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

⁷²As-labelled radiopharmaceuticals could be a valuable resource for Positron Emission Tomography (PET). In particular, the long half-life of ⁷²As (T_1/2 = 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 based ⁷²Se/⁷²As radionuclide generator, avoiding the addition of any selenium carrier. The irradiated germanium target is dissolved in HF_conc and selenium is reduced with hydrazine dihydrochloride. The nca ⁷²Se⁽⁰⁾ is adsorbed on a solid-phase extraction cartridge, representing the generator column. The ⁷²As 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 nca ⁷²As eluates to nca [⁷²As]AsI₃ provides a versatile radioarsenic labelling synthon.