U.S. patent application number 12/255027 was filed with the patent office on 2009-06-18 for localization mechanism for an mri compatible biopsy device.
Invention is credited to John C. Tinsley, III, Eric W. Thompson, Mark Tsonton.
Application Number | 20090156961 12/255027 |
Document ID | / |
Family ID | 32042956 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090156961 |
Kind Code |
A1 |
Tsonton; Mark ; et
al. |
June 18, 2009 |
LOCALIZATION MECHANISM FOR AN MRI COMPATIBLE BIOPSY DEVICE
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.
Inventors: |
Tsonton; Mark; (Loveland,
OH) ; C. Tinsley, III; John; (Cincinnati, OH)
; Thompson; Eric W.; (Pleasant Plain, OH) |
Correspondence
Address: |
PHILIP S. JOHNSON;JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
32042956 |
Appl. No.: |
12/255027 |
Filed: |
October 21, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10273445 |
Oct 18, 2002 |
7438692 |
|
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12255027 |
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Current U.S.
Class: |
600/562 |
Current CPC
Class: |
A61B 2090/3954 20160201;
A61B 2017/00477 20130101; A61B 10/0275 20130101; A61B 2017/3411
20130101; A61B 2017/00398 20130101; A61B 2090/3933 20160201; A61B
90/17 20160201; A61B 2017/347 20130101; A61B 90/11 20160201; A61B
2017/008 20130101; A61B 17/3403 20130101 |
Class at
Publication: |
600/562 |
International
Class: |
A61B 10/00 20060101
A61B010/00 |
Claims
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 of claim 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.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] 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
[0002] 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
[0003] 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.
[0004] 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.
[0005] 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.TM., 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.TM. 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.TM. 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.TM. is desirable
because the handpiece on the MAMMOTOME.TM. 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] Consequently, a significant need exists for a device for
accurately positioning an MRI-assisted biopsy device.
BRIEF SUMMARY OF THE INVENTION
[0019] The invention provides an apparatus useful for positioning a
biopsy probe.
[0020] 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.
[0021] 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).
[0022] 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
[0023] 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.
[0024] 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.
[0025] 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.
[0026] FIG. 4 is an isometric view of the biopsy instrument
disassembled into a biopsy instrument handle, probe housing, and
probe.
[0027] FIG. 4A is a frontal isometric detail view of an alternative
needle tip of a biopsy instrument.
[0028] FIG. 5 is an exploded isometric view of a biopsy instrument
handle.
[0029] FIG. 6 is an exploded isometric view of the probe of the
biopsy instrument of FIG. 4.
[0030] FIG. 7 is a transverse cross section of the probe of the
biopsy instrument of FIG. 4 along lines 7-7.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] FIG. 11 is an isometric view of the biopsy instrument with
the handle portion disconnected from a tower/bracket localization
fixture and probe assembly.
[0035] FIG. 12 is an isometric view of the biopsy instrument
mounted to the tower/bracket localization fixture of FIG. 11.
[0036] FIG. 13 is an exploded isometric view of the tower/bracket
localization version of the localization fixture and probe assembly
of the biopsy instrument.
[0037] 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.
[0038] 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.
[0039] FIG. 16 is an isometric view of the biopsy instrument
mounted to a dual tower localization fixture.
[0040] 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.
[0041] 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.
[0042] FIG. 19 is a sequence of clinical operations for using the
detachable MRI-guided biopsy instrument of FIG. 1 in both open and
closed MRI machines.
[0043] FIG. 20 is an isometric view of a tip protector mounted onto
a needle tip of the detachable probe assembly of FIG. 11.
[0044] FIG. 21 is an isometric detail view of the trip protector of
FIG. 20.
[0045] FIG. 22 is an isometric view of one embodiment of a
localization mechanism according to the present invention.
[0046] FIG. 23 is an isometric view of an alternative embodiment of
a localization mechanism according to the present invention.
[0047] FIG. 24 is an isometric view of a biopsy mount employing a
ball detent mechanism for releasably engaging a biopsy probe
assembly.
[0048] FIG. 25 is a cut away isometric view of a three position
locking clamp.
[0049] FIG. 26 is an isometric illustration of the localization
mechanism of FIG. 22 illustrating sliding a compression plate along
a Y axis for compressing tissue.
[0050] FIG. 27 is perspective illustration of the localization
mechanism of FIG. 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
[0051] 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.
[0052] FIG. 1 depicts a core biopsy instrument system 10 that is
vacuum assisted, detachable, and compatible with use in a Magnetic
Resonance Imaging (MRI) machine, such as the depicted closed MRI
machine 12. In the illustrative embodiment, the core biopsy
instrument system 10 includes an MRI-compatible biopsy tool 14 that
is selectably attached to a localization mechanism or fixture 16 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 the
biopsy tool 14 and provides mechanical and vacuum power to the
biopsy tool 14 via power cord 18.
[0053] With reference to FIGS. 1-2, a patient 20 is lying prone
upon a patient support table 22, depicted in FIG. 1 as removed from
a magnet bore 24 of the MRI machine 12. The patient's chest rests
upon a top surface 26 of a chest support 28, the top surface 24
having openings 30, 32 for allowing the patient's breasts to hang
downward for imaging and treatment. With particular reference to
FIG. 2, the right opening 30 is depicted with the localizer fixture
16 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 the
opening 30 to detect radio frequency (RF) signals emanated from
breast tissue induced by a strong magnetic field from the MRI bore
24. The chest support 28, localization fixture 16, and antennas are
generally termed a breast coil 34.
