The present invention relates to systems and methods for delivering a plurality of radioactive sources to a treatment site, and to methods of, sterilizing, transporting and customizing such radioactive sources.
In interstitial radiation therapy, one method for treating tumors is to place small, radioactive seeds in or near the tumor site. This gives a high radiation dose to the tumor while reducing the radiation exposure in the surrounding healthy tissues. Commonly known implants take the form of loose seeds and spacers that are implanted by needle in the target tissue, or the seeds may be contained within a woven or braided absorbable carrier such as braided suture material and implanted in the target tissue. The loose seeds, however, are dependent on the tissue itself to hold each individual seed in place during treatment, and are known to have a tendency to migrate as the tumor grows or shrinks. Similarly, woven or braided sutures do not assist in the placement of the seeds relative to the target tissue.
Furthermore, loose seeds require time-consuming assembly by the treating physician or a technician prior to implantation into the patient. The loose seeds are typically shipped to the treatment facility directly, where the treatment physician or a technician has to manually load the loose seeds and spacers into a needles prior to the operation. The seeds are placed in a pharmaceutical counting board, and the treating physician has to painstakingly separate and load each seed, followed by the appropriate number of spacers, then additional seeds, etc., into each implant needle. The time-consuming and arduous process needlessly prolongs the physician's exposure to radiation.
Recently, the use of integrated elongate assemblies, or “seed strands,” has grown in popularly. There are many benefits of using seed strands, both pre-implantation and post-implantation. Seed strands are easier to handle and load into needles, as they eliminate the need to manually sort each seed and spacer. The “spacers” in the seed strands are integrated into the strand itself. Unlike loose seeds which can migrate as the tumor grows or shrinks, a seed strand can maintain correct spacing between seeds even after being introduced into the body.
One such seed strand available on the market, Amersham Health Product's Rapid Strand™, is shipped prior to loading into needles. Each Rapid Strand™ is secured in individual grooved strand carriers made of plastic, and the carriers inserted into individual steel shielding cylinders. The cylinders are then individually sealed within a sterilization pouch, which is then sealed in a bag. To use these strands, a treating physician has to cut open each bag and pouch, remove the individual cylinder from within, slide out the grooved carrier, use a scalpel to cut the strand cradled inside the grooved carrier, retrieve the strand, then individually load each strand into a needle. The needles are then inserted in a shielded metal box for sorting and temporary storage prior to the implantation procedure.
The individual packaging of these strands can be cumbersome and can create a lot of potentially bio-hazardous or radioactive packaging to dispose of. The steel cylinders are bulky and heavy to transport. Further, prolonged manipulation by hand is required of the treatment physician to prepare the seed strands for implantation. This exposes him needlessly to the radiation.
What is desired is a delivery system that can hold multiple radioactive seed strands from the sterilization process, through shipping, and until pre-operation preparation, without the need to remove the strands from the carrier. This system would minimize undesirable exposure by the physician to the radiation, and at the same time reduce the amount of packaging needed to safely transport the seed strands in a sterile environment.
It is to be understood that the seed strands must be sterilized vigorously before they can be delivered to the treatment facility. Seed strands are typically sterilized with the use of Ethylene Oxide gas. After sterilization, the strands can be shipped pre-loaded into needles (in which case the needle and the strand were sterilized together), or separate from the needles.
It is, therefore, an object of the invention to provide a carrier that can be sterilized by a variety of methods, including the use of Ethylene Oxide (EtO) gas.
It is another object of the invention to provide a transportation system that is small, lightweight and easy to handle, yet has sufficient shielding for transporting a multitude of radioactive seed strands.
It is a related object to provide a transportation system that produces a smaller amount of waste to discard compared to previously known systems.
It is a further object of the invention to provide a system that allows for the shipping of seed strands without the strands being pre-loaded into needles. This allows the treating physician freedom of choice in choosing which make or style of implantation needle to use.
It is a object of the invention to provide a novel delivery system with an integrated measuring and cutting board. This allows the treating physician or a technician to easily and accurately cut strands into pieces of desired length in the operating room, and load the strand pieces into needles immediately prior to implantation, whether a pre-operative dosimeter plan was formulated or not. A related object is to have the capability to ship extra spacer material for the user to configure special loads.
Another object of the invention is to provide a transportation system that keeps the multiple radioactive strands shielded from the user, except for the one strand that the user is currently working on.
It is a further object to provide a carrier that could securely hold a multitude of seed strands.
A related object is to provide a system that can transport one patient's entire requirement of radioactive seed strands in one discrete package.
The above and related objects are addressed by embodiments of the instant invention. Accordingly, an integrated sterilization and transportation system for radioactive seed implants is provided for the shipping of multiple strands without needles. The system is comprised of an outside lead shield envelope, a “fluted” plastic carrier for the individual strands, and an integrated pull-out measuring and cutting board. In the following discussion, it is to be understood that the invention is applicable for both custom-made and generic seed strands, and are not limited to the embodiments disclosed in the inventors' prior patents or any pending applications incorporated herein by reference.
a-2c depict in sequence perspective views the measuring and cutting board, and plastic carrier being inserted inside the shielded envelope of the system of the invention of
a-3d depict in sequence perspective views the pull-out tab being rolled up and folded inside the shielded envelope of
a-5c show in sequence perspective views the shielded envelope of
a-6b show in cross-sectional view the layered construction of the movable assembly of the system in
a-7g show in side cross-sectional view the system of
a-8c show in side cross-sectional view another embodiment of the movable assembly of the system in
In accordance with an embodiment of the invention, the sterilization and transportation system 100 shown in
Iodine-125 seeds 16 are commonly used for seed strands. The half value thickness of lead for Iodine-125 is 0.025 mm. Thus, a 0.25 mm lead sheet will provide greater than 99% reduction in exposure. In the preferred embodiments of the invention, the shielded envelope 10 of the system 100 should have a lead lining on the inside that is at least 0.25 mm thick, and up to 0.40 mm thick. This would provide shielding that is above required safety standards, while still keeping the shielded envelope 10 relatively lightweight.
After the strands are loaded into the plastic carrier 11, the measuring and cutting board 12 and plastic carrier 11 are slid inside the lead shielded envelope 10.
a shows the same configuration as
In the preferred embodiment, the pouch 30 is made of a paper type product such as Dupont® Tyvek®, which is chosen for its bacteria growth resistance, tear strength, and puncture resistance, as well as compatibility with existing and emerging sterilization methods. The pouch 30 is sealed and the pouch is loaded into a sterilization chamber for sterilization. The pouch 30 will remain sealed from this point on, until the end-user opens it. In the preferred embodiment, EtO gas sterilization is used, but other methods may also be possible for use with the system 100 as long as a vigorous sterility verification system is in place.
The lead shielded envelope 10 remains open inside the sealed paper pouch 30 during the sterilization process, so that the sterilizing agent can access the system 100, including the plastic carrier 11 and the measuring board 12, the seed strands 13, strands of spacer material 14 and the radioactive seeds 16. After the system 100 and its contents have been thoroughly sterilized, the pouch 30 is removed from the sterilization chamber. The mouth 10a of the shielded envelope 10 is lined with an adhesive, and pressing down on the mouth 10a through the sealed paper pouch 30 closes the shielded envelope 10 by forming a seal 10b. The seed strands 13 are now secured inside the system 100, and the system 100 ready to be loaded into a container for shipping.
Referring to
At the treatment center the pouch 30 is removed from the box and brought into a sterile preparation area for preparing and customizing the seed strands 13 for implantation. The lead shielded envelope 10 remains sealed at this point. The pouch 30 is opened and the system 100 removed. Refer to the sequence depicted in
a to 6b show in detail the layered construction of the system 100. As shown in
In operation, pulling on tab 12a pulls the cutting board 12 out of the envelope 10 until the stops 12c come into contact with the “T”-shaped plank 11b. At that point further pulling on the tab 12a cause the fluted plastic carrier 11 and the seed strands 13 to be pulled out of the shielded envelope 10.
Refer now to
a to 8c show in cross-sectional view a different embodiment of the assembly of system 100, which is operated in the same way as the embodiment described immediately above. This assembly 80, as shown in
It is to be understood that seed strands manufactured using a variety of techniques can be used with the embodiments of the present invention. In addition to these seed strands referenced to and described above, the following seed strands are appropriate for use with the embodiments of the present invention.
