US20090156961A1 - Localization mechanism for an mri compatible biopsy device - Google Patents

Abstract

A localization mechanism, or fixture, is used in conjunction with a breast coil for breast compression and for guiding a core biopsy instrument during prone stereotactic biopsy procedures in both open and closed Magnetic Resonance Imaging (MRI) machines. The localization fixture can include a breast compression plate and a biopsy probe support plate for supporting a biopsy probe for movement along multiple perpendicular axes. The position of both the breast compression plate and the biopsy probe support plate can be adjustable along an axis which is generally parallel to a probe needle.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This divisional application claims priority to U.S. Ser. No. 10/273,445 filed Oct. 18, 2002 in the names of Tsonton et al., scheduled to issue as U.S. Pat. No. 7,438,692. The present application cross references and incorporates by reference copending U.S. Ser. No. 10/171,330, “LOCALIZATION MECHANISM FOR AN MRI COMPATIBLE BIOPSY DEVICE” filed on Jun. 12, 2002, the disclosure of which is hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
• The present invention relates, in general to devices for tissue sampling and, more particularly, to a device for positioning a biopsy probe with respect to a magnetic resonance imaging (MRI) device.
BACKGROUND OF THE INVENTION
• The diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other disorders has long been an area of intense investigation. Non-invasive methods for examining tissue are palpation, Thermography, PET, SPECT, Nuclear imaging, X-ray, MRI, CT. and ultrasound imaging. When the physician suspects that tissue may contain cancerous cells, a biopsy may be done either in an open procedure or in a percutaneous procedure. For an open procedure, a scalpel is used by the surgeon to create a large incision in the tissue in order to provide direct viewing and access to the tissue mass of interest. Removal of the entire mass (excisional biopsy) or a part of the mass (incisional biopsy) is done. For a percutaneous biopsy, a needle-like instrument is used through a very small incision to access the tissue mass of interest and to obtain a tissue sample for a later examination and analysis. The advantages of the percutaneous method as compared to the open method are significant: less recovery time for the patient, less pain, less surgical time, lower cost, less risk of injury to adjacent bodily tissues such as nerves, and less disfigurement of the patient's anatomy. Use of the percutaneous method in combination with artificial imaging devices such as X-ray and ultrasound has resulted in highly reliable diagnoses and treatments.
• Generally there are two ways to percutaneously obtain a portion of tissue from within the body, by aspiration or by core sampling. Aspiration of the tissue through a fine needle requires the tissue to be fragmented into small enough pieces to be withdrawn in a fluid medium. The method is less intrusive than other known sampling techniques, but one can only examine cells in the liquid (cytology) and not the cells and structure (pathology). In core sampling, a core or fragment of tissue is obtained for histologic examination, genetic tests, which may be done via a frozen or paraffin section. The type of biopsy used depends mainly on various factors present in the patient, and no single procedure is ideal for all cases. However, core biopsies seem to be more widely used by physicians.
• Recently, core biopsy devices have been combined with imaging technology to better target the lesion. A number of these devices have been commercialized. One such commercially available product is marketed under the trademark name MAMMOTOME™, Ethicon Endo-Surgery, Inc. An embodiment of such a device is described in U.S. Pat. No. 5,526,822 issued to Burbank, et al., on Jun. 18, 1996, and is hereby incorporated herein by reference.
• As seen from that reference, the instrument is a type of image-guided, percutaneous, coring, breast biopsy instrument. It is vacuum-assisted, and some of the steps for retrieving the tissue samples have been automated. The physician uses this device to “actively” capture (using the vacuum) the tissue prior to severing it from the body. This allows the sampling of tissues of varying hardness. The device can also be used to collect multiple samples in numerous positions about its longitudinal axis, and without removing the device from the body. These features allow for substantial sampling of large lesions and complete removal of small ones.
• Co-pending application Ser. No. 09/825,899 filed on Apr. 2, 1997, which is hereby incorporated herein by reference, described other features and potential improvements to the device including a molded tissue cassette housing permitting the handling and viewing of multiple tissue samples without physical contact by the instrument operator. Another described therein is the interconnection of the housing to the piercing needle using a thumbwheel, to permit the needle to rotate relative to the housing, the preventing the vacuum tube from wrapping about the housing. During use, the thumbwheel is rotated so that the device rotates within the lesion, and samples can be taken at different points within the lesion.
• In actual clinical use for breast biopsy the instrument (probe and driver assembly) is mounted to the three axis-positioning head of an x-ray imaging machine. The three axis-positioning heads is located in the area between the x-ray source and the image plate. The x-ray machines are outfitted with a computerized system which requires two x-ray images of the breast be taken with the x-ray source at two different positions in order for the computer to calculate x, y and z axis location of the suspect abnormality. In order to take the stereo x-ray images the x-ray source must be conveniently movable. The x-ray source therefore is typically mounted to an arm which, at the end opposite the x-ray source, is pivotally mounted to the frame of the machine in the region of the image plate.
• Recently, there has been a need for a hand held core sampling biopsy device. This need has been fulfilled by Ethicon-Endo Surgery in U.S. Pat. No. 6,086,544 issued on Jul. 11, 2000, which is hereby incorporated herein by reference. This aforementioned patent discloses a hand held MAMMOTOME™ that may be held approximately parallel to the chest wall of the patient for obtaining tissue portions close to the chest wall than may be obtained when using an instrument that may be obtained when using an instrument that is mounted is manipulated by the operator's hand rather than by an electromechanical arm. Thus, the operator may steer the tip of the handpiece on the MAMMOTOME™ with great freedom towards the tissue mass of interest. The surgeon has tactile feedback while doing so and can thus ascertain to a significant, degree, the density and hardness of the tissue being encountered. In addition, a hand held MAMMOTOME™ is desirable because the handpiece on the MAMMOTOME™ may be held approximately parallel to the chest wall of the patient for obtaining tissue portions closer to the chest wall than may be obtained when using an instrument that is mounted to an electromechanical arm.
• Recently, there has been a desire to use the above described biopsy devices with MRI imaging devices instead of x-ray imaging devices. However, existing medical biopsy sampling devices use small, multi-lumen probes extensively fabricated mostly if not entirely from metal. However, the ability to provide accurate minimally invasive diagnosis of suspicious breast lesions hinges on the size of the sample obtained and accuracy in placement of the sampling device.
• The metallic nature of these probes has many drawbacks. Typically these metal probes are electrically conductive and often magnetically weak, which interferes with their use under MRI guidance. The electrically conductive and magnetically weak nature of metal probes often work to create field distortions, called artifacts, on the image. The image of the lesion will show the metal probe, and this is problematic because the image of the probe can obscure the image of the lesion.
• The small sample size of conventional biopsy needles also presents a significant limitation due to the increase in the duration of the procedure. Due to the tendency for contrast agent to “wash out” of suspicious lesions, and the progressive increase in enhancement of surrounding non-malignant breast parenchyma, suspicious lesions may become indistinguishable to the breast parenchyma within a few minutes. This limits the number of samples that can be retrieved using conventional spring-loaded core biopsy needles under direct imaging guidance.
• A further problem not infrequently encountered during core needle biopsy is the development of a hematoma at the biopsy site during the procedure. An accumulating hematoma can be problematic during MRI-guided biopsy because residual contrast agent circulating in the hematoma can mimic enhancement in a suspicious lesion. In addition, the accumulation of air at the biopsy site can cause susceptibility artifacts that can potentially interfere with the fat-suppression MRI techniques at the biopsy site cavity.
• These limitations of conventional biopsy needles have led several authors to conclude that lesions should be at least 1 cm in diameter before imaging could confirm that the MRI-guided biopsy device was definitely within (as opposed to adjacent to) the suspicious target. However, the demand for minimally invasive MRI-guided core biopsy is greatest for small lesions because they are more common, more difficult to characterize on MRI grounds alone, and have the best prognosis if they are found to be malignant.
• Therefore, there has been a desire to have generally non-metallic (especially non-ferromagnetic) biopsy probe of the type described above to eliminate artifacts. These needs have been filled by co-pending and commonly-owned application Ser. No. 10/021,680, “AN MRI COMPATIBLE SURGICAL BIOPSY DEVICE” to Huitema et al filed on Dec. 12, 2001, the disclosure of which is hereby incorporated by reference in its entirety. The lack of undesirable artifacts for the disclosed hand-held biopsy device allows the accurate placement of the probe. Moreover, disclosed vacuum assist allows visualization of the lesion entering a bowl of the probe to confirm accurate placement, as well as avoiding problems associated with a hematoma or an air cavity. Moreover, the volume and ability to rapidly rotate the open cutting bowl of the probe allows for multiple samples in succession without removal of the probe. Thereby, the duration of the procedure is reduced.
• However, elimination of the artifact created by the metal probe entirely is also problematic because physicians rely extensively on some type of artifact to notify them as to where the tip of the probe is relative to the lesion. These needs have been filled by co-pending and commonly-owned application and Ser. No. 10/021,407, entitled “AN MRI COMPATIBLE BIOPSY DEVICE HAVING A TIP WHICH LEAVES AN ARTIFACT” to Rhad et al., filed on Dec. 12, 2001, the disclosure of which is hereby incorporated by reference in their entirety. Having a target in the cutter at the distal end of the probe helps avoid advancing the probe through the chest cavity as well as accurately placing the bowl of the probe adjacent to the suspicious tissue for drawing into the cutting bowl.
• While the aforementioned hand-held MRI compatible biopsy devices provide many advantages, opportunities exist for improvements and additional clinical functionality. For instance, the hand-held biopsy device presents a long, external handle that is inappropriate for closed magnet MRI machines. Furthermore, while the hand-held biopsy device allows great freedom in lateral and angular orientation, in some instances it is preferable to specifically position the biopsy probe. The MRI machine may provide very accurate stereotactic MRI-guided placement information that is only partially utilized in inserting the probe. In particular, the hand-held biopsy device is inserted through an opening in a compression plate, so some two-dimensional alignment is provided. However, the angle and depth of insertion the probe tends to vary, especially without continual reimaging of the probe during insertion, which is particularly inappropriate for closed MRI magnets.
• Consequently, a significant need exists for a device for accurately positioning an MRI-assisted biopsy device.
BRIEF SUMMARY OF THE INVENTION
• The invention provides an apparatus useful for positioning a biopsy probe.
• In one embodiment the invention provides a localization apparatus for use in a medical compression apparatus for positioning a biopsy probe. The localization apparatus comprises a compression member containing a plurality of apertures, the position of the compression member being adjustable along an axis for providing tissue compression. At least two generally parallel, spaced apart supports extend in a direction generally parallel to the axis. The apparatus also includes a biopsy probe support, the position of which is adjustable along the two spaced apart supports. The biopsy probe support is adapted to support a biopsy probe between the two generally parallel spaced apart supports for movement of the biopsy probe in two directions perpendicular to the axis. The apparatus can further comprise at least two generally parallel spaced apart supports for supporting movement of the biopsy probe in a direction perpendicular to the axis.
• In one embodiment, the invention provides a localization apparatus which includes a compression plate and a biopsy probe support plate. The compression plate can include a plurality of apertures sized and positioned to permit passage of a biopsy needle associated with the biopsy probe. The position of the compression plate can be adjustable for providing tissue compression. The biopsy probe support plate can extend generally parallel to the compression plate, and the biopsy probe support plate can be supported for movement relative to the compression plate. The biopsy support plate is adapted to support a biopsy probe assembly for movement in two mutually perpendicular directions (e.g. X and Z directions) which are transverse to the direction of movement of the biopsy support plate relative to the compression plate (e.g. Y direction).
• The present invention also provides a localization apparatus comprising a compression member and a biopsy probe support, wherein the biopsy probe support is supported for movement with respect to the compression member, and wherein an apparatus associated with the biopsy probe support is adapted to releasably engage a biopsy probe assembly and position the biopsy probe assembly in two mutually perpendicular directions (e.g. X and Z directions) which are transverse to the direction of movement of the biopsy probe support relative to the compression member (e.g. Y direction).
BRIEF DESCRIPTION OF THE FIGURES
• FIG. 1 is plan view of a biopsy instrument, mounting fixture, an Magnetic Resonance Imaging (MRI) breast coil fixture, and patient support table in working relationship outside the confines of an MRI machine.
• FIG. 2 is a plan view of a biopsy instrument, a localization fixture, partially cut away MRI breast coil fixture, patient support table, and in working relationship and configured for insertion into a MRI machine.
• FIG. 3 is a plan view of a localization fixture, partially cut away MRI breast coil fixture, patient support table, and a detached probe assembly of the biopsy instrument mounted to the localization fixture, in working relationship and configured for insertion into the MRI machine.
• FIG. 4 is an isometric view of the biopsy instrument disassembled into a biopsy instrument handle, probe housing, and probe.
• FIG. 4A is a frontal isometric detail view of an alternative needle tip of a biopsy instrument.
• FIG. 5 is an exploded isometric view of a biopsy instrument handle.
• FIG. 6 is an exploded isometric view of the probe of the biopsy instrument ofFIG. 4.
• FIG. 7 is a transverse cross section of the probe of the biopsy instrument ofFIG. 4 along lines7-7.
• FIG. 8 is an enlarged isometric view of the interface between the handle and probe housing illustrating the visual confirmation elements that indicate the position of the distal end of the cutter.
• FIG. 9 is a fragmentary plan view in partial section of the distal portion of the handle and probe housing and assembly, illustrating the disconnect feature with the cutter retracted.
• FIG. 10 is a fragmentary plan view in partial section of the distal portion of the handle and probe housing and assembly, illustrating the tolerance take-out feature and the disabled disconnect feature when the cutter is advanced.
• FIG. 11 is an isometric view of the biopsy instrument with the handle portion disconnected from a tower/bracket localization fixture and probe assembly.
• FIG. 12 is an isometric view of the biopsy instrument mounted to the tower/bracket localization fixture ofFIG. 11.
• FIG. 13 is an exploded isometric view of the tower/bracket localization version of the localization fixture and probe assembly of the biopsy instrument.
• FIG. 14 is a side elevation view of the biopsy instrument in partial section to illustrate a tower/bracket support for stabilizing the handle and probe assembly of the biopsy instrument.
• FIG. 15 is a side elevation view of the dual tower support version of the localization fixture positioning a detachable probe assembly with its dual lumens closed by a vacuum conduit and an obturator stylet.
• FIG. 16 is an isometric view of the biopsy instrument mounted to a dual tower localization fixture.
• FIG. 17 is an isometric view of the slide plate of a localization fixture guiding a scissors support in a lowered position for vertically orienting a biopsy instrument.
• FIG. 18 is an isometric view of the slide plate of a localization fixture guiding the scissors support in a raised position for vertically orienting a biopsy instrument.
• FIG. 19 is a sequence of clinical operations for using the detachable MRI-guided biopsy instrument ofFIG. 1 in both open and closed MRI machines.
• FIG. 20 is an isometric view of a tip protector mounted onto a needle tip of the detachable probe assembly ofFIG. 11.
• FIG. 21 is an isometric detail view of the trip protector ofFIG. 20.
• FIG. 22 is an isometric view of one embodiment of a localization mechanism according to the present invention.
• FIG. 23 is an isometric view of an alternative embodiment of a localization mechanism according to the present invention.
• FIG. 24 is an isometric view of a biopsy mount employing a ball detent mechanism for releasably engaging a biopsy probe assembly.
• FIG. 25 is a cut away isometric view of a three position locking clamp.
• FIG. 26 is an isometric illustration of the localization mechanism ofFIG. 22 illustrating sliding a compression plate along a Y axis for compressing tissue.
• FIG. 27 is perspective illustration of the localization mechanism ofFIG. 22 showing a compression plate locked into position upon movement of a biopsy probe support plate relative to the compression plate along the Y axis.
DETAILED DESCRIPTION OF THE INVENTION
• FIGS. 1 through 21 and the accompanying description are taken from the above referenced U.S. patent application “Localization Mechanism for an MRI Compatible Biopsy Probe Device” Ser. No. 10/171,330 filed Jun. 12, 2002.
• FIG. 1 depicts a corebiopsy instrument system10 that is vacuum assisted, detachable, and compatible with use in a Magnetic Resonance Imaging (MRI) machine, such as the depicted closedMRI machine12. In the illustrative embodiment, the corebiopsy instrument system10 includes an MRI-compatible biopsy tool14 that is selectably attached to a localization mechanism orfixture16 to accurately and rapidly perform core biopsies of breast tissue with a minimum of insertions of a biopsy probe. A control module (not shown) senses encoder position signal and switch signals from thebiopsy tool14 and provides mechanical and vacuum power to thebiopsy tool14 viapower cord18.
• With reference toFIGS. 1-2, a patient20 is lying prone upon a patient support table22, depicted inFIG. 1 as removed from a magnet bore24 of theMRI machine12. The patient's chest rests upon atop surface26 of achest support28, thetop surface24 havingopenings30,32 for allowing the patient's breasts to hang downward for imaging and treatment. With particular reference toFIG. 2, theright opening30 is depicted with thelocalizer fixture16 laterally positioned to cooperate with a medial compression plate (not shown) to longitudinally fix and compress the patient's right breast. Antenna elements (not shown) are placed about theopening30 to detect radio frequency (RF) signals emanated from breast tissue induced by a strong magnetic field from the MRI bore24. Thechest support28,localization fixture16, and antennas are generally termed abreast coil34.
