CA1291220C - Multiple antennae breast screening system - Google Patents
Multiple antennae breast screening systemInfo
- Publication number
- CA1291220C CA1291220C CA 522459 CA522459A CA1291220C CA 1291220 C CA1291220 C CA 1291220C CA 522459 CA522459 CA 522459 CA 522459 A CA522459 A CA 522459A CA 1291220 C CA1291220 C CA 1291220C
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- Canada
- Prior art keywords
- breast
- microwave
- antennae
- set forth
- housing
- 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.)
- Expired - Fee Related
Links
Abstract
Abstract of the Disclosure A method and apparatus for cancerous tumor detection employing a plurality of microwave antennae supported in an array conforming substantially in size to the breast that is being screened. In one embodiment of the invention a single array is used and another embodiment for larger breasts a pair of arrays are used. A microwave radiometer is used for detecting temperature readings corresponding respectively to the breast temperature at sites underlying the receiving antennae. Also, in accordance with the invention compression is employed so as to reduce tissue thickness enabling far more rapid reading of antenna sites.
Description
2~
Background of the Invention _ . _ The present invention relates in general to an apparatus and associated method for the detection of cancerous tumors. More particularly, the inven-tion relates to a system for the screening of cancer-ous tumors particularly female breast tumors. Even more particularly, the present invention relates to a microwave system for breast screening for locating tumors.
There is a continuing need for providing a reliable, noninvasive and nonhazardous technique for the detection o~ cancerous tumors especially breast tumors. One such -technique ls an infrared thermo-graphic technique for cancer tumor detection, based on elevated temperatures often found in malignant tumors. This technique is noninvasive and nonhazard-ous but i~ of questionable accuracy. A more accurate technique is mammography. One objection to the well known ~29~L220 mammography technique is that it exposes the person to hazardous x-rays. With regard to infrared thermography, one of its drawbacks is its poor penetration through biological tissues, resulting in the measurement of only surface temperature.
Reference is also maae to my ~.S. patent 4,346,716 covering a microwave detection system for detection of cancerous tumors. This system employs a single detection antenna. If this system i5 employed for breast screening the examination time is far too long and is thus unacceptable. Furthermore, even though microwave techniques provide subsurface sensing, , there is some limitation on the limit of depth detection.
In one prior system employing a single antenna this had to be mechanically positioned requiring approximately 1.5 minutes per site and a minimum of 9 positions per breast in order to provide acceptable coverage. This resulted in a time of e!xamination of 30-40 minutes. Again, this is too long a period of time for practical purposes.
A further problem realized with the single antenna system is associated with the depth of the tumor, particularly in large breasts. It was found that there was a resultant high number of particularly false negative readings.
Accordingly, it is an ob~ect of the present lnYention to provide an improved method and apparatus for the detection of ~ ~ ~ \
g~2~
cancerous tumors, particularly breast tumors.
Another ob~ect of the present invention is to provide an improved breast screening technique employing microwave detection principles.
A further ob]ect of the present invention is to provide an improved microwave breast screening system employing multiple antennae which is instrumental in dramatically reducing the examination time.
Still another object of the present invention is to provide an improved microwave breast screening system in which all antennae are stabilized at the same time eliminating thermal drift due to both patient and environmental changes.
A further object of the present invention is to provide a microwave breast screening sys~em used in combination with breast compression so as to permit examination from opposite surfaces of the compressed breast tissue.
StilI a further object of the present invention is to provide a microwave breast screening system having multiple antennae in which any given antenna thereof may be optimi2ed for a given site. For example, the match of the nipple area of the breast is different from the surrounding tissue and thus the antenna element associated therewith can be optimized as to impedance match for that particular site.
~312~0 Su~mary of the Invention To accomplish the foregoing and other objects, features and advantages of the invention, there is provided both an a means for supporting these antennae in an array that conforms substantially in size to the breast being screened. In addition ~o the use of a plurality of antennae, there is also provided in accordance with the invention means for compressing the breast so as to reduce the tissue thickness being examined. Means are provided coupled from trhe receiving antenna array for detecting the temperature readings corresponding, respectively, to the breast ~emperature at the sites underlining the receiving antennae. In accordance with one embodiment of the invention usable in particular for screenlng small breasts, the antennae are supported in a housing having a cupped surface at which the antennae are supported. The antenna array is substantially symmetric so as to provide multiple uniform breast coverage. In this embodiment of the invention as well as in the second embodiment to be described hereinafter each antenna has a domed end at the housing cupped surface so as to prevent air pockets between the housing and breasts. In the embodiment of the invention employing a single set of antennae the compression i6 carried out manually by the person being screened by virtue of providing a gripping bar associated with the apparatus, which : ,. ., , . -, ~ . - -~Zgl~20 gripping bar enables the person to firmly hold the antenna array against the breast. In this embodiment the cupped surface is su~ported substantially vertically.
In accordance with the second embodiment of the present invention, there are provided first and second sets of receiving antennae. In the embodiment disclosed herein there are six upper and six lower antennae. The means for supporting these antennae includes first and second housing~ each having a cupped surface at which the first and second sets of antennae are respectiY~-ly supported. In this arrangement compression of one brea~t is followed by compression of the other breast. In this regard the first and second housings are commonly mounted with the associated cupped surfaces disposed in facing relative relationship ~ith the first housing disposed substantially horizontal and ~n a fixed position and the second housing being supported ~ver-the first housing. In this embodiment the means for compressi~n includes carriage means on ~ support member and means for operating the carriage means to bring the second housing toward the first housing to compre-~s the breast between the housings. There is pre~erably provided a pivotal adiustment and a pivotal posittoning of the second houstng so that the second housing is at an angular tilted position relative to the f irst housing. This pivotal adjustment enables the operator of the apparatus to provide the proper amount of .. .
.,, ' . . .- ' .
~291~2~
compression so that the antenna array is firmly disposed asainst the breast but at the same time does not make the compression uncomfortable to the person.
The breast compression that is used in accordance with the present invention has been found to provide many advantases.
The compression reduces the material thickness and thus makes readings more accurate. With the dual housing arrangement there may then be a determination of depth by Yirtue of this compression because there will be examination from opposite surfaces of the compressed tissue. Furthermore, compression leads to tumor enhancement because of ~he reduced blood circula~ion thus reducing the temperature of the tissue surrounding the tumor with respect to the tumor tissue itself.
The cancerous tissue tends to be hotter and by restricting the blood flow via compression this tends to enhance the temperature differential between the tumor site and the surrounding tissue.
In accordance with the associated method of the invention there are provided either a single or two pluralities of microwave receiving antennae. These are supported in either a single or two arrays with each array conforming substantially in size to the breast that is being screened. In either embodiment described herein, the breast is compressed so as to reduce tissue thickness that $s being examined. Using a single ,. .
ff,~
~ , .
,. ., , , .; . ~
1'~91220 set of antennae the breast is compressed inwardly under operation of the person being tested. In the second embodiment of the invention in which there are two sets of antenna arrays the breast is disposed between the array housings and the housings are brought together to cause compression.
Compression of one breast is followed by compression of the second breast with common points on each breast being compared. In making these comparisons if there is a temperature differential between like sites on either breast then this may be an indication of a heated site area occasioned by the subsurface presence of a tumor.
Brief Description of the Drawings Numerous other objects, features and advantages of the invention shoulo now become apparent upon a reading of the following detaile~ description taken in conjunction with the accompanying drawing, in which:
FIG. 1 is a perspectiVe View illustrating a first embodiment o~ the present invention employing a double antenna housing with the housings in vertical adjacent position;
FIG. 2 is a side elevation view partially in cross-sectlon illustrating this first embodiment of the invention employing a pair of antenna housings and furthermore illustrating the compression of the breast between these housings in substantially horizontal ad~acent positionS
9~ ~ O
FIG. 3 is a further side elevation view partially in cross~section and illustrating ~urther details in connection with the embodiment of FIG. 2;
FIG. 4 is a partial cross-sectional plan view taken along line 4-4 of FIG. 3;
FIG. 5 is a partial cross-sectional plan view taken along line 5-5 of FIG. 3;
FI~. 6 is a partial cross-sectional rear elevation view : taken along line 6-6 of FIG. 5;
FIG. 7 is a partial cross sectional front elevation view taken along line 7-7 of FIG. 4;
FIG. 8 is a cross-sectional view through one of the antennae as taken along line 8-8 of FIG. 7;
FIG. 9 is a plan view of an alternate antenna construction :In accordance with the invention for use with larger breasts;
F~G~ is a cross-sectional view taken along line 10-10 of . .
FIG..9;
FIG. 11 is a further cross-sectional view showing further details as taken along line 11-11 o~ FIG. 1~:
FIG. 12 is a plan view of the apparatus of the invention in the second embodiment of the invention in which the housing is substantially vertical and furthermore illustrating the compression of one breast against the antenna arrays 9~ ~ZO
FIG. 13 is a plan view of the antenna array in the embodiment of FIG. 1~;
FIG. 14 is a cross-sectional view of the antenna array of ~IG. 12 taken along line 14~14 of FIG. 13;
FI~. 15 is a schematic circuit diagram of a microwave radiometer employed in the system of this invention;
FIG. 16 shows the single housing antenna pattern FIGS. 17-19 show one version of the dual housing antenna patterns for different antenna placement positions;
FI~S. 20-22 show another version of the dual housing antenna patterns for different antenna placement po~sitions;
FIG. 23 illustrates a microwave thermogram and associated temperature plot for the single housing antenna pattern; and FIG. 24 is a circuit diagram associated with the control electronics associated with temperature measurement.
,~ , Detailed Description Referring now to the drawings, there are described herein .
basically two different versions of detection apparatus ~or the microwave detection of breast tumors. In one version as noted in FIG. 12~ there is the use of a single antenna housing. This is usable in particular with small breasts. For normal size to large breasts the dual housing arrangement is employed such as illustrated in FIGS. 1-3. In the dual housing arrangement the _g_ ` ~X91~20 breast is compressed between the two housings as noted in dotted outline in FIG. 2. In either case in accordance with the invention there is provided a plurality of microwave receiving antennae. These` antennae are used, as previously mentioned, in association with physical compression of the breast. Tbe co~pression occurs in the second version as noted in FIG. 2. In the first version of the invention the compression occurs by virtue of the person being examined compressing the antenna array inwardly toward the chest against the breast.
The breast compression that is used in accordance with the present invention has been found to provide many advantages.
The compression reduces the material thickness and thus makes readings mor~ accurate. ~ith the dual housing arrangement there may then -be a determination of depth by ~irtue of this compression ~-écause there will be examination from opposite surfaces oî the compressed tissue. Furthermore, compression :leads to tumor enhancement because of the reduced blood circulation thus reducing the temperature of the tissue surrounding the tumor with respect to the tumor tissue itself.
The cancerous tissue tends to be hotter and by restricting the blood flow via compression this tends to enhance the temperature differential between the tumor site and the surrounding tissue.
., " ' ~ , ' ~91~0 The use of multiple antennae provides improved performance. The individual antennae can be site-optimized.
Also, data acquisition is possible thus dramatically reducing drift in both equipment and the patient. As indicated compression reduces tissue thickness and allows measurement from opposite surfaces of the breast. This enhances the ability to locate deep lesions. The results that are obtained can be carried out so that they can be readily compared to measurements takèn by way of mammography techniques.
As indicated before, the multiple antenna approach results in improved performance due to site-optimized antennae. The multiple antennae reduce the examination time because all antennae are thermally matched simultaneously, allowing rapid data acquisition. Rapid data acquisition in turn eliminates or dramatically reduces dri~t due-to environmental, eguipment or patient conditions.
As mentioned previously, one of the advanta~es of the present invention is the reduction in examination time.
However, it is further noted that with the use of both compression to reduce the tissue thickness and the ability to look from two opposing surfaces, this enables one to look deep into particularly large breasts. In addition, the use of multiple antennae allow site optimization of the antenna element~, such as might be necessary in the area of the nipple.
