U.S. patent application number 12/763231 was filed with the patent office on 2010-09-02 for apparatus and method for multi-modal imaging.
Invention is credited to Gilbert D. Feke, William E. McLaughlin, Douglas L. Vizard.
Application Number | 20100220836 12/763231 |
Document ID | / |
Family ID | 42667079 |
Filed Date | 2010-09-02 |
United States Patent
Application |
20100220836 |
Kind Code |
A1 |
Feke; Gilbert D. ; et
al. |
September 2, 2010 |
APPARATUS AND METHOD FOR MULTI-MODAL IMAGING
Abstract
An imaging system and method for imaging an immobilized object.
The imaging system includes a support member adapted to receive the
object in an immobilized state. The system also includes first
means for imaging the immobilized object in a first imaging mode to
capture a first image, and second means for imaging the immobilized
object in a second imaging mode to capture a second image. The
first imaging mode is selected from the group: x-ray mode and radio
isotopic mode. The second imaging mode is selected from the group:
bright-field mode and dark-field mode. The first and second means
for imaging may be included in a capture system having a camera, a
first mirror on a first side of the support member for reflecting
light to capture the first and second images and a second mirror on
a second, opposite side of the support member for reflecting light
to capture a third image from an opposite side of the object. A
movable phosphor screen is employed when the first image is
captured and not employed when the second image is captured. The
phosphor screen is adapted to be movable without moving the
immobilized object and support member. The system can further
include means for generating a third image comprised of the first
and second images.
Inventors: |
Feke; Gilbert D.; (Durham,
CT) ; McLaughlin; William E.; (Guilford, CT) ;
Vizard; Douglas L.; (Durham, CT) |
Correspondence
Address: |
Carestream Health, Inc.;ATTN: Patent Legal Staff
150 Verona Street
Rochester
NY
14608
US
|
Family ID: |
42667079 |
Appl. No.: |
12/763231 |
Filed: |
April 20, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11221530 |
Sep 8, 2005 |
7734325 |
|
|
12763231 |
|
|
|
|
12196300 |
Aug 22, 2008 |
|
|
|
11221530 |
|
|
|
|
12354830 |
Jan 16, 2009 |
|
|
|
12196300 |
|
|
|
|
12381599 |
Mar 13, 2009 |
|
|
|
12354830 |
|
|
|
|
12475623 |
Jun 1, 2009 |
|
|
|
12381599 |
|
|
|
|
Current U.S.
Class: |
378/62 ;
348/207.1; 348/E5.024; 382/132 |
Current CPC
Class: |
A61B 5/0071 20130101;
A61B 5/0059 20130101; A61B 2562/17 20170801; A61B 6/4417 20130101;
A61B 6/5247 20130101; A61B 5/0035 20130101; A61B 6/00 20130101 |
Class at
Publication: |
378/62 ;
348/207.1; 382/132; 348/E05.024 |
International
Class: |
G01N 23/04 20060101
G01N023/04; H04N 5/225 20060101 H04N005/225; G06K 9/00 20060101
G06K009/00 |
Claims
1. An imaging system for imaging an object, comprising: a support
member adapted to receive the object in an immobilized state, the
support member including a frame supporting an optically clear
support element for the object; an imaging unit: for imaging the
immobilized object in a first imaging mode to capture a first
image, the first imaging mode being selected from the group
consisting of x-ray mode and radio isotope mode; and for imaging
the immobilized object in a second imaging mode that uses light
from the immobilized object, different from the first imaging mode,
to capture a second image, the second imaging mode being selected
from the group consisting of: bright-field mode, fluorescence mode,
and luminescence mode; a movable phosphor plate to transduce
ionizing radiation to visible light, the phosphor plate being
mounted to be moved, without moving the immobilized object and the
support member, between: a first position proximate the support
member for and during capture of the first image; and a second
position not proximate the support member during capture of the
second image; a protective layer on the phosphor plate to protect a
surface of the phosphor plate facing the support element of the
support member during movement of the phosphor plate between the
first and second positions; and a capture system for capturing
either the first image or the second image of the object.
2. The imaging system of claim 1, wherein the support element is a
sheet of plastic stretched on the frame.
3. The imaging system of claim 1, wherein the protective layer is
reflective.
4. The imaging system of claim 1, wherein the capture system
comprises a camera to capture the first and second images and a
computer with a display for the images.
5. The imaging system of claim 1, further comprising a light-tight
sample environment for the support member to provide life support
for the object.
6. The imaging system of claim 1, further comprising an image
merging unit for generating a third image by merging the first and
second images.
7. The imaging system of claim 1, further comprising multiple
optical elements to enable the location of a common focal plane
shared by the first and second imaging modes.
8. An imaging system for imaging an object, comprising: a support
member adapted to receive the object in an immobilized state; an
imaging unit: for imaging the immobilized object in a first imaging
mode to capture a first image, the first imaging mode being
selected from the group consisting of: x-ray imaging mode and
isotope imaging mode; and for imaging the immobilized object in a
second imaging mode that uses light from the object to capture a
second image, the second imaging mode being selected from the group
consisting of: bright-field imaging mode and dark-field imaging
mode; a movable phosphor plate mounted to be disposed in a first
position proximate the support member when capturing the first
image; means for removing the phosphor plate from the first
position proximate the support member, after capturing the first
image and without moving the immobilized object and the support
member, and for moving the phosphor plate to a second position not
proximate the support member prior to capturing the second image;
and a capture system for capturing either the first image or the
second image of the object, the capture system comprising a camera,
a first mirror on a first side of the support member for reflecting
to the camera light from the object or from the phosphor plate to
capture the first and second images; and a second mirror on a
second, opposite side of the support member for reflecting to the
camera light to capture a third image from an opposite side of the
object than that of the second image.