[0054] The biopsy tool 14 includes a biopsy handle 36 that
attachable to a probe assembly 38. The localization fixture 16
accurately positions the probe assembly 38 for stereotactic
MRI-guided biopsy procedures for a specific biopsy site location
for a distal tip 40 of the probe assembly 38. This location is
identified by an X-axis coordinate that is horizontal and
longitudinal with respect to the patient (depicted as right to left
in FIGS. 1-2). A Z-axis is defined as the vertical height, with the
X and Z axis orthogonally defined on a lateral compression plate 42
of the localization fixture 16, the lateral compression plate 42
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 the FIGS. 1-2. A probe assembly mounting device 44 connects
to a probe housing 46 of the biopsy tool 14.
[0055] The mounting device 44 includes alignment positioning guides
(described in more detail below) to orient the probe housing 46,
and hence the probe assembly 38, to the desired X-Y-Z coordinate.
For instance, a depth slide 48 allows mounting of the probe
assembly 38 with the distal tip 40 extends outside of the opening
30 and lateral compression plate 42. Thereafter, the probe assembly
38 is guided along the Y-axis by the depth slide 48 while
maintaining the selected X-Z-axes coordinates. In addition, the
mounting device 44 advantageously supports the biopsy handle 36
when attached to the probe assembly 38 as depicted in FIG. 2 to
maintain the angle of insertion of the probe assembly 38. The probe
housing 46 provides access to the interior of the probe assembly 38
via a vacuum lumen access conduit 50 for draining fluids, inserting
fluids such as anesthetics.
[0056] FIG. 3 depicts the core biopsy instrument system 10 with the
biopsy handle 36 removed and the depth slide 48 moved inward to
allow insertion of the patient support table 22 into the narrow
confines of the MRI magnet bore 24. Moreover, the surgeon may take
full advantage of the stereotactic coordinates provided by the MRI
machine 12, even if using a closed magnetic bore 24. In particular,
the stereotactic derived coordinates may be used even if not
actively imaging the probe assembly 38 during insertion. The
localization fixture 16 enables the surgeon to manually insert the
probe assembly 38 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 the probe assembly 38
maintained in the correct location after insertion, the probe
assembly 38 provides access for other diagnostic and therapeutic
tools and fluid treatments.
[0057] Alternatively or in addition, a Y-axis adjustment mechanism
may be incorporated into the localization fixture 16 to provide
mechanical advantage, thereby achieving a controlled and deliberate
insertion of the probe assembly 38. Moreover, the Y-axis adjustment
mechanism may incorporate a frictional, ratcheting or locking
feature to prevent inadvertent movement of the probe assembly 38
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 probe assembly mounting device 150
and the localizer support frame 126.
[0058] FIG. 4 depicts the biopsy tool 14 with the biopsy handle 36
depicted as readily attached to the probe housing 46, which in turn
is readily attached to the probe assembly 38. The probe assembly 38
includes a male cylindrical mating portion 52 presenting a central
cutter opening 54 on a proximal end that is aligned with the
longitudinal length of a cutter lumen 56 of an elongated needle 58.
The cutter lumen 56 communicates with a sample port 60 laterally
presented near a needle tip 62 at the distal end of the needle 58.
The needle tip 62 is for penetrating the soft tissue of a surgical
patient. The needle tip 62 is sharpened and is preferably made from
an MRI compatible resin such as ULTEM or VECTRA. In the
illustrative embodiment, the needle tip 62 is a three-sided
pyramidal shaped point, although the needle tip 62 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.
[0059] FIG. 4A depicts a needle tip 62' having a conical shape with
a distally presented X-shaped slot 63 for receiving a pointed,
sharpened blade 65 that reduces the probe insertion force into
tissue. The blade 65 could be made of titanium, stainless steel,
nitinol, aluminum, Elgiloy, ceramic, etc. It will be appreciated
that other shapes of sharpened blade 65 may be used, such as a
single pointed surface in a distally presented single slot rather
than two perpedicularly crossed, pointed surfaces as depicted.
[0060] It will be appreciated that a cutter element or an obturator
stylet is advanced inside the cutter lumen 56 to block the sample
port 60 during insertion. Once the needle 58 is positioned, the
sample port 60 is exposed to allow tissue to enter. In particular,
a vacuum may be presented to a "sample bowl" inside the cutter
lumen 56 near the sample port 60 by applying vacuum power through a
vacuum chamber lumen 64 that communicates along the longitudinal
length of the needle 58 to the male cylindrical mating portion 52.
In particular, a series of small holes allow gas and fluid to enter
the vacuum chamber lumen 64 from the sample port 60 but prevent
tissue samples from entering.
[0061] Annular rings 66 about the cylindrical mating portion 52
grip and seal to an interior of a female cylindrical mating portion
68 on the probe housing 46. Between annular rings, a proximal
vacuum port (not shown in FIG. 4) communicates with a vacuum
passage (not shown) in the probe housing 46. The engagement between
the mating portions 52, 68 advantageously allows rotation of the
needle 58 with a thumb wheel 70 annularly presented near the
proximal end of the needle 58. The radial opening presented by the
annual rings 66 maintains communication between the vacuum passage
in the probe housing 46 and the vacuum chamber lumen 64 regardless
of radial orientation of the needle 58. Thereby, the sample port 60
may be presented to tissue at any and all radial positions about
the distal end of the needle 58. With the assistance of vacuum, a
large volume of tissue may be selectably drawn into the sample bowl
for biopsy sampling.