, . ,. . - ~
~l29 1 220 Now~ with regard to the drawings and in particular to FIG.
1, there is ill~strated the apparatus of the present invention which comprises a slide assembly 10 that may be secured to a wall in a room. This slide assembly 10 supports a beam 12 which is adapted to be maintained in a horizontal position as illustrated in FIG. 1. However, the beam 12 is pivotal about the axis 14. The beam 12 is carried in a vertically movable carriage 16 supported from cables 18 that extend from the counter balance assembly 20. The assembly 20 is at the top of the slide assembly 10. There is also provided a lock 22 that locks the carriaye 16 in a desired vertical position. There is also provided a rotational lock 24 that locks the beam 12 in a certain horizontal rotational position. The operator of the apparatus can easily release the locks 22 and 24 to move the c~rriage 16 up and down and also to move the beam 12 in a horizontal plane. The beam 12 at its outer end supports the ver~ical post 26. The post 26 may be firmly secured a~ the end o~ the beam 12 and supports at its lower end bracket 28.
Bracket 28 is an L-shaped bracket that is clearly illustrated in FIGS. 2 and 3. The interconnection between the bracket 28 and the post 26 permits pivotal ~rictional rotation between the bracket 28 and the post 26. This likewise permits rotational movement in a horizontal plane of the antenna housing 30.
The bracket 28 includes a leg 29 that is secured to the ~ . .. .
9 ~2 Z 0 rotational pivot 320 The rotational pivot ~2 is also secured to the main support member 34 of the apparatus. The rotational pivot 32 permits the sup~ort member 34 to rotate essentially in a vertical plane. In this regard, FIG. 1 shows the support member 34 in a horizontal position while FIG. 2 shows the support member 34 in a vertical position.
In FIGS~ 1 and 2, double antenna housings are employed, but illustrated in different respective positions. In the instance illustrated in FIG. 1 the antenna housings 38, 48, (housinq 48 being disposed behind housing 38) are both disposed in a vertical position corresponding to the le~t side lateral position illustrated in FIG. 19.
Hereinafter, in connection with FIGS. 12-14, there is an illustration of a si~gle housing that is used. A single housing version of ~he invention is usable in particular with breasts of a size on ~he order of 4" or less.
For larger brea~s that are defined herein as being in sizes of 5 1~2n, 7" or 9" the apparatus such as illustrated in FIGS. 1-3 are employed in which there are a pair of antenna housings. As far as the portion of the apparatus that supports the housings is concerned, the same basic construction is used in connection with the description of FIGS. 1-3. Accordingly, like reference ~haracters are of course used to identify like parts including the support member 34 illustrated herein~ The ; i, . ,, , ,~ , ,, ,, ~
9~.~Z~
antenna housing 38 is the lower most housing and includes a cupped surface 39 at which the antennae 40 are supported in an array 41. The housing 38 is supported at the very bottom end of the support member 34. There is provided a lower housing clamp 42 that locks the housing 38 in position. Above the clamp 42 is a further lock 44 that is used to lock the position of the rotational pivot 32.
~ ith resàrd to the rotational pivot 32 it is noted that it is basically maintained in one of two different positions which are displaced 90 to each other. Again, in FIG. 1 it is shown in one position and in FIG. 2 it has been rotated 90 50 that the support me~ber 34 is in an upright position thus enabling the housings to be disposed on the support member in overlying relationship as illustrated in FIGS. 2 and 3~
The second antenna housing 48 is disposed in overlying relationship to the ~lousing 36 -and-also has a cupped surface 49 at which the ante~n~ 50 are ~upported. The antennae 50 are supported in an array 51.
The antenna housing 48 is also ,supported from the support member 34 but rather than being supported in a fixed position as is the housing 38, the housins 48 is supported both in the manner to Fivot and also in a manner to move vertically relative to the housing 38. The housing 48 is supported from a U-shaped bracket S2 illustrated in a plan view in FIG. 5. The ` ` 1291~20 housing 48 is locked to the bracket 52 by means of the clamp 54. The housing 48 enyages with the U-shaped bracket 52 and the sliding relationship therewith such as illustrated in FIG.
5.
As illustrated in FIG. 2, the support member 34 has side pieces 56 and 57. The side piece 57 carries the scale 58. The scale 58 as illustrated in FIGS. ~, 3 and 5. The side piece 56 supports the rack 60.
In FIGS. 2, 3 and 5 there are shown two control knobs as~ociated with operation of the housing 48. One is the knob 62 and the other is the knob 64. The knob 62 is used to control the distance between the housings. This knob is attached to a shaft 63 that carries the pinion gear 65 that is adapted to enga~e with the rack 60. In this regard also note the cro~s-sectional view of FIG. 6 which shows the knob 62 connected to the pinion gear 65 which in turn is engaged with the rack 60.
The knob 64 clamps the rotational position of the antenna housing 48. This pivoting of the housing 48 is at the pivot 70. gnob 64 clamps the lock bars 68 against the frame to hold the antenna arrays in the proper angular position. As illustrated in PIGS. 3 and 5 there are also a pair of lock bar 6a associated with the pivot 66. In FIG. 5 the pivot for the housing 48 rotation is at 70.
~L29~220 Thus, the rack and pinion are engaged in order to move the housing 48 up and down and the knob 64 is used to clamp the housing 48 in a predetermined rotational position with the housing 48 rotating about a pivot axis as indicated,at 70 in FIG. 5. FIG. 5 also shows the Teflon slides 71 disposed on either side of the rack 60 and also on the other side of the side piece 56. FIG. 5 furthermore illustrates the dial 73 which indicates rotation of the housing 48. In this regard also note the dial 73 in FIG. 3 indicating a degree of rotation of approxi,mately 15. The scale 58 is also illustrated in ~IG.
Background of the Invention _ . _ The present invention relates in general to an apparatus and associated method for the detection of cancerous tumors. More particularly, the inven-tion relates to a system for the screening of cancer-ous tumors particularly female breast tumors. Even more particularly, the present invention relates to a microwave system for breast screening for locating tumors.
There is a continuing need for providing a reliable, noninvasive and nonhazardous technique for the detection o~ cancerous tumors especially breast tumors. One such -technique ls an infrared thermo-graphic technique for cancer tumor detection, based on elevated temperatures often found in malignant tumors. This technique is noninvasive and nonhazard-ous but i~ of questionable accuracy. A more accurate technique is mammography. One objection to the well known ~29~L220 mammography technique is that it exposes the person to hazardous x-rays. With regard to infrared thermography, one of its drawbacks is its poor penetration through biological tissues, resulting in the measurement of only surface temperature.
Reference is also maae to my ~.S. patent 4,346,716 covering a microwave detection system for detection of cancerous tumors. This system employs a single detection antenna. If this system i5 employed for breast screening the examination time is far too long and is thus unacceptable. Furthermore, even though microwave techniques provide subsurface sensing, , there is some limitation on the limit of depth detection.
In one prior system employing a single antenna this had to be mechanically positioned requiring approximately 1.5 minutes per site and a minimum of 9 positions per breast in order to provide acceptable coverage. This resulted in a time of e!xamination of 30-40 minutes. Again, this is too long a period of time for practical purposes.
A further problem realized with the single antenna system is associated with the depth of the tumor, particularly in large breasts. It was found that there was a resultant high number of particularly false negative readings.
Accordingly, it is an ob~ect of the present lnYention to provide an improved method and apparatus for the detection of ~ ~ ~ \
g~2~
cancerous tumors, particularly breast tumors.
Another ob~ect of the present invention is to provide an improved breast screening technique employing microwave detection principles.
A further ob]ect of the present invention is to provide an improved microwave breast screening system employing multiple antennae which is instrumental in dramatically reducing the examination time.
Still another object of the present invention is to provide an improved microwave breast screening system in which all antennae are stabilized at the same time eliminating thermal drift due to both patient and environmental changes.
A further object of the present invention is to provide a microwave breast screening sys~em used in combination with breast compression so as to permit examination from opposite surfaces of the compressed breast tissue.
StilI a further object of the present invention is to provide a microwave breast screening system having multiple antennae in which any given antenna thereof may be optimi2ed for a given site. For example, the match of the nipple area of the breast is different from the surrounding tissue and thus the antenna element associated therewith can be optimized as to impedance match for that particular site.
~312~0 Su~mary of the Invention To accomplish the foregoing and other objects, features and advantages of the invention, there is provided both an a means for supporting these antennae in an array that conforms substantially in size to the breast being screened. In addition ~o the use of a plurality of antennae, there is also provided in accordance with the invention means for compressing the breast so as to reduce the tissue thickness being examined. Means are provided coupled from trhe receiving antenna array for detecting the temperature readings corresponding, respectively, to the breast ~emperature at the sites underlining the receiving antennae. In accordance with one embodiment of the invention usable in particular for screenlng small breasts, the antennae are supported in a housing having a cupped surface at which the antennae are supported. The antenna array is substantially symmetric so as to provide multiple uniform breast coverage. In this embodiment of the invention as well as in the second embodiment to be described hereinafter each antenna has a domed end at the housing cupped surface so as to prevent air pockets between the housing and breasts. In the embodiment of the invention employing a single set of antennae the compression i6 carried out manually by the person being screened by virtue of providing a gripping bar associated with the apparatus, which : ,. ., , . -, ~ . - -~Zgl~20 gripping bar enables the person to firmly hold the antenna array against the breast. In this embodiment the cupped surface is su~ported substantially vertically.
In accordance with the second embodiment of the present invention, there are provided first and second sets of receiving antennae. In the embodiment disclosed herein there are six upper and six lower antennae. The means for supporting these antennae includes first and second housing~ each having a cupped surface at which the first and second sets of antennae are respectiY~-ly supported. In this arrangement compression of one brea~t is followed by compression of the other breast. In this regard the first and second housings are commonly mounted with the associated cupped surfaces disposed in facing relative relationship ~ith the first housing disposed substantially horizontal and ~n a fixed position and the second housing being supported ~ver-the first housing. In this embodiment the means for compressi~n includes carriage means on ~ support member and means for operating the carriage means to bring the second housing toward the first housing to compre-~s the breast between the housings. There is pre~erably provided a pivotal adiustment and a pivotal posittoning of the second houstng so that the second housing is at an angular tilted position relative to the f irst housing. This pivotal adjustment enables the operator of the apparatus to provide the proper amount of .. .
.,, ' . . .- ' .
~291~2~
compression so that the antenna array is firmly disposed asainst the breast but at the same time does not make the compression uncomfortable to the person.
The breast compression that is used in accordance with the present invention has been found to provide many advantases.
The compression reduces the material thickness and thus makes readings more accurate. With the dual housing arrangement there may then be a determination of depth by Yirtue of this compression because there will be examination from opposite surfaces of the compressed tissue. Furthermore, compression leads to tumor enhancement because of ~he reduced blood circula~ion thus reducing the temperature of the tissue surrounding the tumor with respect to the tumor tissue itself.
The cancerous tissue tends to be hotter and by restricting the blood flow via compression this tends to enhance the temperature differential between the tumor site and the surrounding tissue.
In accordance with the associated method of the invention there are provided either a single or two pluralities of microwave receiving antennae. These are supported in either a single or two arrays with each array conforming substantially in size to the breast that is being screened. In either embodiment described herein, the breast is compressed so as to reduce tissue thickness that $s being examined. Using a single ,. .
ff,~
~ , .
,. ., , , .; . ~
1'~91220 set of antennae the breast is compressed inwardly under operation of the person being tested. In the second embodiment of the invention in which there are two sets of antenna arrays the breast is disposed between the array housings and the housings are brought together to cause compression.
Compression of one breast is followed by compression of the second breast with common points on each breast being compared. In making these comparisons if there is a temperature differential between like sites on either breast then this may be an indication of a heated site area occasioned by the subsurface presence of a tumor.
