U.S. patent application number 13/094524 was filed with the patent office on 2012-01-26 for medical emitter/detector imaging/alignment system and method.
Invention is credited to David Chang, Alan Fischer, Andrew G. Fischer, Nicholas Ransom Powley.
Application Number | 20120022357 13/094524 |
Document ID | / |
Family ID | 44904341 |
Filed Date | 2012-01-26 |
United States Patent
Application |
20120022357 |
Kind Code |
A1 |
Chang; David ; et
al. |
January 26, 2012 |
MEDICAL EMITTER/DETECTOR IMAGING/ALIGNMENT SYSTEM AND METHOD
Abstract
Improved methods and apparatuses for imaging during medical
procedures in accordance with various embodiments of the present
invention include use of an image correction algorithm. In various
embodiments, an original image of a region of interest where a
medical procedure occurring along a particular axis will be
performed is created with a beam emitter and a generally planar
detector. Due to the emitter not being aligned orthogonal to the
detector, the original image will be skewed. Using a known location
and orientation of the detector, a location and orientation of the
emitter provided by a position monitoring system, and the original
image, a processing system can execute the image correction
algorithm to provide a corrected image to allow a surgeon to
perform the medical procedure while viewing an accurate corrected
image in real-time.
Inventors: |
Chang; David; (Rochester,
NY) ; Powley; Nicholas Ransom; (St. Paul, MN)
; Fischer; Andrew G.; (Hopkins, MN) ; Fischer;
Alan; (Ames, IA) |
Family ID: |
44904341 |
Appl. No.: |
13/094524 |
Filed: |
April 26, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61328062 |
Apr 26, 2010 |
|
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Current U.S.
Class: |
600/407 ;
378/98.8 |
Current CPC
Class: |
A61B 34/20 20160201;
A61B 6/4452 20130101; A61B 2090/364 20160201; A61B 17/1671
20130101; A61B 6/505 20130101; A61B 8/00 20130101; A61B 90/36
20160201; A61B 6/12 20130101; A61B 6/4405 20130101; A61B 34/10
20160201; A61B 6/022 20130101; A61B 6/587 20130101; A61B 17/1703
20130101; G06T 3/608 20130101; A61B 6/547 20130101; A61B 6/5211
20130101; A61B 5/055 20130101 |
Class at
Publication: |
600/407 ;
378/98.8 |
International
Class: |
A61B 6/00 20060101
A61B006/00; H05G 1/64 20060101 H05G001/64 |
Claims
1. A medical imaging and alignment system for use in performing a
medical procedure on a patient, comprising: a manually positionable
beam emitter adjustable in more than three degrees of freedom, the
emitter including an actuator for performing the medical procedure
along an axis of operation; a generally planar detector that
detects a beam from the emitter, the beam oriented along an axis
parallel to the axis of operation of the actuator, and generates an
original image of a region of interest between the detector and
emitter; a position monitoring system that monitors a position and
an orientation of the emitter in the more than three degrees of
freedom; a processor operably connected to the position monitoring
system and the detector and configured to execute an image
correction algorithm, the image correction algorithm operable to
provide a corrected image from the original image, the original
image of the region of interest skewed when the axis along which
the beam is emitted is at an angle that is not perpendicular to the
detector relative to an actual appearance of the region of interest
from the angle and the corrected image showing the actual
appearance of the region of interest from the angle; and a video
display that displays the corrected image in real-time to a surgeon
performing the medical procedure on the patient.
2. The system of claim 1, wherein the image correction algorithm
operates directly on texture coordinates of the original skewed
image recorded by the detector using matrix transforms.
3. The system of claim 1, wherein the image correction algorithm
utilizes rasterization to provide the corrected image.
4. The system of claim 1, wherein the position monitoring system is
a kinematic or mechanical tracking system.
5. The system of claim 4, wherein the emitter is connected to an
arm of the kinematic or mechanical tracking system.
6. The system of claim 1, wherein the position monitoring system is
an optical tracking system.
7. The system of claim 1, wherein the emitter is manually
positionable in at least 5 degrees of freedom.
8. The system of claim 1, wherein the position monitoring system is
at least partially located within the emitter.
9. The system of claim 1, wherein the actuator is selected from the
group consisting of a drill, a cutting blade and a needle.
