カワムラ　ヒデマサ   KAWAMURA Hidemasa   河村　英将    所属   埼玉医科大学  医学部 総合医療センター　放射線科(画像診断・核医学科、放射線腫瘍科)    職種   教授
論文種別	学術雑誌(原著)
言語種別	英語
査読の有無	査読あり
表題	Evaluation of therapeutic gain for fractionated carbon-ion radiotherapy using the tumor growth delay and crypt survival assays
掲載誌名	正式名：Radiotherapy and Oncology ISSNコード：1879-0887/1879-0887
出版社	Elsevier Ireland Ltd
巻・号・頁	117(2),351-357頁
著者・共著者	Yukari Yoshida,Koichi Ando,Ken Ando,Kazutoshi Murata,Yuya Yoshimoto,Atsushi Musha,Nobuteru Kubo,Hidemasa Kawamura,Sachiko Koike,Akiko Uzawa,Takeo Takahashi,Tatsuya Ohno,Takashi Nakano
発行年月	2015/11/01
概要	Background and purpose The aim of the study was to evaluate the therapeutic gain of carbon ion (C-ion) radiotherapy using a mouse model. Materials and methods Transplanted fibrosarcoma (NFSa) growing in C3H/He mice and murine small intestine were irradiated with 290 MeV/nucleon C-ion beams (C-ions) in 1-12 fractions separated by 4 h. The cell killing efficiencies of C-ions were measured using jejunum crypt survival and tumor growth delay (TGD) assays. Results The equieffect dose for crypt survival and TGD increased with increasing number of fractions after X-rays and 20 keV/μm C-ions, whereas TGD after 77 keV/μm C-ions rather decreased. Crypts showed stronger LET-dependent increase in α terms than the tumor while β terms less depended on LET irrespective of tissues. Therapeutic gain factor, i.e., a ratio of tumor RBE over crypt RBE, of 77 keV/μm C-ions was more than unity at any doses while that of 20 keV/μm C-ions increased with an increase in dose per fraction. Conclusions These specific data imply that use of large dose per fraction would be suitable for C-ion radiotherapy irrespective of LET from the point of view of therapeutic gain, though small dose per fraction by high-LET radiation decreases total dose for tumor.
DOI	10.1016/j.radonc.2015.09.027
PMID	26454348