Brief Description of the Drawings Numerous other objects, features and advantages of the invention shoulo now become apparent upon a reading of the following detaile~ description taken in conjunction with the accompanying drawing, in which:
FIG. 1 is a perspectiVe View illustrating a first embodiment o~ the present invention employing a double antenna housing with the housings in vertical adjacent position;
FIG. 2 is a side elevation view partially in cross-sectlon illustrating this first embodiment of the invention employing a pair of antenna housings and furthermore illustrating the compression of the breast between these housings in substantially horizontal ad~acent positionS
9~ ~ O
FIG. 3 is a further side elevation view partially in cross~section and illustrating ~urther details in connection with the embodiment of FIG. 2;
FIG. 4 is a partial cross-sectional plan view taken along line 4-4 of FIG. 3;
FIG. 5 is a partial cross-sectional plan view taken along line 5-5 of FIG. 3;
FI~. 6 is a partial cross-sectional rear elevation view : taken along line 6-6 of FIG. 5;
FIG. 7 is a partial cross sectional front elevation view taken along line 7-7 of FIG. 4;
FIG. 8 is a cross-sectional view through one of the antennae as taken along line 8-8 of FIG. 7;
FIG. 9 is a plan view of an alternate antenna construction :In accordance with the invention for use with larger breasts;
F~G~ is a cross-sectional view taken along line 10-10 of . .
FIG..9;
FIG. 11 is a further cross-sectional view showing further details as taken along line 11-11 o~ FIG. 1~:
FIG. 12 is a plan view of the apparatus of the invention in the second embodiment of the invention in which the housing is substantially vertical and furthermore illustrating the compression of one breast against the antenna arrays 9~ ~ZO
FIG. 13 is a plan view of the antenna array in the embodiment of FIG. 1~;
FIG. 14 is a cross-sectional view of the antenna array of ~IG. 12 taken along line 14~14 of FIG. 13;
FI~. 15 is a schematic circuit diagram of a microwave radiometer employed in the system of this invention;
FIG. 16 shows the single housing antenna pattern FIGS. 17-19 show one version of the dual housing antenna patterns for different antenna placement positions;
FI~S. 20-22 show another version of the dual housing antenna patterns for different antenna placement po~sitions;
FIG. 23 illustrates a microwave thermogram and associated temperature plot for the single housing antenna pattern; and FIG. 24 is a circuit diagram associated with the control electronics associated with temperature measurement.
,~ , Detailed Description Referring now to the drawings, there are described herein .
basically two different versions of detection apparatus ~or the microwave detection of breast tumors. In one version as noted in FIG. 12~ there is the use of a single antenna housing. This is usable in particular with small breasts. For normal size to large breasts the dual housing arrangement is employed such as illustrated in FIGS. 1-3. In the dual housing arrangement the _g_ ` ~X91~20 breast is compressed between the two housings as noted in dotted outline in FIG. 2. In either case in accordance with the invention there is provided a plurality of microwave receiving antennae. These` antennae are used, as previously mentioned, in association with physical compression of the breast. Tbe co~pression occurs in the second version as noted in FIG. 2. In the first version of the invention the compression occurs by virtue of the person being examined compressing the antenna array inwardly toward the chest against the breast.
The breast compression that is used in accordance with the present invention has been found to provide many advantages.
The compression reduces the material thickness and thus makes readings mor~ accurate. ~ith the dual housing arrangement there may then -be a determination of depth by ~irtue of this compression ~-écause there will be examination from opposite surfaces oî the compressed tissue. Furthermore, compression :leads to tumor enhancement because of the reduced blood circulation thus reducing the temperature of the tissue surrounding the tumor with respect to the tumor tissue itself.
The cancerous tissue tends to be hotter and by restricting the blood flow via compression this tends to enhance the temperature differential between the tumor site and the surrounding tissue.
., " ' ~ , ' ~91~0 The use of multiple antennae provides improved performance. The individual antennae can be site-optimized.
Also, data acquisition is possible thus dramatically reducing drift in both equipment and the patient. As indicated compression reduces tissue thickness and allows measurement from opposite surfaces of the breast. This enhances the ability to locate deep lesions. The results that are obtained can be carried out so that they can be readily compared to measurements takèn by way of mammography techniques.
As indicated before, the multiple antenna approach results in improved performance due to site-optimized antennae. The multiple antennae reduce the examination time because all antennae are thermally matched simultaneously, allowing rapid data acquisition. Rapid data acquisition in turn eliminates or dramatically reduces dri~t due-to environmental, eguipment or patient conditions.
As mentioned previously, one of the advanta~es of the present invention is the reduction in examination time.
However, it is further noted that with the use of both compression to reduce the tissue thickness and the ability to look from two opposing surfaces, this enables one to look deep into particularly large breasts. In addition, the use of multiple antennae allow site optimization of the antenna element~, such as might be necessary in the area of the nipple.
, . ,. . - ~
~l29 1 220 Now~ with regard to the drawings and in particular to FIG.
1, there is ill~strated the apparatus of the present invention which comprises a slide assembly 10 that may be secured to a wall in a room. This slide assembly 10 supports a beam 12 which is adapted to be maintained in a horizontal position as illustrated in FIG. 1. However, the beam 12 is pivotal about the axis 14. The beam 12 is carried in a vertically movable carriage 16 supported from cables 18 that extend from the counter balance assembly 20. The assembly 20 is at the top of the slide assembly 10. There is also provided a lock 22 that locks the carriaye 16 in a desired vertical position. There is also provided a rotational lock 24 that locks the beam 12 in a certain horizontal rotational position. The operator of the apparatus can easily release the locks 22 and 24 to move the c~rriage 16 up and down and also to move the beam 12 in a horizontal plane. The beam 12 at its outer end supports the ver~ical post 26. The post 26 may be firmly secured a~ the end o~ the beam 12 and supports at its lower end bracket 28.
Bracket 28 is an L-shaped bracket that is clearly illustrated in FIGS. 2 and 3. The interconnection between the bracket 28 and the post 26 permits pivotal ~rictional rotation between the bracket 28 and the post 26. This likewise permits rotational movement in a horizontal plane of the antenna housing 30.
The bracket 28 includes a leg 29 that is secured to the ~ . .. .
9 ~2 Z 0 rotational pivot 320 The rotational pivot ~2 is also secured to the main support member 34 of the apparatus. The rotational pivot 32 permits the sup~ort member 34 to rotate essentially in a vertical plane. In this regard, FIG. 1 shows the support member 34 in a horizontal position while FIG. 2 shows the support member 34 in a vertical position.
In FIGS~ 1 and 2, double antenna housings are employed, but illustrated in different respective positions. In the instance illustrated in FIG. 1 the antenna housings 38, 48, (housinq 48 being disposed behind housing 38) are both disposed in a vertical position corresponding to the le~t side lateral position illustrated in FIG. 19.
Hereinafter, in connection with FIGS. 12-14, there is an illustration of a si~gle housing that is used. A single housing version of ~he invention is usable in particular with breasts of a size on ~he order of 4" or less.
For larger brea~s that are defined herein as being in sizes of 5 1~2n, 7" or 9" the apparatus such as illustrated in FIGS. 1-3 are employed in which there are a pair of antenna housings. As far as the portion of the apparatus that supports the housings is concerned, the same basic construction is used in connection with the description of FIGS. 1-3. Accordingly, like reference ~haracters are of course used to identify like parts including the support member 34 illustrated herein~ The ; i, . ,, , ,~ , ,, ,, ~
9~.~Z~
antenna housing 38 is the lower most housing and includes a cupped surface 39 at which the antennae 40 are supported in an array 41. The housing 38 is supported at the very bottom end of the support member 34. There is provided a lower housing clamp 42 that locks the housing 38 in position. Above the clamp 42 is a further lock 44 that is used to lock the position of the rotational pivot 32.
~ ith resàrd to the rotational pivot 32 it is noted that it is basically maintained in one of two different positions which are displaced 90 to each other. Again, in FIG. 1 it is shown in one position and in FIG. 2 it has been rotated 90 50 that the support me~ber 34 is in an upright position thus enabling the housings to be disposed on the support member in overlying relationship as illustrated in FIGS. 2 and 3~
The second antenna housing 48 is disposed in overlying relationship to the ~lousing 36 -and-also has a cupped surface 49 at which the ante~n~ 50 are ~upported. The antennae 50 are supported in an array 51.
The antenna housing 48 is also ,supported from the support member 34 but rather than being supported in a fixed position as is the housing 38, the housins 48 is supported both in the manner to Fivot and also in a manner to move vertically relative to the housing 38. The housing 48 is supported from a U-shaped bracket S2 illustrated in a plan view in FIG. 5. The ` ` 1291~20 housing 48 is locked to the bracket 52 by means of the clamp 54. The housing 48 enyages with the U-shaped bracket 52 and the sliding relationship therewith such as illustrated in FIG.
5.
As illustrated in FIG. 2, the support member 34 has side pieces 56 and 57. The side piece 57 carries the scale 58. The scale 58 as illustrated in FIGS. ~, 3 and 5. The side piece 56 supports the rack 60.
In FIGS. 2, 3 and 5 there are shown two control knobs as~ociated with operation of the housing 48. One is the knob 62 and the other is the knob 64. The knob 62 is used to control the distance between the housings. This knob is attached to a shaft 63 that carries the pinion gear 65 that is adapted to enga~e with the rack 60. In this regard also note the cro~s-sectional view of FIG. 6 which shows the knob 62 connected to the pinion gear 65 which in turn is engaged with the rack 60.
The knob 64 clamps the rotational position of the antenna housing 48. This pivoting of the housing 48 is at the pivot 70. gnob 64 clamps the lock bars 68 against the frame to hold the antenna arrays in the proper angular position. As illustrated in PIGS. 3 and 5 there are also a pair of lock bar 6a associated with the pivot 66. In FIG. 5 the pivot for the housing 48 rotation is at 70.
~L29~220 Thus, the rack and pinion are engaged in order to move the housing 48 up and down and the knob 64 is used to clamp the housing 48 in a predetermined rotational position with the housing 48 rotating about a pivot axis as indicated,at 70 in FIG. 5. FIG. 5 also shows the Teflon slides 71 disposed on either side of the rack 60 and also on the other side of the side piece 56. FIG. 5 furthermore illustrates the dial 73 which indicates rotation of the housing 48. In this regard also note the dial 73 in FIG. 3 indicating a degree of rotation of approxi,mately 15. The scale 58 is also illustrated in ~IG.
3 and gives an indication of,the displacement between the two hou'sings. With regard to the dial 73 this is fixed to the U-shaped bracket 52 and thus rotates with the housing so as to indicate angular displacement of the housing 48.
FIG. 3 illustrates in dotted outline the antenna array 41 associate~ith housing 38 and also shows in cross-section the antenna array 51 associated with the housing 48. There are leads 76 c~pling from each of the antennae 40 of array 41.
These leads couple to a connector 77 and then there are output leads that couple from the housing 38. Similarly, there are leads 78 coupling from the antenna array 51 to a connector 79.
From the connector there are leads that couple out of the movable antenna housing 48.
FIG. 4 is a plan view taken along line 4-4 of FIG. 3. Thi~
.; . ~ ., ~ .
:
. ~29~20 illustrates the particular placement of the antennae 40 in a triangular shaped array all disposed within the cupped surface 39. FIG~ 4 also illustrates the coupling 77 and ehe coupling of leads out of the housing 38. FIG. 4 also illustrates the clamp 42 for clamping the housing 38 in position. In the particular embodiment illustrated as FIG. 4 the antenna array is for use with an intermediate size breast such as the aforementioned 5 1/2" breast. The particular array has a lower most row of three antennae spaced apart, a second row of two antennae staggered in relationship to the first row and a third single antenna altogether making the triangular shape as aforementioned.
Reference is now made to ~IG. 6 which is a rear elevation vi~.w partially in cross-section showing further details of the appa~atus illustrating the movable and rotational upper housing ~le.~nd the fixed lower housing 38. There is illustrated the r~at-ional clamp knob 64 and the knob 62 for setting the dijtance apart ~etween the housingsO FIG. 6 also illustrates the ~lamping or loc~ bars 68, spacers 80t and fiber washers 81. Pins 82 are disposed in association with the non-rotating washer 83.
