Cell survival and cytogenetic responses to 125I-UdR in cultured mammalian cells.

The relative toxicity of DNA precursors labeled with iodine-125, iodine-131, or hydrogen-3 was studied in exponentially growing Chinese hamster cells. Per decay, iodine-125 was found to be approximately 12 times as lethal as iodine-131 and 16 times as lethal as hydrogen-3. Chromosomal aberrations induced in these cells by the three radionuclides occurred with the same relative efficacy as their lethal effects.