9. The imaging system of claim 8, wherein the capture system
further comprises a computer for receiving data from the camera and
generating a fourth image by merging the first and second images
and a fifth image by merging the first and third images.
10. The imaging system of claim 8, further comprising an image
merging unit for generating a fourth image by merging the first and
second images.
11. The imaging system of claim 8, further comprising multiple
optical elements to enable the location of a common focal plane
shared by the first and second imaging modes.
12. A method of imaging an object, comprising the steps of:
providing a support member adapted to receive the object in an
immobilized state; placing the object on the support member in an
immobilized state; providing a phosphor plate adapted to be
disposed proximate the support member when capturing a first image;
disposing the phosphor plate proximate the support member; imaging
the immobilized object in a first imaging mode to capture the first
image, the first imaging mode being selected from the group
consisting of: x-ray mode and radio isotope mode; removing the
phosphor plate from proximate the support member, after capturing
the first image and without moving the immobilized object and the
support member; with the phosphor plate removed from proximate the
support member, imaging the immobilized object in a second imaging
mode that uses light from the object to capture a second image, the
second imaging mode being selected from the group consisting of:
bright-field mode and dark-field mode; and imaging the immobilized
object in the second imaging mode, but from a side of the object
opposite that used when capturing the second image, to capture a
third image.
13. The method of claim 12, further comprising the step of
generating a fourth image by merging the first and second images
and a fifth image by merging the first and third images.
14. A method of imaging an object, comprising the steps of:
providing a support member adapted to receive the object in an
immobilized state; placing the object on the support member in an
immobilized state; providing a phosphor plate movable relative to
the support member, without moving the immobilized object and the
support member, between a first position wherein the phosphor plate
is in optical registration with the support member and a second
position wherein the phosphor plate is not in optical registration
with the support member; disposing the phosphor plate in the first
position; capturing a first, x-ray image or a first, radio isotopic
image of the immobilized object when the phosphor plate is disposed
in the first position; moving the phosphor plate to the second
position; using light from the object, capturing a second,
dark-field image or a second, bright-field image of the immobilized
object when the phosphor plate is disposed in the second position;
and using light from the object, capturing a third, dark-field
image or a third, bright-field image of the immobilized object from
a side of the object opposite that used during capture of the
second, dark-field image or the second, bright-field image.
15. The method of claim 14, further comprising the steps of:
generating a third image by merging the first and second images;
generating a fourth image by merging the first and third images;
and displaying, transmitting, processing, or printing, the third
and fourth merged images.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of the following
commonly assigned, copending U.S. patent Applications, each of
which is incorporated by reference into this specification:
[0002] U.S. Ser. No. 11/221,530 filed Sep. 9, 2005 by Vizard et al,
entitled APPARATUS AND METHOD FOR MULTI-MODAL IMAGING, published as
US 2006/0064000;
[0003] U.S. Ser. No. 12/196,300 filed Aug. 22, 2008 by Harder et
al, entitled APPARATUS AND METHOD FOR MULTI-MODAL IMAGING USING
NANOPARTICLE MULTI-MODAL IMAGING PROBES, published as US
2009/0086908;
[0004] U.S. Ser. No. 12/354,830 filed Jan. 16, 2009 by Feke et al,
entitled APPARATUS AND METHOD FOR MULTI-MODAL IMAGING, published as
US 2009/0159805;
[0005] U.S. Ser. No. 12/381,599 filed Mar. 13, 2009 by Feke et al,
entitled METHOD FOR REPRODUCING THE SPATIAL ORIENTATION OF AN
IMMOBILIZED SUBJECT IN A MULTI-MODAL IMAGING SYSTEM, published as
US 2009/0238434; and
[0006] U.S. Ser. No. 12/475,623 filed Jun. 1, 2009 by Feke et al,
entitled TORSIONAL SUPPORT APPARATUS AND METHOD FOR CRANIOCAUDAL
ROTATION OF ANIMALS, published as US 2010/0022866.
FIELD OF THE INVENTION
[0007] The invention relates generally to the field of imaging
systems, and more particularly to the imaging of objects. More
specifically, the invention relates to an apparatus and method that
enable analytical imaging of objects (for example, small animals
and tissue) in differing modes, including bright-field, dark-field
(e.g., luminescence and fluorescence), and x-ray and radioactive
isotopes.
differing modes, including bright-field, dark-field (e.g.,
luminescence and fluorescence), and x-ray and radioactive
isotopes.
BACKGROUND OF THE INVENTION
[0008] Electronic imaging systems are well known for enabling
molecular imaging. An exemplary electronic imaging system (shown in
FIG. 1 and diagrammatically illustrated in FIG. 2) is the Image
Station 2000MM Multimodal Imaging System 10 available from the
Eastman Kodak Company. System 10 includes a light source 12, an
optical compartment 14 which can include a mirror 16, a lens/camera
system 18, and a communication/computer control system 20 which can
include a display device, for example, a computer monitor 22.
Camera/lens system 18 can include an emission filter wheel for
fluorescent imaging. Light source 12 can include an excitation
filter selector for fluorescent excitation or bright field color
imaging. In operation, an image of an object is captured using
lens/camera system 18. System 18 converts the light image into an
electronic image, which can be digitized. The digitized image can
be displayed on the display device, stored in memory, transmitted
to a remote location, processed to enhance the image, and/or used
to print a permanent copy of the image.
