Purification and Labeling Strategies for 68Ga from 68Ge/68Ga Generator Eluate

Abstract

For successful labeling, (68)Ge/(68)Ga generator eluate has to be concentrated (from 10mL or more to less than 1mL) and to be purified of metallic impurities, especially Fe(III), and (68)Ge breakthrough. Anionic, cationic and fractional elution methods are well known. We describe two new methods: (1) a combined cationic-anionic purification and (2) an easy-to-use and reliable cationic purification with NaCl solution. Using the first method, (68)Ga from 10mL generator eluate was collected on a SCX cartridge, then eluted with 1.0mL 5.5M HCl directly on an anion exchanger (30mg AG1X8). After drying with a stream of helium, (68)Ga was eluted with 0.4mL water into the reaction vial. We provide as an example labeling of BPAMD. Using the second method, (68)Ga from 10mL generator eluate was collected on a SCX cartridge, then eluted with a hydrochloric solution of sodium chloride (0.5mL 5M NaCl, 12.5μL 5.5M HCl) into the reaction vial, containing 40μg DOTATOC and 0.5mL 1M ammonium acetate buffer pH 4.5. After heating for 7min at 90°C, the reaction was finished. Radiochemical purity was higher than 95% without further purification. No (68)Ge breakthrough was found in the final product.