U.S. patent application number 11/903859 was filed with the patent office on 2009-03-26 for dedicated breast radiation imaging/therapy system.
Invention is credited to Kenneth Brooks, Andrew P. Smith, Jay A. Stein.
Application Number | 20090080602 11/903859 |
Document ID | / |
Family ID | 44661296 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090080602 |
Kind Code |
A1 |
Brooks; Kenneth ; et
al. |
March 26, 2009 |
Dedicated breast radiation imaging/therapy system
Abstract
System, apparatus and methods specialized for breast and related
tissue radiation therapy and imaging of a prone patient but also
usable for supine patient if desired or needed. A special treatment
radiation source such as a LINAC unit generates radiation of types
and energy ranges specifically matched to breast tissue. Any one or
more of several imaging technologies may be used to localize the
tissue to be irradiated and to generate information for therapy
planning, adjustment, and verification.
Inventors: |
Brooks; Kenneth; (Knoxville,
TN) ; Stein; Jay A.; (Boston, MA) ; Smith;
Andrew P.; (Lexington, MA) |
Correspondence
Address: |
Cooper & Dunham, LLP
30 Rockefeller Plaza, 20th Floor
New York
NY
10112
US
|
Family ID: |
44661296 |
Appl. No.: |
11/903859 |
Filed: |
September 24, 2007 |
Current U.S.
Class: |
378/20 ; 378/37;
378/65 |
Current CPC
Class: |
A61B 6/502 20130101;
A61N 5/1049 20130101; A61N 5/10 20130101; A61N 5/1082 20130101;
A61N 2005/1061 20130101; A61N 2005/1097 20130101; A61B 6/032
20130101; A61B 6/4258 20130101; A61N 2005/1058 20130101; A61N
5/1081 20130101; A61B 6/0414 20130101; A61N 2005/1087 20130101 |
Class at
Publication: |
378/20 ; 378/37;
378/65 |
International
Class: |
A61N 5/10 20060101
A61N005/10 |
Claims
1. A method of treating breast-related tissue of a prone patient
comprising: placing the patient on a surface of a patient table in
a prone position, with a patient's breast protruding downward from
the table surface through an opening or into a depression in the
table; irradiating the breast-related tissue with treatment
radiation from a source mounted for movement about an upwardly
extending axis to emit a treatment radiation beam that originates
below the table surface; and selectively angling the beam to
irradiate with primary radiation portions of the prone patient's
breast-related tissue that are above the table surface.
2. A method as in claim 1 including imaging the patient placed on
the table, before said irradiating step, with an imaging apparatus
keyed to a spatial frame of reference to which said source also is
keyed, to develop, adjust or verify a radiation treatment plan.
3. A method as in claim 2 in which said imaging comprises
three-dimensional (3D) imaging.
4. A method as in claim 3 in which said 3D imaging comprises one or
more of ultrasound, x-ray imaging, and imaging using radiation
emitted from within the patient.
5. A method as in claim 1 including introducing into the patient
one or more sensors for at least one of position and radiation dose
and utilizing said sensors in at least one of developing,
adjusting, and verifying a radiation treatment plan for the
patient.
6. A method as in claim 1 including interacting with a prone
patient's breast for imaging and radiation treatment with a device
that both tends to pull the breast from the patient's chest wall
and to secure the breast in a selected position.
7. A method as in claim 1 including imaging the patient's breast
with CT scanning while the patient is in the position on the
patient table in which said irradiating is carried out.
8. A method as in claim 1 including detecting treatment radiation
delivered to a target volume in or at breast-related tissue of the
patient and delivering information regarding said detecting to one
or more utilizing stations associated with the treatment
system.
9. A method as in claim 1 including moving the source of the
radiation to selectively irradiate patient tissue from a number of
selected directions and selectively varying the distance between
the source of the radiation and target tissue.
10. A system for radiation treatment of breast-related tissue
comprising: a patient table having an upper surface for supporting
a patient, said table having a selectively revealed opening or
depression for a patient breast to extend downwardly from the
patient table surface when the patient is in the prone position on
said table; a therapy radiation source selectively emitting therapy
radiation and a mounting structure supporting the source and
selectively moving the source in a first motion in which it
irradiates a first target volume with a primary radiation beam that
has a centerline below the table surface and in a second motion in
which it irradiates a second target volume with a with primary
radiation beam that has a centerline angled from the horizontal and
intersecting the table surface.
11. A system as in claim 10 in which the first target volume is at
a downwardly protruding breast of a patient in the prone position
on the patient table and the second target volume is at the
patient's axilla.
12. A system as in claim 10 further the mounting structure includes
structure supporting the source for motion in which the source
emits a therapy beam from a location above the table surface to
directly irradiate breast-related tissue of a patient in the supine
position on said table surface.
13. A system as in claim 10 including a table support and a an
interlock mechanism configured to releasably secure the table at a
selected position relative to a system frame of reference in which
the source is at a known position, said interlock mechanism also
configured to mate with a separate imaging device operative to
generate imaging information for a radiation treatment plan for the
patent, said treatment plan being spatially referenced to an
interlocked position of the table to the imaging device.
14. A system as in claim 10 including a CT scanner mounted in the
system and selectively brought in position for CT imaging of a
patient in the prone position on said patient table.
15. A system as in claim 10 including an imaging system mounted in
a known frame of reference relative to the therapy radiation source
for selectively imaging breast-related tissue.
16. A system as in claim 15 in which said imaging system
selectively provides 2D images of said tissue.
17. A system as in claim 15 in which said imaging system
selectively provides 3D imaging information of said tissue.
