Patent Number: 
Section: claims

1. A method of forming a low-dose (LDR) brachytherapy device, the method comprising:forming a plurality of substrates having a water-insoluble form of a radioactive material thereon; andpositioning the plurality of substrates on a carrier core; andforming a medical device from the carrier core and the plurality of substrates, wherein forming the plurality of substrates having the water-insoluble form of the radioactive material thereon comprises:depositing a solution comprising a soluble form of a radioactive material on a substrate; andconverting the soluble form of the radioactive material to a water-insoluble form of the radioactive material on the substrate, andwherein converting the soluble form of the radioactive material to a water insoluble form of the radioactive material comprises exposing the substrate and the water-soluble form of the radioactive material to plasma thereby decomposing the soluble form of the radioactive material to a water-insoluble form of the radioactive material. 2. The method of claim 1, wherein the plasma comprises hydrogen plasma and/or an oxygen plasma. 3. The method of claim 2, wherein the hydrogen or oxygen plasma is at atmospheric pressure or in a partial vacuum. 4. The method of claim 2, wherein the soluble form the radioactive material comprises a salt of Pd-103. 5. The method of claim 4, wherein the salt of Pd-103 comprises tetraaminopalladium chloride. 6. The method of claim 1, wherein the substrate comprises a polymer substrate. 7. The method of claim 1, wherein forming a medical device comprises enclosing the substrates, the carrier core and the water-insoluble form of the radioactive material with a biocompatible material. 8. The method of claim 1, wherein depositing a solution comprising a soluble form of a radioactive material on a substrate comprises depositing an array of spaced-apart globules of the soluble form of the radioactive material on the substrate. 9. The method of claim 8, wherein the substrate comprises micro-wells, and the array of spaced-apart globules are deposited in at least some of the micro-wells on the substrate. 10. The method of claim 8, wherein the substrate is substantially planar. 11. The method of claim 8, wherein forming a medical device from the carrier core and the plurality of substrates comprises:adhering a polymer sheet on the substrate and the water-insoluble form of the radioactive material; andsizing elongated portions of the carrier core to thereby form a brachytherapy strand. 12. The method of claim 11, wherein forming a medical device from the substrate and the water-insoluble form of the radioactive material comprises:positioning the brachytherapy strand in a biocompatible tube;filling the tube with a curable thermoplastic resin; andcuring the thermoplastic resin such that the radioactive material is sealed. 13. The method of claim 1, wherein the solution comprises a soluble form of Pd-103 comprising [Pd(NH3)4]Cl2 and/or PdCl2. 14. The method of claim 13, wherein the solution comprises [Pd(NH3)4]Cl2 dissolved in ammonium hydroxide (NH4OH) and/or PdCl2 dissolved in HCl. 15. The method of claim 1, wherein the radioactive material comprises I-125. 16. The method of claim 1, further comprising coating the plurality of substrates with a biocompatible coating. 17. The method of claim 16, wherein the biocompatible coating comprises a polyurethane sleeve. 18. The method of claim 17, wherein the polyurethane sleeve has a thickness greater than 150 micrometers. 19. The method of claim 1, wherein depositing the solution comprises depositing discrete, spaced-apart globules of the solution using a solenoid dispensing system having a controlled pressurized fluid source, a micro-syringe pump and/or micropipette. 20. The method of claim 19, wherein a volume for each of the globules is between 5 and 500 nanoliters. 21. The method of claim 19, further comprising depositing the respective volumes of the globules to an accuracy of 10% of an intended volume. 22. The method of claim 19, wherein the globules are spaced apart by about 500-1000 μm. 23. The method of claim 1, wherein each of the substrates is an elongated body. 24. The method of claim 1, wherein depositing a solution comprising a soluble form of a radioactive material on a substrate comprises depositing spaced-apart globules of the soluble form of the radioactive material, wherein the globules have a volume of about 30-200 nanoliters.