe window may not transmit down to the retina of the eye, and therefore, these wavelengths may be less likely to create permanent eye damage. The near-infrared wavelengths have the potential to be dangerous, because the eye cannot see the wavelengths (as it can in the visible), yet they can penetrate and cause damage to the eye. Even if a practitioner is not looking directly at the laser beam, the practitioner's eyes may receive stray light from a reflection or scattering from some surface. Hence, it can always be a good practice to use eye protection when working around lasers. Since wavelengths longer than about 1400 nm are substantially not transmitted to the retina or substantially absorbed in the retina, this wavelength range is known as the eye safe window. For wavelengths longer than 1400 nm, in general only the cornea of the eye may receive or absorb the light radiation.
- Beyond measuring blood constituents such as glucose using FTIR spectrometers, measurements have also been conducted in another embodiment using super-continuum lasers, which will be described later in this disclosure. In this particular embodiment, some of the exemplary preliminary data for glucose absorbance are illustrated in
FIGS. 4A and 4B . Theoptical spectra 401 inFIG. 4A for different levels of glucose concentration in the wavelength range between 2000 and 2400 nm show the three absorption peaks near 2120 nm (2.12 μm), 2270 nm (2.27 μm) and 2320 nm (2.32 μm). Moreover, theoptical spectra 402 inFIG. 4B for different levels of glucose concentration in the wavelength range between 1500 and 1800 nm show the two broader absorption peaks near 1587 nm and 1750 nm. It should be appreciated that although data measured with FTIR spectrometers or super-continuum lasers have been illustrated, other light sources can also be used to obtain the data, such as super-luminescent laser diodes, light emitting diodes, a plurality of laser diodes, or even bright lamp sources that generate adequate light in the SWIR. - Although glucose has a distinctive signature in the SWIR wavelength range, one problem of non-invasive glucose monitoring is that many other blood constituents also have hydro-carbon bonds. Consequently, there can be interfering signals from other constituents in the blood. As an example,
FIG. 5 illustrates thespectrum 500 for different blood constituents in the wavelength range of 2 to 2.45 microns. Theglucose absorption spectrum 501 can be unique with its three peaks in this wavelength range. However, other blood constituents such astriacetin 502,ascorbate 503,lactate 504,alanine 505,urea 506, andBSA 507 also have spectral features in this wavelength range. To distinguish theglucose 501 from these overlapping spectra, it may be advantageous to have information at multiple wavelengths. In addition, it may be advantageous to use pattern matching algorithms and other software and mathematical methods to identify the blood constituents of interest. In one embodiment, the spectrum may be correlated with a library of known spectra to determine the overlap integrals, and a threshold function may be used to quantify the concentration of different constituents. This is just one way to perform the signal processing, and many other techniques, algorithms, and software may be used and would fall within the scope of this disclosure. - Beyond glucose, there are many other blood constituents that may also be of interest for health or disease monitoring. In another embodiment, it may be desirous to monitor the level of ketone bodies in the blood stream. Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver. Two of the three are used as a source of energy in the heart and brain, while the third is a waste product excreted from the body. In particular, the three endogenous ketone bodies are acetone, acetoacetic acid, and beta-hydroxybutyrate or 3-hydroxybutyrate, and the waste product ketone body is acetone.
- Ketone bodies may be used for energy, where they are transported from the liver to other tissues. The brain may utilize ketone bodies when sufficient glucose is not available for energy. For instance, this may occur during fasting, strenuous exercise, low carbohydrate, ketogenic diet and in neonates. Unlike most other tissues that have additional energy sources such as fatty acids during periods of low blood glucose, the brain cannot break down fatty acids and relies instead on ketones. In one embodiment, these ketone bodies are detected.
- Ketone bodies may also be used for reducing or eliminating symptoms of diseases or disorders characterized by impaired glucose metabolism. For example, diseases associated with reduced neuronal metabolism of glucose include Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's disease), Huntington's disease and epilepsy. In one embodiment, monitoring of alternate sources of ketone bodies that may be administered orally as a dietary supplement or in a nutritional composition to counteract some of the glucose metabolism impairments is performed. However, if ketone bodies supplements are provided, there is also a need to monitor the ketone level in the blood stream. For instance, if elevated levels of ketone bodies are present in the body, this may lead to ketosis; hyperketonemia is also an elevated level of ketone bodies in the blood. In addition, both acetoacetic acid and beta-hydroxybutyric acid are acidic, and, if levels of these ketone bodies are too high, the pH of the blood may drop, resulting in ketoacidosis.
- The general formula for ketones is CnH2n0. In organic chemistry, a ketone is an organic compound with the structure RC(═O)R′, where R and R′ can be a variety of carbon-containing substituents. It features a carbonyl group (C═O) bonded to two other carbon atoms. Because the ketones contain the hydrocarbon bonds, there might be expected to be features in the SWIR, similar in structure to those found for glucose.
- The
infrared spectrum 600 for the ketone 3-hydroxybutyrate is illustrated inFIG. 6 . Just as in glucose, there are significant features in the mid- and long-wave infrared between 6 to 12 microns, but these may be difficult to observe non-invasively. On the other hand, there are some features in the SWIR that may be weaker, but they could potentially be observed non-invasively, perhaps through blood and water. - The
optical spectra 700 for ketones as well as some other blood constituents are exemplified inFIG. 7 in the wavelength range of 2100 nm to 2400 nm. In this embodiment, the absorbance for ketones is 701, while the absorbance for glucose is 702. However, there are also features in this wavelength range for other blood constituents, such asurea 703, albumin orblood protein 704,creatinine 705, andnitrite 706. In this wavelength range of 2100 to 2400 nm, the features forketone 701 seem more spectrally pronounced than even glucose. - Different signal processing techniques can be used to enhance the spectral differences between different constituents. In one embodiment, the first or second derivatives of the spectra may enable better discrimination between substances. The first derivative may help remove any flat offset or background, while the second derivative may help to remove any sloped offset or background. In some instances, the first or second derivative may be applied after curve fitting or smoothing the reflectance, transmittance, or absorbance. For example,
FIG. 8A illustrates the derivative spectra forketone 801 andglucose 802, which can be distinguished from the derivative spectra forprotein 803,urea 804 andcreatinine 805. Based onFIG. 8A , it appears thatketones 801 may have a more pronounced difference than evenglucose 802 in the wavelength range between 2100 and 2400 nm. Therefore, ketone bodies should also be capable of being monitored using a non-invasive optical technique in the SWIR, and a different pattern matching library could be used for glucose and ketones. - Another blood constituent that may be of interest for monitoring of health or diseases is hemoglobin A1c, also known as HbA1c or glycated hemoglobin (glycol-hemoglobin or glycosylated hemoglobin). HbA1c is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. Thus, HbA1c may serve as a marker for average blood glucose levels over the previous months prior to the measurements.
- In one embodiment, when a physician suspects that a patient may be diabetic, the measurement of HbA1c may be one of the first tests that are conducted. An HbA1c level less than approximately 6% may be considered normal. On the other hand, an HbA1c level greater than approximately 6.5% may be considered to be diabetic. In diabetes mellitus, higher amounts of HbA1c indicate poorer control of blood glucose levels. Thus, monitoring the HbA1c in diabetic patients may improve treatment. Current techniques for measuring HbA1c require drawing blood, which may be inconvenient and painful. The point-of-care devices use immunoassay or boronate affinity chromatography, as an example. Thus, there is also an unmet need for non-invasive monitoring of HbA1c.
-
FIG. 2 illustrates the FTIR measurements ofHbA1c absorbance 203 over the wavelength range between 1500 and 2400 nm for a concentration of approximately 1 mg/ml. Whereas the absorbance ofhemoglobin 201 over this wavelength range is approximately flat, theHbA1c absorbance 203 shows broad features and distinct curvature. Although theHbA1c absorbance 203 does not appear to exhibit as pronounced features asglucose 202, the non-invasive SWIR measurement should be able to detect HbA1c with appropriate pattern matching algorithms. Moreover, the spectrum for HbA1c may be further enhanced by using first or second derivative data, as seen for ketones inFIG. 8A . Beyond absorption, reflectance, or transmission spectroscopy, it may also be possible to detect blood constituents such as HbA1c using Raman spectroscopy or surface-enhanced Raman spectroscopy. In general, Raman spectroscopy may require higher optical power levels. - As an illustration, non-invasive measurement of blood constituents such as glucose, ketone bodies, and HbA1c has been discussed thus far. However, other blood constituents can also be measured using similar techniques, and these are also intended to be covered by this disclosure. In other embodiments, blood constituents such as proteins, albumin, urea, creatinine or nitrites could also be measured. For instance, the same type of SWIR optical techniques might be used, but the pattern matching algorithms and software could use different library features or functions for the different constituents.
- In yet another embodiment, the optical techniques described in this disclosure could also be used to measure levels of triglycerides. Triglycerides are bundles of fats that may be found in the blood stream, particularly after ingesting meals. The body manufactures triglycerides from carbohydrates and fatty foods that are eaten. In other words, triglycerides are the body's storage form of fat. Triglycerides are comprised of three fatty acids attached to a glycerol molecule, and measuring the level of triglycerides may be important for diabetics. The triglyceride levels or concentrations in blood may be rated as follows: desirable or normal may be less than 150 mg/dl; borderline high may be 150-199 mg/dl; high may be 200-499 mg/dl; and very high may be 500 mg/dl or greater.
FIG. 8B illustrates one example of the near-infrared absorbance 825 for triglycerides. There are distinct absorbance peaks in the spectrum that should be measurable. The characteristic absorption bands may be assigned as follows: (a) the first overtones of C—H stretching vibrations (1600-1900 nm); (b) the region of second overtones of C—H stretching vibrations (1100-1250 nm); and, (c) two regions (2000-2200 nm and 1350-1500 nm) that comprise bands due to combinations of C—H stretching vibrations and other vibrational modes. - A further example of blood compositions that can be detected or measured using near-infrared light includes cholesterol monitoring. For example,
FIG. 8C shows the near-infrared reflectance spectrum forcholesterol 850 with wavelength in microns (μm). Distinct absorption peaks are observable near 1210 nm (1.21 μm), 1720 nm (1.72 μm), and between 2300-2500 nm (2.3-2.5 μm). Also, there are other features near 1450 nm (1.45 μm) and 2050 nm (2.05 μm). InFIG. 8D the near-infrared reflectances 875 are displayed versus wavelength (nm) for various blood constituents. The spectrum forcholesterol 876 is overlaid withglucose 877,albumin 878,uric acid 879, andurea 880. As may be noted fromFIG. 8D , at about 1720 nm and 2300 nm,cholesterol 876 reaches approximate reflectance peaks, while some of the other analytes are in a more gradual mode. Various signal processing methods may be used to identify and quantify the concentration ofcholesterol 876 and/orglucose 877, or some of the other blood constituents. - As illustrated by
FIGS. 5 and 7 , one of the issues in measuring a particular blood constituent is the interfering and overlapping signal from other blood constituents. The selection of the constituent of interest may be improved using a number of techniques. For example, a higher light level or intensity may improve the signal-to-noise ratio for the measurement. Second, mathematical modeling and signal processing methodologies may help to reduce the interference, such as multivariate techniques, multiple linear regression, and factor-based algorithms, for example. For instance, a number of mathematical approaches include multiple linear regression, partial least squares, and principal component regression (PCR). Also, as illustrated inFIG. 8A , various mathematical derivatives, including the first and second derivatives, may help to accentuate differences between spectra. In addition, by using a wider wavelength range and using more sampling wavelengths may improve the ability to discriminate one signal from another. These are just examples of some of the methods of improving the ability to discriminate between different constituents, but other techniques may also be used and are intended to be covered by this disclosure. - In one embodiment, a SWIR camera or infrared camera system may be used to capture the images. The camera may include one or more lenses on the input, which may be adjustable. The focal plane assemblies may be made from mercury cadmium telluride material (HgCdTe), and the detectors may also include thermo-electric coolers. Alternately, the image sensors may be made from indium gallium arsenide (InGaAs), and CMOS transistors may be connected to each pixel of the InGaAs photodiode array. The camera may interface wirelessly or with a cable (e.g., USB, Ethernet cable, or fiber optics cable) to a computer or tablet or smart phone, where the images may be captured and processed. These are a few examples of infrared cameras, but other SWIR or infrared cameras may be used and are intended to be covered by this disclosure.
- By use of an active illuminator, a number of advantages may be achieved. First, the variations due to sunlight and time-of-day may be factored out. The effects of the weather, such as clouds and rain, might also be reduced. Also, higher signal-to-noise ratios may be achieved. For example, one way to improve the signal-to-noise ratio would be to use modulation and lock-in techniques. In one embodiment, the light source may be modulated, and then the detection system would be synchronized with the light source. In a particular embodiment, the techniques from lock-in detection may be used, where narrow band filtering around the modulation frequency may be used to reject noise outside the modulation frequency. In an alternate embodiment, change detection schemes may be used, where the detection system captures the signal with the light source on and with the light source off. Again, for this system the light source may be modulated. Then, the signal with and without the light source is differenced. This may enable the sun light changes to be subtracted out. In addition, change detection may help to identify objects that change in the field of view. In the following some exemplary detection systems are described.
- Interference from Skin
- Several proposed non-invasive glucose monitoring techniques rely on transmission, absorption, and/or diffuse reflection through the skin to measure blood constituents or blood analytes in veins, arteries, capillaries or in the tissue itself. However, on top of the interference from other blood constituents or analytes, the skin also introduces significant interference. For example, chemical, structural, and physiological variations occur that may produce relatively large and nonlinear changes in the optical properties of the tissue sample. In one embodiment, the near-infrared reflectance or absorbance spectrum may be a complex combination of the tissue scattering properties that result from the concentration and characteristics of a multiplicity of tissue components including water, fat, protein, collagen, elastin, and/or glucose. Moreover, the optical properties of the skin may also change with environmental factors such as humidity, temperature and pressure. Physiological variation may also cause changes in the tissue measurement over time and may vary based on lifestyle, health, aging, etc. The structure and composition of skin may also vary widely among individuals, between different sites within an individual, and over time on the same individual. Thus, the skin introduces a dynamic interference signal that may have a wide variation due to a number of parameters.
