Products and methods of manufacturing for brachytherapy

Products and manufacturing procedures for brachytherapy

Field of the Invention

The present invention relates generally to radiotherapy. More specifically, it refers to radioactive sources for use in brachytherapy and to the procedures for the preparation of such sources.

Background of the invention

Brachytherapy is a general term that covers medical treatment that involves the placement of a radioactive source near a diseased tissue and may include the temporary or permanent implantation or insertion of a radioactive source into a patient's body. The radioactive source is, therefore, in the vicinity of the area of ​​the body being treated. This has the advantage that a high dose of radiation can be delivered to the treatment area with relatively low doses of radiation to the surrounding or intervening healthy tissue.

Brachytherapy has been proposed for use in the treatment of a variety of conditions, including arthritis and cancer, for example breast, brain, liver and ovarian cancer and especially prostate cancer in men (See, for example, the documents of JC Blasko et al., Urological Clinics of North America, 23, 633-650 (1996), and H. Ragde et al., Cancer, 80, 442-453 (1997)). Prostate cancer is the most common form of malignancy in men in the US, with more than 44,000 deaths in 1995 alone. Treatment may include temporary implantation of a radioactive source for a calculated period, followed by withdrawal. . Alternatively, the radioactive source can be permanently implanted in the patient and allowed to decay to an inert state in a predictable time. The use of temporary or permanent implantation depends on the isotope selected and the duration and intensity of the treatment required.

Permanent implants for the treatment of the prostate comprise relatively short half-life (half-life) radioisotopes and lower energies in relation to temporal sources.

Examples of permanently implantable sources include iodine-125 or palladium-103 as radioisotopes. The radioisotope is generally encapsulated in a shell, such as titanium, to form a "seed" which is then implanted. Temporary implants for the treatment of prostate cancer may involve iridium-192 as a radioisotope.

Conventional radioactive sources for use in brachytherapy include so-called seeds, which are sealed containers, for example, of titanium, which contain the radioisotope in a sealed chamber, but allow radiation to escape through the walls of the container / chamber. (see documents US 4,323,055 and US 3,351,049). Such seeds are only suitable for use with radioisotopes that emit radiation that can penetrate the walls of the chamber / container. Therefore, such seeds are generally used with radioisotopes that emit radiation and or low-energy X-rays, rather than emission radioisotopes .

Radioactive seeds are generally loaded into needles, the needles being then inserted into the treatment site, such as the prostate, using ultrasound images to guide the insertion process. The radioactive seeds are placed independently inside the needles and therefore, will be located independently within the treatment area after they have been removed from the needle, or are connected in a rope arrangement when loaded inside of a bioabsorbable, hollow suture member.

US 5,460,592 discloses a method and apparatus for transporting a radioactive device. The device comprises an elongated, flexible woven or braided bioabsorbable carrier material that has separate radioactive seeds arranged therein. When heated, the carrier material that holds the seeds becomes semi-rigid. A section of the semi-rigid carrier material with radioactive seeds disposed therein can be loaded into a conventional hollow metal dispensing needle, or applicator cartridge that is used to implant the radioactive seeds into or adjacent to the treatment site, for example a tumor .

A commercial product consisting of iodine seeds - 125 regularly separated between 0.6 cm and 1.2 cm from center to center within a braided semi-rigid bioabsorbable suture material, is available from Medi-Physics Inc. under the trade name I-125 RAPID Strand ™. This product can be used to treat conditions such as head and neck cancers, including those of the mouth, lips and tongue, brain tumors, lung tumors, cervical tumors, vaginal tumors and prostate cancer.

One of the advantages of this type of radioactive seed / suture combination is that radioactive seeds are implanted or inserted into a patient with a predetermined separation, depending on their separation in the suture material. The bioabsorbable material is then slowly absorbed into the patient's body to leave the seeds separated in position. This predetermined separation and the semi-rigid nature of the suture help a doctor calculate the total radiation dose and dose profile that will be supplied by the seeds inside the patient's body, and also helps the precise placement of the seeds. . In addition, each time more than one seed is implanted, so the time needed for implantation is reduced compared to the necessary

for the placement of individual loose seeds. The risk of seed migration separating from the implantation site is also reduced (Tapen et al., Int. J. Radiation Oncology Biol. Physic., Vol. 42 (5), pages 1063 1067, 1998).

