Room: ePoster Forums
Purpose: The main target of ionizing radiation with cells is the nuclear DNA. Ionizing radiation induces damage in the DNA in the form of double strand breaks (DSB), single strand breaks (SSB), and base lesions (BL). The Damage to the DNA may appear in different levels of complexity. The frequency of damage as well as the damage complexity variate as a function of LET. In this study we employed Monte Carlo Track Structure Simulation to study the frequency and complexity of damage as a function of particle type and Energy.
Methods: The track structure simulation considered both direct and indirect radiation interactions with DNA. The direct interaction is mainly due to ionization and excitation of water, and the indirect interaction is due to the interaction of OH radicals with the DNA. The simulations were performed for alpha, proton, and electron for energies ranging from 2 to 20 MeV, 1 to 20 MeV, and 0.1 to 4.5 keV,respectively. Frequency of Damage and Damage complexity was recorded for each simulation.
Results: In order to verify the simulation results, DSB frequency were compared to experimental results and previous simulations. The yield of DSB very nearly constant as a function of LET for alpha particles. The simulation results showed that the DSB complexity increases as a function of LET for electron, proton and alpha particles.
Conclusion: The current simulations show better agreement with experimental data in comparison to previous Monte Carlo simulations. The enhancement in relative biological effectiveness (RBE) for high LET radiation is correlated to the complexity of DSB.