SYSTEM AND PROCESS FOR PERFORMING PERCUTANEOUS BIOPSY WITHIN THE BREAST USING THREE-DIMENSIONAL ULTRASONOGRAPHY

Abstract: There is provided a system and process for performing percutaneous biopsy within a breast using three-dimensional ultrasonography comprising: a breast positioning means; a breast immobilization means; an ultrasonographic imaging means; a biopsy instrument positioning means; the breast immobilizations means, the three-dimensional ultrasonographic imaging means and the biopsy instrument positioning means positioned in a known relationship relative to each other; the breast immobilization means being employed to immobilize the breast and a lesion contained therein for imaging by the three-dimensional ultrasonographic imaging means; and the three-dimensional ultrasonographic imaging means being employed to assist an operator in positioning the biopsy instrument positioning means relative to the lesion and guiding a biopsy instrument percutaneously to the lesion.

Description: SYSTEM AND PROCESS FOR PERFORMING PERCUTANEOUS BIOPSY WITHIN THE BREAST USING THREE-DIMENSIONAL ULTRASONOGRAPHY BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to percutaneous medical procedures within the breast. More specifically, the present invention relates to a system and process for performing percutaneous biopsy and instrument guidance within the breast under the imaging and guidance of two-dimensional and/or three- dimensional ultrasonography. DESCRIPTION OF THE PRIOR ART Breast cancer poses a serious threat to the lives of Canadian women. According to the American Cancer Society, one in nine North American women will develop mammary carcinoma (American Cancer Society 1992). This figure has increased from one in twenty in 1940 and reflects a steadily increasing incidence of breast cancer over die last few decades. Breast cancer has shown the highest occurrence of all female cancers, and was the second highest cause of cancer death for women in 1990 and 1991 (Amer. Cancer Soc. 1991). For women aged between 35 and 54, breast cancer is the leading cause of death (Beatty 1992). In 1994, an estimated 17,000 breast cancers were detected in Canadian women, and 5,400 Canadian women died of this disease (NCIC 1994). Historically, breast disease has been detected and diagnosed using x-ray mammography. Mammography is not only widely available and relatively inexpensive, it has also generally been regarded to be die most sensitive single test available for breast cancer, with a detection rate of 90-95 percent (Frankl 1988, Castor, 1987, Moskowitz 1983, Baker 1982). Early detection and diagnosis have been shown to improve both the morbidity and mortality rates from breast cancer (Shapiro 1982, Morrison 1989, Tabar 1990). Diagnosis of detected focal abnormalities using mammography is based on morphological features of breast lesions such as boundary appearance and distribution of calcifications. Although some lesions can be specifically characterized in this way as either benign or malignant, a large number are radiographically indeterminate. In a large study (Frankl 1988), mammography yielded a false positive rate of 48 percent, and is reported to be even less accurate in characterizing the dense breast tissue of younger women or tissue with fibro cystic disease (Ashley 1989; Robbins 1973). In screening situations, the false positive rate for x-ray mammography may be as high as 75-90 percent (Holmberg 1987). However, a number of large trials have shown that the positive predictive value for non-palpable breast cancer detected by mammography is disappointing. These trials reported mat only 20-30% of non- palpable radiographically suspicious lesions are proven to be carcinoma by biopsy (Ciatto 1987, Hall 1988, Homer 1984, Meyer 1984, Rosenberg 1987, Holmberg 1987). In addition, many patients undergo prolonged follow-up with repeated mammograms and ultrasound for benign lesions. This was demonstrated in a large study, in which about 11 % of the 34,282 women followed had lesions which were found to be benign. Clearly, mammography has a high rate of false positive diagnoses, leading to unnecessary biopsies, unnecessary careful follow-up of many patients over periods usually 2 year or more, undue psychological stress, inefficient patient management, and increased health care costs. Improvements in the specificity of diagnosis (i.e. reduction in the false positive rate) would result in fewer unnecessary surgical biopsies performed, lower health care costs and better patient management. Development of noninvasive methods to further characterize indeterminate lesions demonstrated on mammography is therefore highly desirable. Adjunct imaging modalities have been shown to provide additional morphological and physiological information which cannot be obtained by mammography. Characterization of lesions using mammography in conjunction with ultrasound, for example, has been shown to be more accurate than diagnosis by mammography alone. This has