[0009] Applicants have recognized a need for an apparatus and
method for enabling analytical imaging of an object in differing
modes.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide an
apparatus and method for enabling analytical imaging of an
object.
[0011] Another object of the present invention is to provide such
an apparatus and method for enabling analytical imaging of an
object in differing modes.
[0012] These objects are given only by way of illustrative example,
and such objects may be exemplary of one or more embodiments of the
invention. Other desirable objectives and advantages inherently
achieved by the disclosed invention may occur or become apparent to
those skilled in the art. The invention is defined by the appended
claims.
[0013] One embodiment of the invention concerns an imaging system
for imaging an immobilized object. The system includes a support
member adapted to receive the object in an immobilized state, the
support member including a frame supporting an optically clear
support element for the object. An imaging unit is included for
imaging the immobilized object in a first imaging mode to capture a
first image, the first imaging mode being selected from the group
consisting of: x-ray mode and radio isotope mode; and for imaging
the immobilized object in a second imaging mode that uses light
from the immobilized object, different from the first imaging mode,
to capture a second image, the second imaging mode being selected
from the group consisting of: bright-field mode, fluorescence mode,
and luminescence mode. A movable phosphor plate is included to
transduce ionizing radiation to visible light. The phosphor plate
is mounted to be moved, without moving the immobilized object and
the support member, between a first position proximate the support
member for and during capture of the first image and a second
position not proximate the support member during capture of the
second image. A layer on the phosphor plate protects a surface of
the phosphor plate facing the support element of the support member
during movement of the phosphor plate between the first and second
positions. A capture system is included for capturing either the
first image or the second image of the object.
[0014] Another embodiment of the invention also concerns an imaging
system for imaging an immobilized object. A support member is
adapted to receive the object in an immobilized state. An imaging
unit is included for imaging the immobilized object in a first
imaging mode to capture a first image, the first imaging mode being
selected from the group consisting of x-ray imaging mode and
isotope imaging mode; and for imaging the immobilized object in a
second imaging mode that uses light from the object to capture a
second image, the second imaging mode being selected from the group
consisting of bright-field imaging mode and dark-field imaging
mode. A movable phosphor plate is mounted to be disposed in a first
position proximate the support member when capturing the first
image. A moving unit is provided for removing the phosphor plate
from the first position proximate the support member, after
capturing the first image and without moving the immobilized object
and the support member, and for moving the phosphor plate to a
second position not proximate the support member prior to capturing
the second image. A capture system is provided for capturing either
the first image or the second image of the object, the capture
system comprising a camera, a first mirror on a first side of the
support member for reflecting to the camera light from the object
or from the phosphor plate to capture the first and second images;
and a second mirror on a second, opposite side of the support
member for reflecting to the camera light to capture a third image
from an opposite side of the object than that of the second
image.
[0015] Yet another embodiment of the invention concerns a method of
imaging an immobilized object. The method includes steps of
providing a support member adapted to receive the object in an
immobilized state; placing the object on the support member in an
immobilized state; providing a phosphor plate adapted to be
disposed proximate the support member when capturing a first image;
disposing the phosphor plate proximate the support member; imaging
the immobilized object in a first imaging mode to capture the first
image, the first imaging mode being selected from the group
consisting of: x-ray mode and radio isotope mode; removing the
phosphor plate from proximate the support member, after capturing
the first image and without moving the immobilized object and the
support member; with the phosphor plate removed from proximate the
support member, imaging the immobilized object in a second imaging
mode that uses light from the object to capture a second image, the
second imaging mode being selected from the group consisting of:
bright-field mode and dark-field mode; and imaging the immobilized
object in the second imaging mode, but from a side of the object
opposite that used when capturing the second image, to capture a
third image.
[0016] A further embodiment of the invention also concerns a method
of imaging an immobilized object. The method includes steps of
providing a support member adapted to receive the object in an
immobilized state; placing the object on the support member in an
immobilized state; providing a phosphor plate movable relative to
the support member, without moving the immobilized object and the
support member, between a first position wherein the phosphor plate
is in optical registration with the support member and a second
position wherein the phosphor plate is not in optical registration
with the support member; disposing the phosphor plate in the first
position; capturing a first, x-ray image or a first, radio isotopic
image of the immobilized object when the phosphor plate is disposed
in the first position; moving the phosphor plate to the second
position; using light from the object, capturing a second,
dark-field image or a second, bright-field image of the immobilized
object when the phosphor plate is disposed in the second position;
and using light from the object, capturing a third, dark-field
image or a third, bright-field image of the immobilized object from
a side of the object opposite that used during capture of the
second, dark-field image or the second, bright-field image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
description of the embodiments of the invention, as illustrated in
the accompanying drawings. The elements of the drawings are not
necessarily to scale relative to each other.
[0018] FIG. 1 shows a perspective view of an exemplary prior art
electronic imaging system.
[0019] FIG. 2 shows a diagrammatic view of the prior art electronic
imaging system of FIG. 1.
[0020] FIG. 3A shows a diagrammatic side view of the imaging system
in accordance with the present invention.
[0021] FIG. 3B shows a diagrammatic front view of the imaging
system of FIG. 3A.
[0022] FIG. 4 shows a perspective view of the imaging system of
FIGS. 3A and 3B.
[0023] FIG. 5A shows a diagrammatic side view of the sample object
stage.
[0024] FIG. 5B shows a diagrammatic side view of the sample object
stage in the first imaging position P1 wherein the phosphor plate
is disposed proximate the sample object stage.
