RBE-LET relationship for proton and alpha irradiations studied with a nanodosimetric approach

Relative Biological Effectiveness (RBE) values are used to characterise the biological efficiency of different radiation qualities relative to photon irradiations. The RBE-high linear energy transfer (LET) relation for ion irradiations presents general features that the authors propose to look at using a nanometric description of the energy deposition of these ion irradiations (protons and alphas of different energies). In this work, the simulation of the energy transfer points in the tracks was made by Monte Carlo method using the Geant4-DNA processes and a nanometric description of the target of interest for studying biological effects, the DNA molecule. Results were obtained concerning the sensitive volume to be considered for direct DNA clustered damages that could be related to late biological effects.