particular application for women with dense breasts, where mammography has demonstrated a high rate of inaccuracy. Therefore, mere has been a long standing need to develop a percutaneous method of diagnosing breast diseases and which further allows for the treatment of the diseases to be performed percutaneously. Accordingly, the present inventors have determined that by employing three-dimensional ultrasonography in combination with two-dimensional imaging, breast lesions can be viewed in an entirely novel manner. The present invention preferably employs a three-dimensional imaging system as disclosed in U.S. Patent 5,454,371 and U.S. Patent Application no. 08/562,590, filed November 24, 1995, the contents of which are herein incorporated by reference. However, as will be understood by those of skill in the art, other three-dimensional ultrasonographic systems may be employed with the system and method of the present invention with similar success. Further to this end, the majority of breast lesions operated on typically result in a scar and significant deformity to die patient. While some percutaneous biopsy techniques are presently in use, they are generally time consuming and tedious. It is believed mat die system and method of me present invention will be quicker, provide greater accuracy and be significantly less damaging over conventional methods. Features of the present system include percutaneous access to lesions, rapid speed of performing the procedure, continuous feed-back relating to any complication mat may occur, and increased flexibility in different approaches to be made to breast lesions. SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel system and process for performing percutaneous medical procedures within the breast using three-dimensional ultrasonography which obviates or mitigates at least one of the disadvantages of the prior art. According to one aspect of the present invention, there is provided a system for performing percutaneous medical procedures within a breast using ultrasonography comprising: a breast positioning means; a breast immobilization means; an ultrasonographic imaging means; a medical instrument positioning means; said breast immobilization means, said ultrasonographic imaging means and said medical instrument positioning means positioned in a known relationship relative to each other; said breast immobilization means being employed to immobilize the breast and a lesion contained dierein for imaging by said ultrasonographic imaging means; and said ultrasonographic imaging means being employed to assist an operator in positioning said medical instrument positioning means relative to said lesion and guiding a medical instrument percutaneously to said lesion. Preferably the percutaneous breast medical procedures may include cryosurgery, photodynamic therapy, hyperthermia, radiation seed implantation, and alcohol ablation or injection of tissue toxic substances. Preferably, said percutaneous medical procedure is a biopsy procedure. Also preferably, said ultrasonographic imaging means is a three- dimensional ultrasonographic imaging system with two dimensional imaging capabilities. Also preferably, said ultrasonographic imaging means includes an articulated arm having an ultrasonographic transducer attached diereto, said articulated arm enabling movement of said ultrasonographic transducer in a plane parallel to said breast positioning means. Also preferably, said ultrasonographic imaging system includes a drive means for moving said ultrasonographic transducer across said breast. Also preferably, said drive means is a linear drive motor mounted to said ultrasonographic transducer. Also preferably, said medical instrument positioning means is mounted on a track which permits motion in a plane parallel to said breast positioning means and guides said medical instrument into said lesion in a plane ormogonal to a scanning beam emitted from said ultrasonographic transducer. According to another aspect of the present invention, uiere is provided a system for performing percutaneous biopsy within a breast using three-dimensional ultrasonography comprising: a breast positioning means; a breast immobilization means; an ultrasonographic imaging means; a biopsy instrument positioning means; said breast immobilization means, said three- dimensional ultrasonographic imaging means and said biopsy instrument positioning means positioned in a known relationship relative to each other; said breast immobilization means being employed to immobilize the breast and a lesion contained dierein for imaging by said diree-dimensional ultrasonographic imaging means; and said diree-dimensional ultrasonographic imaging means being employed to assist an operator in positioning said biopsy instrument positioning means relative to said lesion and guiding a biopsy instrument percutaneously to said lesion. According to anodier aspect of the present invention there is provided a process for performing