Simulation of strand breaks induced in DNA molecule by radiation of proton and Secondary particles using Geant4 code

Radiotherapy using various beams is one of the methods for treating cancer, Hadrons  used   to  treat cancers  that  are  near critical organs. The most important part of the cell that is damage by ionizing radiation is DNA. In this study, damages induced in the  genetic material of  living cells (DNA) defined by  the  atomic model from the  protein data bank (PDB) have been studied by  radiation of monoenergetic protons and its secondary particles using  Geant4 code. The total SSB yield is independent of energy of incident particle. The total DSB yield is increase with increasing of  incident particle LET. The ratio of total inelastic events to absorbed dose for primary protons as well as its  secondary particles is independent of energy. The contribution of  secondary particles in the formation  of  single-strand  breaks and double-strand breaks have been calculated. The DSB yield generated by secondary particles is increase with decreasing the energy of the incident particle and the contribution of  secondary particles to the generate of double-strand break for energies less than 5 Mev  is greater than their contribution to the creation of single-strande breaks. The ratio of double-strand breaks to single- strand breaks have been reduced by increasing  the energy of   the radiation particle.