Demonstration of a 228Ra/228Ac isotope generator.

An isotope generator to produce 228Ac from 228Ra was developed using a cation exchange resin column eluted with an acetate-diethylenetriaminpentaacetic acid buffer. The elution behavior of 228Ac on the column was studied with solutions of various pHs to select the optimal conditions. Two identical isotope generators were eluted for 47 days with over 100 mL of eluant with no detectable 228Ra breakthrough and high 228Ac yields (∼95%). The separation requires only biocompatible reagents and is performed at pH 4.6, conditions suitable for radiopharmaceutical studies of Ac.