A no-carrier-added72Se/72As radionuclide generator based on solid phase extraction

Abstract

Summary72As-labelled radiopharmaceuticals could be a valuable resource for Positron Emission Tomography (PET). In particular, the long half-life of72As (T1/2= 26 h) facilitates the observation of long-term physiological or metabolic processes, such as the enrichment and distribution of antibodies in tumor tissue. This work describes the primary radiochemical separation of no-carrier-added (nca)72Se from cyclotron irradiated germanium targets and the development of a polystyrene type solid-phase extraction based72Se/72As radionuclide generator, avoiding the addition of any selenium carrier. The irradiated germanium target is dissolved in HFconcand selenium is reduced with hydrazine dihydrochloride. The nca72Se(0)is adsorbed on a solid-phase extraction cartridge, representing the generator column. The72As is eluted using various aqueous solvents with 40–60% yield and < 0.1%72Se content. To be able to study the radiopharmaceutical arsenic chemistry, subsequent chemical modification of the nca72As eluates to nca [72As]AsI3provides a versatile radioarsenic labelling synthon.