U.S. patent application number 10/559404 was filed with the patent office on 2007-11-29 for integrated x-ray and ultrasound medical imaging system.
Invention is credited to Guy M. Besson, Morgan W. Nields.
Application Number | 20070276233 10/559404 |
Document ID | / |
Family ID | 33490036 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070276233 |
Kind Code |
A1 |
Besson; Guy M. ; et
al. |
November 29, 2007 |
Integrated X-Ray and Ultrasound Medical Imaging System
Abstract
An integrated x-ray and ultrasound medical imaging system is
provided, wherein a radiation detection means and ultrasound
transducer may be disposed for scanning movement for image
acquisition along either the same or substantially coincidental
paths. The radiation detection means and ultrasound transducer may
be advantageously located on the same side of the imaged body
portion: The x-ray and ultrasound imaging operations may be
sequential, partially overlapping, or synchronous. By virtue of the
noted arrangement, increased accuracy and medical efficiencies can
be realized.
Inventors: |
Besson; Guy M.; (Broomfield,
CO) ; Nields; Morgan W.; (Englewood, CO) |
Correspondence
Address: |
COOPER & DUNHAM, LLP
1185 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
33490036 |
Appl. No.: |
10/559404 |
Filed: |
June 4, 2004 |
PCT Filed: |
June 4, 2004 |
PCT NO: |
PCT/US04/17770 |
371 Date: |
September 25, 2006 |
Current U.S.
Class: |
600/437 ;
378/21 |
Current CPC
Class: |
A61B 8/565 20130101;
A61B 6/488 20130101; A61B 6/4417 20130101; A61B 6/502 20130101;
A61B 6/563 20130101; A61B 8/0825 20130101; A61B 6/5247 20130101;
A61B 8/4416 20130101 |
Class at
Publication: |
600/437 ;
378/021 |
International
Class: |
A61B 6/03 20060101
A61B006/03 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2003 |
US |
10455878 |
Claims
1. An apparatus for use in generating images of a selected region
of a patient's body, comprising: a radiation source for
transmitting a radiation signal through a selected region of a
patient's body; radiation detection means, positionable for
scanning movement along a first path, for receiving, a portion of
said radiation signal passing through a selected region of a
patient's body during said scanning movement and providing a first
image signal responsive thereto; and an ultrasound transducer,
positionable for scanning movement along a second path, for
receiving an ultrasound signal from a selected region of a
patient's body during said second movement and providing a second
image signal responsive thereto, wherein said second path is one of
the same and substantially coincidental to said first path.
2. An apparatus as recited in claim 1, wherein a selected region of
a patient's body is positionable so that said radiation source is
on a first side thereof and said radiation detection means and said
ultrasound transducer are both positioned on an opposing, second
side thereof.
3. An apparatus as recited in claim 2, further comprising: a
support layer having a first side for contacting a selected region
of a patient's body and an opposing second side, wherein said
radiation detection means and said ultrasound transducer are both
located adjacent to said second side of the supporting layer.
4. An apparatus as recited in claim 3, wherein said first side of
the support layer is of an arcuate configuration.
5. An apparatus as recited in claim 4, wherein said first path is
arcuate.
6. An apparatus as recited in claim 3, wherein said first side of
the support layer is of a planar configuration.
7. An apparatus as recited in claim 6, wherein said second path is
linear.
8. An apparatus as recited in claim 1, further comprising:
processor means for controlling operation of said radiation source,
radiation detection means and ultrasound transducer, wherein said
radiation detection means and said ultrasound transducer are
controllable for at least partially overlapping imaging
operations.
9. An apparatus as recited in claim 8, further comprising: drive
means for effecting co-scanning movement of said radiation
detection means and said ultrasound transducer.
10. An apparatus as recited in claim 9, wherein said radiation
detection means and said ultrasound transducer are interconnected
in fixed relation to one another.
11. An apparatus as recited in claims 10, wherein one of said
radiation detection means and said ultrasound transducer is
supportably carried by the other.
12. An apparatus as recited in claim 1, wherein said radiation
detection means is maintained at a substantially fixed distance
from said radiation source throughout said scanning movement
thereof.
13. An apparatus as recited in claims 1, wherein said radiation
detection means comprises an array of detector elements and said
ultrasound transducer comprises an array of transducer elements,
and wherein said arrays are oriented in like relation relative to
said first path and second path, respectively.
14. An apparatus as recited in claims 1, wherein at least one said
radiation detection means and said ultrasound transducer is of a
width that is less than a width of a selected region of a patient's
body to be imaged.
15. An apparatus as recited in claims 1, wherein said radiation
detection means and said ultrasound transducer have corresponding
widths which are each less than a width of a selected region of a
patient's body to be imaged.
16. An apparatus as recited in claims 15, wherein said radiation
detection means and said ultrasound transducer have corresponding
lengths which are each at least as great as a length of a selected
region of a patient's body to be imaged.
17. An apparatus as recited in claim 1, further comprising: a
display for displaying a plurality of images of said selected body
region generated using said first and second image signals; and, a
user input for selecting a desired image by identifying a location
of interest in a different image.
18. An apparatus as recited in claim 1, wherein a pair of
ultrasound transducers are positionable for scanning movement along
substantially parallel paths, wherein one of said pair is located
on a first side of said selected body region and the other of said
pair is located on an opposing second side of said selected body
region.
19. A method for use in obtaining image data for a selected region
of a patient's body, comprising: transmitting a radiation signal
from a radiation source through a selected region of a patient's
body; moving a radiation detection means along a first path during
said transmitting step, wherein said radiation detection means
receives a portion of said radiation signal passing through a
selected region of a patient's body and provides a first image
signal responsive thereto; and, displacing an ultrasound transducer
along a second path that is one of the same and substantially
coincidental to said first path, wherein said ultrasound transducer
receives an ultrasound signal from said selected region of a
patient's body and provides a second image signal responsive
thereto.