Another advantage of the approach of the combination of the hollow suture with respect to that of the independent seeds is that the independent seeds, once they are in the treatment site, for example the prostate, could migrate leaving the prostate to other different locations. in the body, including the lungs. Migrated seeds can reduce implant quality and also potentially harm the patient.

However, this combination of hollow suture has limitations in the strength of the long axis, due to the empty areas, introduced in the arrangement during manufacturing, which are used to produce the separation between the radioactive seeds. This resistance of the long axis in the empty area is limited to the resistance of the suture material. Although the resistance of the empty area is increased during the manufacturing process with heat stiffening, the resulting resistance is still not ideal. Due to this limitation, the suture combination can sometimes get stuck inside the insertion needle, which causes the suture combination to collapse in the empty area between the radioactive seeds. This condition requires the removal of the prostate needle and subsequent reloading of the needle with independent radioactive seeds. This alteration of the technique is time consuming and expensive in nature.

An approach to remedy the situation is disclosed in US 6,264,600. It discloses a procedure and an apparatus that includes a hollow suture with an alternating plurality of radioactive seeds and intermediate separators. Although this suture / seed combination offers greater resistance to the long axis, there are several areas that can be improved.

First of all, there is still a need for even more long shaft resistance to reduce the chances of suture jam inside the insertion needle.

In addition, the combination of hollow suture / seeds and the current combination of hollow suture / seed / separator is unique in color, only with dimensional differences between the seeds and empty areas of the set. This limitation may cause uncertainty in the preparation of the implant combination. The current device only allows cutting in the empty areas of the suture combination away from the critical components of radioactive seeds. However, this is impossible once the suture combination is removed from the device.

Finally, the current suture / seed / separator combination has similar diameters of the seeds and the separators. This lack of dimensional difference makes cutting more difficult.

Therefore, there is a need for an improved radioactive source that does not suffer all the disadvantages of known sources, and which, preferably, can be produced by an automated manufacturing process.

Summary of the invention

According to the invention, therefore, a radioactive member is provided for use in brachytherapy, comprising a hollow elongated bioabsorbable suture member with a plurality of radioactive seeds and separating members arranged alternately therein, in which the members Separators are dyed a different color than the unstained radioactive seeds and are of a different diameter than the radioactive seeds. The radioactive seeds and the separating members are preferably retained therein by deformation of the suture member during heating, followed by subsequent cooling.

In one embodiment of the invention, a radioactive member is provided for use in brachytherapy comprising a hollow elongated bioabsorbable suture member with one or more grooves therein, in which one or more radioactive seeds and spacer members are alternately arranged. in a separation relationship, in which the separating members are dyed a different color than the unstained radioactive seeds and have a different diameter than the radioactive seeds. Preferably, the suture member is essentially rigid. The grooves may comprise a continuous groove or a series of discrete apertures longitudinally spaced along the suture material. Preferably, the radioactive seeds and separators are safely retained in the suture member by heat sealing.

As a further feature of the invention, there is provided a process for the production of a radioactive member for use in brachytherapy, which comprises an elongated bioabsorbable suture member with radioactive seeds and separating members arranged alternately therein, said process comprising the stages of:

a) provide a hollow bioabsorbable suture member,

b) provide a plurality of radioactive seeds,

c) providing a plurality of bioabsorbable separator members, in which the separator members are dyed a different color than the unstained radioactive seeds and have a different diameter than the radioactive seeds,

d) heating the radioactive seeds to a temperature above the melting or softening temperature of the suture material,

e) placing the heated seeds and spacer members alternately on the suture member in a predetermined pattern, whereby the suture member melts or deforms around each source and each spacer member and

f) cooling the suture member in such a way that it solidifies or hardens around each source and each separator member in order to safely hold each source in place.

In an alternative embodiment of the process, in steps d) and e), the same suture member may be at an elevated temperature (at which it does not lose its integrity), for example after extrusion, and the radioactive seeds and members Separators are then placed in the suture member such that they are held in place while cooling. In this procedure, the radioactive seeds may be cold or they may also be heated.

In step e), an external force can also be optionally applied to deform or further deform the suture member around the radioactive seeds and separator members. For example, heated plates may be applied to the outside of the suture member to further melt the suture member around the radioactive seeds and the separator members to hold them in place.