-
FIG. 9 shows a schematic cross-section ofhuman skin dermis 903 and thensubcutaneous fat 904 below the dermis. Theepidermis 902, with a thickness of approximately 10-150 microns, may provide a barrier to infection and loss of moisture and other body constituents. Thedermis 903 ranges in thickness from approximately 0.5 mm to 4 mm (averages approximately 1.2 mm over most of the body) and may provide the mechanical strength and elasticity of skin. - In the
dermis 903, water may account for approximately 70% of the volume. The next most abundant constituent in thedermis 903 may becollagen 905, a fibrous protein comprising 70-75% of the dry weight of thedermis 903.Elastin fibers 906, also a protein, may also be plentiful in thedermis 903, although they constitute a smaller portion of the bulk. In addition, thedermis 903 may contain a variety of structures (e.g., sweat glands, hair follicles with adipose richsebaceous glands 907 near their roots, and blood vessels) and other cellular constituents. - Below the
dermis 903 lies thesubcutaneous layer 904 comprising mostly adipose tissue. Thesubcutaneous layer 904 may be by volume approximately 10% water and may be comprised primarily of cells rich in triglycerides or fat. With this complicated structure of theskin - To better understand the interference that the skin introduces when attempting to measure glucose, the absorption coefficient for the various skin constituents should be examined. For example,
FIG. 10 illustrates 1000 the absorption coefficients for water (including scattering) 1001, adipose 1002,collagen 1003 andelastin 1004. Note that the absorption curves forwater 1001 and adipose 1002 are calibrated, whereas the absorption curves forcollagen 1003 andelastin 1004 are in arbitrary units. Also shown are vertical lines demarcating the wavelengths near 1210nm nm 1006. In general, the water absorption increases with increasing wavelength. With the increasing absorption beyond about 2000 nm, it may be difficult to achieve deeper penetration into biological tissue in the infrared wavelengths beyond approximately 2500 nm. - Although the absorption coefficient may be useful for determining the material in which light of a certain infrared wavelength will be absorbed, to determine the penetration depth of the light of a certain wavelength may also require the addition of scattering loss to the curves. For example, the
water curve 1001 includes the scattering loss curve in addition to the water absorption. In particular, the scattering loss can be significantly higher at shorter wavelengths. In one embodiment, near the wavelength of 1720 nm (vertical line 1006 shown inFIG. 10 ), theadipose absorption 1002 can still be higher than the water plusscattering loss 1001. For tissue that contains adipose, collagen and elastin, such as the dermis of the skin, the total absorption can exceed the light energy lost to water absorption and light scattering at 1720 nm. On the other hand, at 1210 nm theadipose absorption 1002 can be considerably lower than the water plusscattering loss 1001, particularly since the scattering loss can be dominant at these shorter wavelengths. - The interference for glucose lines observed through skin may be illustrated by overlaying the glucose lines over the
absorption curves 1000 for the skin constituents. For example,FIG. 2 illustrated that theglucose absorption 202 included features centered around 1587 nm, 1750 nm, 2120 nm, 2270 nm and 2320 nm. OnFIG. 10 vertical lines have been drawn at the glucose line wavelengths of 1587nm nm nm nm nm 1011. In one embodiment, it may be difficult to detect the glucose lines near 1750nm nm nm 1011 due to significant spectral interference from other skin constituents. On the other hand, the glucose line near 1587m 1007 may be more easily detected because it peaks while most of the other skin constituents are sloped downward toward an absorption valley. Moreover, the glucose line near 2120nm 1009 may also be detectable for similar reasons, although adipose may have conflicting behavior due to local absorption minimum and maximum nearby in wavelength. - Thus, beyond the problem of other blood constituents or analytes having overlapping spectral features (e.g.,
FIG. 5 ), it may be difficult to observe glucose spectral signatures through the skin and its constituents of water, adipose, collagen and elastin. One approach to overcoming this difficulty may be to try to measure the blood constituents in veins that are located at relatively shallow distances below the skin. Veins may be more beneficial for the measurement than arteries, since arteries tend to be located at deeper levels below the skin. Also, in one embodiment it may be advantageous to use a differential measurement to subtract out some of the interfering absorption lines from the skin. For example, an instrument head may be designed to place one probe above a region of skin over a blood vein, while a second probe may be placed at a region of the skin without a noticeable blood vein below it. Then, by differencing the signals from the two probes, at least part of the skin interference may be cancelled out. - Two representative embodiments for performing such a differential measurement are illustrated in
FIG. 11 andFIG. 12 . In one embodiment shown inFIG. 11 , the dorsal of thehand 1100 may be used for measuring blood constituents or analytes. The dorsal of thehand 1100 may have regions that havedistinct veins 1101 as well as regions where the veins are not as shallow or pronounced 1102. By stretching the hand and leaning it backwards, theveins 1101 may be accentuated in some cases. A near-infrared diffuse reflectance measurement may be performed by placing oneprobe 1103 above the vein-rich region 1101. To turn this into a differential measurement, asecond probe 1104 may be placed above a region withoutdistinct veins 1102. Then, the outputs from the two probes may be subtracted 1105 to at least partially cancel out the features from the skin. The subtraction may be done preferably in the electrical domain, although it can also be performed in the optical domain or digitally/mathematically using sampled data based on the electrical and/or optical signals. Although one example of using the dorsal of thehand 1100 is shown, many other parts of the hand can be used within the scope of this disclosure. For example, alternate methods may use transmission through the webbing between the thumb and thefingers 1106, or transmission or diffuse reflection through the tips of thefingers 1107. - In another embodiment, the dorsal of the
foot 1200 may be used instead of the hand. One advantage of such a configuration may be that for self-testing by a user, the foot may be easier to position the instrument using both hands. Oneprobe 1203 may be placed over regions where there are moredistinct veins 1201, and a near-infrared diffuse reflectance measurement may be made. For a differential measurement, asecond probe 1204 may be placed over a region with lessprominent veins 1202, and then the two probe signals may be subtracted, either electronically or optically, or may be digitized/sampled and processed mathematically depending on the particular application and implementation. As with the hand, the differential measurements may be intended to compensate for or subtract out (at least in part) the interference from the skin. Since two regions are used in close proximity on the same body part, this may also aid in removing some variability in the skin from environmental effects such as temperature, humidity, or pressure. In addition, it may be advantageous to first treat the skin before the measurement, by perhaps wiping with a cloth or treated cotton ball, applying some sort of cream, or placing an ice cube or chilled bag over the region of interest. - Although two embodiments have been described, many other locations on the body may be used using a single or differential probe within the scope of this disclosure. In yet another embodiment, the wrist may be advantageously used, particularly where a pulse rate is typically monitored. Since the pulse may be easily felt on the wrist, there is underlying the region a distinct blood flow. Other embodiments may use other parts of the body, such as the ear lobes, the tongue, the inner lip, the nails, the eye, or the teeth. Some of these embodiments will be further described below. The ear lobes or the tip of the tongue may be advantageous because they are thinner skin regions, thus permitting transmission rather than diffuse reflection. However, the interference from the skin is still a problem in these embodiments. Other regions such as the inner lip or the bottom of the tongue may be contemplated because distinct veins are observable, but still the interference from the skin may be problematic in these embodiments. The eye may seem as a viable alternative because it is more transparent than skin. However, there are still issues with scattering in the eye. For example, the anterior chamber of the eye (the space between the cornea and the iris) comprises a fluid known as aqueous humor. However, the glucose level in the eye chamber may have a significant temporal lag on changes in the glucose level compared to the blood glucose level.
- In some instances, it may be desirable to create multiple locations of focused light. One way to accomplish this may be to slide the assemblies and/or the light source. In yet another embodiment shown in
FIG. 13A , multiple collimated or focused light beams may be created in oneassembly 1320. In this embodiment, optionally asurface cooling apparatus 1324 may be used, where a cooling fluid may be flowed either touching or in close proximity to theskin 1321. Also, in this particular embodiment a cylindrical assembly may optionally be used, where the cylindrical length may be several millimeters in length and defined by a clamp or mount 1323 placed on or near the leg. Thelight input 1327 may be received from a light source, which may use a fiber or fiber bundles to couple the light to the lens/mirror assembly 1326. A lens and/ormirror assembly 1326 may be used to couple thelight input 1327 to the lenslet array orwindow 1325, either directly or indirectly. The lens and/ormirror assembly 1326 may also be coupled to the clamp or mountassembly 1323. - In the embodiment of
FIG. 13A , a window and/orlenslet array 1325 is also shown on the cylindrical surface for permitting the light to be incident on theskin 1321 and varicose vein 1322 at multiple spots. Thelenslet array 1325 may comprise circular, spherical or cylindrical lenses, depending on the type of spots desired. As before, one advantage of placing thelenslet array 1325 in close proximity to theskin 1321 may be that a high NA lens may be used. Also, the input from the lens and/or mirror assembly to thelenslet array 1325 may be a single large beam, or a plurality of smaller beams. In one embodiment, a plurality of spots may be created by thelenslet array 1325. Although four spots are shown inFIG. 13A , any number of spots may be used and are intended to be covered by this disclosure. - Different combinations of these techniques may be employed, and other techniques may also be used and are intended to be covered by this disclosure. For example, in some instances only focused light may be used, in other instances only surface cooling or cryogenic sprays may be used, and in yet other embodiments a combination of the two may be used. Moreover, the clamps, mounts and holders are shown in simple design for illustrative purposes, but human factors engineering may be used to make these more user friendly or ergonomic design. These and other variations are also intended to be covered by this disclosure.
- The lens and/or mirror assemblies may comprise one or more lenses, microscope objectives, curved or flat mirrors, lens tipped fibers, or some combination of these elements. As an example, the optics such as used in a camera may be employed in this arrangement, provided that the optics are substantially transparent at the light wavelengths being used. Moreover, reflections and losses through the optics may be reduced by applying anti-reflection coatings, and chromatic dispersion may be reduced by using reflective optics rather than refractive optics. Although a particular method of focusing the light has been described, other methods may also be used and are intended to be covered by this disclosure.
- Because of the complexity of the interference from skin in non-invasive glucose monitoring (e.g.,
FIG. 10 ), other parts of the body without skin above blood vessels or capillaries may be alternative candidates for measuring blood constituents. One embodiment may involve transmission or reflection through human nails. As an example,FIG. 13B illustrates a typical humannail tissue structure 1300 and the capillary vessels below it. Thefingernail 1301 is approximately 1 mm thick, and below this resides a layer ofepidermis 1302 with a thickness of approximately 1 mm. Thedermis 1304 is also shown, and within particularly the top about 0.5 mm of dermis are a significant number of capillary vessels. To measure the blood constituents, the light exposed on the top of the fingernail must penetrate about 2-2.5 mm or more, and the reflected light (round trip passage) should be sufficiently strong to measure. In one embodiment, the distance required to penetrate could be reduced by drilling a hole in thefingernail 1301. - In this alternative embodiment using the fingernail, there may still be interference from the nail's spectral features. For example,
FIG. 14 illustrates theattenuation coefficient 1400 for seven nail samples that are allowed to stand in an environment with a humidity level of 14%. These coefficients are measured using an FTIR spectrometer over the near-infrared wavelength range of approximately 1 to 2.5 microns. These spectra are believed to correspond to the spectra of keratin contained in the nail plate. The base lines for the different samples are believed to differ because of the influence of scattering. Several of the absorption peaks observed correspond to peaks of keratin absorption, while other features may appear from the underlying epidermis and dermis. It should also be noted that theattenuation coefficients 1400 also vary considerably depending on humidity level or water content as well as temperature and other environmental factors. Moreover, the attenuation coefficient may also change in the presence of nail polish of various sorts. - Similar to skin, the large variations in attenuation coefficient for fingernails also may interfere with the absorption peaks of glucose. As an example, in
FIG. 14 below the fingernail spectrum is also shown theglucose spectrum 1401 for two different glucose concentrations. Thevertical lines fingernail spectra 1400. As is apparent, the nail has interfering features that may be similar to skin, particularly since both have spectra that vary not only in wavelength but also with environmental factors. In one embodiment, it may be possible to see theglucose peaks - Yet another embodiment may observe the transmittance or reflectance through teeth to measure blood constituents or analytes.
FIG. 15 illustrates an exemplary structure of atooth 1500. Thetooth 1500 has a top layer called thecrown 1501 and below that aroot 1502 that reaches well into thegum 1506 andbone 1508 of the mouth. The exterior of thecrown 1501 is anenamel layer 1503, and below the enamel is a layer ofdentine 1504 that sits atop a layer ofcementum 1507. Below thedentine 1504 is apulp region 1505, which comprises within itblood vessels 1509 andnerves 1510. If the light can penetrate theenamel 1503 anddentine 1504, then the blood flow and blood constituents can be measured through the blood vessels in thedental pulp 1505. While it may be true that the amount of blood flow in thedental pulp 1505 may be less since it comprises capillaries, the smaller blood flow could still be advantageous if there is less interfering spectral features from the tooth. - The transmission, absorption and reflection from teeth has been studied in the near infrared, and, although there are some features, the enamel and dentine appear to be fairly transparent in the near infrared (particularly wavelengths between 1500 and 2500 nm). For example, the absorption or extinction ratio for light transmission has been studied.
FIG. 16A illustrates theattenuation coefficient 1600 for dental enamel 1601 (filled circles) and the absorption coefficient of water 1602 (open circles) versus wavelength. Near-infrared light may penetrate much further without scattering through all the tooth enamel, due to the reduced scattering coefficient in normal enamel. Scattering in enamel may be fairly strong in the visible, but decreases as approximately 1/wavelength3 (i.e., inverse of the wavelength cubed) with increasing wavelength to a value of only 2-3 cm−1 at 1310 nm and 1550 nm in the near infrared. Therefore, enamel may be virtually transparent in the near infrared with optical attenuation 1-2 orders of magnitude less than in the visible range. - As another example,
FIG. 16B illustrates theabsorption spectrum 1650 of intact enamel 1651 (dashed line) and dentine 1652 (solid line) in the wavelength range of approximately 1.2 to 2.4 microns. In the near infrared there are two absorption bands around 1.5 and 2 microns. The band with a peak around 1.57 microns may be attributed to the overtone of valent vibration of water present in both enamel and dentine. In this band, the absorption is greater for dentine than for enamel, which may be related to the large water content in this tissue. In the region of 2 microns, dentine may have two absorption bands, and enamel one. The band with a maximum near 2.1 microns may belong to the overtone of vibration of PO hydroxyapatite groups, which is the main substance of both enamel and dentine. Moreover, the band with a peak near 1.96 microns in dentine may correspond to water absorption (dentine may contain substantially higher water than enamel). - In addition to the absorption coefficient, the reflectance from intact teeth and teeth with dental caries (e.g., cavities) has been studied. In one embodiment,
FIG. 17 shows the near infraredspectral reflectance 1700 over the wavelength range of approximately 800 nm to 2500 nm from an occlusal (e.g., top/bottom)tooth surface 1704. The curve withblack diamonds 1701 corresponds to the reflectance from a sound, intact tooth section. The curve with asterisks * 1702 corresponds to a tooth section with an enamel lesion. The curve withcircles 1703 corresponds to a tooth section with a dentine lesion. Thus, when there is a lesion, more scattering occurs and there may be an increase in the reflected light. - For wavelengths shorter than approximately 1400 nm, the shapes of the spectra remain similar, but the amplitude of the reflection changes with lesions. Between approximately 1400 nm and 2500 nm, an
intact tooth 1701 has low reflectance (e.g., high transmission), and the reflectance appears to be more or less independent of wavelength. On the other hand, in the presence oflesions dentine 1703, more water can accumulate in the area, so there is also increased water absorption. For example, the dips near 1450 nm and 1900 nm correspond to water absorption, and the reflectance dips are particularly pronounced in thedentine lesion 1703. One other benefit of the absorption, transmission or reflectance in the near infrared may be that stains and non-calcified plaque are not visible in this wavelength range, enabling better discrimination of defects, cracks, and demineralized areas. - Compared with the interference from
skin 1000 inFIG. 10 orfingernails 1400 inFIG. 14 , the teeth appear to introduce much less interference for non-invasive monitoring of blood constituents. The few features inFIG. 16B or 17 may be calibrated out of the measurement. Also, using anintact tooth 1701 may further minimize any interfering signals. Furthermore, since the tooth comprises relatively hard tissue, higher power from the light sources in the near infrared may be used without damaging the tissue, such as with skin. - A number of different types of measurements may be used to sample the blood in the dental pulp. The basic feature of the measurements should be that the optical properties are measured as a function of wavelength at a plurality of wavelengths. As further described below, the light source may output a plurality of wavelengths, or a continuous spectrum over a range of wavelengths. In a preferred embodiment, the light source may cover some or all of the wavelength range between approximately 1400 nm and 2500 nm. The signal may be received at a receiver, which may also comprise a spectrometer or filters to discriminate between different wavelengths. The signal may also be received at a camera, which may also comprise filters or a spectrometer. In an alternate embodiment, the spectral discrimination using filters or a spectrometer may be placed after the light source rather than at the receiver. The receiver usually comprises one or more detectors (optical-to-electrical conversion element) and electrical circuitry. The receiver may also be coupled to analog to digital converters, particularly if the signal is to be fed to a digital device.
- Referring to
FIG. 15 , one or morelight sources 1511 may be used for illumination. In one embodiment, a transmission measurement may be performed by directing thelight source output 1511 to the region near the interface between thegum 1506 anddentine 1504. In one embodiment, the light may be directed using a light guide or a fiber optic. The light may then propagate through thedental pulp 1505 to the other side, where the light may be incident on one or more detectors or another light guide to transport the signal to a spectrometer, receiver orcamera 1512. In another embodiment, the light source may be directed to one or more locations near the interface between thegum 1506 and dentine 1504 (in one example, could be from the two sides of the tooth). The transmitted light may then be detected in the occlusal surface above the tooth using a spectrometer, receiver, orcamera 1512. In yet another embodiment, a reflectance measurement may be conducted by directing thelight source output 1511 to, for example, the occlusal surface of the tooth, and then detecting the reflectance at a spectrometer, receiver orcamera 1513. Although a few embodiments for measuring the blood constituents through a tooth are described, other embodiments and techniques may also be used and are intended to be covered by this disclosure. - The human interface for the non-invasive measurement of blood constituents may be of various forms. In one embodiment, a “clamp”
design 1800 may be used cap over one or more teeth, as illustrated inFIG. 18A . The clamp design may be different for different types of teeth, or it may be flexible enough to fit over different types of teeth. For example, different types of teeth include the molars (toward the back of the mouth), the premolars, the canine, and the incisors (toward the front of the mouth). One embodiment of the clamp-type design is illustrated inFIG. 18A for amolar tooth 1808. The C-clamp 1801 may be made of a plastic or rubber material, and it may comprise alight source input 1802 and adetector output 1803 on the front or back of the tooth. - The
light source input 1802 may comprise a light source directly, or it may have light guided to it from an external light source. Also, thelight source input 1802 may comprise a lens system to collimate or focus the light across the tooth. Thedetector output 1803 may comprise a detector directly, or it may have a light guide to transport the signal to an external detector element. Thelight source input 1802 may be coupled electrically or optically through 1804 to alight input 1806. For example, if the light source is external in 1806, then thecoupling element 1804 may be a light guide, such as a fiber optic. Alternately, if the light source is contained in 1802, then thecoupling element 1804 may be electrical wires connecting to a power supply in 1806. Similarly, thedetector output 1803 may be coupled to adetector output unit 1807 with acoupling element 1805, which may be one or more electrical wires or a light guide, such as a fiber optic. This is just one example of a clamp over one or more teeth, but other embodiments may also be used and are intended to be covered by this disclosure. - In yet another embodiment, one or more light source ports and sensor ports may be used in a mouth-guard type design. For example, one embodiment of a
dental mouth guard 1850 is illustrated inFIG. 18B . The structure of themouth guard 1851 may be similar to mouth guards used in sports (e.g., when playing football or boxing) or in dental trays used for applying fluoride treatment, and the mouth guard may be made from plastic or rubber materials, for example. As an example, the mouth guard may have one or more lightsource input ports detector output ports - Similar to the clamp design described above, the
light source inputs light source inputs light source inputs light input 1857. For example, if the light source is external in 1857, then the one ormore coupling elements 1856 may be one or more light guides, such as a fiber optic. Alternately, if the light sources are contained in 1852, 1853, then thecoupling element 1856 may be one or more electrical wires connecting to a power supply in 1857. Similarly, thedetector outputs detector output unit 1859 with one ormore coupling elements 1858, which may be one or more electrical wires or one or more light guides, such as a fiber optic. This is just one example of a mouth guard design covering a plurality of teeth, but other embodiments may also be used and are intended to be covered by this disclosure. For instance, the position of the light source inputs and detector output ports could be exchanged, or some mixture of locations of light source inputs and detector output ports could be used. - Also, if reflectance from the teeth is to be measured, then the light sources and detectors may be on the same side of the tooth. Moreover, it may be advantageous to pulse the light source with a particular pulse width and pulse repetition rate, and then the detection system can measure the pulsed light returned from or transmitted through the tooth. Using a lock-in type technique (e.g., detecting at the same frequency as the pulsed light source and also possibly phase locked to the same signal), the detection system may be able to reject background or spurious signals and increase the signal-to-noise ratio of the measurement.
