Simulation of ultrasoft X-rays induced DNA damage using the Geant4 Monte Carlo toolkit

In this study, the total yields of SSB and DSB induced by monoenergetic electrons with energies of 0.28–4.55 keV, corresponding to ultrasoft X-rays energies, have been calculated in Charlton and Humm volume model using the Geant4-DNA toolkit and compared with theoretical and experimental data. A reasonable agreement between the obtained results in the present study and experimental and theoretical data of previous studies showed the efficiency of this model in estimating the total yield of strand breaks in spite of its simplicity. Also, it has been found that in the low energy region, the yield of the total SSB remains nearly constant while the DSB yield increases with decreasing energy. Moreover, a direct dependency between DSB induction, RBE value and the mean lineal energy as a microdosimetry quantity has been observed. In addition, it has become clear that the use of the threshold energy of 10.79 eV to calculate the total strand breaks yields results in a better agreement with the experiments, while the threshold of 17.5 eV shows a big difference.