10. The system of claim 1, wherein the axis of operation of the
actuator and the axis along which the beam is emitted are
coaxial.
11. The system of claim 10, wherein at least a portion of the
actuator that is coaxial with the axis along which the beam is
emitted is formed of a material that is translucent to the
beam.
12. The system of claim 1, wherein the emitter is an X-ray emitter
and the detector is an X-ray detector.
13. A method comprising: providing a system for performing a
medical procedure on a patient, the system comprising: a manually
positionable beam emitter adjustable in more than three degrees of
freedom, the emitter including an actuator for performing the
medical procedure along an axis of operation; a generally planar
detector that detects the beam from the emitter, the beam oriented
along an axis parallel to the axis of operation of the actuator; a
position monitoring system that monitors a position and an
orientation of the emitter in the more than three degrees of
freedom; a processor operably connected to the position monitoring
system and detector that is configured to execute an image
correction algorithm; and a video display; and providing
instructions for using the system to perform the medical procedure
on the patient, the instructions comprising: manually positioning
the emitter in more than three degrees of freedom and generating an
original image of a region of interest of the patient with the
detector, the emitter being aligned along the axis of operation of
the actuator at an angle that is not perpendicular to the detector
resulting in the original image being skewed relative to an actual
appearance of the region of interest from the angle; viewing a
corrected image of the region of interest on the video display
showing the actual appearance of the region of interest from the
angle, the corrected image resulting from application of the
image-correction algorithm to the skewed original image; and
performing the medical procedure on the patient using the actuator
along the axis of operation while viewing the corrected image on
the imaging system in real-time.
14. The method of claim 13, wherein the step of manually
positioning the emitter includes moving the emitter and an arm of a
kinematic or mechanical tracking system to which the emitter is
attached.
15. The method of claim 13, wherein the step of manually
positioning the emitter in more than three degrees of freedom
includes manually positioning the emitter in at least five degrees
of freedom.
16. The method of claim 13, wherein the emitter is an X-ray emitter
and the detector is an X-ray detector.
17. The method of claim 13, wherein the step of performing the
medical procedure includes inserting a needle that comprises at
least a portion of the actuator into the region of interest.
18. The method of claim 13, wherein the step of performing the
medical procedure includes utilizing a drill assembly that
comprises at least a portion of the actuator to drill into the
region of interest.
19. The method of claim 13, wherein the step of performing the
medical procedure includes resecting a bone with at least a portion
of the actuator.
20. A system for performing a medical procedure on a patient
comprising: means for emitting a beam, the means for emitting being
manually positionable in more than three degrees of freedom and
including a means for performing a medical procedure on a patient
along an axis of operation; means for detecting a beam from the
emitter, the beam emitted along an axis parallel to the axis of
operation of the means for performing a medical procedure, and
generating an original image of a region of interest between the
means for emitting and the means for detecting; means for
generating data representative of the position and orientation of
the means for emitting in the more than three degrees of freedom;
processing means operably connected to the means for detecting and
the means for generating data representative of the position and
orientation of the means for emitting, the processing means
configured to execute a means for providing a corrected image from
the original image, the original image of the region of interest
skewed when the means for emitting is at an angle that is not
perpendicular to the means for detecting relative to an actual
appearance of the region of interest from the angle and the
corrected image showing the actual appearance of the region of
interest; and means for displaying the corrected image in real-time
to a surgeon performing the medical procedure on the patient.
21. The system of claim 20, wherein the means for providing a
corrected image executed by the processing means operates directly
on texture coordinates of the original skewed image detected by the
means for detecting using matrix transforms.
22. The system of claim 20, wherein the means for providing the
corrected image executed by the processing means utilizes
rasterization to provide the corrected image.
23. The system of claim 20, wherein the means for generating data
representative of the position and orientation of the means for
emitting is a kinematic or mechanical tracking system.
24. The system of claim 23, wherein the means for emitting is
connected to an arm of the kinematic or mechanical tracking
system.
25. The system of claim 20, wherein the means for generating data
representative of the position and orientation of the means for
emitting is an optical tracking system.
26. The system of claim 20, wherein the means for generating data
representative of the position and orientation of the means for
emitting is at least partially located within the means for
emitting.
27. The system of claim 20, wherein the means for emitting is
manually positionable in at least five degrees of freedom.
