DOSIMETRY ON SUB-CELLULAR LEVEL FOR INTRACELLULAR INCORPORATED AUGER-ELECTRON-EMITTING RADIONUCLIDES: A COMPARISON OF MONTE CARLO SIMULATIONS AND ANALYTIC CALCULATIONS

A quantitative dosimetric comparison was performed between Monte Carlo (MC) simulations and analytic calculations at the (sub) cellular level (V79 cells) for four nucleus-incorporated radiochemicals (I-125/I-123/Br-77-UdR and A (IP)-I-125) and two radiochemicals that localised mainly in the cytoplasm of cells (I-125-dihydrorhodamine and (Na2CrO4)-Cr-51). A microscopic investigation around the decay site of the three DNA-incorporated radionuclides (I-125/I-123/Br-77-UdR) was also carried out. On the whole, deviations between MC and analytic calculations for the absorbed dose and dose rate to the cell nucleus were within similar to 10 %. The dose rate to the nucleus for the radiochemicals that mainly localised in the cytoplasm was greater than that for the nucleus-incorporated ones. Also evident was that the dose rate to the nucleus was approximately the same for the three DNA-incorporated radiochemicals. In contrast to the small differences found between MC and analytic calculations for the (average) absorbed dose to the nucleus, the dosimetric analysis at the microscopic level for the three DNA-incorporated radionuclides showed that the two computational approaches lead to a completely different energy deposition pattern around the decay site.