Abstract
Recent studies have showed that the sharp of the LET-RBE curves of biological effects was different, when using different ion species even if similar LET values. We also before reported that the sharp of LET-RBE curves of cell killing was different, when using different ion species such as carbon neon silicon and iron ions. This study, we investigated LET- and ion-species dependence on deletion pattern of exons in mutation induction at the hprt locus. Normal human skin fibroblasts were irradiated with carbon-, neon-, silicon- and iron- ion beams generated by Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS). The 6-thioguanine resistant colonies were isolated and extracted genomic DNA from the colonies. The mutation spectrum of the deletion pattern of exons was analyzed by multiplex polymerase chain reaction (PCR). The deletion pattern of exons was different in induced mutants among different ion species. Furthermore, the mutation spectrum in mutants induced by both carbon- and neon- ion beams showed LET dependent manner and was different when using different accelerated energies even if ion species were the same. These results suggested that the differences in the track structure of energy deposition with different ion species and energies could have an effect on mutation induction.