.Reference is now made to F~G. 7 that illustrates a cross-sectional view with the two housings in confronting relationship and which the cupped surfaces 39 and 49 are in ., .
; , ; . ~,~ ;
~9~o facing relative relationship to each other. Therebetween there i~ shown a dotted outline a warming blanket 84 which is preferably used to warm the cupped surfaces prior to usage as will be described hereinafter. It is furthermore noted that each of the antennae 40 and each of the antennae 50 has a domed end 40A, 50A.
Reference is now made to FIG. 8 which is a cross-sectional view taken along line 8-8 of FIG. 7 showing further details of the afi~enna 40. This antenna is comprised of a section of waveguide 85 and a probe 86 coupling to the coaxial line 87.
The waveguide ~5 is preferably dielectrically filled as shown at 88 in FIG. ~. Also in FIG. 8 it is noted that there is clearly described the domed end 40A of the antenna.
The embodi~ent of the invention illustrated in FIGS. 7 and 8 is used in connection with breast sizes of 5 1/2" and 7n~
~or ~-larger breast of 9" size then it is preferred to use the a~tenna form illustrated in FIGS. 9~11. It is noted that the breast diameter may be determined from previously available mammo~graphy data. FIG. 9 shows the series of antennae 90 disposed in an array 91 covering an area that matches the size of a relatively larse breast identified as a 9" breast herein.
As noted in FIG. 99 these antennae are disposed in the same general pattern as previously illustrated in FIG. 4 in a first row of three antennae, a second row of two antennae and then -lB-.
.
~.~9~
followed by a single antenna disposed in a staqgered arrangement in a generally triangular array.
FIG. 10 is a cross-sectional view similar to that illustrated in FIG. 7 but for the large breast embodiment of the housing. Again, there is described in FI~. 10 the warming blanket 84 and dotted outline used to warm the ends of the antennae. The antennae 90 have domed ends 90A and the overlying antennae 92 have domed ends 92A. Again, these domed ends are for the purpose of preventing air pockets between the breast and the antennae. FIG. 10 also illustrates the cup surface 39 associated with housing 38 and the similar cup surface 49 associated with housing 48.
FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10 showing some further detail of the microwave antenna illustrating in particular the cupped surface 39, domed end 90A
and dielectric filling 94.
Thus, in this embodiment of the invention just described, there are two housings as in the em~odiment illustrated in FIG.
8 each i~cluding 6 antennae of generally rectangu1ar construction each comprising a section of waveguide and a probe for detecting signals from the waveguide. There i~ an array of antennae 91 associated with housing 38 and also an array 93 of antennae associated with the housing 4B. Each of these arrays as noted comprises six antennae each with domed surfaces.
'' . ' 1.29~L~20 ~ eference has been made hereinbefore to the embodiment of the invention in which two housings are used such as in the different positions of FIG. 1 and 2. Mention has also been made of a single antenna housing 30 having associated therewith, handle 35 as referred to in FIG. 12. PIG. 12 also shows the outline of a breast 96. FIG. 12 also shows portions of the apparatus described in FIG. 1 including the vertical post 26, support member 34, and knobs 62 and 64. FIG. 12 also shows in dotted outline an array 100 of antennae 98.
~ eerence is also made to ~IGS. 13 and 14. FIG. 13 shows the housing 30 with the antenna array 100 comprised of six antennae 98. Each of the antennae 98 may be of the construction previously described such as shown in the detail of.F~..B. The waveguide section thereof is preferably dielectrlcally filled and the waveguide sec~ion has a domed end 102. ~ array of six antennae are disposed in the circularly cuppea-s-~rface 104.
FIG..12 shows the placement of the breast compressed against the antenna array 100 this compression is brought ab~ut in this embodiment by virtue of the person being tested grasping the handle 35 and drawing the housing 30 against the breast to flatten the,breast and compress it so as to cover the entire antenna array. As indicated previously this form of the invention is employed in particular with small breasts tha~ may -~0-: - . . .,.. ~, , :
~.291~20 be too small to effectively compress between a pair of housings. Thus, instead a single housing is used with the associated handle 35 for providing compression directly against the breast.
Now, reference ~s made to FI~. 15 which shows a schematic circuit diagram of a microwave radiometer that may be employed in the system of this invention for taking temperature mea~urements. Preferably, a single radiometer is employed and readings are taken in succession from each of the antennae as will be described hereinafter.
With regard to FIG. 15, there is illustrated an input to the switch SWl from the receiver antenna such as from the antennae 40 or 50 as illustrated in FIGS. 2 and 3. The , . . .
microwave radiometer that is depicted may be of the DICKE
switch type. The radiometer desiqn substantially reduces the . . _ effects of short term gain fluctuations in the radiometer. The .
receiver input is switched by means of a switch SWl at a constant rate between the antenna and a constant temperature reference load. The switched, or modulated RF signal is therefore inserted at a point prior to RF amplification and as close to the antenna as possible; in turn, it is then amplified and coherently detected. The final output is proportional to the temperature difference between the antenna and the reference load.
... " , , - . . ..
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~;~9~ O
In FIG. 15 a second switch SW2~ referred to as a calibration switch, may also be employed. With this switch, the reference load as defined by the noise diode 36A and fixed attenuator 38Ao is compared with a base load 4QA rather than with the signal from the an~enna. If the base load is equal in temperature with the reference load, the DC output of the ra2iometer is thus nulled to zero~
The radiometer described herein employs at least one low noise RF amplifier in conjunction with a simple single ended square law detector rather than the more complex superheterodyne which employs a local oscillator and IF
amplifier. The square law detector of this arrangement minimizes the potential drift and noise associated with the superheterodyne approach. The conformance that comprises the radiometer are di~cussed in detail hereinafter.
With r2s~rd t~^the microwave radiometer schematic of FIG.
15, at its i~ t the-e ~s shown the connection which is pre~erably by way of a coax cable from the receiver antenna lapplicator aperture) to one input of switch S~ hls may be termed a calibration switch which is a solenoid-operated , mechan~cal single pole/-double-throw switch used to disconnect the antenna and in its place connect the base load 4QA by way of a second switch S~2. The switch SWl has an isolat~on or switching radio, of greater than 60 dB with a corresponding ' - . ~
1~9~2~) insertion loss of less than 0.1 dB. The switch SW2 is used in the calibration circuit to disconnect the base load and to insert in its place the calibrated noise source as represented by the ~ixed attenuator 38A and the noise diode 36A referred to hereinafter.
As indicated in FIG. 15, there are three ferrite isolators used in the receiver path. These are identified as isolators ISOL-l, ISOL-2 and ISOL-3. The first isolator, is located between the calibration switch S~l an~ the DICXE switch Sh'3.
Thi~ isolator is used to terminate the output of the reference load when the DICKE switch is in the low loss state. In this state, the reference or base load is circulated in the direction of the antenna which, in this case, functions as a ferriie isolator. ~he isolator ISOL-l employs a c:oaxial~to-waveguide transition. The insertion loss of this isol3~0r and the transition is less than 0.~ dB, with a corr~ nding isolation of greater than 2.3 dB.
The second isolator ISOL-2 in FIG. 15, is disposed between the switch SW3 and the first stage RF amplifier to maintain a constant load match to this amplifier. Any reflections from the RF amplifier would therefore be terminated in the isolator. Again, this isolator, which is a waveguide isolator with a coax-to-waveguide transition, has an insertion loss o~
less than 0.2 dB with an isolation o~ greater than 23 dB.
-~3 . . ., . ~. , , ~
.: ' "
1~9~L220 There is also provided in FIG. 15 a third isolator ISOL-3 which is located between the output of the first RP amplifier and the bandpass filter 44A. ~he purpose of this particular isolator is to present a constant load match to the output stage of the first RF amplifier, and also to present a matched input to the bandpass filter 44A.
A switchable ferrite circulator, designated switch SW3 in FI~. 15, forms the load comparison, or DICKE switch, function.
A ferrite device is preferred over a semiconductor approach primarily in view of the lower insertion loss, ~ypically les~
than 003 dB, and elimination of noise generated by the semiconductor junction over and above the measured insertion loss.
Br~efly, the device S~3 is a switchable ferrite junction circulator utilizing the remnant, or latching, characteristics of ~h-e Eerrite material. The principle of latchinq action îs 2~--fo-llows: Using the intrinsic properties of a hysteresis loop of a ferrite toroid, a transverse magnetic field is used across a portion of the ferrite exposed to an RF signal. The biasing field is actually the residual inductance of the ferrite toroid; therefore, the device needs no holding power and can be reversed tn polarity using merely enough energy to overcome the natural coercive force of the toroid.
For the system of this invention, the latching circulator ~24-has been constructed in wave~uide having a single ferrite element contained within the microwave circuit. The insertiOn loss is less than 0.3 dB, having isolation in excess of 20 dB.
The first-stage RF amplifier may be a four stage FET device constructed in microstrip with integrated biasing circuitry.
The noise figure of the first amplifier (M/A Canada amplifier Model No. ~C-2019) is 2.0 dB with a gain of 35 dB. The secon~
RF amplifier Amplica Model No. 3441CS~ has a noise figure of 2.6 dB, with an associated gain of 33 dB. In both instancest the noise figure includes the input ferrite isolator as depicted in FIG. 15. With the input and output VSWR at less than 1.5:1, the gain compression at signal levels of between -5~ dbm to -10 dbm is less than 0.1 dB.
~ n ~IG. 15 the filter 44A is a bandpass filter and the bandwtdth of the microwave radiometer is basically determined by tne`~andpass characteristics of this filter. The filter is dispos~d-dfter the first stage of RF ampli~ication to minimize . .
the imp~ct of the insertion loss of the filter on the overall system per-formance. The filter characteristics are chosen to minimize possible interference due to nearby microwave communications or radar band~. The ilter is preerably an 8-section bandpass ~ilter constructed in stripline. The pass band loss is less than 3 dB and the bandwidth is approximately 500 MHz.
,~ 1,- , ~29~2~0 As indicated in FIG. 15, there are basically two loads provided, a base load 40 and a reference load 42A. The load design is coaxial, employing a stainless steel R~ connector to provide thermal isolation between the load and the remainder of the system. The coaxial termination is containe~ within an insulated housing and utilizes an integrated heater and proportional control to maintain constant temperature. The absolute temperature of both the base and the reference loads is monitored and displayed on a digital temperature indicator (not shown).
The calibration circuit comprises a precision, solid state, noise source having an excess noise ratio, ENR of 33 dB. This allows noise to be injected into the receiver front end via the high isolation mechanical calibration switch. The output level of the noise source is reduced through the use of a precision calibrated pad (43.3 dB~. This calibration circuit is shown in FI~. 15 as including a fixed attenuator 38A and the noise diode 36A.
The lock-in amplifier 50A shown in FIG. 15 enables the accurate measurement of signals contaminated by broad band noise, power line pickup, frequency drift or other sources of interference. It accomplishes this by means of an extremely narrow band detector which has the center of its pass band locked to the frequency of the signal to be measured. Because -2fi-: , ~ ,' ' - . . . , `
. ' ' ' . . .'.
, ., ~ ~ 9 ~Z2~
of the frequency lock and narrow bandwid~h, large improvements in ~ignal-to-noise ratio are achieved. This allows the 6ignal of interest to be accurately measured, even in situations where it is completely masked by noise. In addition, the lock-in amplifier 50A provides the synchronous function associated with the DICKE switch i.e., the unit supplies the 100 Hz reference clock frequency to drive the ferrite switch driver.
