Application of bioassay techniques to evaluate 99Mo incorporation in nuclear medicine patients

99mTc is the most widely used radionuclide in nuclear medicine. It is obtained by elution of 99Mo/99mTc generators. Depending on the quality of the generator and its integrity, 99Mo might be extracted from the column during the elution process, becoming a radionuclidic impurity in the 99mTc eluate. This fact would impart an undesired dose to the patients submitted to diagnostic procedures using 99mTc. The aim of this work is to estimate the internal effective doses in nuclear medicine patients due to the incorporation of 99Mo as a radionuclidic impurity and provide additional information about the metabolic behavior of molybdenum in humans. Results of in vivo and in vitro measurements have been compared with values obtained through the use of a standard metabolic model of molybdenum established by the ICRP using the software AIDE. Experimental data obtained in this work show the occurrence of 99Mo incorporation in nuclear medicine patients, representing an average effective dose of 0,82 μSv. Although the dose is lower than annual limit for public, it is recommended to implement a routine quality control program of radionuclidic impurity of 99Mo in 99mTc eluates. Such control should be conducted in the radiopharmacy laboratories of nuclear medicine centers. (author)