18. A system as in claim 10 in which said mounting structure
includes a positioning mechanism selectively varying a distance
between said source of therapy radiation and said target
volume.
19. A system as in claim 10 including a control unit directing the
radiation source in accordance with previously generated treatment
plans.
20. A system as in claim 10 in which said mounting structure
comprises a rotating plate support on which said therapy radiation
source is mounted for rotation about an axis extending along a
length of said patient table.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to International application No.
PCT/US07/017470 filed Aug. 3, 2007, claiming the benefit of
provisional application Ser. No. 60/835,803 filed Aug. 3, 2006.
This patent specification incorporates by reference the content of
each of said earlier-filed applications.
FIELD
[0002] This patent specification is in the field of radiation
therapy and associated imaging and therapy
planning/adjustment/verification, and specifically pertains to
dedicated, specialized radiation therapy of a patient's breast and
associated imaging and planning procedures.
BACKGROUND
[0003] Radiation therapy has long been used in medicine. Typically,
high energy radiation from sources such as linear accelerators and
radioisotopes is used, especially in whole-body, external beam
systems where the radiation may need to penetrate a significant
amount of tissue in order to reach the target volume and attain
within the target volume the prescribed therapeutic dose level and
fractionation scheme. The irradiation of normal tissue is a
necessary physical consequence of all modes of radiotherapy and
typically becomes the limiting factor in any given patient's
therapy regimen. In procedures that use radiation sources inside
the patient's body, a similar challenge is the undesirable but
unavoidable exposure of normal tissue. Conventional, whole-body,
external beam systems can be used for breast therapy as well but
their large, whole body geometry tends to lead to undesirable
irradiation of significant amounts of healthy tissue. Also, whole
body, external beam systems may be designed to irradiate at energy
levels that are not optimized for breast tissue. In order to reduce
normal tissue irradiation and achieve sufficient target volume
dose, efforts have been made to find other approaches for breast
radiation therapy, leading to methods that include, in addition to
the orthovoltage radiation treatment disclosed in said
earlier-filed patent applications, proposals by others such as (1)
internal breast brachytherapy which involves inserting catheters or
needles in the breast and placing radioactive substances in or
through the catheters or needles or using radioactively coated
needles, (2) surgically implanting a balloon in the breast and
selectively delivering radioactive material to the balloon through
a catheter, (3) surgically positioning a miniature x-ray tube
inside the breast, (4) external stereotactic brachytherapy that
involves compressing the breast between two sets of conforming
channels through which a radioactive substance is placed in close
proximity to the breast, (5) using orthovoltage radiation from an
external kilovoltage x-ray source that irradiates the breast from
the side or possibly through a purposely designed surgical opening
in the tissue, (6) using a LINAC radiation source that rotates in a
horizontal plane to irradiate a downwardly protruding breast of a
patient on a table with an opening for the breast, and imaging the
breast with that source or an adjunct source, and (7) combining a
radioactive substance with a biologically active material designed
to uptake selectively in the breast tissue where it decays and
provides a therapeutic dose (such as monoclonal antibodies) or a
substance which causes the tumor to be more radiosensitive during
the treatment.
[0004] An external beam radiation therapy treatment typically
involves therapy planning in which the location and perhaps other
characteristics of a lesion or other target volume to be treated or
avoided and monitored are identified by one or more imaging
technologies such as ultrasound, X-ray computed tomography, static
and dynamic planar imaging, nuclear medicine imaging, and magnetic
resonance imaging. Information from these imaging modalities is
used in computer processing to develop a treatment plan for the
directions, energies, and durations of the therapy radiation beams
and the number and frequency of the treatment sessions. In
addition, before each radiation therapy session images of the
lesion and/or other target volume may be taken to check the
position of the target volume and other tissue relative to the
geometry of the radiation therapy system, and various positioning
aids may be used in the therapy system to verify and maintain a
desired geometric relationship between the radiation treatment
beam(s) and the target tissue.
[0005] See, for example, H. E. Johns & J. R. Cunningham. The
Physics of Radiology, Ch. Thomas, 1983; S. C. Formenti,
External-Beam Partial-Breast Irradiation, Seminars in Radiation
Oncology, Elsevier 2005, 82-99; G. Jozsef, G. Luxton, S. C.
Formenti, Application of radiosurgery principles to a target in the
breast, A dosimetric study, Med. Phys. 27 (5). May 2000, 1005-1010;
O. Gayou, D. S. Parda, M. Miften, Patient dose and image quality
from mega-voltage cone beam computed tomography imaging, Med. Phys.
34 (2). February 2007, 499-506.
[0006] Despite such advances in radiation therapy systems,
including for breast radiation, it is still desirable to improve
breast radiation therapy by making it more effective and
efficient.
SUMMARY OF THE DISCLOSURE
[0007] Disclosed is a dedicated system for radiotherapy of the
breast and related tissue of a patient in the prone position, with
radiation beams that can rotate below the patient about a vertical
axis but in addition can rotate about an axis angled to the
vertical to treat breast-related tissue such as axillary lymph
nodes without turning the patient over. Maintaining the patient in
the same prone, breast-pendulous position can ensure good
registration between the treatment beams and target volume, and
good consistency with treatment plans for both breast and related
tissue. Further, the system can include a mode in which the patient
can be treated in the supine position, if desired or if called for
by special circumstances. The system also includes imaging
functionalities that share a spatial frame of reference with the
treatment functionalities, whether or not they also share
components, and can verify and/or adjust a treatment plan or
generate a treatment plan through two-dimensional (2D) or
three-dimensional (3D) imaging/planning. The distance between the
radiation source for treatment/imaging and the target volume can be
varied if desired so the radiation source can move about the target
volume or some other center rather than about a fixed isocenter.
