Sodium-iodide symporter positive cells after intracellular uptake of (99m)Tc versus α-emitter 211At. Reduction of clonogenic survival and characterization of DNA damage.

Purpose: We evaluated the DNA damaging potential of Auger electrons emitted in the decay of (99m)Tc compared to α-particles of 211At.

Material And Methods: The impact of (99m)Tc and 211At was monitored in a NIS-expressing rat thyroid cell model PCCl3 with varying, yet defined intra- and extracellular radionuclide distribution (using ± perchlorate). The radiotoxicity of (99m)Tc and 211At was studied by the comet assay under neutral and alkaline conditions and colony formation.