THE STANDARDIZATION OF THE POTENTIAL BONE PALLIATION RADIOPHARMACEUTICAL SN-117M(+4)DTPA

Solutions containing the potential bone pain palliation radionuclide S n-117m, in chloride form and as a diethylenetriaminepentaacetate (DTPA ) complex, have been standardized by 4 pi beta liquid scintillation (L S) spectrometry and 4 pi gamma-ray spectrometry. Massic activities of the stock solutions were measured in order to determine dose calibrato r settings for the solutions using commercial dose calibrators. Excell ent agreement in the measurement of solution massic activity between t he two techniques was achieved. The massic activity of (SnCl4)-Sn-117m stock solution was found to be 38.62+/-0.23 MBq g(-1) and 38.81+/-0.9 4 MBq g(-1) with LS spectrometry and 4 pi gamma-ray spectrometry respe ctively. The respective values of the massic activity of the (117m)SnD TPA stock solution with LS spectrometry and 4 pi gamma-ray spectrometr y were 39.35+/-0.23 MBq g(-1) and 39.70+/-0.96 MBq g(-1). Impurities w ere analyzed in several solutions and found to have emission rates on the order of 10(-4) to 10(-6) of the rate of the Sn-117m emission at t he end-of-bombardment. The largest impurities dame from Sn-113 and Sn- 125, the activation products of isotopic impurities present in the Sn- 117 target. The relative proportions of the various impurities were fo und to be highly dependent upon the source of Sn-117 target material. The implications of choice of half-life used in the decay correction o f Sn-117m are discussed. Published by Elsevier Science Ltd.