- Other elements may be added to the human interface designs of
FIG. 18 and are also intended to be covered by this disclosure. For instance, in one embodiment it may be desirable to have replaceable inserts that may be disposable. Particularly in a doctor's office or hospital setting, the same instrument may be used with a plurality of patients. Rather than disinfecting the human interface after each use, it may be preferable to have disposable inserts that can be thrown away after each use. In one embodiment, a thin plastic coating material may enclose the clamp design ofFIG. 18A or mouth guard design ofFIG. 18B . The coating material may be inserted before each use, and then after the measurement is exercised the coating material may be peeled off and replaced. Such a design may save the physician or user considerable time, while at the same time provide the business venture with a recurring cost revenue source. Any coating material or other disposable device may be constructed of a material having suitable optical properties that may be considered during processing of the signals used to detect any anomalies in the teeth. - In general, the near-infrared (NIR) region of the electromagnetic spectrum covers between approximately 0.7 microns (700 nm) to about 2.5 microns (2500 nm). However, it may also be advantageous to use just the short-wave infrared between approximately 1.4 microns (1400 nm) and about 2.5 microns (2500 nm). One reason for preferring the SWIR over the entire NIR may be to operate in the so-called “eye-safe” window, which corresponds to wavelengths longer than about 1400 nm. While the SWIR is used for illustrative purposes, it should be clear that the discussion that follows could also apply to using the NIR wavelength range, or other wavelength bands. There are a number of light sources that may be used in the near infrared. To be more specific, the discussion below will consider light sources operating in the so-called short wave infrared (SWIR), which may cover the wavelength range of approximately 1400 nm to 2500 nm. Other wavelength ranges may also be used for the applications described in this disclosure, so the discussion below is merely provided for exemplary types of light sources. The SWIR wavelength range may be valuable for a number of reasons. First, the SWIR corresponds to a transmission window through water and the atmosphere. For example, 302 in
FIG. 3A and 1602 inFIG. 16A illustrate the water transmission windows. Also, through the atmosphere, wavelengths in the SWIR have similar transmission windows due to water vapor in the atmosphere. Second, the so-called “eye-safe” wavelengths are wavelengths longer than approximately 1400 nm. Third, the SWIR covers the wavelength range for nonlinear combinations of stretching and bending modes as well as the first overtone of C—H stretching modes. Thus, for example, glucose and ketones among other substances may have unique signatures in the SWIR. Moreover, many solids have distinct spectral signatures in the SWIR, so particular solids may be identified using stand-off detection or remote sensing. For instance, many explosives have unique signatures in the SWIR. - Different light sources may be selected for the SWIR based on the needs of the application. Some of the features for selecting a particular light source include power or intensity, wavelength range or bandwidth, spatial or temporal coherence, spatial beam quality for focusing or transmission over long distance, and pulse width or pulse repetition rate. Depending on the application, lamps, light emitting diodes (LEDs), laser diodes (LD's), tunable LD's, super-luminescent laser diodes (SLDs), fiber lasers or super-continuum sources (SC) may be advantageously used. Also, different fibers may be used for transporting the light, such as fused silica fibers, plastic fibers, mid-infrared fibers (e.g., tellurite, chalcogenides, fluorides, ZBLAN, etc), or a hybrid of these fibers.
- Lamps may be used if low power or intensity of light is required in the SWIR, and if an incoherent beam is suitable. In one embodiment, in the SWIR an incandescent lamp that can be used is based on tungsten and halogen, which have an emission wavelength between approximately 500 nm to 2500 nm. For low intensity applications, it may also be possible to use thermal sources, where the SWIR radiation is based on the black body radiation from the hot object. Although the thermal and lamp based sources are broadband and have low intensity fluctuations, it may be difficult to achieve a high signal-to-noise ratio in a non-invasive blood constituent measurement due to the low power levels. Also, the lamp based sources tend to be energy inefficient.
- In another embodiment, LED's can be used that have a higher power level in the SWIR wavelength range. LED's also produce an incoherent beam, but the power level can be higher than a lamp and with higher energy efficiency. Also, the LED output may more easily be modulated, and the LED provides the option of continuous wave or pulsed mode of operation. LED's are solid state components that emit a wavelength band that is of moderate width, typically between about 20 nm to 40 nm. There are also so-called super-luminescent LEDs that may even emit over a much wider wavelength range. In another embodiment, a wide band light source may be constructed by combining different LEDs that emit in different wavelength bands, some of which could preferably overlap in spectrum. One advantage of LEDs as well as other solid state components is the compact size that they may be packaged into.
- In yet another embodiment, various types of laser diodes may be used in the SWIR wavelength range. Just as LEDs may be higher in power but narrower in wavelength emission than lamps and thermal sources, the LDs may be yet higher in power but yet narrower in wavelength emission than LEDs. Different kinds of LDs may be used, including Fabry-Perot LDs, distributed feedback (DFB) LDs, distributed Bragg reflector (DBR) LDs. Since the LDs have relatively narrow wavelength range (typically under 10 nm), in one embodiment a plurality of LDs may be used that are at different wavelengths in the SWIR. For example, in a preferred embodiment for non-invasive glucose monitoring, it may be advantageous to use LDs having emission spectra near some or all of the glucose spectral peaks (e.g., near 1587 nm, 1750 nm, 2120 nm, 2270 nm, and 2320 nm). The various LDs may be spatially multiplexed, polarization multiplexed, wavelength multiplexed, or a combination of these multiplexing methods. Also, the LDs may be fiber pig-tailed or have one or more lenses on the output to collimate or focus the light. Another advantage of LDs is that they may be packaged compactly and may have a spatially coherent beam output. Moreover, tunable LDs that can tune over a range of wavelengths are also available. The tuning may be done by varying the temperature, or electrical current may be used in particular structures, such as distributed Bragg reflector LDs. In another embodiment, external cavity LDs may be used that have a tuning element, such as a fiber grating or a bulk grating, in the external cavity.
- In another embodiment, super-luminescent laser diodes may provide higher power as well as broad bandwidth. An SLD is typically an edge emitting semiconductor light source based on super-luminescence (e.g., this could be amplified spontaneous emission). SLDs combine the higher power and brightness of LDs with the low coherence of conventional LEDs, and the emission band for SLD's may be 5 to 100 nm wide, preferably in the 60 to 100 nm range. Although currently SLDs are commercially available in the wavelength range of approximately 400 nm to 1700 nm, SLDs could and may in the future be made to cover a broader region of the SWIR.
- In yet another embodiment, high power LDs for either direct excitation or to pump fiber lasers and SC light sources may be constructed using one or more laser diode bar stacks. As an example,
FIG. 19 shows an example of the block diagram 1900 or building blocks for constructing the high power LDs. In this embodiment, one or morediode bar stacks 1901 may be used, where the diode bar stack may be an array of several single emitter LDs. Since the fast axis (e.g., vertical direction) may be nearly diffraction limited while the slow-axis (e.g., horizontal axis) may be far from diffraction limited,different collimators 1902 may be used for the two axes. - Then, the brightness may be increased by spatially combining the beams from
multiple stacks 1903. The combiner may include spatial interleaving, it may include wavelength multiplexing, or it may involve a combination of the two. Different spatial interleaving schemes may be used, such as using an array of prisms or mirrors with spacers to bend one array of beams into the beam path of the other. In another embodiment, segmented mirrors with alternate high-reflection and anti-reflection coatings may be used. Moreover, the brightness may be increased by polarization beam combining 1904 the two orthogonal polarizations, such as by using a polarization beam splitter. In one embodiment, the output may then be focused or coupled into a large diameter core fiber. As an example, typical dimensions for the large diameter core fiber range from approximately 100 microns in diameter to 400 microns or more. Alternatively or in addition, a custombeam shaping module 1905 may be used, depending on the particular application. For example, the output of the high power LD may be used directly 1906, or it may be fiber coupled 1907 to combine, integrate, or transport the high power LD energy. These high power LDs may grow in importance because the LD powers can rapidly scale up. For example, instead of the power being limited by the power available from a single emitter, the power may increase in multiples depending on the number of diodes multiplexed and the size of the large diameter fiber. AlthoughFIG. 19 is shown as one embodiment, some or all of the elements may be used in a high power LD, or additional elements may also be used. - Each of the light sources described above have particular strengths, but they also may have limitations. For example, there is typically a trade-off between wavelength range and power output. Also, sources such as lamps, thermal sources, and LEDs produce incoherent beams that may be difficult to focus to a small area and may have difficulty propagating for long distances. An alternative source that may overcome some of these limitations is an SC light source. Some of the advantages of the SC source may include high power and intensity, wide bandwidth, spatially coherent beam that can propagate nearly transform limited over long distances, and easy compatibility with fiber delivery.
- Supercontinuum lasers may combine the broadband attributes of lamps with the spatial coherence and high brightness of lasers. By exploiting a modulational instability initiated supercontinuum (SC) mechanism, an all-fiber-integrated SC laser with no moving parts may be built using commercial-off-the-shelf (COTS) components. Moreover, the fiber laser architecture may be a platform where SC in the visible, near-infrared/SWIR, or mid-IR can be generated by appropriate selection of the amplifier technology and the SC generation fiber. But until now, SC lasers were used primarily in laboratory settings since typically large, table-top, mode-locked lasers were used to pump nonlinear media such as optical fibers to generate SC light. However, those large pump lasers may now be replaced with diode lasers and fiber amplifiers that gained maturity in the telecommunications industry.
- In one embodiment, an all-fiber-integrated, high-powered SC
light source 2000 may be elegant for its simplicity (FIG. 20 ). The light may be first generated from aseed laser diode 2001. For example, theseed LD 2001 may be a distributed feedback laser diode with a wavelength near 1542 or 1550 nm, with approximately 0.5-2.0 ns pulsed output, and with a pulse repetition rate between a kilohertz to about 100 MHz or more. The output from the seed laser diode may then be amplified in a multiple-stage fiber amplifier 2002 comprising one or more gain fiber segments. In one embodiment, thefirst stage pre-amplifier 2003 may be designed for optimal noise performance. For example, thepre-amplifier 2003 may be a standard erbium-doped fiber amplifier or an erbium/ytterbium doped cladding pumped fiber amplifier. Betweenamplifier stages pass filters 2004 to block amplified spontaneous emission andisolators 2005 to prevent spurious reflections. Then, thepower amplifier stage 2006 may use a cladding-pumped fiber amplifier that may be optimized to minimize nonlinear distortion. Thepower amplifier fiber 2006 may also be an erbium-doped fiber amplifier, if only low or moderate power levels are to be generated. - The
SC generation 2007 may occur in the relatively short lengths of fiber that follow the pump laser. In one exemplary embodiment, the SC fiber length may range from a few millimeters to 100 m or more. In one embodiment, the SC generation may occur in afirst fiber 2008 where the modulational-instability initiated pulse break-up primarily occurs, followed by asecond fiber 2009 where the SC generation and spectral broadening primarily occurs. - In one embodiment, one or two meters of standard single-mode fiber (SMF) after the power amplifier stage may be followed by several meters of SC generation fiber. For this example, in the SMF the peak power may be several kilowatts and the pump light may fall in the anomalous group-velocity dispersion regime—often called the soliton regime. For high peak powers in the dispersion regime, the nanosecond pulses may be unstable due to a phenomenon known as modulational instability, which is basically parametric amplification in which the fiber nonlinearity helps to phase match the pulses. As a consequence, the nanosecond pump pulses may be broken into many shorter pulses as the modulational instability tries to form soliton pulses from the quasi-continuous-wave background. Although the laser diode and amplification process starts with approximately nanosecond-long pulses, modulational instability in the short length of SMF fiber may form approximately 0.5 ps to several-picosecond-long pulses with high intensity. Thus, the few meters of SMF fiber may result in an output similar to that produced by mode-locked lasers, except in a much simpler and cost-effective manner.
- The short pulses created through modulational instability may then be coupled into a nonlinear fiber for SC generation. The nonlinear mechanisms leading to broadband SC may include four-wave mixing or self-phase modulation along with the optical Raman effect. Since the Raman effect is self-phase-matched and shifts light to longer wavelengths by emission of optical photons, the SC may spread to longer wavelengths very efficiently. The short-wavelength edge may arise from four-wave mixing, and often times the short wavelength edge may be limited by increasing group-velocity dispersion in the fiber. In many instances, if the particular fiber used has sufficient peak power and SC fiber length, the SC generation process may fill the long-wavelength edge up to the transmission window.