• Thebiopsy tool14 includes abiopsy handle36 that attachable to aprobe assembly38. Thelocalization fixture16 accurately positions theprobe assembly38 for stereotactic MRI-guided biopsy procedures for a specific biopsy site location for adistal tip40 of theprobe assembly38. This location is identified by an X-axis coordinate that is horizontal and longitudinal with respect to the patient (depicted as right to left inFIGS. 1-2). A Z-axis is defined as the vertical height, with the X and Z axis orthogonally defined on alateral compression plate42 of thelocalization fixture16, thelateral compression plate42 cooperating with the medial compression plate (not shown) to fix and compress the patient's breast. This location is also defined in terms of depth of insertion, or Y-axis, which is depicted as up and down in theFIGS. 1-2. A probeassembly mounting device44 connects to aprobe housing46 of thebiopsy tool14.
• The mountingdevice44 includes alignment positioning guides (described in more detail below) to orient theprobe housing46, and hence theprobe assembly38, to the desired X-Y-Z coordinate. For instance, adepth slide48 allows mounting of theprobe assembly38 with thedistal tip40 extends outside of theopening30 andlateral compression plate42. Thereafter, theprobe assembly38 is guided along the Y-axis by thedepth slide48 while maintaining the selected X-Z-axes coordinates. In addition, the mountingdevice44 advantageously supports the biopsy handle36 when attached to theprobe assembly38 as depicted inFIG. 2 to maintain the angle of insertion of theprobe assembly38. Theprobe housing46 provides access to the interior of theprobe assembly38 via a vacuumlumen access conduit50 for draining fluids, inserting fluids such as anesthetics.
• FIG. 3 depicts the corebiopsy instrument system10 with the biopsy handle36 removed and thedepth slide48 moved inward to allow insertion of the patient support table22 into the narrow confines of the MRI magnet bore24. Moreover, the surgeon may take full advantage of the stereotactic coordinates provided by theMRI machine12, even if using a closedmagnetic bore24. In particular, the stereotactic derived coordinates may be used even if not actively imaging theprobe assembly38 during insertion. Thelocalization fixture16 enables the surgeon to manually insert theprobe assembly38 in depth with an indication of current depth. The surgeon is given tactile feedback while doing so and can thus ascertain to a significant degree the density and hardness of tissue being encountered. In addition, with theprobe assembly38 maintained in the correct location after insertion, theprobe assembly38 provides access for other diagnostic and therapeutic tools and fluid treatments.
• Alternatively or in addition, a Y-axis adjustment mechanism may be incorporated into thelocalization fixture16 to provide mechanical advantage, thereby achieving a controlled and deliberate insertion of theprobe assembly38. Moreover, the Y-axis adjustment mechanism may incorporate a frictional, ratcheting or locking feature to prevent inadvertent movement of theprobe assembly38 after placement at the desired biopsy location. Examples of such Y-axis adjustment include but are not limited to a thumb wheel in geared communication between the probeassembly mounting device150 and thelocalizer support frame126.
• FIG. 4 depicts thebiopsy tool14 with the biopsy handle36 depicted as readily attached to theprobe housing46, which in turn is readily attached to theprobe assembly38. Theprobe assembly38 includes a malecylindrical mating portion52 presenting a central cutter opening54 on a proximal end that is aligned with the longitudinal length of acutter lumen56 of anelongated needle58. Thecutter lumen56 communicates with asample port60 laterally presented near aneedle tip62 at the distal end of theneedle58. Theneedle tip62 is for penetrating the soft tissue of a surgical patient. Theneedle tip62 is sharpened and is preferably made from an MRI compatible resin such as ULTEM or VECTRA. In the illustrative embodiment, theneedle tip62 is a three-sided pyramidal shaped point, although theneedle tip62 configuration may also have other shapes and/or inserts. In addition, as in the aforementioned application Ser. No. 10/021,407, entitled “AN MRI COMPATIBLE BIOPSY DEVICE HAVING A TIP WHICH LEAVES AN ARTIFACT”, the illustrative embodiment advantageously includes a material that leaves a small, but not troublesome artifact on an MRI scan.
• FIG. 4A depicts aneedle tip62′ having a conical shape with a distally presentedX-shaped slot63 for receiving a pointed, sharpenedblade65 that reduces the probe insertion force into tissue. Theblade65 could be made of titanium, stainless steel, nitinol, aluminum, Elgiloy, ceramic, etc. It will be appreciated that other shapes of sharpenedblade65 may be used, such as a single pointed surface in a distally presented single slot rather than two perpedicularly crossed, pointed surfaces as depicted.
• It will be appreciated that a cutter element or an obturator stylet is advanced inside thecutter lumen56 to block thesample port60 during insertion. Once theneedle58 is positioned, thesample port60 is exposed to allow tissue to enter. In particular, a vacuum may be presented to a “sample bowl” inside thecutter lumen56 near thesample port60 by applying vacuum power through avacuum chamber lumen64 that communicates along the longitudinal length of theneedle58 to the malecylindrical mating portion52. In particular, a series of small holes allow gas and fluid to enter thevacuum chamber lumen64 from thesample port60 but prevent tissue samples from entering.
• Annular rings66 about thecylindrical mating portion52 grip and seal to an interior of a femalecylindrical mating portion68 on theprobe housing46. Between annular rings, a proximal vacuum port (not shown inFIG. 4) communicates with a vacuum passage (not shown) in theprobe housing46. The engagement between themating portions52,68 advantageously allows rotation of theneedle58 with athumb wheel70 annularly presented near the proximal end of theneedle58. The radial opening presented by the annual rings66 maintains communication between the vacuum passage in theprobe housing46 and thevacuum chamber lumen64 regardless of radial orientation of theneedle58. Thereby, thesample port60 may be presented to tissue at any and all radial positions about the distal end of theneedle58. With the assistance of vacuum, a large volume of tissue may be selectably drawn into the sample bowl for biopsy sampling.
• Theprobe housing46 includes laterally presented attachment prongs72 for mounting to thelocalization fixture16. In addition, theprobe housing46 presents a proximally directedcuboidal engagement member74 with longitudinally aligned vertical andhorizontal grooves76 forflanges78 from thebiopsy handle36. Theprobe housing46 also receives hooked lockingtabs80,82 on the distal engaging end of the biopsy handle36 for selective locking and unlocking under the influence of a pair of opposing depression grips84,86 attached torespective tabs80,82. The biopsy handle36 includes asample window88 for extracting any tissue sample withdrawn from thecutter lumen52 under the influence of a vacuum passing through the cutter, as described in more detail below.
• FIG. 5 depicts a disassembled biopsy handle36 that contains the means for translating and rotating acutter90 within thecutter lumen56. It will be appreciated that two rotating mechanical power sources are presented to the proximal end of the biopsy handle36 through thepower cord18 to provide the independent translation and rotation motions. These two rotating mechanical power sources enter through acord opening92 defined between aremovable shell94 and abottom shell96, the two held together by screws. Theremovable shell94 is removed when assembling apower cord18 to thehandle36. Alower gear housing98 is supported upon thebottom shell96 and cooperates with atop shell100 to constrain movement of anelongate drive screw102, an elongateaxial screw104 andcutter carriage106. In particular, bothscrews102,104 are allowed to rotate, positioned parallel to one another and the longitudinal axis of thecutter lumen56. Eachscrew102,104 is driven by a respective power source from thepower cord18. Thedrive screw102 passes through thecarriage106 and interacts with corresponding ridges therein to impart a longitudinal translation corresponding to the direction and rate of rotation of thedrive screw102.
• In some applications, a single rotary power source may be used as an alternative to two independent rotating mechanical power sources. A transmission mechanism at the biopsy handle36 may convert the single rotary power source into the two motions, translation and rotation. As yet another alternative, the single rotary power source may directly supply both a translation and rotary motion. Such a translating and rotating power cable would be coupled to thecutter90 to directly control its movement.
• Thecutter90 is an elongate tube with a sharpened distal end for cutting tissue presented within the distal end of thecutter lumen56. The proximal end of thecutter90 includes acutter gear108 that is exposed through agear window110 of thecarriage106 to mesh with theaxial screw104 for axial rotation of thecutter90. Atissue remover111 is a tube that is fixedly aligned with the longitudinal axis to enter the proximal end of thecutter90. Thetissue remover111 extends up to thesample window88 and has a vacuum selectably applied to it by the control module. Thus, when thecutter90 is retracted, vacuum from thetissue remover111 draws the sample to the distal end of thecutter90 for retraction to thesample window88, whereupon the sample encounter thetissue remover111 and is dislodged for exiting thebiopsy tool14.
• Thecarriage106 includes distally projectedguides112,114 that advantageously take-out slack between biopsy handle36 and theprobe housing46, as well as providing indicia to the surgeon as to the depth of translation of thecutter90. Taking out slack between the assembled parts of thehandle36 andhousing46 advantageously minimizes the deadzone length of the distal end of theneedle58. Thecutter90 should completely translate past thesample port60 in order to reliably cut a sample. To ensure a full cut, thecutter90 should translate the maximum distance expected for the assembly. If variation exists in manufacturing tolerances between the engagement components, then a further distance has to be included in thecutter lumen56 distal to thesample port60 to accommodate the over-travel. Thereby, theneedle tip62 must be advanced farther than desirable in some instances, preventing placement of thesample port60 near critical body tissues. At or near full travel, theguides112,114 contact theprobe housing46, causing movement of thehousing46 to its maximum, distal position. Thus, critical dimensioning to minimize tolerance build-up is simplified.