percutaneous biopsy within a breast using three-dimensional ultrasonography comprising the steps of: i) positioning a breast with a breast positioning means; ii) obtaining an ultrasonographic image of said breast with an ultrasonographic imaging means to locate a lesion; iii) identifying said lesion and immobilizing said breast and said lesion with a breast immobilization means; iv) obtaining a three-dimensional image of said lesion with said ultrasonographic imaging means; v) with said three-dimensional image, positioning a biopsy instrument positioning means for guiding placement of a biopsy instrument in said lesion; vi) placing said biopsy instrument with said biopsy instrument positioning means percutaneously into said lesion under die guidance of subsequent ultrasonographic images; and vii) performing said breast biopsy witii ultrasonographic images. BRIEF DESCRIPTION OF THE DRAWINGS A presently preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a system for system for performing percutaneous medical procedures within a breast using ultrasonography in accordance widi an embodiment of the present invention; Figure 2A shows an elevation view of a breast positioning means in accordance widi the embodiment of Figure 1 ; Figure 2B shows a bottom view of the breast positioning means in accordance with die embodiment of Figure 1 ; Figure 3 shows a top view of an alternative breast positioning means in accordance widi the present invention; Figure 4A shows the operation of a breast immobilization means in accordance with me embodiment of Figure 1 ; Figure 4B shows the furtiier operation of a breast immobilization means in accordance with die embodiment of Figure 1 ; Figure 4C shows the operation of an ultrasonograph imaging means in accordance widi the embodiment of Figure 1 ; Figure 4D shows the operation of a biopsy instrument positioning means in accordance widi the embodiment of Figure 1 ; Figures 5A-5E are schematic representations of a split-ring type biopsy instrument guide in accordance with one embodiment of the present invention. Figures 6A-6C are schematic representations of a split-cylinder type biopsy instrument guide in accordance widi a second embodiment of me present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A system for performing percutaneous medical procedures within a breast using ultrasonography in accordance widi an embodiment of me present invention is indicated generally at 10 in Figure 1. System 10 generally comprises: a breast positioning means 14; a breast immobilization means 22, an ultrasonographic imaging means 24; and a biopsy instrument positioning means 32. The breast is a modified sweat gland located between the layers of the superficial fascia. Throughout most of its course it is directly beneadi the subcutaneous tissue and easily accessible. There is a significant portion, however, mat lies behind the anterior border of pectoralis major and extending into me axilla. In order to obtain access to virtually all of die breast tissue die present inventors have determined mat die best patient position is a prone position wid die breast lying dependent as indicated in Figure 2. Preferably, the angle of the shoulder should be perpendicular to die torso with die elbows supported and not weight-bearing. In this position, pectoralis major and also pectoralis minor are relaxed allowing full access to die mammographic tissue. Considering diat die patient will preferably be prone or modified prone, diere are at least two designs considered by die present inventors for breast positioning means 14. The first design, as shown in Figures 2A and 2B comprises a table formed from tiiree portions. The first portion 15 is die longest and will be generally parallel to die floor and extend from the feet of die patient to approximately the level of the umbilicus. At mis level there wdl be a second portion 16 joined to first portion 15 at an angle of approximately between 20° and 30°. This board will have two rounded apertures 17,17' within it to allow the patient's breasts to protrude in a dependent position. Each of these apertures will have a "trap-door" type arrangement (not shown) which will permit each breast to be pushed up out of die way when die trap-door is closed so diat only one breast protrudes d rough at any one time. Having two breasts protruding through d e table would generally interfere with access of the other apparatus required. A tiiird portion 18 of table 14 is attached to second portion 16 at approximately the level of the shoulders and is generally horizontal. Portion 18 allows the patient to position her head comfortably during the procedure. Preferably, die width of die upper table should be no wider than the average female's shoulders as die shoulders are preferably positioned at approximately 90° to the torso. A second design for breast positioning means 14 is anotiier table-type arrangement as shown in Figure 3. In mis embodiment, breast positioning means 14 is a generally