20. A method as recited in claim 19, further comprising:
immobilizing said selected region of a patient's body within a
predetermined frame of reference, wherein said transmitting, moving
and displacing steps are completed during said immobilizing
step.
21. A method as recited in claim 20, wherein said mobilizing step
includes: compressing said selected region of a patient's body.
22. A method as recited in claim 19, Wherein said radiation source
is located on a first side of said selected body region and said
radiation detection means and said ultrasound transducer are both
positioned on an opposing second side thereof.
23. A method as recited in claim 19, wherein said moving and
displacing steps at least partially overlap.
24. A method as recited in claim 23, wherein said moving and
displacing steps are completed in substantial synchronicity.
25. A method as recited in claim 19, wherein said moving and
displacing steps are completed sequentially.
26. A method as recited in claim 19, wherein said ultrasound
transducer transmits said ultrasound signal into said selected body
region during said displacing step.
27. A method as recited in claim 19, wherein said displacing step
includes: displacing a pair of ultrasound transducers along
substantially parallel paths, wherein one of said pair is located
on a first side of said selected body region and the other of said
pair is located on an opposing second side of said selected body
region, and wherein said pair provide second image signals.
28. A method as recited in claim 19, further comprising: selecting
a desired image for display by identifying a location of interest
in a different displayed image.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to medical imaging systems,
and more particularly, to an improved system that combinatively
employs x-ray imaging and ultrasound imaging in a manner thai
yields enhanced accuracy and multiple efficiencies.
BACKGROUND OF THE INVENTION
[0002] The advantages of early detection of potential lesions and
suspicious masses within bodily tissue have been well-established.
Increasingly, screening for common cancers of the breast, lung,
colon, and prostate has gained support and acceptance in the
medical community, but improvements in the sensitivity and
specificity of the techniques remain key and are readily
identifiable objectives.
[0003] Of particular interest is the area of mammographic
screening. After a given age or maturity, normally beginning at age
40, it is common for women to undergo periodic examinations,
wherein film-based and/or digital x-ray screening mammograms are
obtained. While significant advances have been made, current
screening approaches may provide mammograms with insufficient
"sensitivity" to allow for the detection of the presence of a
potential lesion, thereby resulting in a "false negative". Further,
current screening approaches may provide mammograms with
insufficient "specificity" to allow for accurate characterization
of detected suspicion tissue masses, thereby potentially resulting
in "false positives".
[0004] Presently, in the event of an equivocal screening mammogram,
a callback examination may be conducted, wherein a diagnostic
mammogram is obtained and/or an ultrasound imaging procedure is
performed, thereby entailing another patient office visit,
additional medical personnel time and increased cost. More
particularly, an ultrasound examination may be utilized (e.g. as
opposed to a biopsy) to rule out the presence of a solid mass. In
this regard, current practice can entail free-hand ultrasound
imaging during which a specialist manipulates a hand-held probe
relative to a patient's breast while viewing a display to obtain
depth-profile information. As may be appreciated, the ability to
mentally correlate such depth-profile information with the location
of a potential lesion/suspicious mass visualized on an x-ray image
can be quite challenging, thereby sometimes compromising
characterization efforts. Moreover, such procedures are time
consuming and entail significant expertise. These considerations
present significant limitations to the realization of increased
efficacies and efficiencies of practice.
SUMMARY OF THE INVENTION
[0005] In view of the foregoing, a primary objective of the present
invention is to provide a medical imaging system that reduces
instances of undetected malignancies (e.g. false negatives) and/or
falsely characterized non-malignancies (e.g. false positives) by
providing increased sensitivity and specificity.
[0006] Another objective of the present invention is to provide a
medical imaging system that reduces the need of callbacks for
patients undergoing screening examinations.
[0007] Yet another objective of the present invention is to provide
a medical imaging system that improves overall efficiencies in the
delivery of medical screening services.
[0008] A further objective of the present invention is to provide a
medical imaging system that is patient and user-friendly in
implementation, including in particular patient screening
applications.
[0009] One or more of the above objectives and additional
advantages are realized by the present invention. An inventive
apparatus includes a radiation source for transmitting a radiation
signal through a selected region of a patient's body, and a
radiation detection means for receiving a portion of the radiation
signal passing through the selected body region and providing a
first image signal responsive thereto. Further, the apparatus
includes at least one ultrasound transducer for sending/receiving
an ultrasound signal into/from the selected region of the patient's
body and providing a second image signal responsive thereto. The
radiation detection means and ultrasound transducer may be disposed
in known spatial relation to a predetermined imaging frame of
reference in which the selected body region may be immobilized,
wherein the first and second image signals may be readily
correlated and otherwise processed for the generation and display
of images to medical personnel (e.g. specialists located at a
patient screening site or a networked location).
[0010] More particularly, and in one aspect, the inventive
apparatus may be provided so that the radiation detection means and
ultrasound transducer are each operable for scanning movement
relative to the selected body region along the same or
substantially coincidental paths during image acquisition (e.g.
parallel, linear or arcuate paths). In this regard, the radiation
detection means and ultrasound transducer may each be of a width
that is less than a width of the selected body region, wherein the
noted scanning movement allows the entirety of the selected body
region to be progressively, or incrementally, imaged with enhanced
results. For example, the radiation signal may be substantially
focused upon and scanned in synchronous relation with the radiation
detection means to reduce scattering effects and otherwise yield
high detection quantum efficiencies. Relatedly, it may be
preferable for one or both of the radiation detection means and
ultrasound transducer to have corresponding lengths that are at
least as great as the length of the selected body region. In turn,
image acquisition for the entire selected body region may be
achieved via a single scanning movement, or pass, of the radiation
detection means and/or ultrasound transducer across the width of
selected body region, wherein temporal decorrelation effects may be
reduced. Alternatively, one or both of the radiation detection
means and ultrasound transducer may be of a length that is less
than the length of the selected body region, wherein a plurality of
scanning movements along parallel paths may be utilized (e.g. via
raster, bi-directional or return carriage, unidirectional imaging
arrangements).
