Abstract:
A computer controlled apparatus for detecting breast tumors by mechanically palpating in a full surface scan manner to detect even very small lumps or other anomalies. The patient is positioned on a fully adjustable bed and oriented relative the apparatus. A detection head mounted for movement in three dimensions is positioned above the bed. A palpation finger is brought into pressure contact with a sequence of small areas across the entire breast, palpating each area to measure tissue density. Concurrent with the palpation scan, a scan of breast color and temperature is conducted. A locator head positions the detector for the scan in a manner that assures repeatability of the palpation scan during each of a series of periodic examinations. This system detects very small lumps and allows easy, accurate, monitoring of suspicious areas over an extended time period.

Description:
FIELD OF THE INVENTION 
     This invention relates to apparatus and methods for detecting very small anomalous masses, in particular tumors, in the human breast. 
     BACKGROUND OF THE INVENTION 
     Recent findings indicate that one of eight women will develop breast cancer, the second leading cause of cancer death in women. Unopposed estrogen activity is an important pathogenic factor, with other risk factors including nulliparity, early menarche, late menopause, a family history of breast cancer, middle age and prior breast cancer. 
     The earliest indication of breast cancer generally is the occurrence of a painless lump, sometimes associated with nipple discharge and skin retraction. Later symptoms are generally due to metastases to bone, brain, lungs and liver. Early diagnosis may be possible through monthly self-examinations. Mammography has proven beneficial in early detection. 
     When a very small lump, &lt;2 cm, is detected, a biopsy is generally performed, followed by treatment when the lump is found to be malignant. This can range from a lumpectomy with possible radiation treatment of axillary nodes to a modified radical mastectomy with axillary node dissection. With early treatment, the five-year survival rate is about 85%. Without early detection, if distant metastasis occur, the survival rate may drop to 10% or less. 
     Early detection of lumps is thus essential. Monthly self-examinations are very desirable, followed by examination by a physician if any suspicious areas are detected. It is, however, difficult for an unskilled person to detect very small lumps or to do a thorough examination. 
     Periodic palpation of the breasts by a physician and mammography will often detect very small tumors. These examinations should be reasonably frequent, particularly in older women, in order to detect tumors before they can metastasize. However the cost of frequent examinations, plus the accumulated radiation exposure from frequent mammograms tend to limit frequency. In addition, mammography may miss very small tumors, especially in the dense breasts of younger women. Further, pregnant women should avoid exposure to radiation. 
     Thus, there is a continuing need for improved methods and apparatus for very early detection of very small breast lumps that could be malignant, while avoiding radiation exposure. 
     SUMMARY OF THE INVENTION 
     The above-noted problems, and others, are overcome in accordance with this invention by an apparatus for thoroughly palpating entire breasts in a continuous, automatic scanning manner, to detect changes in breast tissue physical characteristics such as tissue density, surface color the tissue, tissue temperature and, where anomalies are detected, mobility and size of the anomaly. 
     The overall system includes a bed upon which the patient lies face up and which includes means for precisely positioning the patient in the same position for each of a series of periodic examinations. A detection head is mounted on a carriage for movement in three dimensions adjacent to a patient on the bed. A locator head associated with the detection head controls the bed positioning means to position the breasts in precisely the same position as for prior examinations. A palpation means on the detection head includes a finger-like palpation end movable toward and away from the breast surface to palpate the breast in the same general manner as a physician. The palpation device is preferably mounted so as to be movable across the entire breast surface sequentially while maintaining the finger generally perpendicular to the breast surface. 
     Information sensed by the palpation device and position information from the detection head and palpation means are collected, stored and displayed in a conventional manner, such as is done with information from other systems such as computerized tomography and magnetic resonance imaging. The display will reveal any anomalies detected, so that further testing, such as through a biopsy, can be done. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Details of the invention, and of preferred embodiments thereof, will be further understood upon reference to the drawing, wherein: 
     FIG. 1 is a schematic elevation view of the entire anomaly detection apparatus; 
     FIG. 2 is a schematic plan view showing a patient positioned on the patient positioning bed; 
     FIG. 3 is a schematic elevation view of the detection head actuator; 
     FIG. 4 is a schematic elevation view of the detection head positioning means; 
     FIG. 5 is a schematic diagram of the locator head assembly; and 
     FIG. 6 is a schematic elevation view of the vertical positioning mechanism of the anomaly detection apparatus. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to FIG. 1 there is seen a carriage  10  mounted at a proximal end on a horizontal support  12  for movement therealong a detection head  14  (as detailed in FIGS. 3 and 4) is mounted at the distal end of carriage  10 . A locator head  16  (detailed in FIG. 5) is mounted to detection head  14  for movement therewith. Digital information from and to detection head  14 , locator head  16  and control commands to the various motors, limit switches and the like is passed between a computer center  17  as schematically indicated. Information will be received, stored, interpreted and displayed in the same manner as other medical scanning devices, such as CAT scans, MRI scans, etc. Three dimensional images can be viewed on a conventional computer monitor. If desired, images may be shown with different tissue density areas shown in different colors. Artificial intelligence techniques may be used to improve system performance. The combination of tissue density information as developed by palipatation and the ancillary local color and temperature information results in detection of much smaller tumors and the ability to easily track changes in discrete tissue areas. 