- Mature fiber amplifiers for the
power amplifier stage 2006 include ytterbium-doped fibers (near 1060 nm), erbium-doped fibers (near 1550 nm), erbium/ytterbium-doped fibers (near 1550 nm), or thulium-doped fibers (near 2000 nm). In various embodiments, candidates forSC fiber 2009 include fused silica fibers (for generating SC between 0.8-2.7 μm), mid-IR fibers such as fluorides, chalcogenides, or tellurites (for generating SC out to 4.5 μm or longer), photonic crystal fibers (for generating SC between 0.4 and 1.7 μm), or combinations of these fibers. Therefore, by selecting the appropriate fiber-amplifier doping for 2006 andnonlinear fiber 2009, SC may be generated in the visible, near-IR/SWIR, or mid-IR wavelength region. - The
configuration 2000 ofFIG. 20 is just one particular example, and other configurations can be used and are intended to be covered by this disclosure. For example, further gain stages may be used, and different types of lossy elements or fiber taps may be used between the amplifier stages. In another embodiment, the SC generation may occur partially in the amplifier fiber and in the pig-tails from the pump combiner or other elements. In yet another embodiment, polarization maintaining fibers may be used, and a polarizer may also be used to enhance the polarization contrast between amplifier stages. Also, not discussed in detail are many accessories that may accompany this set-up, such as driver electronics, pump laser diodes, safety shut-offs, and thermal management and packaging. - One example of an SC laser that operates in the SWIR used in one embodiment is illustrated in
FIG. 21 . ThisSWIR SC source 2100 produces an output of up to approximately 5 W over a spectral range of about 1.5 to 2.4 microns, and this particular laser is made out of polarization maintaining components. Theseed laser 2101 is a distributed feedback (DFB) laser operating near 1542 nm producing approximately 0.5 nanosecond (ns) pulses at an about 8 MHz repetition rate. Thepre-amplifier 2102 is forward pumped and uses about 2 m length of erbium/ytterbium cladding pumped fiber 2103 (often also called dual-core fiber) with an inner core diameter of 12 microns and outer core diameter of 130 microns. Thepre-amplifier gain fiber 2103 is pumped using a 10 W 940nm laser diode 2105 that is coupled in using afiber combiner 2104. - In this particular 5 W unit, the mid-stage between
amplifier stages isolator 2107, a band-pass filter 2108, apolarizer 2109 and afiber tap 2110. Thepower amplifier 2106 uses a 4 m length of the 12/130 micron erbium/ytterbium dopedfiber 2111 that is counter-propagating pumped using one or more 30 W 940nm laser diodes 2112 coupled in through acombiner 2113. An approximately 1-2 meter length of the combiner pig-tail helps to initiate the SC process, and then a length of PM-1550 fiber 2115 (polarization maintaining, single-mode, fused silica fiber optimized for 1550 nm) is spliced 2114 to the combiner output. - If an output fiber of about 10 m in length is used, then the resulting
output spectrum 2200 is shown inFIG. 22 . The details of theoutput spectrum 2200 depend on the peak power into the fiber, the fiber length, and properties of the fiber such as length and core size, as well as the zero dispersion wavelength and the dispersion properties. For example, if a shorter length of fiber is used, then the spectrum actually reaches to longer wavelengths (e.g., a 2 m length of SC fiber broadens the spectrum to −2500 nm). Also, if extra-dry fibers are used with less O—H content, then the wavelength edge may also reach to a longer wavelength. To generate more spectrum toward the shorter wavelengths, the pump wavelength (in this case .about.1542 nm) should be close to the zero dispersion wavelength in the fiber. For example, by using a dispersion shifted fiber or so-called non-zero dispersion shifted fiber, the short wavelength edge may shift to shorter wavelengths. - Although one particular example of a 5 W SWIR-SC has been described, different components, different fibers, and different configurations may also be used consistent with this disclosure. For instance, another embodiment of the
similar configuration 2100 inFIG. 21 may be used to generate high powered SC between approximately 1060 and 1800 nm. For this embodiment, theseed laser 2101 may be a 1064 nm distributed feedback (DFB) laser diode, thepre-amplifier gain fiber 2103 may be a ytterbium-doped fiber amplifier with 10/125 microns dimensions, and thepump laser 2105 may be a 10 W 915 nm laser diode. In the mid-stage, a mode field adapter may be included in addition to theisolator 2107,band pass filter 2108, polarizer 2109 andtap 2110. Thegain fiber 2111 in the power amplifier may be a 20 m length of ytterbium-doped fiber with 25/400 microns dimension for example. Thepump 2112 for the power amplifier may be up to six pump diodes providing 30 W each near 915 nm, for example. For this much pump power, the output power in the SC may be as high as 50 W or more. - In another embodiment, it may be desirous to generate high power SWIR SC over 1.4-1.8 microns and separately 2-2.5 microns (the window between 1.8 and 2 microns may be less important due to the strong water and atmospheric absorption). For example, the top SC source of
FIG. 23 can lead to bandwidths ranging from about 1400 nm to 1800 nm or broader, while the lower SC source ofFIG. 23 can lead to bandwidths ranging from about 1900 nm to 2500 nm or broader. Since these wavelength ranges are shorter than about 2500 nm, the SC fiber can be based on fused silica fiber. Exemplary SC fibers include standard single-mode fiber SMF, high-nonlinearity fiber, high-NA fiber, dispersion shifted fiber, dispersion compensating fiber, and photonic crystal fibers. Non-fused-silica fibers can also be used for SC generation, including chalcogenides, fluorides, ZBLAN, tellurites, and germanium oxide fibers. - In one embodiment, the top of
FIG. 23 illustrates a block diagram for anSC source 2300 capable of generating light between approximately 1400 and 1800 nm or broader. As an example, a pump fiber laser similar toFIG. 21 can be used as the input to aSC fiber 2309. Theseed laser diode 2301 can comprise a DFB laser that generates, for example, several milliwatts of power around 1542 or 1553 nm. Thefiber pre-amplifier 2302 can comprise an erbium-doped fiber amplifier or an erbium/ytterbium doped double clad fiber. In this example amid-stage amplifier 2303 can be used, which can comprise an erbium/ytterbium doped double-clad fiber. Abandpass filter 2305 andisolator 2306 may be used between the pre-amplifier 2302 andmid-stage amplifier 2303. Thepower amplifier stage 2304 can comprise a larger core size erbium/ytterbium doped double-clad fiber, and anotherbandpass filter 2307 andisolator 2308 can be used before thepower amplifier 2304. The output of the power amplifier can be coupled to theSC fiber 2309 to generate the SC output 2310. This is just one exemplary configuration for an SC source, and other configurations or elements may be used consistent with this disclosure. - In yet another embodiment, the bottom of
FIG. 23 illustrates a block diagram for anSC source 2350 capable of generating light between approximately 1900 and 2500 nm or broader. As an example, theseed laser diode 2351 can comprise a DFB or DBR laser that generates, for example, several milliwatts of power around 1542 or 1553 nm. Thefiber pre-amplifier 2352 can comprise an erbium-doped fiber amplifier or an erbium/ytterbium doped double-clad fiber. In this example amid-stage amplifier 2353 can be used, which can comprise an erbium/ytterbium doped double-clad fiber. Abandpass filter 2355 andisolator 2356 may be used between the pre-amplifier 2352 andmid-stage amplifier 2353. Thepower amplifier stage 2354 can comprise a thulium doped double-clad fiber, and anotherisolator 2357 can be used before thepower amplifier 2354. Note that the output of themid-stage amplifier 2353 can be approximately near 1550 nm, while the thulium-dopedfiber amplifier 2354 can amplify wavelengths longer than approximately 1900 nm and out to about 2100 nm. Therefore, for this configuration wavelength shifting may be required between 2353 and 2354. In one embodiment, the wavelength shifting can be accomplished using a length of standard single-mode fiber 2358, which can have a length between approximately 5 and 50 meters, for example. The output of thepower amplifier 2354 can be coupled to theSC fiber 2359 to generate theSC output 2360. This is just one exemplary configuration for an SC source, and other configurations or elements can be used consistent with this disclosure. For example, the various amplifier stages can comprise different amplifier types, such as erbium doped fibers, ytterbium doped fibers, erbium/ytterbium co-doped fibers and thulium doped fibers. One advantage of the SC lasers illustrated inFIGS. 20-23 are that they may use all-fiber components, so that the SC laser can be all-fiber, monolithically integrated with no moving parts. The all-integrated configuration can consequently be robust and reliable. -
FIGS. 20-23 are examples of SC light sources that may be advantageously used for SWIR light generation in various medical diagnostic and therapeutic applications. However, many other versions of the SC light sources may also be made that are intended to also be covered by this disclosure. For example, the SC generation fiber could be pumped by a mode-locked laser, a gain-switched semiconductor laser, an optically pumped semiconductor laser, a solid state laser, other fiber lasers, or a combination of these types of lasers. Also, rather than using a fiber for SC generation, either a liquid or a gas cell might be used as the nonlinear medium in which the spectrum is to be broadened. - Even within the all-fiber versions illustrated such as in
FIG. 21 , different configurations could be used consistent with the disclosure. In an alternate embodiment, it may be desirous to have a lower cost version of the SWIR SC laser ofFIG. 21 . One way to lower the cost could be to use a single stage of optical amplification, rather than two stages, which may be feasible if lower output power is required or the gain fiber is optimized. For example, thepre-amplifier stage 2102 might be removed, along with at least some of the mid-stage elements. In yet another embodiment, the gain fiber could be double passed to emulate a two stage amplifier. In this example, thepre-amplifier stage 2102 might be removed, and perhaps also some of the mid-stage elements. A mirror or fiber grating reflector could be placed after thepower amplifier stage 2106 that may preferentially reflect light near the wavelength of theseed laser 2101. If the mirror or fiber grating reflector can transmit the pump light near 940 nm, then this could also be used instead of thepump combiner 2113 to bring in thepump light 2112. TheSC fiber 2115 could be placed between theseed laser 2101 and the power amplifier stage 2106 (SC is only generated after the second pass through the amplifier, since the power level may be sufficiently high at that time). In addition, an output coupler may be placed between theseed laser diode 2101 and the SC fiber, which now may be in front of thepower amplifier 2106. In a particular embodiment, the output coupler could be a power coupler or divider, a dichroic coupler (e.g., passing seed laser wavelength but outputting the SC wavelengths), or a wavelength division multiplexer coupler. This is just one further example, but a myriad of other combinations of components and architectures could also be used for SC light sources to generate SWIR light that are intended to be covered by this disclosure. - The non-invasive blood constituent or analytes measurement device may also benefit from communicating the data output to the “cloud” (e.g., data servers and processors in the web remotely connected) via wired and/or wireless communication strategies. The non-invasive devices may be part of a series of biosensors applied to the patient, and collectively these devices form what might be called a body area network or a personal area network. The biosensors and non-invasive devices may communicate to a smart phone, tablet, personal data assistant, computer, and/or other microprocessor-based device, which may in turn wirelessly or over wire and/or fiber optically transmit some or all of the signal or processed data to the internet or cloud. The cloud or internet may in turn send the data to doctors or health care providers as well as the patients themselves. Thus, it may be possible to have a panoramic, high-definition, relatively comprehensive view of a patient that doctors can use to assess and manage disease, and that patients can use to help maintain their health and direct their own care.
- In a
particular embodiment 2400, the physiological measurement device or non-invasive bloodconstituent measurement device 2401 may comprise atransmitter 2403 to communicate over afirst communication link 2404 in the body area network or personal area network to a receiver in a smart phone, tablet cell phone, PDA, orcomputer 2405. For themeasurement device 2401, it may also be advantageous to have aprocessor 2402 to process some of the physiological data, since with processing the amount of data to transmit may be less (hence, more energy efficient). Thefirst communication link 2404 may operate through the use of one of many wireless technologies such as Bluetooth, Zigbee, WiFi, IrDA (infrared data association), wireless USB, or Z-wave, to name a few. Alternatively, thecommunication link 2404 may occur in the wireless medical band between 2360 and 2390 MHz, which the FCC allocated for medical body area network devices, or in other designated medical device or WMTS bands. These are examples of devices that can be used in the body area network and surroundings, but other devices could also be used and are included in the scope of this disclosure. - The
personal device 2405 may store, process, display, and transmit some of the data from themeasurement device 2401. Thedevice 2405 may comprise a receiver, transmitter, display, voice control and speakers, and one or more control buttons or knobs and a touch screen. Examples of thedevice 2405 include smart phones such as the Apple iPhones® or phones operating on the Android or Microsoft systems. In one embodiment, thedevice 2405 may have an application, software program, or firmware to receive and process the data from themeasurement device 2401. Thedevice 2405 may then transmit some or all of the data or the processed data over asecond communication link 2406 to the internet or “cloud” 2407. Thesecond communication link 2406 may advantageously comprise at least one segment of a wireless transmission link, which may operate using WiFi or the cellular network. Thesecond communication link 2406 may additionally comprise lengths of fiber optic and/or communication over copper wires or cables. - The internet or
cloud 2407 may add value to themeasurement device 2401 by providing services that augment the physiological data collected. In a particular embodiment, some of the functions performed by the cloud include: (a) receive at least a fraction of the data from thedevice 2405; (b) buffer or store the data received; (c) process the data using software stored on the cloud; (d) store the resulting processed data; and (e) transmit some or all of the data either upon request or based on an alarm. As an example, the data or processed data may be transmitted 2408 back to the originator (e.g., patient or user), it may be transmitted 2409 to a health care provider or doctor, or it may be transmitted 2410 to other designated recipients. - The
cloud 2407 may provide a number of value-add services. For example, the cloud application may store and process the physiological data for future reference or during a visit with the healthcare provider. If a patient has some sort of medical mishap or emergency, the physician can obtain the history of the physiological parameters over a specified period of time. In another embodiment, if the physiological parameters fall out of acceptable range, alarms may be delivered to theuser 2408, thehealthcare provider 2409, or other designatedrecipients 2410. These are just some of the features that may be offered, but many others may be possible and are intended to be covered by this disclosure. As an example, thedevice 2405 may also have a GPS sensor, so thecloud 2407 may be able to provide time, data and position along with the physiological parameters. Thus, if there is a medical emergency, thecloud 2407 could provide the location of the patient to thehealthcare provider 2409 or other designatedrecipients 2410. Moreover, the digitized data in thecloud 2407 may help to move toward what is often called “personalized medicine.” Based on the physiological parameter data history, medication or medical therapies may be prescribed that are customized to the particular patient. - Beyond the above benefits, the
cloud application 2407 and application on thedevice 2405 may also have financial value for companies developingmeasurement devices 2401 such as a non-invasive blood constituent monitor. In the case of glucose monitors, the companies make the majority of their revenue on the measurement strips. However, with a non-invasive monitor, there is no need for strips, so there is less of an opportunity for recurring costs (e.g., the razor/razor blade model does not work for non-invasive devices). On the other hand, people may be willing to pay a periodic fee for the value-add services provided on thecloud 2407. Diabetic patients, for example, would probably be willing to pay a periodic fee for monitoring their glucose levels, storing the history of the glucose levels, and having alarm warnings when the glucose level falls out of range. Similarly, patients taking ketone bodies supplement for treatment of disorders characterized by impaired glucose metabolism (e.g., Alzheimer's, Parkinson's, Huntington's or ALS) may need to monitor their ketone bodies level. These patients would also probably be willing to pay a periodic fee for the value-add services provided on thecloud 2407. Thus, by leveraging the advances in wireless connectivity and the widespread use of handheld devices such as smart phones that can wirelessly connect to the cloud, businesses can build a recurring cost business model even using non-invasive measurement devices. - Described herein are just some examples of the beneficial use of near-infrared or SWIR lasers for non-invasive monitoring of glucose, ketones, HbA1c and other blood constituents. However, many other medical procedures can use the near-infrared or SWIR light consistent with this disclosure and are intended to be covered by the disclosure.
- Although the present disclosure has been described in several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present disclosure encompass such changes, variations, alterations, transformations, and modifications as falling within the spirit and scope of the appended claims.
- While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the disclosure. While various embodiments may have been described as providing advantages or being preferred over other embodiments with respect to one or more desired characteristics, as one skilled in the art is aware, one or more characteristics may be compromised to achieve desired system attributes, which depend on the specific application and implementation. These attributes include, but are not limited to: cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. The embodiments described herein that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.
Claims (21)
1.-20. (canceled)
21. A wearable device, comprising:
a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user, comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first output optical beam, the first output optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second output optical beam, the second output optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers;
the measurement device further comprising a receiver, the receiver having a first detector and a second detector, the first and second detectors being spatially separated, the first detector configured to receive at least a first reflected portion of the first output optical beam, the second detector configured to receive at least a first reflected portion of the second output optical beam;
one or more analog to digital converters coupled to the spatially separated detectors and configured to generate a first detector signal representing at least in part the first reflected portion of the first output optical beam and to generate a second detector signal representing at least in part the first reflected portion of the second output optical beam, and wherein the receiver is configured to generate an output signal at least in part by comparing the first detector signal and the second detector signal;
the measurement device configured to improve signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
wherein the measurement of the physiological parameter is at least in part a non-invasive measurement on blood; and
wherein the receiver is configured to synchronize to at least one of the first and second light emitting diodes.
22. The wearable device of claim 21 wherein one of the spatially separated detectors is located a first distance from the first light emitting diode and a different distance from the second light emitting diode such that the receiver can receive a first reflected portion of the first output optical beam and a first reflected portion of the second output optical beam, and wherein the receiver is configured to generate a detector output signal at least in part by comparing the received first reflected portion of the first output optical beam and the received first reflected portion of the second output optical beam.
23. The wearable device of claim 22 , wherein the receiver is further configured to:
generate a first receiver signal from light detected while the first and second light emitting diodes are off, and
generate a second receiver signal from light detected while at least one of the first and second light emitting diodes is on including at least a portion of the first reflected portion of the first output optical beam; and
wherein the measurement device is configured to further improve the signal-to-noise ratio of the output signal by differencing the first receiver signal and the second receiver signal.
24. The wearable device of claim 23 , wherein the measurement device is configured to operate at least one of the first light emitting diode and the second light emitting diode in a pulsed mode having a pulse repetition rate, and wherein the receiver is configured to synchronize with the pulsed mode repetition rate of the at least one of the first light emitting diode and the second light emitting diode.
25. The wearable device of claim 24 , wherein the wearable device is configured to communicate with a smart phone or tablet, the smart phone or tablet comprising a wireless receiver, a wireless transmitter, a display, a voice input module, a speaker, and a touch screen, the smart phone or tablet configured to receive and to process at least a portion of the output signal, wherein the smart phone or tablet is configured to store the processed portion of the output signal and to transmit at least a portion of the stored output signal as a transmitted signal over a wireless transmission link to a remote device;
wherein the remote device is configured to receive over the wireless transmission link at least part of the transmitted signal as a received signal, to process the received signal to generate processed data, and to store the processed data, and wherein the remote device is capable of retrieving a history of at least a portion of the processed data; and
wherein the remote device is further configured to transmit at least a portion of the processed data to one or more other locations, wherein the one or more other locations is selected from the group consisting of the smart phone or tablet, a doctor, a healthcare provider, a cloud-based server and one or more designated recipients.
