放射性医薬品による内部被曝線量に対する不純物核種の寄与評価

抄録

The additional absorbed radiation doses to total body from radioactive impurities in radiopharmaceuticals were estimated for a total of 10 samples (i.e., ^99mTc generator eluates, ^99mTc solutions, ⁶⁷Ga, ^81mKr generator eluates, ¹¹¹In, ¹²³I, ²⁰¹Tl, ⁷⁵Se, ¹⁹⁷Hg, ¹⁹⁸Au) selected from commonly used radiopharmaceuticals. The radioactive impurities in radiopharmaceuticals used in this estimation were previoulsy identified. The radiation doses were calculated according to the MIRD procedures, assuming each radionuclide to be uniformly distributed throughout the body. In the case of the cyclotron-produced radioisotopes and ¹⁹⁸Au, the additional total body absorbed doses from impurities were found to be rather high: 280% for ¹²³I, 55% for ^81mKr, 5% for ¹⁹⁸Au, 4% for ¹¹¹In and 2% for ²⁰¹Tl. The absorbed doses due to impurities in the other radioisotopes were less than 1%.