Abstract
Heavy ion particles are utilized for cancer therapy, because they show the higher LET and the typical Bragg peak, both lead to kill targeted cancer cells efficiently. However, we have known little about intracellular DNA damage induced by heavy ion particles. In this study, we estimated the number of DNA damage including strand breaks and/or oxidative base lesions, and evaluated their localization using pDEL19 and lambda DNA as target substrates. These DNA were irradiated by g-rays (0.2 keV/µm), carbon (13 keV/µm) and iron ions (200 keV/µm), and analyzed by gel electrophoreses and aldehyde reactive probe method. The result showed that total damage per dose were decreased with increase in LET. Even clustered damage per dose also were decreased with increase in LET. It suggests that quality of clustered damage is more important to elicit the biological effect than quantity of that. Quality of clustered damage contains the number, the species and the disposition of respective lesions in each clustered damage. Therefore, we also report here our examined procedures to evaluate the quality of clustered damage.