[0011] The radiation detection means may comprise an array of
radiation detector elements and the ultrasound transducer may
comprise an array of ultrasound transducer elements, wherein each
of the arrays are positioned or positionable in known spatial
relation relative to the imaging frame of reference. Further, the
array of radiation detector elements and array of ultrasound
transducer elements may be positioned or positionable so that the
row(s)/column(s) thereof are disposed in a like relationship
relative to their respective scanning travel paths. For example,
the element row(s) of each of the arrays may be oriented
substantially perpendicular to their corresponding scanning travel
paths and the element column(s) of each of the arrays may be
oriented substantially parallel to their corresponding scanning
travel paths, wherein such scanning travel paths are the same or
substantially coincidental.
[0012] To effect scanning movement, the radiation detection means
and ultrasound transducer may be operably interconnected to a
common or separate corresponding drive means (e.g. one or more
stepper motor(s)) for moving the radiation detection means and
ultrasound transducer in a controlled manner relative to the
predetermined imaging frame of reference. Preferably, the drive
means may be provided so that the radiation detection means and
ultrasound transducer may each be scanned at corresponding
predetermined and substantially constant velocities, wherein such
velocities may be the same or different. For example, the detection
means and ultrasound transducer may be driven for at least
partially synchronous scanning, preferably at substantially the
same, constant velocity. Alternatively, radiation and ultrasound
scanning may be conducted sequentially at the same or different
corresponding velocities as may be desired due to varying
acquisition system bandwidths.
[0013] The radiation source and radiation detection means may be
provided to maintain a substantially fixed distance therebetween
throughout scanning. In this regard, the radiation source may be
rotatable about and have a focal point located on a substantially
fixed axis, and the radiation detection means may be disposed for
movement along an arcuate path centered at the focal point of the
radiation source during imaging. Further, the ultrasound transducer
may also be provided for movement along a coincidental, arcuate
path or along a linear path during imaging.
[0014] In another aspect, the inventive apparatus may be provided
so that the ultrasound transducer is disposed for scanning
co-movement with and in fixed relation to the radiation detection
means. In this regard, the radiation detection means and ultrasound
transducer may be physically interconnected or interconnectable.
For example, one of the radiation detection means and ultrasound
transducer may be supportably carried by the other, wherein the
carrier is supportably interconnected to a drive means.
Alternatively, the radiation detector and ultrasound transducer may
each be interconnected or interconnectable in known spatial
relation to a common support member.
[0015] According to a further aspect of the present invention, the
inventive apparatus may be provided so that a selected region of
the patient's body is positionable with (i.) the radiation source
on a first side thereof, and (ii.) the radiation detection means
and ultrasound transducer on an opposing, second side thereof. In
one arrangement, the selected body region may be located in contact
relation with a first side of a support layer, wherein the
radiation detection means and ultrasound transducer are located or
locatable on an opposing second side of the support layer for
imaging through the support layer. As may be appreciated, the
support layer should be both radiolucent and sonolucent to
accommodate the passage of x-ray and ultrasound imaging signals
therethrough. Further, an acoustic coupling means may be positioned
or positionable in contact relation with both the ultrasound
transducer and the second side of the support layer. For example,
the acoustic coupling means may be sonolucent and flowable (e.g.
conformable) to facilitate an acoustic interface between the
ultrasound transducer and support layer.
[0016] The support layer may be of an arcuate or planar (e.g. flat)
configuration and may be of rigid or pliable construction. In turn,
to facilitate the maintenance of a contact relationship between the
ultrasound transducer, acoustic coupling means, support layer and
selected body region, the ultrasound transducer may be disposed for
scanning movement along a travel path that substantially coincides
with the shape of the support layer (e.g. a coincidental arcuate or
linear path). Additionally, to facilitate contact maintenance, the
ultrasound transducer may be disposed for movement toward and away
from the second side of the support layer during scanning movement.
For example, the ultrasound transducer may be biased toward the
support layer (e.g. spring-loaded along a slot mount in a support
bracket). Further, the ultrasound transducer may be disposed to
permit the pitch and/or attitude of the ultrasound transducer (e.g.
relative to the support layer) to automatically adjust in response
to local shape variations (e.g. variations caused by local tissue
variations of a compressed breast deforming a pliable support
member). For example, an ultrasound transducer may be mounted to a
support bracket via a ball-joint or gimbal arrangement.
[0017] In yet a further aspect of the present invention, the
inventive apparatus may include a processor means for controlling
operation of the radiation source, radiation detection means,
ultrasound transducer and scanning drive means. More particularly,
the processor means may control the drive means to effect scanning
movement of and imaging operations by the radiation detection means
and ultrasound transducer in a sequential, partially overlapping or
substantially synchronous manner.
[0018] Various embodiments of the inventive apparatus may employ
one or more of the above-noted aspects and further additional
features. Of note, the inventive apparatus may include a user
interface means for displaying a plurality of images of the
selected body region that are generated by the processor means
utilizing image data obtained from the first and/or second image
signals. More particularly, the user interface means may include a
display and a user input for controlling the processor means,
wherein a first image may be displayed and utilized to select at
least a second image. For example, a user input (e.g. a mouse) may
be provided to control positioning of a cursor relative to a region
of interest on a displayed projection image generated from the
x-ray image data (e.g. a projected XY plane image), wherein upon
locating the cursor and corresponding user input (e.g. via clicking
a mouse button), corresponding cross-cut, z-depth plane images may
be generated by the processor means from the ultrasound image
dataset and displayed to a user (e.g. YZ and XZ plane images
extending through the region of interest). Further, the cursor may
be positioned relative to a region of interest on one of the YZ or
XZ plane images to obtain a desired XY plane image at a selected Z
elevation, wherein such image is generated by the processor means
from the ultrasound image dataset. As may be appreciated, the
ultrasound image dataset may also be utilized to generate
three-dimensional images of a region of interest.
[0019] In other embodiments a pair of ultrasound transducers may be
utilized. For example, a first ultrasound transducer may be
disposed on a first side of the selected body region and a second
ultrasound transducer may be located on an opposing, second side of
the selected body region, wherein the first and second ultrasound
transducers are preferably disposed in opposing, aligned relation.
More particularly, the first ultrasound transducer may be disposed
in contact relation with first acoustic coupling means which is
disposed in contact relation with a support layer as described
hereinabove. The second ultrasound transducer may be disposed in
direction contact with a second acoustic coupling means that is
disposed in contact relation with a compression member, wherein the
selected body region is immobilized in contact relation between the
support layer and the compression member. The utilization of a pair
of ultrasound transducer allows for the obtainment of various
tissue properties corresponding with the selected body region. For
example, an ultrasound signal may be transmitted by the first
ultrasound transducer and received by the second ultrasound
transducer to yield tissue attenuation and/or signal velocity
information, both of which types of information may be utilized to
facilitate characterization of tissue masses within the selected
body region.
[0020] In yet further embodiments, an ultrasound image dataset
obtained via one or a pair of ultrasound transducers may be
processed to obtain Doppler image data. In turn, the Doppler image
data may be utilized to measure the direction and velocity of blood
flow in a tissue region of interest and to provide a visual display
thereof (e.g. a color Doppler image).
[0021] As may be appreciated, an inventive method is also provided
for use in obtaining image data with respect to a selected region
of a patient's body. The inventive method includes the steps of
transmitting a radiation signal from a radiation source through the
selected body region and moving a radiation detection means along a
first path during the transmitting step, wherein the radiation
detection means receives a portion of the radiation signal passing
through the selected body region and provides a first image signal
responsive thereto. The method further includes a step of
displacing an ultrasound transducer along a second path, wherein
the ultrasound transducer sends/receives an ultrasound signal from
the selected body region as it travels along said second path and
provides a second image signal responsive thereto. The method may
further provide for processing the first and second image signals,
and for the selective display of resultant images to medical
personnel.
[0022] In conjunction with the inventive method, the selected body
region may be immobilized within a predetermined frame of
reference, wherein the transmitting, moving and displacing steps
are completed during the immobilization step. Further, the
immobilization step may provide for compression of the selected
body region.
[0023] According to one aspect, the method may entail movement of
the radiation detection means and displacement of the ultrasound
transducer along corresponding first and second paths which are the
same or substantially coincidental (i.e. parallel, linear or
arcuate paths). By way of example, the radiation detection means
and ultrasound transducer may be directly interconnected or
interconnectable or to a common support means for driven movement.
Additionally, the transmitting step may include scanning the
radiation signal across the selected body region synchronous with
and in the same direction as the radiation detection means.
Further, the radiation signal may be substantially focused upon the
radiation detection means during imaging, wherein radiation dosages
are reduced and image resolutions are enhanced.
[0024] In another aspect, the inventive method may provide for
positioning of the radiation detection means and ultrasound
transducer on the same side of a selected body region of the
patient. By way of example, a first side of a support layer may be
located adjacent to the selected body region, wherein the radiation
detection means and ultrasound transducer may be located on an
opposing second side of the support layer for scanning movement. To
facilitate ultrasound imaging, acoustic coupling means may be
utilized on each side of the support layer. For example, an
acoustic coupling member (e.g. a conformable pad containing a
flowable acoustic gel) may be interposed between and in direct
contact with the first side of the support layer and the selected
body region.
[0025] Further in this regard, an acoustic coupling member (e.g. a
conformable pad containing a flowable acoustic gel) may be
interposed between the ultrasound transducer and the second side of
said support layer in direct contact with each. By way of example,
the acoustic coupling member may be interconnected to the
ultrasound transducer, wherein the acoustic coupling member
slidably engages the support layer during scanning displacement.
Alternatively, the acoustic coupling member may be interconnected
to the second side of the support layer, wherein the ultrasound
transducer slidably engages the acoustic coupling member during
scanning displacement. In such an arrangement, processing of the
first image signal may include an adjustment to account for x-ray
attenuation associated with the passage of the radiation signal
through the acoustic coupling member. In one approach, to
facilitate such an adjustment, the inventive method may initially
provide for transmission of the radiation signal and movement of
the radiation detection means along the first scanning path prior
to actual imaging of said selected body region. Concomitantly, the
radiation detection means may receive a portion of the radiation
signal passing through the acoustic coupling member and provide a
calibration output signal responsive thereto. In turn, the
calibration signal may be stored/utilized in conjunction with the
above-noted image processing adjustment.
[0026] To further facilitate ultrasound imaging, an acoustic gel or
other ultrasound couplant may be applied to the selected body
region to be imaged and/or to the support layer prior to imaging to
enhance the acoustic interface therebetween.
[0027] In another aspect of the inventive method, scanning movement
of the radiation detection means and scanning displacement of the
ultrasound transducer for body imaging may occur in at least a
partially overlapping manner. For example, the moving and
displacing steps for radiation and ultrasound imaging may be
completed in substantial synchronicity. In another approach,
scanning movement of the radiation detection means and scanning
displacement of the ultrasound transducer for body imaging may be
completed sequentially.
[0028] Additional aspects and advantages of the present invention
will become apparent to those skilled in the art upon consideration
of the further description provided hereinbelow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates one embodiment of an imaging system
comprising features of the present invention.
[0030] FIGS. 2A-2C are cross-sectional front views of an imaging
station of the embodiment of FIG. 1, wherein progressive tandem,
scanning movement of an x-ray detector and ultrasound imager is
illustrated.
[0031] FIG. 3A is a perspective cutaway and partial exploded
assembly view of one imaging assembly embodiment of the system
embodiment of FIG. 1.