In yet another embodiment of the process, it further comprises a step of sterilization of the radioactive members.

Also disclosed, but without being part of the present invention, there is a method that uses the radioactive member for brachytherapy, said procedure comprising:

a) cut the radioactive member into one of the separator members with a prescribed length in accordance with the prescribed implantation plan;

b) inserting the cut radioactive member into one end of the connection hub of a hollow insertion needle by making a suitable insertion in a prescribed treatment area, so that the entire radioactive member is inside the needle;

c) pushing the radioactive member through the hollow insertion needle with a needle stylet, until the forward tip of the radioactive member reaches a means of plugging the needle;

d) insert the loaded insertion needle into the area of ​​treatment prescribed to a patient;

e) remove the insertion needle from around the radioactive member, leaving the radioactive member in the treatment area prescribed for the patient.

Also disclosed, but without being part of the present invention, there is another method of using the radioactive member for brachytherapy, said procedure comprising:

a) inserting an insertion needle into a treatment area prescribed to a patient;

b) cut the radioactive member into one of the separator members with a prescribed length in accordance with the prescribed implantation plan;

c) loading the radioactive member into a post-loading device;

d) transfer the radioactive member in the post-loading device to the insertion needle into which it is attached within the connection hub of the insertion needle;

e) apply a stylet to advance the radioactive member through the device after loading on the insertion needle, and finally on the patient;

f) remove the insertion needle and the device gives subsequent loading.

Brief description of the drawings

Figure 1 is a cross-sectional view of the improved suture combination of the present invention.

Figure 2 shows a partial exploded view of the elongated seed suture member and the radioactive seeds located in the first and second recesses of a fixing member with knife-edge grooves that cross the first and second recesses.

Figure 3 shows a segment of the prepared radioactive member that is loaded into a brachytherapy needle before implantation in a patient.

Figure 4 shows a segment of the prepared device that is being loaded in a post-loading device and then in a brachytherapy needle at the time of implantation in a patient.

Detailed description of the invention

Referring to the drawings, Figure 1 shows a cross section of an embodiment of the invention: a radioactive member for use in brachytherapy comprises a hollow elongated bioabsorbable suture member 3 with radioactive seeds 2 and spacer members 1 arranged alternately in the same.

Radioactive seeds 2 typically have a diameter of 0.5 mm to 1 mm and a length of 4 mm to 5 mm. However, the dimensions of radioactive seeds may vary. The separating members can be of fixed or variable length between each radioactive seed. The separator members are located on both the leading and trailing edges of the radioactive members.

The coloring of the separator members can be used to create a color scheme to easily identify the components within the suture members. The separating members 1 may be dyed, for example, violet, to distinguish them from the unstained suture members 3. The diameter size of the separator members 1, as compared to the diameter size of the radioactive seeds 2, may be different, such as smaller, to easily identify the components within the suture members 3. Heat stiffening of the radioactive member during the manufacturing process increases the stiffness of the long axis, adheres the suture member 3 to the internal radioactive seeds 2 and the separator members 1, and allows the coloration to be transferred from the separator members 1 to Suture member 3 to facilitate the identification of the components.

The suture member and the spacer member may be made of the same material. They can be of any non-toxic, biocompatible, bioabsorbable material or a mixture of such materials. As used herein, a bioabsorbable material is any material from which a substantial portion will be metabolized in a patient's body and, finally, will be removed from it. Suitable bioabsorbable materials include polyglycolic acid (PGA) and polylactic acid (PLA), polyester amides of glycolic and lactic acids, such as polymers and copolymers of glycolate and lactate, polydioxanone and the like. Such materials are disclosed in more detail in US 5,460,592. Suitable commercially available polymers include polyglypron 25 (MONCRYL ™), polyglactin 910 (VICRYL ™) and polydioanone (PDS II), all of which are available from Ethicon, Inc., of New Jersey, USA.