key-shaped type arrangement where the entire torso of die patient is placed on a single flat board. The board narrows at die level of die breasts to allow support of the entire torso tiirough direct pressure primarily on die sternum. Widi this arrangement a hinge-type or sliding gate member will be provided to allow die non-biopsied breast to be elevated out of the way. Breast immobilization means 22 is employed for the following reasons: Firstiy, many lumps witiiin the breast are quite mobile and on trying to biopsy diem, me lesion may move away from any needle; secondly, if the breast is compressed, a significant amount of normal tissue can be pressed out of die way so diat only die suspicious area is biopsied widi a minimum of other tissue around it; tiiirdly, the application of pressure decreases the risk of significant haematoma formation and fourthly, narrowing die amount of normal tissue between die transducer and the lesion improves ultrasonographic visibility. Breast immobilization means 22 is preferably attached to die underside of table 14 but may also be mounted to e floor or a mounting plate parallel to the second portion of table 14 to make room for the otiier required equipment. A strong clamping mechanism mat allows little to no motion of immobilization means is preferred. As shown schematically in me Figures, die device itself preferably comprises two soft curved pads 23,23' . Preferably pads 23,23' are made of a sterilizable material and will be non-allergenic. Pads 23,23' are tiien connected togetiier by a sliding rod, track or rack and pinion type mechanism 24 and die like such diat at least one of the pads 23,23' is movable for compressing and immobilizing me breast. Movement of the at least one pad 23,23' can eitiier be by hand or by mechanical means such as a linear moor, hydraulic actuator or otiier suitable type mechanism similar to the mechanisms presently employed on a conventional mammographic table. It is contemplated diat the selection of an appropriate device would be apparent to one of skill in die art. Preferably, breast immobilization means 22 is mountable to table 14 in any direction so as not to interfere with die otiier required equipment. Lesions generally occur in the upper-outer quadrant but can occur in any quadrant and die achial location of the area of die breast being compressed will be dependent on where die suspicious area is. Ultrasonographic imaging means 24 includes several components preferably including a three-dimensional imaging system with dedicated graphics software and a graphical user interface. An ultrasonographic transducer 26 will be positioned in a scanning mechanism housing 27 as previously described in the previously incorporated by reference patent and patent application. The housing is attached to d e table using two articulated arms 28 and 29 which are employed to position me transducer over die breast. Arms 28 and 29 will allow movement in a plane parallel to me second portion of table 14 (two perpendicular directions botii of which will ε parallel to the table surface). This will allow the entire device to be suspended from breast positioning means 14, floor or other suitable surface but enable the entire breast to be scanned. The direction of scanning will be in an anteroposterior direction tiirough the breast. A biopsy instrument positioning means 32 is also be attached to table 14 and is positioned in such a manner such mat me relative position between positiomng means 32 and ultrasonographic imaging means 24 is known and referenceable. Positioning means 32 includes a split ring type biopsy instrument guide or a 270 degree split cylinder for holding and guiding die medical instrument. The modes of operation, and specifically die degrees of movement, of the breast immobilization means, tiie biopsy instrument positioning means and me ultrasonographic imaging means are shown schematically in Figures 4A, 4B, 4C and 4D respectively. The split ring type biopsy instrument guide is shown schematically in Figures 5A-5E. The guide comprises a pair of elongate clamps provided widi an aperture adapted to receive a biopsy instrument. Each clamp has an open position and a closed position, as shown in Figures 5E and 5D, respectively. The clamp is maintained in its closed position by means of a circular band which, when proximal the aperture, prevents the two halves of the clamp from opening. The split cylinder type biopsy instrument guide is shown schematically in Figures 6A-6C. The guide comprises a pair of complementary quonset-shaped holders, a first one of which is fixed widi respect to a positioning track. The second holder is rotatable widi respect to die first holder around die longitudinal axis of the first holder. The second holder is rotatable from a closed position shown in Figure 6B to an open position shown in Figure 6C. A biopsy instrument which is inserted along the lengtii of die first holder when open, is retained witiiin tiie guide when die second holder