[0062] The probe housing 46 includes laterally presented attachment
prongs 72 for mounting to the localization fixture 16. In addition,
the probe housing 46 presents a proximally directed cuboidal
engagement member 74 with longitudinally aligned vertical and
horizontal grooves 76 for flanges 78 from the biopsy handle 36. The
probe housing 46 also receives hooked locking tabs 80, 82 on the
distal engaging end of the biopsy handle 36 for selective locking
and unlocking under the influence of a pair of opposing depression
grips 84, 86 attached to respective tabs 80, 82. The biopsy handle
36 includes a sample window 88 for extracting any tissue sample
withdrawn from the cutter lumen 52 under the influence of a vacuum
passing through the cutter, as described in more detail below.
[0063] FIG. 5 depicts a disassembled biopsy handle 36 that contains
the means for translating and rotating a cutter 90 within the
cutter lumen 56. It will be appreciated that two rotating
mechanical power sources are presented to the proximal end of the
biopsy handle 36 through the power cord 18 to provide the
independent translation and rotation motions. These two rotating
mechanical power sources enter through a cord opening 92 defined
between a removable shell 94 and a bottom shell 96, the two held
together by screws. The removable shell 94 is removed when
assembling a power cord 18 to the handle 36. A lower gear housing
98 is supported upon the bottom shell 96 and cooperates with a top
shell 100 to constrain movement of an elongate drive screw 102, an
elongate axial screw 104 and cutter carriage 106. In particular,
both screws 102, 104 are allowed to rotate, positioned parallel to
one another and the longitudinal axis of the cutter lumen 56. Each
screw 102, 104 is driven by a respective power source from the
power cord 18. The drive screw 102 passes through the carriage 106
and interacts with corresponding ridges therein to impart a
longitudinal translation corresponding to the direction and rate of
rotation of the drive screw 102.
[0064] 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 handle 36 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 the cutter 90 to directly control its movement.
[0065] The cutter 90 is an elongate tube with a sharpened distal
end for cutting tissue presented within the distal end of the
cutter lumen 56. The proximal end of the cutter 90 includes a
cutter gear 108 that is exposed through a gear window 110 of the
carriage 106 to mesh with the axial screw 104 for axial rotation of
the cutter 90. A tissue remover 111 is a tube that is fixedly
aligned with the longitudinal axis to enter the proximal end of the
cutter 90. The tissue remover 111 extends up to the sample window
88 and has a vacuum selectably applied to it by the control module.
Thus, when the cutter 90 is retracted, vacuum from the tissue
remover 111 draws the sample to the distal end of the cutter 90 for
retraction to the sample window 88, whereupon the sample encounter
the tissue remover 111 and is dislodged for exiting the biopsy tool
14.
[0066] The carriage 106 includes distally projected guides 112, 114
that advantageously take-out slack between biopsy handle 36 and the
probe housing 46, as well as providing indicia to the surgeon as to
the depth of translation of the cutter 90. Taking out slack between
the assembled parts of the handle 36 and housing 46 advantageously
minimizes the deadzone length of the distal end of the needle 58.
The cutter 90 should completely translate past the sample port 60
in order to reliably cut a sample. To ensure a full cut, the cutter
90 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 the cutter lumen 56 distal to the sample port 60 to accommodate
the over-travel. Thereby, the needle tip 62 must be advanced
farther than desirable in some instances, preventing placement of
the sample port 60 near critical body tissues. At or near full
travel, the guides 112, 114 contact the probe housing 46, causing
movement of the housing 46 to its maximum, distal position. Thus,
critical dimensioning to minimize tolerance build-up is
simplified.
[0067] FIG. 5 also depicts a brace 116 and brace arm 118 that are
employed in one version of the localization fixture 16 to support
the weight and maintain the alignment of the handle 36. Thereby,
flexure of the assembly is avoided that may place a load on the
probe assembly 38, and thus unwanted movement of the needle 58 from
the desired biopsy site location.
[0068] FIGS. 6-7 depict the needle 58 of FIG. 4 and described more
fully in the aforementioned application Ser. No. 10/021,680,
entitled "AN MRI COMPATIBLE SURGICAL BIOPSY DEVICE". In particular,
elongated needle 58 is formed from a left body member 120 and a
right body member 121 on either side of the longitudinal axis. The
edges of the halves 120 and 121 are gated for easy part filling,
and the edges are stepped with ridges that allow the two halves 120
and 121 to attach together with ease. The two halves 120, 121 are
adhesively attached to one another. A cutter tube liner 122 is
inserted between the two halves 120, 121 to provide a smooth
surface for the cutter 90, especially by preventing adhesive from
entering the cutter lumen 56 during assembly.
[0069] FIG. 8 shows an enlarged view of the engagement of the
handle 36 to the probe housing 46, with the advanced cutter 90
evident through the window 88. In addition, the guides 112, 114 are
advanced almost into contact with the probe housing 46, indicating
that the distal end of the cutter 90 is approaching its furthest
translation. The guides 112, 114 contact the probe housing 90 when
at or near this extreme to take-out any tolerance. Indicia on the
side of the guides 112, 114 may be referenced by the surgeon to
determine the position of the cutter. Also shown in more detail is
hooked locking tabs 80, 82 entering the probe housing 46, the thumb
wheel 70 used to rotate the needle 80, and the vacuum lumen access
conduit 50 used to evacuate or otherwise access the vacuum lumen
64.
[0070] FIGS. 8-10 show that each grip 84, 86 includes a respective
inwardly projecting member 124, 125 that contact the guides 112,
114 when the cutter 90 is distally advanced, thereby preventing
removal of the handle 36. In FIG. 9, the cutter 90 is retracted,
allowed the depression of the grips 84, 86, unlocking the hooked
locking tabs 80, 82 from the probe housing 46. In FIG. 10, cutter
carriage 106 is advanced, the guides 112, 114 are contacting the
probe housing 46, thereby removing any longitudinal gap between the
hooked locking tabs 80, 86 and the probe housing 46.
[0071] FIGS. 11-14 depicts a localization fixture 16 that includes
means for accurately positioning the probe assembly 38 and
supporting the biopsy handle 36. In particular, a localizer support
frame 126 is formed from the compression plate 42 in a hinged,
orthogonal relation to a horizontal slide plate 128, both laterally
attached to one another by gussets 130, 132. Rods 134, 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 of slots
138, in the compression plate 42 are provided to obtain access to a
desired biopsy site location while providing enough remaining
structure in the compression plate 42 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 the compression plate 42 may be permeable
to allow an aperture to be formed as needed.
[0072] The desired biopsy site location is stereotactically
determined during an MRI scan with reference to a fiducial marker
140 that presents a small artifact. The fiducial marker 140 is
contained within a fiducial marker holder 142 that may be placed at
a convenient location on the compression plate 42, accurately
placed with reference to indents spaced along the slots 138.
Alternatively, the fiducial marker may be embedded or affixed to
the compression plate 42.
[0073] The localizer support frame 126 defines and provides the
guide for positioning the probe assembly 38. The X-Y-Z axes are
defined with regard to the slots 138 and compression plate 42. In
particular, the vertical dimension, or Z-axis, and horizontal
dimension, or X-axis, are defined by the surface of the compression
plate 42. The depth dimension, or Y-axis, is defined as distance
away from the plane of the compression plate 42. The horizontal
slide plate 128 includes laterally aligned front and back rails
144, 146 for setting the X-axis coordinate. Horizontal indicia 148
along the front rail 144 give the surgeon an accurate measurement
of the position of a probe assembly mounting device 150.
[0074] A first version of the mounting device 150 is depicted that
uses a single vertical pedestal 152 to position and support the
probe assembly 38. In addition, the biopsy handle 36 is supported
by a brace 116 connected to the proximal underside of the handle 36
to a handle support rod 156 that is slid through a rod hole 158 to
the corresponding side of the vertical pedestal 152. The
appropriate height for the brace 116 is determined by selecting one
of a range of slots arrayed along the underside of the handle,
thereby pivoting the brace 116 about a brace arm 118 whose first
end slidably pivots within a slot 162 in the middle of the brace
116 and second end attaches to the distal end of the handle 36.
[0075] With the handle 36 detached from the probe assembly 38 as
depicted in FIG. 11, an obturator stylet 164 is slid into the
cutter lumen 56 to close the cutter port 88. The stylet 164 may
have radially-oriented through holes near its distal end to
maintain fluid communication between the vacuum lumen chamber 64
and cutter lumen 56. Alternatively, the stylet 164 may be partially
withdrawn, allowing the cutter port 88 to be in fluid communication
with the conduit 50
[0076] A slide 166 includes a grooved underside to horizontally
slide on rails 144, 146 of the slide plate 128. The slide 166 also
includes a central channel 168 oriented in the Y-axis depth
dimension to guide the pedestal 152 as it slides in the Y-axis
direction. Sufficient range of motion in depth is achieved with a
pivoting depth slide 170, aligned and pivotally attached to the
slide 166. With the pivoting depth slide 170 in its lowest,
horizontal position, the pedestal 152 may be slid outward
sufficiently for the probe assembly 38 to be out of the compression
plate 42. With the pedestal 152 distally slid onto the slide 166,
the pivoting depth slide 170 may be pivoted upward or otherwise
removed. Depth indicia 172 along the central channel 168 give the
surgeon an indication of the insertion depth of the probe assembly
38.
[0077] A vertical slide 174 slides on the pedestal 152 for vertical
positioning along the Z-axis, with a measurement provided by
vertical indicia 176 on the pedestal 152. Holes 178 on each lateral
side of the vertical slide 174 allow mounting of the probe housing
46 on either side by insertion of attachment probes 72.
[0078] FIGS. 15-16 depict a second version of the mounting device
150 that uses a second vertical pedestal 180 in lieu of a brace
assembly to support the handle 36. The probe housing 46 is also
depicted as attached to the opposite side of the first vertical
pedestal 152. A second vertical slide 181 of the second vertical
slide 180 advantages contacts the first vertical slide 174, as
shown in FIG. 16, so that setting the vertical height for both is
accomplished in one step. Each vertical slide 174, 181 moves in a
ratchet fashion against its respective vertical pedestal 152, 180,
and thus remains in position after being separated from one another
as shown in FIG. 15. Moreover, the close nesting of the two
vertical pedestals 174, 180 enhances the ability to minimize the
proximal displacement of the localization fixture 16 when used
within the close confines of a closed MRI magnetic bore 24. It will
be further appreciated that the second vertical slide 181 includes
a shaped area that engages the underside of the handle 36 in such a
way as to correctly align the handle 36 at the same X-axis
horizontal dimension as the probe assembly 38.