26. The wearable device of claim 25 , wherein the measurement device further comprises a reflective surface positioned to receive and redirect toward the spatially separated detectors at least some of the first output optical beam as a second reflected portion of the first output optical beam, and
wherein the at least one near-infrared wavelength of the first light emitting diode is between 900 nanometers and 1150 nanometers.
27. The wearable device of claim 21 wherein at least one of the first light emitting diode and the second light emitting diode is configured to operate in a continuous wave mode of operation.
28. A wearable device, comprising:
a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first optical beam, the first optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second optical beam, the second optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers;
the measurement device configured to output at least a portion of the first optical beam as a first output optical beam, and to output at least a portion of the second optical beam as a second output optical beam;
the measurement device further comprising a receiver having one or more detectors, wherein one of the one or more detectors is located a first distance from the first light emitting diode and a different distance from the second light emitting diode to be capable of receiving at least a first reflected portion of the first output optical beam and generating a first detector signal, and receiving at least a first reflected portion of the second output optical beam and generating a second detector signal;
wherein the receiver is configured to generate an output signal in part by comparing the first detector signal and the second detector signal;
the measurement device configured to improve signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
wherein the measurement of the physiological parameter is at least in part a non-invasive measurement on blood; and
wherein the receiver is configured to lock-in to at least one of the first and second light emitting diodes.
29. The wearable device of claim 28 wherein the lock-in comprises phase locking to the at least one of the first and second light emitting diodes.
30. The wearable device of claim 28 wherein at least one of the first and second light emitting diodes is configured to operate in a pulsed mode having a pulse repetition frequency; and
wherein the lock-in comprises detection at the pulse repetition frequency to reject background signals and increase the signal-to-noise ratio of the measurement.
31. The wearable device of claim 30 , wherein the one or more detectors comprises a plurality of spatially separated detectors, the receiver further comprising one or more analog to digital converters coupled to the spatially separated detectors, the one or more analog to digital converters configured to generate at least two receiver outputs, and the measurement device configured to compare the at least two receiver outputs; and
wherein the receiver further comprises one or more spectral filters positioned in front of at least some of the spatially separated detectors.
32. The wearable device of claim 31 , wherein the receiver is further configured to:
generate a first signal from light detected while the light emitting diodes are off, and
generate a second signal from light detected while at least one of the light emitting diodes is on, wherein the detected light while at least one of the light emitting diodes is on includes at least the first reflected portion of the first or second output optical beams;
and
wherein the measurement device is configured to improve the signal-to-noise ratio of the first reflected portion of the first or second output optical beams by differencing the first signal and the second signal.
33. The wearable device of claim 28 , wherein the measurement device is configured to modulate at least one of the first light emitting diode and the second light emitting diode at a modulation frequency having a phase, and wherein the lock-in comprises filtering at the modulation frequency and locking onto the phase.
34. The wearable device of claim 33 , wherein the wearable device is configured to communicate with a smart phone or tablet, the smart phone or tablet comprising a wireless receiver, a wireless transmitter, a display, a voice input module, a speaker, and a touch screen, the smart phone or tablet configured to receive and to process at least a portion of the output signal, wherein the smart phone or tablet is configured to store and display the processed output signal, wherein at least a portion of the processed output signal is configured to be transmitted over a wireless transmission link.
35. The wearable device of claim 34 , wherein the measurement device further comprises a reflective surface positioned to redirect at least some of the first reflected portion of the first or second output optical beams toward the detectors.
36. A wearable device, comprising:
a measurement device to measure a physiological parameter adapted to be placed on a wrist or an ear of a user, comprising at least a first light emitting diode and a second light emitting diode, the first light emitting diode configured to generate a first optical beam, the first optical beam having an initial light intensity and at least one near-infrared wavelength between 700 nanometers and 2500 nanometers, the second light emitting diode configured to generate a second optical beam, the second optical beam having an initial light intensity and at least one near infrared wavelength between 700 nanometers and 2500 nanometers;
the measurement device configured to output at least a portion of the first optical beam as a first output optical beam, and to output at least a portion of the second optical beam as a second output optical beam;
the measurement device further comprising a receiver having a first detector and a second detector, the first and second detectors being spatially separated, the first detector configured to receive at least a first reflected portion of the first output optical beam and to generate a first detector signal in response, the second detector configured to receive at least a first reflected portion of the second output optical beam and to generate a second detector signal in response;
wherein at least one of the first and second detectors is located a first distance from the first light emitting diode and a different distance from the second light emitting diode and configured to receive at least a second reflected portion of the first output optical beam and to generate a third detector signal in response, and configured to receive at least a second reflected portion of the second output optical beam and to generate a fourth detector signal in response;
the measurement device configured to generate an output signal representing at least in part a non-invasive measurement on blood, the output signal generated at least in part by comparing the first detector signal with the second detector signal, and comparing the third detector signal with the fourth detector signal;
the measurement device further configured to improve the signal-to-noise ratio of the output signal by increasing light intensity relative to the initial light intensity of at least the first light emitting diode;
wherein the first and second light emitting diodes operate in a continuous wave operation mode or a pulsed operation mode; and
wherein the receiver is configured to synchronize with the operation mode of at least one of the first and second light emitting diodes.
37. The wearable device of claim 36 , wherein at least one of the first light emitting diode and the second light emitting diode is modulated at a modulation frequency, wherein the receiver is configured to detect at the modulation frequency; and
wherein the receiver is configured to perform filtering at the modulation frequency, and wherein the modulation frequency has a phase, and wherein the receiver is configured to lock onto the phase.
38. The wearable device of claim 37 , wherein the receiver is further configured to:
generate a first receiver signal responsive to light received while the first and second light emitting diodes are off, and
generate a second receiver signal responsive to light received while at least one of the first and second light emitting diodes is on, wherein the light received while at least one of the first and second light emitting diodes is on includes at least a portion of the first reflected portion of the first output optical beam or the second output optical beam;
and
wherein the measurement device is configured to further improve the signal-to-noise ratio of output signal by differencing the first receiver signal and the second receiver signal.
39. The wearable device of claim 38 , wherein the wearable device is configured to communicate with a smart phone or tablet, the smart phone or tablet comprising a wireless receiver, a wireless transmitter, a display, a voice input module, a speaker, and a touch screen, the smart phone or tablet configured to receive and to process at least a portion of the output signal, wherein the smart phone or tablet is configured to store the processed portion of the output signal, wherein at least a portion of the processed output signal is configured to be transmitted over a wireless transmission link as a transmitted signal to a remote device;
the remote device configured to receive over the wireless transmission link at least part of the transmitted signal, to process the at least part of the transmitted signal to generate processed data and to store the processed data, and wherein the remote device is capable of retrieving a history of at least a portion of the stored processed data.
40. The wearable device of claim 39 , wherein the measurement device further comprises a reflective surface positioned to receive and redirect toward the spatially separated detectors at least some of the first portion of the first optical output beam, and wherein the at least one near-infrared wavelength of the first optical beam comprises a wavelength between 900 nanometers and 1150 nanometers; and
wherein the receiver further comprises one or more spectral filters positioned in front of at least some of the spatially separated detectors.
Priority Applications (19)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16/272,069 US20190167114A1 (en) | 2012-12-31 | 2019-02-11 | Near-infrared laser diodes used in imaging applications |
US16/506,885 US10517484B2 (en) | 2012-12-31 | 2019-07-09 | Semiconductor diodes-based physiological measurement device with improved signal-to-noise ratio |
US16/540,764 US10677774B2 (en) | 2012-12-31 | 2019-08-14 | Near-infrared time-of-flight cameras and imaging |
US16/597,383 US10660526B2 (en) | 2012-12-31 | 2019-10-09 | Near-infrared time-of-flight imaging using laser diodes with Bragg reflectors |
US16/669,794 US10874304B2 (en) | 2012-12-31 | 2019-10-31 | Semiconductor source based near infrared measurement device with improved signal-to-noise ratio |
US16/722,188 US10820807B2 (en) | 2012-12-31 | 2019-12-20 | Time-of-flight measurement of skin or blood using array of laser diodes with Bragg reflectors |
US16/880,095 US10918287B2 (en) | 2012-12-31 | 2020-05-21 | System for non-invasive measurement using cameras and time of flight detection |
US16/895,727 US10928374B2 (en) | 2012-12-31 | 2020-06-08 | Non-invasive measurement of blood within the skin using array of laser diodes with Bragg reflectors and a camera system |
US17/078,771 US11160455B2 (en) | 2012-12-31 | 2020-10-23 | Multi-wavelength wearable device for non-invasive blood measurements in tissue |
US17/135,233 US11241156B2 (en) | 2012-12-31 | 2020-12-28 | Time-of-flight imaging and physiological measurements |
US17/181,887 US11353440B2 (en) | 2012-12-31 | 2021-02-22 | Time-of-flight physiological measurements and cloud services |
US17/514,778 US11564577B2 (en) | 2012-12-31 | 2021-10-29 | Wearable device coupled to time-of-flight imaging system |
US17/666,518 US11596311B2 (en) | 2012-12-31 | 2022-02-07 | Remote sensing and measurement system using time-of-flight detectors |
US17/832,340 US11678805B2 (en) | 2012-12-31 | 2022-06-03 | Active remote sensing system using time-of-flight sensor combined with cameras and wearable devices |
US18/103,408 US11896346B2 (en) | 2012-12-31 | 2023-01-30 | Short-wave infrared sensor for identifying based on water content |
US18/118,013 US20230277065A1 (en) | 2012-12-31 | 2023-03-06 | Active illumination and time-of-flight camera system to evaluate facial blood flow, eye movements and physiological parameters |
US18/211,354 US11992291B2 (en) | 2012-12-31 | 2023-06-19 | Identifying objects using near-infrared sensors, cameras or time-of-flight detectors |
US18/386,877 US20240130621A1 (en) | 2012-12-31 | 2023-11-02 | Camera based system with processing using artificial intelligence for detecting anomalous occurrences and improving performance |
US18/438,144 US20240180428A1 (en) | 2012-12-31 | 2024-02-09 | Wearable devices comprising semiconductor diode light sources with improved signal-to-noise ratio |
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261747472P | 2012-12-31 | 2012-12-31 | |
PCT/US2013/075700 WO2014105520A1 (en) | 2012-12-31 | 2013-12-17 | Near-infrared lasers for non-invasive monitoring of glucose, ketones, hba1c, and other blood constituents |
US201514650897A | 2015-06-10 | 2015-06-10 | |
US15/212,549 US9885698B2 (en) | 2012-12-31 | 2016-07-18 | Near-infrared lasers for non-invasive monitoring of glucose, ketones, HbA1C, and other blood constituents |
US15/888,052 US10136819B2 (en) | 2012-12-31 | 2018-02-04 | Short-wave infrared super-continuum lasers and similar light sources for imaging applications |
US16/029,611 US10201283B2 (en) | 2012-12-31 | 2018-07-08 | Near-infrared laser diodes used in imaging applications |
US16/272,069 US20190167114A1 (en) | 2012-12-31 | 2019-02-11 | Near-infrared laser diodes used in imaging applications |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/029,611 Continuation US10201283B2 (en) | 2012-12-31 | 2018-07-08 | Near-infrared laser diodes used in imaging applications |
US16/241,628 Continuation US10441176B2 (en) | 2012-12-31 | 2019-01-07 | Imaging using near-infrared laser diodes with distributed bragg reflectors |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/284,514 Continuation US20190183346A1 (en) | 2012-12-31 | 2019-02-25 | Near infrared imaging using laser arrays with distributed bragg reflectors |
US16/506,885 Continuation US10517484B2 (en) | 2012-12-31 | 2019-07-09 | Semiconductor diodes-based physiological measurement device with improved signal-to-noise ratio |
Publications (1)
Publication Number | Publication Date |
---|---|
US20190167114A1 true US20190167114A1 (en) | 2019-06-06 |
Family
ID=51021943
Family Applications (6)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/888,052 Expired - Fee Related US10136819B2 (en) | 2012-12-31 | 2018-02-04 | Short-wave infrared super-continuum lasers and similar light sources for imaging applications |
US16/029,611 Active - Reinstated US10201283B2 (en) | 2012-12-31 | 2018-07-08 | Near-infrared laser diodes used in imaging applications |
US16/272,069 Abandoned US20190167114A1 (en) | 2012-12-31 | 2019-02-11 | Near-infrared laser diodes used in imaging applications |
US16/506,885 Active US10517484B2 (en) | 2012-12-31 | 2019-07-09 | Semiconductor diodes-based physiological measurement device with improved signal-to-noise ratio |
US16/722,188 Active US10820807B2 (en) | 2012-12-31 | 2019-12-20 | Time-of-flight measurement of skin or blood using array of laser diodes with Bragg reflectors |