[0025] FIG. 5C shows a diagrammatic side view of the sample object
stage in the second imaging position P2 wherein the phosphor plate
is not proximate the sample object stage.
[0026] FIG. 6 shows an enlarged, fragmentary sectional view taken
along line 6-6 of FIG. 5B.
[0027] FIG. 7 shows an enlarged, fragmentary sectional view taken
along line 7-7 of FIG. 5C.
[0028] FIG. 8 shows a work flow diagram in accordance with a method
of the present invention.
[0029] FIG. 9A shows a first image of an immobilized object in a
first imaging mode.
[0030] FIG. 9B shows a second image of the immobilized object of
FIG. 9A in a second imaging mode.
[0031] FIG. 9C shows an image generated by the merger of the images
of FIGS. 9A and 9B.
[0032] FIG. 10A shows a first image of an immobilized object in a
first imaging mode.
[0033] FIG. 10B shows a second image of the immobilized object of
FIG. 10A in a second imaging mode.
[0034] FIG. 10C shows an image generated by the merger of the
images of FIGS. 10A and 10B.
[0035] FIG. 11A shows a first image of an immobilized object in a
first imaging mode.
[0036] FIG. 11B shows a second image of the immobilized object of
FIG. 11A in a second imaging mode.
[0037] FIG. 11C shows an image generated by the merger of the
images of FIGS. 11A and 11B.
[0038] FIG. 12 is a diagrammatic view of a suitable phosphor plate
for use with the apparatus and method of the present invention.
[0039] FIG. 13 is a flow diagram of a method for making a phosphor
plate of FIG. 12.
[0040] FIG. 14 illustrates schematically how an image captured
using the configuration of FIG. 5C can be merged or co-registered
with an image captured using the configuration of FIG. 5B.
[0041] FIG. 15A illustrates schematically a system for capturing
visible light images from both sides on an immobilized object.
[0042] FIG. 15B illustrates schematically how the system of FIG.
15A may be used for capturing an x-ray image from one side of an
immobilized object.
[0043] FIG. 15C illustrates how optical images captured as in FIG.
15A may be merged or co-registered with x-ray images captured as in
FIG. 15B.
DETAILED DESCRIPTION OF THE INVENTION
[0044] The following is a detailed description of the preferred
embodiments of the invention, reference being made to the drawings
in which the same reference numerals identify the same elements of
structure in each of the several figures.
[0045] Applicants have recognized that the complex pharmaceutical
analyses of small objects/subjects (e.g., small animal and tissue)
images are particularly enhanced by using different in-vivo imaging
modalities. Using the known/current practices of bright-field,
dark-field and radiographic imaging for the analysis of small
objects/subjects (such as a mouse) can be expensive and may not
provide the precision of co-registered images that is desired.
[0046] Using the apparatus and method of the present invention,
precisely co-registered fluorescent, luminescent and/or isotopic
probes within an object (e.g., a live animal and tissue) can be
localized and multiple images can be accurately overlaid onto the
simple bright-field reflected image or anatomical x-ray of the same
animal within minutes of animal immobilization.
[0047] The present invention uses the same imaging system to
capture differing modes of imaging, thereby enabling/simplifying
multi-modal imaging. In addition, the relative movement of probes
can be kinetically resolved over the time period that the animal is
effectively immobilized (which can be tens of minutes).
Alternatively, the same animal may be subject to repeated complete
image analysis over a period of days/weeks required to assure
completion of a pharmaceutical study, with the assurance that the
precise anatomical frame of reference (particularly, the x-ray) may
be readily reproduced upon repositioning the object animal. The
method of the present invention can be applied to other objects
and/or complex systems subject to simple planar imaging
methodologies.
[0048] More particularly, using the imaging system of the present
invention, an immobilized object can be imaged in several imaging
modes without changing/moving the immobilized object. These
acquired multi-modal images can then be merged to provide one or
more co-registered images for analysis.
[0049] Imaging modes supported by the apparatus/method of the
present invention include: x-ray imaging, bright-field imaging,
dark-field imaging (including luminescence imaging, fluorescence
imaging) and radioactive isotope imaging. Images acquired in these
modes can be merged in various combinations for analysis. For
example, an x-ray image of the object can be merged with a near IR
fluorescence image of the object to provide a new image for
analysis.
[0050] The apparatus of the present invention is now described with
reference to FIGS. 3A, 3B, and 4. FIG. 3A shows a diagrammatic side
view of an imaging system 100 in accordance with the present
invention, FIG. 3B shows a diagrammatic front view of imaging
system 100, and FIG. 4 shows a perspective view of imaging system
100.
[0051] Imaging system 100 includes light source 12, optical
compartment 14, a lens/camera system 18, and communication/computer
control system 20 which can include a display device, for example,
a computer monitor 22. Camera/lens system 18 can include an
emission filter wheel for fluorescent imaging. Light source 12 can
include an excitation filter selector for fluorescent excitation or
bright field color imaging.
[0052] As best shown in FIG. 3A, imaging system 100 includes an
x-ray source 102 and a support member such as a sample object stage
104. An immobilized object such as a mouse is received on and
supported by sample object stage 104 during operation of system 100
Imaging system 100 further comprises epi-illumination, for example,
using fiber optics 106, which directs conditioned light (of
appropriate wavelength and divergence) toward sample object stage
104 to provide bright-field or fluorescent imaging.
[0053] Sample object stage 104 is disposed within a sample
environment 108, which allows access to the object being imaged.
Preferably, sample environment 108 is light-tight and fitted with
light-locked gas ports (not illustrated) for environmental control.