[0032] FIG. 3B is a perspective cutaway and partial exploded
assembly view of another imaging assembly embodiment of the system
embodiment of FIG. 1.
[0033] FIG. 4 is a cross-sectional front view of another embodiment
of an imaging station comprising dual ultrasound transducers.
[0034] FIG. 5 illustrates an exemplary patient breast located
within a predetermined imaging frame of reference and potential
image plane views that may be generated.
[0035] FIG. 6A illustrates an exemplary projected x-ray image and
ultrasound image that may be displayed via use of the radiation
image signal and ultrasound image signal obtained in various
embodiments of the present invention.
[0036] FIG. 6B illustrates various two-dimensional images that may
be displayed via use of the radiation image signal and ultrasound
image signal obtained in various embodiments of the present
invention.
[0037] FIG. 7 is a high-leveled diagram showing various steps of
method embodiments of the present invention.
DETAILED DESCRIPTION
[0038] FIG. 1 illustrates one embodiment of an imaging system
comprising the present invention. The system includes a monitoring
station 10 and imaging station 20 operatively interconnected
thereto, e.g. for patient screening and/or follow-up examination.
The monitoring station 10 includes a user input keyboard 12 (e.g.
for entering patient data), a display 14 and corresponding user
input mouse 13 (e.g. for displaying/selecting images), and a
processor 16 interconnected to the user input keyboard 12, display
14 and imaging station 20. Processor 16 is adapted to receive,
process and store image data comprising image signals generated at
the imaging station 20, and to control various operations at the
imaging station 20. The monitoring station 10 may also include a
radiopaque and optically transparent shield 18 for shielding
medical personnel during observed patient imaging operations at the
imaging station 20.
[0039] The monitoring station 10 and/or imaging station 20 may be
further interconnected or interconnectable in a network arrangement
with other user workstations and image processor/storage sites 300.
For example, image data obtained at imaging station 20 may be
provided to a networked location (e.g. at a remote site) for
high-resolution display and analysis by diagnostic specialists.
[0040] The imaging station 20 may include an x-ray radiation source
22, e.g. an x-ray tube, and collimating optics and/or selectable
filters 24, for transmitting a focused radiation signal 26. By way
of example, the radiation signal 26 may comprise a fan-shaped beam.
The radiation source 22 may be disposed for controlled rotation
about a fixed axis, wherein the radiation signal 26 may be scanned
across a selected region of a patient's body.
[0041] By way of primary example, a patient's breast may be located
within a predetermined imaging frame of reference located
immediately adjacent to an imaging assembly 30. More particularly,
a patient breast may be immobilized between a support layer of the
imaging assembly 30 and a compression member 28. The compression
member 28 may be selectively raisable/lowerable relative to the
imaging assembly 30. Further, the radiation source 22, compression
member 28 and imaging assembly 30 may be supportably mounted to an
upper station member 21 that is supportably connected to and
selectively raisable/lowerable/rotatable relative to a pedestal
station member 23. By virtue of such arrangement, the compression
member 28 and imaging assembly 30 may be selectively positioned to
accommodate varying patient heights, breast sizes and x-ray imaging
angles.
[0042] As previously noted, radiation signal 26 may be scanned
across a selected region of a patient's body, e.g. a patient's
breast. In this regard, radiation source 22 may be interconnected
to a rotatable shaft 25 (e.g. for co-rotation therewith), wherein a
focal point of the radiation source 22 is located on a
substantially fixed center axis of the rotatable shaft 25. In turn,
a top end of a pendulum member 27 may be interconnected to
rotatable shaft 25, wherein the pendulum member 27 may pivot about
the center axis of shaft 25 when shaft 25 rotates.
[0043] A bottom end the pendulum member 27 may be interconnected to
a drive motor 60 (e.g. a stepper motor), and to an x-ray detector
40 and ultrasound imager 50 comprising imaging assembly 30. In this
regard, the drive motor 60 may be selectively operated to move the
x-ray detector 40 and ultrasound imager 50 along corresponding
arcuate scanning travel paths. In the illustrated arrangement,
operation of drive motor 60 will also effect synchronized scanning
of the radiation signal 26 along a coincidental arcuate path by
virtue of the operative interconnection of drive motor 60 to
radiation source 22 via pendulum member 27 and shaft 25.
[0044] Further in this regard, drive motor 60 may comprise an
output shaft 62 that travels along a cam surface 70 of a cam member
72 (e.g. mounted to-upper station member 21) upon rotation of the
output shaft 62. More particularly, an arrangement may be provided
as disclosed in U.S. Patent No. 5,917,881, entitled "DIGITAL SCAN
MAMMOGRAPHY APPARATUS UTILIZNG VELOCITY ADAPTIVE FEEDBACK AND
METHOD", hereby incorporated by reference, or U.S. Pat. No.
5,526,394, entitled "DIGITAL SCAN MAMMOGRAPHY APPARATUS", hereby
incorporated by reference.
[0045] Reference will now be made to FIGS. 2A-2C for further
description of the imaging assembly 30, as shown in imaging
relation to a patient's breast 100. As noted above, imaging
assembly 30 includes an x-ray detector 40 and ultrasound imager 50.
The x-ray detector 40 receives at least a portion of the radiation
signal 26 passing through a patient's breast 100 and provides a
digital x-ray image signal in response thereto. Ultrasound imager
50 transmits/receives ultrasound signals into/from a patient's
breast 100 and provides a digital ultrasound image signal in
response thereto.
[0046] The x-ray detector 40 and ultrasound imager 50 may be
located within a housing 32 having a support layer 36. The x-ray
detector 40, ultrasound imager 50 and drive motor 60 may be
interconnected to a bracket member (not shown) that is
interconnected to the bottom end of the pendulum member 27. As
noted, the drive motor 60 may be operated to effect radiation
signal 26 scanning and scanning displacement of the x-ray detector
40 and ultrasound imager 50 along the same path or substantially
coincidental paths relative to the predetermined imaging frame of
reference. In that regard, each of radiation source 22, x-ray
detector 40, ultrasound imager 50 and the drive motor 60 may be
operatively interconnected (e.g. via electrical and/or optical
lines) to the processor 16 at monitoring station 10, wherein
control signals are provided by processor 16 and image signals are
received at processor 16 from the imaging station 20.