• FIG. 5 also depicts abrace116 andbrace arm118 that are employed in one version of thelocalization fixture16 to support the weight and maintain the alignment of thehandle36. Thereby, flexure of the assembly is avoided that may place a load on theprobe assembly38, and thus unwanted movement of theneedle58 from the desired biopsy site location.
• FIGS. 6-7 depict theneedle58 ofFIG. 4 and described more fully in the aforementioned application Ser. No. 10/021,680, entitled “AN MRI COMPATIBLE SURGICAL BIOPSY DEVICE”. In particular,elongated needle58 is formed from aleft body member120 and aright body member121 on either side of the longitudinal axis. The edges of thehalves120 and121 are gated for easy part filling, and the edges are stepped with ridges that allow the twohalves120 and121 to attach together with ease. The twohalves120,121 are adhesively attached to one another. Acutter tube liner122 is inserted between the twohalves120,121 to provide a smooth surface for thecutter90, especially by preventing adhesive from entering thecutter lumen56 during assembly.
• FIG. 8 shows an enlarged view of the engagement of thehandle36 to theprobe housing46, with theadvanced cutter90 evident through thewindow88. In addition, theguides112,114 are advanced almost into contact with theprobe housing46, indicating that the distal end of thecutter90 is approaching its furthest translation. Theguides112,114 contact theprobe housing90 when at or near this extreme to take-out any tolerance. Indicia on the side of theguides112,114 may be referenced by the surgeon to determine the position of the cutter. Also shown in more detail is hooked lockingtabs80,82 entering theprobe housing46, thethumb wheel70 used to rotate theneedle80, and the vacuumlumen access conduit50 used to evacuate or otherwise access thevacuum lumen64.
• FIGS. 8-10 show that eachgrip84,86 includes a respective inwardly projectingmember124,125 that contact theguides112,114 when thecutter90 is distally advanced, thereby preventing removal of thehandle36. InFIG. 9, thecutter90 is retracted, allowed the depression of thegrips84,86, unlocking the hooked lockingtabs80,82 from theprobe housing46. InFIG. 10,cutter carriage106 is advanced, theguides112,114 are contacting theprobe housing46, thereby removing any longitudinal gap between the hooked lockingtabs80,86 and theprobe housing46.
• FIGS. 11-14 depicts alocalization fixture16 that includes means for accurately positioning theprobe assembly38 and supporting thebiopsy handle36. In particular, alocalizer support frame126 is formed from thecompression plate42 in a hinged, orthogonal relation to ahorizontal slide plate128, both laterally attached to one another bygussets130,132.Rods134,136 horizontally pass through the compression plate to adjustably attach to the medial compression plate (not shown) for compressing the patient's breast. Apertures, depicted as parallel rows ofslots138, in thecompression plate42 are provided to obtain access to a desired biopsy site location while providing enough remaining structure in thecompression plate42 for adequate contact with the patient's breast. Alternatively, the apertures may be a series of holes aligned both vertically and vertically, parallel columns of slots, or a large opening of other shapes. As yet a further alternative, portions of thecompression plate42 may be permeable to allow an aperture to be formed as needed.
• The desired biopsy site location is stereotactically determined during an MRI scan with reference to afiducial marker140 that presents a small artifact. Thefiducial marker140 is contained within afiducial marker holder142 that may be placed at a convenient location on thecompression plate42, accurately placed with reference to indents spaced along theslots138. Alternatively, the fiducial marker may be embedded or affixed to thecompression plate42.
• Thelocalizer support frame126 defines and provides the guide for positioning theprobe assembly38. The X-Y-Z axes are defined with regard to theslots138 andcompression plate42. In particular, the vertical dimension, or Z-axis, and horizontal dimension, or X-axis, are defined by the surface of thecompression plate42. The depth dimension, or Y-axis, is defined as distance away from the plane of thecompression plate42. Thehorizontal slide plate128 includes laterally aligned front andback rails144,146 for setting the X-axis coordinate.Horizontal indicia148 along the front rail144 give the surgeon an accurate measurement of the position of a probeassembly mounting device150.
• A first version of the mountingdevice150 is depicted that uses a singlevertical pedestal152 to position and support theprobe assembly38. In addition, the biopsy handle36 is supported by abrace116 connected to the proximal underside of thehandle36 to ahandle support rod156 that is slid through arod hole158 to the corresponding side of thevertical pedestal152. The appropriate height for thebrace116 is determined by selecting one of a range of slots arrayed along the underside of the handle, thereby pivoting thebrace116 about abrace arm118 whose first end slidably pivots within aslot162 in the middle of thebrace116 and second end attaches to the distal end of thehandle36.
• With thehandle36 detached from theprobe assembly38 as depicted inFIG. 11, anobturator stylet164 is slid into thecutter lumen56 to close thecutter port88. Thestylet164 may have radially-oriented through holes near its distal end to maintain fluid communication between thevacuum lumen chamber64 andcutter lumen56. Alternatively, thestylet164 may be partially withdrawn, allowing thecutter port88 to be in fluid communication with theconduit50
• Aslide166 includes a grooved underside to horizontally slide onrails144,146 of theslide plate128. Theslide166 also includes acentral channel168 oriented in the Y-axis depth dimension to guide thepedestal152 as it slides in the Y-axis direction. Sufficient range of motion in depth is achieved with apivoting depth slide170, aligned and pivotally attached to theslide166. With thepivoting depth slide170 in its lowest, horizontal position, thepedestal152 may be slid outward sufficiently for theprobe assembly38 to be out of thecompression plate42. With thepedestal152 distally slid onto theslide166, thepivoting depth slide170 may be pivoted upward or otherwise removed.Depth indicia172 along thecentral channel168 give the surgeon an indication of the insertion depth of theprobe assembly38.
• Avertical slide174 slides on thepedestal152 for vertical positioning along the Z-axis, with a measurement provided byvertical indicia176 on thepedestal152.Holes178 on each lateral side of thevertical slide174 allow mounting of theprobe housing46 on either side by insertion of attachment probes72.
• FIGS. 15-16 depict a second version of the mountingdevice150 that uses a secondvertical pedestal180 in lieu of a brace assembly to support thehandle36. Theprobe housing46 is also depicted as attached to the opposite side of the firstvertical pedestal152. A secondvertical slide181 of the secondvertical slide180 advantages contacts the firstvertical slide174, as shown inFIG. 16, so that setting the vertical height for both is accomplished in one step. Eachvertical slide174,181 moves in a ratchet fashion against its respectivevertical pedestal152,180, and thus remains in position after being separated from one another as shown inFIG. 15. Moreover, the close nesting of the twovertical pedestals174,180 enhances the ability to minimize the proximal displacement of thelocalization fixture16 when used within the close confines of a closed MRImagnetic bore24. It will be further appreciated that the secondvertical slide181 includes a shaped area that engages the underside of thehandle36 in such a way as to correctly align thehandle36 at the same X-axis horizontal dimension as theprobe assembly38.
• FIGS. 17-18 depict a third version of the mountingdevice150 wherein theslide166 andpedestal152 are replaced with ascissors table assembly182 that includes afirst slide184 for horizontal movement on theslide plate128. Adepth slide186 is nested within atop channel188 of thefirst slide182. With particular reference toFIG. 18, a pair of scissors braces190 are extended when drawn together with ascrew192, thereby elevating thedepth slide186 with respect to thefirst slide184. It will be appreciated that the third version of the mountingdevice150 advantageously provides a level support for both thedetachable probe assembly38 as well as the biopsy handle36 without having to perform two vertical adjustments, as well as not having to perform two separate attachments for each of thehandle36 andprobe assembly38.
• FIG. 19 depicts a sequence of operations, ormethod200, for performing an MRI-guided breast core biopsy that accurately and quickly performs a core biopsy even in a closed MRI. Moreover, the method takes full advantage of the stereotopic location information rendered from the MRI scan to position an MRI compatible core biopsy probe without the necessity of continuous imaging of the distal tip of the biopsy probe.
• Prior to performing a clinical breast biopsy, the equipment is initialized to ensure proper function. Thus, inblock202, the probe that comprises a needle, thumb wheel and housing is assembled with the handle. The assembled biopsy tool is connected via a power cord to a control module and the system is powered up, initiating power up logic in the control module (block204). Parameters for rotation speed and translation distances are loaded. If the control module determines that the system has not been powered up recently, such as 60 minutes, then initialization logic is performed. Thus, translational drivetrain initialization is performed (block206); rotational drivetrain initialization is performed (block208); and vacuum system initialization is performed (block210). If initialization is not required, then blocks206-210 are bypassed.
• Then, the patient's breast is immobilized in the localization mechanism (block212) and the patient is moved into the MRI magnet bore (block214). An MRI scan is performed to stereotopically locate suspicious tissue with reference to a movable fiduciary marker on the localization mechanism (block216). For a closed MRI magnet bore, the patient is then removed (block218), which is not necessary for an open bore. Anesthesia is administered prior to the minimally invasive vacuum assisted core biopsy procedure (block220). Using the X-Y-Z positioning capabilities of the localization mechanism, the positioning guides on the localization mechanism are positioned for insertion to the predetermined biopsy site (block222).
