Radiochemical separation of76,77Br and66,67Ga from irradiated ZnSe targets using anion-exchange chromatography

Abstract

AbstractThe separation of no-carrier-added (n.c.a.) radiobromine and radiogallium from an irradiated ZnSe target was developed using anion-exchange chromatography. The adsorption behaviour of n.c.a. radiobromine, n.c.a. radiogallium, and macro amounts of zinc and selenium towards the anion-exchange resin Dowex 1 × 10, in Cl−and OH−form, was investigated. Radiobromide was strongly adsorbed on the resin at a low KOH concentration, while n.c.a. radiogallium, zinc and selenium were weakly adsorbed. The adsorbed n.c.a. radiobromine was recovered by 0.2 M H2SO4, followed by addition of KOH, evaporation and redissolution of residue. Finally a K∗Br solution was obtained containing about 93 ± 3% of the n.c.a. radiobromine loaded onto the column. The chloride strength in the residual solution (containing n.c.a. radiogallium and macro amounts of zinc and selenium) was increased to 4 M and then loaded onto the Dowex 1 × 10 column in Cl−form. Radiogallium (n.c.a.) was adsorbed while zinc and selenium were not. About 94 ± 2% of the n.c.a. radiogallium loaded on the column was then eluted with 0.1 M HCl. Using this method76,77Br and66,67Ga could be obtained in high purity. The radionuclidic purity of the66Ga/67Ga theragnostic pair is high enough for use in medicine. In the case of the76Br/77Br pair, however, highly enriched76Se and77Se would be needed as target materials, in order to achieve the required radionuclidic purity.