SE537342C2 - Insertable probe for heat treatment of tissue - Google Patents

Insertable probe for heat treatment of tissue Download PDF

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Publication number
SE537342C2
SE537342C2 SE1050655A SE1050655A SE537342C2 SE 537342 C2 SE537342 C2 SE 537342C2 SE 1050655 A SE1050655 A SE 1050655A SE 1050655 A SE1050655 A SE 1050655A SE 537342 C2 SE537342 C2 SE 537342C2
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Sweden
Prior art keywords
probe tip
probe
light
refractive index
end cap
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SE1050655A
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Swedish (sv)
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SE1050655A1 (en
Inventor
Pär Håkan Henriksson
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Clinical Laserthermia Systems Ab
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Priority to SE1050655A priority Critical patent/SE537342C2/en
Priority to PCT/EP2011/060384 priority patent/WO2011161126A1/en
Publication of SE1050655A1 publication Critical patent/SE1050655A1/en
Publication of SE537342C2 publication Critical patent/SE537342C2/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/06—Radiation therapy using light
    • A61N5/0613—Apparatus adapted for a specific treatment
    • A61N5/0625—Warming the body, e.g. hyperthermia treatment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F7/00—Heating or cooling appliances for medical or therapeutic treatment of the human body
    • A61F7/12—Devices for heating or cooling internal body cavities
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B2018/2255—Optical elements at the distal end of probe tips
    • A61B2018/2261—Optical elements at the distal end of probe tips with scattering, diffusion or dispersion of light
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/18—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves
    • A61B18/20—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser
    • A61B18/22—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by applying electromagnetic radiation, e.g. microwaves using laser the beam being directed along or through a flexible conduit, e.g. an optical fibre; Couplings or hand-pieces therefor
    • A61B2018/2255—Optical elements at the distal end of probe tips
    • A61B2018/2272—Optical elements at the distal end of probe tips with reflective or refractive surfaces for deflecting the beam
    • A61B2018/2277—Optical elements at the distal end of probe tips with reflective or refractive surfaces for deflecting the beam with refractive surfaces
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/06—Radiation therapy using light
    • A61N2005/063—Radiation therapy using light comprising light transmitting means, e.g. optical fibres
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/06—Radiation therapy using light
    • A61N2005/0658—Radiation therapy using light characterised by the wavelength of light used
    • A61N2005/0659—Radiation therapy using light characterised by the wavelength of light used infrared
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/06—Radiation therapy using light
    • A61N5/067—Radiation therapy using light using laser light

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Surgery (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Otolaryngology (AREA)
  • Pathology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Thermal Sciences (AREA)
  • Vascular Medicine (AREA)
  • Laser Surgery Devices (AREA)
  • Radiation-Therapy Devices (AREA)

Abstract

16 Abstract The present invention relates to probe tips for laser light en1itting probes. Each probe tipconiprises a probe tip body made of a first material With a first refractive index, Which probe tip body has a sn1ooth outer surface and contains internal light diffusing means. Figure 2b)

Description

Insertable probes Field of the Invention The present invention relates to insertable probes for using in the therrnal treatment of tissue using electromagnetic radiation.
Background art The treatment of tissues by electromagnetic radiation in the form of laser beams is known.Typically a laser source produces a beam of laser light Which is fed via a Waveguide, forexample an optical f1bre, though the body of an insertable probe to a light-transmissive probetip from Which the light can leave the probe and heat up the tissue in the vicinity of the probetip. Different types of probe tips are known Which can have the purpose of diffusing the lightleaving the probe tip so that the energy is more or less evenly distributed into the surroundingtissue. EP 404968 describes a probe With a tapered light transmissive tip Which is providedWith a surface Which scatters the exiting laser light. The light-scattering surface can beachieved by making the surface rough or by attaching light-scattering particles made of a material having a higher refractive index than that of the material of the tip to the surface.
A problem With such light-scattering probe tips is that in practice the rough surface or light-scattering particles may cause the surrounding tissue to adhere to the surface. The adheringtissue can negate the light-scattering effect of the rough surface or light-scattering particlesand cause the laser energy to be concentrated into the area Where the tissue is attached leading to undesirable overheating of the tissue so-called “hot spots”.
Summary of the invention An object of the present invention is to provide probes Which overcome the problems of the prior art probe tips.
The present invention achieves the above object by providing a probe With a probe tip Whichreduce the risk that tissue can adhere to the probe tip and Which also, in the event that tissue does adhere to the probe tip, reduce the risk that local overheating of the tissue occurs.