Other suitable bioabsorbable polymer polymers and compositions that can be used in this invention are disclosed in the following US patents: US 4,052,988, which discloses compositions that are suitable for use as absorbable sutures; US 3,297,033, which discloses the use of compositions comprising polyglycolide homopolymers as absorbable sutures; US 2,668,162, which discloses compositions comprising high molecular weight polymers of glycolide with lactide; US 2,703,316, which discloses compositions comprising lactide polymers and copolymers of lactide with glidolide; US 2,758,987, which discloses compositions comprising optically active homopolymers of L (-) lactide, ie, poly L-lactide; US 3,636,956, which discloses compositions of copolymers of L (-) lactide and glycolide which have utility as absorbable sutures; US 4,141,087, which discloses synthetic absorbable crystalline isomorphic copolyloxylate polymers derived from mixtures of cyclic and linear diols; US 4,441,496, which discloses copolymers of p-dioxanone and 2.5 morpholinediones; US 4,452,973, which discloses ABA three-block copolymers of polyglycolic acid / polyoxyalkylene); US 4,510,295, which discloses polyesters of substituted benzoic acid, dihydric alcohols, and glycolic and / or lactide; US 4,612,923, which discloses surgical devices made from absorbable synthetic polymers containing an absorbable glass filler; US 4,646,741, which discloses a surgical fastener comprising a mixture of copolymers of lactide, glycolide, and poly-p-dioxanone; US 4,741,337, which discloses a surgical fastener made of a glycolide-rich polymer blend; US 4,916,209, which discloses bioabsorbable semicrystalline polypeptide polymers; US 5,264,540, which discloses bioabsorbable aromatic polyanhydride polymers and US 4,689,424, which discloses radiation sterilizable absorbable polymers of dihydric alcohols.

Bioabsorbable polymers and polymer compositions are especially useful when they comprise bioabsorbable fillers, such as those disclosed in US 4,473,670, which discloses a composition of a bioabsorbable polymer and a filler comprising a poly-succinimide; and US 5,521,280, which discloses bioabsorbable polymers and a filler of finely divided sodium chloride or potassium chloride. Such fillers can provide greater rigidity to bioabsorbable polymers and polymer compositions.

Polyglycolic acid has a melting point of 230 ° C to 260 ° C and a glass transition point of 45 ° C to 50 ° C (Material Safety Data Sheet, Lactide / Glycolide Polymers Medisorb). If this is used as material of

Suture, then, in steps d) and e) of the methods of the invention, the sources, the separator member and / or the suture member should be heated at least to this glass transition point temperature.

The bioabsorbable material should preferably maintain its integrity once implanted for approximately 1 to 14 days. This helps to ensure that source separation is maintained for at least a short period of time after implantation. The use of the radioactive members of the invention also helps ensure adequate dosimetry and minimizes movement or separation of the source. Preferably, the suture member should be fully absorbed by living tissue in a total of approximately 70 to 120 days.

By "essentially rigid" is meant that the suture member and the spacer member must have some structural integrity and be sufficiently rigid for the proposed uses. The suture member and the spacer member must be rigid enough to maintain separation between the radioactive seeds during storage, shipping and implantation of the radioactive member. If the suture member and the separator member have melted and deformed when they are heated by the seeds in order to trap the radioactive seeds in place, then they must be stiffened again when they are cooled.

In addition, the suture member must be able to conform in an elongated shape. Preferably, once elongated, the suture member and the spacer member should be easy to cut using, for example, a scalpel or the like. Preferably, the diameter of the spacer members is different from that of the radioactive seeds, so that the spacer member can be easily identified inside the suture material. For example, the diameter of the separating members may be 0.1 mm to 0.5 mm smaller than that of the radioactive seeds. The coloring on the separator members, such as violet, can be used to create a color scheme to easily identify the components inside the suture member. Dyed separator members can be easily distinguished from unstained suture members. The suture member should also have a considerable shelf life without the need for special storage or handling conditions. The suture member must also be sterilizable by any conventional sterilization procedure, such as, for example, the use of steam, dry heat, ethylene oxide, electron beam or gamma radiation, as well as the pulsed light sterilization procedure. The preferred sterilization process is ethylene oxide.