is rotated to die closed position. The biopsy instrument is effectively clamped in a known orientation widi respect to the positioning track. The process for preparing the patient for the biopsy and obtaining an ultrasonographic image for the purposes of determining biopsy instrument positioning will now be described. It is contemplated diat the lesion will first be localized eitiier clinically or witii two-dimensional ultrasonography or mammography prior to commencing me procedure. Immediately prior to starting die procedure die lesion wdl be scanned to assess its ultrasonographic visibility. As shown in Figure 2A, die patient is positioned prone on breast positioning means 14 witii the affected breast left in the dependent position through one of apertures 17,17' . The pectoralis major muscle relaxed in die manner previously described. Ultrasonographic transducer 26 is mounted in me housing 25. The breast is tiien wiped wid alcohol and transducer 26 is tiien positioned up against me breast. The Time Gain Compensation (TGC) curve of tiie associated ultrasound machine of ultrasonographic imaging means 24 will be optimized to show die lesion. Transducer 26 will then be moved to d e mid- portion of die motorized housing and die centre of the lesion will be lined up by watching die image on a monitor. Once this is done transducer 26 is moved within die housing to one end of its travel. On activation, all or a portion of die breast will be scanned. It should be noted diat while it may be possible to scan die breast manually, ti e present inventors have determined diat die best results are obtained when transducer 26 is attached to a drive actuated housing wherein the rate of die scan is controlled and extraneous movement is minimized. Furtiier to this end, while it is presently contemplated that movement of transducer 26 is accomplished a linear drive mechanism within the housing, it is furtiier contemplated diat simdar scanning results may be obtained moving transducer 26 in a tilted or rotational manner. In some patients it may be necessary to apply some surgical tape direcdy to the breast to flatten it out to allow ease of contact with the transducer. It is envisaged diat this will not happen very often. A three-dimensional scan is men obtained and a diree-dimensional volume image is constructed, viewed and checked to ensure tiiat the lesion is in proper position. The next step will involve application of breast immobilization means 22 to the breast in the vicinity of tiie lesion. The lesion will be compressed in a direction approximately perpendicular to die ultrasound beam. Preferably, an attempt should be made to force die lesion closer to die skin surface, i.e. , closer to transducer 26. Once tiiis has been done, die step previously described for performing a diree-dimensional ultrasonographic scan will be repeated. Once die three-dimensional scan has been completed, the software as described in the patent and patent application previously described as being incorporated herein by reference is applied to die diree-dimensional volume and the lesions is tiien viewed and/or manipulated in tiiree-dimensions. Suitable positions for acquiring the biopsies or positioning tiie needle will be planned out. This information will be conveyed initially by hand to die needle position located at 90° to the ultrasonographic transducer 26. Witii this information, biopsy instrument positioning means 32 will be positioned and a needle will subsequently be positioned manually. It is further contemplated tiiat direct computer feed-back of die needle position could be employed to automatically position the needle and a further refinement will be tiie application of robotics to not only reposition the needle positioned, but also to position die needle exactly witiiin the affected area. The insertion of the needle into die lesion will be done under direct guidance wherein the needle is imaged using conventional two-dimensional ultrasonography or diree-dimensional ultrasonography. It is important to note tiiat for optimal imaging and guidance, die needle should be inserted parallel to die long axis of die ultrasound transducer 26 or approximately perpendicular to the scanning plane. While die present procedure has been described witii respect to breast biopsy, other possible percutaneous breast medical procedures may include cryosurgery, photodynamic tiierapy, hypertiiermia, radiation seed implantation, and alcohol ablation or injection of tissue toxic substances. These procedures may be performed using die system of the resent invention widi minimal modification which would be apparent to tiiose of skill in die art. The present invention has been described widi reference to a presently preferred embodiment. Otiier variations and embodiments of die present invention may be apparent to tiiose of ordinary skill in die art. Accordingly, die scope of protection sought for die present invention is only limited as set out in the attached claims.