[0047] In the embodiment shown in FIGS. 2A-2C, the ultrasound
imager 50 and x-ray detector 40 are physically interconnected by a
linkage member 82. The linkage member 80 may be provided so that
ultrasound imager 50 and x-ray detector 40 may be selectively
interconnected and disconnected (e.g. via mating engagement between
complimentary shaft and cylinder members provided on the radiation
detector 40 and ultrasound imager 50, respectively). In another
arrangement, two separate bracket members may be interconnected to
pendulum member 27 for separate interconnection to x-ray detector
40 and ultrasound imager 50, respectively. In yet another approach,
a single bracket member may be utilized, wherein the x-ray detector
40 and ultrasound imager 50 may be separately
disconnected/interconnected thereto for sequential imaging
operations.
[0048] To accommodate x-ray imaging operations, the compression
member 28 should be radiolucent. For example, a low density,
thermoplastic material may be employed. The support layer 36 of
housing 32 should be both radiolucent and sonolucent. For example,
a low-density thermoplastic having a relatively small x-ray
attenuation coefficient may be employed. In one arrangement, a
crystalline, or aliphatic, polymer may be utilized, such as a poly
4-methyl, 1-pentene (i.e. PMP) material, e.g. a material
commercially available under the product name "TPX" from Mitsui
Plastics, Inc., White Plains, N.Y.
[0049] As will be further described, ultrasound imager 50 may
comprise an ultrasound transducer 52 that transmits and receives
ultrasound signals. To facilitate ultrasound operations, the
ultrasound transducer 52 may be acoustically coupled to a bottom
side of the support layer 36 via an acoustic coupling means 54.
Further, an acoustic coupling means 56 may be utilized to
acoustically couple a patient's breast 100 to a topside of support
layer 36. For example, a standard ultrasound gel (e.g. a
glycerin-based gel) gel or other flowable acoustic couplant may be
contained within a pad located in contact with or otherwise applied
to either or both of the top and bottom sides of support layer 36.
Alternatively, acoustic coupling means 56 may comprise an
ultrasound-coupling, solid-disposable membrane, e.g. a SCANTAC
membrane offered by Sonotech, Inc. of Bellingham, Wash. As may be
appreciated, the use of a gel-containing pad or solid-membrane for
acoustic coupling means 56 may reduce or even avoid the need to
apply ultrasound couplants directly to a patient's breast 100,
thereby reducing set-up and clean-up procedures.
[0050] Reference is now made to the partial exploded assembly views
of FIGS. 3A and 3B. As illustrated, x-ray detector 40 may include a
light scintillator 42 (e.g. comprising a cesium iodide material), a
fiber optic plate 44 and a plurality of abutting, charged coupled
devices (CCDs) 46. When assembled, such components may be disposed
in adjacent, contact relation on a support member 48 that is
interconnected or interconnectable to a support bracket 80 that is
interconnected or interconnectable to/disconnectable from the
bottom end of pendulum member 27. As shown, drive motor 60 may also
be interconnected to pendulum member 27 via support bracket 80. As
may be appreciated, scintillator 42 produces light in response to
the receipt of radiation signal 26. In turn, such light may be
coupled via fiber optic plate 44 to a top surface of the CCDs 46
for detection and signal generation.
[0051] In the later regard, the CCDs 46 may each comprise an array
of light sensitive elements. In one arrangement, each CCD has a
405.times.2048 array of 27-micron pixels. The CCDs may be operated
in a time delay integration (TDI) mode, wherein electronic charge
is accumulated and shifted from row-to-row and readout in
synchronicity with, but in a direction opposite to, the scanning
movement travel path of the x-ray detector 40. In turn, the
resultant radiation image signal may be digitized for storage,
processing and image display at monitoring station 10.
[0052] Numerous other x-ray detector arrangements may be utilized.
For example, such arrangements may include detectors which utilize
a light scintillator, photodiodes and thin film transistor (TFT)
readout; or detectors employing direct conversion, voltage
potential and TFT readout.
[0053] With further reference to FIGS. 3A and 3B, it can be seen
that the ultrasound transducer 52 may be carried by a support
member 58. Support member 58 may be interconnected or
interconnectable to/disconnectable from the support member 48 of
radiation detector 40, e.g. by the linkage member 82 of FIGS.
2A-2C. In one alternate arrangement, the support member 58 may be
separately interconnected or interconnectable to/disconnectable
from the pendulum member 27 via a modified or separate support
bracket 80.
[0054] The ultrasound transducer 52 may comprise an array of
ultrasound transducer elements. For example, a plurality of
transducer elements with crystals operative in a 7.5-10 MHz
frequency range may be employed. As will be appreciated, the
ultrasound transducer 52 may transmit/receive an ultrasound signal
during pulse/echo operations, wherein a resultant ultrasound image
may be output and digitized for storage, processing and image
display at monitoring station 10.
[0055] The array of ultrasound transducer elements comprising
ultrasound transducer 52 may be disposed in parallel relation to
the above-noted array of light sensitive elements comprising CCDs
46. More particularly, the support members 48,58 may be provided
for interconnection therebetween and/or for separate
interconnection to drive means such as drive motor 60, wherein the
orientation of the array of light sensitive elements of CCDs 46 is
the same as the orientation of the array of transducer elements of
ultrasound transducer 52 relative to their respective scanning
travel paths and the imaging frame of reference in which a selected
body region is positioned (e.g. array rows/columns are
parallel/perpendicular to the scanning paths). As such, regardless
of whether x-ray and ultrasound imaging occur simultaneously, in
overlapping fashion, or sequentially, the corresponding images may
be readily registered in relation to the imaging frame of
reference.
