U.S. patent application number 10/118415 was filed with the patent office on 2002-11-14 for brachytherapy systems and methods.
Invention is credited to Munro, John J. III.
Application Number | 20020169354 10/118415 |
Document ID | / |
Family ID | 26816335 |
Filed Date | 2002-11-14 |
United States Patent
Application |
20020169354 |
Kind Code |
A1 |
Munro, John J. III |
November 14, 2002 |
Brachytherapy systems and methods
Abstract
A system for brachytherapy is provided. The system includes an
implantation device having a spacer and a socket at opposing ends
of the spacer. The device further includes a seed securely
positioned within the socket. A plurality of spacers and seeds may
be joined into an assembly. The device may be deployed at an
implantation site by use of a delivery mechanism, such as needle.
The presence of the spacers minimizes movement of the seeds
subsequent to deployment, so as not to alter dose distribution for
subsequent irradiation.
Inventors: |
Munro, John J. III; (North
Andover, MA) |
Correspondence
Address: |
FOLEY HOAG LLP
PATENT GROUP, WORLD TRADE CENTER WEST
155 SEAPORT BOULEVARD
BOSTON
MA
02110-2600
US
|
Family ID: |
26816335 |
Appl. No.: |
10/118415 |
Filed: |
April 8, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60290108 |
May 10, 2001 |
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Current U.S.
Class: |
600/3 ;
600/4 |
Current CPC
Class: |
A61N 5/1027 20130101;
A61N 5/1001 20130101; A61N 2005/1011 20130101; A61N 2005/1023
20130101 |
Class at
Publication: |
600/3 ;
600/4 |
International
Class: |
A61N 005/00 |
Claims
What is claimed is:
1. An implantable device for radiation therapy comprising: a
substantially cylindrical member having opposing ends, a central
section positioned between the opposing ends, and a socket at each
of the opposing ends; and a radioactive source having a blunt end
and being partially positioned within one of the sockets, such that
the blunt end on the radioactive source is exposed.
2. A device as set forth in claim 1, wherein the central section is
integral with the sockets at each of the opposing ends of the
cylindrical member.
3. A device as set forth in claim 1, wherein the central section
includes a plug distinct from and relatively shorter than the
cylindrical member, such that difference in length between the plug
and the cylindrical member defines the socket at each of the
opposing ends of the cylindrical member.
4. A device as set forth in claim 1, wherein each of the sockets
includes an inner diameter sufficiently sized to securely retain
the radioactive source therein.
5. A device as set forth in claim 1, wherein each of the sockets
includes a depth sufficient to retain a portion of the radioactive
source, so as to minimize movement of the radioactive source after
implantation.
6. A device as set forth in claim 1, wherein the cylindrical member
is made from a flexible material.
7. A device as set forth in claim 1, wherein the cylindrical member
is made from a bioresorbable material.
8. A device as set forth in claim 7, wherein the bioresorbable
material includes a formulation which permits relatively minimal
resorption over a defined period with subsequent substantially
complete resorption thereafter.
9. A device as set forth in claim 7, wherein the bioresorbable
material includes poly-(L-lactide), poly-(DL-lactide),
polyglycolide, or a combination thereof.
10. A device as set forth in claim 1, wherein the radioactive
source is a substantially elongated segment.
11. A device as set forth in claim 10, wherein the radioactive
source includes one of iodine-125, palladium-103, cesium-137, and
iridium-192.
12. An assembly for radiation therapy comprising: a plurality of
cylindrical members, each having opposing ends, a central section
positioned between the opposing ends, and a socket at each of the
opposing ends; a radioactive source positioned between two
cylindrical members, such that the radioactive source is partially
retained within one socket of each cylindrical member, to permit
joining of the cylindrical members in series along a common
axis.
13. An assembly as set forth in claim 12, further including a
radioactive source partially positioned within a distalmost socket
of a distalmost cylindrical member in the series.
14. An assembly as set forth in claim 13, wherein the radioactive
source positioned within the distalmost socket includes an exposed
blunt end.
15. A method for manufacturing a brachytherapy implant, the method
comprising: providing a cylindrical member having opposing ends, a
central section positioned between the opposing ends, and a socket
at each of the opposing ends; placing a radioactive source within a
socket; and securing the radioactive source within the socket.
16. A method as set forth in claim 15 further comprising: placing a
second radioactive source with the opposing socket; and securing
the second radioactive source within the opposing socket.
17. A method for manufacturing a brachytherapy implant, the method
comprising: providing a tubular member having opposing ends;
placing within the member a plug having a length relatively shorter
than that of the member, such that the difference between the plug
and the tubular member defines a socket at each of the opposing
ends of the tubular member; positioning a radioactive source within
a socket; and securing the radioactive source within the
socket.
18. A method as set forth in claim 17 further comprising:
positioning a second radioactive source with the opposing socket;
and securing the second radioactive source within the opposing
socket.
19. A method as set forth in claim 17, wherein the step of placing
includes securing the plug to the tubular member.
20. A method for treating pathological tissues, the method
comprising: identifying a site having pathological tissues;
providing an implantable device comprising at least one
substantially cylindrical member having opposing ends, a central
section positioned between the opposing ends, a socket at each of
the opposing ends, and at least one radioactive source positioned
within one of the sockets; positioning the implantable device
within a lumen of delivery mechanism; inserting the delivery
mechanism at the site having the pathological tissues to a depth
which permits access to the pathological tissues; and delivering
the implantable device from the lumen of the delivery mechanism to
the site of pathological tissues.
21. A method for treating pathological tissues, the method
comprising: providing an implantable device comprising at least one
substantially cylindrical member having opposing ends, a central
section positioned between the opposing ends, a socket at each of
the opposing ends, and at least one radioactive source positioned
within one of the sockets; surgically exposing a site having
pathological tissues; positioning the implantable device within the
exposed site; and closing the exposed site to retain the
implantable device therein.
Description
RELATED U.S. APPLICATION(S)
[0001] This application claims priority to U.S. Provisional
Application Serial No. 60/290,108, filed May 10, 2001, which
application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to implantable devices, and in
particular, to implantable devices for radiation therapy.
[0003] 2. Background Art
[0004] Ionizing radiation is employed in the management of a wide
variety of malignant tumors, providing a mechanism whereby the
malignancy can be destroyed while the normal tissues are preserved.
With preservation of normal tissues, normal function and normal
appearance may also be preserved. Hence, ionizing radiation forms
part of the treatment for over half of all patients with cancer.
The overall effectiveness of radiation therapy, however, depends
upon the balance between effective tumor control and morbidity due
to the treatment. It is understood that the differential effects of
ionizing radiation on tumors and normal tissues gives rise to a
favorable therapeutic ratio for most patients. However, radiation
can have destructive immediate and delayed effects on normal
tissues. Techniques employed for radiation therapy significantly
affect the incidence and severity of these destructive effects.
[0005] Because all types of ionizing radiation affect tissues via
the same basic physical mechanisms, differences in spatial or
temporal distributions are responsible for different effects
observed with equal physical doses. The method for delivering
radiation thus becomes highly significant. Treatment modalities for
delivering therapeutic ionizing radiation include external beam
radiation and direct placement of radioactive sources within
tissues. This latter technique, termed brachytherapy, may permit
delivery of ionizing radiation to a tumor in higher doses than
those achievable with external beam radiation. Conventional
external beam radiation treatments rely on multiple fractions of
dose in order to ensure that the highest fraction of tumor cells
are exposed at the most sensitive parts of the cell life cycle.
Brachytherapy implants, such as brachytherapy seeds, on the other
hand, can supply a continuous and highly localized radiation dose
to the surrounding tissue. Because a delivered dose from a
radiation source decreases proportionately to the square of the
distance from that source, brachytherapy permits the delivery of
very high radiation doses to those areas of a tumor in close
proximity to the implant, with relative sparing of more distant
tissues. With careful placement so that the radiation source is in
proximity to the tumor and distant from normal tissue, effective
therapy against the tumor may be combined with minimal collateral
damage to normal tissues. A variety of radioisotopes, including
iodine-125, palladium-103, cesium-137, and iridium-192, may be used
in the treatment of cancers involving such tissues as the breast,
the prostate, the brain, along, the head and neck, the female
reproductive tract, the musculoskeletal system and related soft
tissues, and the eye.