[0079] FIGS. 17-18 depict a third version of the mounting device
150 wherein the slide 166 and pedestal 152 are replaced with a
scissors table assembly 182 that includes a first slide 184 for
horizontal movement on the slide plate 128. A depth slide 186 is
nested within a top channel 188 of the first slide 182. With
particular reference to FIG. 18, a pair of scissors braces 190 are
extended when drawn together with a screw 192, thereby elevating
the depth slide 186 with respect to the first slide 184. It will be
appreciated that the third version of the mounting device 150
advantageously provides a level support for both the detachable
probe assembly 38 as well as the biopsy handle 36 without having to
perform two vertical adjustments, as well as not having to perform
two separate attachments for each of the handle 36 and probe
assembly 38.
[0080] FIG. 19 depicts a sequence of operations, or method 200, 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.
[0081] Prior to performing a clinical breast biopsy, the equipment
is initialized to ensure proper function. Thus, in block 202, 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 (block 204). 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 (block 206);
rotational drivetrain initialization is performed (block 208); and
vacuum system initialization is performed (block 210). If
initialization is not required, then blocks 206-210 are
bypassed.
[0082] Then, the patient's breast is immobilized in the
localization mechanism (block 212) and the patient is moved into
the MRI magnet bore (block 214). An MRI scan is performed to
stereotopically locate suspicious tissue with reference to a
movable fiduciary marker on the localization mechanism (block 216).
For a closed MRI magnet bore, the patient is then removed (block
218), which is not necessary for an open bore. Anesthesia is
administered prior to the minimally invasive vacuum assisted core
biopsy procedure (block 220). 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 (block 222).
[0083] Optionally, insertion may be enhanced by use of an insertion
tool installed through the probe assembly 38 (block 224). For
instance, an ultrasonic cutting tip, extender, and outer tube
assembly may be inserted through the probe assembly 38 through a
slot in the needle tip 62, or exiting from the sample port 60 to be
snapped onto the needle tip 62. This could be accomplished with a
housing on the ultrasonic device that is configured to snap onto
the needle 58, similarly to how a trocar obturator snaps onto the
trocar cannula. Then, the ultrasonic tip is energized prior to
insertion into the patient.
[0084] The probe assembly is mounted on the localization mechanism
(block 226) 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 (block 228), if not otherwise sealed by a
tool in block 224. The vacuum lumen may be similarly sealed (e.g.,
stopcock attached to vacuum lumen access conduit 50) 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 (block 230). Once in place, if an insertion
enhancement tool was installed in block 224, then this tool is
withdrawn through the cutter lumen of the probe assembly (block
232).
[0085] With the probe in place, various fluid transfers may
advantageously take place through the probe assembly (block 234).
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 (block 236). 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 (block 238). 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 (block 240).
[0086] 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 (block 244). If more samples at this biopsy site are
required for diagnostic or for treatment purposes (block 246), then
the thumb wheel is rotated to reorient the sample port to another
angle (block 248), and sample mode is performed again by returning
to block 244.
[0087] 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 (block 250). 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.
[0088] 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 (block 252) and the probe is
removed (block 254).
[0089] FIGS. 20-21 depict a tip protector 260 that advantageously
protects the needle tip 62 of the probe assembly 38 prior to
insertion into tissue and simplifies localization of the probe
assembly 38 in some instances. Furthermore, the tip protector 260
does not interfere with pre-clinical setup procedures (e.g.,
testing for vacuum leaks). In particular, the tip protector 260
includes an attachment member 262 with clips onto the needle 58
without obstructing the sample port 60. A distal portion of the tip
protector completely encompasses the needle tip 62 with a
protection member, depicted as a hemispheric disk 264, that may be
placed in contact with a patient's breast without discomfort. In
addition, in some applications the hemispheric disk 264 may be
comprised of or include an MRI artifact producing material, such as
those described above. Since the hemispheric disk 264 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.
[0090] With a fiducial marker integrated into the tip protector
260, 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 the tip protector 260 in place, the operator
would attach the probe assembly 38 onto the pedestal 152 and move
the probe assembly 38 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. The attachment member 262
accurately locates the hemispheric disk 264 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.
[0091] FIG. 22 provides an isometric schematic illustration of an
embodiment of a fixture mechanism 316 according to the present
invention. The fixture mechanism 316 can include a base 318, a
movable breast compression plate 342 having apertures for
accommodating a biopsy needle (apertures in the form of parallel
slots 338 in FIG. 22), and a probe support plate 352. The probe
support plate 352 can be supported to move independently of the
breast compression plate 342 in the Y direction. A biopsy probe
assembly 438 (including needle with distal tip 440) can be
supported on probe support plate 352 to move relative to the probe
support plate 352 in the X and Z directions, as described in more
detail below. The biopsy probe assembly 438 can be releasably
attached to a probe assembly mount 320, such as by a spring loaded
mechanism (e.g. ball detent) or other biasing mechanism for
reducing clearances between the assembly 438 and the mount 320 (in
order to improve positional accuracy of the probe). Probe assembly
mount 320 in turn can be supported on support plate 352 to permit
movement of mount 320 with respect to support plate 352, as
described more fully below.
[0092] Still referring to FIG. 22, probe support plate 352 can
include plate side portions 353 which are laterally spaced apart in
the X direction. A bottom plate portion 355 and a top bridge 357
extend between the side portions 353 and together with the side
portions 353 define an opening in the support plate 352 through
which a portion of the probe assembly 438 can extend.
