• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2421-2427
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• 2024

In this research, the Omicron variant of the SARS-CoV-2 virus was simulated and exposed to electron radiation with up to 20 keV energy. Absorbed energy was measured for spike protein, nucleocapsid protein, and envelope of the virus. Simulations were performed by Geant4-DNA in a water environment at temperature of 20 ℃ and pressure of 1 atm. Since the viral RNA is kept inside the nucleocapsid protein, damage to this area could destroy the viral RNA strand and create an inactive virus. Our findings showed that electron beams with an energy of 2.5 keV could cause a maximum absorption dose and consequently maximum damage to the nucleocapsid and effectively be used for inactivation virus.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.9 no.2
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• pp.75-80
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• 2023

Modelling the damage to DNA molecules by ionizing radiation plays a crucial part in predicting the biological effects of any form of radiation therapy, but the creation of accurate damage models remains scientifically challenging. This study evaluated the frequency and severity of DNA strand breaks caused by direct and indirect radiation effects using the Geant4 DNA simulation toolkit. The DNA itself was represented as a continuous fractal Hilbert curve with a total length of approximately 6.4 Gbp, consisting of straight and twisted chromatin sections placed inside a simplified model of a human fibroblast cell. Using At-211 and Ac-225, both alpha-emitting radionuclides employed under assumption of radiopharmaceutical treatment, the results were compared to those from external irradiation with 1.5 MeV gamma rays. For each Gy of absorbed dose, the strand break yields were 103 ± 10 SSBs/Gbp and 15 ± 4 DSBs/Gbp for At-211, 96 ± 10 SSBs/Gbp and 15 ± 4 DSBs/Gbp for Ac-225, as well as 198 ± 14 SSBs/Gbp and 7 ± 3 DSBs/Gbp for the gamma rays. Thus, the radionuclides exhibited more than double the incidence of DSBs at the expense of SSBs compared to the gamma radiation. By demonstrating the feasibility of adapting the Geant4 DNA toolkit for in silico studies of the radiobiological effects of therapeutic radiopharmaceuticals at the DNA level, this is the first step towards the development of a comprehensive simulation model for determining the relative biological effectiveness of radiopharmaceuticals.