[0006] As understood herein, those radioactive sources employed in
brachytherapy implants will be termed "seeds." Commonly, seeds are
intended for permanent implantation. A description of certain types
of seeds can be found in BH Heintz et al., "Comparison of I-125
sources used for permanent interstitial implants," Medical Physics,
Vol. 28, No. 4, p. 673 (April 2001), the contents of which are
hereby incorporated by reference. Certain devices known in the
prior art are intended for insertion directly into the tissues
without employing a needle or other similar delivery device. An
example of such a device may be found in the disclosure of U.S.
Pat. No. 4,815,449. This patent provides, in certain embodiments,
an implant of sufficient rigidity to be driven into a tumor without
deflection, so that the implant may be used independently of a
positioning or delivery device.
[0007] Alternatively, brachytherapy seeds may be positioned in the
tissues to be treated by insertion through a delivery device, for
instance, a needle. Using a delivery device may allow more precise
positioning of seeds in areas requiring treatment. Brachytherapy
seeds from various manufacturers may be made to the same set of
specifications so that they are compatible with those delivery
systems in common use. In those delivery systems, the seeds may be
preloaded into needles or other delivery devices. The position of a
plurality of seeds within the delivery device may be maintained by
placing loose spacers between the seeds to establish and maintain a
desired positioning. Once the seeds are positioned in the delivery
device, insertion into the tissues takes place. To insert the
seeds, the needle containing them must first be inserted to a
preselected depth into the appropriate positioned in the patient's
tissues. An injection mechanism such as a mandrel may then be
inserted into the needle with its distal end in contact with the
seeds. The needle, thereafter, may be withdrawn over the mandrel,
leaving the seeds and loose spacers resident in the preselected
tissue area. Once positioned within the tissues using this method,
the seeds and loose spacers are free to move from their original
position, as there are no constraints on the position or
orientation of the seeds. This can lead to the undesirable
consequence that dose distribution within the tissue may be
changed, for instance, movement of the seeds after deployment can
change the area being irradiated, and can change the dose being
delivered both to the preselected tumor regions and to the
surrounding normal tissues.
[0008] There remains, therefore, a need for a system which can
retain the brachytherapy seeds in position relative to one another
prior to delivery, and which can retain the position of the
brachytherapy seeds in relation to the tumor after the seeds are
delivered into the tissues.
SUMMARY OF THE INVENTION
[0009] The present invention provides, in one embodiment, an
implantable device for radiation therapy of pathological tissues.
The device, in an embodiment, includes a substantially cylindrical
member having opposing ends, a central section positioned between
the ends, and a socket at each of the opposing ends. The device
further includes a radiaoactive source partially positioned within
one of the sockets, such that the blunt end on the radioactive
source is exposed.
[0010] In another embodiment of the invention, an assembly of a
plurality of cylindrical members, each having opposing ends, a
central section positioned between the opposing end and a socket at
each of the opposing ends. The assembly further includes a
radioactive source positioned between two cylindrical members, such
that the radioactive source is partially retained within one socket
of each cylindrical member, to permit joining of the cylindrical
members in series along a common axis.
[0011] In a further embodiment, the invention provides a method for
manufacturing a brachytherapy implant. The method includes
providing a cylindrical member having opposing ends, a central
section positioned between the opposing ends, and a socket at each
of the opposing ends. Next, a radioactive source may be placed
within a socket and subsequently secured therein. A second
radioactive source may be placed in the opposing socket and
subsequently secured therein.
[0012] A method of treating pathological tissues is also provided
in accordance with an embodiment of the present invention.
Initially, a site of pathological tissues is identified. Next, an
implantable device is provided. The device, in one embodiment,
includes at least one substantially cylindrical member having
opposing ends, a central section between the opposing ends, a
socket at each of the opposing ends, and at least one radioactive
source positioned within one of the sockets. The device can
thereafter be placed within a lumen of a delivery mechanism. Once
the implantable device is placed within the lumen, the delivery
mechanism can be inserted at the site having the pathological
tissues to a depth which permits access to the pathological
tissues. Subsequently, the implantable device can be delivered from
the lumen of the delivery mechanism to the site of the pathological
tissues.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0013] FIG. 1 illustrates an implantable device in accordance with
one embodiment of the present invention.