• Optionally, insertion may be enhanced by use of an insertion tool installed through the probe assembly38 (block224). For instance, an ultrasonic cutting tip, extender, and outer tube assembly may be inserted through theprobe assembly38 through a slot in theneedle tip62, or exiting from thesample port60 to be snapped onto theneedle tip62. This could be accomplished with a housing on the ultrasonic device that is configured to snap onto theneedle58, similarly to how a trocar obturator snaps onto the trocar cannula. Then, the ultrasonic tip is energized prior to insertion into the patient.
• The probe assembly is mounted on the localization mechanism (block226) at the designated X-Z coordinate and with the mounting device withdrawn along the depth axis. The cutter lumen is sealed with an obturator stylet (block228), if not otherwise sealed by a tool in block224. The vacuum lumen may be similarly sealed (e.g., stopcock attached to vacuum lumen access conduit50) or be used to aspirate fluid and tissue during insertion. Then the probe is advanced along the Y-axis, guided by the localization mechanism to avoid misalignment (block230). Once in place, if an insertion enhancement tool was installed in block224, then this tool is withdrawn through the cutter lumen of the probe assembly (block232).
• With the probe in place, various fluid transfers may advantageously take place through the probe assembly (block234). For example, vacuum may be applied through the vacuum lumen with the sample port exposed to drain any hematoma or air bubble formed at the biopsy site. Treatment fluids may be inserted directly to the biopsy site, such as anesthesia or MRI contrast agent. If the patient is to be scanned in a closed magnet bore, then the patient is moved back into the bore for scanning (block236). In addition, vacuum may optionally be applied to the biopsy site to draw in suspicious tissue into the bowl of the sample port for confirmation prior to cutting the sample (block238). Then, the MRI scan is performed to confirm placement of tissue in the bowl of the probe assembly, and adjustment of the probe assembly placement and re-scans are performed as required (block240).
• Sample mode is selected through the control module to perform the sequence of steps to translate and rotate the cutter according to predetermined settings, with vacuum assist to draw in the sample and to retract the sample along with the cutter to the sample window (block244). If more samples at this biopsy site are required for diagnostic or for treatment purposes (block246), then the thumb wheel is rotated to reorient the sample port to another angle (block248), and sample mode is performed again by returning to block244.
• After the core biopsy is performed, the probe assembly provides an excellent opportunity for other minimally invasive diagnostic procedures and treatments without the necessity for another insertion. If the biopsy handle is installed, such as in an open MRI magnet bore, the handle is removed so that the detachable probe assembly may be accessed (block250). Examples of tools that may be inserted through the probe assembly include: (1) gamma detectors; (2) energized tunneling tips to reduce tunneling forces; (3) inserts to aid in reconstruction of removed tissue (e.g., one or two sided shaver inserts); (4) spectroscopy imaging devices; (5) general tissue characterization sensors {e.g., (a) mammography; (b) ultrasound, sonography, contrast agents, power Doppler; (c) PET and FDG ([Flourine-18]-2-deoxy-2-fluoro-glucose); (d) MRI or NMR, breast coil; (e) mechanical impedance or elastic modulus; (f) electrical impedance; (g) optical spectroscopy, raman spectroscopy, phase, polarization, wavelength/frequency, reflectance; (h) laser-induced fluorescence or auto-fluorescence; (i) radiation emission/detection, radioactive seed implantation; (j) flow cytometry; (k) genomics, PCR (polymerase chain reaction)-brca1, brca2; (l) proteomics, protein pathway}; (6) tissue marker sensing device; (7) inserts or devices for MRI enhancement; (8) biochips on-a-stick; (9) endoscope; (10) diagnostic pharmaceutical agents delivery devices; (11) therapeutic anti-cancer pharmaceutical agents delivery devices; (12) radiation therapy delivery devices, radiation seeds; (13) anti-seeding agents for therapeutic biopsies to block the release of growth factors and/or cytokines (e.g., chlorpheniramine (CPA) is a protein that has been found to reduce proliferation of seeded cancer sells by 75% in cell cultures); (14) fluorescent tagged antibodies, and a couple fiber optics to stimulate fluorescence from a laser source and to detect fluorescence signals for detecting remaining cancer cells; (15) positive pressure source to supply fluid to the cavity to aid with ultrasound visualization or to inflate the cavity to under the shape or to reduce bleeding; (16) biological tagging delivery devices (e.g., (a) functional imaging of cellular proliferation, neovacularity, mitochondrial density, glucose metabolism; (b) immunohistochemistry of estrogen receptor, her2neu; (c) genomics, PCR (polymerase chain reaction)-brca1, brca2; (d) proteomics, protein pathway); and (17) marking clips.
• Then, a tissue marker is inserted through the probe assembly so that subsequent ultrasonic, X-ray, or MRI scans will identify the location of the previous biopsy (block252) and the probe is removed (block254).
• FIGS. 20-21 depict atip protector260 that advantageously protects theneedle tip62 of theprobe assembly38 prior to insertion into tissue and simplifies localization of theprobe assembly38 in some instances. Furthermore, thetip protector260 does not interfere with pre-clinical setup procedures (e.g., testing for vacuum leaks). In particular, thetip protector260 includes anattachment member262 with clips onto theneedle58 without obstructing thesample port60. A distal portion of the tip protector completely encompasses theneedle tip62 with a protection member, depicted as ahemispheric disk264, that may be placed in contact with a patient's breast without discomfort. In addition, in some applications thehemispheric disk264 may be comprised of or include an MRI artifact producing material, such as those described above. Since thehemispheric disk264 is MRI scanned outside of the patient's breast, a stronger artifact may be presented to aid in quickly locating the artifact without obscuring the suspected lesion.
• With a fiducial marker integrated into thetip protector260, there is potentially one less step in the localization process for operators that prefer to position fiducial marker at the closest insertion point to a suspected lesion prior to insertion. Procedurally, with thetip protector260 in place, the operator would attach theprobe assembly38 onto thepedestal152 and move theprobe assembly38 up against the breast tissue in the vicinity of where they believe the suspicious tissue to be, based on an earlier diagnostic image. Next, when the distance from this fiducial marker to the lesion is calculated, the “delta” distances are based on where the probe is currently positioned. There is a fixed offset along the Y axis to account for the distance from the fiducial to the middle of the bowl. Theattachment member262 accurately locates thehemispheric disk264 so that this Y-axis offset is predictable. This would be more intuitive because the delta positions are from where the probe is currently located.
• FIG. 22 provides an isometric schematic illustration of an embodiment of afixture mechanism316 according to the present invention. Thefixture mechanism316 can include abase318, a movablebreast compression plate342 having apertures for accommodating a biopsy needle (apertures in the form ofparallel slots338 inFIG. 22), and aprobe support plate352. Theprobe support plate352 can be supported to move independently of thebreast compression plate342 in the Y direction. A biopsy probe assembly438 (including needle with distal tip440) can be supported onprobe support plate352 to move relative to theprobe support plate352 in the X and Z directions, as described in more detail below. Thebiopsy probe assembly438 can be releasably attached to aprobe assembly mount320, such as by a spring loaded mechanism (e.g. ball detent) or other biasing mechanism for reducing clearances between theassembly438 and the mount320 (in order to improve positional accuracy of the probe). Probeassembly mount320 in turn can be supported onsupport plate352 to permit movement ofmount320 with respect to supportplate352, as described more fully below.
• Still referring toFIG. 22,probe support plate352 can includeplate side portions353 which are laterally spaced apart in the X direction. Abottom plate portion355 and atop bridge357 extend between theside portions353 and together with theside portions353 define an opening in thesupport plate352 through which a portion of theprobe assembly438 can extend.
• Compression plate342 is supported on slide shafts372 (which can be rigidly attached to or otherwise fixed relative to the base318) to translate relative to the base318 in the Y direction. TheCompression plate342 can be supported bybushings374A (or other suitable bearings) for permitting sliding of theplate342 onshafts372. The bushings can be disposed inbosses347 which extend fromside portions343.Bushings374A can extend alongshafts372 to also be disposed within a locking mechanism associated withshaft372, such as releasable clamp locking mechanisms discussed below.Shafts372 can include splines, a non circular cross-section or have other anti-rotation features to prevent rotation of the shaft with respect to theplate342 and for carrying torsional loads.
• Alocking mechanism376A can be associated with eachsupport shaft372 to releasably fix the position of thecompression plate342 in a desired Y location along theshafts372. A suitable locking mechanism is a toggle clamp manufactured by DE-STAC-CO Industries of Madision Heights, Mich. Other suitable locking mechanisms for releasably fixing theplate342 at a desired location along theshafts372 include, without limitation, friction locks, set screws, over center clamps, and spring loaded clamps. In one embodiment, a locking clamp can include a three position lever, wherein in an upright position the lever unclocks the clamp, in a horizontal position the lever locks the clamp, and wherein the lever can be depressed against a biasing spring to a third position to unlock the clamp while the lever remains depressed.