It is desirable for Brachytherarpy seed strands to be flexible and pliable enough to move with the treatment tissue as the tissue shrinks back to pre-operative size. A seed strand also should have sufficiently axial rigidity to allow easy expulsion of the strand from the implantation needle, whereas loose seeds have been known to jam inside an implantation needle.
U.S. patent application Ser. Nos. 10/162,548 and 10/132,930 by the instant inventors disclose two such seed strands, and are incorporated herein by reference.
Patent application Ser. No. 10/132,930, filed Apr. 26, 2002, disclose a seed strand composed of a plurality of tubular shaped, hollow radioactive seeds with a bore. The seed strand is assembled with a polymeric material in the bore between the spaced seeds. In one embodiment, the polymeric material is heated in order to capture the radioactive seed elements at the desired spaced intervals. The strand is axially stiff and radially flexible, and is able to maintain the correct spacing between the seeds as the treated tumor shrinks. The polymeric material is bio-absorbable in living tissue, and is designed to be absorbed by the body in about the same the radioactive seeds become inert.
Patent application Ser. No. 10/162,548, filed Jun. 4, 2002, discloses a seed strand in which a plurality of radioactive seeds can be dispersed in a predetermined array within the strand. In one embodiment, the radioactive seeds are dispersed within pre-fabricated half-shells made of bio-absorbable material, and the half-shells fused to make the seed strand. A system for manufacturing the seed strands is also provided.
Seed strands can be custom-manufactured for each patient from the patient's preoperative dosimeter plan. This allows highly accurate placement of the seeds inside the treatment tissue, in order to provide a precise interstitial radiation dose. Strands are also available in generic, pre-fabricated form. These pre-fabricated implants typically contain seeds spaced at set increments (e.g. 1 cm), and are usually 10 cm long. While generic strands may not offer as precise a placement of seeds for the individual patient, they offer many of the same benefits over loose seeds. Since the seeds are already spaced apart in the strand, all a physician have to do is to cut a strand to the desired length and load it into the implantation needle, without having to manually count and load seeds and spacers. Further, generic strands are more economical than custom-manufactured strands, and using generic stands can also reduce the waiting time for custom-made strands.
It will be appreciated that the instant specification, drawings and claims set forth by way of illustration and not limitation, and that various modification and changes may be made without departing from the spirit and scope of the present invention. Additional aspects, objects and advantages of the invention can be obtained through a review of the appendant claims and figures. It is to be understood that other embodiments can be fabricated and come within the spirit and scope of the claims and the invention.
The following applications are cross-referenced and incorporated herein by reference as if fully set forth herein: U.S. Patent Application No. 60/360,237, entitled “System for Manufacturing Interstitial Radiation Therapy Seed Strands”, by Terwilliger et al., filed Feb. 26, 2002. U.S. Patent Application No. 60/360,272 entitled “Delivery System and Method for Interstitial Radiation Therapy Using Strands Constructed with Extruded Strand Housing”, by Terwilliger et al., filed Feb. 26, 2002. U.S. Patent Application No. 60/360,241 entitled “Delivery System and Method for Interstitial Radiation Therapy Using Seed Strands Constructed with Preformed Strand Housing”, by Terwilliger et al., filed Feb. 26, 2002. U.S. patent application Ser. No. 10/132,930 entitled “Improved Delivery System and Method for Interstitial Radiotherapy Using Hollow Seeds”, by Terwilliger et al., filed Apr. 26, 2003. U.S. patent application Ser. No. 10/162,548 entitled “Delivery System and Method for Interstitial Radiation Therapy Using Seed Strands Constructed with Preformed Strand Housing”, by Terwilliger et al., filed Jun. 4, 2002. U.S. patent application Ser. No. 10/162,546 entitled, “System for Manufacturing Interstitial Radiation Therapy Seen Strands” by Terwilliger et al., filed Jun. 4, 2002. U.S. patent application Ser. No. 10/162,006 entitled, “Delivery System and Method for Interstitial Radiation Therapy Using Strands Constructed with Extruded Strand Housings”, by Terwilliger et al, filed Jun. 4, 2002.