An Improved ¹⁹¹Os-^191mIr Generator for Radionuclide Angiocardiography

^191mIr is a useful tracer for radionuclide angiocardiography and may be of particular value in the evaluation of heart disease in children. It has a short half-life, a suitable photon energy, and may be obtained as a generator product by decay of its long-lived parent ¹⁹¹Os. A ¹⁹¹Os-^191mIr generator capable of providing at least 18 mCi of ^191mIr in 1.5 ml of eluant is described. ^191mIr is separated from ¹⁹¹Os by absorbing ¹⁹¹OsCI₆⁻² on an ion exchange resin and eluting with a solution of 8.7% NaCI at a pH of 2.2. The generator employs an additional resin column which is replaced to minimize ¹⁹¹Os breakthrough.