• The movablebreast compression plate342 can includeplate side portions343 which are laterally spaced apart in the X direction. Theplate342 can include abridge347 andribs349 which extend laterally between theside portions343 to provide apertures (slots338 inFIG. 22) for permitting passage of the biopsy needle in the Y direction. Alternatively, the apertures can be provided in the form of an array or grid of openings, and the apertures can be formed in a separate insert that is attached toplate342.
• The movablebreast compression plate342 engages twoshafts382 atbushings374B.Bushings374B are shown disposed inbosses344.Bosses344 extend laterally outwardly from eachplate side portion343 ofcompression plate342.Breast compression plate342 can slide in the Y direction relative toshafts382. Accordingly,breast compression plate342 is supported to slide relative to bothshafts372 andshafts382 in the Y direction.Shafts382 are generally parallel to, or collinear, withshafts372, andshafts382 have ends which can be fixed to probesupport plate352. In the embodiment inFIG. 22,shafts382 are cantilevered frombosses354 which extend laterally outwardly from eachplate side portion353 of thesupport plate352. Sliding movement ofshafts382 with respect toplate342 results in motion ofplate352 with respect toplate342 in the Y direction. A lockingmechanisms376B can be associated with eachshaft382 to releasably fixbreast compression plate342 with respect shaft382 (and also with respect to plate352) in the Y direction.Shafts382 can have splines, non circular cross sections, or otherwise incorporate anti rotation features for carrying torsional loads.
• The center to center spacing ofshafts372, labeled373 inFIG. 22, can be selected to reduce cocking or misalignment ofplate342 and to accommodate the movement ofprobe assembly438 in the X direction. In one embodiment, the spacing373 is at least about 6 inches, more particularly at least about 10 inches, and still more particularly at least about 12 inches. The center to center spacing ofshafts382 can be the same as or different than the spacing ofshafts372, and inFIG. 22 is shown to be greater than the spacing ofshafts372.
• Still referring toFIG. 22, theprobe assembly438 is supported on theprobe support plate352 so that the probe assembly can move in the X and the Z direction relative to theplate352. The probe assembly can be releasably attached to probemount320. The probe mount, in turn can be supported by a bushing or other bearing device to permit sliding of theprobe mount320 on ashaft392 for translation of theprobe mount320 andprobe assembly438 in the X direction. A locking mechanism (not shown)) can be used to releasably fix the mount320 (and so probe assembly438) at a desired X direction location along theshaft392.
• Shaft392 can be supported to be movable in the Z direction relative toplate352. InFIG. 22,shaft392 has its opposing ends supported in support blocks393. Support blocks393 can include bushings or other bearing devices to provide sliding of theblocks393 in the Z direction on two generallyparallel rails396.Rails396 are fixed to support plate352 (onerail396 associated with eachside portion353 inFIG. 22), and rails396 extend along their lengths in the Z direction. Accordingly, blocks393 (and so shaft392) can be positioned alongrails396 to position theprobe assembly438 in a desired Z direction location. A locking mechanism (not shown) can be associated with each support block393 to lock the shaft392 (and so probe assembly438) in a desired Z direction location.
• FIG. 23 provides an isometric schematic illustration of another alternative embodiment of afixture mechanism516 according to the present invention. Thefixture mechanism516 can include abase518, a movablebreast compression plate542 having parallel slots538 (through whichneedle point640 may pass), and aprobe support plate552 for supporting aprobe assembly638.FIG. 23 also illustrates a medialbreast compression plate522 which is positioned in one of a series of opposingslots526 formed in thebase518. The Y direction position of theplate522 relative to the frame can be varied in discrete intervals by positioning theplate522 in different pairs of opposingslots526.
• Theprobe support plate552 inFIG. 23 is supported on two generally parallel slide support rails572.Support plate552 is slidable onrails572 relative to the base518 in the Y direction. Support rails572 can be joined tobase518 along substantially their entire length, as shown inFIG. 23, to minimize cantilever loads and resulting positioning error. InFIG. 23,breast compression plate542 is supported on the same slide rails572, and each of theplates542 and552 can be positioned along therails572 at desired Y direction locations along the rails. Locking mechanisms (not shown) can be used to releasably fix theplates542 and552 in desired Y direction positions along therails572. A biopsy probe assembly638 (including needle with distal tip640) is supported on theprobe support plate552 to move relative to theplate552 in the X and Z directions, as described more fully below.
• Still referring toFIG. 23,probe support plate552 can includeplate side portions553 which are laterally spaced apart in the X direction. Abottom plate portion555 and atop bridge557 extend between theside portions553 and together with theside portions553 define an opening in thesupport plate552 through which a portion of theprobe assembly638 can extend.Bosses554 on eachplate portion553 can include bushings or other suitable bearing devices for sliding support ofplate552 onrails572.
• The movablebreast compression plate542 can includeplate side portions543 which are laterally spaced apart in the X direction. Theplate542 can include abridge547 and ribs which extend laterally between theside portions543 to provideslots538. Alternatively, the slots can be provided by a separate insert that is attached toplate542. InFIG. 23, aninsert642 is shown which includesribs649. Theinsert642 can slide into aslot549 formed throughbridge547, and theinsert642 can engage opposingside slots550 in theplate side portions543.Plates542 can includebosses544 extending laterally outwardly fromside portions543.Bosses544 can include bushings for supporting theplate542 for sliding onrails572.
• Rails572 can have splines, non circular cross sections, or otherwise incorporate anti rotation features. The center to center spacing ofrails572 can be selected to prevent cocking ofplate542 and552 on rails. In one embodiment, the spacing is at least about 6 inches, more particularly at least about 10 inches, and still more particularly at least about 12 inches.
• Still referring toFIG. 23, theprobe assembly638 can be releasably attached to aprobe mount520, such as by a spring loaded mechanism.Probe mount520 is supported on theprobe support plate552 so that the probe mount and probe assembly can move in the X and the Z direction relative to theplate552. Theprobe mount520 can be supported by a bearing on one or more shafts592 (two shafts shown inFIG. 23) for translation in the X direction. A locking mechanism (not shown) can be used to releasably fix theprobe mount520 at a desired X direction location along theshafts592.
• Theshafts592 can be supported to be movable in the Z direction relative toplate552. InFIG. 23,shafts592 have opposing ends supported in support blocks593. Support blocks593 can include bushings or other suitable bearing surfaces for sliding generallyparallel rails596.Rails596 are fixed to support plate552 (onerail596 associated with eachside portion553 inFIG. 23), and rails596 extend along their lengths in the Z direction. Accordingly,shaft592 can be positioned alongrails596 to position theprobe mount520 andprobe assembly638 in a desired Z direction location. A locking mechanism (not shown) can be associated with each support block593 to lock the shafts592 (and so probe assembly638) in a desired Z direction location.
• One or more fiducial markers can be attached to one or both of theplates542 and552 to present an artifact which is detectable in a magnetic resonance image. InFIG. 23 afiducial marker700 is shown positioned onbreast compression plate542. If desired, position encoders can be associated with each axis of motion, and the output from the encoders can be transmitted to a receiving source, such as a computer control and/or a visual readout display (e.g. an LED display). Position encoding can be accomplished using any suitable encoding means, including without limitation mechanical, optical, laser, or magnetic encoding means. A suitable encoder is an EM1 Optical Incremental encoder Module available from US Digital of Vancouver, Wash., USA. A position encoder can be associated with each ofplates542 and552 to identify the Y position of the plates' position along rails572. A position encoder can be associated with one or both ofblocks593 to identify the position of the blocks in the Z direction along rails596. A position encoder can be associated with theprobe mount520 to identify the position of themount520 in the X direction alongshafts592. One portion of the encoder system (such as a linear strip with indicia lines) can be attached or otherwise associated with a shaft or rail (e.g. rails572), and another portion of the encoder system (such as the sensor read head) can be attached to or otherwise associated with a part moving with respect to the shaft or rail (e.g. blocks593). The position information from the encoders can be used to determine, transmit, and/or visually display the X, Y, and Z position of the probe assembly (including needle tip640).
• InFIG. 23,rails572 provide a first pair of generally parallel, elongated sliding supports oriented in a first direction (Y), and rails596 provide a second pair of generally parallel, elongated sliding supports oriented in a second direction (Z) perpendicular to the first direction. Biopsyprobe support plate552 is adapted to support thebiopsy probe638 in a position that is everywhere between the two parallel rail supports572 (when viewed along the Z axis) and between the two rail parallel supports596 (when viewed along the Y axis), and withbiopsy probe638 being supported onprobe mount520 for sliding movement along a third direction (X) perpendicular to the first and second directions. Positioning the support rails572 and596, one each on each side ofprobe assembly638, so that the probe assembly is between each pair of generally parallel supports, can be helpful in minimizing probe misalignment and positioning inaccuracy.
