Monte Carlo Simulation-Based Calculations of Complex DNA Damage for Incidents of Environmental Ionizing Radiation Exposure

Abstract

In this paper, we present a useful Monte Carlo (MC)-based methodology that can be utilized to calculate the absorbed dose and the initial levels of complex DNA damage (such as double strand breaks-DSBs) in the case of an environmental ionizing radiation (IR) exposure incident (REI) i.e., a nuclear accident. Our objective is to assess the doses and complex DNA damage by isolating only one component of the total radiation released in the environment after a REI that will affect the health of the exposed individual. More specifically, the radiation emitted by radionuclide 137Cs in the ground (under the individual’s feet). We use a merging of the Monte Carlo N-Particle Transport code (MCNP) with the Monte Carlo Damage Simulation (MCDS) code. The DNA lesions have been estimated through simulations for different surface activities of a 137Cs ground-based γ radiation source. The energy spectrum of the emitted secondary electrons and the absorbed dose in typical mammalian cells have been calculated using the MCNP code, and then these data are used as an input in the MCDS code for the estimation of critical DNA damage levels and types. As a realistic application, the calculated dose is also used to assess the Excess Lifetime Cancer Risk (ELCR) for eight hypothetical individuals, living in different zones around the Chernobyl Nuclear Power Plant, exposed to different time periods at the days of the accident in 1986. We conclude that any exposition of an individual in the near zone of Chernobyl increases the risk of cancer at a moderate to high grade, connected also with the induction of complex DNA damage by radiation. Generally, our methodology has proven to be useful for assessing γ rays-induced complex DNA damage levels of the exposed population, in the case of a REI and for better understanding the long-term health effects of exposure of the population to IR.

Clustered DNA Damage Patterns after Proton Therapy Beam Irradiation Using Plasmid DNA

“…Linear Energy Transfer (LET)-oriented studies shows, in most cases, an increased amount of clustered damage with increasing LET, leading to increased DNA fragmentation [ 8 , 9 , 10 , 11 , 12 , 13 ]. Monte Carlo simulations and multiscale mathematical approaches also agree with these results and suggest that LET (or, more exactly, the ionization density) plays a major role in determining the biological effects [ 6 , 14 , 15 , 16 ]. Therefore, there is a great need for DNA damage biomarkers for a better understanding of the normal tissue damage in proton and particle therapy beams and a deeper understanding of the mechanisms leading to either cell death or other effects [ 17 ].…”

Evaluation of Radiological Effects on the Aptamers to Remove Ionic Radionuclides in the Liquid Radioactive Waste

“…Monte Carlo N-Particle transport code version 6 (MCNP6) [23] and Monte Carlo damage simulation (MCDS) [24][25][26] were used as the evaluation tools for the DNA damage in this study. MCNP6 was used to evaluate the secondary electron spectrum and the absorbed dose in a medium using photons from gamma-generating nuclides, and MCDS was used to calculate the DNA damage by using the secondary electron spectrum and the absorbed dose as inputs [27].…”

Radiation-induced DNA damage by proton, helium and carbon ions in human fibroblast cell: Geant4-DNA and MCDS-based study

“…The present study calculated yields of DNA damages in human fibroblast cell which is a diploid cell. The number of base pairs in typical human fibroblast cell is around 6.4 Gbp within a nucleus volume of ∼ 500 μm 3 (Sakata et al 2020, Kalospyros et al 2021). Thus, the base pair density (r bp ) = 1.28 × 10 −2 Gbp/μm 3 .…”