28. The system of claim 20, wherein the axis of operation of the
means for performing the medical procedure and the axis along which
the beam is emitted are coaxial.
29. The system of claim 28, wherein at least a portion of the means
for performing the medical procedure that is coaxial with the axis
along which the beam is emitted is formed of a material that is
translucent to the beam.
30. The system of claim 20, wherein the means for emitting a beam
emits X-rays and the means for detecting a beam detects X-rays.
Description
RELATED APPLICATION
[0001] The present application claims the benefit of U.S.
Provisional Application No. 61/328,062, filed Apr. 26, 2010, the
disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to apparatuses and methods for
imaging while performing medical procedures along a particular
alignment. More specifically, the present invention relates to
imaging systems that allow accurate imaging of a procedure as it is
being performed when an alignment axis of an emitter is not
orthogonal to a planar detector.
BACKGROUND OF THE INVENTION
[0003] Imaging systems are utilized for various applications in the
medical field as well as non-medical applications. For example,
medical imaging systems include general radiological, mammography,
X-ray C-arm, tomosynthesis, ultrasound and computed tomography
imaging systems. These imaging systems, with their different
respective topologies, are used to create images or views of a
region of a patient.
[0004] Modern medical imaging systems have become a valuable tool
in the healthcare profession. Many imaging systems which were once
found only in major medical facilities have become more commonplace
due to their affordable cost and compact size. Mobile imaging
systems are utilized outside of imaging-specific rooms because of
their ability to be transported to operating rooms or other areas
serving multiple purposes, thus providing instant on-the-spot
imaging.
[0005] As a result, real-time imaging is increasingly being
required by medical procedures. For example, many
electro-physiologic cardiac procedures, peripheral vascular
procedures, percutaneous transluminal catheter angioplasty
procedures, urological procedures, and orthopedic procedures
utilize real-time imaging. In addition, modern medical procedures
often require the use of instruments that are inserted into the
human body. These medical procedures often require the ability to
discern the exact location of instruments that are inserted within
the human body, often in conjunction with an accurate image of the
surrounding body through the use of imaging.
[0006] It would be desirable to provide a directed imaging system
designed to replace existing methods for imaging during medical
procedures with a faster and more accurate system in situations
where an alignment axis of an emitter is not orthogonal to a planar
detector.
SUMMARY OF THE INVENTION
[0007] Improved methods and apparatuses for imaging during medical
procedures in accordance with various embodiments of the present
invention include use of an image correction algorithm. In various
embodiments, an original image of a region of interest where a
medical procedure occurring along a particular axis will be
performed is created with a beam emitter and a generally planar
detector. Due to the emitter not being aligned orthogonal to the
detector, the original image will be skewed. Using a known location
and orientation of the detector, a location and orientation of the
emitter provided by a position monitoring system, and the original
image, a processing system can execute the image correction
algorithm to provide a corrected image to allow a surgeon to
perform the medical procedure while viewing an accurate corrected
image in real-time.
[0008] In one embodiment, a system for performing a medical
procedure on a patient utilizes an image correction algorithm. The
system can include a manually positionable beam emitter including
an actuator for performing the medical procedure along a particular
axis. A generally planar detector can detect the beam from the
emitter and generate an original image of a region of interest
between the emitter and detector. A position monitoring system can
monitor a position and orientation of the emitter. A processor
operably connected to the position monitoring system and the
detector can execute an image correction algorithm operable to
provide a corrected image from the original image due to the
original image being skewed as a result of the emitter being
aligned along the axis of operation rather than perpendicular to
the detector. A video display can display the corrected image in
real-time to a surgeon performing the medical procedure on the
patient.
[0009] In another embodiment, a method includes providing a system
for performing a medical procedure on a patient. The system can
include a manually positionable beam emitter including an actuator,
a generally planar detector that detects the beam from the emitter,
a position monitoring system that monitors a position and
orientation of the emitter, a processor that executes an image
correction algorithm and a video display. The method can further
include instructions for performing the medical procedure on the
patient. The instructions can include manually positioning the
emitter in more than three degrees of freedom along an axis of
operation of the actuator at an angle that is not perpendicular to
the detector to obtain an original image of a region of interest,
which results in the original image being skewed. The instructions
further comprise viewing a corrected image of the region of
interest on the video display that results from application of the
image-correction algorithm to the skewed original image and
performing the medical procedure with the actuator while utilizing
the corrected image in real-time to assist during the medical
procedure.