     Horizontal support  12  is mounted on a vertical support mechanism  18  (as detailed in FIG. 6) along which support  12  can move in a vertical direction. Horizontal support includes a traveler  20  that rides in bearings  22  along rods or tubes  24  that are secured at their ends to end blocks  26  and  28 . A lead screw  30  extends from a bearing  32  at end block  26  to a drive motor  34  at end block  28 . Lead screw  30  extends trough correspondingly threaded openings in walls  36  of traveler  20  so that traveler  20  will move to the right or left as the lead screw is rotated in one direction or the other. Conventional limit switches  37  prevent overtravel of traveler  20 . 
     Guide rods  38  extend vertically through end blocks  26  and  28  and a lead screw  40  extends vertically through end block  28 . These components are shown completely and discussed in conjunction with the discussion of FIG. 6, below. 
     Carriage  10  includes a base  42  secured to traveler  20 . A motor  44  within base  42  rotates a screw  46  that is threaded into an intermediate body  48  to raise and lower that body as the screw is rotated one way or the other. A pair of guide rods  50  extend through brackets  52  to guide movement of body  48 . A lower body  54  is secured to intermediate body  48  for rotation relative thereto. A motor  56  is mounted on intermediate body  48  with lower body  54  mounted on the motor shaft  56  for rotation with the shaft. 
     An arm  61  is pivotally mounted at pivot  62  on bracket  64  mounted on the distal end of lower body  54 . A motor  60  on lower body  54  drives a pulley  62  on arm  61  through a jackshaft  64 . 
     Thus, the entire carriage can be moved horizontally by horizontal support  12  and vertically by the vertical support of FIG.  6 . Lower body  54  of the carriage can be rotated through a full circle. Arm  61  carrying detection head  14  can be pivoted through at least 180°. This combination of movements permits detection head to be positioned in any desired position relative to any portion of a breast surface. 
     In order to perform a complete breast examination, a person lies face-up on a bed  62  mounted on a position adjusting assembly  64  as seen in FIG.  2 . The bed will be positioned generally below detection head  14  of FIG.  1 . 
     Bed  62  has a comfortably padded upper surface, with matrix boards  66  adjacent to the shoulders of person  68 . Conventional optical measuring means (not shown) can be provided to locate the exact positin of arms, shoulders and neck relative to the matrix board pattern during a first examination. Then, when the person  68  is again postioned on the bed  62  for a later examination, the optical system in conjunction with conventional software can again detrermine the person&#39;s position relative to matrix boards  66  and the position of the bed can be adjusted in accordance with stored location information to place the person in substantially the identical position as for the first examination. Further, if person  68  were to move during the examination, the optical system can detect and correct for the change in position. It is highly desirable that the person be positioned as identically as possible for each of the periodic examinations. 
     The underside of bed  62  includes conventional tubular bearings (not seen) through which horizontal guide rods  70  pass. A central threaded rod  72  engages end bearings  74  on assembly and passes through a conventional motor driven nut assembly  76 . As the motor driven nut assembly is rotated in one direction or the other, bed  62  will be correspondingly moved sideways. Similarly, a pair of guide rods  78  extend between end walls  80  of assembly  64 . Guide rods  70  and  78  are each arranged in a set of at least two parallel guide rods. A central threaded rod  82  passes through a conventional threaded block (not seen) secured to the underside of bed  62 . A motor  84  rotates threaded rod  82  to move the bed in either lengthwise direction, as desired. The overhead end blocks  26  and  28  (FIG. 1) are mounted on posts  85 , the lower portions of which are seen in FIG.  2 . 
     The operating structure of detection head  14  is detailed in schematic elevation view in FIG. 3. A removable connection  86  for main housing  87  mounting detection head  14  on arm  61 . Preferably, detection head  14  is rotatable relative to arm  61  by a motor  88 . 
     A detector housing  90  for palipatation finger  92  and sensor  94  for sensing distance, color and temperature is mounted on main housing  87  through arms  96  and  98 . Finger  92  is designed to act like a physician&#39;s palpating finger in a manual breast examination. Typically, finger  92  will be formed from a sturdy, disposable material, such as glass. 
     Sensor  94  includes a distance measuring mechanism, of the sort used in cameras and the like, for providing precise distances between the breast surface and the sensor. If desired a plurality of spaced range finders, such as the range finder conventional schematically indicated at  95 , may be used to assure that palipatation finger  92  is oriented perpendicular to the breast surface. 
     A conventional means for measuring the color of the breast surface being examined is included in sensor  94 . Typically, this can be a conventional prism for breaking up incoming light and refracting each color of light to an independent photo electric or photo resistive sensor. 
     Palipatation finger  92  is secured to the distal end of an shaft  100  that is slidable through housing  90  and pivoted at proximal end to the distal end of arm  102  at pivot point  104 . Arm  102  is rotatable about an axis  106  centrally located along arm  98 . The proximal end of arm  102  is pivotally connected to drive shaft  108  at pivot point  110 . When shaft  108  is moved axially by an actuator within actuator housing  112  (as detailed below in conjunction with the description of FIG. 4) shaft  100  and palipatation finger move a proportional distance in the opposite direction. As discussed below, a laser reader in reader housing  114  detects movement of shaft  108  and the feedback resistance to movement experienced by palipatation finger  92  when pressing against breast tissue. 
     An error correction sensor  116  is provided on housing  90 , cooperating with a member  119  mounted on shaft  108  to detect and correct positioning errors. It is possible that the moving components of the detection head mechanism shown in FIG. 3 may not be positioned correctly any time after coils  118  (FIG. 4) have been activated and repositioned. Resetting the position of the moving parts, e.g., detection head  90 , shaft  100 , arm  102 , and therefore palpation finger  92 , is accomplished by the first coil  118  at the left as seen in FIG.  4 . Slight changes in position of the breast skin, due to breathing or the like, is sensed by finger  92  and a corresponding position correction signal is sent to the leftmost coil  118  to correct for that displacement. While this precision is often not required, it is available if needed. 
     The internal components within actuator housing  112  and reader housing  114  are schematically illustrated in FIG. 4. A series of electromagnetic coils  118  are arranged in a uniformly spaced relationship along a central tube  120 . An end shaft  122  is axially secured to the proximal end of shaft  108  and extends into tube  120 . Shaft  108  slides in a sleeve  123 . 
     End shaft  122  is formed from a magnetic material so that when coils  118  are actuated sequentially, beginning with the coil adjacent to the end of shaft  122  fastened to shaft  108  the magnetic forces will tend to pull end shaft  122  into tube  120 . As seen in FIG. 2, this pulls shaft  108 , rotating arm  102  and extending shaft  100  and pressing palipatation finger  92  toward an adjacent breast. 
     The magnetic forces provide a rather “soft” pull so that breast tissue can stop the advance of palipatation finger  92  without severe compression. The distance the finger advances will be in proportion to the density of the tissue, with a lump of more dense tissue resisting penetration, so the distance the finger advances will be less. This arrangement of arm  102 , shafts  100  and  108  with magnetic coils  118  could be thought of as a weighing scale where breast tissue density corresponds to the object to be weighed and the magnetic actuator is the standard portion of weight placed on the other side of the scale. 
     In operation, the first coil  118  will be actuated, moving palpation finger  92  a predetermined distance. Typically the coil is powered up stepwise, at about 250 mv per step up to about 10 volts maximum. The pressure change per step is typically only around about 10 grams per mm 2  per step. If tissue resistance is low, the second coil  118 , and others in sequence, will be similarly actuated, further moving the finger. Eventually, tissue resistance will reach a predetermined level and the distance traveled by the finger will be measured, as detailed below, and the information transferred to conventional information storage means. 
     The mechanism for encoding and transmitting the palpation information to the storage and use station is enclosed in reader housing  114 . As seen in FIG. 4, a conventional laser optic card  124 , using technology as applied in musical compact disks but with a single straight track, is carried by shaft  108 . A laser card reader  126  reads the shaft position from the card  124  and transmits the encoded information to the information collection station. There, the information can be converted to machine language or any desired format for interpretation by conventional software systems of the sort used in CAT scan systems or other medical scanning systems. Any error or mechanical tilt is detected in real time by error correction sensor  116  that filters out any mechanical movement other than the desired palpation movement. 
