Calculation of Radiation-Induced DNA Damage Efficiency: Analysis of Uncertainties

— Computer simulations of the DNA damage are widely used due to their large application area. The computational methods to predict DNA breaks are based on molecular concepts about the formation of breaks, the geometric structure of DNA, and information about the distribution of absorbed energy in a DNA molecule. Intercomparison of the accuracy of calculations performed by different schemes is commonly difficult, since the calculations employ different prerequisites, postulates, and algorithms. The same applies to determination of the parameters of the DNA lesion models due to scatter of experimental data. A comparative analysis of predictions is performed based on two basic models of the DNA structure, that is, the molecular and volume, which use different assumptions with respect to the formation mechanism of single- and double-strand DNA breaks, in the case of irradiation of DNA molecules with protons and α-particles. Calculations of the efficiency of radiation-induced DNA damage, considering contribution of the direct effect, molecular structure of DNA, and stochastic structure of charged tracks show the dependence of the frequency of occurrence of DNA damage on the model parameters. The parameter domains were found, within which predictions generated by the models are either in agreement or differ from one another.