Evaluation of cumulated absorbed dose and RBE from internal irradiation by 125IUdR incorporated into DNA of B16 melanoma cells

On the basis of study on kinetics of 125IUdR uptake using micronucleus rates as biological end point and 60Co γ-rays as reference radiation, the cumulated absorbed dose of internal irradiation and RBE of 125IUdR incorporated into DNA of B16 melanoma cells were evaluated. The results demonstrated that the rates of 125IUdR uptake increased linearly with the increase of extracellular radioactive concentration of 125IUdR and incubation period. The total micronucleus rates and the micronucleated cell rates both increased with the increase of the rates of 125IUdR uptake. Their regression equations were Y1 0.0895 + 0.029 X and Y2 = 0.0776 + 0.021 X respectively. The RBE were 4.9 and 5 as compared with 60Co γ-rays. Calculation of the RBE of 125IUdR at normal temperature was attempted in this study