[0056] As may be appreciated, the array of light sensitive elements
comprising CCDs 46, and the array of ultrasound transducer elements
comprising ultrasound transducer 52, may each be of a corresponding
width that is less than a width of a selected body region to be
imaged. In turn, and by virtue of the scanning movement of the
x-ray detector 40 and ultrasound imager 50 relative to the selected
body region, the corresponding x-ray image and ultrasound image
signals may be processed to yield full-field images of the selected
body region. Further in this regard, it may be appreciated that the
array of light sensitive elements comprising CCDs 46, and the array
of ultrasound transducer elements comprising ultrasound transducer
52, may each be of a corresponding length that is greater than the
length of a selected body region to be imaged (e.g. the
anterior-to-posterior dimension of a patient's breast 100 in FIGS.
2A-2C), wherein x-ray imaging and ultrasound imaging of the
selected body region can each be achieved via a single scanning
movement of the x-ray detector 40 and ultrasound imager 50,
respectively. Alternatively, either or both of the x-ray detector
40 and ultrasound imager 50 may be of a lesser length; e.g. the
array of ultrasound transducer 52 may be of a lesser length,
wherein the ultrasound transducer 52 may be disposed for driven
movement in a raster-like or return carriage manner for multi-pass
imaging (e.g. via bi-directional or unidirectional scanning).
[0057] Referring now to the specific arrangement illustrated in
FIG. 3A, an acoustic coupling means 54 is shown that includes a
coupling pad 55 filled with a sonolucent flowable material (e.g. a
hydrogel) located within a tray member 57 (e.g. comprising a
sonolucent material), which in turn is positioned in direct contact
with the ultrasound transducer 52. In operation, the coupling pad
55 slidably engages the bottom side of support layer 36 during
ultrasound scanning operations. To facilitate such engagement, an
acoustic lubricant (e.g. mineral oil) may be applied to the top of
the coupling pad 55.
[0058] In the arrangement illustrated in FIG. 3B, an acoustic
coupling means 54 is shown that comprises a coupling pad 59 filled
with a sonolucent flowable material (e.g. a hydrogel)
interconnected to and extending across the bottom side of support
layer 36. In turn, ultrasound transducer 50 is disposed for sliding
engagement with the coupling pad 59 during ultrasound scanning
operations. To facilitate such engagement, an acoustic lubricant
(e.g. mineral oil) may be applied to the top surface of the
ultrasound transducer 52.
[0059] In addition the above-noted arrangements, further
embodiments may employ varied structural relationships and
additional componentry. For example, in some arrangements the
ultrasound transducer 52 may be disposed and otherwise driven to
follow a substantially linear travel path during scanning
operations. Relatedly, support member 36 may be substantially
planar, wherein the travel path for the ultrasound transducer 52 is
substantially parallel to the plane defined by support layer 36. In
such an arrangement, the x-ray detector 40 may be disposed within
imaging assembly 30 to follow a substantially linear travel path or
an arcuate travel path.
[0060] In another modified arrangement, the above-noted support
member 58 may be modified to facilitate movement of the ultrasound
transducer 52 toward and away from the support layer 36. More
particularly, and by way of example, a modified bracket member 80
may be provided having a slot that extends normal to the bottom
side of support layer 36 and within which support member 58 may be
mounted for travel toward/away the support layer 36 along the slot.
For example, the support member 58 may be spring-loaded, or biased,
within the slot towards the support layer 36 so as to facilitate
engagement therewith while also allowing for the above-noted
sliding engagement between acoustic coupling pad 55 and support
layer 36 (FIG. 3A) or between the ultrasound transducer 52 and
acoustic coupling pad 59 (FIG. 3B).
[0061] Additionally, in a further modified arrangement, the support
member 58 may be provided to allow a predetermined range of
automatic pitch and/or attitude adjustment of ultrasound transducer
52. Such automatic adjustability may be provided to allow the face
of the ultrasound transducer 52 to maintain an optimal interface
via the acoustic coupling means 54 with support layer 36. By way of
example, support member 58 may implement a ball-joint or gimbal
arrangement which facilitates pivotal movement of the lateral
and/or longitudinal axes (e.g. about a common center location) of
the ultrasound transducer 52. Such arrangements may be particularly
apt where support layer 36 is of a pliable construction since the
orientation of the face of ultrasound transducer 52 may
automatically adjust to accommodate local shape changes of the
support layer 36 caused by variations in the compressed tissue
region to imaged.
[0062] FIG. 4 illustrates a further embodiment of the present
invention. Such embodiment may include the same features as
described above in relation to the embodiment of FIG. 1 and FIGS.
2A-2C and FIGS. 3A and/or 3B, and further includes a second
ultrasound imager 90. By way of example, the second ultrasound
imager 90 may be positioned on a side of a patient's breast 100
that is opposite to the side on which the above-noted ultrasound
transducer 50 is located. More particularly, the ultrasound imager
90 may be positioned in contact relation with a top surface of a
sonolucent and radiolucent compression member 28. In turn, an
ultrasound transducer 92 may provided with an acoustic coupling
member 94 which directly engages the compression member 28. The
ultrasound imager 90 may be interconnected to the above-noted
pendulum member 27 so that ultrasound imagers 50 and 90 move in
tandem and in opposing face-to-face relation during ultrasound
imaging operations.
[0063] As may be appreciated, multiple ultrasound signals may be
transmitted and/or received by the ultrasound imagers 50,90 to
obtain enhanced ultrasound information. By way of example, the
transmission and reception of ultrasound signals between the
ultrasound imagers 50,90 may yield particular information
pertaining to tissue attenuation and signal velocity.
