An improved 191Os/191mIr generator using a hybrid anion exchanger.

Iridium-191m is an attractive radionuclide for first-pass radionuclide angiography, but development of an 191Os/191mIr generator with high 191mIr yield has proven difficult. The use of trans-dioxobisoxalatoosmate(VI) as a parent species results in a higher initial yield (20 to 25%/mL), but the yield decreases over time. Using an anion-exchange column of tridodecylmethylammonium chloride-treated silica gel and AG MP-1 resin, we have developed an improved 191Os/191mIr generator with higher initial yield (25 to 30%/mL) and a slower rate of decrease than the previous design.