Abstract
We have estimated the DNA damage spectrum by track structure simulation method. The simulation result shows that the increase of the complexity of initial DNA damage and cell lethality show partially similar trend in their LET dependence. The goal of our study is to elucidate and modeling the relationship between initial DNA damage and radiation-induced cellular response by using the calculated DNA damage spectrum. For this purpose, in addition to the detail of the clustered DNA damage in nanometer scale, the spatial distribution of the damage in larger scale should be considered. In this presentation, The DNA damage spectrum calculated for gamma-rays, X-rays and heavy ions will be shown. The calculation was performed using the simulation system which had been improved in DNA model and damage spectrum analysis method. Next, the spatial distribution of each type of DNA damage around the radiation track will be shown. The simulated DNA damage spectrum and the spatial distribution such as the distance between two clustered DNA damages in chromosome domain in cell nucleus model was discussed in comparison with the yield of lethal damage estimated from the experimentally obtained survival curves.