In one enibodinient of the present invention this is achieved by providing a probe tip which isprovided with means able to diffuse a laser beani and which further has a sniooth surface in contact with the tissue being treated.
In a further enibodinient of the present invention this is achieved by providing a probe tip with nieans for indicating when a control temperature has been achieved.
Description of the figures Figure la) shows scheniatically a side view of a prior art probe with a cylindrical probe tip;Figure lb) shows scheniatically a side view of a prior art probe with a tapered probe tip;Figure lc) shows scheniatically a side view of a prior art probe with a rounded probe tip;Figure 2a) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a first enibodinient of the present invention; Figure 2b) shows scheniatically an enlarged perspective view of the probe tip of figure 2a);Figure 3a) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a second enibodinient of the present invention; Figure 3b) shows scheniatically an enlarged perspective view of the probe tip of figure 3a);Figure 4a) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a third enibodinient of the present invention; Figure 4b) shows scheniatically an enlarged perspective view of the probe tip of figure 4a);Figure Sa) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a fourth enibodinient of the present invention; and Figure 5b) shows scheniatically an enlarged perspective view of the probe tip of figure 5a):Figure 6a) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a fifth enibodinient of the present invention; and Figure 6b) shows scheniatically an enlarged perspective view of the probe tip of figure 6a),Figure 7a) shows scheniatically a side view of a probe with a cylindrical probe tip inaccordance with a sixth enibodinient of the present invention; and, Figure 7b) shows scheniatically an enlarged perspective view of the probe tip of figure 7a).
Description of the invention Figures la), lb) and lc) show examples of prior art insertable probes with different shapes of probe tips.
Figure la) shows a probe la with a cylindrical body 3a surrounding a waveguide 5a. Theproximal end 2a of the waveguide 5a is connectable to a source of laser radiation 7a. Thedistal end 4a of waveguide 5a leads to a probe tip 9a attached to the distal end 6a ofcylindrical body Sa. Probe tip 9a is made of a laser light transmissive material such as quartzor, sapphire. Probe tip 9a is cylindrical and the surface 1 la of it is roughened to give a matt,frosted surface structure which acts as a light diffuser. When a beam of laser radiation isemitted from the laser radiation source 7a it travels though the waveguide 5a to probe tip 9awhereupon it is refracted by the rough surface of probe tip 9a and emitted from the probe tip in many directions, thereby producing a diffuse laser light which covers a large area.
Figure lb) shows a probe lb with a cylindrical body 3b surrounding a waveguide 5b. Theproximal end 2b of the waveguide 5b is connectable to a source of laser radiation 7b. Thedistal end 4b of waveguide 5b leads to a probe tip 9b attached to the distal end 6b ofcylindrical body 3b. Probe tip 9b is made of a laser light transmissive material such as quartz,or sapphire. Probe tip 9b is conical with the widest end 13b of the cone nearest the distal end4b of the waveguide and the surface 11b of it is roughened to give a matt, frosted surface structure which acts as a light diffuser.
Figure lc) shows a probe 1c with a cylindrical body 3c surrounding a waveguide 5c. Theproximal end 2c of the waveguide 5c is connectable to a source of laser radiation 7c. Thedistal end 4c of waveguide 5c leads to a probe tip 9c attached to the distal end 6c ofcylindrical body 3c. Probe tip 9c is made of a laser light transmissive material such as quartzor sapphire. Probe tip 9c is hemi-spherical with the flat surface 13c of the hemisphere nearestthe distal end 4c of the waveguide and the surface llc of the hemisphere intended to be in contact with tissue is roughened to give a matt, frosted surface structure which acts as a lightdiffuser.
Figures 2a) and 2b) shows a first embodiment of a probe 201 with a probe tip 209 inaccordance with the present invention, where figure 2b) is an enlarged view of the probe tipshown in figure 2a). Probe 201 has an elongated body 203 surrounding a waveguide 205. The proximal end 202 of the waveguide 205 is connectable to a source of laser radiation 207.