[0064] Reference is now made to FIG. 5 which illustrates the
positioning of a patient breast 100 within a predetermined frame of
reference corresponding with the region located immediately
adjacent to the support member 36 of the imaging assembly 30 of
FIGS. 2A-2C. As will be appreciated, the image data comprising the
image signal provided by x-ray detector 40 may be utilized to
generate a projected XY plane image of the breast 100. The image
data comprising the image signal provided by the ultrasound imager
50 may be utilized to generate YZ plane images, XZ plane images and
XY plane images of the patient breast 100.
[0065] Further in this regard, and as shown in FIG. 6A, a projected
XY x-ray image and a selected XZ ultrasound image may be displayed
at the display 14 of monitoring station 10. By way of example, a
tissue region of interest 102 (e.g. a suspicious mass) may appear
in a projected XY plane image. In turn, a user may utilize the
input mouse 13 at monitoring station 10 to control the positioning
of a display cursor 14a, wherein the cursor 14a may be located on
the tissue region of interest 102 in the projected XY plane image.
When the curser position is input via mouse 13 (e.g. by a button
click) the illustrated crosscut XZ plane image may be automatically
displayed.
[0066] As may be appreciated, monitoring station 10 may be provided
to permit enlargement of a selected region of a displayed image.
For example, in addition to the illustrated cross-hair
configuration of cursor 14a, cursor 14a may comprise a polygonal
configuration (e.g. a square or rectangular configuration) that may
be positioned to "frame" an enlarged area to be shown in the XZ
ultrasound image.
[0067] In another arrangement, and as shown in FIG. 6B, a projected
XY x-ray image and selected XZ and YZ ultrasound images may be
displayed at the display 14 of the monitoring station 10. Again, a
user may employ the input mouse 13 to select a tissue region of
interest 102, wherein the illustrated crosscut, XZ and ZY plane
images may be automatically displayed. Then, the cursor 14a may be
located on the tissue region of interest 102 on either of the XZ
plane or ZY plane images, wherein input of the cursor position via
mouse 13 may cause an XY plane image (not shown) in the
corresponding Z plane to be generated/displayed via use of the
ultrasound image data. The various displayable images may be
enlarged or otherwise enhanced by processor 16 so as to further
facilitate characterization of the tissue region of interest 102 by
medical personnel.
[0068] Reference will now be made to FIG. 7, which illustrates
general steps of method embodiments comprising the present
invention. As shown, prior to a given imaging procedure, processor
16 may cause radiation signal 26 to be scanned across imaging
assembly 30 together with driven scanning movement of x-ray
detector 40 and ultrasound imager 50. As a result, corresponding
calibration image signals may be provided for subsequent use in
image processing (step 200), as will be noted below.
[0069] For patient screening, a patient breast 100 may be
immobilized (step 201), e.g. the patient breast 100 may be located
in contact relation with the support layer 36 of the imaging
assembly 30. For such proposes, the upper member 21 may be
raised/lowered/rotated as desired. Then, compression member 24 may
be advanced towards the patient breast 100 so as to compress the
patient breast 100 within the predetermined imaging frame of
reference.
[0070] Next, processor 16 may cause a pre-scan to be completed by
scanning radiation signal 26 and x-ray detector 40, wherein the
resultant x-ray image signal may be processed to determine the
location of the edges of the patient breast 100 within the
predetermined imaging frame of reference (step 202). Optionally, a
pre-scan image using ultrasound imager 50 alone may determine the
edge of the breast and the composition of the breast, thus
providing information for optimizing x-ray imaging exposure
parameters. Such breast edge and additional information may be
utilized in conjunction with subsequent imaging steps. For example,
processor 16 may utilize the breast edge information so as to
position the x-ray detector 40 at a location immediately adjacent
to a breast edge for imaging.
[0071] In any case, after the optional pre-scan, the radiation
source 22 and x-ray detector 40 may be controlled so as to scan the
radiation signal 26 and x-ray detector 40 across the patient breast
100 in tandem, thereby obtaining a radiation image signal (step
204). In turn, the radiation image signal may be digitized and the
resultant image data may be processed/stored/displayed at the
monitoring station 10. In conjunction with such processing,
calibration signal data obtained in step 200 may be employed.
[0072] In one embodiment, the method may further include the step
of scanning the ultrasound imager 50 relative to the patient breast
100 (step 206) substantially synchronously with x-ray scanning
(step 204). In turn, the signal may be digitized and the resultant
image data ultrasound image may be processed/stored/displayed at
the monitoring station 10. In conjunction with such processing,
calibration signal data obtained in step 200 may be employed.
[0073] In another embodiment, x-ray imaging and ultrasound imaging
may be completed sequentially. For example, after x-ray imaging
(step 204) the ultrasound imager 50 may be positioned for imaging
operations (step 208). More particularly, the x-ray detector 40 may
be replaced by the ultrasound imager 50. Alternatively, the
ultrasound imager 50 may be displaced from a retracted position to
an advanced position relative to the support layer 36 of housing
32, wherein acoustic coupling means 54 only engages the bottom side
of the support layer 36 when located in the advanced position.
[0074] In any case, once ultrasound imager 50 is properly
positioned, the processor 16 may initiate ultrasound scanning
operations (step 210), wherein the ultrasound imager 50 provides an
ultrasound image signal to the processor 16 for image data storage/
processing/display. Again, in conjunction with such processing,
calibration signal data obtained in step 200 may be employed.
[0075] As shown by FIG. 7, the various methods may also provide for
the selected display of x-ray and ultrasound images (step 212). For
example, and as noted above, such data may be utilized to provide a
projected XY plane image and selected XY, XZ and YZ plane images
corresponding with a tissue region of interest identified by
medical personnel. In turn, such images may be viewed, enhanced,
etc. by medical personnel to characterize the tissue region of
interest.
[0076] The embodiments described above are for exemplary purposes
only and is not intended to limit the scope of the present
invention. Various adaptations, modifications and extensions of the
embodiment will be apparent to those skilled in the art and are
intended to be within the scope of the invention as defined by the
claims which follow.
* * * * *