[0093] Compression plate 342 is supported on slide shafts 372
(which can be rigidly attached to or otherwise fixed relative to
the base 318) to translate relative to the base 318 in the Y
direction. The Compression plate 342 can be supported by bushings
374A (or other suitable bearings) for permitting sliding of the
plate 342 on shafts 372. The bushings can be disposed in bosses 347
which extend from side portions 343. Bushings 374A can extend along
shafts 372 to also be disposed within a locking mechanism
associated with shaft 372, such as releasable clamp locking
mechanisms discussed below. Shafts 372 can include splines, a non
circular cross-section or have other anti-rotation features to
prevent rotation of the shaft with respect to the plate 342 and for
carrying torsional loads.
[0094] A locking mechanism 376A can be associated with each support
shaft 372 to releasably fix the position of the compression plate
342 in a desired Y location along the shafts 372. 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 the plate 342 at a desired
location along the shafts 372 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.
[0095] The movable breast compression plate 342 can include plate
side portions 343 which are laterally spaced apart in the X
direction. The plate 342 can include a bridge 347 and ribs 349
which extend laterally between the side portions 343 to provide
apertures (slots 338 in FIG. 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 to
plate 342.
[0096] The movable breast compression plate 342 engages two shafts
382 at bushings 374B. Bushings 374B are shown disposed in bosses
344. Bosses 344 extend laterally outwardly from each plate side
portion 343 of compression plate 342. Breast compression plate 342
can slide in the Y direction relative to shafts 382. Accordingly,
breast compression plate 342 is supported to slide relative to both
shafts 372 and shafts 382 in the Y direction. Shafts 382 are
generally parallel to, or collinear, with shafts 372, and shafts
382 have ends which can be fixed to probe support plate 352. In the
embodiment in FIG. 22, shafts 382 are cantilevered from bosses 354
which extend laterally outwardly from each plate side portion 353
of the support plate 352. Sliding movement of shafts 382 with
respect to plate 342 results in motion of plate 352 with respect to
plate 342 in the Y direction. A locking mechanisms 376B can be
associated with each shaft 382 to releasably fix breast compression
plate 342 with respect shaft 382 (and also with respect to plate
352) in the Y direction. Shafts 382 can have splines, non circular
cross sections, or otherwise incorporate anti rotation features for
carrying torsional loads.
[0097] The center to center spacing of shafts 372, labeled 373 in
FIG. 22, can be selected to reduce cocking or misalignment of plate
342 and to accommodate the movement of probe assembly 438 in the X
direction. In one embodiment, the spacing 373 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
of shafts 382 can be the same as or different than the spacing of
shafts 372, and in FIG. 22 is shown to be greater than the spacing
of shafts 372.
[0098] Still referring to FIG. 22, the probe assembly 438 is
supported on the probe support plate 352 so that the probe assembly
can move in the X and the Z direction relative to the plate 352.
The probe assembly can be releasably attached to probe mount 320.
The probe mount, in turn can be supported by a bushing or other
bearing device to permit sliding of the probe mount 320 on a shaft
392 for translation of the probe mount 320 and probe assembly 438
in the X direction. A locking mechanism (not shown)) can be used to
releasably fix the mount 320 (and so probe assembly 438) at a
desired X direction location along the shaft 392.
[0099] Shaft 392 can be supported to be movable in the Z direction
relative to plate 352. In FIG. 22, shaft 392 has its opposing ends
supported in support blocks 393. Support blocks 393 can include
bushings or other bearing devices to provide sliding of the blocks
393 in the Z direction on two generally parallel rails 396. Rails
396 are fixed to support plate 352 (one rail 396 associated with
each side portion 353 in FIG. 22), and rails 396 extend along their
lengths in the Z direction. Accordingly, blocks 393 (and so shaft
392) can be positioned along rails 396 to position the probe
assembly 438 in a desired Z direction location. A locking mechanism
(not shown) can be associated with each support block 393 to lock
the shaft 392 (and so probe assembly 438) in a desired Z direction
location.
[0100] FIG. 23 provides an isometric schematic illustration of
another alternative embodiment of a fixture mechanism 516 according
to the present invention. The fixture mechanism 516 can include a
base 518, a movable breast compression plate 542 having parallel
slots 538 (through which needle point 640 may pass), and a probe
support plate 552 for supporting a probe assembly 638. FIG. 23 also
illustrates a medial breast compression plate 522 which is
positioned in one of a series of opposing slots 526 formed in the
base 518. The Y direction position of the plate 522 relative to the
frame can be varied in discrete intervals by positioning the plate
522 in different pairs of opposing slots 526.
[0101] The probe support plate 552 in FIG. 23 is supported on two
generally parallel slide support rails 572. Support plate 552 is
slidable on rails 572 relative to the base 518 in the Y direction.
Support rails 572 can be joined to base 518 along substantially
their entire length, as shown in FIG. 23, to minimize cantilever
loads and resulting positioning error. In FIG. 23, breast
compression plate 542 is supported on the same slide rails 572, and
each of the plates 542 and 552 can be positioned along the rails
572 at desired Y direction locations along the rails. Locking
mechanisms (not shown) can be used to releasably fix the plates 542
and 552 in desired Y direction positions along the rails 572. A
biopsy probe assembly 638 (including needle with distal tip 640) is
supported on the probe support plate 552 to move relative to the
plate 552 in the X and Z directions, as described more fully
below.
[0102] Still referring to FIG. 23, probe support plate 552 can
include plate side portions 553 which are laterally spaced apart in
the X direction. A bottom plate portion 555 and a top bridge 557
extend between the side portions 553 and together with the side
portions 553 define an opening in the support plate 552 through
which a portion of the probe assembly 638 can extend. Bosses 554 on
each plate portion 553 can include bushings or other suitable
bearing devices for sliding support of plate 552 on rails 572.