Preferably the laser radiation is in the form of a beam with a wavelength between 800 nm and1300 nm, more preferably between 1000 and 1100 nm and most preferably 1060 nm. Thedistal end 204 of waveguide 205 leads to a substantially transparent probe tip 209 attached tothe distal end 206 of elongated body 203. Probe tip 209 is made of laser light transmissivematerials such as quartz, sapphire, polymers, glass or the like. Probe tip 209 is cylindricalwith a diameter Dpt which is preferably the same as the outer diameter Dtb of elongated body203 (and therefore Dpt is greater than diameter Dwg of waveguide 205) in order to allow thejoin between the probe tip and probe body to pass through tissue without catching on it.Probe tip 209 has a smooth and/or low friction surface 211 which prevents tissue adhering toit. The term “smooth” in this application the means that a surface is substantially free ofscratches or defects which would cause light passing through it to be diffused, in particularthat preferably the surface has a surface roughness (Ra) of less than 25 um, more preferablyan Ra of less than 10 um, even more preferably an Ra of less than 1 um and most preferably aRa of less than 0.1 um. Probe tip 209 is made of two or more materials with differentrefractive indexes. Probe tip 209 comprises intemal light diffusion means in the form of anelongated probe tip body 217 and a conical probe tip proximal portion 215. Proximal portion215 is of length Lcpp with the widest end 213 (preferably of diameter Dpt) of the conicalportion 215 nearest the distal end 204 of the waveguide. Proximal portion 215 is made of amaterial with a first refractive index. An elongated probe tip body 217 of length Lptb (whichin this embodiment is shown as being substantially equal to Lcpp but may conceivably belonger than Lcpp) which has a longitudinally extending concave cavity 218, of the same sizeand shape as proximal portion 215, is mounted on, and encloses, proximal portion 215.Elongated probe tip body 217 is made of a material with a second refractive index which isnot the same as the first refractive index. The second refractive index can be lower than thefirst refractive index. Altematively the second refractive index can be higher than the firstrefractive index. The use of two materials with different refractive indexes means that thecontact surface between the two materials acts as to reflect some of the incident light and totransmit some of the incident light. This causes some of the incoming laser beam A, which ishighly collimated, to be intemally reflected before leaving the probe tip 209. Differentportions of the laser beam will be reflected a different number of times and will leave theprobe tip at different positions which causes the laser light leaving the probe tip to be diffuse.Altematively or additionally the outer surface of conical proximal portion 215 and/or theinner surface of elongated probe tip body may be partly mirrored to cause intemal reflection in the probe tip. The total surface area of the cylindrical surface of the transparent portion probe tip Which is intended to emit a portion of the diffuse laser beam has a surface area of Xsquare millimetres and the, in this embodiment Circular, surface area of the distal end of probetip 209 Which is intended to emit the remaining portion of the diffuse laser beam (such anemitting area may be less than the total surface area of the distal end of probe tip 209 - seebelow for an example Where an end cap is used to reduce the surface area of the emitting area)has a surface area of Y square millimetres. In a preferred example of this embodiment of thepresent invention it is intended that the incoming laser beam is emitted as a diffuse beam Withsubstantially equal intensity (and thus substantially equal Warming effect) in the longitudinaldirection and lateral directions of the probe tip. In order to achieve this the angle of the slopeof the side of the conical proximal portion 215, its length, refractive index and any mirroringof the probe tip are selected so that the proportion of diffused laser light Which is emittedthrough the end surface of the probe tip is Y/(X + Y) of the total emitted light. The remainingemitted light X/ (X +Y) is intended to be emitted through the transparent cylindrical surface ofthe probe tip.
While it is preferable that the intensity of the emitted diffused light is substantially the sameover the Whole of the emitting surface, it is also possible to have some variations in theintensity of the distributed of light Without causing hot spots Where the tissue is overheated, asonce the tissue in the vicinity of the probe starts to heat up due to the diffused laser light, anytemperature differences in the heated tissue Will tend to be reduced by conduction of heat energy from the hotter areas to cooler areas.
Optionally the distal end of probe tip 209 may be covered by an end cap 219 of diameter DecWhich is substantially the same as that of the probe tip body 217 and a length Which is lessthan that of the probe tip body Lptb. The surface of end cap 219 Which faces the Waveguide ispreferably arranged to reflect light -this can be achieved by surface treatment so that it has amirror finish or by making end cap 219 of a material Which has a different refractive index tothe material used for the probe tip body 217. The reflective surface end cap reflects light backinto the probe tip body Which helps it become more evenly dispersed and at the same timeprevents light being emitted in the axial direction of the probe tip - something Which isdesirable in some applications. HoWever, in the event that it is desirable that some light beemitted in the axial direction of the probe tip then the end cap can be omitted or, as shoWn by dotted lines, a light-transmissive portion 221 of the end cap (in this example the centre portion but any other portion is also conceivable, e. g. an annular portion or one or more segments) can be made non-reflective or less than 100% reflective to allow light to pass through it.