[0010] The above summary of the various embodiments of the
invention is not intended to describe each illustrated embodiment
or every implementation of the invention. This summary represents a
simplified overview of certain aspects of the invention to
facilitate a basic understanding of the invention and is not
intended to identify key or critical elements of the invention or
delineate the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention may be more completely understood in
consideration of the following detailed description of various
embodiments of the invention in connection with the accompanying
drawings, in which:
[0012] FIG. 1 depicts a medical imaging/alignment system according
to an embodiment of the present invention.
[0013] FIG. 2 depicts a medical imaging/alignment system according
to an embodiment of the present invention.
[0014] FIG. 3A depicts an imaging emitter gun according to an
embodiment of the present invention.
[0015] FIG. 3B is a cross-sectional view of the imaging emitter gun
of FIG. 3A, taken at the midplane of the gun looking into the
page.
[0016] FIG. 4 depicts a flowchart of steps of an image correction
algorithm according to an embodiment of the present invention.
[0017] FIG. 5A is a view of an object and original and corrected
images of the object according to an embodiment of the present
invention.
[0018] FIG. 5B is another view of an object and original and
corrected images of the object according to an embodiment of the
present invention.
[0019] FIG. 6 depicts the use of an imaging/alignment system
according to an embodiment of the present invention.
[0020] While the invention is amenable to various modifications and
alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in detail. It should
be understood, however, that the intention is not to limit the
invention to the particular embodiments described. On the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0021] In the following detailed description of the present
invention, numerous specific details are set forth in order to
provide a thorough understanding of the present invention. However,
one skilled in the art will recognize that the present invention
may be practiced without these specific details. In other
instances, well-known methods, procedures, and components have not
been described in detail so as to not unnecessarily obscure aspects
of the present invention.
[0022] Referring to FIG. 1, a schematic representation of a medical
imaging/alignment system 100 according to an embodiment of the
present invention is depicted. System 100 generally includes a beam
emitter 104 and a detector 102 for detecting the beam generated by
emitter 104. Emitter 104, as described more fully herein, can also
incorporate a drill, cutting tool, needle/syringe or other device
for performing a medical operation on a patient. System 100 can
also include a position monitoring system 106 to keep track of or
sense the movements of the emitter 104 in any number of degrees of
freedom. A processor executing a computer-implemented image
correction algorithm 108 can be used, as described more fully
herein, to provide a more accurate image of the imaged region to a
surgeon, who views the corrected image on a monitor or display 110
in real-time.
[0023] The detector 102 is placed beneath/opposite the patient in
the area of interest, i.e., the area where the medical procedure is
performed. In one embodiment, detector 102 is a flat-panel detector
mounted beneath a patient table and on an X/Y movable stage
allowing it to be positioned under the area of interest of the
patient as needed. Such modern flat-panel detectors are
advantageous in that they are light weight, can run high
frame-rates, use fewer parts and can provide an immediate digital
image. Various flat-panel detectors that can be used with
embodiments of the present invention are manufactured by Varian
Medical Systems of Palo Alto, Calif.
[0024] In one embodiment, detector 102 should provide at least near
real-time feedback to the surgeon. In this embodiment, detector 102
can acquire images at a frame rate of at least 15 frames per
second. It has been observed that at rates of higher than 25 frames
per second it is difficult to discern meaningful differences in
detected images as a result of such higher rates, so a range of
frame rates of 15 frames per second to 25 frames per second is
preferred. Ideally, the system 100 uses the largest flat-panel
detector 102 that can provide such a response time in the desired
range of frame rates. In one embodiment, such response times can be
provided by a 16'' by 12'' detector 102.
[0025] The emitter 104 can be a handheld emitter gun that can
include an imaging source located behind an actuator for performing
a medical procedure on a patient. Actuator can include, for
example, a drill bit and drive assembly, a cutting tool or cutting
blade, a needle or syringe or any other device for performing a
medical procedure. In one embodiment, some or all of the elements
of the actuator are translucent to the beam of the imaging source
so as not to interfere with the emitted beam. In this embodiment,
at least the portion of the actuator that is coaxial with an axis
of emission of the emitter is translucent. This provides an
unobstructed image as the procedure is performed, which allows the
surgeon to image the target at the same time as performing the
procedure without the need for a separate device. One embodiment of
an X-ray translucent drill mechanism, aspects of which can be used
in embodiments of the present invention, is disclosed in U.S. Pat.
