(67)Ga and (68)Ga purification studies: preliminary results.

The positron emission tomography technique is very useful for diagnosis of several diseases. (68)Ga is a positron emitter with half-life of 67.7 min. As it is available from (68)Ge/(68)Ga generator systems, it is not necessary to have a nearby cyclotron. However, the eluate from commercial generators contains high levels of metallic impurities, which compete with (68)Ga in biomolecular labeling. Thus, a subsequent purification step is needed after generator elution. Here we present the results of two different methods developed for handmade purification of (68)Ga and (67)Ga for subsequent radiolabeling of biomolecules. Two purification methods were employed. The first one uses a cation exchange resin, and (68)Ga is eluted with a solution of acetone/acid. The second method of purification is performed by column chromatography solvent extraction, with (68)Ga recovery in deionized water. The best result was achieved with cationic resin AG50W-X8 (>400 mesh). However, the resin is not commercially available. The extraction chromatography column based on absorption of diisopropyl ether in XAD-16 is the most promising purification method. Although the levels of (68)Ga recovery and purification were smaller with the cationic resin method, its advantage is the (68)Ga recovery in deionized water.