Figures 3a) and 3b) shows a second embodiment of a probe 301 with a substantiallytransparent probe tip 309 in accordance with the present inVention, where figure 3b) is anenlarged View of the probe tip shown in figure 3a). Probe 301 has an elongated body 303surrounding a waveguide 305. The proximal end 302 of the waveguide 305 is connectable to asource of laser radiation 307. The distal end 304 of waveguide 305 leads to a probe tip 309attached to the distal end 306 of elongated body 303. Probe tip 309 is made of laser lighttransmissive materials such as quartz, sapphire, polymers, glass or the like. Probe tip 309 iscylindrical with a diameter Dpt which is preferably the same as the outer diameter Dtb ofelongated body 303 (and therefore Dpt is greater than diameter Dwg of waveguide 305) inorder to allow the join between the probe tip and probe body to pass though tissue withoutcatching on it. Probe tip 309 has a smooth or low-friction surface 311 which preVents tissueadhering to it. Probe tip 309 is made of two or more materials with different refractiveindexes. Probe tip 309 comprises intemal light diffusing means comprising a conical distalportion 316 and an elongated probe tip body 317. Conical distal portion 316 has length Lcdpwith the widest end 313 (preferably of diameter Dpt) of the conical portion 316 furthest fromthe distal end 304 of the waveguide. Conical distal portion 316 is made of a material with afirst refractive index. A elongated probe tip body 317 of length Lptb (which may substantiallyequal to Lcdp but in this embodiment is shown to be longer than Lcdp) which has alongitudinally extending concaVe caVity 318, of the same size and shape as conical distalportion 316, is mounted on, and encloses, conical distal portion 316. Elongated probe tip body317 is made of a material with a second refractive index which is not the same as the firstrefractive index. The use of two materials with different refractive indexes means that thecontact surface between the two materials acts as a mirror and the incoming laser beam isintemally reflected a plurality of times before leaving the probe tip 309. This causes the laserlight leaving the probe tip to be diffuse. Altematively or additionally the outer surface ofconical distal portion 316 and/or the inner surface of elongated probe tip body may be partly mirrored to cause intemal reflection in the probe tip.
Optionally the distal end of probe tip 309 may be covered by an end cap 319 of diameter Decwhich is substantially the same as that of the probe tip body 317 and a length which is lessthan that of the probe tip body Lptb. The end cap 319 may be part of the intemal laser diffusing means. The surface of end cap 319 which faces the waVeguide is preferablyarranged to reflect light -this can be achieved by surface treatment so that it has a mirrorfinish or by making end cap 319 of a material which has a different refractiVe index to thematerial used for the distal portion 316. The end cap reflects light back into the probe tip bodywhich helps it become more evenly dispersed and at the same time prevents light beingemitted in the axial direction of the probe tip - something which is desirable in someapplications. In the event that it is desirable that some light be emitted in the axial direction ofthe probe tip then the end cap can be omitted or, as shown by dotted lines, a light-transmissiveportion 321 of the end cap (in this example the centre portion but any other portion is alsoconceivable, e. g. an annular portion or one or more segments) can be made non-reflective or less than 100% reflective to allow light to pass through it.
Figures 4a) and 4b) shows a third embodiment of a probe 501 with a substantially transparentprobe tip 509 in accordance with the present invention, where figure 4b) is an enlarged Viewof the probe tip shown in figure 4a). Probe 501 has an elongated body 503 surrounding awaVeguide 505. The proximal end 502 of the waVeguide 505 is connectable to a source oflaser radiation 507. The distal end 504 of waVeguide 505 leads to a probe tip 509 attached tothe distal end 506 of elongated body 503. Probe tip 509 is made of laser light transmissivematerials such as quartz, sapphire, polymers, glass or the like. Probe tip 509 is cylindricalwith a diameter Dpt which is preferably the same as the outer diameter Dtb of elongated body503 (and therefore Dpt is greater than diameter Dwg of waVeguide 505) in order to allow thejoin between the probe tip and probe body to pass though tissue without catching on it. Probetip 509 has a smooth or low-friction surface 511 which prevents tissue adhering to it. Probetip 509 comprises intemal light diffusing means. Probe tip 509 is made of two or morematerials with different refractive indexes. Probe tip 509 comprises a rounded (shown here assubstantially hemispherical) proximal portion 515 of length Lcpp with the widest end 513a(preferably of diameter Dpt) of the conical portion 515 closest to the distal end 504 of thewaVeguide and a conical distal portion 516 of length Lcdp with its widest end 513b(preferably of diameter Dpt) furthest away from the distal end 504 of the waVeguide.Rounded proximal portion 515 and conical distal portion 516 may be made of the samematerial with a first refractiVe index or of different materials with different refractive indices.A elongated probe tip body 517 of length Lptb (which may substantially equal to Lcpp +Lcdp but in this embodiment is shown to be longer than Lcpp + Lcdp) which has two longitudinally extending concave cavities 518a and 518b, of the same size and shape respectively as hemispherical proximal portion 515 and conical distal portion 516, is mountedon, and encloses, hemispherical proximal portion 515 and conical distal portion 516.Elongated probe tip body 517 is made of a material with a refractive index which is not thesame as that of the material(s) used for the rounded proximal and conical distal portions 515,516. The use of materials with different refractive indexes means that the contact surfacebetween the materials acts as a partial mirror or light deflecting surface and the incoming laserbeam is intemally reflected a plurality of times before leaving the probe tip 509. This causesthe laser light leaving the probe tip to be diffuse. Altematively or additionally the outersurface of rounded proximal portion 515 and/or conical distal portion 516 and/or the innersurface of elongated probe tip body may be partly mirrored to cause intemal reflection in the probe tip.
