SIMULATION OF EARLY RADIATION-INDUCED DNA DAMAGE ON DIFFERENT TYPES OF CELL NUCLEI.

This work presents a comparison of simulated early radiation-induced DNA damage represented by yields of double-strand breaks (DSB) in three different human cell nuclei geometries representing fibroblasts, lymphocytes and endothelial cells for protons and alpha particles of different energies and for different irradiation configurations. Each cell nucleus model includes a multi-scale description of the DNA target from the molecular level to the whole human genome representation (6 Gbp) in the G0/G1 phase of the cell cycle and was generated with the DnaFabric software. The three nuclei differ in shape, volume, and therefore DNA density. A calculation chain based on Geant4-DNA that takes into account the physical, physico-chemical and chemical stages was used to simulate the irradiation of the different cell nuclei. Results show an increase of DSB/primary/mu m with an increase of DNA density and an increase of DSB/Gy/Gbp with an increase of the cell nucleus volume which indicates that the cell nucleus shape and size have an impact on early DNA damage, which may play a role in latter effects.