The system is provided, of course, with a power ~upply comprising two 12-volt 50 amp maintenance freet lead-acid batteries in series, fused at 10 amps per battery. The outputs from the battery assembly include 12 and 24 volts~ These voltages are appropriately applied to the receiver and lock-in amplifier. There may also be provided a voltage converter and regulator;'' Status indicators may be employed for indicating operating voltages. The main operating switch may have three positions i'ncluding an on position, an off position and a "charged" po~ition. In the charged mode, a meter is used to monitor the charge current to the batteries which is limited to approximately 6 amps. With a 3-6 amp-hour discharge rate (a normal 12 hour operating mode), the recharge cycle is approximately 10-12 hours (overnight).
With the' system o~ the present invention thermal drift i~
essentially eliminated. This is the case because all antennae are positioned concurrently and all readings taken ... ~ .. .. . ...
- ' .
. . .
~ ~ 9 ~2 ~
substantially concurrently. Moreover, the antenna surface that the breast contacts is warmed so that the readings can be taken in ~ay 1 minute to say 1.5 minutes rather than waiting a substantially longer time for proper temperature stabilization. It is preferred to warm the cupped surfaces 39 and 49 and of course the associated antenna domed ends to a t~mperature on the order of body temperature. This may be carried out by means o~ a warming pad as has been illustrated in the drawings. The preferred temperature ~hat the cupped surfaces are raised to is in the range of 30C-34C. This gets the surfaces that the breasts are going to come into contact with close to human skin temperature.
As indicated previously, in the embodiment employing a single antenna housing once the antennae are warmed the person being examined can themselves press the antenna array against the breast and readings can be taken in approximately 1 to 1.5 minutes. In the other embodiment of the invention that is more universally used, the lower antenna housing is ~ixed in position and the upper antenna housing moves downwardly and is capa~le of pivoting as clearly indicated in FIGS. 2 and 3 of thls application to cause compression of the breast such as illustrated in dotted outline in ~IG. 2. It has been ~ound that the upper housing generally does not become horizontal but is instead moved to a position approximately as illustrated in -~8~
'~, ' , ' ' , ~1 ~9~20 FIG. 2 tilted at a slight anglè usually in the range of 10 -35. It has been found that it is preferred not to have the housings horizontal as this provides too much compression and discomfort regarding these breasts being examined. It is only necessary that the antenna array make good contact with the tissue and that there be no air gaps between the antenna and the tissue. It is also important that the antenna array be somewhat matched in size to the breast being examined so that all antennae are properly covered. Any air gaps will create a mismatch. Also, in accordance with the invention the domed antenna structure is important in assuring that air gaps or air pockets do not form.
Reference is now made to FIGS. 16-22 in connection with a . .
group of- schematic diagrams that illustrate each of the different types of antenna arrays and the associated patterns for each breast. In this regard, FIG. 16 relates t~ the single antenna--housing version illustrated in FIGS. 1 and 12-14 o~ the inVeD~iOn, FIGS. 17-19 show patterns associated with the dual antenna~housings for 5 1/2" and 7" breasts. Finally, FIGS.
20-22 illustrate patterns in association with a 9" breast. In FIGS. 17-22 the patterns are illustrated cranio-caudad oblique and lateral, respectively.
FIG. 16 illustrates the antenna array 100 at the top for the left side and at the bottom for the right side. This is in ! ' ' .
;' ~ 2 0 connection with a relatively small size breast considered to ~e a 4" breast. Also note in FIG. 1~ the medial markers M. Each of these arrays comprise six antennae identified as ~ 6.
It is noted in the array illustrated in FIG. 16 that four of the antennae, ~l, #2, ~3 and ~6 are grouped more closely together at the outside of the breast while ~4 and ~5 are grouped closer to the medial marker M.
Now, it is noted that in FIG. 16 the outermost antenna is ~1 both with respect to the left breast and the right breast.
This i~ so that the ~1 readings are compared with comparisons being made at common points on each breast. ~or example, the right upper outer antenna ~6 is compared with the left upper outer antenna ~6. Because when the breast is compressed against the antenna array the antennae are actually in different positions depending ~pon whether it is the left breast or the right breast, information is fed into the system so that the proper comparisons are made of a common point on each breast. ~t may be, two separate housings 30 may even be employed one f~r the left breast and one ~or the r~ght breast.
FIGS. 1~-19 illustrate schematically the antenna array placements for the dual arrays, these are the arrays previously referred to as arrays 41 and 51 in FIG. 7. Again, in, for example, FIG. 17 the location ~1 on the left side i8 compared with the location ~1 on the right side. The position of FIG.
7 . . , , . ', . ...
," ;' , ., ~ ~ 9 ~X ~ O
17 relates to the position of housings of FIG. 2~ Again, in connection with FIGS. 17-lg it must be remembered ~hat when one is observing both sides of the breast using six upper antennae and six lower antennae. Thus, the right outer upper antenna is compared with the same position on the left breast or in other words the left outer upper antenna. Because the breasts are inserted in the same direction between the antenna housings this means that the equipment must int~rpret whether a left breast or a right breast is being examined. It then senses the signals from the antennae in the proper manner so that the proper points are compared. For example, in FIG. 17 it is noted that antenna ~6 on the left side appears to be in line with antenna ~1 on the right side. However, the electronics in t:he system interp~ets the readings differently so that the both ~1 sites are compared between left and right sides.
FIG. 17 illustrates the detection and compression as being in the cranio-caudad diEection. FIG. 18 indicates the compression ano sensing being at the oblique direction. In F~G. 19 the sensin~ is done in the lateral position such as illustrated previously in FIG. 1.
FIGS. 20-22 describes similar arrangements in connection with the embodiment of the invention illustrated in FIG. 10.
This is for the larger breast employing arrays 91 and 93. Once again, comparisons are made between the same common points on : . , : , :
each breast. For example~ in FIG~ 20 the left upper outer antenna ~1 is compared with the right outer upper antenna tl.
When the breast is inserted into the position between the housings there may be in fact two different antennae that will be used for detecting these common points but the electronics interprets whether the left or right ~reast is being examined and then takes the appropriate reading from the appropriate antenna so that the common comparisons can take place.
In FIG. 20 the position is cranio-caudad. In FIG. 21 the patt~rn is illustrated as oblique. In FIG. 22 the pattern is lateral.
It,is further to be noted~that the compression that has been referred to previously is also believed to lead to ~umor enhancement. An elevated temperature is generally associated with the tumor due to the metabolic activity of the tumor. The cell~ are consuming energy and thus ge~erate heat. In a cancerous tumor the cells double faster and thus are more active ~nd generate more heat. Also, the tumor has generally poor vascularity and thus cannot dump the heat that good.
Thus, when the blood circulating about the tumor is also compressed this reduces the temperature of the surrounding t~ssue with respect to the tumor tissue. This thus tends to enhance the temperature differential between the tumor itself and the surrounding temperature.
~ ' ~ . . , - r ( ~z ~ 2 0 As indicated previously, it is des~red to compare the like or common locations between each breast to determine a temperature differential therebetween. It is also desired to have the capability of making a comparison ~etween a particular temperature at an antenna loca~ion for comparison with the average breast temperature. There is a possibility of cold spots in the breast and thus it is preferred to average the temperature throughout the breast and then make the comparison of the average with each individual reading.
Reference is now made to FIG. 23 which shows a microwave thermogram. Thls is in association with the embodiment of the invention employing five antennae illustrated at the left breast as antennae ~2t t4, ~6, ~8, ~10 and ~12. Associated with t~e right breast are antennae ~1, t3, #5, ~7, ~9 and ~11.
Also s~own this plot indicating temperature associated with r~ ~
each of the four numbered antennae. Also illustrated in FIG.
i .
23 is ~;,site 110 where a tumor exists. ~ith reference to the drawing it- it noted that, for example, a comparison of common points ~1 and ~2 indicates little or no temperature differential~ The same also applies to a comparison between common points ~3 and ~4. Now, a comparison between common points ~5 and t6 indicates a temperature dif~erential. A
temperature differential is also indicated between common points ~9 and ~10. However, note that the maximum temperature . , ~ '' ~.. ~ ,' ,, - ' J `, , . , , ' ' . . :
~912ZO
differential is detected at the antenna ~12 where the temperature differential between ~11 and ~lZ is on the order of 2 o5C~
Again, in FIG~ 23 direct comparisons of common point for common point are made. HoweYer, in an alternate embodiment o~
the invention each of the antenna sites may be compared with a common average. This is desired because a temperature differential does not necessarily indicate a tumor if there is a cold spot. It may simply indicate that there is an elevated temperature of good tissue in comparison with the cold spot.
Therefore, by a~eraging all of the breast temperatures this should eliminate all of the problems associated with detection of cold spots.
As indicated previously, by compressing the breast, one reduces the tissue thickness. This is particularly helpful in connection with the measurement of large breasts in which there may be difficulty obtaining proper measurements by surface contact without compression. It is also noted that with the double antenna arrangement, one is measuring ~rom opposing surfaces. This allows determination of depth, which again is particularly helpful in larger breasts, although it also applies to all breasts. For example, if a tumor is located midway between the two opposing antennae of a particulas brea~t, thè signal strength is approximately equal at both ~34 '',' . ', .' "'., ''' ~ ~9~220 antennae. However, if the tumor is offset, the degree of offset can be ~etermined by the signal strength at the two opposed antennae. By way of example, refer to PIG. 17 and the arrays 41 and 51. At the same breast, like opposed antennae positions may be sensed to determine the position of tumor therebetween. ~urthermore, by using opposed antenna arrays, this means that either side of a particular breast can be examined with a reduced path length by a factor of 2, because one is looking fro~ two opposing surfaces.
FIG. 24 is a schematic diagram illustrating some of the electronics that may be employed in providing some of the comparisons previously referred to. In FIG. 24 there are shown the arrays Al and A2 each of which have multiple antennae coupling to the processor 120. It is noted that the arrays ~1 and A? couple to a multiplexing switch 119 of conventional clesign. The output of the switch 113 couples to the radiometer R and the output of the radiometer couples to the stores 121 and 122. ~he radiometer R detects the respective temperature signals from the antennae and the processor 120 records these signals for subsequent processing.
The processor 120 may be a computer that has certain inputs coupled thereto by a keyboard for indicating whether one or the other breast is being examined. Thus, ~or example~ i~ it is assumed that the left breast is being examined then a .
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s, -;
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9 ~2z o particular pattern of storage occurs in devices 121 and 122 so as to provide points on the left breast that can be compared.
When the right breast is then compared like signals will be coupled to store 121 and 122 for the sake of discussion herein store ~1 in EI~. 24 may be considered as being associated with the left breast while store ~2 is associated with the right breast.
In FIG. 24 there is shown one comparator 124. It simply receives signals from each of the stores 121 and 122 for making a dir æt comparison which is the comparison i~lustrated in FIG.
23 between common points on each breast. Also illustrated in FIG. 24 is an averaging circuit 125 and a second averaging circuit 126. The averaging circuits take all of the locations associated with the left breast and average them and the averaging circuit 126 takes all locations associated witb the rignt breast and averages them. Also illustrated in FIG. 24 are two other comparators 128 and 129. The comparator 128 compares---the average with readings from the left breast and the comparator 129 compares the average with readings from the right breast. A further comparator may be used to compare the outputs from the comparators 128 and 129~
Aga-in, in summary it is desired to make comparisons between common points on each breast. This may be made on a direct comparison basis but preferably i8 made by comparing the , , . : .
.
;
~9~LX20 reading from an antenna with average breast temperature, for example, the co~parator 128 can provide such a reading.
In the mammography it is possible to detect the tumor mass and also the contrast with respect to surrounding tissue.
Mammography defines the location, size and structure of a tumor. On the other hand with regard to the use of microwaYe energy for detection, what can be detècted is actual thermal activity generally independent of size of the tumor. It i8 expected that this detection of thermal activity actually precedes the $ormation of mass and thus may give an early indication of the intended growth of a cancerous tumor. It is also noted that the antenna placements in accordance with the invention are preferably provided so that comparisons can be rnade between detection~ in accordance with the present invention and detections can be made by the presently used mammography techniques.
Having now described a limited number of embodiments of the present invention, it should now be apparent to those skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention as defined by the appended claims. For example, there i~ described herein~ antennae in the form of waveguide members. These antennae can be air filled as well as dielectrically filled. They may be provided with only a ``` ~1.291Z~O
dielectric window at the end of the waveguide. Furthermore, the waveguide ty~e antenna may be replaced by a printed antenna construction.
What is claimed is:
.
: .. , - .
FIG. 3 illustrates in dotted outline the antenna array 41 associate~ith housing 38 and also shows in cross-section the antenna array 51 associated with the housing 48. There are leads 76 c~pling from each of the antennae 40 of array 41.
These leads couple to a connector 77 and then there are output leads that couple from the housing 38. Similarly, there are leads 78 coupling from the antenna array 51 to a connector 79.
From the connector there are leads that couple out of the movable antenna housing 48.
FIG. 4 is a plan view taken along line 4-4 of FIG. 3. Thi~
.; . ~ ., ~ .
:
. ~29~20 illustrates the particular placement of the antennae 40 in a triangular shaped array all disposed within the cupped surface 39. FIG~ 4 also illustrates the coupling 77 and ehe coupling of leads out of the housing 38. FIG. 4 also illustrates the clamp 42 for clamping the housing 38 in position. In the particular embodiment illustrated as FIG. 4 the antenna array is for use with an intermediate size breast such as the aforementioned 5 1/2" breast. The particular array has a lower most row of three antennae spaced apart, a second row of two antennae staggered in relationship to the first row and a third single antenna altogether making the triangular shape as aforementioned.
Reference is now made to ~IG. 6 which is a rear elevation vi~.w partially in cross-section showing further details of the appa~atus illustrating the movable and rotational upper housing ~le.~nd the fixed lower housing 38. There is illustrated the r~at-ional clamp knob 64 and the knob 62 for setting the dijtance apart ~etween the housingsO FIG. 6 also illustrates the ~lamping or loc~ bars 68, spacers 80t and fiber washers 81. Pins 82 are disposed in association with the non-rotating washer 83.
.Reference is now made to F~G. 7 that illustrates a cross-sectional view with the two housings in confronting relationship and which the cupped surfaces 39 and 49 are in ., .
; , ; . ~,~ ;
~9~o facing relative relationship to each other. Therebetween there i~ shown a dotted outline a warming blanket 84 which is preferably used to warm the cupped surfaces prior to usage as will be described hereinafter. It is furthermore noted that each of the antennae 40 and each of the antennae 50 has a domed end 40A, 50A.
Reference is now made to FIG. 8 which is a cross-sectional view taken along line 8-8 of FIG. 7 showing further details of the afi~enna 40. This antenna is comprised of a section of waveguide 85 and a probe 86 coupling to the coaxial line 87.
The waveguide ~5 is preferably dielectrically filled as shown at 88 in FIG. ~. Also in FIG. 8 it is noted that there is clearly described the domed end 40A of the antenna.
The embodi~ent of the invention illustrated in FIGS. 7 and 8 is used in connection with breast sizes of 5 1/2" and 7n~
~or ~-larger breast of 9" size then it is preferred to use the a~tenna form illustrated in FIGS. 9~11. It is noted that the breast diameter may be determined from previously available mammo~graphy data. FIG. 9 shows the series of antennae 90 disposed in an array 91 covering an area that matches the size of a relatively larse breast identified as a 9" breast herein.
As noted in FIG. 99 these antennae are disposed in the same general pattern as previously illustrated in FIG. 4 in a first row of three antennae, a second row of two antennae and then -lB-.
.
~.~9~
followed by a single antenna disposed in a staqgered arrangement in a generally triangular array.
FIG. 10 is a cross-sectional view similar to that illustrated in FIG. 7 but for the large breast embodiment of the housing. Again, there is described in FI~. 10 the warming blanket 84 and dotted outline used to warm the ends of the antennae. The antennae 90 have domed ends 90A and the overlying antennae 92 have domed ends 92A. Again, these domed ends are for the purpose of preventing air pockets between the breast and the antennae. FIG. 10 also illustrates the cup surface 39 associated with housing 38 and the similar cup surface 49 associated with housing 48.
FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10 showing some further detail of the microwave antenna illustrating in particular the cupped surface 39, domed end 90A
and dielectric filling 94.
Thus, in this embodiment of the invention just described, there are two housings as in the em~odiment illustrated in FIG.
8 each i~cluding 6 antennae of generally rectangu1ar construction each comprising a section of waveguide and a probe for detecting signals from the waveguide. There i~ an array of antennae 91 associated with housing 38 and also an array 93 of antennae associated with the housing 4B. Each of these arrays as noted comprises six antennae each with domed surfaces.
'' . ' 1.29~L~20 ~ eference has been made hereinbefore to the embodiment of the invention in which two housings are used such as in the different positions of FIG. 1 and 2. Mention has also been made of a single antenna housing 30 having associated therewith, handle 35 as referred to in FIG. 12. PIG. 12 also shows the outline of a breast 96. FIG. 12 also shows portions of the apparatus described in FIG. 1 including the vertical post 26, support member 34, and knobs 62 and 64. FIG. 12 also shows in dotted outline an array 100 of antennae 98.
~ eerence is also made to ~IGS. 13 and 14. FIG. 13 shows the housing 30 with the antenna array 100 comprised of six antennae 98. Each of the antennae 98 may be of the construction previously described such as shown in the detail of.F~..B. The waveguide section thereof is preferably dielectrlcally filled and the waveguide sec~ion has a domed end 102. ~ array of six antennae are disposed in the circularly cuppea-s-~rface 104.
FIG..12 shows the placement of the breast compressed against the antenna array 100 this compression is brought ab~ut in this embodiment by virtue of the person being tested grasping the handle 35 and drawing the housing 30 against the breast to flatten the,breast and compress it so as to cover the entire antenna array. As indicated previously this form of the invention is employed in particular with small breasts tha~ may -~0-: - . . .,.. ~, , :
~.291~20 be too small to effectively compress between a pair of housings. Thus, instead a single housing is used with the associated handle 35 for providing compression directly against the breast.
Now, reference ~s made to FI~. 15 which shows a schematic circuit diagram of a microwave radiometer that may be employed in the system of this invention for taking temperature mea~urements. Preferably, a single radiometer is employed and readings are taken in succession from each of the antennae as will be described hereinafter.
With regard to FIG. 15, there is illustrated an input to the switch SWl from the receiver antenna such as from the antennae 40 or 50 as illustrated in FIGS. 2 and 3. The , . . .
microwave radiometer that is depicted may be of the DICKE
switch type. The radiometer desiqn substantially reduces the . . _ effects of short term gain fluctuations in the radiometer. The .
receiver input is switched by means of a switch SWl at a constant rate between the antenna and a constant temperature reference load. The switched, or modulated RF signal is therefore inserted at a point prior to RF amplification and as close to the antenna as possible; in turn, it is then amplified and coherently detected. The final output is proportional to the temperature difference between the antenna and the reference load.
... " , , - . . ..
', . " ,., '., ~, ' ' ` `, - - . ' ~ .. , . . _.
~;~9~ O
In FIG. 15 a second switch SW2~ referred to as a calibration switch, may also be employed. With this switch, the reference load as defined by the noise diode 36A and fixed attenuator 38Ao is compared with a base load 4QA rather than with the signal from the an~enna. If the base load is equal in temperature with the reference load, the DC output of the ra2iometer is thus nulled to zero~
The radiometer described herein employs at least one low noise RF amplifier in conjunction with a simple single ended square law detector rather than the more complex superheterodyne which employs a local oscillator and IF
amplifier. The square law detector of this arrangement minimizes the potential drift and noise associated with the superheterodyne approach. The conformance that comprises the radiometer are di~cussed in detail hereinafter.
With r2s~rd t~^the microwave radiometer schematic of FIG.
15, at its i~ t the-e ~s shown the connection which is pre~erably by way of a coax cable from the receiver antenna lapplicator aperture) to one input of switch S~ hls may be termed a calibration switch which is a solenoid-operated , mechan~cal single pole/-double-throw switch used to disconnect the antenna and in its place connect the base load 4QA by way of a second switch S~2. The switch SWl has an isolat~on or switching radio, of greater than 60 dB with a corresponding ' - . ~
1~9~2~) insertion loss of less than 0.1 dB. The switch SW2 is used in the calibration circuit to disconnect the base load and to insert in its place the calibrated noise source as represented by the ~ixed attenuator 38A and the noise diode 36A referred to hereinafter.
As indicated in FIG. 15, there are three ferrite isolators used in the receiver path. These are identified as isolators ISOL-l, ISOL-2 and ISOL-3. The first isolator, is located between the calibration switch S~l an~ the DICXE switch Sh'3.
Thi~ isolator is used to terminate the output of the reference load when the DICKE switch is in the low loss state. In this state, the reference or base load is circulated in the direction of the antenna which, in this case, functions as a ferriie isolator. ~he isolator ISOL-l employs a c:oaxial~to-waveguide transition. The insertion loss of this isol3~0r and the transition is less than 0.~ dB, with a corr~ nding isolation of greater than 2.3 dB.
The second isolator ISOL-2 in FIG. 15, is disposed between the switch SW3 and the first stage RF amplifier to maintain a constant load match to this amplifier. Any reflections from the RF amplifier would therefore be terminated in the isolator. Again, this isolator, which is a waveguide isolator with a coax-to-waveguide transition, has an insertion loss o~
less than 0.2 dB with an isolation o~ greater than 23 dB.
-~3 . . ., . ~. , , ~
.: ' "
1~9~L220 There is also provided in FIG. 15 a third isolator ISOL-3 which is located between the output of the first RP amplifier and the bandpass filter 44A. ~he purpose of this particular isolator is to present a constant load match to the output stage of the first RF amplifier, and also to present a matched input to the bandpass filter 44A.
A switchable ferrite circulator, designated switch SW3 in FI~. 15, forms the load comparison, or DICKE switch, function.
A ferrite device is preferred over a semiconductor approach primarily in view of the lower insertion loss, ~ypically les~
than 003 dB, and elimination of noise generated by the semiconductor junction over and above the measured insertion loss.
Br~efly, the device S~3 is a switchable ferrite junction circulator utilizing the remnant, or latching, characteristics of ~h-e Eerrite material. The principle of latchinq action îs 2~--fo-llows: Using the intrinsic properties of a hysteresis loop of a ferrite toroid, a transverse magnetic field is used across a portion of the ferrite exposed to an RF signal. The biasing field is actually the residual inductance of the ferrite toroid; therefore, the device needs no holding power and can be reversed tn polarity using merely enough energy to overcome the natural coercive force of the toroid.
For the system of this invention, the latching circulator ~24-has been constructed in wave~uide having a single ferrite element contained within the microwave circuit. The insertiOn loss is less than 0.3 dB, having isolation in excess of 20 dB.
The first-stage RF amplifier may be a four stage FET device constructed in microstrip with integrated biasing circuitry.
The noise figure of the first amplifier (M/A Canada amplifier Model No. ~C-2019) is 2.0 dB with a gain of 35 dB. The secon~
RF amplifier Amplica Model No. 3441CS~ has a noise figure of 2.6 dB, with an associated gain of 33 dB. In both instancest the noise figure includes the input ferrite isolator as depicted in FIG. 15. With the input and output VSWR at less than 1.5:1, the gain compression at signal levels of between -5~ dbm to -10 dbm is less than 0.1 dB.
~ n ~IG. 15 the filter 44A is a bandpass filter and the bandwtdth of the microwave radiometer is basically determined by tne`~andpass characteristics of this filter. The filter is dispos~d-dfter the first stage of RF ampli~ication to minimize . .
the imp~ct of the insertion loss of the filter on the overall system per-formance. The filter characteristics are chosen to minimize possible interference due to nearby microwave communications or radar band~. The ilter is preerably an 8-section bandpass ~ilter constructed in stripline. The pass band loss is less than 3 dB and the bandwidth is approximately 500 MHz.
