@misc{oai:repo.qst.go.jp:00076617,
 author = {Nakanishi, Ikuo and Shoji, Yoshimi and Ueno, Megumi and Emiko, Sekine-Suzuki and Matsuoka, Yuta and Shimokawa, Takashi and Ken-ichi, Yamada and Ken-ichiro, Matsumoto and Nakanishi, Ikuo and Shoji, Yoshimi and Ueno, Megumi and Sekine, Emiko and Shimokawa, Takashi and Matsumoto, Kenichiro},
 month = {Aug},
 note = {Carbon-ion (C-ion) beams are known to exhibit a sharp maximum of the energy deposition, called as a Bragg peak, at a certain penetration depth.  Thus, the cancer cells are precisely killed by adjusting the Bragg peak to a tumor.  However, the dose in the plateau region of the C-ion beams before the Bragg peak is not necessarily zero.  Thus, the quantitative evaluation of changes in the redox state induced by the plateau C-ion beams is considerable importance to eliminate the adverse effects of radiation therapy on normal tissues adjacent to the tumor.  We have recently demonstrated that isopropyl myristate (IPM), one of lipid molecules, is more susceptible to the plateau C-ion beams than to X-rays using 2,2-diphenyl-1-picrylhydrazyl radical used as a redox probe.  In this study, the effect of the plateau C-ion beams on lipid molecules was further investigated by 2,2,6-trimethyl-4-(4-nitrobenzo[1,2,5]oxadiazol-7-ylamino)-6-pentylpiperidine-1-oxyl (NBD-Pen), a highly selective fluorescence probe for lipid radicals with high sensitivity.  NBD-Pen reacts with the lipid radicals generated by the oxidation of lipid molecules to form highly fluorescent radical adducts.  IPM solutions of NBD-Pen (5.0 µM) were irradiated by the plateau C-ion beams (290 MeV, 13 keV/µm) using the Heavy Ion Medical Accelerator in Chiba (HIMAC) at room temperature.  An increase in fluorescence intensity at 509 nm was observed for the IPM solutions of NBD-Pen after the C-ion irradiation (5, 10, 15, 20, and 30 Gy) on a Shimadzu RF-5300PC spectrofluorophotometer.  This indicates that radical species were generated by the C-ion irradiation to IPM.  The fluorescence intensity increased with an increase in the radiation dose and reached its maximum value around at 10 Gy.  The effect of the plateau C-ion beams on the lipid oxidation will be discussed as compared to that of X-rays based on the results obtained in this study., 16th International Congress of Radiation Research (ICRR 2019)},
 title = {Detection of Radical Species after Plateau Carbon-Ion Irradiation to Lipid Molecules},
 year = {2019}
}