Selenium-72 formation via natBr(p,x) induced by 100 MeV Protons: Steps towards a novel 72Se/72As generator system

Abstract

Selenium-72 production by the proton bombardment of a natural NaBr target has been successfully demonstrated at the Los Alamos National Laboratory Isotope Production Facility (LANL-IPF). Arsenic-72 (half life 26h) is a medium-lived positron emitting radionuclide with the major advantage of being formed as the daughter of another “generator” radioisotope (Se-72, 8.5 d). A 72Se/72As generator would be the preferred mechanism for clinical utilization of 72As for positron emission tomography (PET). No portable 72Se/72As generator system has been demonstrated for convenient, repeated 72As elution (“milking”). In this work, we describe 72Se production and recovery from irradiated NaBr targets using a 100MeV proton beam. We also introduce an 72As generator principle based on 72Se chelation followed by liquid–liquid extraction, which will be transferred to a solid-phase sorption/elution system.