US17/078,771 Active US11160455B2 (en) | 2012-12-31 | 2020-10-23 | Multi-wavelength wearable device for non-invasive blood measurements in tissue |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/888,052 Expired - Fee Related US10136819B2 (en) | 2012-12-31 | 2018-02-04 | Short-wave infrared super-continuum lasers and similar light sources for imaging applications |
US16/029,611 Active - Reinstated US10201283B2 (en) | 2012-12-31 | 2018-07-08 | Near-infrared laser diodes used in imaging applications |
Family Applications After (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/506,885 Active US10517484B2 (en) | 2012-12-31 | 2019-07-09 | Semiconductor diodes-based physiological measurement device with improved signal-to-noise ratio |
US16/722,188 Active US10820807B2 (en) | 2012-12-31 | 2019-12-20 | Time-of-flight measurement of skin or blood using array of laser diodes with Bragg reflectors |
US17/078,771 Active US11160455B2 (en) | 2012-12-31 | 2020-10-23 | Multi-wavelength wearable device for non-invasive blood measurements in tissue |
Country Status (4)
Country | Link |
---|---|
US (6) | US10136819B2 (en) |
EP (2) | EP2938259A4 (en) |
CA (1) | CA2895969A1 (en) |
WO (1) | WO2014105520A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020257861A1 (en) * | 2019-06-27 | 2020-12-30 | Macquarie University | Diagnosis and monitoring of neurodegenerative diseases |
Families Citing this family (41)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8753121B2 (en) | 2006-04-20 | 2014-06-17 | Sonendo, Inc. | Apparatus and methods for treating root canals of teeth |
US7980854B2 (en) | 2006-08-24 | 2011-07-19 | Medical Dental Advanced Technologies Group, L.L.C. | Dental and medical treatments and procedures |
US10660526B2 (en) | 2012-12-31 | 2020-05-26 | Omni Medsci, Inc. | Near-infrared time-of-flight imaging using laser diodes with Bragg reflectors |
WO2014143276A2 (en) | 2012-12-31 | 2014-09-18 | Omni Medsci, Inc. | Short-wave infrared super-continuum lasers for natural gas leak detection, exploration, and other active remote sensing applications |
US9993159B2 (en) | 2012-12-31 | 2018-06-12 | Omni Medsci, Inc. | Near-infrared super-continuum lasers for early detection of breast and other cancers |
WO2014105520A1 (en) | 2012-12-31 | 2014-07-03 | Omni Medsci, Inc. | Near-infrared lasers for non-invasive monitoring of glucose, ketones, hba1c, and other blood constituents |
CA2911415A1 (en) | 2013-06-26 | 2014-12-31 | Sonendo, Inc. | Apparatus and methods for filling teeth and root canals |
CA2931973A1 (en) | 2013-11-29 | 2015-06-04 | Motiv Inc. | Wearable computing device |
US20160051147A1 (en) * | 2014-08-21 | 2016-02-25 | Irmed | System and method for noninvasive analysis of subcutaneous tissue |
US10709365B2 (en) | 2014-08-21 | 2020-07-14 | I. R. Med Ltd. | System and method for noninvasive analysis of subcutaneous tissue |
US10772541B2 (en) | 2014-08-21 | 2020-09-15 | I. R. Med Ltd. | System and method for noninvasive analysis of subcutaneous tissue |
US20180227735A1 (en) | 2014-08-25 | 2018-08-09 | Phyziio, Inc. | Proximity-Based Attribution of Rewards |
WO2016054079A1 (en) | 2014-09-29 | 2016-04-07 | Zyomed Corp. | Systems and methods for blood glucose and other analyte detection and measurement using collision computing |
CA3010164C (en) | 2015-12-31 | 2024-03-12 | Wear2B Ltd | Device, system and method for non-invasive monitoring of physiological measurements |
US9554738B1 (en) | 2016-03-30 | 2017-01-31 | Zyomed Corp. | Spectroscopic tomography systems and methods for noninvasive detection and measurement of analytes using collision computing |
CN115177241A (en) * | 2016-05-02 | 2022-10-14 | 德克斯康公司 | System and method for providing alerts optimized for a user |
US20190234869A1 (en) * | 2016-09-13 | 2019-08-01 | The General Hospital Corporation | Systems and methods for characterizing biological material using near-infrared spectroscopy |
CN107889130B (en) | 2016-09-29 | 2023-04-18 | 华为技术有限公司 | Wireless resource selection method and device |
US20210275084A1 (en) * | 2017-04-18 | 2021-09-09 | Flare Diagnostics, Llc | Skin Test Reading Device and Associate Systems and Methods |
CN107894406B (en) * | 2017-10-23 | 2019-08-20 | 深圳市太赫兹系统设备有限公司 | Control method, device, storage medium and the computer equipment of ftir analysis instrument |
CA3089642A1 (en) | 2018-02-09 | 2019-08-15 | Dexcom, Inc. | System and method for decision support |
JP6871197B2 (en) * | 2018-05-01 | 2021-05-12 | 日本電信電話株式会社 | Component concentration measuring device |
US11918352B2 (en) | 2018-05-15 | 2024-03-05 | Isbrg Corp. | Non-invasive determination of a physiological state of interest in a subject |
US11864906B2 (en) * | 2019-06-20 | 2024-01-09 | International Business Machines Corporation | LIDAR implantable biosensor for imaging biological tissue |
US11950881B2 (en) | 2019-07-28 | 2024-04-09 | Holovsions LLC | Smart bra for optical scanning of breast tissue to detect abnormal tissue with selectively-expandable components to reduce air gaps |
US11304456B2 (en) | 2019-07-28 | 2022-04-19 | Holovisions LLC | Smart bra with optical sensors to detect abnormal breast tissue |
US11581696B2 (en) | 2019-08-14 | 2023-02-14 | Open Water Internet Inc. | Multi-channel laser |
TWI714221B (en) * | 2019-08-19 | 2020-12-21 | 國立中央大學 | Transmissive light based tremor identification method and system thereof |
US11940565B2 (en) | 2019-08-20 | 2024-03-26 | Luminar Technologies, Inc. | Coherent pulsed lidar system |
GB2590498A (en) * | 2019-12-20 | 2021-06-30 | Reid Steven | Blood glucose monitor |
DE102020202823A1 (en) | 2020-03-05 | 2021-09-09 | OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung | OPTOELECTRONIC DEVICE AND METHOD FOR DETERMINING THE DISTRIBUTION OF A SUBSTANCE IN A SAMPLE |
KR20210142304A (en) * | 2020-05-18 | 2021-11-25 | 삼성전자주식회사 | Apparatus and method for calibration of optical sensor, the optical sensor and apparatus for estimating bio-information |
US20220043202A1 (en) * | 2020-08-10 | 2022-02-10 | Luminar, Llc | Semiconductor optical amplifier with bragg grating |
USD997355S1 (en) | 2020-10-07 | 2023-08-29 | Sonendo, Inc. | Dental treatment instrument |
CA3207932A1 (en) * | 2021-02-12 | 2022-08-18 | Jordan MACINTYRE | Non-invasive determination of a physiological state of interest in a subject from spectral data processed using a trained machine learning model |
CN113171091B (en) * | 2021-04-22 | 2023-03-21 | 北京航空航天大学 | Implantable hydrogel fiber bragg grating glucose sensor, preparation method and measurement system |
CN113447205B (en) * | 2021-06-28 | 2024-06-11 | 广东正扬传感科技股份有限公司 | Near-infrared camera gas leakage detection system and detection method thereof |
GB2605856B (en) * | 2021-11-23 | 2024-04-03 | Haxha Shyqyri | Apparatus and method of capturing physiological data |
EP4201305A1 (en) * | 2021-12-22 | 2023-06-28 | University College Cork, National University Of Ireland | A fetal monitoring device |
US20240099617A1 (en) * | 2022-09-28 | 2024-03-28 | Applied Materials, Inc. | Diffuse optical imaging/tomography using meta-optics |
CN115561741B (en) * | 2022-12-07 | 2023-04-11 | 中国电子科技集团公司第十研究所 | Distance measurement method suitable for cloud measurement and control architecture |
Family Cites Families (285)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1569450A (en) | 1976-05-27 | 1980-06-18 | Nippon Electric Co | Speech recognition system |
US4063106A (en) | 1977-04-25 | 1977-12-13 | Bell Telephone Laboratories, Incorporated | Optical fiber Raman oscillator |
US4221997A (en) | 1978-12-18 | 1980-09-09 | Western Electric Company, Incorporated | Articulated robot arm and method of moving same |
US4275266A (en) | 1979-03-26 | 1981-06-23 | Theodore Lasar | Device to control machines by voice |
JPS56151019A (en) | 1980-04-25 | 1981-11-21 | Olympus Optical Co | Release apparatus of endoscope photographing system |
US4605080A (en) | 1980-07-11 | 1986-08-12 | Lemelson Jerome H | Speech recognition control system and method |
FR2492304A1 (en) | 1980-10-17 | 1982-04-23 | Commissariat Energie Atomique | TELEMANIPULATION ASSEMBLY MOUNTED ON A MOBILE PLATFORM AND COMPRISING A RETRACTABLE TELESCOPIC CARRIER ASSEMBLY WITHIN A SEALED HOOD, AND METHOD FOR SETTING UP ON AN ENCLOSURE |
JPS57147912A (en) | 1981-03-09 | 1982-09-13 | Toyota Motor Corp | Control device by voice for air conditioner |
US4374618A (en) | 1981-03-16 | 1983-02-22 | Ibm Corporation | Microfilm camera having a moving lens |
US4462080A (en) | 1981-11-27 | 1984-07-24 | Kearney & Trecker Corporation | Voice actuated machine control |
US4641292A (en) | 1983-06-20 | 1987-02-03 | George Tunnell | Voice controlled welding system |
US4704696A (en) | 1984-01-26 | 1987-11-03 | Texas Instruments Incorporated | Method and apparatus for voice control of a computer |
JPS61279491A (en) | 1985-05-31 | 1986-12-10 | 株式会社安川電機 | Visual apparatus holder |
US4776016A (en) | 1985-11-21 | 1988-10-04 | Position Orientation Systems, Inc. | Voice control system |
US5078140A (en) | 1986-05-08 | 1992-01-07 | Kwoh Yik S | Imaging device - aided robotic stereotaxis system |
GB8708148D0 (en) | 1987-04-06 | 1987-05-13 | British Telecomm | Radiation pulse generation |
US4762455A (en) | 1987-06-01 | 1988-08-09 | Remote Technology Corporation | Remote manipulator |
US5303148A (en) | 1987-11-27 | 1994-04-12 | Picker International, Inc. | Voice actuated volume image controller and display controller |
US4989253A (en) | 1988-04-15 | 1991-01-29 | The Montefiore Hospital Association Of Western Pennsylvania | Voice activated microscope |
US4972331A (en) | 1989-02-06 | 1990-11-20 | Nim, Inc. | Phase modulated spectrophotometry |
US6708048B1 (en) | 1989-02-06 | 2004-03-16 | Non-Invasive Technology, Inc. | Phase modulation spectrophotometric apparatus |
US5180378A (en) | 1989-04-24 | 1993-01-19 | Abiomed, Inc. | Laser surgery system |
CA2028261C (en) * | 1989-10-28 | 1995-01-17 | Won Suck Yang | Non-invasive method and apparatus for measuring blood glucose concentration |
EP0427358B1 (en) | 1989-11-08 | 1996-03-27 | George S. Allen | Mechanical arm for and interactive image-guided surgical system |
US5267323A (en) | 1989-12-29 | 1993-11-30 | Pioneer Electronic Corporation | Voice-operated remote control system |
JP2964518B2 (en) | 1990-01-30 | 1999-10-18 | 日本電気株式会社 | Voice control method |
US5246004A (en) | 1990-02-02 | 1993-09-21 | Angiomedics Ii, Inc. | Infrared cholesterol sensor |
US5086401A (en) | 1990-05-11 | 1992-02-04 | International Business Machines Corporation | Image-directed robotic system for precise robotic surgery including redundant consistency checking |
US5084880A (en) | 1990-07-02 | 1992-01-28 | The United States Of America As Represented By The Sectretary Of The Navy | Erbium-doped fluorozirconate fiber laser pumped by a diode laser source |
GB2249682B (en) | 1990-11-09 | 1995-03-29 | Stc Plc | Optical amplifiers |
US5134620A (en) | 1990-11-20 | 1992-07-28 | General Instrument Corporation | Laser with longitudinal mode selection |
US5300097A (en) | 1991-02-13 | 1994-04-05 | Lerner Ethan A | Fiber optic psoriasis treatment device |
US5313306A (en) | 1991-05-13 | 1994-05-17 | Telerobotics International, Inc. | Omniview motionless camera endoscopy system |
JP3173042B2 (en) | 1991-05-21 | 2001-06-04 | ソニー株式会社 | Robot numerical controller |
US5279309A (en) | 1991-06-13 | 1994-01-18 | International Business Machines Corporation | Signaling device and method for monitoring positions in a surgical operation |
US5417210A (en) | 1992-05-27 | 1995-05-23 | International Business Machines Corporation | System and method for augmentation of endoscopic surgery |
US5348552A (en) | 1991-08-30 | 1994-09-20 | Hoya Corporation | Laser surgical unit |
JP2579394B2 (en) | 1991-09-13 | 1997-02-05 | 日本電信電話株式会社 | WDM mode-locked laser device |
US5345538A (en) | 1992-01-27 | 1994-09-06 | Krishna Narayannan | Voice activated control apparatus |
US5218655A (en) | 1992-05-29 | 1993-06-08 | At&T Bell Laboratories | Article comprising an optical waveguide with in-line refractive index grating |
FR2695503B1 (en) | 1992-09-04 | 1994-10-21 | Thomson Csf | Wireless medical data transmission system. |
US5368224A (en) | 1992-10-23 | 1994-11-29 | Nellcor Incorporated | Method for reducing ambient noise effects in electronic monitoring instruments |
DE4329898A1 (en) | 1993-09-04 | 1995-04-06 | Marcus Dr Besson | Wireless medical diagnostic and monitoring device |
US5400165A (en) | 1993-09-10 | 1995-03-21 | At&T Corp. | Optical communication using dispersion-induced FM to AM conversion with nonlinearity-induced stabilization |
US5323404A (en) | 1993-11-02 | 1994-06-21 | At&T Bell Laboratories | Optical fiber laser or amplifier including high reflectivity gratings |
US5381798A (en) | 1993-11-02 | 1995-01-17 | Quinton Instrument Company | Spread spectrum telemetry of physiological signals |
US5497769A (en) | 1993-12-16 | 1996-03-12 | I.S.S. (Usa) Inc. | Photosensor with multiple light sources |
US5645059A (en) | 1993-12-17 | 1997-07-08 | Nellcor Incorporated | Medical sensor with modulated encoding scheme |
US5795300A (en) | 1994-06-01 | 1998-08-18 | Advanced Body Metrics Corporation | Heart pulse monitor |
US6463361B1 (en) | 1994-09-22 | 2002-10-08 | Computer Motion, Inc. | Speech interface for an automated endoscopic system |
US6646541B1 (en) | 1996-06-24 | 2003-11-11 | Computer Motion, Inc. | General purpose distributed operating room control system |
US5687734A (en) | 1994-10-20 | 1997-11-18 | Hewlett-Packard Company | Flexible patient monitoring system featuring a multiport transmitter |
US5563710A (en) | 1994-10-28 | 1996-10-08 | The Schepens Eye Research Institute, Inc. | Imaging system with confocally self-detecting laser |
US5704351A (en) | 1995-02-28 | 1998-01-06 | Mortara Instrument, Inc. | Multiple channel biomedical digital telemetry transmitter |
US5524617A (en) | 1995-03-14 | 1996-06-11 | Nellcor, Incorporated | Isolated layer pulse oximetry |
US5774213A (en) | 1995-04-21 | 1998-06-30 | Trebino; Rick P. | Techniques for measuring difference of an optical property at two wavelengths by modulating two sources to have opposite-phase components at a common frequency |
US5696778A (en) | 1995-05-09 | 1997-12-09 | Ophir Corporation | Method of and apparatus for generating intracavity double raman shifted laser pulses |
US5544654A (en) | 1995-06-06 | 1996-08-13 | Acuson Corporation | Voice control of a medical ultrasound scanning machine |
US6931268B1 (en) | 1995-06-07 | 2005-08-16 | Masimo Laboratories, Inc. | Active pulse blood constituent monitoring |
IL122515A (en) | 1995-06-09 | 1999-10-28 | Cybro Medical Ltd | Sensor method and device for optical blood oximetry |
US5631758A (en) | 1995-10-26 | 1997-05-20 | Lucent Technologies Inc. | Chirped-pulse multiple wavelength telecommunications system |
US5970457A (en) | 1995-10-25 | 1999-10-19 | Johns Hopkins University | Voice command and control medical care system |
US5748103A (en) | 1995-11-13 | 1998-05-05 | Vitalcom, Inc. | Two-way TDMA telemetry system with power conservation features |
US5944659A (en) | 1995-11-13 | 1999-08-31 | Vitalcom Inc. | Architecture for TDMA medical telemetry system |
US5867305A (en) | 1996-01-19 | 1999-02-02 | Sdl, Inc. | Optical amplifier with high energy levels systems providing high peak powers |
US5747806A (en) | 1996-02-02 | 1998-05-05 | Instrumentation Metrics, Inc | Method and apparatus for multi-spectral analysis in noninvasive nir spectroscopy |
US6436107B1 (en) | 1996-02-20 | 2002-08-20 | Computer Motion, Inc. | Method and apparatus for performing minimally invasive surgical procedures |
US6735471B2 (en) | 1996-04-30 | 2004-05-11 | Medtronic, Inc. | Method and system for endotracheal/esophageal stimulation prior to and during a medical procedure |
US5792204A (en) | 1996-05-08 | 1998-08-11 | Pacesetter, Inc. | Methods and apparatus for controlling an implantable device programmer using voice commands |
US5912910A (en) | 1996-05-17 | 1999-06-15 | Sdl, Inc. | High power pumped mid-IR wavelength systems using nonlinear frequency mixing (NFM) devices |