[0014] FIGS. 2A-B illustrate a spacer for use in connection with
the device illustrated in FIG. 1.
[0015] FIGS. 3A-B illustrate another spacer embodiment for use with
the device illustrated in FIG. 1.
[0016] FIG. 4 illustrates an assembly of implantable devices in
accordance with an embodiment of the present invention.
[0017] FIGS. 5A-C illustrate a method for implanting the device, in
accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0018] FIG. 1 illustrates an implantable device 10 for radiation
therapy of pathological tissues, for example, a tumor, through the
use of a delivery device, such as a needle. As shown FIG. 1, the
device 10 includes, in accordance with one embodiment of the
present invention, a substantially cylindrical spacer 14 and
radioactive sources, such as seeds 12 and 18, positioned at
opposing ends of the spacer 14.
[0019] Looking now at FIGS. 2A-B, the spacer 14, in an embodiment,
includes a substantially solid central section 22 and opposing
sockets 24 and 26 positioned at each end of the central section 22.
The opposing sockets 24 and 26, are adapted so that each can
receive and retain a portion of a radioactive seed 12 or 18, or a
space-occupying socket filler (not shown). In this manner sockets
24 and 26 may be provided with an inner diameter D which can
securely receive a seed 12 or 18 therein. It should be noted that,
although illustrated in FIG. 2B as circular, each socket may be
provided with a diameter D and a circumferential profile of any
geometrical pattern, as radioactive seeds for brachytherapy may
come in various dimensions and configurations, so long as the seed
can be securely positioned within the socket. If desired, the
opposing sockets 24 and 26 may be provided with similar inner
diameters and/or circumferential profiles, or with different inner
diameters and/or circumferential profiles.
[0020] In accordance with one embodiment of the present invention,
the spacer 14 can include an inner diameter D of about 0.8
millimeters (mm), suitable for accommodating a brachytherapy seed,
and an outer diameter D' of about 1.0 mm, suitable for unobstructed
passage through an interior channel (i.e., lumen) of a needle
(FIGS. 5A-C) or other delivery devices employed in the implantation
of brachytherapy seeds into a patient. For example, an 18 gauge
needle, suitable for implant delivery, is understood to have an
interior channel with a diameter of about 1.05 mm, which diameter
should provide sufficient clearance for the spacer 14 to pass
therethrough. The spacer 14 can also include a central section 22
that is approximately 5.5 mm in length, and opposing sockets 24 and
26 that are each approximately 2 mm in length to provide a spacer
14 that is approximately 9.5 mm or slightly longer in length. It
should be appreciated that the inner diameter D, the outer diameter
D', the central section 22 and the sockets 24 and 26 can be
manufactured with different dimensions to accommodate the type of
treatment to be performed.
[0021] The spacer 14 of the present invention, as it is designed
for delivery and placement within tissues through a delivery
device, may be made from a flexible material. In one embodiment of
the present invention, the spacer 14 may be made from a
bioresorbable polymer, such as poly-(L-lactide), poly-(DL-lactide),
polyglycolide, or any other bioresorbable polymer known to those
skilled in the art. In certain embodiments, the polymeric
formulation may be chosen, so that the absorption thereof would be
minimal over a certain period, for example, from about 60 to about
120 days, with substantially complete absorption thereof in about a
year.
[0022] The spacer 14 may be fabricated, in accordance with an
embodiment, by injection molding or by similar processes.
Preferably, spacer 14 may be manufactured as a single piece, such
that the central member 22 and the opposing sockets 24 and 26 are
integral with one another.
[0023] In an alternative embodiment, referring now to FIGS. 3A-B,
the spacer 14 may be assembled from two different pieces, a tubular
member 32 and a solid plug 34. As illustrated therein, solid plug
34 may be inserted towards a center of a relatively longer tubular
member 32, such that the difference in length between the plug 34
and the tubular member 32 defines the sockets 36 and 38 at each of
the opposing ends of the tubular member 32.
[0024] The spacer 14, fabricated in the manner illustrated in FIGS.