Optionally the distal end of probe tip 509 may be covered by an end cap 519 of diameter Decwhich is substantially the same as that of the probe tip body 517 and a length which is lessthan that of the probe tip body Lptb. The surface of end cap 519 which faces the waveguide ispreferably arranged to reflect light -this can be achieved by surface treatment so that it has amirror finish or by making end cap 519 of a material which has a different refractive index tothe material used for the distal portion 516. The end cap reflects light back into the probe tipbody which helps it become more evenly dispersed and at the same time prevents light beingemitted in the axial direction of the probe tip - something which is desirable in someapplications. In the event that it is desirable that some light be emitted in the axial direction ofthe probe tip then the end cap can be omitted or, as shown by dotted lines, a light-transmissiveportion 521 of the end cap (in this example the centre portion but any other portion is alsoconceivable, e.g. an annular portion or one or more segments) can be made non-reflective or less than 100% reflective to allow light to pass through it.
While the invention has been illustrate with examples where 515 has a rounded shape and 516has a conical shape it is conceivable that both 515 and 516 may have a rounded shape or 515 a conical shape and 516 a rounded shape.
Figures 5a) and 5b) shows a fourth embodiment of a probe 601 with a substantiallytransparent probe tip 609 in accordance with the present invention, where figure 5b) is anenlarged view of the probe tip shown in figure 5a). Probe 601 has an elongated body 603 surrounding a waveguide 605. The proximal end 602 of the waveguide 605 is connectable to a source of laser radiation 607. The distal end 604 of waveguide 605 leads to a probe tip 609attached to the distal end 606 of elongated body 603. Probe tip 609 is made of laser lighttransmissive materials such as quartz, sapphire, polymers, glass or the like and contains laserlight diffusing means. Probe tip 609 is cylindrical with a diameter Dpt which is preferably thesame as the outer diameter Dtb of elongated body 603 (and therefore Dpt is greater thandiameter Dwg of waveguide 605) in order to allow the join between the probe tip and probebody to pass though tissue without catching on it. Probe tip 609 has a smooth or low-frictionsurface 6ll which prevents tissue adhering to it. Probe tip 609 comprises a ho llow tubularprobe tip body 6l7 of length Lptb and inner diameter Di made of a material with a first refractive index.
The distal end of probe tip 609 is covered by an end cap 619 of diameter Dec which issubstantially the same as that of the probe tip body 6l7 and a length which is less than that ofthe probe tip body Lptb. The surface of end cap 619 which faces away from the waveguide ispreferably arranged to reflect light -this can be achieved by surface treatment so that it has amirror finish or by making end cap 619 of a material which has a different refractive index tothe material used for the probe tip body 6l7 and, as mentioned below, different to that of thefirst material which fills ho llow probe tip body 6l7. The material used for end cap 619 isluminescent (i.e. fluorescent or phosphorescent) so that when excited by incident laser light ofa certain wavelength Å,- it emits light at emitted wavelength k., and its reflective surfacereflects some of this light back into the probe tip body and to wave guide 605. Waveguide605 guides this emitted light to a light detector 625 which produces a signal which isdependent on the strength of emitted light detected by it and the wavelength of the reflected light k., may depend on the surrounding temperature.