This can be done by one or both of source motion and patient table
motion. The system can further include sensors/transmitters that
can be implanted or otherwise secured in or to the patient, or can
be otherwise fixed relative to a system frame of reference, to
verify the position of a target volume or other tissue relative to
the radiation beam(s) and/or to measure the radiation dose in two
or three dimensions. The sensors/transmitters preferably include
data storage and/or transmission functionalities to provide
information to the system, preferably on an essentially real time
basis. The patient can be on a patient table or couch that fits
both the treatment/imaging system and conventional imaging
modalities such as CD scanners so that the patient can remain in or
conveniently and accurately resume the same position, such as the
prone position with a breast protruding downwardly through an
opening or into a depression of the patient table or couch, when
imaged for treatment planning at one system and then when
positioned for treatment/verification at another system. The
patient can be positioned on the table and couch in the prone
position with the protruding breast immobilized in an effort to
maintain or accurately resume its position relative to the table or
couch, and can be imaged in a CT scanner for radiation planning and
then later positioned at the disclosed system for treatment in
which the position of the breast or other target tissue relative to
the system frame of reference is known from the information
provided from treatment planning and the fact that the position of
the table or couch relative to the treatment system also is known,
e.g., from mechanical, optical, mechanical or other table mounting
interlocks. The imaging functionalities of the disclosed system can
include 2D and/or 3D imaging systems such as portal imaging using
the treatment radiation source, an x-ray imaging using components
mounted in known relationship to the system spatial frame of
reference, nuclear medicine imaging (including metabolic activity
imaging) using detectors also mounted in the same system as the
radiation treatment source and in a known spatial relationship with
the system frame of reference, ultrasound imaging with transducers
maintained in known positions in the system frame of reference,
and/or other imaging modalities. Suction or other devices can be
used to pull breast tissue away from the chest wall as needed
and/or to stabilize the breast for imaging/treatment. The system
can be used for traditional treatment plans that use fractional
doses over a longer period of time such as a number of weeks or for
partial breast irradiation that typically treats only a part of the
breast (e.g., a lumpectomy site) but over a shorter period of time
such as once or twice a day for five days. Also disclosed are
methods of using the system and methods of imaging, treatment
planning/verification/adjustment and radiation treatment.
[0008] In one non-limiting embodiment the system comprises a table
or couch for the patient to lie prone with at least one breast
protruding downwardly through an opening or extending into a
depression in the table or couch. Preferably a positioning device
is used to maintain a reasonably consistent and stable position of
the breast relative to the patient table or couch and the imaging
and treatment system spatial frame of reference and, if desired, to
help pull tissue away from the chest wall. In an imaging mode, the
system provides information for identifying the position of the
breast, the target volume in the breast and/or of some other tissue
relative to both the system geometry and pre-treatment patient
geometry by utilizing imaging technologies such as one or more of
x-ray planar and computed tomography or tomosynthesis, nuclear
medicine, ultrasound, other imaging modalities, and
position-indicating and/or monitoring devices that can be implanted
in or otherwise secured to or near the tissue of interest and are
specifically designed to work within the confines of the system and
patient geometry (and preferably can store and/or transmit
information regarding position and dose). This pre-treatment
imaging takes place before at least the first treatment session but
may be repeated before additional treatment sessions, and can also
be used to identify or estimate other characteristics such as shape
and size of a lesion or other target volume parameters related to
the tissue along intended therapy radiation paths and also to
identify critical structure volumes whose unintended irradiation is
to be minimized, characteristics of other portions of the breast
and perhaps of other anatomy, and the like.
[0009] In a treatment planning/adjustment/verification mode, the
system uses information obtained from other imaging modalities
and/or information from the imaging mode of the system disclosed in
this patent specification to plan treatment or at least to
verify/adjust treatment plans and/or verify the position of the
lesion or other target volume and/or of other body parts relative
to system and patient geometry. In a radiation therapy mode of the
system disclosed in this patent specification, a therapy radiation
source below the patient table or couch moves about the downwardly
extending breast of a patient in the prone position and emits
radiation in energy ranges that are uniquely suited to
breast-related radiation treatment. Importantly, the therapy
radiation source can move not only in a horizontal plane (e.g.,
about a vertical axis) but also in other planes (e.g., about a
non-vertical axis) to irradiate breast-related tissue such as the
patient's axilla, target volumes that are very close to the chest
wall, and other lymph nodes away from the breast. Also importantly,
the therapy radiation source can rotate or otherwise move about the
lesion or other target volume or about other loci to direct
radiation along paths that maintain a low skin dose. The system
directs and otherwise controls the radiation, preferably in
accordance with current or updated treatment plans.
[0010] Preferably, the therapy radiation source is a special linear
accelerator (Linac) that has two important characteristics--it
emits treatment radiation that can be uniquely suited to
breast-related tissue, and it is sufficiently compact to be mounted
below the prone patient table for movement about a patient's breast
such as in a horizontal plane and also for movement about the
breast such as in a plane at an angle to the horizontal in order to
direct primary radiation at other target tissue that may be
associated with the breast.. Thus, the source can rotate about a
vertical axis and/or about an axis that extends upwardly but at an
angle to the vertical to enable therapy radiation to be directed to
target volumes outside the prone patient's breast if desired, such
as at or near the patient's chest wall or the patient's axilla. In
addition, if desired the therapy radiation source can be moved
above the patient or to other positions suitable for irradiation a
supine patient. The linear accelerator produces a maximum energy
that can be set at a value, or can vary, in the range of about 1-10
MeV Bremstrahlung photons, and preferably about 4-6 MeV. As an
alternative example, the treatment radiation can be charged
particles including but not limited to particles such as electrons,
protons, and deuterons. Electrons for a treatment beam can come
from the linear accelerator source when the conventional
Bremstrahlung target is removed and appropriate bean shaping fields
are provided. Other particles for a treatment beam can come from
other accelerating sources known in high-energy physics.
