Abstract
This oral discusses the data obtained with the increased or decreased tendencies to yields of DNA double strand breaks (DSB) produced by the high linear energy transfer (LET) radiations in order to obtain RBE values.
Our oral focused the indirect action (e.g., OH radicals) as one of reasons relationship to the induction of DSB. Yokoya et al., have reported the induction of DSB induced by the direct action of helium ion irradiation of hydrated plasmid DNA. Induction of DSB increased with increasing LET, increased ionization density of particle beams. Terato et al., have also reported that the plasmid DNA in buffer were irradiated with carbon and iron ions. Effects of these radiations are affected by direct and indirect actions. However, induction of DSB decreased with increasing LET. In the case of experiment system, radiation action of gamma rays and particle beams involve two actions: Direct and indirect actions. Thus, indirect action of radiations may play an important role in the induction of DSB as a function of the LET.