Hollow probe tip body 6l7 is substantially filed with a first material 627 with a melting pointtemperature which is the same as a desired temperature. Preferably the desired temperature isa temperature that is over normal body temperature and is also a temperature at which adesired effect on surrounding tissue takes place. For example, the melting point temperaturecan be set at a temperature which would be expected to cause tissue at a distance of l -20 mmmore preferably l0 mm from the surface of the probe tip body to achieve a temperature atwhich damage to cells occurs. Preferably this is a steady-state temperature between 42° C and48° C, more preferably a steady-state temperature of between 43° C and 47° C, and even more preferably between 45° C and 46° C. This melting point temperature is dependent on therrnal conductivity of the tissue that the probe tip body is inserted into and it may need to beas high as 98° C to achieve the necessary steady-state temperature at a distance from theprobe tip body. However in order to avoid damaging a patient the melting point temperaturepreferably be low enough to prevent boiling or burning of the tissue in contact With the probetip body. This first material contains light-blocking material 629 Which prevents light passingthrough the particles or reduces the amount of light Which passes through the particle. Theparticles can be (semi-)light-reflectingor (semi-)light-absorbing particles in the forrn of grainsor pieces of foil or nanoWires. The light-blocking material causes incident laser light to bereflected and/or absorbed and as the material is randomly distributed the laser light Will bereflected randomly Which Will result in it becoming diffused. When the probe is below themelting point of the first material the light-blocking material is immobilised and the amountof light Which reaches the luminescent end cap is substantially constant if the incident laserlight is kept at constant power. The light-blocking material prevents some of the laser lightfrom reaching the luminescent material and also prevents some of the light emitted from theend cap from reaching the light detector. This means that the amount of light Which is emittedfrom the end cap at k., and reflected back into the probe tip body and to Wave guide 605 issubstantially constant and therefore the signal from light detector 625 is substantiallyconstant. However When the probe is heated and the first material melts then the light-blocking material is able to move about in the melted first material and both the amount oflaser light reaching the end cap and the amount of light emitted from the end cap reaching thelight detector 625 Will change as the light-blocking material moves. By monitoring changes inthe signal from the light detector it is possible to detect When the first material melts andthereby determine the temperature in the probe is the same as, or higher than, the meltingpoint temperature. This information can be used in a feedback system to control thetemperature of the probe tip body, for example by reducing the intensity of the incident laserlight When melting of the first material has been detected, and increasing the intensity When solidification of the first material has been detected.
It is conceivable to provide a probe tip body With two or more sealed compartments arrangedalong the axial direction of the probe tip body and to provide light-blocking material and afirst material With a first melting point temperature e.g. 50° C in a first compartment, light-blocking material and a second material With a second melting point temperature, e. g. 90° Cin a second compartment and light-blocking material and, subsequent materials With different melting point temperatures in subsequent compartments. This Will lead to one change in the 11 amount of reflected light once the probe tip has passed the first lowest melting pointtemperature and further changes in the amount of reflected light when the temperature of theprobe tip passes subsequent melting point temperatures. These changes in the amount ofreflected light can be used to determine if the temperature of the probe tip body has passed the predeterrnined melting point temperatures.
Other embodiments of probe tips provided with material which melts at a predeterrninedtemperature are also possible. For example, a probe tip may be provided with a solid roundedor conical distal portion (a conical distal portion is shown in dotted lines as 616 by way ofexample) or the solid conical or rounded proximal/distal portions of a probe tip describedabove can be replaced by ho llow conical or rounded probe portions containing a materialwhich melts at a predeterrnined temperature. This material can completely or partly fill thehollow probe portions, any remaining space being filled with a fluid. In place of, or inaddition to, light-blocking material it is also conceivable that the material which melts at apredeterrnined temperature could be opaque when in the solid state and transparent in theliquid state, such as for example, waxes or fats. If an opaque material is used then it will disperse incident laser light and act as an intemal diffuser.
