@misc{oai:repo.qst.go.jp:00071540,
 author = {Nakamura, Mizuki and Shibata, Sayaka and Ozawa, Yoshikazu and Ueno, Megumi and Matsumoto, Ken-ichiro and Yamada, Ken-ichi and Kamada, Tadashi and Aoki, Ichio and 中村 美月 and 柴田 さやか and 尾澤 芳和 and 上野 恵美 and 松本 謙一郎 and 鎌田 正 and 青木 伊知男},
 month = {Nov},
 note = {Theranostics is being highlighted in fields of radiotherapy. Theranostics is a combination term of diagnostics and therapeutics, provides optimization of individualized medicine status based on the pathophysiological conditions. For cancer radiotherapy, theranostics is important for selection of efficient therapy and protection of normal tissues. Optimum timing of using radio protector or sensitizer with sufficient dose was required for radiotherapy irradiating individual tissues. Time course of brain tissue redox status of normal mouse after X-ray and carbon-ion beam irradiation was studied. 
Heads of mice were irradiated by 8 Gy X-ray or 16 Gy carbon-ion beam. The bragg peak was planned to hit cortex area. The mice were conducted to take redox imaging 1, 2, 4, 8 days later from irradiation by 7 T MRI using T1 weighted gradient echo. The decay rate of nitroxyl induced signal was analyzed. Non-irradiation mice were also taken redox imaging. This study used nitroxyl contrast agent, MC-PROXYL (3-Methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy) all experiments.
MC-PROXYL was immediately distributed in entire brain after injection and T1-weighted signal enhancement increased both groups of irradiation and non-irradiation. It showed 2-phase decay curve, which has initial fast phase and later slow phase. Decay rate of fast phase (k) was not so different between cortex area and medulla area; however ventricle area showed slight slower decay rate k. Decay rate k was slightly faster in non-irradiated group than irradiated group. In addition, decay rate k was faster in entire brain 2 days after irradiation compare to 1 day after irradiation. No clear difference was observed between X-ray and carbon-ion beam in this case.
The result suggested that redox status was changed by irradiation because decay curve of nitroxyl-induced T1 signal had a difference between irradiated and non-irradiated groups. We will plan additional analysis to consider changing redox status in tissues by irradiation X-ray and carbon-ion beam to mice., APES-IES-SEST 2014 (Joint Conference of 9th Asia-Pacific EPR/ESR Society Symposium, 1st International EPR (ESR) Society Symposium, and 53rd SEST Annual Meeting)},
 title = {Time Course Analysis of Radiation Induced Alteration of Tissue Redox Status Using MR Redox Imaging},
 year = {2014}
}