Radiochemical separation of Ra from U and Th sources for Ra/Pb/Bi generator.

The application of diagnostic and therapeutic radionuclides in nuclear medicine has grown significantly and has translated into the increased interest in radionuclide generators and their development. Ra and its shorter-lived daughters, Pb and Bi, are very interesting radionuclides from Targeted Alpha Therapy point of view for treatment of small cancers or metastatic forms. The purpose of the present work was to develop a simple generator for rapid elution of carrier-free Ra from U or Th sources by radiochemical separation based on extraction chromatography with the utilization of a home-made material. The bis(2-ethylhexyl) hydrogen phosphate (HDEHP) extractant was immobilized on polytetrafluroethylene (PTFE) grains and its ability to selectively adsorb U and Th, with simultaneous high elution recovery of Ra, was checked over few years. The Ra was quantitatively eluted with small volume (3-5 mL) of 0.1 M HNO with low breakthrough (<0.005%) and was used for further milking of Bi and Pb from DOWEX 50WX12 by 0.75 M and 2.0 M HCl, respectively. The elaborated here methods allowed high recovery of Ra, Pb and Bi radionuclides and their application in radiolabeling of various biomolecules.