,~ 1,- , ~29~2~0 As indicated in FIG. 15, there are basically two loads provided, a base load 40 and a reference load 42A. The load design is coaxial, employing a stainless steel R~ connector to provide thermal isolation between the load and the remainder of the system. The coaxial termination is containe~ within an insulated housing and utilizes an integrated heater and proportional control to maintain constant temperature. The absolute temperature of both the base and the reference loads is monitored and displayed on a digital temperature indicator (not shown).
The calibration circuit comprises a precision, solid state, noise source having an excess noise ratio, ENR of 33 dB. This allows noise to be injected into the receiver front end via the high isolation mechanical calibration switch. The output level of the noise source is reduced through the use of a precision calibrated pad (43.3 dB~. This calibration circuit is shown in FI~. 15 as including a fixed attenuator 38A and the noise diode 36A.
The lock-in amplifier 50A shown in FIG. 15 enables the accurate measurement of signals contaminated by broad band noise, power line pickup, frequency drift or other sources of interference. It accomplishes this by means of an extremely narrow band detector which has the center of its pass band locked to the frequency of the signal to be measured. Because -2fi-: , ~ ,' ' - . . . , `
. ' ' ' . . .'.
, ., ~ ~ 9 ~Z2~
of the frequency lock and narrow bandwid~h, large improvements in ~ignal-to-noise ratio are achieved. This allows the 6ignal of interest to be accurately measured, even in situations where it is completely masked by noise. In addition, the lock-in amplifier 50A provides the synchronous function associated with the DICKE switch i.e., the unit supplies the 100 Hz reference clock frequency to drive the ferrite switch driver.
The system is provided, of course, with a power ~upply comprising two 12-volt 50 amp maintenance freet lead-acid batteries in series, fused at 10 amps per battery. The outputs from the battery assembly include 12 and 24 volts~ These voltages are appropriately applied to the receiver and lock-in amplifier. There may also be provided a voltage converter and regulator;'' Status indicators may be employed for indicating operating voltages. The main operating switch may have three positions i'ncluding an on position, an off position and a "charged" po~ition. In the charged mode, a meter is used to monitor the charge current to the batteries which is limited to approximately 6 amps. With a 3-6 amp-hour discharge rate (a normal 12 hour operating mode), the recharge cycle is approximately 10-12 hours (overnight).
With the' system o~ the present invention thermal drift i~
essentially eliminated. This is the case because all antennae are positioned concurrently and all readings taken ... ~ .. .. . ...
- ' .
. . .
~ ~ 9 ~2 ~
substantially concurrently. Moreover, the antenna surface that the breast contacts is warmed so that the readings can be taken in ~ay 1 minute to say 1.5 minutes rather than waiting a substantially longer time for proper temperature stabilization. It is preferred to warm the cupped surfaces 39 and 49 and of course the associated antenna domed ends to a t~mperature on the order of body temperature. This may be carried out by means o~ a warming pad as has been illustrated in the drawings. The preferred temperature ~hat the cupped surfaces are raised to is in the range of 30C-34C. This gets the surfaces that the breasts are going to come into contact with close to human skin temperature.
As indicated previously, in the embodiment employing a single antenna housing once the antennae are warmed the person being examined can themselves press the antenna array against the breast and readings can be taken in approximately 1 to 1.5 minutes. In the other embodiment of the invention that is more universally used, the lower antenna housing is ~ixed in position and the upper antenna housing moves downwardly and is capa~le of pivoting as clearly indicated in FIGS. 2 and 3 of thls application to cause compression of the breast such as illustrated in dotted outline in ~IG. 2. It has been ~ound that the upper housing generally does not become horizontal but is instead moved to a position approximately as illustrated in -~8~
'~, ' , ' ' , ~1 ~9~20 FIG. 2 tilted at a slight anglè usually in the range of 10 -35. It has been found that it is preferred not to have the housings horizontal as this provides too much compression and discomfort regarding these breasts being examined. It is only necessary that the antenna array make good contact with the tissue and that there be no air gaps between the antenna and the tissue. It is also important that the antenna array be somewhat matched in size to the breast being examined so that all antennae are properly covered. Any air gaps will create a mismatch. Also, in accordance with the invention the domed antenna structure is important in assuring that air gaps or air pockets do not form.
Reference is now made to FIGS. 16-22 in connection with a . .
group of- schematic diagrams that illustrate each of the different types of antenna arrays and the associated patterns for each breast. In this regard, FIG. 16 relates t~ the single antenna--housing version illustrated in FIGS. 1 and 12-14 o~ the inVeD~iOn, FIGS. 17-19 show patterns associated with the dual antenna~housings for 5 1/2" and 7" breasts. Finally, FIGS.
20-22 illustrate patterns in association with a 9" breast. In FIGS. 17-22 the patterns are illustrated cranio-caudad oblique and lateral, respectively.
FIG. 16 illustrates the antenna array 100 at the top for the left side and at the bottom for the right side. This is in ! ' ' .
;' ~ 2 0 connection with a relatively small size breast considered to ~e a 4" breast. Also note in FIG. 1~ the medial markers M. Each of these arrays comprise six antennae identified as ~ 6.
It is noted in the array illustrated in FIG. 16 that four of the antennae, ~l, #2, ~3 and ~6 are grouped more closely together at the outside of the breast while ~4 and ~5 are grouped closer to the medial marker M.
Now, it is noted that in FIG. 16 the outermost antenna is ~1 both with respect to the left breast and the right breast.
This i~ so that the ~1 readings are compared with comparisons being made at common points on each breast. ~or example, the right upper outer antenna ~6 is compared with the left upper outer antenna ~6. Because when the breast is compressed against the antenna array the antennae are actually in different positions depending ~pon whether it is the left breast or the right breast, information is fed into the system so that the proper comparisons are made of a common point on each breast. ~t may be, two separate housings 30 may even be employed one f~r the left breast and one ~or the r~ght breast.
FIGS. 1~-19 illustrate schematically the antenna array placements for the dual arrays, these are the arrays previously referred to as arrays 41 and 51 in FIG. 7. Again, in, for example, FIG. 17 the location ~1 on the left side i8 compared with the location ~1 on the right side. The position of FIG.
7 . . , , . ', . ...
," ;' , ., ~ ~ 9 ~X ~ O
17 relates to the position of housings of FIG. 2~ Again, in connection with FIGS. 17-lg it must be remembered ~hat when one is observing both sides of the breast using six upper antennae and six lower antennae. Thus, the right outer upper antenna is compared with the same position on the left breast or in other words the left outer upper antenna. Because the breasts are inserted in the same direction between the antenna housings this means that the equipment must int~rpret whether a left breast or a right breast is being examined. It then senses the signals from the antennae in the proper manner so that the proper points are compared. For example, in FIG. 17 it is noted that antenna ~6 on the left side appears to be in line with antenna ~1 on the right side. However, the electronics in t:he system interp~ets the readings differently so that the both ~1 sites are compared between left and right sides.
FIG. 17 illustrates the detection and compression as being in the cranio-caudad diEection. FIG. 18 indicates the compression ano sensing being at the oblique direction. In F~G. 19 the sensin~ is done in the lateral position such as illustrated previously in FIG. 1.
FIGS. 20-22 describes similar arrangements in connection with the embodiment of the invention illustrated in FIG. 10.
This is for the larger breast employing arrays 91 and 93. Once again, comparisons are made between the same common points on : . , : , :
each breast. For example~ in FIG~ 20 the left upper outer antenna ~1 is compared with the right outer upper antenna tl.
When the breast is inserted into the position between the housings there may be in fact two different antennae that will be used for detecting these common points but the electronics interprets whether the left or right ~reast is being examined and then takes the appropriate reading from the appropriate antenna so that the common comparisons can take place.
In FIG. 20 the position is cranio-caudad. In FIG. 21 the patt~rn is illustrated as oblique. In FIG. 22 the pattern is lateral.
It,is further to be noted~that the compression that has been referred to previously is also believed to lead to ~umor enhancement. An elevated temperature is generally associated with the tumor due to the metabolic activity of the tumor. The cell~ are consuming energy and thus ge~erate heat. In a cancerous tumor the cells double faster and thus are more active ~nd generate more heat. Also, the tumor has generally poor vascularity and thus cannot dump the heat that good.
Thus, when the blood circulating about the tumor is also compressed this reduces the temperature of the surrounding t~ssue with respect to the tumor tissue. This thus tends to enhance the temperature differential between the tumor itself and the surrounding temperature.
~ ' ~ . . , - r ( ~z ~ 2 0 As indicated previously, it is des~red to compare the like or common locations between each breast to determine a temperature differential therebetween. It is also desired to have the capability of making a comparison ~etween a particular temperature at an antenna loca~ion for comparison with the average breast temperature. There is a possibility of cold spots in the breast and thus it is preferred to average the temperature throughout the breast and then make the comparison of the average with each individual reading.
Reference is now made to FIG. 23 which shows a microwave thermogram. Thls is in association with the embodiment of the invention employing five antennae illustrated at the left breast as antennae ~2t t4, ~6, ~8, ~10 and ~12. Associated with t~e right breast are antennae ~1, t3, #5, ~7, ~9 and ~11.
Also s~own this plot indicating temperature associated with r~ ~
each of the four numbered antennae. Also illustrated in FIG.
i .
23 is ~;,site 110 where a tumor exists. ~ith reference to the drawing it- it noted that, for example, a comparison of common points ~1 and ~2 indicates little or no temperature differential~ The same also applies to a comparison between common points ~3 and ~4. Now, a comparison between common points ~5 and t6 indicates a temperature dif~erential. A
temperature differential is also indicated between common points ~9 and ~10. However, note that the maximum temperature . , ~ '' ~.. ~ ,' ,, - ' J `, , . , , ' ' . . :
~912ZO
differential is detected at the antenna ~12 where the temperature differential between ~11 and ~lZ is on the order of 2 o5C~
Again, in FIG~ 23 direct comparisons of common point for common point are made. HoweYer, in an alternate embodiment o~
the invention each of the antenna sites may be compared with a common average. This is desired because a temperature differential does not necessarily indicate a tumor if there is a cold spot. It may simply indicate that there is an elevated temperature of good tissue in comparison with the cold spot.
Therefore, by a~eraging all of the breast temperatures this should eliminate all of the problems associated with detection of cold spots.
As indicated previously, by compressing the breast, one reduces the tissue thickness. This is particularly helpful in connection with the measurement of large breasts in which there may be difficulty obtaining proper measurements by surface contact without compression. It is also noted that with the double antenna arrangement, one is measuring ~rom opposing surfaces. This allows determination of depth, which again is particularly helpful in larger breasts, although it also applies to all breasts. For example, if a tumor is located midway between the two opposing antennae of a particulas brea~t, thè signal strength is approximately equal at both ~34 '',' . ', .' "'., ''' ~ ~9~220 antennae. However, if the tumor is offset, the degree of offset can be ~etermined by the signal strength at the two opposed antennae. By way of example, refer to PIG. 17 and the arrays 41 and 51. At the same breast, like opposed antennae positions may be sensed to determine the position of tumor therebetween. ~urthermore, by using opposed antenna arrays, this means that either side of a particular breast can be examined with a reduced path length by a factor of 2, because one is looking fro~ two opposing surfaces.
FIG. 24 is a schematic diagram illustrating some of the electronics that may be employed in providing some of the comparisons previously referred to. In FIG. 24 there are shown the arrays Al and A2 each of which have multiple antennae coupling to the processor 120. It is noted that the arrays ~1 and A? couple to a multiplexing switch 119 of conventional clesign. The output of the switch 113 couples to the radiometer R and the output of the radiometer couples to the stores 121 and 122. ~he radiometer R detects the respective temperature signals from the antennae and the processor 120 records these signals for subsequent processing.
The processor 120 may be a computer that has certain inputs coupled thereto by a keyboard for indicating whether one or the other breast is being examined. Thus, ~or example~ i~ it is assumed that the left breast is being examined then a .