The suture member must have a sufficient inner diameter to accommodate the radioactive seeds and the separator members. It can be of any suitable cross-section, for example, substantially circular, substantially circular with at least one flattened surface, or substantially polygonal, for example, square

or triangular A preferred suture according to the invention has a substantially square cross-section, both for ease of fabrication and to limit the surface area of ​​the suture that will be in contact with the inside of the dispensing needle, as well as to make jamming of the suture inside the needle due to friction between the needle and the suture surface. Reduced friction could also be achieved with any cross section that had at least one flat surface, for example, a substantially flattened circular section in a region in the circumference to obtain a flat surface. Suitable sutures are substantially polygonal in shape, for example, hexagonal, octagonal, or 12 or 16 faces, etc. Therefore, another preferred suture according to the invention is substantially octagonal. A substantially triangular cross section is also preferred, as it offers a less than a substantially square cross section for contact with the inner walls of a delivery needle device.

The length of the suture members may vary. Preferably, a radioactive member contains 2 to 15 radioactive seeds.

The contact surface between the inner surface of a needle or other delivery device and a suture of any cross-sectional shape can be further reduced by the provision of suitable surface structures on the surface of the suture that comes into contact with the delivery device For example, in the case of a curved suture surface, the surface contact can be reduced by incorporating ridges, spheres or other protrusions in the surface area of ​​the suture that comes into contact with the surface of The needle or delivery device. Preferably, these surface structures comprise biocompatible or biodegradable suture material. A suitable procedure for the formation of such surface structures comprises the application of a mold or a heated pressing plate, the surface of which is configured as a negative of the structures that is applied to the suture. With the application of the heated mold to the surface of the suture, the suture will flow into the cavities in the negative mold. The extraction of the mold suture and the cooling of the suture will impart a positive and reciprocal image to the surface of the suture with respect to the negative image of the mold. The protrusions and cavities produced on the surface of the suture provide a reduced contact area and less friction between the suture and a needle that is used as a delivery device.

Preferably, the suture will be visible using ultrasound imaging techniques. For example, it may comprise sound reflecting particles or gas bubbles that serve to improve its visibility by ultrasound. If the suture is a polymer, gas bubbles can be trapped in the polymer during the extrusion process to form a suture, for example, blowing bubbles in the polymer when it is being extruded. Alternatively, the polymer can be stirred (for example, by sonication) before extrusion in a gas atmosphere.

suitable, so that gas bubbles are incorporated therein. Suitable gases include air, nitrogen, carbon dioxide, Freons ™ and fluorocarbons such as perfluorbutane

Alternatively, the suture member may be subjected to a gas at a pressure, for example, greater than the atmospheric pressure, immediately before extrusion, so that the gas dissolves in the material. With extrusion combined with a reduction in gas pressure due to heating (such as extrusion at ambient pressure and at room temperature), the gas will expand to form bubbles in the suture member. Preferably, the bubbles are at or near the surface of the suture member.

Suture can be uniformly visible or not uniformly visible, by ultrasound. For example, some regions of the suture may be more visible with ultrasound than other regions. This can occur as a consequence of the presence of regions in which there are groups of gas bubbles or sound reflecting particles that are resident in a suture.

Suture can comprise, in addition or alternatively, particles that serve to improve its visibility to ultrasound. Suitable particles include metal particles (eg titanium or aluminum), glass, silica, iron oxide, sand, clay, plastics such as TEFLON ™, porous particles of uniform size not added as disclosed in US 5,741. 522 and US 5,776,496, hollow microcapsules or solid microspheres such as those disclosed in US 5,648,095, and microspheres of a molten sugar, a molten amino acid or PEG (polyethylene glycol).

One of the advantages of using, for example, radioactive members of the invention visible by image treatment, visible to ultrasound in brachytherapy, is that the signal and the image can be read, measured and analyzed by suitable computer programs with sufficient speed to allow a doctor to plan a dosimetry in real time. This is advantageous from a clinical point of view, both for the patient and for the medical staff. However, the members of the invention can be used in processes that include any type of dosimetry assignment that uses the information obtained by the visibility of radioactive seed images.

In addition, a doctor can use the same imaging technique, for example, ultrasound, when he is performing surgery to confirm the position and size of the organ (for example, the prostate), and the placement of the radioactive seeds. This could allow a doctor to calculate whether additional radioactive seeds need to be inserted, for example, in situations where the dose pattern should be recalculated based on the actual implanted position of the sources.

The total dimensions of the suture member should be such that it fits into a dispensing needle or applicator cartridge. For example, if the internal diameter of a thin-walled 18 gauge needle is 0.102 cm (0.040 inches), then the maximum effective diameter of the suture is preferably less than 0.102 cm (0.040 inches), so that it can be dispensed from such needles

The suture may be distributed uniformly or not uniformly in cross section around the sources. For example, when the sources are substantially cylindrical radioactive seeds, the shape of the cross section of the inner surface of the suture could preferably be substantially round. In an alternative embodiment, the surface could be substantially square.

Any conventional radioactive seed can be used as a radioactive source. These include, for example, the radioactive seeds disclosed in US 5,404,309, US 4,784,116, US 4,702,228, US 4,323,055 and US 3,351,049. By "seed" is meant any sealed container, for example, a metal container, which contains or encapsulates a radioisotope. Suitable biocompatible container materials include metals or metal alloys, such as titanium, gold, platinum and stainless steel; plastics such as polyester and vinyl polymers, and polyurethane, polyethylene, polyvinyl acetate polymers, compounds such as graphite; glass such as matrices comprising silicon oxide, and any other biocompatible material. Titanium and stainless steel are the preferred materials for the containers.

Radioactive seeds may also comprise a suitable radioisotope encapsulated inside a polymer or ceramic matrix.

Typical radioactive seeds are substantially cylindrical in shape. The dimensions of a typical seed can be approximately 4.5 mm long with a diameter of approximately 0.8 mm.

Any radioisotope suitable for use in brachytherapy can be used in radioactive seeds. Non-limiting examples include palladium-103, iodine-125, strontium-89, sulfur-35, cesium-131, gold-198, tulium-170, chromium-56, arsenic-73, yttrium-90, phosphorus-32 and mixtures thereof. Especially preferred are palladium.

<dl><dt>-</dt><dd> 103 and iodine - 125. More than one type of radioisotope may be present in radioactive seeds for use in the invention. </dd></dl>

Radioactive seeds and spacer members are preferably linearly loaded along the longest axis of the elongated suture member. The orientation of the radioactive seeds in relation to the suture will depend on the total size and the shape of the suture and the radioactive seeds. If the radioactive seeds are your

cylindrically, for example if they are conventional seeds, they are preferably oriented with their longitudinal axis parallel to the longitudinal axis of the same elongated suture. Preferably, the radioactive seeds are regularly separated, for example with intervals between 0.6 and 1.2 cm, preferably with intervals of 1 cm. A separation of approximately 1 cm is preferable if the sources should be implanted for the treatment of prostate cancer. The separating members of suitable lengths are located between the seeds. The number of radioactive seeds that are used for any particular application will depend on the length of the suture member used. Preferably, the radioactive member is provided as a long strip that can then be cut or fit to the desired length for a particular application by medical personnel.

Preferably, all radioactive seeds in a suture will contain the same radioisotope and / or have the same radioactive power. If more than one type or potency of the source is included in a suture, then the different radioactive seeds should be arranged in a regular pattern to allow predictable dosing.

Preferably, the radioactive member can then be inserted into a fixation to form a fixation assembly. Such fixations are disclosed in US 5,460,592. Figure 2 shows the radioactive seed2 of the radioactive member and its placement within a fixation 4. The fixation 4 allows a fixed position of the radioactive seeds 2 and of the separating members, for the subsequent manufacturing stages (stiffening), transport and also for the preparation of the segments for implantation (cutting).

Next, the fixing assembly is heated with dry heat. Dry heat causes the suture member to become stiff. This stiffening process can take place in a process of 160 ° C to 190 ° C for 60 to 90 minutes.

As an additional feature of the invention, an additional method is provided for the production of a radioactive member for use in brachytherapy, which comprises a hollow elongated bioabsorbable suture member with radioactive seeds and separating members arranged alternately therein, comprising the cited procedure the stages of:

a) providing a preferably elongated single chain bioabsorbable suture member having a

groove or longitudinal groove in it,

b) provide a plurality of radioactive seeds,

c) provide a plurality of bioabsorbable separator members, in which the separator members

they are of a different color from that of radioactive seeds and of a diameter different from that of radioactive seeds;

d) place the radioactive seeds and separating members sequentially or simultaneously within the ranu

ra in the suture member, such that the radioactive seeds and the separator members meet

train safely held within the slot.

Preferably, the groove or groove will be diametrically opposed to a flat surface of the cross section of the suture. For example, when the suture is substantially round with a flattened surface, the groove or groove will be positioned opposite this flat surface. This will allow for easier orientation during manufacturing, for example, the suture member could be oriented with the highest groove, using the flat surface as a reference, so that the sources could be easily pushed into the groove.

Preferably, the groove or groove will be shaped so that once a source is placed, it is safely retained. For example, the slot opening may be slightly narrower than the same slot and the width of the fountain, such that the fountain must be "stapled" in place by pushing it through the opening, and then retained Inside the slot For example, an elongated rail or lip can be formed along the long axis of suture within the groove and adjacent to the groove opening, so that the radioactive seeds and spacer members, once they have been pushed further beyond the rail or lip, hold subjects in position within the groove by the rail or lip. Alternatively, a series of suitably spaced projections, for example, bulges or tabs, can be provided just inside the slot opening to keep the fountains in place inside the groove. Preferably, the rails, lips or projections will be formed on both sides of the opening to the groove.

Alternatively or additionally, the radioactive seeds and the separating members may be held in place by a suitable biocompatible adhesive. For example, a drop of a suitable adhesive or resin could be placed in the groove with a fountain and then the adhesive or resin is allowed to dry or a curing process is used to dry it. Examples of biocompatible adhesives are known in the art and include epoxy adhesives such as Tra-Bond 2105, a two-component epoxy adhesive from Tra-Bond US (see Chem. Eng. News, December 8, 1997, 75 (49) P. 40); certain heptapeptides containing tyrosine and lysine and polypeptides, as disclosed in Japanese patent 05017499; certain adhesives derived from polyphenolic proteins such as those described in US 5,015,677; certain dental cement adhesives, such as an adhesive composition comprising methyl polymethacrylate (PMMA) and 5% 5- trimellitic anhydride of methacryloxyethyl with partially oxidized tibutylborane such as described in Proc. IUPAC, IUPAC, Macromol.

Symp, 28 (1982), 395; and propyl polymethacrylate, methyl polymethacrylate, butyl polymethacrylate-ethyl methacrylate), and silicone gels (see Proc. SPIE-Int. Soc. Opt. Eng. (1998), 3258, 164-168)

Alternatively or additionally, the groove edges can be deformed or pressed against each other by the application of an external force, for example by the application of a compression stage in which the upper portion of the groove edges above from the widest part of the source come into contact with the one or more heated plates, baffles, flanges or deflection members which may comprise for example, two parallel plates oriented to the suture axis and substantially perpendicular to a projected radius of the radioactive seeds and towards each other, such that the interaction with the edges of the groove causes a narrowing of the opening in the groove. This can be done after the source is placed in the slot. Alternatively, a roller, or rotating heated wheel, configured to apply compression to the grooves in the above manner, can be used. The edge of the roller or wheel can be concave to achieve this compression. Compression can be continuous.

Alternatively, heated plates can be used to bend the edges of the groove after a source has been placed in the groove. In a slotted opening of a suture material, the edges of the groove can be substantially perpendicular to the groove base. The edges of the groove can extend beyond the midpoint of the fountain, for example, beyond the widest part of the fountain (such as the diameter of a substantially circular fountain) when viewed from the end of the fountain when the source is placed in the groove. With the source in the slot, the heated plates, baffles, flanges or deflection members can be applied from above or next to the vertical edges of the slot to come into contact with the vertical edges above the widest part of the source. The heated plates then soften the vertical edges of the groove and the mechanical force causes the edges to bend over the fountain, thereby squeezing the fountain in place. Removal of the heated plates allows the bent edges to cool and therefore keep the source tightly in place in the ribbed suture.

In another embodiment, a heated roller, or rotating wheel configured to apply compression to the upper edges of the groove can be used to narrow the opening of a groove after a radioactive seed has been placed therein. A suture with one or more radioactive seeds and spacer members in place within the groove may be fed under a heated rotating wheel or roller, such that part of the wheels or roller comes into contact with the suture area adjacent to the slot opening, causing it to soften or melt and thus deform around the source to hold it in place. Preferably, the part of the roller or wheel that is in contact with the suture will have a concave surface such that the edges of the groove can be deformed or pressed against each other to form a tube, completely or partially closed, containing the sources. The contact between a given portion of the suture and the wheel or roller can be temporary, when the wheel or roller turns. Optionally, the suture may be forced to bend and follow the circumference of the wheel or roller and will be held under tension to stretch, compress or form it further.

The suture can be fed under the wheel or roller in a continuous process. Optionally, the part of the wheel or roller in contact with the suture may comprise a positive or negative mold such that contact with the suture transfers a reciprocal pattern comprising, for example, ridges or cavities, to the suture.

Alternatively or additionally, after being loaded with radioactive seeds and separating members, the suture may be enclosed within a suitable coating, for example of Vicryl ™ braiding, to keep the radioactive seeds and separator members in place within the groove. or discrete openings

At the end of the manufacturing process, the radioactive member can be cut to the appropriate length and each section can be loaded separately into a fixation, such as the fixation disclosed in US 5,460,592. The fixing assembly can be stiffened by a dry heat process as disclosed in a previous embodiment.

Optionally, the radioactive member of the invention will be protected for transport from the place of manufacture to the place of use. Preferably, after packaging, the product will be sterilized, for example, by any conventional sterilization procedure such as autoclave, gamma radiation, ethylene oxide sterilization or pulsed light sterilization. The product can then be transported from the manufacturer to the place of use as a sterile unit that, once removed from its packaging and protection, will be ready for the member to use.

The radioactive members of the invention can be used in the treatment of a variety of conditions, including head and neck cancer (including those of the mouth, lips and tongue), brain tumors, lung tumors, cervical tumors, vaginal tumors and the prostate cancer. They can be used as a primary treatment (for example in the treatment of prostate cancer or unresectable tumors) or for the treatment of residual disease after the removal of the primary tumor. They can be used simultaneously with, or in the termination of, other treatment modalities, for example, external beam radiation therapy, chemotherapy or hormonal therapy.

The radioactive members of the invention can be used alone or in combination with individual radioactive sources, for example seeds.

Also disclosed, but without being part of the present invention, there is a method of treating a condition that is sensitive to radiotherapy, for example, cancer or arthritis, especially prostate cancer, which comprises the placement of a radioactive member. comprising an elongated, essentially rigid, single chain bioabsorbable suture member with separate radioactive sources disposed therein, or adjacent to the site that must be treated in a patient for a period of time sufficient to deliver a therapeutically effective dose.

Preferably, the radioactive member can be visualized using a suitable imaging technique, preferably ultrasound imaging, in connection with the real-time dosimetry equipment.

The radioactive members of the invention can be administered to a patient by placing a suitable length of suture at the tip of a hollow needle and then placing a stylet inside the needle, as shown in Figure 3. The needle 5 can be inserted into a patient and then pull it back over the stylet leaving the suture in place. For administration procedures see, for example, the document by A. van't Riet et al., Int. J. Radiation Oncology Biol. Phys., Vol. 24, pages 555-558, 1992.

For example, the radioactive member 7 can be prepared with the required length according to the prescribed implantation plan. This preparation includes the removal of the radioactive member from the container and the sterility barrier and cutting through a separator member to achieve the prescribed length. The radioactive member cut to the prescribed length is inserted into an insertion needle, through an end connection hub 6 thereof, to the point where the complete assembly is fully within the needle 5. The radioactive member is then pushed through the hollow insertion needle, with a needle stylet, until the forward tip of the radioactive member reaches a needle plugging means, such as bone wax. The loaded insertion needle is then inserted into a prescribed treatment area of ​​a patient, for example, the prostate. The insertion needle is subsequently removed, leaving the radioactive member in the prescribed treatment area. The radioactive member is provided sterile for immediate preparation and use.

An alternative method of loading the insertion needle could include the use of a post-loading device, as shown in Figure 4. In this embodiment, the insertion needle 5 can be inserted into the prescribed treatment area of ​​a patient, for example, the prostate, before loading the radioactive limb, following the pre-operative implantation plan. The radioactive member 7, prepared with the prescribed length, is loaded into a post-load device 8, which temporarily houses the radioactive member. When required, the radioactive member is then transferred to the insertion needle into which it is attached within the connection hub of the insertion needle. A stylet is then used to advance the radioactive member through the post-loading device, into the needle, and finally into the patient.