     A typical laser card  127  of the sort used in reader  126  is schematically illustrated in FIG. 4 a . Card  127  is similar to a compact disk, having a series of reflecting areas  129  separated by non-reflective areas  131 . While non-reflecting areas  131  could be light absorbing, generally it is preferred that they be transparent so the impacting light will be passed through. A laser transmitter  133  directs a laser beam  135  against the patterned area of laser card  126 . When the laser beam  135  hits a reflecting area, reflected light is picked up by a receiver  137 . As card  127  is moved transversely, conventional software can count the pattern of reflection pulses to measure movement of shaft  106  and, ultimately, palpation finger  92 . The reflecting areas can be as small as about 0.001 mm for highly precise movement measurement. 
     An adjustment mechanism  128 , such as a threaded adjustment shaft acting similar to a turnbuckle, is provided to adjust the position of arm  108  relative to the array of electromagnet coils  118 . The maximum excursion of arm  108  is limited by pin  130  extending from shaft  108  and limit switches  132  The unit will thus sequentially test areas to provide a “picture” of the entire breast surface, revealing density changes indicative of tumors on a very fine scale, in a manner similar to the images produced in MRI, CAT and other physical scanning methods. 
     To provide the maximum consistency of results from one examination to the next, it is highly desirable that the person and the breasts be positioned as identically as possible for each examination. The movable bed arrangement shown in FIG. 2 aids, in cooperation with. Locator head  16  schematically illustrated in FIG. 5, provide accurate positioning by locating the position of a person on the bed and actuating the various carriage, bed and detection head movement mechanisms under computer control to locate the breast to be examined in substantially the same position it was in at the last prior examination. 
     A digital camera  134  provides a digitized image of the breast and patient in a matrix manner to supply sufficient data for the ongoing examination session and the preposition of the patient whenever a new image is required. A computer system can compare the original image to a subsequent image at the start of a subsequent examination so that the patient&#39;s position can be adjusted until the images match. 
     A white light source  136  is provided with a schematically illustrated focussing lens system including lens  138 , a lead screw  140  rotatable by motor  142  and threaded through a lens mount bracket  144  to focus a light spot on the breast surface. As the spot of light is moved transversely and focussed at different depths along the present, the scan can be saved in computer memory in a conventional manner to produce a three-dimensional image of the breast. 
     In addition, a laser scanner  146 , including a laser emitter  148  and a focussing system  150  for producing a small spot on the breast being examined may be used in the same way as the white light spot to create a three-dimensional image. Typically, a 680-820 mm, 0.0095 mw laser may be used, since that laser has sufficient power for imaging without damaging the skin. 
     A window  152  of glass or plastic that is transparent to the white light and laser light closes the bottom of locator head  16 . A similar window  154  covers the side of head  16  adjacent to camera  134 . 
     The mechanism for raising and lowering the entire carriage  10  as seen in FIG. 1 is illustrated in FIG.  6 . Vertical guide rods  38  extend from a sturdy base  156  to a top plate  158 . End blocks  26  and  28  carry horizontal support  12  (FIG. 1, omitted from this Figure for clarity) for vertical movement therealong. 
     A powerful motor  160  rotates a sturdy lead screw  162  threaded through block  28 . An upper limit switch  164  and a lower limit switch  166  prevent movement of horizontal support beyond desired limits. For a very strong, sturdy assembly, base  156  will rest on the floor or a sub-floor so that bed assembly  64  could be positioned within the frame formed by base  156 , top support  158  and guide rods  38 . 
     The image produced by either of these light spots produced at a first examination can be compared to an initial image produced at a later examination to adjust the breast position to substantially match the original position. This will aid in re-examining a suspicious spot or lump found in the initial examination during later examinations. 
     The three-dimensional images can be divided into a matrix of cubes or slices with geometric indicia (e.g., a cube might be identified as cube, 2,4,9 on an x-y-z axis basis) and locations can be directly compared between the light spot image and the finger palpation locations. 
     While certain specific relationships, materials and other parameters have been detailed in the above description of preferred embodiments, those can be varied, where suitable, with similar results. Other applications, variations and ramifications of the present invention will occur to those skilled in the art upon reading the present disclosure. Those are intended to be included within the scope of this invention as defined in the appended claims.