Figure 6a) and 6b) show a fifth embodiment of a probe 701 with a probe tip 709 inaccordance with the present invention, where figure 6b) is an enlarged view of the probe tipshown in figure 6a). Probe 701 is similar to the third embodiment and has an elongated body703 surrounding a waveguide 705. The proximal end 702 of the waveguide 705 isconnectable to a source of laser radiation 707. The distal end 704 of waveguide 705 leads to aprobe tip 709 attached to the distal end 706 of elongated body 703. Probe tip 709 is made oflaser light transmissive materials such as quartz, sapphire, polymers, glass or the like. Probetip 709 is cylindrical with a diameter Dpt which is preferably the same as the outer diameterDtb of elongated body 703 (and therefore Dpt is greater than diameter Dwg of waveguide705) in order to allow the join between the probe tip and probe body to pass though tissuewithout catching on it. Probe tip 709 has a smooth or low-friction surface 711 which preventstissue adhering to it. Probe tip 709 is made of two or more materials with different refractiveindexes. Probe tip 709 comprises a rounded (shown here as substantially hemispherical)proximal portion 715 of length Lcpp with the widest end 713a (preferably of diameter Dpt) ofthe conical portion 715 closest to the distal end 704 of the waveguide and a conical distal portion 716 of length Lcdp with its widest end 713b (preferably of diameter Dpt) furthest 12 away from the distal end 704 of the waveguide. Rounded proximal portion 715 and conicaldistal portion 716 may be made of the same material with a first refractive index or ofdifferent materials with different refractive indices. A elongated probe tip body 717 of lengthLptb (which may substantially equal to Lcpp + Lcdp but in this embodiment is shown to belonger than Lcpp + Lcdp) which has two longitudinally extending concave cavities 718a and718b, of the same size and shape respectively as hemispherical proximal portion 715 andconical distal portion 716, is mounted on, and encloses, hemispherical proximal portion 715and conical distal portion 716. Elongated probe tip body 717 is made of a material with arefractive index which is not the same as that of the material(s) used for the rounded proximaland conical distal portions 715, 716. The use of materials with different refractive indexesmeans that the contact surface between the materials acts as a partial mirror or laser lightdeflecting area and the incoming laser beam is intemally reflected a plurality of times beforeleaving the probe tip 709. This causes the laser light leaving the probe tip to be diffuse.Altematively or additionally the outer surface of rounded proximal portion 715 and/or conicaldistal portion 716 and/or the inner surface of elongated probe tip body may be partly mirrored to cause intemal reflection in the probe tip.
Optionally the distal end of probe tip 709 may be covered by an end cap 719 of diameter Decwhich is substantially the same diameter as that of the probe tip body 717 and a length whichis less than that of the probe tip body Lptb. The surface of end cap 719 which faces thewaveguide is preferably arranged to reflect light - this can be achieved by surface treatmentso that it has a mirror finish or by making end cap 719 of a material which has a differentrefractive index to the material used for the conical distal portion 716 which it is in contactwith. The end cap reflects light back into the probe tip body which helps it become moreevenly dispersed and at the same time prevents light being emitted in the axial direction of theprobe tip - something which is desirable in some applications. In the event that it is desirablethat some light be emitted in the axial direction of the probe tip then the end cap can beomitted or, as shown by dotted lines, a light-transmissive portion 721 of the end cap (in thisexample the centre portion but any other portion is also conceivable, e.g. an annular portion orone or more segments) can be made non-reflective or less than 100% reflective to allow light to pass through it.
Additionally the distal end of probe tip 709, or end cap 719, if present is provided with electrical temperature sensor such as a therrnistor 731 which produces a signal dependent on 13 the temperature in its vicinity and which signal is sent along a conductor 732 to a temperaturemonitoring and/or displaying means 734. Preferably each temperature sensor has a diameterof less than 0.5 mm or, if it has a quadratic shape, it has no dimension which is greater than0.5 mm It is of course possible to attach such an electrical temperature sensor to anyembodiment of the present invention. Preferably each electrical temperature sensor is shieldedfrom direct exposure to the laser light in order to prevent the direct laser light from Warming the temperature sensor.
Additionally it is possible to provide any probe in accordance with the present invention withone or more additional electrical temperature sensors 733, 735 and conductors 736, 738 asshown by dotted lines. The use of additional temperature sensors provides more precisetemperature sensing and allows therrnal mapping of the temperature distribution in the targetarea. Preferably each temperature sensor is positioned 5-15 mm, more preferably 8-12 mm, in the axial direction of the probe from any neighbouring sensor.
In the event that it is required to measure the impedance or other electrical property of thetissue surrounding the probe, a probe in accordance with the present invention can beprovided with one or more electrically conducting surfaces 741, 743, 745 (shown by dottedlines) each connected by its own conductor 751, 753, 755 (shown by dotted lines) to animpedance sensing circuit 761 (shown by dotted lines). Preferably an electrically conductingsurface can be in therrnal contact with an electrical temperature sensor, such as electricallyconducting surface 733 and electrical temperature sensor 743, in order to make it possible todetermine the temperature at which the impedance or other electrical property reading was measured.
