U.S. patent application number 13/236011 was filed with the patent office on 2012-01-12 for irradiation system including an electron-beam scanner.
This patent application is currently assigned to L-3 Communications Security and Detection Systems, Inc.. Invention is credited to Douglas P. Boyd, Boris Oreper, Nikolay Rolshud.
Application Number | 20120008746 13/236011 |
Document ID | / |
Family ID | 41530288 |
Filed Date | 2012-01-12 |
United States Patent
Application |
20120008746 |
Kind Code |
A1 |
Oreper; Boris ; et
al. |
January 12, 2012 |
IRRADIATION SYSTEM INCLUDING AN ELECTRON-BEAM SCANNER
Abstract
A property of a treatment beam is controlled during a scanning
period. A portion of a region is exposed to an imaging x-ray beam
during a scanning period, the imaging x-ray beam being generated by
an electron-beam scanner. X-ray radiation from the region is
detected, the x-ray radiation representing an attenuation of the
imaging x-ray beam caused by the portion of the region. A first
image of the portion of the region is generated based on the
detected x-ray radiation. A characteristic of the portion of the
region is determined from the generated first image. An input
derived from the characteristic is generated, the input configured
to cause a source of a treatment beam to modify a property of the
treatment beam. The source of the treatment beam modifies a
property of the treatment beam during the scanning period by
providing the input to the source of the treatment beam.
Inventors: |
Oreper; Boris; (Chestnut
Hill, MA) ; Boyd; Douglas P.; (Las Vegas, NV)
; Rolshud; Nikolay; (Winchester, MA) |
Assignee: |
L-3 Communications Security and
Detection Systems, Inc.
Wobum
MA
|
Family ID: |
41530288 |
Appl. No.: |
13/236011 |
Filed: |
September 19, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12871981 |
Aug 31, 2010 |
8059783 |
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13236011 |
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12503560 |
Jul 15, 2009 |
7899156 |
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12871981 |
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61094549 |
Sep 5, 2008 |
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61081360 |
Jul 16, 2008 |
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Current U.S.
Class: |
378/65 |
Current CPC
Class: |
A61B 6/032 20130101;
A61B 6/508 20130101; A61B 6/4007 20130101; A61N 5/1067 20130101;
A61N 2005/1061 20130101; A61B 6/4028 20130101; A61N 5/1049
20130101; A61B 6/466 20130101 |
Class at
Publication: |
378/65 |
International
Class: |
A61N 5/10 20060101
A61N005/10 |
Claims
1. A method of controlling a treatment beam during a scanning
period, the method comprising: exposing a portion of a region to an
imaging x-ray beam during a scanning period, the imaging x-ray beam
being generated by an electron-beam scanner; detecting x-ray
radiation from the region, the x-ray radiation representing an
attenuation of the imaging x-ray beam caused by the portion of the
region; generating a first image of the portion of the region based
on the detected x-ray radiation; determining a characteristic of
the portion of the region from the generated first image;
generating an input derived from the characteristic, the input
configured to cause a source of a treatment beam to modify a
property of the treatment beam; and causing the source of the
treatment beam to modify a property of the treatment beam during
the scanning period by providing the input to the source of the
treatment beam.
2. The method of claim 1, wherein the characteristic of the portion
comprises the position of the portion, and causing the source of
the treatment beam to modify a property of the treatment beam
comprises modifying a direction of propagation of the treatment
beam such that the treatment beam irradiates the portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/871,981, filed Aug. 31, 2010, titled
IRRADIATION SYSTEM INCLUDING AN ELECTRON-BEAM SCANNER, which is a
divisional of U.S. patent application Ser. No. 12/503,560 titled
IRRADIATION SYSTEM INCLUDING AN ELECTRON-BEAM SCANNER and filed
Jul. 15, 2009, now U.S. Pat. No. 7,899,156, which claims the
benefit of U.S. Provisional Application Ser. No. 61/094,549 titled
IRRADIATION SYSTEM INCLUDING AN ELECTRON-BEAM SCANNER and filed
Sep. 5, 2008, and U.S. Provisional Application Ser. No. 61/081,360,
titled IRRADIATION WITH E-BEAM SCANNER and filed Jul. 16, 2008. The
prior applications are incorporated by reference herein in their
entirety.
TECHNICAL FIELD
[0002] This disclosure relates to an irradiation system that
includes an electron-beam scanner.
BACKGROUND
[0003] Computer tomography (CT) systems can be used to image a
patient, including, for example, a patient's tumor. An irradiation
system can deliver high-energy radiation, such as x-ray radiation,
to the tumor to destroy the tumor.
SUMMARY
[0004] In one general aspect, a system includes an electron-beam
scanner, a source of irradiation energy, and a processor. The
electron-beam scanner includes an electron emitter configured to
produce an electron beam, an electron accelerator configured to
accelerate the electron beam toward a target that produces an x-ray
beam in response to being struck by the electron beam, a steering
device configured to scan the electron beam along the target such
that the produced x-ray beam is positioned relative to a portion of
a region to be imaged, and a detector configured to sense x-ray
radiation from the region and produce a representation of the
sensed radiation. The source of irradiation energy is configured to
produce a treatment beam. The electron beam scanner and the source
of irradiation energy are positioned to allow the portion of the
region to be exposed to the treatment beam and the produced x-ray
beam concurrently. The system also includes a processor operable to
receive the representation of the sensed x-ray radiation, determine
a characteristic of the imaged portion of the region based on the
representation of the sensed x-ray radiation, and modify a property
of the treatment beam based on the characteristic. Implementations
may include one or more of the following features. The electron
beam scanner may be positioned at an angle relative to a direction
of propagation of the treatment beam. The system also may include a
gantry, and the electron beam scanner and the source of irradiation
energy may both be located within the gantry. The electron-beam
scanner may be movable with respect to the gantry and the processor
may be further operable to determine a position of the
electron-beam scanner relative to the gantry and a position of the
produced x-ray beam relative to the gantry.