No. 5,013,317 to Cole et al., which is incorporated herein by
reference. In another embodiment, the imaging source can be aligned
along a parallel axis to the axis of operation of the medical
procedure so that the actuator does not interfere with the emitted
beam while still being aligned at the same angle.
[0026] An emitter 104 in the form of a handheld gun according to an
embodiment of the present invention is depicted in FIGS. 3A and 3B.
Gun 104 is lightweight and easily maneuverable by a surgeon and
includes a handle 115 connected to a housing 116. Housing contains
the actuator 118, which as noted above can be translucent to the
beam, and an imaging source. In one embodiment, the source is
positioned behind the actuator 118 in the housing. In one
embodiment, actuator 118 is a drill mechanism. Drill mechanism 118
can be provided with variously sized interchangeable drill bits 120
to form pilot holes prior to inserting screws. Drill mechanism 118
can also directly insert screws into a desired area. As noted
above, gun 104 can include various other actuators other than drill
mechanism. In some embodiments, gun 104 can be about the size of a
modern cordless drill, allowing the surgeon to move about freely
with the device while performing the procedure. In some
embodiments, the actuator 118 can be interchangeable, such that a
diverse range of procedures can be performed utilizing the same
general system. In one embodiment, this can be done by allowing the
actuator 118 to be removed from the housing 116 and replaced with a
different actuator 118. In another embodiment, a plurality of
emitter/guns 104 can be provided that can be interchanged within
the general system 100, each pre-configured with a different type
of actuator 118 and/or a different type of imaging source. In one
embodiment, the emitter can be provided with a safety feature that
only allows a beam to be emitted when it is aimed at the detector,
to prevent unnecessary and potentially harmful emission of
beams.
[0027] A position monitoring system 106 is used in system 100
because proper visualization of the procedure requires knowing
where the emitter 104 is positioned and oriented in space. In some
embodiments, the detector 102 does not need to be tracked by the
position monitoring system 106 because it maintains a fixed
orientation in space after initially being set for the procedure,
so its location and orientation are known. In other embodiments,
the surgeon can adjust the detector 102 during the procedure, so
the location and orientation of the detector 102 can also be
monitored.
[0028] Position monitoring system 106 must be compatible with the
nearby imaging source, tolerant of significant metal in the
environment, and have high reliability and accuracy. In some
embodiments, position monitoring system 106 can be an optical
tracking system, such as manufactured by Ascension Technology
Corporation of Milton, Vt. In other embodiments, position
monitoring system 106 can be a kinematic/mechanical tracking via an
arm or linkage. In such an embodiment, the emitter/gun can be
attached to a manually positionable arm anchored to a ceiling, wall
or floor of an operating room or a movable base in the operating
room. In other embodiments, position monitoring system can use
radio-frequency identification, image analysis using infrared light
or other wireless tracking/sensing. In some embodiments, some or
all of position monitoring system 106 can be incorporated into
emitter 104 rather than being a separate system. In such
embodiments, position monitoring system 106 can use one or more of
accelerometers, gravitometers, magnetometers, and global
positioning systems to track and/or sense the location and
orientation of emitter 104. Position monitoring system 106 can
allow the emitter to be positionable, and track the positioning of
the emitter, in at least three degrees of freedom. In some
embodiments, the emitter can be positionable in five or six degrees
of freedom. In one embodiment, emitter can be lockable to prevent
movement in one or more degrees of freedom for all or part of the
procedure, such as only allowing the emitter to be moved along the
axis of operation once proper alignment has been obtained.