Environmental control enables practical x-ray contrast below 8 Kev
(air absorption) and aids in life support for biological specimens.
Such environmental control might be desirable for controlled x-ray
imaging or for support of particular specimens.
[0054] Imaging system 100 can include an access means/member 110 to
provide convenient, safe and light-tight access to sample
environment 108, such as a door, opening, labyrinth, and the like.
Additionally, sample environment 108 is preferably adapted to
provide atmospheric control for sample maintenance or soft x-ray
transmission (e.g., temperature/humidity/alternative gases and the
like).
[0055] Imaging system 100 can be a unitary system. Alternatively,
imaging system 100 can be a modular unit adapted to be used/mated
with electronic imaging system such as electronic imaging system
10.
[0056] FIGS. 5-7 more particularly illustrate elements of sample
object stage 104 and an optical interface relative with the focal
plane of camera/lens system 18. FIG. 5A shows a diagrammatic side
view of sample object stage 104 showing the relative movement of a
movable phosphor plate 125 according to the invention relative to
the sample object stage. FIG. 5B shows a diagrammatic side view of
the sample object stage in a first imaging position P1 wherein the
phosphor plate 125 is disposed proximate the sample object stage
and positioned for imaging light from a phosphor layer 130, shown
in FIG. 6. FIG. 5C shows a diagrammatic side view of the sample
object stage in the second imaging position P2 wherein phosphor
plate 125 has been withdrawn to a position that is not proximate
the sample object stage. FIG. 6 shows an enlarged, fragmentary
sectional view taken along line 6-6 of FIG. 5B, which corresponds
with the first imaging position P1. FIG. 7 shows an enlarged,
fragmentary sectional view taken along line 7-7 of FIG. 5C, which
corresponds with the second imaging position P2.
[0057] Continuing with regard to FIGS. 6 and 7, sample object stage
104 includes a support member made up from an open frame 120 to
support and stretch a thin plastic support sheet 122. Support sheet
122 is selected so as to support the weight of a sample or object
to be imaged and is made from a material that is optically clear
and free of significant interfering fluorescence.
[0058] Phosphor plate 125 is mounted for motion toward and away
from sample object stage 104. While those skilled in the art might
recognize other configurations, in a preferred embodiment, phosphor
plate 125 is mounted for translation to provide slidable motion (in
the direction of arrow A in FIG. 5A) relative to frame 120, beneath
the sample, in intimate contact with support sheet 122. Such motion
can be accomplished using methods known to those skilled in the
art, for example, frame 100 and phosphor plate 125 can be disposed
on rails supported by a surface of an optical platen 126. As will
be more particularly described below, in a first imaging position
P1, phosphor layer 130 in phosphor plate 125 is in overlapping
arrangement with sample object stage 104 (FIG. 6) when an x-ray
image of the object is captured. In second imaging position P2,
phosphor plate 125 is translated/moved away from sample object
stage 104 (FIG. 7) for capture of an image of the object such that
phosphor plate 125 is not imaged when an image of the object is
captured in second imaging position P2.
[0059] FIG. 6 provides an enlarged view of sample object stage 104
including phosphor plate 125 to more particularly show a focal
plane. Sample support sheet 122 preferably comprises Mylar or
polycarbonate and has a nominal thickness of about 0.1 mm. A
protective layer 128 (for example, reflective Mylar) of about 0.025
mm is provided to protect the phosphor surface of phosphor plate
125. Protective layer 128 promotes/increases the image-forming
light output. In a preferred embodiment, protective layer 128 is
reflective so as to prevent object reflection back into the
image-forming screen, reducing the confusing the ionizing radiation
image.
[0060] Phosphor layer 130 functions to transduce ionizing radiation
to visible light that can be practically managed by lens and camera
system 18 (such as a CCD camera). Phosphor layer 130 can have a
thickness ranging from about 0.01 mm to about 0.1 mm, depending
upon the application (i.e., soft x-ray, gamma-ray or fast electron
imaging). On the underside of phosphor layer 130, as illustrated,
an optical layer 132 is provided for conditioning emitted light
from phosphor layer 130. Optical layer 132 can have a thickness in
the range of less than about 0.001 mm. Particular information about
phosphor layer 130 and optical layer 132 are disclosed in U.S. Pat.
No. 6,444,988 (Vizard), commonly assigned and incorporated herein
by reference. A supporting glass plate 134 is provided. Glass plate
134 is spaced at a suitable mechanical clearance from an optical
platen 126, for example, by an air gap/void 136. In the preferred
embodiment, the surfaces of clear optical media (e.g., a lower
surface of glass plate 134 and both surfaces of optical platen 126)
are provided with an anti-reflective coating to minimize
reflections that may confuse the image of the object.
[0061] FIG. 7 provides an expanded view of sample object stage 104
including wherein phosphor plate 125 is removed (i.e., taken along
line 7-7 of FIG. 5C). As shown in FIG. 7 is frame 120, sample
support sheet 122, an air gap/void 138 (since phosphor plate 125 is
removed), and optical platen 126.
[0062] Referring now to FIG. 8, in operation, an object (such as a
small animal) is immobilized on sample object stage 104 (step 200).