• In using the apparatus ofFIG. 23, the patient's breast can be immobilized in the localization mechanism by advancing the lateral compression plate along the Y-axis. With the breast relatively immobilized, the patient is moved into the MRI magnet bore. An MRI scan of the breast is performed to locate suspicious tissue with reference to a fiduciary marker located on the localization mechanism. For a closed MRI magnet bore, the patient is then removed from the magnet bore (not necessary for an open bore). By scrolling through slice images of the breast, the MRI system allows the clinician to place a cursor on the suspicious tissue defining the coordinates of that point in space. Likewise, the clinician can also select the slice image that contains the fiducial marker and place a second cursor on it defining its coordinates. By comparing the two sets of coordinates, the relative position between the fiducial marker and the suspicious tissue can be calculated. Theprobe assembly638 can then be mounted onprobe mount520 on the localization mechanism. Using the X-Y-Z positioning capabilities of the localization mechanism, positioning guides on the localization mechanism are positioned at the fiducial marker and the X-Y-Z positions are zeroed-out to set the reference point. Theprobe assembly mount520 is then moved alongshafts592 in the X-axis direction the calculated relative distance and its position along the X-axis is fixed with the locking mechanism. Theprobe assembly mount520 is then moved in the Z direction by slidingblocks593/shafts592 onrails596 the calculated relative distance and its position along the Z-axis is fixed. Lastly, the probeassembly needle tip640 is inserted into the breast by advancing theprobe support plate552 along the Y-axis onrails572 the calculated relative distance to the predetermined biopsy site and its position is fixed along the Y-axis. The actual biopsy is then performed.
• FIG. 24 provides an isometric schematic illustration of a biopsy probe assembly (designated938) and a probe mount (designated820) incorporating a spring loaded “ball detent” mechanism for use in releasably attaching the probe assembly to the probe mount. InFIG. 24,probe mount820 is shown supported for sliding motion in the X direction on a shaft support designated892.Shaft892 can include splines (not shown) or otherwise have a non-circular cross-section.Biopsy probe assembly938 inFIG. 24 includes anengagement tang980 which extends vertically downward from the body of thebiopsy probe assembly938.Engagement tang980 includes oppositely facinggrooves984 machined or otherwise formed in opposite side faces982 oftang980.
• Probe mount820 includes anopening824 in a top surface of themount820 sized for receiving theengagement tang980. Opening824 can extend through the fully thickness ofmount820, or extend partially throughmount820. A pair of spring loadedball assemblies830 can be disposed in cylindrically shaped holes828 extending from opposite side surfaces ofmount820, the holes828 communicating withopening824. The spring loadedball assemblies830 can include: aball832 sized and shaped to engage agroove984 intang980; a biasing element, such as aspring834 for urgingball832 into engagement withgroove984; and aplug836 or other suitable mechanism for securing the ball and spring inprobe mount820. Suitable spring and ball assemblies can be purchased commercially. A user can, with a single hand, grasp theprobe assembly938 and engage the probe assembly with theprobe mount820 by pushing thetang980 downward into theopening824 until theballs832 of the mount engage thegrooves984 of the tang. The biasing force provided by thesprings834 assist in holding thebiopsy probe assembly938 in a fixed position with respect to theprobe mount820, and can reduce clearances that otherwise could result in positioning errors. The user can disengage theprobe assembly938 from theprobe mount820 with a single hand by pulling upwardly on theprobe assembly938 with sufficient force to overcome the spring force of the spring loaded ball assemblies. It will be understood that while a particular ball detent mechanism is shown for use inFIG. 24, other suitable release mechanisms may be substituted for releasably coupling the biopsy probe assembly to the biopsy probe mount.
• FIG. 25 is an isometric cut-away illustration of a threepiece clamp1376 useful in the present invention.Clamp1376 includes ahousing body1410, which can include a generally cylindrical throughbore1420 for receiving a bushing or other bearing member, such as abushing374, and a shaft, such asshaft372.Body1410 can also include a radially extendingassembly access aperture1424 which can communicate withbore1420 through a hole inbushing374.Clamp1376 also includes atoggle lever1440, aclamp actuation rod1450, apin1454 extending through a hole inrod1450 and through a clevis inlever1440 to pivotably connectlever1440 torod1450. Thepin1454 passes throughrod1450 near a top end ofrod1450, and a shaft engaging member, such aspad1460 is attached to an opposite second end ofrod1450. Thepad1460 can extend through an cylindrically shaped whole in bearing374. Thepad1460 can have a bottom surface shaped to accommodate a diameter of shaft372 (e.g. a shape generated by the surface of intersection of two perpendicular cylinders), and thepad1460 can be made a relatively soft, deformable material, such as rubber, a rubber like material, a deformable polymer, or other suitable material useful in frictionally engaging a shaft (e.g. shaft372). A biasing member, such as acoil spring1470 can be disposed in arecess1426 inhousing body1410. Coil spring can be positioned aroundrod1450 and can urgepad1460 downward into engagement withshaft372 when thelever1440 is in the horizontal position shown inFIG. 25. This first horizontal position oflever1440 corresponds to a shaft lock position. Thelever1440 can be rotated as indicated by arrowhead1498) to a second position where the lever is generally vertically upright (seeFIG. 26), such that rotation of thelever1440 raisespin1454 vertically, and so raisespad1460 up out of engagement withshaft372 to unlockshaft372.Lever1440 has asurface1442 which abuts against a top surface ofhousing1410 to maintainlever1440 in the upright second position oncelever1440 has been rotated (counter-clockwise inFIG. 25) to that position.Surface1442 can be spaced a distance from theaxis1454 so that whenlever1440 is rotated andsurface1442 is positioned to abut thehousing1410, thepin1454 is raised with respect to the housing, thereby raisingrod1450 andpad1460 against the biasing force ofspring1470. A third lever position corresponds to applying a downward pressing force onlever1440, in a direction shown byarrowhead1499. Pressing downward onlever1440 causeslever1440 to rock or pivot about asurface1412 onhousing1410, thereby raisingpin1454 androd1450 to liftpad1460 out of engagement withshaft372.
• FIGS. 26 and 27 are perspective illustrations showing use of the threeposition clamp1376 with thefixture assembly316 shown inFIG. 22. InFIG. 26, thefixture assembly316 is shown prior to attaching the biopsy probe assembly to probemount320.FIG. 26 shows clamps1376B in a locked (first) position and clamps1376A in an unlocked (second) position. Withclamps1376B in the locked position,compression plate342 and biopsyprobe support plate352 can be pushed together toward breast tissue (not shown) to compress the breast. InFIG. 26,upright levers1440 ofclamps1376A extend above (along Z direction) a lower portion of theside portions353 ofplate352.
• Once thebeast compression plate342 is in position, compressing tissue, it is desirable to lock the position ofplate342 and then moveplate352 back, away fromplate342 along the Y axis so that a biopsy probe device can be attached to probemount320.FIG. 27shows locking clamps1376B withlevers1440 in an unlocked (second) position so thatshaft382 and plate352 (to whichshaft382 is attached) can slide along the Y axis away fromcompression plate342.FIG. 27 also illustrates how movement ofplate352 relative to plate342 automatically lockscompression plate342 relative to shaft372 (and so fixesplate342 against breast tissue). InFIG. 27, movement ofplate352 relative to plate342 causesplate side portion353 to engageupstanding levers1440 locking clamps1376A, forcing rotation oflevers1440 to the locked (first) position, and thereby locking the Y position ofplate342 onshafts372. Accordingly, even if the physician or other user of the device forgets to lock the Y position of the compression plate prior to loading the biopsy device, the fixture ofFIG. 27 will automatically lock the position of the compression plate upon retraction of the biopsyprobe support plate352. Once theplate352 has been moved back along the Y axis relative to thecompression plate342, thebiopsy probe assembly438 can be attached to theprobe mount320.
• While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. For example, although alocalization mechanism316/516 is depicted that laterally compresses a downward hanging breast, aspects of the present invention are applicable to other orientations of localization/fixturing and imaging. Additionally, while twoshafts372/572 are shown inFIGS. 22 and 23, it may be desirable in other embodiments to have a single shaft372 (or572), such as a shaft mounted to the side of, or centered with respect to,plates342 and352.
• As an additional example, although MRI is discussed herein as the imaging modality for stereotopically guiding the core biopsy, the invention may apply to other imaging modes.
• As a further example, although a Cartesian XYZ positioning approach is disclosed herein, a polar or spherical positioning approach may be implemented in whole or in part so that the detachable probe assembly enters at a predefined angle.
• As another example, although a prone breast compression device is depicted, application of the present invention may be used in medical devices oriented in other manners, to include standing, lying on one side, or supine. In addition, aspects of the present invention may be applicable to positioning a biopsy probe through a medial compression plate, or a top and bottom compression plate pair, instead of a lateral compression plate. Furthermore, aspects of the present invention are applicable to other diagnostic imaging modalities currently used or that become available in the future. In addition, aspects of the present invention would have application to diagnostic guided biopsy procedures on other portions of the body, as well as to positioning a probe for utilizing other diagnostic and treatment devices in a minimally invasive manner.