[0011] The imaging system preferably uses penetrating radiation
from an external source but may use, instead or in addition,
radiation emitted from the breast and/or related tissue, such as
from a radiation emitting substance injected or otherwise
introduced into the patient's body, and can use ultrasound imaging.
In one example, portal imaging is used in which a Linac-based
source also provides imaging radiation, and an imaging detector
that is suitable for such high-energy radiation generates the
image(s). Different energy levels of penetrating radiation from the
source may be used for imaging versus therapy, if desired.
Alternatively, a source different from that used for therapy can be
used to provide imaging radiation. As a non-limiting example,
imaging radiation can come from an x-ray source of the type
typically used in x-ray mammography or for imaging the chest, and
the imaging detector can also be of the type used in x-ray
mammography or chest radiography, and preferably is a flat panel
detector of the type commercially available from the common
assignee, Hologic, Inc. If the source of the imaging radiation is
internal, suitable imaging detectors are used, such as SPECT, PET,
or nuclear medicine imaging detectors. Another imaging modality
that can be used is ultrasound, preferably carried out in a manner
that also provides information to positionally relate the imaged
tissue with the geometry of the therapy radiation system and the
patient's reference frame established before therapy and updated as
needed during the course of therapy. A CT scanner suitable for
breast imaging may be included in the system. Only one of the
imaging modalities identified above may be used, or a combination
of two or more imaging modalities can be used, to provide
information for therapy planning, updating, and verification.
Preferably, the imaging system also moves, e.g., rotates under the
prone patient's table, about a vertical or non-vertical axis, and
can be moved to the patient level or above the patient if desired
to image a patient who is in the prone or other position, and
preferably the rotation or other motion centers on the lesion or
other target volume. Preferably, the imaging modality produces
three-dimensional information, such as information based on
tomosynthesis, CT scanning, stereotactic imaging, 3D ultrasound
imaging, or other 3D imaging modalities.
[0012] The imaging information is used to generate both
traditional, static, forward planned treatment plans as well as
inverse planned, dynamic intensity modulated treatment plans using
state-of-the-art integrated optimization methods that can be based
on known treatment planning technology used for whole-body
radiation therapy systems, such as those commercially available
from Varian Medical Systems of Palo Alto, Calif., Philips Medical
Systems of Andover, Mass., and CMS Inc. of St. Louis, Mo., but
taking into account the unique geometry of the breast
therapy/imaging system disclosed in this patent specification and
its other unique parameters such as optimized multileaf collimator
leaf sizes designed for targeting smaller breast lesions or other
breast-related target volumes rather than the typically larger
target volumes addressed by whole body systems, and the photon or
particle energy levels which are also closely matched to
breast-related tissue.
[0013] The patient's breast can be immobilized and maintained in
position for pre-treatment planning in one or more imaging system
and for treatment by devices that include but are not limited to
thermoplastics, vacuum fixation bags, foam padding, appendage
fixation devices, cones, vacuum and/or adhesives applied to such
cones, or other means. Devices of this nature are proposed, e.g.,
by MedTec of Orange City, Iowa under the trade name Horizon
Breastboard and by Varian Medical Systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The features of the subject matter of this disclosure can be
more readily understood from the following detailed description
with reference to the accompanying drawings wherein:
[0015] FIG. 1 illustrates a top view of an embodiment comprising an
integration of a breast therapy system and multiple breast imaging
systems.
[0016] FIGS. 2a-2d illustrate a top view of the therapy system of
FIG. 1 in several different positions of a therapy radiation
source.
[0017] FIG. 3 illustrates a top view of a patient table for use in
the system of FIG. 1.
[0018] FIG. 4a illustrates a side view of a patient table and a
center of rotation of the radiation source about an upwardly
extending axis.
[0019] FIG. 4b illustrates a side view of a patient table and a
center of rotation of the radiation source about a laterally
extending axis.
[0020] FIG. 5a illustrates a perspective view of the
imaging/therapy system in relation to a desired isocenter of
rotation.
[0021] FIG. 5b illustrates a side view of the system.
[0022] FIG. 6a is a schematic illustration of an example of a
radiation therapy and imaging system in side view, and FIG. 6b is a
schematic illustration of the system in a front view.
[0023] FIG. 7 is is a schematic illustration of a system in side
view that includes CT imaging provisions.
DETAILED DESCRIPTION
[0024] In describing preferred embodiments, specific terminology is
employed for the sake of clarity. However, the disclosure of this
patent specification is not intended to be limited to the specific
terminology so selected and it is to be understood that each
specific element includes all technical equivalents that operate in
a similar manner. In addition, a detailed description of known
functions and configurations will be omitted when it may obscure
the subject matter of the present invention.
[0025] As illustrated in FIG. 1, a non-limiting example of the
system comprises a table or couch 101 that is especially adapted to
support a patient in the prone position but may also be used to
support a patient in other positions such as in the supine
position. FIG. 1 also illustrates one or more imaging systems
discussed below in more detail for localizing and identifying a
lesion or abnormality or target volume, a radiation source such as
a special Linear Accelerator (LINAC) 105 for producing therapy
radiation, and a motorized cantilevered stand 106. For clarity, the
table is illustrated in FIG. 1 with a cutout 109 to allow
visualizing the components that are below the table. Preferably the
LINAC device 105 is a compact version capable of producing
penetrating radiation uniquely suited to breast-related tissue
rather than optimized for whole-body radiation therapy. Preferably,
the imaging and therapy systems move about the patient's breast,
preferably though not necessarily in rotation, and preferably the
motion is centered on the lesion or target volume for therapy
irradiation. However, as discussed below the system may include
provisions for moving the therapy and/or imaging components in a
manner suitable for patients in other patient positions, such as
the supine patient position.