US6325978B1 (en) | 1998-08-04 | 2001-12-04 | Ntc Technology Inc. | Oxygen monitoring and apparatus |
US5718234A (en) | 1996-09-30 | 1998-02-17 | Northrop Grumman Corporation | Physiological data communication system |
US6847336B1 (en) | 1996-10-02 | 2005-01-25 | Jerome H. Lemelson | Selectively controllable heads-up display system |
US6212310B1 (en) | 1996-10-22 | 2001-04-03 | Sdl, Inc. | High power fiber gain media system achieved through power scaling via multiplexing |
US6364834B1 (en) | 1996-11-13 | 2002-04-02 | Criticare Systems, Inc. | Method and system for remotely monitoring multiple medical parameters in an integrated medical monitoring system |
US5855550A (en) | 1996-11-13 | 1999-01-05 | Lai; Joseph | Method and system for remotely monitoring multiple medical parameters |
US5812978A (en) | 1996-12-09 | 1998-09-22 | Tracer Round Associaties, Ltd. | Wheelchair voice control apparatus |
US5880877A (en) | 1997-01-28 | 1999-03-09 | Imra America, Inc. | Apparatus and method for the generation of high-power femtosecond pulses from a fiber amplifier |
US5998759A (en) | 1996-12-24 | 1999-12-07 | General Scanning, Inc. | Laser processing |
US5810801A (en) | 1997-02-05 | 1998-09-22 | Candela Corporation | Method and apparatus for treating wrinkles in skin using radiation |
US5912749A (en) | 1997-02-11 | 1999-06-15 | Lucent Technologies Inc. | Call admission control in cellular networks |
US6200309B1 (en) | 1997-02-13 | 2001-03-13 | Mcdonnell Douglas Corporation | Photodynamic therapy system and method using a phased array raman laser amplifier |
US5919134A (en) | 1997-04-14 | 1999-07-06 | Masimo Corp. | Method and apparatus for demodulating signals in a pulse oximetry system |
JPH10303822A (en) | 1997-04-25 | 1998-11-13 | Furukawa Electric Co Ltd:The | Optical transmitting device |
US7890158B2 (en) | 2001-06-05 | 2011-02-15 | Lumidigm, Inc. | Apparatus and method of biometric determination using specialized optical spectroscopy systems |
US6043927A (en) | 1997-06-26 | 2000-03-28 | University Of Michigan | Modulation instability wavelength converter |
US7010336B2 (en) | 1997-08-14 | 2006-03-07 | Sensys Medical, Inc. | Measurement site dependent data preprocessing method for robust calibration and prediction |
US6115673A (en) | 1997-08-14 | 2000-09-05 | Instrumentation Metrics, Inc. | Method and apparatus for generating basis sets for use in spectroscopic analysis |
US7206623B2 (en) | 2000-05-02 | 2007-04-17 | Sensys Medical, Inc. | Optical sampling interface system for in vivo measurement of tissue |
US6181414B1 (en) | 1998-02-06 | 2001-01-30 | Morphometrix Technologies Inc | Infrared spectroscopy for medical imaging |
US6083167A (en) | 1998-02-10 | 2000-07-04 | Emory University | Systems and methods for providing radiation therapy and catheter guides |
US6525386B1 (en) | 1998-03-10 | 2003-02-25 | Masimo Corporation | Non-protruding optoelectronic lens |
US6374006B1 (en) | 1998-03-20 | 2002-04-16 | Xtera Communications, Inc. | Chirped period gratings for raman amplification in circulator loop cavities |
US6760148B2 (en) | 1998-03-24 | 2004-07-06 | Xtera Communications, Inc. | Nonlinear polarization amplifiers in nonzero dispersion shifted fiber |
US6078833A (en) | 1998-03-25 | 2000-06-20 | I.S.S. (Usa) Inc. | Self referencing photosensor |
WO1999049937A1 (en) | 1998-03-27 | 1999-10-07 | The General Hospital Corporation | Method and apparatus for the selective targeting of lipid-rich tissues |
US6213998B1 (en) | 1998-04-02 | 2001-04-10 | Vanderbilt University | Laser surgical cutting probe and system |
US6450172B1 (en) | 1998-04-29 | 2002-09-17 | Medtronic, Inc. | Broadcast audible sound communication from an implantable medical device |
US6885498B2 (en) | 1998-06-16 | 2005-04-26 | Xtera Communications, Inc. | Multi-stage optical amplifier and broadband communication system |
US6126655A (en) | 1998-08-11 | 2000-10-03 | The General Hospital Corporation | Apparatus and method for selective laser-induced heating of biological tissue |
US6087182A (en) | 1998-08-27 | 2000-07-11 | Abbott Laboratories | Reagentless analysis of biological samples |
US6185535B1 (en) | 1998-10-16 | 2001-02-06 | Telefonaktiebolaget Lm Ericsson (Publ) | Voice control of a user interface to service applications |
US6246707B1 (en) | 1998-11-18 | 2001-06-12 | Photonics Industries International, Inc. | High repetition rate pulsed laser |
US6659939B2 (en) | 1998-11-20 | 2003-12-09 | Intuitive Surgical, Inc. | Cooperative minimally invasive telesurgical system |
US6246896B1 (en) | 1998-11-24 | 2001-06-12 | General Electric Company | MRI guided ablation system |
US6224542B1 (en) | 1999-01-04 | 2001-05-01 | Stryker Corporation | Endoscopic camera system with non-mechanical zoom |
US6864978B1 (en) | 1999-07-22 | 2005-03-08 | Sensys Medical, Inc. | Method of characterizing spectrometer instruments and providing calibration models to compensate for instrument variation |
US6587702B1 (en) | 1999-01-22 | 2003-07-01 | Instrumentation Metrics, Inc | Classification and characterization of tissue through features related to adipose tissue |
US6381391B1 (en) | 1999-02-19 | 2002-04-30 | The Regents Of The University Of Michigan | Method and system for generating a broadband spectral continuum and continuous wave-generating system utilizing same |
US6480656B1 (en) | 1999-02-19 | 2002-11-12 | The Regents Of The University Of Michigan | Method and system for generating a broadband spectral continuum, method of making the system and pulse-generating system utilizing same |
US6285897B1 (en) | 1999-04-07 | 2001-09-04 | Endonetics, Inc. | Remote physiological monitoring system |
US7299080B2 (en) | 1999-10-08 | 2007-11-20 | Sensys Medical, Inc. | Compact apparatus for noninvasive measurement of glucose through near-infrared spectroscopy |
US6269108B1 (en) | 1999-05-26 | 2001-07-31 | University Of Central Florida | Multi-wavelengths infrared laser |
US6512936B1 (en) | 1999-07-22 | 2003-01-28 | Sensys Medical, Inc. | Multi-tier method of classifying sample spectra for non-invasive blood analyte prediction |
US7904139B2 (en) | 1999-08-26 | 2011-03-08 | Non-Invasive Technology Inc. | Optical examination of biological tissue using non-contact irradiation and detection |
US6802811B1 (en) | 1999-09-17 | 2004-10-12 | Endoluminal Therapeutics, Inc. | Sensing, interrogating, storing, telemetering and responding medical implants |
US6454705B1 (en) | 1999-09-21 | 2002-09-24 | Cardiocom | Medical wellness parameters management system, apparatus and method |
US6402691B1 (en) | 1999-09-21 | 2002-06-11 | Herschel Q. Peddicord | In-home patient monitoring system |
US7317938B2 (en) | 1999-10-08 | 2008-01-08 | Sensys Medical, Inc. | Method of adapting in-vitro models to aid in noninvasive glucose determination |
US6453201B1 (en) | 1999-10-20 | 2002-09-17 | Cardiac Pacemakers, Inc. | Implantable medical device with voice responding and recording capacity |
US6407853B1 (en) | 1999-10-29 | 2002-06-18 | Corning Incorporated | Broadhead dual wavelength pumped fiber amplifier |
US6340806B1 (en) | 1999-12-28 | 2002-01-22 | General Scanning Inc. | Energy-efficient method and system for processing target material using an amplified, wavelength-shifted pulse train |
US6281471B1 (en) | 1999-12-28 | 2001-08-28 | Gsi Lumonics, Inc. | Energy-efficient, laser-based method and system for processing target material |
WO2001052372A1 (en) | 2000-01-12 | 2001-07-19 | Xtera Communications, Inc. | Raman amplifier with bi-directional pumping |
CA2397297A1 (en) | 2000-01-14 | 2001-07-19 | Ao-Entwicklungsinstitut Davos | Device for moving a medical apparatus in a controlled manner |
RU2158458C1 (en) | 2000-02-08 | 2000-10-27 | Научный центр волоконной оптики при Институте общей физики РАН | Raman fiber laser |
US6893396B2 (en) | 2000-03-01 | 2005-05-17 | I-Medik, Inc. | Wireless internet bio-telemetry monitoring system and interface |
US6443890B1 (en) | 2000-03-01 | 2002-09-03 | I-Medik, Inc. | Wireless internet bio-telemetry monitoring system |
US6441747B1 (en) | 2000-04-18 | 2002-08-27 | Motorola, Inc. | Wireless system protocol for telemetry monitoring |
US6611368B1 (en) | 2000-04-20 | 2003-08-26 | Lucent Technologies Inc. | Time-division multiplexed pump wavelengths resulting in ultra broad band, flat, backward pumped Raman gain |
FR2808186B1 (en) | 2000-04-27 | 2003-02-21 | Alm | OPERATING TABLE CONTROL SYSTEM AND OPERATING TABLE COMPRISING SUCH A SYSTEM |
US6534012B1 (en) | 2000-08-02 | 2003-03-18 | Sensys Medical, Inc. | Apparatus and method for reproducibly modifying localized absorption and scattering coefficients at a tissue measurement site during optical sampling |
US7519406B2 (en) | 2004-04-28 | 2009-04-14 | Sensys Medical, Inc. | Noninvasive analyzer sample probe interface method and apparatus |
JP4042340B2 (en) | 2000-05-17 | 2008-02-06 | カシオ計算機株式会社 | Information equipment |
ES2362414T3 (en) | 2000-05-19 | 2011-07-05 | Welch Allyn Protocol Inc | PATIENT MONITORING SYSTEM. |
US6885683B1 (en) | 2000-05-23 | 2005-04-26 | Imra America, Inc. | Modular, high energy, widely-tunable ultrafast fiber source |
US7394591B2 (en) | 2000-05-23 | 2008-07-01 | Imra America, Inc. | Utilization of Yb: and Nd: mode-locked oscillators in solid-state short pulse laser systems |
US7395158B2 (en) | 2000-05-30 | 2008-07-01 | Sensys Medical, Inc. | Method of screening for disorders of glucose metabolism |
WO2001095800A2 (en) | 2000-06-15 | 2001-12-20 | Instrumentation Metrics, Inc. | Classification and screening of test subjects according to optical thickness of skin |
DE20122782U1 (en) | 2000-06-17 | 2007-11-15 | Leica Microsystems Cms Gmbh | lighting device |
EP1293018B1 (en) | 2000-06-20 | 2004-10-13 | Evotec OAI AG | Fiber laser |
US6509566B1 (en) | 2000-06-22 | 2003-01-21 | Ophir Corporation | Oil and gas exploration system and method for detecting trace amounts of hydrocarbon gases in the atmosphere |
US6659947B1 (en) | 2000-07-13 | 2003-12-09 | Ge Medical Systems Information Technologies, Inc. | Wireless LAN architecture for integrated time-critical and non-time-critical services within medical facilities |
DE10047237A1 (en) | 2000-09-23 | 2002-04-11 | Physoptics Opto Electronic Gmb | System for recording the retinal reflex image |
US6816241B2 (en) | 2000-09-26 | 2004-11-09 | Sensys Medical, Inc. | LED light source-based instrument for non-invasive blood analyte determination |
US6640117B2 (en) | 2000-09-26 | 2003-10-28 | Sensys Medical, Inc. | Method and apparatus for minimizing spectral effects attributable to tissue state variations during NIR-based non-invasive blood analyte determination |
AU2001294879A1 (en) | 2000-09-29 | 2002-04-08 | Lifelink, Inc. | Wireless gateway capable of communicating according to a plurality of protocols |
AU2002211822A1 (en) | 2000-09-29 | 2002-04-08 | Lifelink, Inc. | System and method for wireless communication of sensed data to a central server |
US6505133B1 (en) | 2000-11-15 | 2003-01-07 | Datex-Ohmeda, Inc. | Simultaneous signal attenuation measurements utilizing code division multiplexing |
US6442430B1 (en) | 2000-12-04 | 2002-08-27 | Medtronic, Inc. | Implantable medical device programmers having headset video and methods of using same |
JP4071113B2 (en) | 2001-01-26 | 2008-04-02 | センシス メディカル インク | Noninvasive measurement of glucose by optical properties of tissue |
WO2002064032A2 (en) | 2001-02-14 | 2002-08-22 | Siemens Medical Solutions Usa, Inc. | Patient monitoring area network |
US20020178003A1 (en) | 2001-03-09 | 2002-11-28 | Motorola, Inc. | Method and apparatus for providing voice recognition service to a wireless communication device |
US7127401B2 (en) | 2001-03-12 | 2006-10-24 | Ge Medical Systems Global Technology Company, Llc | Remote control of a medical device using speech recognition and foot controls |
SE0101004D0 (en) | 2001-03-21 | 2001-03-21 | Astrazeneca Ab | New measuring technique |
US6898451B2 (en) | 2001-03-21 | 2005-05-24 | Minformed, L.L.C. | Non-invasive blood analyte measuring system and method utilizing optical absorption |
US8174394B2 (en) * | 2001-04-11 | 2012-05-08 | Trutouch Technologies, Inc. | System for noninvasive determination of analytes in tissue |
US6769911B2 (en) | 2001-04-16 | 2004-08-03 | Advanced Research & Technology Institue | Luminescence assisted caries excavation |
US6731967B1 (en) | 2001-07-16 | 2004-05-04 | Pacesetter, Inc. | Methods and devices for vascular plethysmography via modulation of source intensity |
JP5196459B2 (en) | 2001-07-31 | 2013-05-15 | 独立行政法人科学技術振興機構 | Broadband tunable laser beam generator |
US6943936B2 (en) | 2001-08-03 | 2005-09-13 | The Regents Of The University Of Michigan | Co-propagating Raman amplifiers |
US6788965B2 (en) | 2001-08-03 | 2004-09-07 | Sensys Medical, Inc. | Intelligent system for detecting errors and determining failure modes in noninvasive measurement of blood and tissue analytes |
US6701170B2 (en) | 2001-11-02 | 2004-03-02 | Nellcor Puritan Bennett Incorporated | Blind source separation of pulse oximetry signals |
US7005645B2 (en) | 2001-11-30 | 2006-02-28 | Air Liquide America L.P. | Apparatus and methods for launching and receiving a broad wavelength range source |
US7209657B1 (en) | 2001-12-03 | 2007-04-24 | Cheetah Omni, Llc | Optical routing using a star switching fabric |
US7046362B2 (en) | 2001-12-12 | 2006-05-16 | Trustees Of Princeton University | Fiber-optic based cavity ring-down spectroscopy apparatus |
US7318909B2 (en) | 2001-12-12 | 2008-01-15 | Trustees Of Princeton University | Method and apparatus for enhanced evanescent field exposure in an optical fiber resonator for spectroscopic detection and measurement of trace species |
TWI284200B (en) | 2002-03-08 | 2007-07-21 | Sensys Medcial Inc | Compact apparatus for noninvasive measurement of glucose through near-infrared spectroscopy |
US7697966B2 (en) | 2002-03-08 | 2010-04-13 | Sensys Medical, Inc. | Noninvasive targeting system method and apparatus |
US8328420B2 (en) | 2003-04-22 | 2012-12-11 | Marcio Marc Abreu | Apparatus and method for measuring biologic parameters |
US7294105B1 (en) | 2002-09-03 | 2007-11-13 | Cheetah Omni, Llc | System and method for a wireless medical communication system |
US7259906B1 (en) | 2002-09-03 | 2007-08-21 | Cheetah Omni, Llc | System and method for voice control of medical devices |
US7620674B2 (en) | 2003-03-07 | 2009-11-17 | Sensys Medical, Inc. | Method and apparatus for enhanced estimation of an analyte property through multiple region transformation |
CA2458123C (en) | 2003-03-13 | 2012-05-15 | Synodon Inc. | Remote sensing of gas leaks |
US7330301B2 (en) | 2003-05-14 | 2008-02-12 | Imra America, Inc. | Inexpensive variable rep-rate source for high-energy, ultrafast lasers |
US8213007B2 (en) | 2003-05-27 | 2012-07-03 | Optotrace Technologies, Inc. | Spectrally sensing chemical and biological substances |
US7847234B2 (en) | 2003-08-06 | 2010-12-07 | The United States Of America As Represented By The Secretary Of The Army | Method and system for observing a subject at a first location based upon quantum properties measured at a second location |
WO2005013843A2 (en) | 2003-08-08 | 2005-02-17 | The Regents Of The Univeristy Of California | Near-infrared transillumination for the imaging of early dental decay |
US20050049468A1 (en) | 2003-09-03 | 2005-03-03 | Sven-Erik Carlson | Increasing the performance of an optical pulsoximeter |
US20060283931A1 (en) | 2003-09-22 | 2006-12-21 | University Of Maryland, Baltimore | Product authentication |
WO2005059510A2 (en) | 2003-12-11 | 2005-06-30 | The Regents Of The University Of California | Catheter-based mid-infrared reflectance and reflectance generated absorption spectroscopy |
US6952005B2 (en) | 2003-12-19 | 2005-10-04 | Infineon Technologies Ag | Optical receiver circuit |
GB0329629D0 (en) | 2003-12-22 | 2004-01-28 | Blazephotonics Ltd | A light source |