[0029] Tracking the emitter's 104 location and orientation relative
to the detector 102 and imaged area allows the use of a perspective
image correction algorithm to eliminate the need to keep the gun
104 perpendicular to the detector 102, giving the surgeon a great
deal of freedom of movement in performing the procedure. This is
desirable because often a required axis or alignment of the
procedure relative to the patient's body is not aligned
perpendicular to the detector. If the procedure requires the
emitter 104 to be aligned relative to the patient in a way that
causes it to be at angle to the detector 102, a skewed image is
detected and generated by the detector. Use of an image correction
algorithm allows the surgeon to align the gun 104 at an angle to
the detector 102 that is properly aligned with the patient for
performing the procedure while visualizing an accurate image of the
target area of the patient.
[0030] The image correction algorithm 108 therefore allows the
emitter 104 to be used in alignments that are not orthogonal to the
detector 102 when the emitter 104 is being used to image the area
of interest 112 of a patient on a patient table 114, as depicted in
FIG. 2. The skewed image resulting from non-orthogonal alignment of
the emitter 104 and detector 102 can result in misalignment of the
actuator for the procedure. The image correction algorithm 108
corrects this skewed image so that a true image is shown to the
surgeon in real time, allowing for more accurate use of the gun 104
during the procedure. It should also be noted, as can be seen in
FIG. 2, that the thickness of the table 114 combined with the
thickness of the patient 112 places a geometric limit on the angle
at which the emitter 104 can be used relative to the area of
interest 112 in order to be captured by the detector 102.
[0031] In one embodiment as shown in FIG. 4, the image correction
algorithm 108, which can be executed by a processor, operates
directly on the texture coordinates of the original image recorded
by the detector 102 using matrix transforms. Transform matrices are
a consistent way of representing linear transforms in a
computational format. By representing object locations as vectors,
e.g., f=(x, y, z), those objects may be transformed in space (to f)
by multiplying them with a transform matrix T such that f'=Tf. If
the detector 108 dimensions and it's transform in space D are
known, the location of the four corners of the detector 102 can be
defined with these methods at step 140 in a single 4.times.4 matrix
C, where x1, y1 and z1 (obtained from D and detector 102 geometry)
are a first corner of the detector 102 and so on up to x4, y4 and
z4. The fourth element of each corner's vector represents the scale
of each vector, which may be set to 1.
C = [ x 1 x 2 x 3 x 4 y 1 y 2 y 3 y 4 z 1 z 2 z 3 z 4 1 1 1 1 ]
##EQU00001##
[0032] Standard texture coordinates ranging from 0 to 1 can then be
assigned to the four corner points at step 142. Texture coordinates
(or UV coordinates) are a tool used to linearly map a
two-dimensional image onto a three-dimensional object in space.
These coordinates, usually represented as u and v, are assigned
across an image, ranging from 0 to 1 in each direction. Each vertex
of the three-dimensional object is assigned a u and v coordinate
indicating which part of the two-dimensional image is associated
with that vertex. Since the detector plate is rectangular and is
covered by the detected image, the four corners (or vertices) of
the detector map correspond to the four corners of the detected
image. These four texture coordinates are packed into a texture
matrix T.
T = [ 0 1 1 0 0 0 1 1 ] ##EQU00002##
[0033] By treating the emitter 104 as something of an imaginary
camera, a perspective transformation for the field of view ("fov")
onto the detector 102 can be defined using a standard perspective
transform matrix at step 144. Preferably, the fov is computed to be
just large enough to view the whole detector plate from the
emitter's location. In most applications, a field of view of 45
degrees is sufficient. A perspective transform matrix alters the
shape of a given geometry to match the view of that geometry from a
defined location. It adds perspective to the resulting image, such
as by causing portions of the geometry that are further away to be
smaller. This mimics the view as would be seen by the human eye
from the defined location.
P = [ 1 h 0 0 0 0 1 h 0 0 0 0 ( far + near ) ( near - far ) ( 2 far
near ) ( near - far ) 0 0 - 1 0 ] ##EQU00003##
[0034] Where h=tan(fov/2) and far and near are the distances to the
far and near view planes. For optimal viewing, near is set at 1 and
far is the distance between the emitter 104 and the furthest corner
of the detector 102. Next, the gun/emitter transform matrix G
(obtained from the position monitoring system) can be used to bring
the detector 102 corners into the image of the imaginary camera,
C*, at step 146.
C*=PGC
[0035] Finally, the corrected image is obtained at step 148 by
rasterizing the image space corners C* as a quadrilateral textured
with the original detector image, by interpolating according to the
texture coordinates. Rasterization is a standard computer graphics
algorithm, which is known to those skilled in the art.
