2023-01-31T12:03:46Zhttps://repo.qst.go.jp/?action=repository_oaipmhoai:repo.qst.go.jp:000461792019-02-28T07:32:27Z00001
ANALYSIS OF CELL-SURVIVAL FRACTIONS FOR HEAVY-ION IRRADIATIONS BASED ON MICRODOSIMETRIC KINETIC MODEL IMPLEMENTED IN THE PARTICLE AND HEAVY ION TRANSPORT CODE SYSTEMenghttp://id.nii.ac.jp/1657/00046166/Journal ArticleSato, TatsuhikoWatanabe, RitsukoKase, YukiTsuruoka, ChizuruSuzuki, MasaoFurusawa, YoshiyaNiita, KojiIt is considered that the linear energy transfer (LET) may not be the ideal index for expressing the relative biological effective- ness (RBE) of cell killing for heavy-ion irradiation, as the ion-species dependencies have clearly been observed in the relation between LET and RBE derived from cell-survival fraction data. The previously measured survival fractions of four cell lines irra- diated by various ion species, employing the saturation-corrected dose-mean lineal energy, y*, instead of LET as the index of the RBE were therefore re-analysed. In the analysis, the initial slopes of the survival fractions, the so-called a-parameter in the linear-quadratic model, were plotted as a function of y*, which was calculated by the microdosimetric kinetic (MK) model implemented in the Particle and Heavy Ion Transport code System. It was found from the analysis that the ion-species depen- dencies observed in the relations between a and LET disappeared from those between a and y*, and their relations can be well reproduced by a simple equation derived from the MK model. These results clearly indicate the suitability of y* to be used in the estimation of the RBE of cell killing for heavy-ion irradiations, which is of great importance in the treatment planning of charged-particle therapy.Radiation Protection Dosimetry1432/44914962010-120144-842010.1093/rpd/ncq484none2019-02-14