.. j,., ., " " . " ~ .. ~, i ~ i . .
.j", .~ , .. . . . ..
s, -;
,~ j " - . , -:
9 ~2z o particular pattern of storage occurs in devices 121 and 122 so as to provide points on the left breast that can be compared.
When the right breast is then compared like signals will be coupled to store 121 and 122 for the sake of discussion herein store ~1 in EI~. 24 may be considered as being associated with the left breast while store ~2 is associated with the right breast.
In FIG. 24 there is shown one comparator 124. It simply receives signals from each of the stores 121 and 122 for making a dir æt comparison which is the comparison i~lustrated in FIG.
23 between common points on each breast. Also illustrated in FIG. 24 is an averaging circuit 125 and a second averaging circuit 126. The averaging circuits take all of the locations associated with the left breast and average them and the averaging circuit 126 takes all locations associated witb the rignt breast and averages them. Also illustrated in FIG. 24 are two other comparators 128 and 129. The comparator 128 compares---the average with readings from the left breast and the comparator 129 compares the average with readings from the right breast. A further comparator may be used to compare the outputs from the comparators 128 and 129~
Aga-in, in summary it is desired to make comparisons between common points on each breast. This may be made on a direct comparison basis but preferably i8 made by comparing the , , . : .
.
;
~9~LX20 reading from an antenna with average breast temperature, for example, the co~parator 128 can provide such a reading.
In the mammography it is possible to detect the tumor mass and also the contrast with respect to surrounding tissue.
Mammography defines the location, size and structure of a tumor. On the other hand with regard to the use of microwaYe energy for detection, what can be detècted is actual thermal activity generally independent of size of the tumor. It i8 expected that this detection of thermal activity actually precedes the $ormation of mass and thus may give an early indication of the intended growth of a cancerous tumor. It is also noted that the antenna placements in accordance with the invention are preferably provided so that comparisons can be rnade between detection~ in accordance with the present invention and detections can be made by the presently used mammography techniques.
Having now described a limited number of embodiments of the present invention, it should now be apparent to those skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention as defined by the appended claims. For example, there i~ described herein~ antennae in the form of waveguide members. These antennae can be air filled as well as dielectrically filled. They may be provided with only a ``` ~1.291Z~O
dielectric window at the end of the waveguide. Furthermore, the waveguide ty~e antenna may be replaced by a printed antenna construction.
What is claimed is:
.
: .. , - .
Claims (31)
1. Microwave breast tumor detection apparatus comprising:
a plurality of microwave receiving antennae, means for supporting said receiving antennae in opposed array conforming substantially in size to the breast being screened, means coupled from said receiving antenna arrays for detecting temperature readings correspond-ing respectively to the breast temperature at sites underlying the receiving antennae, said means for supporting including separ-ately disposed housings for supporting the respective opposed arrays, and means associated with said antenna supporting means for compressing the breast between said opposed arrays so as to reduce tissue thickness being examined.
a plurality of microwave receiving antennae, means for supporting said receiving antennae in opposed array conforming substantially in size to the breast being screened, means coupled from said receiving antenna arrays for detecting temperature readings correspond-ing respectively to the breast temperature at sites underlying the receiving antennae, said means for supporting including separ-ately disposed housings for supporting the respective opposed arrays, and means associated with said antenna supporting means for compressing the breast between said opposed arrays so as to reduce tissue thickness being examined.
2. Microwave breast tumor detection apparatus as set forth in claim 1, wherein said means for sup-porting said receiving antennae includes at least one housing having a cupped surface at which the antennae are supported.
3. Microwave breast tumor detection apparatus as set forth in claim 2, wherein said antenna array is substantially symmetric so as to provide relatively uniform breast coverage.
4. Microwave breast tumor detection apparatus as set forth in claim 3, wherein the antennae of the array number on the order of six antennae.
5. Microwave breast tumor detection apparatus as set forth in claim 3, wherein each antenna has a domed end at said housing cupped surface so as to pre-vent air pockets between the housing and breast.
6. Microwave breast tumor detection apparatus as set forth in claim 3, wherein each antenna com-prises a dielectrically-filled waveguide section.
7. Microwave breast tumor detection apparatus as set forth in claim 3, wherein said means for com-pressing includes a gripping bar associated with said housing.
8. Microwave breast tumor detection apparatus as set forth in claim 7, wherein said cupped surface is supported substantially vertically.
9. Microwave breast tumor detection apparatus as set forth in claim 1, further including means commonly intercoupling said separately disposed hous-ings to provide disposition of said opposed arrays in contacting breast position at respective opposite sides of the breast being screened, and means for compressing the breast between the housings including means for moving the housings together to compress the breast so as to reduce tissue thickness to thereby reduce blood circulation in the breast thus reducing the temperature of the tissue surrounding the tumor in comparison to the tumor temperature to thus enhance the temperature differential between the tumor site and surrounding tissue.
10. Microwave breast tumor detection apparatus as set forth in claim 9, wherein said means for sup-porting said antennae includes first and second hous-ings each having a cupped surface at which the first and second sets of antennae are supported, respec-tively.
11. Microwave breast tumor detection apparatus as set forth in claim 10, including means for commonly carrying said first and second housings with associ-ated cupped surfaces disposed in facing relative relationship.
12. Microwave breast tumor detection apparatus as set forth in claim 11, wherein said means for commonly carrying includes a support member means for supporting the first housing substantially horizontal and in fixed position.
13. Microwave breast tumor detection apparatus as set forth in claim 12, including means for sup-porting the second housing over the first housing from said support member means.
14. Microwave breast tumor detection apparatus as set forth in claim 13, wherein said means for com-pressing includes a carriage on said support member means and means for operating said carriage to bring the second housing toward the first housing to com-press the breast therebetween.
15. Microwave breast tumor detection apparatus as set forth in claim 14, including means for provid-ing pivotal adjustment and positioning of the second housing so that the second housing is displaced fur-ther from the first housing at a point remote from the support member means than at a point adjacent the support member means.
16. Microwave breast tumor detection apparatus as set forth in claim 15, including means for locking the second housing in an angular tilted position relative to the first housing.
17. Microwave breast tumor detection apparatus as set forth in claim 10, wherein each antenna array is substantially symmetric so as to provide relatively uniform breast coverage.
18. Microwave breast tumor detection apparatus as set forth in claim 17, wherein each antenna has a domed end at said housing cupped surface so as to prevent air pockets between the antenna and the breast.
19. Microwave breast tumor detection apparatus as set forth in claim 1, including means for averaging all breast temperatures and means for comparing each individual antenna temperature with the average.
20. Microwave breast tumor detection apparatus as set forth in claim 10, including means for compar-ing the temperature from like sites of each breast to detect a differential temperature therebetween.
21. A method for the detection of a cancerous tumor comprising the steps of, providing a plurality of receiving antennae, supporting these antennae in opposed arrays conforming substantially in size to the breast being screened, supporting the opposed arrays in respective support members, compressing the breast between said support members so as to reduce tissue thickness that is being examined, and detect-ing the temperature readings with the breast com-pressed corresponding respectively, to the breast temperature at sites underlying the receiving antennae.
22. A method as set forth in claim 21, including providing one array supported in an upper position and the other in a lower position so as to provide separate upper and lower antenna arrays with the breast being compressed therebetween.
23. A method as set forth in claim 22, wherein the breast is compressed only with sufficient force to provide coverage of all antennae of the array.
24. A method as set forth in claim 23, including comparing temperature readings from common locations on each breast.
25. A method as set forth in claim 23, including averaging breast temperatures and comparing each indi-vidual antenna temperature with the average.
26. A method as set forth in claim 21, including providing the opposed arrays as facing arrays sup-ported on either side of the breast with the breast being compressed therebetween and comparing signal strength from oppositely disposed antennae of each array to determine tumor depth therebetween.
27. A microwave breast tumor detection apparatus comprising:
a first plurality of microwave receiving antennae, a first housing supporting said first plurality of microwave receiving antennae in a first array conforming substantially in size to the breast being screened, a second plurality of microwave receiving antennae, a second housing supporting said second plurality of microwave receiving antennae in a second array conforming substantially in size to said first array, means coupled from said receiving antenna arrays for detecting temperature readings correspond-ing respectively to the breast temperature at sites underlying the receiving antennae, and means commonly intercoupling said first and second housings to provide disposition of said first and second antenna arrays in contacting breast position at respective opposite sides of the breast being screened and including means for moving the housings together to compress the breast so as to reduce tissue thickness to thereby reduce blood circu-lation in the breast thus reducing the temperature of the tissue surrounding the tumor in comparison to the tumor temperature to thus enhance the temperature differential between the tumor site and surrounding tissue.
a first plurality of microwave receiving antennae, a first housing supporting said first plurality of microwave receiving antennae in a first array conforming substantially in size to the breast being screened, a second plurality of microwave receiving antennae, a second housing supporting said second plurality of microwave receiving antennae in a second array conforming substantially in size to said first array, means coupled from said receiving antenna arrays for detecting temperature readings correspond-ing respectively to the breast temperature at sites underlying the receiving antennae, and means commonly intercoupling said first and second housings to provide disposition of said first and second antenna arrays in contacting breast position at respective opposite sides of the breast being screened and including means for moving the housings together to compress the breast so as to reduce tissue thickness to thereby reduce blood circu-lation in the breast thus reducing the temperature of the tissue surrounding the tumor in comparison to the tumor temperature to thus enhance the temperature differential between the tumor site and surrounding tissue.
28. A microwave breast tumor detection apparatus as set forth in claim 27, wherein said means for detecting includes separate means for obtaining tem-perature readings of subcutaneous temperature from oppositely disposed breast surface sites.
29. A microwave breast tumor detection apparatus as set forth in claim 28, wherein said first and second plurality of microwave receiving antennae are equal in number so as to provide matching sites from both sides of the breast being screened.
30. A microwave breast tumor detection apparatus as set forth in claim 29, including means for com-paring signal strength from oppositely disposed antennae of each array to determine tumor depth therebetween.
31. A method of detecting a breast tumor com-prising the steps of, providing a first plurality of microwave receiving antenna, supporting the first plurality of microwaves receiving antennae and a first array conforming substantially in size to the breast being screened, providing a second plurality of micro-wave receiving antennae, supporting the second plural-ity of microwave receiving antennae and a second array conforming substantially in size to said first array, detecting temperature readings corresponding respec-tively to the breast temperature at sites underlying the receiving antennae, disposing the first and second antennae arrays in contacting breast position at respective opposite sides of the breast being screened and moving the housings together to compress the breast so as to reduce tissue thickness to thereby reduce blood circulation in the breast thus reducing the temperature of the tissue surrounding the tumor in comparison to the tumor temperature to thus enhance the temperature differential between the tumor site and surrounding tissue.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US795,976 | 1977-05-11 | ||
| US79597685A | 1985-11-07 | 1985-11-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1291220C true CA1291220C (en) | 1991-10-22 |
Family
ID=25166927
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 522459 Expired - Fee Related CA1291220C (en) | 1985-11-07 | 1986-11-07 | Multiple antennae breast screening system |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS62161343A (en) |
| CA (1) | CA1291220C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113413136A (en) * | 2021-06-11 | 2021-09-21 | 明岁美(深圳)文化有限公司 | Breast screening system based on infrared thermal imaging |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0502651D0 (en) * | 2005-02-09 | 2005-03-16 | Univ Bristol | Methods and apparatus for measuring the internal structure of an object |
| JP5605783B2 (en) * | 2009-06-10 | 2014-10-15 | 国立大学法人静岡大学 | Diagnostic equipment |
-
1986
- 1986-11-07 CA CA 522459 patent/CA1291220C/en not_active Expired - Fee Related
- 1986-11-07 JP JP61265437A patent/JPS62161343A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113413136A (en) * | 2021-06-11 | 2021-09-21 | 明岁美(深圳)文化有限公司 | Breast screening system based on infrared thermal imaging |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62161343A (en) | 1987-07-17 |
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