Assessment of radiation-induced DNA damage caused by the incorporation of 99mTc-radiopharmaceuticals in murine lymphocytes using single cell gel electrophoresis.

The DNA damage induced by the 99mTc-radiopharmaceuticals incorporation to the cell was determined by the single-cell gel electrophoresis in murine lymphocytes in vitro. The 99mTc-hexamethyl-propylene amine oxime (99mTc-HMPAO) and 99mTc-2, 5-dihydroxybenzoic acid (99mTc-gentisic acid) induced nearly 100% of cells with breaks and/or alkali labile sites, which is explained by the action of the Auger electrons produced by the decay of the 99mTc. These results agree with the doses of 1.6 and 1.0 Gy estimated by subcellular dosimetry for 99mTc-HMPAO that is incorporated in the cytoplasm, and the 99mTc-gentisic acid, which remains bonded to the cell membrane, respectively. The results imply that Auger electrons are able to cause important DNA damage, when the radionuclide is incorporated in the range of a few microns from the nuclei.