[0005] In some implementations, the characteristic of the portion
of the region may include one or more of a position of the portion,
a size of the portion, and a shape of the portion. The processor
may be further operable to generate an image of the region based on
the representation of the sensed radiation. The portion may include
a biological structure within a human patient. The region may
include a pancreas, and the portion of the region may include a
portion of the pancreas.
[0006] To control the treatment beam based on the characteristic,
the processor may be further operable to provide an input to the
source of irradiation energy, the input being derived from the
characteristic of the portion of the region and the input being
sufficient to cause the source of irradiation energy to modify a
property of the treatment beam. The processor may provide the input
to the source of irradiation energy while the produced x-ray beam
illuminates the portion of the region. The processor may provide
the input to the source of irradiation energy while the portion of
the region is imaged by the x-ray beam. The processor may provide
input to the source of irradiation energy during a treatment
session. The property of the treatment beam may include one or more
of a beam profile of the treatment beam and an intensity of the
treatment beam. The characteristic of the object may include a size
and shape of the object, and the input to the source of irradiation
energy may be sufficient to cause the source of irradiation energy
to modify a beam profile of the treatment beam such that the
profile approximately matches a size and shape of the object.
[0007] In another general aspect, during a scanning period in which
a portion of a region is imaged by an electron-beam scanner, first
data produced by the electron-beam scanner is received. The first
data includes a first indication of a characteristic of the
portion. During the scanning period, a characteristic of the
portion from the first data is determined. During the scanning
period, a first input derived from the characteristic is provided
to a source of a treatment beam, the first input being sufficient
to cause the source of the treatment beam to modify a property of
the treatment beam. During the scanning period, second data
produced by the electron-beam scanner is received. The second data
is received after the first data and the second data includes a
second indication of the characteristic of the portion. During the
scanning period, the characteristic of the portion from the second
data is determined. During the scanning period, a second input
derived from the characteristic determined from the second data is
provided to the source of an irradiation beam, the second input
being sufficient to cause the source of the treatment beam to
modify the property of the treatment beam to account for the
characteristic determined from the second data.
[0008] Implementations may include one or more of the following
features. The property of the treatment beam may include a beam
profile of the treatment beam. The characteristic of the portion
may include a shape of the portion, and the shape of the portion
may vary during the scanning period. The portion may move during
the scanning period. The region may include a human patient and the
portion of the region may include a biological structure within the
human patient. The property of the treatment beam may be a beam
profile of the treatment beam and the first input and the second
input are inputs sufficient to cause a leaf of a multi-leaf
collimator coupled to the source of the treatment beam to move such
that the beam profile is modified. The characteristic of the
portion of the region may be a position, and the first input and
the second input are inputs sufficient to cause the source of the
treatment beam to direct the treatment beam toward the position of
the portion. The portion of the region may include a biological
structure of a patient, and the scanning period may be a continuous
treatment session during which the patient remains in the region
and the treatment beam irradiates the biological structure.
[0009] In some implementations, the second input may be provided to
the source of the irradiation beam no more than one hundred
milliseconds after the first input is provided to the source of the
irradiation beam.
[0010] In another general aspect, a treatment beam is controlled
during a scanning period. A portion of a region is exposed to an
imaging x-ray beam during a scanning period, the imaging x-ray beam
being generated by an electron-beam scanner. X-ray radiation from
the region is detected, the x-ray radiation representing an
attenuation of the imaging x-ray beam caused by the portion of the
region. A first image of the portion of the region is generated
based on the detected x-ray radiation. A characteristic of the
portion of the region is determined from the generated first image.
An input derived from the characteristic is generated, the input
configured to cause a source of a treatment beam to modify a
property of the treatment beam. The source of the treatment beam
modifies a property of the treatment beam during the scanning
period by providing the input to the source of the treatment
beam.
[0011] Implementations may include one or more of the following
features. The characteristic of the portion may include the
position of the portion, and causing the source of the treatment
beam to modify a property of the treatment beam may include
modifying a direction of propagation of the treatment beam such
that the treatment beam irradiates the portion.
[0012] In another general aspect, an apparatus to control a
treatment beam based on data from an electron-beam scanner is
assembled. A source of an irradiation energy configured to produce
a treatment beam is positioned in a housing, and an electron-beam
scanner configured to produce an x-ray imaging beam is positioned
in the housing relative to the source of irradiation energy. The
positioning of the electron-beam scanner allows an object in a
region within the housing to be exposed to the treatment beam and
the x-ray imaging beam concurrently.
[0013] Implementations of the techniques discussed above may
include a method or process, a system or apparatus, or computer
software on a computer-readable medium.
DESCRIPTION OF THE DRAWINGS
[0014] FIGS. 1A and 1B illustrate perspective views of a circular
configuration electron-beam scanner.
[0015] FIG. 1C illustrates an example of a collimator.
[0016] FIG. 1D illustrates an example of a detector system.
[0017] FIGS. 1E and 1F illustrate example geometries for an
electron-beam scanner.
[0018] FIG. 2 illustrates an example of a linear configuration
electron-beam scanner.
[0019] FIG. 3 illustrates a horizontal cross-section of an
irradiation system that includes an electron-beam scanner.
[0020] FIG. 4A illustrates a side vertical cross-section of a
system that includes an irradiation system and an electron-beam
scanner.
[0021] FIGS. 4B and 4D illustrate front perspective views of the
system shown in FIG. 4A.
[0022] FIG. 4C illustrates a rear perspective view of the system
shown in FIG. 4A.
[0023] FIGS. 5A and 5B illustrate rear perspective views of another
system that includes an irradiation system and an electron-beam
scanner.
[0024] FIG. 5C illustrates a front perspective view of the system
shown in FIGS. 5A and 5B.
[0025] FIG. 5D illustrates a front vertical cross-sectional view of
the system shown in FIGS. 5A and 5B.
[0026] FIG. 5E illustrates a side vertical cross-sectional view of
the system shown in FIGS. 5A and 5B.
[0027] FIG. 5F illustrates a bottom cross-sectional view of the
system shown in FIGS. 5A and 5B.
[0028] FIG. 6 is a block diagram of an example system that includes
an irradiation system and an electron-beam scanner.
[0029] FIG. 7 is an example process for modifying a property of a
treatment beam based on a characteristic of an object imaged by an
electron-beam scanner.
[0030] Like reference numbers refer to like elements.
DETAILED DESCRIPTION
[0031] An electron-beam scanner capable of rapidly imaging a region
of a patient (such as a tumor) can be combined with an irradiation
system that delivers high-energy radiation (which may be referred
to as a treatment beam) to the tumor imaged by the electron-beam
scanner. The electron-beam scanner (e-beam scanner) scans a region
at a rate of ten scans per second or higher and, thus, is able to
generate clear images of the region even if the region (or a
portion of the region) moves. The images generated by the
electron-beam scanner are used to control and shape the treatment
beam such that the treatment beam matches the imaged region or
portion thereof, for example a tumor within or on the imaged region
of the patient. In this manner, the amount of radiation delivered
to the tumor may be increased relative to the amount of radiation
delivered to the surrounding tissue. For convenience, area within
or on a patient (such as, for example, a tumor, an organ, a portion
of an organ, or another type of biological structure) that is to
receive treatment may be referred to as an object.
[0032] Referring to FIGS. 1A and 1B, an example electron-beam
scanner 100 scans a region 105 with an electron beam generated from
a first electron emitter 110 and a second electron emitter 115. The
first and second electron emitters may be electron guns that emit a
beam of electrons. In some implementations, the first and second
electron emitters may be thermionic emitters, electron emitters
made from carbon nanotubes, or photo emitters. The first and second
electron emitters may both be the same type of emitter, or the
first and second electron emitters may each be a different type of
emitter. FIG. 1A shows a rear perspective view of the electron-beam
scanner 100 and FIG. 1B shows a front perspective view of the
electron-scanner 100. The electron-beam scanner 100 is a circular
configuration of an electron-beam scanner. Other implementations
may include different configurations, such as a linear
configuration of the electron beam scanner. For example, FIG. 2
shows a linear configuration of an electron-beam scanner.
[0033] The electron beam from the electron guns 110 and 115 creates
a scan beam (not shown) within the region 105. The scan beam scans
the region 105 at a rate of ten scans per second or higher (for
example, about fifty scans per second) to image objects within the
region 105 (such as a portion of a human patient, a biological
structure, or a tumor within the patient). The object may be
considered to be a portion of the region 105. Because the region
105 is scanned at a rate of at least ten scans per second, tumors
within the patient that move as a result of normal bodily functions
(even when a person is lying still or attempting not to move), such
as a tumor in or around the patient's lungs that moves continuously
as the patient breathes, may be imaged as the tumors move. Scanning
the region 105 at a rate of at least ten scans per second allows
clear, non-blurred images of the moving tumors to be generated.
Thus, the images generated by scanning the region 105 may be used
to determine a profile or shape of a tumor within the patient as
the tumor moves due to normal bodily functions.
[0034] The electron-beam scanner 100 is combined with an
irradiation system (not shown) that delivers a high-energy
radiation treatment beam (such as gamma radiation or x-ray
radiation) to the tumors in order to destroy the tumor. By
combining the electron-beam scanner 100 with the irradiation
system, the images generated from the electron-beam scanner 100 may
be used to control a property of the treatment beam, such as the
direction and/or beam shape of the treatment beam, provided by the
irradiation system. In particular, the determined profile of the
tumor is used to digitally control a beam profile and position of
the treatment beam from the irradiation system. Digitally
controlling the beam profile and position of the treatment beam
allows the treatment beam to be matched to the tumor such that the
tumor receives as much radiation as possible (thus helping to
ensure that the tumor is destroyed) while also preventing or
minimizing the exposure of nearby tissues and structures to the
treatment beam (thus helping to prevent damage to the nearby tissue
and structures). Additionally, because the electron-beam scanning
system 100 scans the region 105 at a rate of at least ten scans per
second, the treatment beam can be quickly adjusted to track and
target the changing shape and/or location of the tumor (for
example, as the tumor moves due to normal bodily functions).
[0035] In the example shown in FIG. 1A, the electron-beam scanner
100 includes two electron guns, the electron gun 110 and the
electron gun 115. Each of the electron guns 110 and 115 include a
high-voltage connector that connects the electron gun 110 and the
electron gun 115 to a power source. In the example shown, the
electron gun 110 includes the high-voltage connector 111, and the
electron gun 115 includes the high-voltage connector 116. The power
source supplies a voltage sufficient to generate a voltage
potential through which electrons in the electron beam are
accelerated by accelerators 112 and 117 to a target (not shown), to
produce x-ray radiation. The accelerators 112 and 117 may be
referred to as electron accelerators. The produced x-ray radiation
passes through a collimator 125, which shapes the x-ray radiation
into a scan beam that can fill the region 105. Referring to FIG.
1C, the collimator 125 may be a rounded shell of a high-density
material, such as lead or tungsten, that blocks x-rays. The
collimator 125 includes an open slot 127 through which the x-rays
generated from the electron beam striking the target pass to form
an x-ray scan beam that fills the region 105. In some
implementations, the scan beam may be a cone beam of x-ray
radiation and the electron-beam scanner 100 may be a cone beam
volumetric tomography system.
[0036] Referring again to FIGS. 1A and 1B, the object to be imaged
may extend beyond the scan region 105. However, the scan region 105
may be applied to the portions of the object that are outside of
the scan region 105 by moving the scan region 105 or by moving the
object to be imaged into or through the scan region 105. Radiation
from the scan beam that passes through the scan region 105 and
through items within the scan region 105 is detected by a detection
system 130 and used to generate an image of the scan region 105.
The images may be three-dimensional computed tomography images.
[0037] Referring to FIG. 1D, an example of the detection system 130
is shown. The detection system 130 includes a material 134 that is
sensitive to the energies in the scan beam. The material 134 may be
a scintillation material that is sensitive to the energies in the
scan beam and converts the energies in the scan beam into light.
The material 134 may be a crystalline material such as cadmium
tungsten (CdW), and the material 134 may have an overall circular
or semi-circular cross-section to match the circular cross section
of the region 105. However, the material 134 is made up of
rectangular sections, or stripes. Multiple stripes make up an arc,
but the individual stripes are rectangular or otherwise linear. The
detector 134 may be mounted on an arc around the region 105. For
example, the material 134 may be formed as a 180-degree half-circle
centered around the region 105. In other examples, the detector 134
may be formed as an arc of more than 180-degrees, such as a
210-degree arc around the region 105. The detection system 130 also
includes detector board electronics 136. The detector board
electronics 136 converts the radiation sensed by the material 134
into an electrical signal from which an image of the region 105 is
made.
[0038] Referring again to FIGS. 1A and 1B, although the example
shown in FIG. 1A includes the two electron guns 110 and 115 and the
two corresponding accelerators 112 and 117, in other examples more
or fewer electron guns may be used. Using more than one electron
gun allows for the size of the system 100 to be reduced as compared
to implementations in which one electron gun is used. For example,
each electron gun may be able to scan over a distance that is
determined by the distance of the electron gun from the object to
be imaged and the maximum electron beam deflection angle. Thus,
implementations that include one electron gun scan the x-ray beam
over a relatively shorter total distance or include electron guns
that are placed further from the object to be imaged in order to be
able to scan the x-ray beam over a longer total distance. However,
by using more than one electron gun, the electron guns may be
placed closer to the object to be imaged because, together, the
electron guns scan the x-ray beam over a longer distance than
possible with a single electron gun scanning at the maximum
deflection angle. Thus, using two electron guns results in the
electron-beam scanner 100 being about half of the size of a system
that uses one electron gun.
[0039] Referring to FIG. 1E, an example geometry of a system that
uses two electron guns (such as the electron-beam scanner 100) is
shown, and, referring to FIG. 1F, an example geometry of a system
that uses one electron gun is shown. In each of the example
geometries, the electron guns produce a beam having a total
deflection angle of 70.2 degrees and the beam is scanned over a
total distance of one meter at a target location "T." However,
using the geometry shown in FIG. 1E results in a smaller system
because the two electron guns are placed 0.34 meters from the
target location "T" as compared to the one electron gun in the
geometry shown in FIG. 1F, which is placed 0.71 meters from the
target location "T." Thus, using the two electron guns 110 and 115
shown in FIG. 1A results in a smaller system to scan the same size
region.
[0040] Referring to FIG. 2, an example of a linear configuration
electron-beam scanner 200 is shown. The electron-beam scanner 200
scans a region 205 with a scan beam (not shown) that is generated
from a first electron gun 210 and a second electron gun 215. The
scan beam scans the region 205 at a rate of ten scans per second or
higher (e.g., fifty scans per second) to image objects within the
region 205 (such as a portion of a patient 225, a biological
structure, or a tumor within the patient 225). The scan beam is a
beam of radiation such as an x-ray beam. For example, the scan beam
may be a cone beam of radiation and the electron-beam scanner 200
may be a cone beam volumetric tomography system.
[0041] Images generated by scanning the region 205 may be used to
determine a profile of the tumor within the patient 225, even as
the tumor moves, and the determined profile is used to digitally
control a beam profile and position of an x-ray treatment beam used
to irradiate and destroy the tumor. Objects outside of the region
205 may be imaged by the scan beam by moving the objects into the
region 205 and/or by moving the region 205.
[0042] In the example shown in FIG. 2, a portion of the patient 225
is within the region 205, and the scan beam is used to image the
portion of the patient 225 along with biological structures and/or
other objects within the portion of the patient 225. Radiation from
the scan beam that passes through the patient 225 is detected by a
detection system 230 and used to generate an image of the region
205. The images may be three-dimensional computed tomography
images. The detector system 230 includes a detector array that is
sensitive to the energies included in the scan beam and electronics
that convert the sensed energies into electrical signals that are
used to generate an image of the region 205.
[0043] Because the region 205 is scanned at a rate of at least ten
scans per second, structures within the patient 225 that move as a
result of normal bodily functions, such a tumor in or around the
patient's 225 lungs that moves continuously as the patient 225
breathes, may be imaged as the structures move. Scanning the region
205 at a rate of at least ten scans per second allows clear,
non-blurred images of the moving structures to be generated.
[0044] The electron-beam scanner 200 includes two electron guns,
the electron gun 210 and the electron gun 215. Each of the electron
guns 210 and 215 respectively include the high-voltage connectors
211 and 216, which connect the electron gun 210 and the electron
gun 215 to a power source. The power source supplies a voltage
sufficient to generate a voltage potential through which electrons
in the electron beam are be accelerated by accelerators 212 and 217
to a target (not shown), to produce x-ray radiation.
[0045] Although the example shown in FIG. 2 includes the two
electron guns 210 and 215 and the two corresponding accelerators
212 and 217, in other examples more or fewer electron guns may be
used. As discussed above with respect to FIGS. 1E and 1F, using
more than one electron gun allows for the size of the system 200 to
be reduced as compared to implementations in which one electron gun
is used.
[0046] Referring to FIG. 3, a horizontal cross-section of an
irradiation system 300 that includes an electron-beam scanner 305
is shown. The irradiation system 300 also includes a gantry 310 and
a patient table 320. In the example shown, the electron-beam
scanner 305 is similar to the linear configuration electron-beam
scanner 200 discussed with respect to FIG. 2. However, in other
implementations, the electron-beam scanner 305 may be a circular
configuration electron-beam scanner such as the electron-beam
scanner 100 discussed with respect to FIGS. 1A and 1B. The
electron-beam scanner 305 is placed in the gantry 310. The
electron-beam scanner 305 is used to image a portion of the patient
to, for example, image a tumor within the patient. The irradiation
system 300 produces a treatment beam that is shaped and directed
toward the tumor within the patient to destroy the tumor by
irradiating the tumor with the treatment beam. Placing the
electron-beam scanner 305 in the gantry 310 allows the treatment
beam be moved with respect to the patient table 320 such that the
treatment beam can be directed to the portion of the patient that
includes the tumor to be destroyed. Additionally, placing the
electron-beam scanner 305 in the gantry allows the scan beam to be
moved and the position of the scan beam tracked with respect to the
known position of the gantry 310.
[0047] Referring to FIGS. 4A and 4B, a side vertical
cross-sectional view of an example system 400 and a front
perspective view of the system 400 are respectively shown. The
system 400 includes an irradiation system 405 that produces a
high-energy treatment beam 460 and an electron-beam scanner system
that is used to image a patient 457. In the example shown in FIGS.
4A and 4B, the electron-beam scanner system is a linear
configuration electron-beam scanner system similar to the
electron-beam scanner system discussed above with respect to FIG.
2. The system 400 includes a gantry 410, which houses an
electron-beam scan chamber 420 that produces a scan beam 440 within
an x-ray beam region 445. In some implementations, the
electron-beam scan chamber 420 may be removed from the gantry 410,
perhaps by a robotic arm. In other implementations, the
electron-beam scan chamber 420 may be permanently, or
semi-permanently, affixed to the gantry 410 by, for example,
bolting the electron-beam scan chamber 420 to the gantry 410.
[0048] In the example shown in FIG. 4A, images of the patient 457,
and biological structures within or on the patient 457, are
generated using the electron-beam scanner system. The images of the
patient 457 may be volumetric computed tomography images. A
high-energy x-ray beam 460, which may be referred to as a treatment
beam 460, is produced by the irradiation system 405 and irradiates
a target structure, such as a cancerous tumor, within the patient
457. The target structure is identified from images of the patient
457 generated by the electron-beam scanner system.
[0049] The treatment beam 460 delivers x-ray radiation to the
tumor, or other target structure, while minimizing or eliminating
the exposure of nearby tissue and structures to the radiation in
the treatment beam 460. To minimize or eliminate the exposure of
nearby tissue to the radiation in the treatment beam 460, the
treatment beam 460 is shaped by a digitally controlled multi-leaf
collimator and delivered to the site of the target structure as
identified by the images of the tumor in the patient 457 that are
generated by the electron-beam scanner system. The multi-leaf
collimator may be made up of multiple segments of a material, such
as lead or tungsten, that blocks energies included in the treatment
beam 460. The segments of the collimator move independently, and by
controlling the placement of the segments, selective portions of
the treatment beam 460 may be blocked, thus controlling the shape
of the beam profile of the treatment beam 460. For example, the
multi-leaf collimator may include sixty-four individually
controllable and moveable segments that may be moved in and out of
the path of the treatment beam 460 in order to selectively block
and transmit portions of the treatment beam 460. In other examples,
the multi-leaf collimator may include more or fewer individually
controllable and moveable segments.
[0050] Images of a target structure within the patient 457 are
generated by the electron-beam scanner system and analyzed to
determine the shape (or profile) of the target structure and the
location of the target structure within the patient 457. In
particular, images of the target structure are generated and
analyzed at a rate of at least ten images per second. This allows
the profile of the target structure and the location of the target
structure to be tracked even if the target structure moves while
the region 445 is scanned.
[0051] Additionally, the electron-beam scanner 420 may be angled at
an angle 465 with respect to the treatment x-ray 460 such that
detectors (such as the detectors 230) do not block the treatment
beam 460 and prevent the treatment beam 460 from reaching the
patient 457. The angle 465 may be defined with respect to a
direction of propagation of the treatment beam 460. The scan beam
440 may be angled with respect to the treatment beam 460 by
installing the electron-scanner system in the gantry 410 at the
angle 465. The angle 465 may be, for example, thirty-five degrees
or less, or the angle 465 may be between three and seventy-five
degrees. Positioning the scan beam 440 at the angle 465 prevents
the detectors from blocking the treatment beam 460. Alternatively,
or additionally, the detectors may be displaced or offset laterally
along the gantry 410 with respect to the treatment beam 460 such
that the detectors do not block the treatment beam 460 but the
detectors are still positioned close enough to the scan beam 440 to
ensure that the detectors sense sufficient signal to form an image
of the region 445. For example, the detectors may be displaced 100
millimeters closer to a head of the patient 457 or closer to the
feet of the patient 457 with respect to the treatment beam 460.
[0052] Referring to FIG. 4C, a rear perspective view of the system
400 is shown. In the example shown in FIG. 4C, the electron-beam
scan chamber 420, detectors, and the treatment beam 460 are moved
with respect to the patient 357 within the gantry 410 to image and
irradiate different portions of the patient 457. Because the
electron-beam scanner 420 and the treatment beam 460 are moved
together within the gantry 410 with respect to the patient 457, the
images of the region 445 remain registered with respect to the
gantry 410 such that the location of the structure to be irradiated
with the treatment beam 460 is known and can be targeted by the
treatment beam 460. Referring to FIG. 4D, a front view of the
system 400 is shown. In the example of FIG. 4D, the electron beam
scan chamber 420, the x-ray beam region 445, and the treatment beam
460 have moved counter clockwise by about forty-five degrees as
compared to the example shown in FIG. 4B.
[0053] Referring to FIG. 5A, a vertical perspective rear view of an
example system 500 that combines a circular configuration
electron-beam scanner system and an irradiation system is shown.
The electron-beam scanner system in the system 500 has a circular
configuration that may be similar to the electron-beam scanner
system 100 discussed above with respect to FIGS. 1A and 1B. The
scan beam produced by the electron-beam scanner system included in
the system 500 scans an object within a scan region 525. In the
example shown, the electron-beam scanner system has a circular
configuration and the region 525 has a circular, or semi-circular,
cross-section.
[0054] The system 500 is placed within a gantry 510, and electron
guns 515 and 520 generate an electron beam that is used to generate
a scan beam that scans a portion of a patient 522 that is within
the scan region 525 while the patient 522 rests on a table 523.
Radiation from the scan beam that passes through the patient 522 is
detected by a detector 530 (which may be a circular detector
similar to the detector 130 discussed with respect to FIGS. 1A and
1D) to form an image of the portion of the patient 522 that is
within the scan region 525 and biological structures within and/or
on the patient 522. Thus, the electron-beam scanner system is used
to generate images of the portion of the patient 522 that is within
the region 525. Profiles of a target structure within or on the
patient 522 (such as a tumor) are determined from the images, and
the profiles are used to control a therapy beam 535, which is
generated by the irradiation system. The therapy beam 535 may be
referred to as a treatment beam 535. In particular, the profiles
may be used to control the beam profile of the therapy beam 535 and
direction of the therapy beam 535 such that the irradiation of the
target structure is maximized while radiation to the tissue and
biological structures in the vicinity of the target structure is
minimized. In the example shown, the treatment beam 535 is offset
from the detector 530 such that the detector 530 does not prevent
the treatment beam 535 from reaching the patient 522.
[0055] FIGS. 5B-5F show various views of the system 500. In
particular, FIG. 5B shows a rear perspective view of the
irradiation system 500, FIG. 5C shows a front perspective view of
the irradiation system 500, FIG. 5D shows a front vertical
cross-sectional view of the irradiation system 500, FIG. 5E shows a
side vertical cross-sectional view of the irradiation system 500,
and FIG. 5F shows a bottom cross-sectional view of the irradiation
system 500.
[0056] FIG. 6 is a block diagram of an example system that includes
an irradiation system 620 and an electron-beam scanner 610. The
irradiation system 600 includes an irradiation source 620 that
produces a treatment beam 622. The system 600 includes an e-beam
scanner 610, a source of irradiation energy 620, an input/output
interface (I/O interface) 630, a processor 640, and an electronic
storage 650. The e-beam scanner may be any of the e-beam scanners
discussed above. In some implementations, the e-beam scanner 610
may be an e-beam scanner similar to those discussed in U.S. Pat.
No. 7,428,297, which is hereby incorporated by reference in its
entirety.
[0057] The e-beam scanner 610 produces an x-ray beam that is used
to image a region that is also irradiated by the treatment beam
produced by the source of irradiation energy 620. The e-beam
scanner includes an electron emitter 612 that emits a beam of
electrons, an electron accelerator 614 that accelerates the
electrons in the beam of electrons, and a target material 615 that
produces x-rays in response to being struck by the accelerated
electrons.
[0058] The e-beam scanner 610 also includes a steering device 616,
which moves the beam of electrons across the target material 615.
Moving the beam of electrons across the target material 615 may
also be considered scanning the beam of electrons across the target
material 615 or positioning the beam of electrons at a particular
place along the target material 615. Moving the beam of electrons
across the target material 615 results in the x-ray beam produced
by the interaction with the target material 615 having a
corresponding motion relative to the portion of the region. As a
result, the produced x-ray beam moves across the region to image
the region or the portion of the region. The steering device 616
may include a magnet that is positionable to direct the beam of
electrons in a particular direction.
[0059] Thus, in contrast to systems that use a conventional
computed tomography (CT) scanner in which the source of the imaging
beam itself moves, the x-ray beam produced by the e-beam scanner
610 moves through the region due to the action of the steering
device 616 on the electron beam. Because the source of x-rays is
not required to move (rather the x-ray beam itself is steered as a
result of the electron beam being steered by the steering device
616), the e-beam scanner 610 is able to scan the region much more
quickly than is possible with a conventional CT scanner system. For
example, the weight of a typical CT scanner generally prevents a CT
scanner from taking more than about two measurements of the imaged
region per second. In contrast, the e-beam scanner 610 may take
measurements fifty to one hundred times per second. Additionally,
the size of the e-beam scanner 610 allows it to fit into a gantry
with the source of irradiation energy to allow for concurrent
imaging and treatment. Finally, the positioning of the e-beam
scanner 610 and the source of irradiation energy at, for example,
an angle with respect to each other or tilted with respect to each
other, allows the portion of the region to be imaged with the x-ray
beam produced by the e-beam scanner 610 while also being irradiated
with the treatment beam 622 from the source of irradiation
energy.
[0060] The e-beam scanner 610 also includes a detector 618 that
senses x-ray radiation that passes through an imaged portion of a
region. The imaged portion may be a portion of a human or non-human
patient. For example, the imaged portion may be a suspected or
known tumor within a region that includes the patient's pancreas.
The detector 618 produces a representation of the sensed x-ray
radiation. As compared to the x-ray radiation produced by the
interaction of the electron-beam and the target material 615, the
sensed x-ray radiation has an intensity that is attenuated as a
result of passing through items the portion of the region. Thus,
the representation of the sensed x-ray radiation represents the
amount of attenuation caused by the portion of the region.
[0061] In implementations in which the detector 618 is a
scintillator, the detector 618 produces visible light having an
intensity proportional to the amount of detected x-ray radiation.
The e-beam scanner 610 also includes detector electronics 619 that
transform the representation of x-ray energy into a form that may
be processed by the processor 640. For example, the detector
electronics 619 may include a visible light sensor coupled to an
analog-to-digital converter that produces a digital value that
represents the amount of x-ray energy sensed by the detector
618.
[0062] The source of irradiation energy 620 provides a treatment
beam 622 to a region that is imaged by the e-beam scanner 610. The
system 600 includes both the e-beam scanner 610 and the source of
irradiation energy 620, and the e-beam scanner 610 and the source
of irradiation energy 620 are arranged such that the region may be
imaged by the x-ray imaging beam from the e-beam scanner 610 and
irradiated with the treatment beam 622 concurrently. For example,
the e-beam scanner 610 may be tilted such that the treatment beam
622 and the x-ray imaging beam are at an angle with respect to each
other.
[0063] The system 600 also includes the source of irradiation
energy 620. The source of irradiation energy 620 produces a
treatment beam 622. The source 620 also includes a beam controller
624. The beam controller 624 controls a property of the treatment
beam 622. The property of the treatment beam 622 may be a profile
of the treatment beam 622, an intensity of the treatment beam 622,
a location of the treatment beam 622 relative to a housing of the
source of irradiation energy 620, and/or a direction of propagation
of the treatment beam 622. The profile of the treatment beam 622
may be a spatial distribution of energy in a plane that is
perpendicular to the direction of propagation of the treatment beam
622. For example, the beam controller 624 may be a multi-leaf
collimator having movable leaves that block certain portions of the
treatment beam in order to shape the beam profile of the treatment
beam 622. The beam controller 624 also may cause the position
and/or the direction of propagation of the treatment beam 622 to
change. The beam controller 624 also may control the intensity (or
flux) of the treatment beam 622.
[0064] The system 600 also includes an I/O interface 630, a
processor 640, and an electronic storage 650. The electronic
storage 650 stores instructions, perhaps as a computer program,
that, when executed, cause the processor to communicate with other
components in the system 600. For example, the electronic storage
650 may store instructions that cause the beam controller 624 to
move the treatment beam 622. The processor 640 executes
instructions that cause the beam controller 624 to modify or
otherwise adjust a property of the treatment beam based on
information received from the detector 618. In another example, the
electronic storage 650 stores instructions that, when executed,
cause the processor 640 to generate images of the portion of the
region based on the representation of sensed x-ray radiation sensed
by the detector 618. The processor 640 also process commands
received from the I/O interface 630. The I/O interface 630 may be
any device or program that allows a user to interact with the
system 600. For example, the I/O device 630 may be a mouse, a
keyboard, a display, or a touch screen.
[0065] FIG. 7 is an example process 700 for modifying a property of
a treatment beam based on a characteristic of an object imaged by
an electron-beam scanner. The process 700 may be performed on a
processor such as the processor 640 discussed with respect to FIG.
6.
[0066] Data produced by an electron-beam scanner is received (710).
The data may be referred to as "first data." The first data is
received during a scanning period in which a portion of a region is
imaged by the electron beam scanner 610. The first data includes an
indication of a characteristic of the portion of the region. The
first data may be an image, a series of images, and/or a video
produced from the data sensed by the detector 618.
[0067] The region may be a portion of a patient's body, such as a
pancreas, that moves continuously due to normal bodily functions,
and the portion of the region may be a portion of the pancreas. As
discussed above, the imaging x-ray beam produced by the
electron-beam scanner 610 rapidly scans the region, which allows
moving organs and other moving structures to be imaged.
[0068] The indication of the characteristic of the portion of the
region may be data values that allow an analysis tool, such as an
edge detector or other signal processing technique, to process the
data to determine the characteristic.
[0069] The scanning period may be a time during which a patient is
imaged with the x-ray imaging beam and concurrently treated with
the treatment beam 622. The scanning period may be considered to be
a treatment session during which a patient is treated with the
treatment beam 622 to, for example, irradiate a tumor within the
patient. The treatment session may be a continuous treatment
session during which the patient remains in the region. The
scanning period may be contrasted with techniques in which images
of a portion of the region are generated and analyzed during an
imaging session and then used at a later time, separate from the
imaging session, to plan a treatment that uses the treatment beam
622.
[0070] A characteristic of the portion of the region is determined
from the first data (620). The characteristic is determined during
the scanning session. The characteristic may be a spatial
characteristic, such as size, shape, an outline or partial outline,
a profile, or an approximate shape that is the best match between
the imaged object and a library of pre-defined shapes. For example,
the characteristic may be a location, shape, and/or size of a
suspected tumor within a pancreas of a patient. In another example,
the shape of the tumor in a particular direction may be the
characteristic. The particular direction may be a two-dimensional
projection of the tumor and the organ that the tumor is within, on,
or near in the direction of propagation of the treatment beam
622.
[0071] An input derived from the characteristic is provided to the
irradiation source 620 (730). The input may be referred to as a
"first input." The first input is sufficient to cause the
irradiation source 620 to modify a property of the treatment beam
622. The property of the treatment beam 622 may be one or more of a
direction of propagation of the treatment beam 622, a beam profile
of the treatment beam 622, an intensity of the treatment beam 622,
a timing of the treatment beam 622, and a position of the treatment
beam 622. The first input may cause the source 620 to modify the
treatment beam 622 by causing the beam controller 624 to move
relative to the treatment beam 622. The first input is derived from
the characteristic such that the input causes the treatment beam
622 to be modified to match the characteristic. For example, the
characteristic may be a shape of a suspected tumor, and the
treatment beam 622 may be modified to have a profile that matches
the shape of the object. In another example, the treatment beam 622
may be modified by moving the treatment beam to follow, or track,
the position of a moving tumor. Such modifications may increase the
amount of irradiation energy that reaches the suspected tumor while
decreasing the amount of radiation reaching the surrounding healthy
tissue.
[0072] Data produced by the electron-beam scanner is received
during the scanning period (740). This data may be referred to as
second data. The second data is received after the first data, and
the second data includes a second indication of the characteristic
of the portion. The second data is received during the scanning
period but after the first data is received. The time between
receipt of the first data and the second data is determined by the
scan speed of the electron-beam scanner. For example, if the
electron-beam scanner receives data fifty times per second, the
second data may be received approximately 20 milliseconds after the
first data is received.
[0073] The characteristic of the portion is determined from the
second data during the scanning period (750). For example, in
implementations in which the position of the portion is the
characteristic, the position is determined at the first time
associated with the first data and the second time associated with
the second data. Thus, the imaged portion may be tracked over
time.
[0074] An input derived from the characteristic determined from the
second data is provided to the source 620 (760). This input may be
referred to as a second input. The second input is sufficient to
cause the source 620 to modify the property of the treatment beam
622 to account for the characteristic determined from the second
data, and the second input is provided during the scanning session.
For example, the characteristic may be a position of a tumor in a
patient's pancreas, and the second input may be an input sufficient
to cause the treatment beam 622 to move to follow the tumor as it
moves with the pancreas. Because of the features of the
electron-beam scanner 610, the treatment beam 622 is modified
during the scanning session. Thus, the treatment of the patient
with the irradiation beam is planned in real-time, or near-real
time, while the patient is imaged. In some implementations, the
first and second input are formatted such that the inputs are
compatible with inputs that are produced by a standard CT
scanner.
[0075] The techniques can be implemented in digital electronic
circuitry, or in computer hardware, firmware, software, or in
combinations of them. The techniques can be implemented as a
computer program product, i.e., a computer program tangibly
embodied in an information carrier, e.g., in a machine-readable
storage device, in machine-readable storage medium, in a
computer-readable storage device or, in computer-readable storage
medium for execution by, or to control the operation of, data
processing apparatus, for example, a programmable processor, a
computer, or multiple computers. A computer program can be written
in any form of programming language, including compiled or
interpreted languages, and it can be deployed in any form,
including as a stand-alone program or as a module, component,
subroutine, or other unit suitable for use in a computing
environment. A computer program can be deployed to be executed on
one computer or on multiple computers at one site or distributed
across multiple sites and interconnected by a communication
network.
[0076] Method steps of the techniques can be performed by one or
more programmable processors executing a computer program to
perform functions of the techniques by operating on input data and
generating output. Method steps can also be performed by, and
apparatus of the techniques can be implemented as, special purpose
logic circuitry, e.g., an FPGA (field programmable gate array) or
an ASIC (application-specific integrated circuit).
[0077] Processors suitable for the execution of a computer program
include, by way of example, both general and special purpose
microprocessors, and any one or more processors of any kind of
digital computer. Generally, a processor will receive instructions
and data from a read-only memory or a random access memory or both.
The essential elements of a computer are a processor for executing
instructions and one or more memory devices for storing
instructions and data. Generally, a computer will also include, or
be operatively coupled to receive data from or transfer data to, or
both, one or more mass storage devices for storing data, such as,
magnetic, magneto-optical disks, or optical disks. Information
carriers suitable for embodying computer program instructions and
data include all forms of non-volatile memory, including by way of
example semiconductor memory devices, such as, EPROM, EEPROM, and
flash memory devices; magnetic disks, such as, internal hard disks
or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM
disks. The processor and the memory can be supplemented by, or
incorporated in special purpose logic circuitry.
[0078] A number of implementations of the techniques have been
described. Nevertheless, it will be understood that various
modifications may be made. For example, useful results still could
be achieved if steps of the disclosed techniques were performed in
a different order and/or if components in the disclosed systems
were combined in a different manner and/or replaced or supplemented
by other components. Accordingly, other implementations are within
the scope of the following claims.
* * * * *