Surgery – Radioactive substance applied to body for therapy – Radioactive substance placed within body
Reexamination Certificate
2001-01-24
2003-06-10
Winakur, Eric F. (Department: 3736)
Surgery
Radioactive substance applied to body for therapy
Radioactive substance placed within body
Reexamination Certificate
active
06575888
ABSTRACT:
This application is related to U.S. patent application Ser. No. 09/361,553, entitled “Absorbable Brachytherapy and Chemotherapy Delivery Devices and Methods,” to William G. Mavity, Robert A. Stern, Shigemasa Osaki and Paul O. Zamora, filed on Jul. 27, 1999, and the specification thereof is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention (Technical Field)
This invention relates to methods, devices and systems for radiation delivery devices and combination radiation and drug delivery devices, and particularly methods, devices and systems for absorbable radiation delivery devices and combination radiation and drug delivery devices having elements that will be absorbed in tissue over time.
2. Background Art
Note that the following discussion refers to a number of publications by authors and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
A number of techniques have been utilized or proposed to treat tumor growth, including radiation therapy, chemotherapy, and other treatment modalities. Brachytherapy, a form of radiation therapy, relies on implanting a radiation source in the body to provide localized treatment, as contrasted, for example, with treating a site from a distance by external beam radiation. In prostate brachytherapy, radiation is delivered by small “seeds” placed within the area being treated. Such placement minimizes the risk of affecting nearby tissue, while still delivering adequate radiation to destroy diseased cells.
In general, radioactive materials such as palladium-103 (Pd-103) and iodine-125 (I-125) are used, which have a relatively short half-life and emit low energy X-rays. A variety of different types of brachytherapy devices have been used to treat cancer and various types of tumors in human or animal bodies. Art conventional brachytherapy devices are contained in small metal capsules, generally made of titanium or stainless steel, and are welded or use adhesives to seal in the radioactive material.
The art conventional brachytherapy devices generally cannot be removed after placement. Thus they remain in the body even after the effective radiation dose has been delivered. The presence of these metallic brachytherapy devices can interfere with subsequent diagnostic X-rays or other imaging modalities, since they are radiopaque. In addition, these brachytherapy devices can interfere with other treatment modalities, such as thermal ablation or external beam radiation. Further, metallic brachytherapy devices are generally of a different density than that of the tissue in which they are placed, and can migrate after placement, both while still effectively emitting therapeutic radiation or after the radioactive source has decayed. Thus the devices may enter the lymphatic system or otherwise move to a position within the body that may cause medical complications, potential diagnostic confusion and the like.
One type of conventional brachytherapy device
1
is shown in
FIG. 1
, in which the device
1
contains a therapeutic amount of a radioisotope
2
disposed in a carrier
3
. The radioisotope-containing carrier
3
is in a cavity
5
of a cylindrical casing
4
. Casing
4
, made of a metal such as stainless steel or titanium, is sealed at ends
6
and
7
, typically by welding.
Another type of conventional brachytherapy device
10
, disclosed in U.S. Pat. No. 4,891,165, is shown in FIG.
2
and employs two metal sleeves
12
and
14
. Each of the sleeves has one closed end
16
and
18
, with sleeve
14
having an outer diameter that is smaller than the inner diameter of the sleeve
12
, permitting the sleeve
14
to slide inside sleeve
12
. A radioactive source, such as pellets, can be placed inside the smaller sleeve
14
, and then the larger external sleeve
12
slid over the smaller sleeve
14
. The brachytherapy device
10
is permanently sealed, such as by welding.
Another conventional brachytherapy device
30
, disclosed in U.S. Pat. No. 4,784,116, is shown in FIG.
3
and uses a single metal tube
32
which has metal end caps
34
and
36
inserted at the ends
38
and
40
. The tube
30
contains the radioactive source. The ends
38
and
40
are welded, or adhesively secured, to the end caps
34
and
36
to seal the brachytherapy device
30
.
Yet another conventional brachytherapy device
50
, disclosed in U.S. Pat. No. 5,683,345, is shown in
FIG. 4
, has metal end plugs
52
and
54
that are slid into the open ends of a metal tube
56
. The end plugs
52
and
54
are adhesively fixed and the metal of tube
56
then bent around the end plugs
52
and
54
, or the end plugs
52
and
54
are welded to the tube
56
.
Another conventional brachytherapy device
70
is shown in
FIG. 5
, which employs a metal tube
72
with ends
74
and
76
. One end
74
of the tube
72
is welded, forming a metal weld bead
78
sealing the end
74
. After placement of the radioactive material, the end
76
is welded forming metal bead
80
closing off end
76
.
Yet another metal brachytherapy device
90
, disclosed in U.S. Pat. No. 6,132,359, is shown in
FIG. 6
, which depicts metal case
94
with a center portion
96
and two end portions
98
, and containing a radioactive source
92
. Device
90
may be made by swaging one end portion
98
of casing
94
, then welding swaged end portion
98
to provide a weld seal
100
. After placement of the radioactive source
92
within the case
94
, the second end portion
98
of casing
94
is then swaged and welded to provide a weld seal
102
. While this configuration is purported to provide a more uniform radiation dose, it still utilizes a permanently-placed metal device.
Each of the foregoing devices is expensive and difficult to manufacture, involving a very precise welding step on a highly radioactive component, requiring shielding, robotics and other complex steps. In addition, quality control on such radioactive metal sources is difficult and time consuming.
The preparation of biodegradable radioactive materials is described in U.S. Pat. Nos. 5,256,765 and 5,194,581. In these materials, a radioisotope may be bound to a biodegradable polymeric matrix where the purpose is usually to provide for controlled release of the radioactive material over time. Such biodegradable radioactive materials are generally not useful for brachytherapy since they release the radioactive material rather than localize it at the desired treatment site.
In another approach, disclosed in co-pending and co-owned application Ser. No. 09/361,553, a radiation delivery component and a drug delivery component immobilized on a bioabsorbable structure is disclosed. The bioabsorbable structure has a predefined persistence period, such that it will remain sufficiently intact after implantation at a target site in patient tissue so that it can localize or sequester the radionuclide at the target site for a minimum threshold time, and further release or disperse the drug, which may be a chemotherapeutic agent, over a complimentary time. The minimum threshold time will usually depend at least in part on the half-life of the radionuclide. In particular, the predetermined persistence period of the bioabsorbable structure will usually be substantially longer than the half-life of the radionuclide, usually being at least two times longer, preferably being at least four times longer, and often being at least ten times longer. In this way, the radionuclide is not released from the bioabsorbable structure until after the persistence period has passed, so that the maximum effect of the radiation is limited to the target, and potential systemic or clearance organ dosage to the patient is below a known or predicted level of safety.
The use of biodegradable or bioerodible materials to provide sustained or controlled rele
Stern Robert A.
Zamora Paul O.
BioSurface Engineering Technologies, Inc.
Peacock Myers & Adams
Slusher Stephen A.
Veniaminov Nikita R
Winakur Eric F.
LandOfFree
Bioabsorbable brachytherapy device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bioabsorbable brachytherapy device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bioabsorbable brachytherapy device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3128849