EP1706788B1 (en) | 2004-01-23 | 2009-10-07 | Koheras A/S | Method of generating supercontinuum optical radiation, supercontinuum optical radiation source, and use thereof |
US7356364B1 (en) * | 2004-01-23 | 2008-04-08 | University Of Hawai'i | Device for optical monitoring of constituent in tissue or body fluid sample using wavelength modulation spectroscopy, such as for blood glucose levels |
US7278966B2 (en) | 2004-01-31 | 2007-10-09 | Nokia Corporation | System, method and computer program product for managing physiological information relating to a terminal user |
US20050209516A1 (en) | 2004-03-22 | 2005-09-22 | Jacob Fraden | Vital signs probe |
JP4476664B2 (en) | 2004-03-26 | 2010-06-09 | セイコーインスツル株式会社 | Biological information measuring device |
US7184148B2 (en) | 2004-05-14 | 2007-02-27 | Medeikon Corporation | Low coherence interferometry utilizing phase |
US7848605B2 (en) | 2004-05-24 | 2010-12-07 | Trutouch Technologies, Inc. | Method of making optical probes for non-invasive analyte measurements |
US9341565B2 (en) | 2004-07-07 | 2016-05-17 | Masimo Corporation | Multiple-wavelength physiological monitor |
US9820658B2 (en) | 2006-06-30 | 2017-11-21 | Bao Q. Tran | Systems and methods for providing interoperability among healthcare devices |
US8172761B1 (en) | 2004-09-28 | 2012-05-08 | Impact Sports Technologies, Inc. | Monitoring device with an accelerometer, method and system |
US7468036B1 (en) | 2004-09-28 | 2008-12-23 | Impact Sports Technology, Inc. | Monitoring device, method and system |
CN101080192B (en) | 2004-12-14 | 2010-09-08 | 皇家飞利浦电子股份有限公司 | Integrated pulse oximetry sensor |
WO2006078963A2 (en) | 2005-01-21 | 2006-07-27 | Omni Sciences, Inc. | Method and system for generating mid-infrared light |
US20060268393A1 (en) | 2005-01-21 | 2006-11-30 | Omni Sciences, Inc. | System and method for generating supercontinuum light |
US7420994B2 (en) | 2005-03-04 | 2008-09-02 | Corning Incorporated | Pulsed cascaded Raman laser |
JP5001934B2 (en) * | 2005-04-15 | 2012-08-15 | バイエル・ヘルスケア・エルエルシー | Non-invasive system and method for measuring body glucose |
US20060281982A1 (en) * | 2005-06-14 | 2006-12-14 | Diasense, Inc. | Method and apparatus for the non-invasive sensing of glucose in a human subject |
EP1902341A2 (en) | 2005-07-08 | 2008-03-26 | Koheras A/S | Blue extended super continuum light source |
WO2007009234A1 (en) * | 2005-07-18 | 2007-01-25 | Andreas Mandelis | Method and apparatus using infrared photothermal radiometry (ptr) and modulated laser luminescence (lum) for diagnostics of defects in teeth |
US7377865B2 (en) | 2005-11-18 | 2008-05-27 | Stx, Llc | Bowed field hockey stick |
US7519253B2 (en) | 2005-11-18 | 2009-04-14 | Omni Sciences, Inc. | Broadband or mid-infrared fiber light sources |
JP5095986B2 (en) | 2005-11-30 | 2012-12-12 | 学校法人慶應義塾 | Non-nail invasive blood substance measuring device and nail plate transpiration device |
US7648463B1 (en) | 2005-12-15 | 2010-01-19 | Impact Sports Technologies, Inc. | Monitoring device, method and system |
US7558622B2 (en) | 2006-05-24 | 2009-07-07 | Bao Tran | Mesh network stroke monitoring appliance |
US7807718B2 (en) | 2006-06-30 | 2010-10-05 | Sami A. Hashim | Glyceride esters for the treatment of diseases associated with reduced neuronal metabolism of glucose |
US7969558B2 (en) | 2006-07-13 | 2011-06-28 | Velodyne Acoustics Inc. | High definition lidar system |
US7771320B2 (en) | 2006-09-07 | 2010-08-10 | Nike, Inc. | Athletic performance sensing and/or tracking systems and methods |
US8447087B2 (en) | 2006-09-12 | 2013-05-21 | Carestream Health, Inc. | Apparatus and method for caries detection |
US20080076972A1 (en) | 2006-09-21 | 2008-03-27 | Apple Inc. | Integrated sensors for tracking performance metrics |
US8956290B2 (en) | 2006-09-21 | 2015-02-17 | Apple Inc. | Lifestyle companion system |
US9192329B2 (en) | 2006-10-12 | 2015-11-24 | Masimo Corporation | Variable mode pulse indicator |
JP5036276B2 (en) | 2006-11-02 | 2012-09-26 | 株式会社ディスコ | Laser processing equipment |
US8157730B2 (en) | 2006-12-19 | 2012-04-17 | Valencell, Inc. | Physiological and environmental monitoring systems and methods |
WO2008120217A2 (en) | 2007-04-02 | 2008-10-09 | Prime Sense Ltd. | Depth mapping using projected patterns |
US8150142B2 (en) | 2007-04-02 | 2012-04-03 | Prime Sense Ltd. | Depth mapping using projected patterns |
EP2162059B1 (en) | 2007-06-12 | 2021-01-13 | Sotera Wireless, Inc. | Vital sign monitor and method for measuring blood pressure using optical, electrical, and pressure waveforms |
US8602997B2 (en) | 2007-06-12 | 2013-12-10 | Sotera Wireless, Inc. | Body-worn system for measuring continuous non-invasive blood pressure (cNIBP) |
US8310336B2 (en) | 2008-10-10 | 2012-11-13 | Masimo Corporation | Systems and methods for storing, analyzing, retrieving and displaying streaming medical data |
US20090156932A1 (en) | 2007-12-13 | 2009-06-18 | Board Of Trustees Of The University Of Arkansas | Device and method for in vivo flow cytometry using the detection of photoacoustic waves |
WO2009093228A2 (en) | 2008-01-21 | 2009-07-30 | Prime Sense Ltd. | Optical designs for zero order reduction |
US8384997B2 (en) | 2008-01-21 | 2013-02-26 | Primesense Ltd | Optical pattern projection |
EP2252426A4 (en) | 2008-03-21 | 2014-08-06 | Imra America Inc | Laser-based material processing methods and systems |
JP5040776B2 (en) | 2008-03-31 | 2012-10-03 | アイシン精機株式会社 | Imaging device |
SG156540A1 (en) | 2008-04-16 | 2009-11-26 | Glucostats System Pte Ltd | Method and system for measuring a composition in the blood stream of a patient |
GB0807611D0 (en) | 2008-04-25 | 2008-06-04 | Univ Manchester | Dental imaging and apparatus thereof |
US8456517B2 (en) | 2008-07-09 | 2013-06-04 | Primesense Ltd. | Integrated processor for 3D mapping |
US8158175B2 (en) | 2008-08-28 | 2012-04-17 | Frito-Lay North America, Inc. | Method for real time measurement of acrylamide in a food product |
WO2010056973A1 (en) | 2008-11-14 | 2010-05-20 | Nonin Medical, Inc. | Optical sensor path selection |
WO2010065067A1 (en) * | 2008-11-20 | 2010-06-10 | Bodymedia, Inc. | Method and apparatus for determining critical care parameters |
EP2400884B1 (en) | 2009-02-25 | 2018-03-07 | Valencell, Inc. | Light-guiding devices and monitoring devices incorporating same |
US8788002B2 (en) | 2009-02-25 | 2014-07-22 | Valencell, Inc. | Light-guiding devices and monitoring devices incorporating same |
DE102010012987A1 (en) * | 2009-03-31 | 2010-10-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method for attaching optical transmission element on e.g. finger nail, of body of sportsman for determining e.g. glucose content of blood, involves attaching optical transmission element and optical detector element to parts of body |
US8768016B2 (en) | 2009-06-19 | 2014-07-01 | Carestream Health, Inc. | Method for quantifying caries |
US20110040197A1 (en) | 2009-07-20 | 2011-02-17 | Masimo Corporation | Wireless patient monitoring system |
US20110208015A1 (en) | 2009-07-20 | 2011-08-25 | Masimo Corporation | Wireless patient monitoring system |
JP5852305B2 (en) | 2009-10-28 | 2016-02-03 | カール ツァイス マイクロスコピー ゲーエムベーハーCarl Zeiss Microscopy Gmbh | Microscopy and microscope with improved resolution |
KR101431769B1 (en) | 2009-12-10 | 2014-08-20 | 삼성전자주식회사 | Centrifugal Microfluidic structure for measuring the glycated hemoglobin, centrifugal microfluidic device for measuring the glycated hemoglobin and method for measuring the glycated hemoglobin |
US8320621B2 (en) | 2009-12-21 | 2012-11-27 | Microsoft Corporation | Depth projector system with integrated VCSEL array |
US20110188054A1 (en) | 2010-02-02 | 2011-08-04 | Primesense Ltd | Integrated photonics module for optical projection |
EP2388615B1 (en) | 2010-05-17 | 2020-03-18 | Velodyne LiDAR, Inc. | High definition lidar system |
US20110292376A1 (en) | 2010-05-26 | 2011-12-01 | Kukushkin Igor V | Apparatus and method for detecting raman and photoluminescence spectra of a substance |
US9326712B1 (en) | 2010-06-02 | 2016-05-03 | Masimo Corporation | Opticoustic sensor |
US8509882B2 (en) | 2010-06-08 | 2013-08-13 | Alivecor, Inc. | Heart monitoring system usable with a smartphone or computer |
CN101849821B (en) | 2010-06-13 | 2012-07-04 | 华中科技大学 | Optical fiber near-infrared spectrometer |
US8587771B2 (en) | 2010-07-16 | 2013-11-19 | Microsoft Corporation | Method and system for multi-phase dynamic calibration of three-dimensional (3D) sensors in a time-of-flight system |
US9940682B2 (en) | 2010-08-11 | 2018-04-10 | Nike, Inc. | Athletic activity user experience and environment |
US8649838B2 (en) | 2010-09-22 | 2014-02-11 | Covidien Lp | Wavelength switching for pulse oximetry |
US8760517B2 (en) | 2010-09-27 | 2014-06-24 | Apple Inc. | Polarized images for security |
US9167991B2 (en) | 2010-09-30 | 2015-10-27 | Fitbit, Inc. | Portable monitoring devices and methods of operating same |
US9675250B2 (en) | 2010-11-01 | 2017-06-13 | Oxirate, Inc. | System and method for measurement of vital signs of a human |
US9451885B2 (en) | 2010-12-22 | 2016-09-27 | University of Pittsburgh—of the Commonwealth System of Higher Education | Depth-selective fiber-optic probe |
US8475367B1 (en) | 2011-01-09 | 2013-07-02 | Fitbit, Inc. | Biometric monitoring device having a body weight sensor, and methods of operating same |
US8888701B2 (en) | 2011-01-27 | 2014-11-18 | Valencell, Inc. | Apparatus and methods for monitoring physiological data during environmental interference |
AU2011358630A1 (en) | 2011-02-09 | 2013-09-12 | Massachusetts Institute Of Technology | Wearable vital signs monitor |
JP5847205B2 (en) | 2011-02-25 | 2016-01-20 | トライライト テクノロジーズ ゲゼルシャフト ミット ベシュレンクテル ハフツングTriLite Technologies GmbH | Display device with movable elements for high resolution and / or 3D effect |
US20130281795A1 (en) | 2012-04-18 | 2013-10-24 | The Board Of Trustees Of The University Of Arkansas | Wearable remote electrophysiological monitoring system |
WO2012135952A1 (en) | 2011-04-05 | 2012-10-11 | The Governing Council Of The University Of Toronto | Systems and methods for thermophotonic dynamic imaging |
US8619049B2 (en) | 2011-05-17 | 2013-12-31 | Microsoft Corporation | Monitoring interactions between two or more objects within an environment |
ES2415555B2 (en) | 2011-05-20 | 2014-07-09 | Medlumics, S.L. | SWEEP DEVICE FOR LOW COHERENCE INTERFEROMETRY. |
US8430310B1 (en) | 2011-05-24 | 2013-04-30 | Google Inc. | Wireless directional identification and verification using wearable electronic devices |
US20120310062A1 (en) | 2011-05-31 | 2012-12-06 | Nellcor Puritan Bennett Llc | Photon density wave based determination of physiological blood parameters |
US20120316455A1 (en) | 2011-06-10 | 2012-12-13 | Aliphcom | Wearable device and platform for sensory input |
WO2013012938A1 (en) | 2011-07-18 | 2013-01-24 | Massive Health, Inc. | Health meter |
US8749796B2 (en) | 2011-08-09 | 2014-06-10 | Primesense Ltd. | Projectors of structured light |
US8755871B2 (en) | 2011-11-30 | 2014-06-17 | Covidien Lp | Systems and methods for detecting arrhythmia from a physiological signal |
US10123711B2 (en) | 2012-01-10 | 2018-11-13 | Maxim Integrated Products, Inc. | Heart rate and blood oxygen monitoring system |
US9179876B2 (en) | 2012-04-30 | 2015-11-10 | Nellcor Puritan Bennett Ireland | Systems and methods for identifying portions of a physiological signal usable for determining physiological information |
US20130303921A1 (en) | 2012-05-11 | 2013-11-14 | Hong Kong Applied Science and Technology Research Institute Company Limited | System and Method for Measurement of Physiological Data with Light Modulation |
US9241676B2 (en) | 2012-05-31 | 2016-01-26 | Covidien Lp | Methods and systems for power optimization in a medical device |
US8954135B2 (en) | 2012-06-22 | 2015-02-10 | Fitbit, Inc. | Portable biometric monitoring devices and methods of operating same |
US8948832B2 (en) | 2012-06-22 | 2015-02-03 | Fitbit, Inc. | Wearable heart rate monitor |
US9005129B2 (en) | 2012-06-22 | 2015-04-14 | Fitbit, Inc. | Wearable heart rate monitor |
US9877650B2 (en) | 2012-09-20 | 2018-01-30 | Masimo Corporation | Physiological monitor with mobile computing device connectivity |
DE102013225676B4 (en) | 2012-12-17 | 2018-06-07 | pmdtechnologies ag | Photoflash camera with motion detection |
RU2015129486A (en) | 2012-12-19 | 2017-01-25 | Конинклейке Филипс Н.В. | FLUORESCENT METHOD AND TIME RESOLUTION DETECTION SYSTEM IN THE FREQUENCY AREA |
WO2014105520A1 (en) | 2012-12-31 | 2014-07-03 | Omni Medsci, Inc. | Near-infrared lasers for non-invasive monitoring of glucose, ketones, hba1c, and other blood constituents |
US9164032B2 (en) | 2012-12-31 | 2015-10-20 | Omni Medsci, Inc. | Short-wave infrared super-continuum lasers for detecting counterfeit or illicit drugs and pharmaceutical process control |
EP3184038B1 (en) | 2012-12-31 | 2019-02-20 | Omni MedSci, Inc. | Mouth guard with short-wave infrared super-continuum lasers for early detection of dental caries |
US9993159B2 (en) | 2012-12-31 | 2018-06-12 | Omni Medsci, Inc. | Near-infrared super-continuum lasers for early detection of breast and other cancers |
US9110163B2 (en) | 2013-06-14 | 2015-08-18 | Microsoft Technology Licensing, Llc | Lidar-based classification of object movement |
WO2015038561A1 (en) | 2013-09-11 | 2015-03-19 | Tiger Optics, Llc | Cavity-enhanced frequency comb spectroscopy system employing a prism cavity |
WO2015084376A1 (en) | 2013-12-05 | 2015-06-11 | Apple Inc. | Wearable multi-modal physiological sensing sysem |
-
2013
- 2013-12-17 WO PCT/US2013/075700 patent/WO2014105520A1/en active Application Filing
- 2013-12-17 EP EP13867874.3A patent/EP2938259A4/en not_active Withdrawn
- 2013-12-17 EP EP17155541.0A patent/EP3181048A1/en not_active Withdrawn
- 2013-12-17 CA CA2895969A patent/CA2895969A1/en not_active Abandoned
-
2018
- 2018-02-04 US US15/888,052 patent/US10136819B2/en not_active Expired - Fee Related
- 2018-07-08 US US16/029,611 patent/US10201283B2/en active Active - Reinstated
-
2019
- 2019-02-11 US US16/272,069 patent/US20190167114A1/en not_active Abandoned
- 2019-07-09 US US16/506,885 patent/US10517484B2/en active Active
- 2019-12-20 US US16/722,188 patent/US10820807B2/en active Active
-
2020
- 2020-10-23 US US17/078,771 patent/US11160455B2/en active Active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020257861A1 (en) * | 2019-06-27 | 2020-12-30 | Macquarie University | Diagnosis and monitoring of neurodegenerative diseases |
Also Published As
Publication number | Publication date |
---|---|
EP2938259A4 (en) | 2016-08-17 |
US10517484B2 (en) | 2019-12-31 |
US20180153410A1 (en) | 2018-06-07 |
CA2895969A1 (en) | 2014-07-03 |
US10201283B2 (en) | 2019-02-12 |
US20200281477A1 (en) | 2020-09-10 |
US20180317776A1 (en) | 2018-11-08 |
WO2014105520A1 (en) | 2014-07-03 |
US20190328235A1 (en) | 2019-10-31 |
US11160455B2 (en) | 2021-11-02 |
EP2938259A1 (en) | 2015-11-04 |
EP3181048A1 (en) | 2017-06-21 |
US20210038083A1 (en) | 2021-02-11 |
US10136819B2 (en) | 2018-11-27 |
US10820807B2 (en) | 2020-11-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10201283B2 (en) | Near-infrared laser diodes used in imaging applications | |
US9885698B2 (en) | Near-infrared lasers for non-invasive monitoring of glucose, ketones, HbA1C, and other blood constituents | |
US10874304B2 (en) | Semiconductor source based near infrared measurement device with improved signal-to-noise ratio | |
US11353440B2 (en) | Time-of-flight physiological measurements and cloud services | |
US11109761B2 (en) | High signal-to-noise ratio light spectroscopy of tissue | |
US11896346B2 (en) | Short-wave infrared sensor for identifying based on water content | |
US20240180428A1 (en) | Wearable devices comprising semiconductor diode light sources with improved signal-to-noise ratio |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |