Apparatus and methods for radiotherapy

Abstract

The invention provides the use of a radiation source which is a low energy X-ray emitter, e.g. with an energy of emission of the principal photon in the range of 20 to 100 keV, preferably 20 to 40 keV and with a half life of 10 to 100 days, preferably 15 to 70 days, for the treatment of restenosis. Suitable radioisotopes include palladium-103, dysprosium-159, samarium-145, cadmium-109, ytterbium-169 and preferably iodine-125. High activity radioactive bodies and sources comprising such radioisotopes, and methods for the manufacture of such sources, are also disclosed.

1 - 15 . (canceled)  
   
   
       16 . A method for immobilising radioactive iodide ions on the surface of a metal or metal coated support, the method comprising forming a layer of an insoluble metal salt on the surface of the support, and replacing anions in the insoluble salt with radioactive iodide ions by ion exchange, wherein the ion exchange is carried out on a batch of 1 to 10 supports.  
   
   
       17 . A method as claimed in  claim 16  wherein the ion exchange is carried out on each support individually.  
   
   
       18 . A method as claimed in  claim 16  wherein the metal is silver.  
   
   
       19 . A method as claimed in  claim 18  wherein the insoluble salt is silver bromide or silver chloride.  
   
   
       20 . A method as claimed in  claim 16  wherein the support is agitated during the method.  
   
   
       21 . A method for the manufacture of radioactive beads, said method comprising the steps of: 
 a) preparing a batch of a suitable ion exchange resin beads by soaking the beads in a solution containing an anion or cation replaceable by the desired radioisotope, and then washing the batch with water until the wash water is free of such anions or cations;    b) drying the batch and placing a bead thereof in each of one or more individual reaction wells;    c) placing an equal volume of a solution comprising anions or cations of the desired radioisotope in each reaction well;    d) leaving each bead in the radioisotope solution for a predetermined length of time so that the radioisotope is absorbed by each bead; and    e) removing the supernatant, washing and drying the beads.    
   
   
       22 . A method as claimed in  claim 21  wherein the radioisotope is iodine-125.  
   
   
       23 . A method as claimed in  claim 21  wherein the ion exchange resin is resistant to degradation by radiation during the method.  
   
   
       24 - 30 . (canceled)