Radiation dose from radiopharmaceuticals contaminated with molybdenum-99

Sixteen patients undergoing routine nuclear imaging procedures were injected with 99mTc-labeled radiopharmaceuticals containing 99Mo which exceeded the recommended limit of 1 microCi of 99mMo per mCi of 99mTc. The kinetics of the resulting 99Mo distribution in 14 of these patients were studied over a period of several weeks. The mean biologic half-life [T 1/2b] ranged from about 19.3 days to 11.2 days depending on the model used. Similarly, the mean radiation dose to the liver ranged from approximately 0.02 rad/microCi of 99Mo to 0.05 microCi of 99Mo.