Claims (5)

1-15. (canceled)

16. A biopsy device positioning assembly comprising;

a breast compression member positionable along a Z direction to provide compression of a patient' breast, the breast compression member having a plurality of openings therethrough;

a mount adapted for releasably engaging a biopsy device;

an apparatus for supporting the mount, the apparatus providing adjustable positioning of the mount in an X direction and a Y direction relative to the breast compression member, wherein the X and Y directions are generally perpendicular to one another and the Z direction, and wherein the mount is supported to be advanced and retracted in the Z direction to provide positioning of a portion of a biopsy device supported by the mount through one of the plurality of openings in the breast compression member.

17. The assembly ofclaim 16 further comprising a locking member operable to releasably lock the mount in a desired position with respect to the breast compression member.

18. An apparatus for use in positioning a biopsy device, comprising:

a compression member having a plurality of openings therethrough;

a positioning assembly comprising:

a first support rail extending in an X direction;

a second support rail extending in a Y direction generally perpendicular to the X direction;

a third support rail extending in a Z direction generally perpendicular to the X direction and the Y direction; and

a mount for releasably engaging a biopsy device, the mount supported on the positioning assembly and positionable with respect to the compression member in each of the X, Y, and Z directions.

19. A apparatus for use in biopsy procedures, the apparatus comprising:

a compression member adjustable along a first direction for providing tissue compression;

at least two generally parallel, spaced apart elongated supports extending in a second direction generally perpendicular to the first direction, the spaced apart elongated supports having fixed center to center spacing; and

a biopsy probe support slidably supported on an elongated support extending in a third direction perpendicular to the first and second directions;

wherein the biopsy probe support is adapted to releasably engage a biopsy device.

Images