An operator configures system 100 for imaging in a first mode, and
an image of the object is captured using lens/camera system 18 in
the first mode (step 202). System 18 converts the light image into
an electronic image which can be digitized. This digitized image is
referred to as Image1 or I1. The digitized image can be displayed
on the display device, stored in memory, transmitted to a remote
location, processed to enhance the image, and/or used to print a
permanent copy of the image. The object remains immobilized on
sample object stage 104; no change in the position/location of the
object is made. The operator configures system 100 for imaging in a
second mode (step 204), and an image of the object is captured
using lens/camera system 18 in the second mode. The resulting
digitized image is referred to as Image2 or 12. Since the position
of the object was not moved/changed during the capture of the
images, both Image1 and Image2 can readily be merged or
superimposed (step 206), using methods known to those skilled in
the art, such that the two images are co-registered. As such, a
third image can be generated comprising Image1 and Image2. Once
imaging is complete, the object/subject is removed from the sample
stage (step 208).
[0063] As indicated above, system 100 can be configured in several
modes, including: x-ray imaging, bright-field imaging, dark-field
imaging (including luminescence imaging, fluorescence imaging) and
radioactive isotope imaging. To configure system 100 for x-ray
imaging or isotope imaging, phosphor plate 125 is moved to position
P1 in optical registration with sample object stage 104 (as shown
in FIGS. 5B and 6). For an x-ray image, x-ray source 102 is
employed when capturing the image of the immobilized object. To
configure system 100 for bright-field imaging or dark-field imaging
(including luminescence imaging and fluorescence imaging) without
moving the immobilized object and the support member or object
stage, phosphor plate 125 is moved to position P2, out of optical
registration with sample object stage 104 (as shown in FIGS. 5C and
7), and an image of the immobilized object is appropriately
captured. The object is immobilized on sample object stage 104, and
light emitted from the object (usually diffusive within the turbid
constituents of a solid object) is projected to the object surface,
which intimately bears upon the upper surface of sample support
sheet 122.
[0064] For the purpose of optical imaging, the object surface is
defined by a refractive boundary (e.g., the skin of an animal) that
delineates the interior of the object (usually a heterogeneous,
turbid media of higher index of refraction) and air. Light
emanating from within an object (e.g., luminescent or transmitted)
projects to the surface from which it scatters, defining the light
that may be productively managed to create an image of the object.
Conversely, light may be provided from beneath optical platen 126
and scattered from the object surface, thereby providing reflective
light for imaging the same object.
[0065] For optical imaging, the definition of the object boundary
may be moderated by matching the refractive index of the object
boundary to support sheet 122 by introducing an index-matching
fluid (e.g., water). The depth to which good focus can be achieved
in optical imaging is dependent on minimizing the surface scatter
of the object, and methods such as index matching and increasing
wavelength (e.g., near-infrared, NIR imaging) are well known in the
art.
[0066] The emitted sample light can arise from luminescence,
fluorescence or reflection, and the focal plane of the lens can be
adjusted to the elevation of object surface. Alternatively, the
"light" can be ionizing radiation passing through or emitted from
the object, or passing into the phosphor and forming an image. Soft
x-rays, consistent with thin objects or small animals, project an
image through the diffusive phosphor onto the optical boundary,
adding the depth of the (more than about 0.02 mm) to the depth of
focus. More significant is the focal distance contributed by the
phosphor support plate 134, which may be fractional millimeters,
depending upon the thickness and index of the glass or plastic. The
fractional-millimeter elevation of the best focal plane contributed
by the phosphor support can provide a better coincidence between
the phosphor focal plane and the focal plane used for optical
imaging. For near infrared (NIR) optical imaging, the
preferred/best focal plane may be located at millimeter depths into
a nominally turbid object. The phosphor support plate 134 can be
thicker to maximize the coincidence of the optical and phosphor
imaging planes. Those skilled in the art will recognize how to tune
the materials of the present invention to optimally co-locate the
preferred optical and phosphor imaging planes. Currently described
materials may be practically assembled to assure multi-modal focal
plane co-location to accommodate the demands of a fast lens
system.
[0067] Appropriately fast lens systems for dark-field and x-ray
imaging applications will likely have sub-millimeter focal depths,
necessitating the above considerations. Accordingly, for a
particular embodiment, it may be desirable for multiple optical
elements to enable the location of a common focal plane shared by
differing modes of imaging.
[0068] Emitted gamma rays from a thick object (such as 99Tc
emission from an animal organ) are distributed over the plane of
the phosphor, diffusing the image by millimeters, and an
appropriately thick phosphor layer (about 0.1 mm) may be preferred
for increased detection efficiency. Consequently, the location of
the focal plane at the supporting sheet is not critical to the
resolution of the radio isotopic image. Better resolution and more
precise planar projection of the emitting isotope can be achieved
by gamma-ray collimation. Collimators of millimeter-resolution are
available and capable of projecting isotopic location to millimeter
resolution at the focal plane of the phosphor in the present
invention.
[0069] Of particular relevance to the operation of the present
invention is the thickness of the layers in the focal plane of the
lens. For example, fast lenses, (which are essential elements for
the practice of imaging low-light emissions) will have a focal
depth of focus of about 0.5 mm for very fast lenses. For good
resolution of objects of interest, less than about 0.2 mm of
spatial resolution is desirable, and a megapixel CCD camera
(cooled) imaging at 100 mm field is suitable. Generally, more
resolution is desirable.
[0070] Precision registration of the multi-modal image can be
accomplished using methods known to those skilled in the art. By
placing the object on a thin, stretched optical support that allows
phosphor plate 125 to be removed without displacement of the
object, co-registered optical imaging is enabled by the same
lens/camera system using epi-illumination methodologies at a
sufficiently similar focal plane.
[0071] Examples are now provided.
[0072] FIGS. 9A-9C show images captured using the apparatus and
method of the present invention. A mouse was immobilized on sample
object stage 104 (step 200 of FIG. 8) of system 100. System 100 was
first configured for NIR fluorescence imaging wherein phosphor
plate 125 is removed from co-registration with frame 100. A first
image was captured and is displayed in FIG. 9A (step 202 of FIG.