Rasterization, also known as scan conversion, is the process of
rendering a three-dimensional shape or scene onto a flat
two-dimensional surface, usually so it can be viewed on a monitor.
Rasterization is used as part of the image correction algorithm 108
to render the transformed detector plate object (textured with its
detected image) into the view space of the imaginary camera located
at the gun/emitter. This yields the corrected image. In one
embodiment, the image correction algorithm is performed by a
desktop or laptop computer. In other embodiments, the algorithm can
be performed by a processor within the emitter 104 or detector 102
or associated with the monitor or display 110. In one embodiment,
the algorithm continuously runs during the operation to provide a
continuous real-time corrected image that continually adjusts for
movements of the emitter 104, detector 102 or region of interest to
show the actual appearance of the region in real-time.
CorrectedImage=Rasterize(C*,T,OriginalImage)
[0036] By defining the field of view and near/far planes as
described herein, a minimum of information is lost during the image
correction process. No scaling is required to obtain a properly
sized corrected image. The entire process can also be implemented
using modern graphics hardware. Corrected images can therefore be
processed at extremely high frame rates on the order of hundreds of
times per second even for large images.
[0037] FIGS. 5A and 5B depict results of such image corrections. In
FIG. 5A, a cylindrical object 130 is being viewed with the beam
emitter 104 along the vertical axis of the object. On the left the
original image 132 result as initially detected by the detector 102
is displayed. Because of the angle between the emitter 104 and the
detector 102, the image 132 is skewed. The corrected image 134 as
displayed on a monitor 110 following application of the image
correction algorithm 108 described herein to the image 132 recorded
at the detector, which as can be seen is identical to the actual
image 130, is displayed on the right. FIG. 5B depicts a view of a
cylindrical object 130 from an oblique angle with the emitter 104.
Similarly, the original image 136 as detected by the detector 102
is skewed, whereas the corrected image 138 displays the actual
appearance of the object 130 from the oblique angle.
[0038] Referring now to FIG. 6, there can seen the result of such
an image correction during a procedure being performed on a patient
113 on a patient table 114 according to an embodiment of the
present invention. The view in the Figure is taken down the
emitting axis of an emitter at an angle to the detector. The
original skewed image 152 generated by the detector is corrected
with the processor operating the image-correction algorithm and is
displayed as a corrected image 154 that shows the actual appearance
150 of the patient's spine from the angle on the monitor 110.
[0039] The monitor 110 need only be safe for use in an operating
room and large enough to be easily observed by a surgeon while
performing an operation. The monitor must be sterile if located
within the sterile field of the procedure. If the monitor is not
within the sterile field, it will not have to be sterile but will
have to be larger than a monitor within the sterile field in order
to be viewable from within the sterile field. In one embodiment,
the display can be part of the emitter gun, such as a video screen
located on a proximal end of the gun.
[0040] Beam emitter 104 and detector 102 can incorporate various
imaging systems that can be employed in embodiments of the above
described system 100. Beam emitter 104 and detector 102 can relate
to any type of imaging system that emits a beam that is captured by
a detector to generate an image. In one embodiment, imaging system
is an X-ray imaging system with an emitter 104 including an X-ray
source having an X-ray tube having an anode, a cathode and a power
source, and an X-ray detector. In another embodiment, imaging
system is a terahertz imaging system having a source emitting
electromagnetic waves in the terahertz range and a cooperating
detector. In a further embodiment, the source can provide
ultrasonic waves for an ultrasound-based imaging system. In another
embodiment, system can utilize magnetic resonance imaging, wherein
the magnetic source is located inside the emitter gun.
[0041] Imaging and alignment systems as described herein can be
used with a number of medical procedures. Various procedures that
can advantageously utilize such a system will be described below.
However, the procedures described herein are illustrative and are
not limiting. System can be used with any medical procedure that
would benefit from the use of imaging. In addition,
imaging/alignment systems as described herein can be employed in
non-medical applications. System can be utilized in any non-medical
application that utilizes imaging, such as, for example, airport
screening. In such embodiments, system can optionally be provided
with various safety features to prevent human exposure to the beam,
such as not allowing the emitter to emit a beam when it is not
aimed at the detector and ceasing emission if it is detected that
human tissue or bone is within the imaging field. In one
embodiment, image recognition can be employed to detect whether
safety features should be invoked.
