[1C01-07] Environmental Radiation

10:00 AM - 10:15 AM JST(1:00 AM - 1:15 AM UTC)

[1C01] Study on the new mathematical model considering DNA damage repair in radiation biology.

*Kazuya Nakashima¹, Youichirou Matuo¹, Kikuo Shimizu², Yoshinobu Izumi² (1. Graduate School of engineering, Univ. of Fukui, 2. Research Institute of Nuclear Engineering, Univ. of Fukui)

Keywords:

Mathematical model,Radiation biology,DNA damage repair

In order to express low-dose responses such as radiation hypersensitivity and dose-rate effects, new mathematical models (r model and r' model) were constructed to represent survival rates considering DNA damage repair by a combination of cellular response and kinetic theory. The coefficient α (/Gy) for the efficiency of DNA damage and the rate constant r (/min) for DNA damage repair were determined from the survival rates of the RAD⁺ and rad52 strains of budding yeast when exposed to soft X-rays. The boundary value of the effect of repair r', T(min), and the initial value β were determined from the analysis of the expression folds of the repair gene RAD54 in RAD⁺ strains. Least-squares fitting using the r model was performed for survival rates. The results show that the rad52 strain has less effect on repair compared to the RAD⁺ strain. The expression dose analysis defined T = 60 min and the initial value β = 1.4. The coefficient of determination R² for the survival of RAD⁺ strains show r model: R²=0.88 and r' model: R²=0.92. The r’ model is shown to be more accurate for survival rates.