Claims: What is claimed is: 1. A system for performing percutaneous medical procedures witiiin a breast using ultrasonography comprising: a breast positioning means; a breast immobilization means; an ultrasonographic imaging means; a medical instrument positioning means; said breast immobilization means, said ultrasonographic imaging means and said medical instrument positioning means positioned in a known relationship relative to each otiier; said breast immobilization means being employed to immobUize the breast and a lesion contained tiierein for imaging by said ultrasonographic imaging means; and said ultrasonographic imaging means being employed to assist an operator in positioning said medical instrument positioning means relative to said lesion and guiding a medical instrument percutaneously to said lesion. 2. The system according to claim 1 wherein said medical procedure is a biopsy procedure. 3. The system according to claim 1 wherein said ultrasonographic imaging means is a tiiree-dimensional ultrasonographic imaging system with two dimensional imaging capabilities. 4. The system according to claim 3 wherein said ultrasonographic imaging means includes an articulated arm having an ultrasonographic transducer attached tiiereto, said articulated arm enabling movement of said ultrasonographic transducer in a plane parallel to said breast positioning means. 5. The system according to claim 4 wherein said ultrasonographic imaging system includes a drive means for moving said ultrasonographic transducer to obtain a breast ultrasonographic scan. 6. The system according to claim 5 wherein said drive means is a linear drive motor mounted to said ultrasonographic transducer. 7. The system according to claim 1 wherein, said medical instrument positioning means is mounted on a track which permits motion in a plane parallel to said breast positioning means and guides said medical instrument into said lesion in a plane ortiiogonal to a scanning beam emitted from said ultrasonographic transducer. 8. A system for performing percutaneous biopsy witiiin a breast using three-dimensional ultrasonography comprising: a breast positioning means; a breast immobilization means; an ultrasonographic imaging means; a biopsy instrument positioning means; said breast immobilization means, said three-dimensional ultrasonographic imaging means and said biopsy instrument positioning means positioned in a known relationship relative to each otiier; said breast immobilization means being employed to immobilize the breast and a lesion contained tiierein for imaging by said tiiree-dimensional ultrasonographic imaging means; and said tiiree-dimensional ultrasonographic imaging means being employed to assist an operator in positioning said biopsy instrument positioning means relative to said lesion and guiding a biopsy instrument percutaneously to said lesion. 9. The system according to claim 8 wherein said ultrasonographic imaging means is provided witii two-dimensional imaging capabilities. 10. The system according to claim 9 wherein said ultrasonographic imaging means includes an articulated arm having an ultrasonographic transducer attached tiiereto, said articulated arm enabling movement of said ultrasonographic transducer in a plane parallel to said breast positioning means. 11. The system according to claim 10 wherein said ultrasonographic imaging system includes a drive means for moving said ultrasonographic transducer to obtain a breast scan. 12. The system according to claim 11 wherein said drive means is a linear drive motor mounted to said ultrasonographic transducer. 13. The system according to claim 8 wherein, said biopsy instrument positioning means is mounted on a track which permits motion in a plane parallel to said breast positioning means and guides said biopsy instrument into said lesion in a plane orthogonal to a scanning beam emitted from said ultrasonographic transducer. 14. A process for performing percutaneous biopsy within a breast using tiiree-dimensional ultrasonography comprising die steps of: I) positioning a breast with a breast positioning means; ii) obtaining an ultrasonographic image of said breast with an ultrasonographic imaging means to locate a lesion; iii) identifying said lesion and immobilizing said breast and said lesion widi a breast immobilization means; iv) obtaining a three-dimensional image of said lesion witii said ultrasonographic imaging means; v) with said tiiree-dimensional image, positioning a biopsy instrument positioning means for guiding placement of a biopsy instrument in said lesion; vi) placing said biopsy instrument widi said biopsy instrument positioning means percutaneously into said lesion under die guidance of subsequent ultrasonographic images; and vii) performing said breast biopsy with ultrasonographic images.

Inventors: DOWNEY DONAL B, FENSTER AARON, DOWNEY, DONAL, B., FENSTER, AARON
Applicants: DOWNEY DONAL B, FENSTER AARON, LIFE IMAGING SYSTEMS INC, DOWNEY, DONAL, B., FENSTER, AARON, LIFE IMAGING SYSTEMS INC.
Application year: 1997
Main classification: A61B10
IPC codes: A61B8, A61B10, A61B17, A61B19