8). Next, system 100 was configured for x-ray imaging wherein
phosphor plate 125 is placed in co-registration with frame 100. A
second image was captured and is displayed in FIG. 9B (step 204 of
FIG. 8). Using methods known to those skilled in the art, the first
and second images were merged (step 206 of FIG. 8) and the merged
image is displayed in FIG. 9C. Note that the fluorescent signals
superimposed on the anatomical reference clarify the assignment of
signal to the bladder and an expected tumor in the neck area of
this illustrated experimental mouse.
[0073] It is noted that the first and/or second image can be
enhanced using known image processing methods/means prior to be
merged together. Alternatively, the merged image can be enhanced
using known image processing methods/means. Often, false color is
used to distinguish fluorescent signal from gray-scale x-rays in a
merged image.
[0074] FIGS. 10A-10C provide a further example using the apparatus
and method of the present invention. FIG. 10A is a NIR fluorescence
image of a mouse while FIG. 10B is an x-ray image of the same
immobilized mouse. Using methods known to those skilled in the art,
the first and second images were merged and the merged image is
displayed in FIG. 10C. Prior to being merged, the first and second
images were contrasted. This processing allows particular areas of
the mouse to be visually enhanced for diagnostic purposes. For
example, areas 150,152, and 156 are potential secondary early
detection sites, and area 154 shows the primary tumor injection
site at the knee.
[0075] FIGS. 11A-11C provide yet a further example using the
apparatus and method of the present invention. FIG. 11A is a near
IR fluorescence image of a mouse wrist while FIG. 11B is an x-ray
image of the same immobilized mouse wrist. Using methods known to
those skilled in the art, the first and second images were merged
and the merged image is displayed in FIG. 11C. The merged image
provides a diagnostic image for viewing a potential secondary tumor
site. Note that this image set clearly demonstrates the precision
to which the current invention enables the co-location of objects
from differing imaging modes. The maximum fluorescent signal
emanating from a pre-metastatic tumor on the radius (arm-bone) tip
at the wrist is within about 0.1 mm of the suspect lesion
subsequently identified by microscopic histology.
[0076] A phosphor plate suitable for use with the apparatus and
method of the present invention is disclosed in U.S. Pat. No.
6,444,988 (Vizard), commonly assigned and incorporated herein by
reference. A phosphor plate as described in Vizard is shown in FIG.
12. A suitable phosphor plate 125A for use with the apparatus and
method of the present invention includes a transparent support 210
(such as glass) upon which is coated an interference filter 220
which is a multicoated short-pass filter designed to transmit light
at a specified wavelength (and below) and reflect light above that
wavelength. Plate 125A also includes a thin phosphor layer 240 and
a removable thick phosphor layer 260. Thin phosphor layer 240 is
used for high resolution imaging applications of ionizing radiation
or for very low energy (self-attenuating) ionizing radiation such
as low-energy electrons or beta particles. Thick phosphor layer 260
is used for high energy ionizing radiation that freely penetrates
the phosphor. Thick phosphor layer 260 is removable and is shown in
FIG. 12 overlaying thin phosphor layer 240. Layer 260 is removable
to the position shown in dashed lines out of contact with layer
240.
[0077] The phosphor preferably used in phosphor layers 240 and 260
is Gadolinium Oxysulfide Terbium whose strong monochromatic line
output (544-548 nanometers (NM) is ideal for co-application with
interference optics. This phosphor has technical superiority
regarding linear dynamic range of output, sufficiently "live" or
prompt emission and time reciprocity, and intrascenic dynamic range
which exceed other phosphors and capture media. This phosphor layer
preferably has a nominal thickness of 10-30 micrometers (.mu.m) at
5-20 grams/square foot (g/ft2) of phosphor coverage, optimally
absorbing 10-30 Kev x-rays. Thick phosphor layer 260 has a nominal
thickness of 100 .mu.m at 80 g/ft2 of phosphor coverage.
[0078] The duplex phosphor layers impart flexibility of usage for
which the thick phosphor layer 260 may be removed to enhance the
spatial resolution of the image. Thin phosphor layer 240 intimately
contacts filter 220, whereas thick phosphor layer 260 may be
alternatively placed on thin phosphor layer 240.
[0079] Interference filter 220 transmits light at 551 NM and below
and reflects light above that wavelength. Filter 220 comprises
layers of Zinc Sulfide-Cryolite that exhibits a large reduction in
cutoff wavelength with increasing angle of incidence. The filter
has a high transmission at 540-551 NM to assure good transmission
of 540-548 NM transmission of the GOS phosphor. The filter also has
a sharp short-pass cut-off at about 553 NM, that blue shifts at
about 0.6 NM per angular degree of incidence to optimize optical
gain.
[0080] Glass support 210 should be reasonably flat, clear, and free
of severe defects. The thickness of support 210 can be 2
millimeters. The opposite side 280 of glass support 210 is coated
with an anti-reflective layer (such as Magnesium Fluoride, green
optimized) to increase transmittance and reduce optical artifacts
to ensure that the large dynamic range of the phosphor emittance is
captured.
[0081] FIG. 13 shows steps of a method of producing phosphor layer
240. In step 300, a mixture of GOS:Tb in a binder is coated on a
polytetrafluoroethylene (PTFE) support. The PTFE support enables
release of the coated phosphor layer from the PTFE support and
subsequent use of the phosphor layer without support, since
conventional supporting materials are an optical burden to phosphor
performance. For the thin phosphor layer 240, at step 320 an ultra
thin (about 0.5 g/ft2, 0.5 .mu.m thick) layer of cellulose acetate
overcoat can be applied to offer improved handling characteristics
of the thin phosphor layer and to provide greater environmental
protection to the underlying optical filter. At step 340, the
phosphor layer is removed from the PFTE support. At step 360, the
thin phosphor layer overcoated side is overlayed on interference
filter 220. Clean assembly of the thin phosphor layer 240 and
filter 220 assures an optical boundary that optimizes management of
phosphor light output into the camera of the lens/camera system.
Optical coupling of layer 240 and filter 220 is not necessary,
since performance reduction may result. At step 380, layer 240 can
be sealed around its periphery and around the periphery of filter
220 for mechanical stability and further protection of the critical
optical boundary against environmental (e.g., moisture)
intrusion.
[0082] FIG. 14 illustrates schematically how an image captured
using the configuration of FIG. 5C can be merged or co-registered
with an image captured using the configuration of FIG. 5B. A first,
optical image 400 is acquired of the underside of the object
immobilized on sample object stage 104. A second, x-ray image 402
is acquired of the object using x-rays coming from above, as
illustrated. Then an image 404 is prepared that co-registers or
merges images 400, 402.
[0083] FIG. 15A illustrates schematically a system for capturing
visible light images from both sides of an immobilized object while
phosphor plate 125 is in position P2. In addition to a first mirror
16 located beneath sample object stage 104 as illustrated to
reflect light from the underside of the object to lens/camera
system 18 to capture a first optical image, a second mirror 406 is
located on the opposite side or above sample object stage 104 as
illustrated to reflect light from the upper side of the object to
lens/camera system 18 to capture a second optical image.
Preferably, mirror 406 is transparent to x-rays or can be moved by
means not illustrated to a position not proximate object stage 104
during x-ray imaging.
[0084] FIG. 15B illustrates schematically how the system of FIG.
15A may be used for capturing an x-ray image from one side of an
immobilized object while phosphor plate 125 is in position P1.
Mirror 406 may be transparent to x-rays or may have been moved
aside as previously described. Thus, x-rays pass through the object
from above and strike phosphor plate 125, thus causing production
of phosphorescence which is reflected by mirror 16 to camera/lens
system 18 to capture a first x-ray image. Those skilled in the art
will understand that a digital x-ray image captured in this manner
using x-rays from above can be processed by control system 20 to
produce a second, virtual x-ray image of the object as if x-rays
have passed through the object from below. Available software
applications for producing such a virtual image include Kodak MI
marketed by Carestream Health, Inc.; and ImageJ available from the
National Institutes of Health.
[0085] FIG. 15C illustrates how optical images captured as in FIG.
15A may be merged or co-registered with x-ray images captured as in
FIG. 15B. An optical image 408 is prepared showing images of both
the underside and the upper side of the object on sample object
stage 104. An x-ray image 410 is acquired of the object using
x-rays from above as illustrated. An x-ray image 412 is prepared
showing both image 410 and a virtual image of the object as if
x-rays have passed from below. Then an image 414 is prepared that
co-registers or merges images of the respective portions of images
408, 412.
[0086] Advantages of the present invention include: provides
anatomical localization of molecular imaging agent signals in small
animals, organs, and tissues; provides precise co-registration of
anatomical x-ray images with optical molecular and radio isotopic
images using one system; promotes improved understanding of imaging
agent's biodistribution through combined use of time lapse
molecular imaging with x-ray imaging; and allows simple switching
between multi-wavelength fluorescence, luminescence,
radio-isotopic, and x-ray imaging modalities without moving the
object/sample.
[0087] The invention has been described in detail with particular
reference to a presently preferred embodiment, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention. The presently disclosed
embodiments are therefore considered in all respects to be
illustrative and not restrictive. The scope of the invention is
indicated by the appended claims, and all changes that come within
the meaning and range of equivalents thereof are intended to be
embraced therein.
PARTS LIST
[0088] 10 electronic imaging system [0089] 12 light source [0090]
14 optical compartment [0091] 16 mirror [0092] 18 lens/camera
system [0093] 20 communication/computer control system [0094] 22
monitor [0095] 100 imaging system of the present invention [0096]
102 x-ray source [0097] 104 sample object stage [0098] 106
epi-illumination; fiber optics [0099] 108 sample environment [0100]
110 access means/member [0101] 120 frame [0102] 122 support sheet
[0103] 125, 125A phosphor plate [0104] 126 optical platen [0105]
128 protective layer [0106] 130 phosphor layer [0107] 132 optical
layer [0108] 134 support plate; glass [0109] 136 air gap/void
[0110] 138 air gap/void [0111] 150, 152, 154, 156
example--potential secondary early detection sites/area. [0112]
200-208 method steps [0113] 210 transparent glass support [0114]
220 interference filter coating [0115] 240 thin phosphor layer
[0116] 260 thick phosphor layer [0117] 280 opposite side of 210
[0118] 300-380 method steps [0119] 400 optical image of underside
of object [0120] 402 x-ray image through object from above [0121]
404 co-registered or merged images 400, 402 [0122] 406 mirror,
reflects light, transparent to x-rays [0123] 408 optical images of
underside and upper side of object [0124] 410 x-ray image through
object from above [0125] 412 image 410 and virtual x-ray image
through object from below [0126] 414 co-registered or merged images
408, 412 [0127] A path of movement of 125 [0128] P1 position of 125
proximate 104 [0129] P2 position of 125 not proximate 104
* * * * *