[0026] The imaging systems in FIG. 1 example may include: an x-ray
system that uses an x-ray source 102 and x-ray digital imaging
detector (flat panel) 120, a stereotactic x-ray imaging system
where two x-ray sources 102 and 103 are used with respective x-ray
imaging panels 120 and 113 (or one set of a source such as 102 and
a detector such as 120 is moved to one position for one x-ray image
and another position for another image), PET or SPECT imaging
panels or ultrasound transducers 104, combinations of two or more
of the imaging systems identified above, or other imaging systems.
If an x-ray imaging system is used, it can use only one, or both,
of sources 102 and 103 and x-ray detector panels 113 and 120, to
image the patient's breast or other patient tissue. Imaging source
102 and x-ray panel 120 are mounted to move about the breast as a
unit, to image the breast from different angles. If source 103 and
panel 113 are used, they also rotate or otherwise move as a unit,
and if both source/panel sets are used, the two sets can rotate as
a unit or individually. In each case, the motion can be about a
center 107 that can be at the lesion or target volume or some other
center. The x-ray imaging system(s) may be used to derive
projection tomosynthesis image data, for example by using motion
and image reconstruction as disclosed in commonly assigned U.S.
Pat. Nos. 7,245,694, 7,233,005, 7,123,684, 7,122,803, 6,851,851,
and 6,282,264, or to derive stereotactic information, for example
as discussed in U.S. Pat. No. 5,803,912 or U.S. Patent Publication
2004/0171933 A1.
[0027] FIGS. 2a-2d are top views of the system that illustrate
examples of the range of positions of the therapy system in
relation to patient table 101 (that again is shown with cutout 109
to allow seeing components below the table). A motorized stand 106
supports table 101 for up-down motion and, if desirable, for motion
along and across the length of the table, and also can support the
imaging and therapy systems for rotation in a circle 111
representing a preferred 360 degree range of rotation of LINAC 105
and of the imaging system(s) around a selected center 107. If
portal imaging is used, a portal imaging detector 108 and the LINAC
device 105 can move as a unit for imaging.
[0028] FIG. 2a illustrates the LINAC device at 0.degree. relative
to prone table 101 and isocenter 107. Illustrative cutout 109
reveals the LINAC source 105, center 107, and a radiation detector
108. FIG. 2b illustrates LINAC source 105 at 180.degree. relative
to patient table 101 and center 107. Illustrative cutout 109
reveals center 107 and detector 108. FIG. 2c illustrates LINAC
source 105 at approximately 45.degree. relative to table 101 and
center 108. Illustrative cutout 109 reveals center 107 and detector
108. FIG. 2d illustrates LINAC source 105 at 270.degree. relative
to prone table 101 and center 107. Illustrative cutout 109 reveals
center 107 and detector 108. In a non-limiting example, circle 111
representing the diameter and range of rotation of LINAC source 105
and imaging detector 108 preferably has a diameter of approximately
three meters. Stand 106 preferably extends approximately 1 meter
from a wall.
[0029] FIG. 3 illustrates additional features of patient table 101
as seen in top view. Table 101 comprises left and right removable
mesh panels 303, 304 that cover respective left and right openings
in the table. When a mesh panel is removed from the table, the
opening allows a patient's breast to extend downwardly for imaging
and/or radiation therapy. The panels are designed to be replaced by
a breast stabilizing aide, such as an aide made of an "Aquaplast"
material or comparable material forming a semi-rigid thermoplastic
surface around a breast. The system operating in an imaging mode
with all of the associated modalities can be used to help establish
the stabilizing aide and correlate what will become a semi-rigid
surface of the thermoplastic material to the breast, the target
volumes and the system reference frames. Additional or alternative
stabilizing aides such as other thermoplastics, vacuum fixation,
personal positioning cups, or variations of positioning boards and
coaches may be employed in the radiotherapy apparatus disclosed
herein.
[0030] The stabilizing aide(s) or combinations thereof preferably
facilitate immobilizing a breast for imaging so that the target
volume can be accurately located in relation to patient and system
geometry and the lesion or other radiation target volume can then
be given a planned radiotherapy dosage. The use of stabilizing
aides described herein and variations thereof can assist the
radiotherapy system in providing consistent and precise irradiation
of a patient's anatomy on a daily basis. The stabilizing aides
described herein are relatively inexpensive and can be
re-fabricated as needed during the course of therapy for clinical
(anatomy changes, adema, etc) or patient comfort requirements. As
in the case of the stereotactic imaging and biopsy table available
from the common assignee under the name MultiCare, the table
surface can be shaped, originally or with the help of special
pillows, to provide patient comfort and to extend the appropriate
anatomy as much as possible below the patient table.
[0031] Additionally, implantable or otherwise attachable position
and dose sensors for use within or near a patient's breast or other
anatomy can be utilized to further increase the accuracy and
effectiveness of an individualized patient radiotherapy treatment
plan, optionally in combination with one or more breast stabilizing
aides. There are implantable position sensors capable of
communicating anatomical positioning information, an example of
which is available from CALYPSO Medical. One or more implantable
position sensors could be placed within a patient's breast and
surrounding anatomy and using wireless technology communicate with
an embodiment of the radiotherapy system. The combination of
implantable position sensors in communication with an embodiment of
the radiotherapy system using one or more imaging modalities can
accurately determine patient geometry in relation to the
radiotherapy system geometry thereby allowing accurate and daily
irradiation of a patient concurrent with an individualized patient
radiotherapy treatment plan.
[0032] Implantable or otherwise attachable dose monitoring sensors
such as those available from Sicel Technologies, Inc. can be used
within an embodiment of the disclosed radiotherapy system in
addition to or optionally independent of implantable position
monitors. Implantable monitoring sensors such as those from Sicel
Technologies, Inc. can collect and store data related for example
to tumor cell kinetics and physiology, pH or oxygen levels,
temperature, uptake and retention of chemotherapeutic agents, as
well as the radiation dose delivered to a region of a patient's
anatomy. Said monitoring sensors then use wireless technology to
communicate collected data to receivers located outside a patient's
body. In a preferred embodiment of the radiotherapy system, one or
more implantable monitors can be used in a non-limiting example as
radiation dose monitors and can be implanted in a patient at or
near the lesion to be treated with therapeutic radiation and
optionally surrounding tissue as well. Implanted radiation dose
monitors are able to communicate to the radiotherapy system
precisely what radiation dose is striking a patient's anatomy.
Precise internal radiation dose information from implanted dose
monitors can accurately provide dose information to doctors,
physicians, and embodiments of the radiotherapy system herein
thereby limiting over- or under-irradiation of a patient's anatomy
and aiding in accurate and consistent daily treatment according to
a patient's radiotherapy treatment plan. Stray radiation possibly
striking other areas of a patient not intended to be irradiated can
be monitored by properly implanted or otherwise secured dose
monitors thereby increasing patient safety. Both position and dose
monitors described herein are small devices capable of implantation
using commercially available biopsy systems such as from the Suros
Corporation and methods in current clinical use.
[0033] FIG. 3 further illustrates degrees of freedom of the motion
of patient table 101. The four directional arrows 302 represent the
direction of motions along which motorized stand 106 can move prone
table 101 (in addition to any up-down or tilting motion). In a
preferred but non-limiting embodiment, table 101 can move
approximately 10 centimeters in any direction from a resting
position in the horizontal xy-plane parallel the floor. X and Y
directions are shown by axis 305. Stand 106 also can be configured
to move the patient table in the vertical position, and/or to tilt
table 101, if desired. LINAC source 105 is shown in FIG. 3 at a
180.degree. position relative to table 101. Arc 306 is placed in
FIG. 3 for illustrative purposes to exemplify a curved direction of
motion of LINAC source 105 around table 101, preferably about an
isocenter of the system (not shown). In a non-limiting example, the
rotational movement of LINAC source 105 can be combined with the
vertical and horizontal movement of prone table 101 by motorized
stand 106 allowing desired target volumes of patient's breast and
surrounding tissue to be imaged and receive appropriate levels of
therapeutic radiation in accordance with an individual patient's
radiation therapy plan.
[0034] FIG. 4a is a side view of an example of the system, with
LINAC source 105 at a 180.degree. position around center 107. A
radiation beam centerline 403 is shown of a shaped beam, e.g. a
conical beam, exiting LINAC source 105, passing through center 107
and impinging on imaging detector 108. An additional feature is an
optional beam blocker 608 that substantially stops primary photon
energy that passes through imaging detector 108. Table 101, which
is not shown to scale in terms of thickness, further comprises
rounded openings 401 for a patient's breast, directly above center
107. Z-Y directional axis 402 is illustrated to show both the
z-direction and y-direction of the system relative to the side view
illustrated in FIG. 4a. A motion control 610 supports source 105,
imaging detector 108, and beam blocker 608 and provides interface
electrical and electronic connections between source 105, detector
108, and a sub-system 612 that serves as a system control and for
processing and displaying data. Unit 610 and its connections to
other units are shown schematically but it should be understood
that the unit typically contains motors and associated components
that impart the desired motions to source 105, imaging detector
108, and beam blocker 608, including motion in the horizontal plane
(flat or curved) about center 107, tilting so that the motion about
center 107 is in a plane (flat or curved) angled to the horizontal
and such that at least source 105 can be at the level of or above
patient table 101, and translating motion that moves center 107 to
the left or to the right or up or down as seen in FIG. 4a. The
schematic connections shown between unit 610 and source 105 and
imaging detector 108 represent both mechanical and
electrical/electronic two-way communication. The two-directional
arrows in the connections to units 105, 108, and 608 schematically
illustrate telescoping mechanism that can be motor-driven, e.g., by
fluidic or electrical motors, up and down along the lengths of the
mechanical supports. Unit 612 need not be under table 101; in fact,
typically it is not in the same room as the therapy/imaging system.
For clarity, the imaging systems illustrated in FIG. 1 are not
shown in FIG. 4a but it should be understood that they can be
mounted to and electrically/electronically connected to unit 610 in
a manner in which their positions are known relative to the system
frame of reference. Alternatively, they can be mounted and
otherwise connected to a separate motion control and interface
configured to move them in a way that does not interfere with the
therapy radiation and portal imaging components. One of the motions
of source 105 under patient table 105 about the patient's breast
typically is in a horizontal plane; however, provisions can be made
for deviations from a motion in a flat plane, such as for motion in
which the vertical elevation of source 105 varies during its motion
about the breast. In addition, as discussed in greater detail in
connection with FIG. 4b below, source 105 can move to positions at
the level of, or above, patient table 101.
[0035] FIG. 4b is similar to FIG. 4a but illustrates an additional
capability of a preferred embodiment of the disclosed radiotherapy
system. For clarity, units 610 and 612 and the mechanical and
electrical/electronic connections of FIG. 4a are not shown in FIG.
4b but it should be understood that they are a part of the system
as it would be seen in this configuration as well. During
radiotherapy treatment of a breast or related anatomy, it is
occasionally desirable to irradiate lymphatic systems and
anatomical tissue located outside of the breast tissue hanging
pendulant through an opening or into a depression in table 101. In
these cases, an example being when breast cancer metastasizes, it
is desirable to image and irradiate the lymphatic systems
associated with a breast including axillary, parasternal, and
pectoral nodes located in or near a patient's armpit area,
collarbone area, or axillae. In these circumstances, the dislcosed
imaging and therapy system can optionally tilt radiation source 105
such that a centerline of a therapy radiation it emits is at an
angle to the horizontal, e.g. at 45.degree.-55.degree.. As
illustrated in FIG. 4b (where the angle is greater for clarity of
illustration), an emitted radiation beam centerline 403 can pass
upwards through a patient's armpit area and therapeutically
irradiate lymphatic tissue and surrounding anatomical structures as
desired. For this purpose, source 105 is mounted for movement about
center 107 about a non-vertical axis, in a non-horizontal plane
that can be flat or curved, and one or both of source 105 and
detector 108 can be mounted for movement toward and away from
center 107, along radiation centerline 403, and thus toward or away
from a target volume Radiation detector 108 can be moved into a
position above patient table 101, to remain perpendicular to the
radiation beam centerline 403. In this case it is not necessary for
the radiation beam centerline 403 to pass through an isocenter of
the system. The precise pathway of the therapeutic radiation
emitted from LINAC device 105 is determined by the treatment plan
for a particular patient. Although not shown in FIG. 4b, optional
photon blocker 608 also can be moved from below prone table 101 and
positioned behind radiation detector 108 to absorb primary
radiation still passing through detector 108.
[0036] FIG. 5a illustrates a top view of a portion of the
radiotherapy system comprising an abstract depiction of a preferred
center 107, a LINAC device 105, additionally a solid state flat
panel detector 607, and an optional beam blocker 608. In the view
of FIG. 5a the patient table normally located above the
radiotherapy system as well as other components that are visible in
other Figs. have been removed from the visual field so as to more
easily illustrate features of a preferred embodiment of the
radiotherapy system.
[0037] The radiotherapy system of FIG. 5a comprises a radiation
beam centerline 601, a compact LINAC 602, a target assembly and
carousel 603, a primary dual independent collimator 604, a tertiary
multi leaf collimator 605, a monitor chamber for beam streams 606,
a solid state panel detector 607 and optionally a beam blocker 608.
Also shown in FIG. 5a is center 107 of the system, arrows 609
representing the direction of rotation of the LINAC in tandem with
detector 607 and beam blocker 608, and x-y system 501 indicating
the x-direction and y-direction of the machine in this
illustration.
[0038] FIG. 5b illustrates a side view of a preferred embodiment of
a portion of the radiotherapy and imaging device used in the system
shown in FIG. 5a. Again, for ease of illustration components of the
system that are visible in other Figs. have been omitted. As seen
in FIG. 5b, the preferred embodiment comprises a linear accelerator
(LINAC) 602, a target assembly and carousel 603, a primary
collimator 604, a tertiary collimator 605, a flat panel detector
607, and an optional beam blocker 608.
[0039] The radiation source 602 (which can but need not be a Linac
source) in this embodiment preferably operates to produce one or
more of the following four therapeutic forms of radiation: (i)
direct electron (e-) beams, (ii) direct proton (p+) beams, (iii)
high energy Bremstrahlung photons from an accelerator source, (iv)
high energy photons from a radioisotope (Cobalt-60). When high
energy photons from a Bremstrahlung source are chosen as the
therapeutic form of radiation then source 602 preferably operates
to produce a stream of therapeutic photons having a maximum
Bremstrahlung energy at or in the range 1 MeV to 10 MeV, preferably
an average energy in the 4 MeV-6 MeV range, or in the 1 MeV-4 MeV
range. In the most preferred configuration, a compact LINAC in the
radiotherapy system produces a stream of therapeutic photons for
irradiating breast tissue having an average energy in a specified
range suitable for breast-related irradiation such as within the
range of 1-2 MeV. As understood by applicants, a compact LINAC
capable of producing therapeutic photons from a Bremstrahlung
source wherein said photons have an average energy between 1-2 MeV,
uses electrons with a peak energy preferably in the range of 1-6
MeV and more preferably within the energy range 4-6 MeV.
Historically, as understood by applicants, LINAC manufacturers have
attempted to reproduce the effective energy of Cobalt 60 decay
photons (1.25 MeV) when making LINAC sources for treating breast
tissue. Cobalt-60 itself could also be used in the radiotherapy
device claimed herein and the need for an accelerator removed. When
a direct electron beam is selected as the therapeutic form of
radiation, the LINAC preferably produces a stream of electrons,
wherein the electrons have an energy range from 1-10 MeV,
preferably in the range of 4-6 MeV. When a direct beam of protons
are used as the therapeutic form of radiation, the energy range is
preferably between 1-15 MeV. Any of the forms of LINACs that are
available from manufacturers such as Varian may also be made more
compact and thus the machine size smaller by the utilization of
superconductive wave guide materials and associated technologies
such as currently being used to generate superconducting cyclotrons
for treating other deep-seated lesions such as prostate cancer.
[0040] The radiation source 602 produces a radiation beam
centerline that ideally passes from the exit of the source straight
through a center of the system, which is usually the lesion of the
breast being treated or is some line through another volume that
should be subjected to radiation therapy.
[0041] The target assembly and carousel 603 included in the
radiotherapy apparatus is used in an embodiment of the radiotherapy
apparatus to switch the type of therapeutic radiation chosen for a
particular volume in a patient's breast or surrounding tissue. In
an electron mode, the radiotherapy apparatus can emit beta rays
that are produced in a LINAC or comparable radiation source. While
in a photon mode, the radiotherapy apparatus can be configured for
the production of photons such as gamma or x-rays.
[0042] Following the target assembly and carousel is the primary
dual independent collimator 604. The primary collimator 604 is
followed by the tertiary or multi leaf collimator 605 that can
produce in a non-limiting example a 3 mm leaf width at radiation
and rotational center 107 of the system for precision treatment of
voxels located within the breast.
[0043] The radiotherapy apparatus additionally can house a monitor
chamber 606 positioned before the multi leaf collimator to assist
in determining the amount of radiation being emitted from the
radiation source and subsequently delivered to a particular volume
in a patient. Preferably, monitor chamber 606 would remain in
dynamic communication with a concurrent radiation monitoring system
so that the radiotherapy system as accurately as possible provides
therapeutic radiation in accordance with an individualized
radiotherapy patient treatment plan.
[0044] After passing through the center 107, the radiation strikes
a solid state flat panel detector 607 used for portal imaging. The
flat panel detector 607 is moveable relative to the beam of
radiation so that it can be placed in the path of the beam for
imaging and taken out of the path of the beam for radiation
treatment.
[0045] Optionally, a beam blocker 608 can be placed in the path of
the beam to effectively stop radiation that has passed through the
irradiated volume. As shown in FIGS. 5a and 5b, optional beam
blocker 608 is placed within the path of the radiation emitted from
source 602 illustrated by photon beam centerline 601 and positioned
downstream of center 107 and flat panel detector 607. The optional
beam blocker 608 can cut down the cost of shielding the room
thereby reducing the structural footprint of a room housing this
system, and making the system as a whole easier and less expensive
to install and operate in hospitals, clinics, and other such
facilities.
[0046] FIGS. 6a and 6b illustrate a variation of the system in
which patient table 101 is supported on a motorized pedestal 650
that can selectively move table 101 along some or all the x, y, and
z axes illustrated in FIGS. 6a and 6b, and also can tilt table 101
about some or all of these the axes. Another motorized pedestal 652
supports a motorized plate 654 that in turn supports an arm 656 to
which is mounted another arm 660 supporting therapy radiation
source 105, portal imaging detector 108, and blocking plate 608 and
any imaging system schematically illustrates at 658. Pedestal 652
selectively rotates plate 654 to move arm 656 and the components it
carries between the positions shown in solid and in dotted lines,
including any intermediate position. Motorized plate 654
selectively moves arm 656 and the components attached to it up and
down as illustrated by arrows in the z-direction and also
telescopes or otherwise extends arm 656 and the components it
carries in the y-direction as also illustrated by a bidirectional
arrow. Arm 656 also can be motorized to selectively rotate arm 660
about the z-axis at point 662 as illustrated by a bidirectional
curved arrow. In addition, arm 660 can be motorized to selectively
rotate radiation source 105 about the x-axis at 664 as illustrated
by another bidirectional curved arrow. These translational and
rotations motions are powered and controlled by units such as 610
and 612 (FIG. 4a) that are omitted from the illustration in FIGS.
6a and 6b for clarity. FIG. 6b illustrates the same arrangement as
FIG. 6a but in a front elevation. Typically the patient would be
prone on table 101, with a breast extending downwardly through an
opening or into a depression in table 101, so that the breast
and/or related tissue can be imaged and/or treated with radiation
from below table 101, through the motions referred to above patient
tissue can also be treated with a radiation beam that extends from
below table 101 through the patient at an angle to the horizontal,
for example as illustrated in FIG. 4b, or at any other suitable
angle to the horizontal. Alternatively, if desired the patient can
be in another position, such as the supine position, to be imaged
and/or treated with radiation from a source position above table
101, such as illustrated in dotted lines in FIGS. 6a and 6b.
[0047] FIG. 7 illustrates in side elevation an alternative that
includes, in addition to the arrangement of FIGS. 6a and 6b, an arm
700 that is at the other side of patient table 101 and is mounted
to plate 654 in a manner similar to that used for arm 656. Again,
plate 654 can be motorized to selectively move arm 700 up and down
as seen in FIG. 7 and illustrated by arrows, and to extend or
contract arm 700 in the y-direction as illustrated with a
bidirectional arrow. Arm 700 carries a specialized breast CT
scanner 712 that is otherwise similar to commercially available CT
scanners available from companies such as Giotto of Italy and
distributed in this country primarily for imaging extremities by
Hologic, Inc. of Bedford, Mass. but is smaller and lighter to serve
as a dedicated breast CT scanner. When plate 654 rotates about the
y-axis such that arm 700 is below patient table 101, a patient
breast extending downwardly from the upper surface of table 101 can
be positioned in an opening 714 of CT scanner 712 and conventional
CT scanning can be carried out to generate or adjust or verify
treatment plans for treatment that can be carried out with the
equipment mounted to arm 656. The components and motions in FIG. 7
that are in addition to those associated with arm 700, including
ones not labeled or otherwise marked in FIG. 7, can be the same as
in FIGS. 6a and 6b.
[0048] All patents and other publications and patent application
identified above are hereby incorporated by reference in this
patent specification.
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