Patent Number: 046631291
Section: claims

1. In an isotopic generator system, a method of using thorium-228 supply material disposed in a raiologically controlled portion of the system for producing radionuclides of bismuth-212 and lead-212 in a cation exchange resin bed, comprising the steps of: (a) separating radium-224 from a solution of thorium-228 supply material in an approximately 8 molar nitric acid in said radiologically contained portion by passing said solution through a strongly basic anion exchange resin;  (b) transferring said radium-224 to said cation exchange resin bed from said radiologically contained portion;  (c) producing said bismuth-212 and lead-212 radionuclides by decay of the Radium-224 in said cation-exchange resin bed; and  (d) eluting said bismuth-212 and lead-212 from said cation exchange resin bed with acid.  passing said solution through said anion exchange resin and providing an output from said exchange column;  filling an evaporation unit with said output from said exchange column;  producing a dried compound of said radium-224 by evaporating in said evaporation unit said output from said exchange column; and  charging a liquid into said evaporation unit to dissolve said radium-224 compound.  radium supply means for providing radium-224 starting material, said radium supply means comprising thorium-228 supply material;  means for separating radium-224 from a solution of thorium-228 supply material in an approximately 8 Molar nitric acid in a radiologically contained portion of said system by passage of said solution through a strougly basic anion exchange resin;  means for transferring said radium-224 to a cation exchange resin bed from said radiologically contained portion;  means for producing said bismuth-212 and lead-212 radionuclides in said cation exchange resin bed; and  eluting said bismuth-212 and lead-212 from said cation exchange resin bed with acid. 2. The method as defined in claim 1 further including the step of selectively withdrawing from the cation exchange resin bed portion at least one radionuclide selected from the group consisting of bismuth-212 and lead-212. 3. The method as defined in claim 1 wherein said step of separating radium-224 comprises: 4. The method as defined in claim 3 wherein said liquid is a member selected from the group consisting of water and 0.1 molar HCl. 5. The method as defined in claim 3 wherein said anion exchange resin comprises quaternary ammonium functional groups attached to a styrene divinyl benzene copolymer lattice. 6. The method as defined in claim 3 wherein said thorium-228 supply material comprises a 8M nitric acid solution of thorium-228 and daughter materials and said radium-224 compound comprises radium-224 nitrate. 7. The method as defined in claim 2 wherein said step of selectively withdrawing bismuth-212 comprises inputting to said cation exchange resin bed a first acid selected from the group consisting of hydrochloric, hydroiodic, hydrobromic, nitric and ascorbic acid. 8. The method as defined in claim 7 wherein said step of selectively withdrawing comprises preferentially removing said bismuth-212 and subsequently inputting to said cation exchange resin bed a second acid to remove preferentially said lead-212, said second acid selected from the group consisting of hydrochloric, hydroiodic and hydrobromic acid, and having a higher molarity than said first acid. 9. The method as defined in claim 8 wherein said first acid comprises hydrochloric acid with a molarity from about 0.25 to 1.0 and said second acid comprises hydrochloric acid with a molarity from about 1 to 6. 10. The method as defined in claim 8 wherein said first acid comprises hydroiodic acid with a molarity from about 0.05 to 0.20 and said second acid comprises hydroiodic acid with a molarity from about 0.02 to 1.0. 11. The method as defined in claim 7 wherein said first acid comprises nitric acid with a molarity from about 3 to 5. 12. The method as defined in claim 7 wherein said first acid comprises ascorbic acid with a molarity from about 1 to 2. 13. An isotopic generator system for providing bismuth-212 and lead-212 radionuclides for selective removal and therapeutic medical use, comprising: