Development of an electrochemical 90Sr-90Y generator for separation of 90Y suitable for targeted therapy

Y-90 of high specific activity and very high radionuclidic purity (>99.998%) is essential for targeted therapy Since the current methods used for the preparation of Y-90 from Sr-90 are not adaptable for use in a central/hospital radiopharmacy, a simple Sr-90-Y-90 generator system based on electrochemical separation technique was developed. Methods: Two-cycle electrolysis procedure was developed for separation of Y-90 from Sr-90 in nitrate solution. The first electrolysis was performed for 90 min in Sr-90(NO3)(2) feed solution at pH 2-3 at a potential of -2.5V with 100-200 mA current using platinum electrodes. The second electrolysis was performed for 45 min in 3 mM HNO3 at a potential of -2.5V with 100 mA current. In this step, the cathode from the first electrolysis containing Y-90 was used as anode along with a fresh circular platinum electrode as cathode. The Y-90 deposited on the circular cathode after the second electrolysis was dissolved in acetate buffer to obtain Y-90 acetate, suitable for radiolabeling. Results: >96% recovery of Y-90 could be achieved in each cycle, with an overall decay corrected yield of >90%. The recovered Y-90 had high radionuclidic purity with barely 30.2 +/- 15.2 kBq (817 +/- 411 nCi) of Sr-90 per 37 GBq (1 Ci) of Y-90 (0.817 +/- 0.411 ppm). Consistent and repeated separation could be demonstrated using up to 1.85 GBq (50 mCi) of Sr-90. The generator was named "Kamadhenu," the eternally milk-yielding Indian mythological cow. Conclusions: A technique suitable for adaptation at central radiopharmacies for obtaining therapeutic quantities of pure Y-90 has been developed. (c) 2008 Elsevier Inc. All rights reserved.