Products and methods for brachytherapy

Abstract

Radioactive sources, preferably radioactive seeds, for use in brachytherapy comprising a radioisotope within a sealed biocompatible container, wherein at least one part of a surface of the container is roughened, shaped or otherwise treated so that it is no longer smooth. The surface treatment may enhance the ultrasound visibility of the source and/or reduce the tendency of the source to migrate once implanted in a patient's body. Preferred radioisotopes are palladium-103 and iodine-125.

1 . A radioactive source for use in brachytherapy comprising a radioisotope within a sealed biocompatible container, wherein at least one part of a surface of the container is roughened, shaped or otherwise treated so that it is no longer smooth.  
     
     
         2 . A radioactive source as claimed in  claim 1  wherein the roughened, shaped or otherwise treated surface is the outer surface of the container.  
     
     
         3 . A radioactive source as claimed in  claim 1  or  claim 2  where the roughened, shaped or otherwise treated surface is effective to enhance ultrasound visibility.  
     
     
         4 . A radioactive source as claimed in any of  claims 1  to  3  wherein the container comprises gold, titanium, platinum or stainless steel.  
     
     
         5 . A radioactive source as claimed in any of  claims 1  to  4  wherein the roughened, shaped or otherwise treated surface comprises grooves, scratches, abrasions or depressions.  
     
     
         6 . A radioactive source as claimed in  claim 5  wherein the grooves, scratches, abrasions or depressions are arranged randomly on the surface.  
     
     
         7 . A radioactive source as claimed in  claim 5  wherein the grooves, scratches, abrasions or depressions are arranged in a regular pattern.  
     
     
         8 . A radioactive source as claimed in any of  claims 1  to  7  wherein the roughened, shaped or otherwise treated surface comprises ridges, bumps, undulations or serrations upstanding from the surface.  
     
     
         9 . A radioactive source as claimed in any of  claims 1  to  8  wherein the radioisotope is palladium-103 or iodine-125.  
     
     
         10 . A method for the preparation of a radioactive source as claimed in any of  claims 1  to  9  which comprises roughening, shaping or otherwise treating an exterior surface or part of an exterior surface of the biocompatible container to thereby provide irregularities or discontinuities of dimensions in the exterior surface.  
     
     
         11 . A method for the preparation of a radioactive source as claimed in any of  claims 1  to  9  which comprises: 
 (i) roughening, shaping or otherwise treating a surface or part of a surface of a biocompatible container material to provide irregularities or discontinuities of dimensions;  
 (ii) loading a radioisotope into the biocompatible container material of step (i); and  
 (iii) sealing the biocompatible container.  
 
     
     
         12 . A method as claimed in  claim 10  or  claim 11  where the surface roughening or shaping is achieved by forcing through a ridged or serrated die, or a threading device, milling, roughening by mechanical friction, etching, crimping, or wet or dry blasting.  
     
     
         13 . A method as claimed in  claim 10  or  claim 11  where the surface roughening or shaping involves selective dissolution of one component of a composite biocompatible material.  
     
     
         14 . A method as claimed in  claim 13  wherein the composite material is a ceramic composite, a polymer blend, or a polymeric or ceramic material with soluble materials entrained therein.  
     
     
         15 . A method as claimed in any of  claims 11  to  14  where the surface roughening or shaping is applied to the exterior surface of the biocompatible container material.  
     
     
         16 . A method of treatment of a condition which is responsive to radiation therapy, which comprises the temporary or permanent placement of a radioactive source comprising a radioisotope within a sealed biocompatible container, wherein at least one part of a surface of the container is roughened, shaped or otherwise treated to thereby provide irregularities or discontinuities of dimensions, at the site to be treated within a patient for a sufficient period of time to deliver a therapeutically effective dose.  
     
     
         17 . A method of treatment as claimed in  claim 16  wherein the condition to be treated is cancer, arthritis or restenosis.  
     
     
         18 . A method of treatment as claimed in  claim 16  or  claim 19  wherein the condition is prostate cancer.  
     
     
         19 . A method of treatment as claimed in any of  claims 16  to  18  whereby the irregularities or discontinuities enhance the ultrasound visibility of the source.  
     
     
         20 . A composition which comprises a multiplicity of radioactive sources as claimed in any of  claims 1  to  9  within a substantially linear, biodegradable material.  
     
     
         21 . A composition as claimed in  claim 20  where the biodegradable material is semi-rigid.