Figures 7a) and 7b) show an embodiment of the invention similar to that shown in figures 6a)and 6b). The conductors 751 753, 755 are opaque and cause shadowing, i.e. they prevent laserlight that is leaving the probe tip from reaching the tissue which lies in their shadow or theyattenuate the laser light. In order to prevent this shadowing from affecting the treatment of thetissue the conductors can be arranged in spirals around the probe so that the shadowing isdistributed around the probe and not concentrated into one area. Preferably the conductors areequally spaced around the circumference of the probe, e.g. if there are 2 conductors then theyare can be spaced at intervals of 180°, if there are 4 conductors then they can be spaced at intervals of 90°. Preferably the spirals are wound in the same direction and with the same 14 pitch so that the conductors are mutually parallel. Such an arrangement of conductors can be used as appropriate With any embodiment of the present invention.
Typically the diameter Dpt of a probe tip body in accordance With the present inVentionpreferably Will be less than 5 mm and more preferably is less than 3 mm. The length Lptb ofthe probe tip body Will be preferably be less than 15mm and more preferably is less than orequal to 10mm.The end cap of a probe tip body preferably Will be less than 2 mm thick and more preferably is less than 1 mm thick.
While the inVention has been illustrate With examples of rotationally symmetrical probe tipproximal and distal portions it is conceiVable to have non-symmetrical or irregular shapedprobe tip proximal and distal portions in order to produce a desired special diffusion pattem.It is also conceiVable to use more than tWo different materials for the probe tip in order toachieve different amounts of intemal reflection as this amount is dependent on Which tWomaterials are present at the interfaces between materials that the laser beam passes through. Itis conceiVable that probe tip components such as proximal portions and/or distal portionsand/or probe bodies may be holloW bodies Which are filled With material, solid, liquid or gasWhich has a further refractive index Which is different to the refractiVe index of the materialWhich the probe tip component is made from. In such cases laser light passing through theWall of the ho llow component Will be refracted twice - once on entering the material of Whichthe Wall is made and once on leaving it. The inVention is not intended top be limited to theembodiments shown but is intended to includes all embodiments covered Within the scope of the appended claims.

Claims (17)

Claims
1. A probe tip for a laser light emitting probe characterised in that it comprises a probe tipbody made of a first material With a first refractive index, Which probe tip body has a smooth outer surface and contains internal light diffusing means.
2. A probe tip in accordance With claim 1 characterised in that said probe tip body is transparent.
3. A probe tip in accordance With any of the previous claims characterised in that said internallaser diffusing means comprises a probe tip distal portion made of a material With a refractive index Which is different to said first refractive index.
4. A probe tip in accordance With any of the previous claims characterised in that said internallaser diffusing means comprises a probe tip proximal portion made of a material With a refractive index Which is different to said first refractive index.
5. A probe tip in accordance With any of the previous claims characterised in that it comprisesa luminescent end cap and a holloW portion containing light-blocking material immobilised ina material With a melting point temperature greater or equal to 42° C and less than or equal to 98° C.
6. A probe tip in accordance With any of claims 1-3 characterised in that it comprises aluminescent end cap and a holloW portion containing light-blocking material immobilised in a material Which is solid below 42° C.
7. A probe tip in accordance With any of claims 1-3 characterised in that it comprises aluminescent end cap and a holloW portion containing light-blocking material immobilised in a material Which is solid below 98° C.
SE1050655A 2010-06-21 2010-06-21 Insertable probe for heat treatment of tissue SE537342C2 (en)

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US9968404B2 (en) * 2013-11-15 2018-05-15 Lumenis Ltd. Optical fiber with smooth tip
CN106659536B (en) * 2014-05-23 2019-11-05 柯惠有限合伙公司 Optical-fiber laser surgical instrument with radiation distribution pattern
EP3161919B1 (en) 2014-06-30 2022-12-28 Societa' Elettrica S.r.l. Device for protecting a direct current photovoltaic plant
CN106691675A (en) * 2015-07-24 2017-05-24 广州保瑞医疗技术有限公司 Intravascular laser heating whole body thermal therapy instrument
EP3527260B1 (en) * 2016-10-17 2024-04-10 Focuslight Technologies Inc. Semiconductor laser module for application in noninvasive medical treatment
WO2024187107A1 (en) * 2023-03-09 2024-09-12 Sartorius Bioanalytical Instruments, Inc. Instruments and methods for performing optical assays

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