3A-B, may have its components, such as the tubular member 32,
manufactured by an extrusion method, dip-casting, or other
processes familiar to those skilled in the art. In the dip-casting
method, a metal rod may be dipped into a viscous solution to coat
the surface of the rod. Subsequently, after drying, the coating on
the metallic rod can be pulled off to provide tubular member 32.
The solid plug 34 can thereafter be inserted within the tubular
member 32 and affixed therein by the use of, for instance, a
friction-fit, biocompatible cement, bioresorbable cement, or by any
other affixation method known in the art. Of course, the solid plug
34 need not be affixed within the tubular member 32 and its
position may be maintained by placement of the brachytherapy seeds
into the opposing sockets of tubular member 32.
[0025] With reference now to the radioactive seeds 12 and 18, as
shown in FIG. 1, each of seeds 12 and 18 is substantially elongated
and includes a proximal end 20 and a distal end 21. The proximal
end 20 is typically received within the sockets of device 10. The
exposed distal end 21, on the other hand, may be rounded or
blunted, so that trauma to surrounding tissues can be minimized
during and subsequent to the implantation of the device 10. In an
embodiment of the invention, both the distal end 20 and proximal
end 21 can be rounded or blunted, so that regardless of which end
is within a socket of device 10, the remaining exposed portion of
the seed 12 includes a blunt end.
[0026] The seeds for use in connection with the device 10 of the
present invention may be manufactured, in one embodiment, from a
variety of radioisotopes, including iodine-125, palladium-103,
cesium-137, and iridium-192. The seeds for use with the device 10
may also be obtained commercially, for instance, seed model 3500
manufactured by Implant Sciences Corporation of Wakefield, Mass.,
or may be any other seed model familiar to skilled artisans.
Although illustrated in FIG. 1 as two similarly dimensioned seeds
12 and 18, it should be understood that various dimensions and
configurations of the seeds may be employed in accordance with the
therapeutic demands of a particular clinical situation. Moreovere,
seeds of differing sizes may be employed for use within one
implantable device 10.
[0027] The seeds 12 and 18, in an embodiment, may be secured to the
spacer 14 by means of a friction-fit (i.e., press-fit), a
bioresorbable cement, a biocompatible cement, or by any other
affixation method known to those skilled in the art.
[0028] Referring now to FIG. 4, the device 10 may be joined with
one another to provide an assembly 40 of spacers 42 and seeds 44.
As illustrated, additional spacers 42 may be added to the assembly
40 by positioning an existing exposed distal end of the seed 44
within a socket of a new spacer 40. Depending on the situation and
the treatment required, the assembly 40 may include a seed 44 at
each end of the assembly, one seed at an end of the assembly with
the other end empty leaving an exposed socket, or no seed at either
end of the assembly. Affixation of the seeds 44 to the spacers 42
may be accomplished by employing the means provided above.
[0029] To treat pathological tissues, looking now at FIGS. 5A-C, an
assembly 50 of spacers 51 and seeds 52 may be fabricated and
positioned within a lumen 53 of a delivery device, such as a needle
54. The needle 54, subsequently, can be placed at a site selected
for implantation and inserted to a preselected depth, so as to
permit the needle to access the pathological tissues. An injection
mechanism, such as a mandrel 55, can then be inserted into the
needle 54 until its distal end contacts the assembly 50. The needle
54 may, thereafter, be withdrawn over the mandrel 55, leaving the
assembly 50 at the site of implantation. The presence of the
spacers 51 prevents the seeds 52 from substantially moving away
from the initial site of implantation, so as not to alter the dose
distribution within the tissue for subsequent irradiation.
[0030] Alternatively, the site selected for implantation can
initially be surgically exposed. Thereafter, the assembly 50 can be
placed within the exposed site. Once the assembly 50 has been
securely positioned within the site, the site may be closed by
suturing to retain the assembly 50 therein.
[0031] It should be understood that although an assembly is
discussed in connection with the treatment of pathological tissues,
an implantation device having one spacer 51 and one or two
radioactive seeds 52 may be used.
[0032] While the invention has been described in connection with
the specific embodiments thereof, it will be understood that it is
capable of further modification. Furthermore, this application is
intended to cover any variations, uses, or adaptations of the
invention, including such departures from the present disclosure as
come within known or customary practice in the art to which the
invention pertains, and as fall within the scope of the appended
claims.
* * * * *