[0042] In one embodiment, imaging system is used to insert pedicle
screws into a spine of a patient. Emitter gun can be equipped with
a drill bit and drive assembly for inserting the screws into the
pedicle and optionally drilling pilot holes into the pedicles prior
to insertion. In pedicle screw insertion, it is key to align the
screws axially down the pedicle. However, the pedicles are often
not aligned perpendicular to the detector and each pedicle may have
a different alignment. Use of imaging system allows an accurate
image of each pedicle to allow the screws to be properly placed
axially along the pedicles.
[0043] In another embodiment, imaging system can be used to aid in
performing needle biopsies. The actuator in such a system can be be
a needle, which can be translucent. Imaging system allows the
surgeon to view an accurate real-time image of where the needle is
positioned to ensure that the biopsy is taken in the proper area.
In one embodiment, the biopsy procedure can be a bone biopsy.
[0044] In a further embodiment, imaging system can assist
vertebroplasty and kyphoplasty procedures. Vertebroplasty uses a
hollow needle to inject bone cement into fractured, crushed or
otherwise weakened vertebrae to provide support and treat pain. In
kyphoplasty, a balloon is first inserted into the area through a
needle and expanded in the fracture and then bone cement is
inserted into the balloon with the needle. Imaging system can be
used to properly guide the process with a needle as the actuator
for inserting the bone cement and/or balloon.
[0045] A number of bones in the body can have fractures repaired
using intramedullary rods. A hole is drilled down the long axis of
the bone and a rod is then driven into the cavity to align the
bones and promote healing. The rods can then be locked by drilling
screws orthogonally into the rod to prevent collapse or rotation.
An imaging system as described herein can aid in proper alignment
and placement of one or more of the rod or the locking screws.
[0046] In another embodiment, imaging system can be used with a
pelvic fixation procedure. Pelvic fixation is a difficult procedure
involving the placement of plates and/or screws to hold together
portions of a fractured pelvis. The enhanced imaging of imaging
system could be advantageously used to drill holes in the proper
locations and insert the screws to ensure that the screws properly
engage the complicated structure of the pelvic bones.
[0047] In a further embodiment, imaging system can be used to aid
in resecting bones, such as knee bones. Emitter could be equipped
with a saw blade, milling tool, or other device for removing bone.
The system could then be used to enhance the visualization of a
minimally invasive procedure to ensure that the bone is resected at
the proper angle and depth.
[0048] In one embodiment, a second emitter and detector plate can
be utilized in the system, which can be positioned at a known
offset from those already present in the system. By using this
second imaging set to image the same target area, a
three-dimensional stereoscopic image of the procedure can be
generated. Such an imaging system can provide a sense of depth to
the procedure that can allow a surgeon to see, for example, how far
a drill has penetrated into a bone or how far a biopsy needle has
been inserted. In one embodiment, the separate emitter and detector
can be provided by a traditional c-arm device. Alternatively, the
second emitter can be a second manually positionable detector as
described herein.
[0049] In another embodiment, structured infrared light combined
with computer scanning can be incorporated into system to provide a
topological view of the body's surface. This technology can be
incorporated into the emitter gun to produce a combined image that
shows transparent surface detail overlaid onto the image of the
underlying bone. This also can be used to provide a sense of drill,
needle, or other actuator depth to the surgeon.
[0050] In a further embodiment, a dye injection or spatter
mechanism can be integrated with the emitter gun. The surgeon can
then use the gun to inject radiopaque dye ahead of the actuator,
allowing a clearer image of the target area where the operation is
performed. In one embodiment, this procedure can be used in a
target area having soft-tissue that does not normally image well
under imaging beam, such as in various biopsy types.
[0051] Various embodiments of systems, devices and methods have
been described herein. These embodiments are given only by way of
example and are not intended to limit the scope of the present
invention. It should be appreciated, moreover, that the various
features of the embodiments that have been described may be
combined in various ways to produce numerous additional
embodiments. Moreover, while various materials, dimensions, shapes,
implantation locations, etc. have been described for use with
disclosed embodiments, others besides those disclosed may be
utilized without exceeding the scope of the invention.
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