[0103] The movable breast compression plate 542 can include plate
side portions 543 which are laterally spaced apart in the X
direction. The plate 542 can include a bridge 547 and ribs which
extend laterally between the side portions 543 to provide slots
538. Alternatively, the slots can be provided by a separate insert
that is attached to plate 542. In FIG. 23, an insert 642 is shown
which includes ribs 649. The insert 642 can slide into a slot 549
formed through bridge 547, and the insert 642 can engage opposing
side slots 550 in the plate side portions 543. Plates 542 can
include bosses 544 extending laterally outwardly from side portions
543. Bosses 544 can include bushings for supporting the plate 542
for sliding on rails 572.
[0104] Rails 572 can have splines, non circular cross sections, or
otherwise incorporate anti rotation features. The center to center
spacing of rails 572 can be selected to prevent cocking of plate
542 and 552 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.
[0105] Still referring to FIG. 23, the probe assembly 638 can be
releasably attached to a probe mount 520, such as by a spring
loaded mechanism. Probe mount 520 is supported on the probe support
plate 552 so that the probe mount and probe assembly can move in
the X and the Z direction relative to the plate 552. The probe
mount 520 can be supported by a bearing on one or more shafts 592
(two shafts shown in FIG. 23) for translation in the X direction. A
locking mechanism (not shown) can be used to releasably fix the
probe mount 520 at a desired X direction location along the shafts
592.
[0106] The shafts 592 can be supported to be movable in the Z
direction relative to plate 552. In FIG. 23, shafts 592 have
opposing ends supported in support blocks 593. Support blocks 593
can include bushings or other suitable bearing surfaces for sliding
generally parallel rails 596. Rails 596 are fixed to support plate
552 (one rail 596 associated with each side portion 553 in FIG.
23), and rails 596 extend along their lengths in the Z direction.
Accordingly, shaft 592 can be positioned along rails 596 to
position the probe mount 520 and probe assembly 638 in a desired Z
direction location. A locking mechanism (not shown) can be
associated with each support block 593 to lock the shafts 592 (and
so probe assembly 638) in a desired Z direction location.
[0107] One or more fiducial markers can be attached to one or both
of the plates 542 and 552 to present an artifact which is
detectable in a magnetic resonance image. In FIG. 23 a fiducial
marker 700 is shown positioned on breast compression plate 542. 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 of plates 542 and 552 to
identify the Y position of the plates' position along rails 572. A
position encoder can be associated with one or both of blocks 593
to identify the position of the blocks in the Z direction along
rails 596. A position encoder can be associated with the probe
mount 520 to identify the position of the mount 520 in the X
direction along shafts 592. 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. rails 572), 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. blocks 593). 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 tip 640).
[0108] In FIG. 23, rails 572 provide a first pair of generally
parallel, elongated sliding supports oriented in a first direction
(Y), and rails 596 provide a second pair of generally parallel,
elongated sliding supports oriented in a second direction (Z)
perpendicular to the first direction. Biopsy probe support plate
552 is adapted to support the biopsy probe 638 in a position that
is everywhere between the two parallel rail supports 572 (when
viewed along the Z axis) and between the two rail parallel supports
596 (when viewed along the Y axis), and with biopsy probe 638 being
supported on probe mount 520 for sliding movement along a third
direction (X) perpendicular to the first and second directions.
Positioning the support rails 572 and 596, one each on each side of
probe assembly 638, so that the probe assembly is between each pair
of generally parallel supports, can be helpful in minimizing probe
misalignment and positioning inaccuracy.
[0109] In using the apparatus of FIG. 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. The probe assembly 638 can then be mounted on probe
mount 520 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. The probe assembly mount 520 is then moved along shafts 592
in the X-axis direction the calculated relative distance and its
position along the X-axis is fixed with the locking mechanism. The
probe assembly mount 520 is then moved in the Z direction by
sliding blocks 593/shafts 592 on rails 596 the calculated relative
distance and its position along the Z-axis is fixed. Lastly, the
probe assembly needle tip 640 is inserted into the breast by
advancing the probe support plate 552 along the Y-axis on rails 572
the calculated relative distance to the predetermined biopsy site
and its position is fixed along the Y-axis. The actual biopsy is
then performed.
[0110] FIG. 24 provides an isometric schematic illustration of a
biopsy probe assembly (designated 938) and a probe mount
(designated 820) incorporating a spring loaded "ball detent"
mechanism for use in releasably attaching the probe assembly to the
probe mount. In FIG. 24, probe mount 820 is shown supported for
sliding motion in the X direction on a shaft support designated
892. Shaft 892 can include splines (not shown) or otherwise have a
non-circular cross-section. Biopsy probe assembly 938 in FIG. 24
includes an engagement tang 980 which extends vertically downward
from the body of the biopsy probe assembly 938. Engagement tang 980
includes oppositely facing grooves 984 machined or otherwise formed
in opposite side faces 982 of tang 980.
[0111] Probe mount 820 includes an opening 824 in a top surface of
the mount 820 sized for receiving the engagement tang 980. Opening
824 can extend through the fully thickness of mount 820, or extend
partially through mount 820. A pair of spring loaded ball
assemblies 830 can be disposed in cylindrically shaped holes 828
extending from opposite side surfaces of mount 820, the holes 828
communicating with opening 824. The spring loaded ball assemblies
830 can include: a ball 832 sized and shaped to engage a groove 984
in tang 980; a biasing element, such as a spring 834 for urging
ball 832 into engagement with groove 984; and a plug 836 or other
suitable mechanism for securing the ball and spring in probe mount
820. Suitable spring and ball assemblies can be purchased
commercially. A user can, with a single hand, grasp the probe
assembly 938 and engage the probe assembly with the probe mount 820
by pushing the tang 980 downward into the opening 824 until the
balls 832 of the mount engage the grooves 984 of the tang. The
biasing force provided by the springs 834 assist in holding the
biopsy probe assembly 938 in a fixed position with respect to the
probe mount 820, and can reduce clearances that otherwise could
result in positioning errors. The user can disengage the probe
assembly 938 from the probe mount 820 with a single hand by pulling
upwardly on the probe assembly 938 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 in FIG. 24, other suitable release mechanisms may be
substituted for releasably coupling the biopsy probe assembly to
the biopsy probe mount.
[0112] FIG. 25 is an isometric cut-away illustration of a three
piece clamp 1376 useful in the present invention. Clamp 1376
includes a housing body 1410, which can include a generally
cylindrical through bore 1420 for receiving a bushing or other
bearing member, such as a bushing 374, and a shaft, such as shaft
372. Body 1410 can also include a radially extending assembly
access aperture 1424 which can communicate with bore 1420 through a
hole in bushing 374. Clamp 1376 also includes a toggle lever 1440,
a clamp actuation rod 1450, a pin 1454 extending through a hole in
rod 1450 and through a clevis in lever 1440 to pivotably connect
lever 1440 to rod 1450. The pin 1454 passes through rod 1450 near a
top end of rod 1450, and a shaft engaging member, such as pad 1460
is attached to an opposite second end of rod 1450. The pad 1460 can
extend through an cylindrically shaped whole in bearing 374. The
pad 1460 can have a bottom surface shaped to accommodate a diameter
of shaft 372 (e.g. a shape generated by the surface of intersection
of two perpendicular cylinders), and the pad 1460 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. shaft 372). A biasing
member, such as a coil spring 1470 can be disposed in a recess 1426
in housing body 1410. Coil spring can be positioned around rod 1450
and can urge pad 1460 downward into engagement with shaft 372 when
the lever 1440 is in the horizontal position shown in FIG. 25. This
first horizontal position of lever 1440 corresponds to a shaft lock
position. The lever 1440 can be rotated as indicated by arrowhead
1498) to a second position where the lever is generally vertically
upright (see FIG. 26), such that rotation of the lever 1440 raises
pin 1454 vertically, and so raises pad 1460 up out of engagement
with shaft 372 to unlock shaft 372. Lever 1440 has a surface 1442
which abuts against a top surface of housing 1410 to maintain lever
1440 in the upright second position once lever 1440 has been
rotated (counter-clockwise in FIG. 25) to that position. Surface
1442 can be spaced a distance from the axis 1454 so that when lever
1440 is rotated and surface 1442 is positioned to abut the housing
1410, the pin 1454 is raised with respect to the housing, thereby
raising rod 1450 and pad 1460 against the biasing force of spring
1470. A third lever position corresponds to applying a downward
pressing force on lever 1440, in a direction shown by arrowhead
1499. Pressing downward on lever 1440 causes lever 1440 to rock or
pivot about a surface 1412 on housing 1410, thereby raising pin
1454 and rod 1450 to lift pad 1460 out of engagement with shaft
372.
[0113] FIGS. 26 and 27 are perspective illustrations showing use of
the three position clamp 1376 with the fixture assembly 316 shown
in FIG. 22. In FIG. 26, the fixture assembly 316 is shown prior to
attaching the biopsy probe assembly to probe mount 320. FIG. 26
shows clamps 1376B in a locked (first) position and clamps 1376A in
an unlocked (second) position. With clamps 1376B in the locked
position, compression plate 342 and biopsy probe support plate 352
can be pushed together toward breast tissue (not shown) to compress
the breast. In FIG. 26, upright levers 1440 of clamps 1376A extend
above (along Z direction) a lower portion of the side portions 353
of plate 352.
[0114] Once the beast compression plate 342 is in position,
compressing tissue, it is desirable to lock the position of plate
342 and then move plate 352 back, away from plate 342 along the Y
axis so that a biopsy probe device can be attached to probe mount
320. FIG. 27 shows locking clamps 1376B with levers 1440 in an
unlocked (second) position so that shaft 382 and plate 352 (to
which shaft 382 is attached) can slide along the Y axis away from
compression plate 342. FIG. 27 also illustrates how movement of
plate 352 relative to plate 342 automatically locks compression
plate 342 relative to shaft 372 (and so fixes plate 342 against
breast tissue). In FIG. 27, movement of plate 352 relative to plate
342 causes plate side portion 353 to engage upstanding levers 1440
locking clamps 1376A, forcing rotation of levers 1440 to the locked
(first) position, and thereby locking the Y position of plate 342
on shafts 372. 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 of FIG. 27 will
automatically lock the position of the compression plate upon
retraction of the biopsy probe support plate 352. Once the plate
352 has been moved back along the Y axis relative to the
compression plate 342, the biopsy probe assembly 438 can be
attached to the probe mount 320.
[0115] 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
a localization mechanism 316/516 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 two shafts
372/572 are shown in FIGS. 22 and 23, it may be desirable in other
embodiments to have a single shaft 372 (or 572), such as a shaft
mounted to the side of, or centered with respect to, plates 342 and
352.
[0116] 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.
[0117] 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.
[0118] 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.
* * * * *