geant4 modeling of cellular dosimetry of ^188re: comparison between geant4 predicted surviving fraction and experimentally surviving fraction determined by mtt assay

Background: the importance of cellular dosimetry in both diagnostic and radiation therapy is becoming increasingly recognized. objective: this study aims to compare surviving fractions, which were predicted using geant4 and contained three types of cancer cell lines exposed to ^188re with the experimentally surviving fraction determined by mtt assay.material and methods: in this comparative study, geant-4 was used to simulate the transport of electrons emitted by ^188re from the cell surface, cytoplasm, nucleus or medium around the cells. the nucleus dose per decay (s-value) was computed for models of single cell and random monolayer cell. geant4 computed survival fraction (sf) of cancer cells exposed to ^188re was compared with the experimental sf values of mtt assay. for single cell model, geant4 s-values of nucleus to nucleus were consistent with values reported by goddu et al. (ratio of s-values by analytical techniques vs. geant4 = 0.811–0.975). geant4 s-values of cytoplasm and cell surface to nucleus were relatively comparable to the reported values (ratio =0.914–1.21). for monolayer model, the values of scy→n and scs→n, were greater compared to those for model of single cell (2%–25% and 4%–38% were larger than single cell, respectively).the geant4 predicted sf for monolayer mcf7, hela and a549 cells was in agreement with the experimental data in 10μci activity (relative error of 2.29%, 2.69% and 2.99%, respectively).conclusion: geant4 simulation with monolayer cell model showed the highest accuracy in predicting the sf of cancer cells exposed to homogeneous distribution of 188re in the medium.