Elucidation of biological effects of proton therapy - comparison with X rays

2018 Fiscal Year Annual Research Report

• Project/Area Number: 15K10006
• Research Institution: Nagoya City University
• Principal Investigator: 芝本 雄太 名古屋市立大学, 大学院医学研究科, 教授 (20144719)
• Co-Investigator(Kenkyū-buntansha): 村井 太郎 名古屋市立大学, 大学院医学研究科, 助教 (00747602) ; 荻野 浩幸 名古屋市立大学, 大学院医学研究科, 高度医療教育研究センター教授 (60315885) ; 岩田 宏満 名古屋市立大学, 大学院医学研究科, 研究員 (40611588)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 陽子線治療 / 放射線生物学 / SLDR / PLDR

Outline of Annual Research Achievements

To clarify the biological response of tumor cells to proton beam irradiation, the sublethal damage recovery (SLDR) and potentially lethal damage recovery (PLDR) induced after proton beam irradiation at the center of a 10-cm spread-out Bragg peak (SOBP) were compared with those seen after X-ray irradiation. Cell survival was determined by a colony assay using EMT6 and HSG cells. First, two doses of 4 Gy/GyE were given at an interfraction interval of 0-6 h. Second, five fractions of 1.6 Gy/GyE were administered at interfraction intervals of 0-5 min. Third, a delayed-plating assay involving cells in plateau-phase cultures was conducted. The cells were plated in plastic dishes immediately or 2-24 h after being irradiated with 8 Gy/GyE of X-rays or proton beams. Furthermore, we investigated the degree of protection from the effects of X-rays or proton beams afforded by the radical scavenger dimethyl sulfoxide to estimate the contribution of the indirect effect of radiation. In both the first and second experiments, SLDR was more suppressed after proton beam irradiation than after X-ray irradiation. In the third experiment, there was no difference in PLDR between the proton beam and X-ray irradiation conditions. The degree of protection tended to be higher after X-ray irradiation than after proton beam irradiation. In conclusion, compared with that seen after X-ray irradiation, SLDR might take place to a lesser extent after proton beam irradiation at the center of a 10-cm SOBP, while the extent of PLDR does not differ between these two conditions.

Research Products

• [Journal Article] Effect of a Device-Free Compressed Shell Fixation Method on Hepatic Respiratory Movement: Analysis for Respiratory Amplitude of the Liver and Internal Motions of a Fiducial Marker (2019)
  • Author(s): Hashimoto S, Katsurada M, Muramatsu R, Asai K, Tanaka K, Hayashi K, Kibe Y, Nakajima K, Hattori Y, Iwata H, Mizoe JE, Ogino H, Shibamoto Y.
  • Journal Title: Practical Radiation Oncology Volume: 9 Pages: e149-155
  • DOI: 10.1016/j.prro.2018.10.001
  • Peer Reviewed
• [Journal Article] Recovery from sublet damage and potentially lethal damage: proton beam irradiation vs. X-ray irradiation (2018)
  • Author(s): Hashimoto S, Sugie C, Iwata H, Ogino H, Omachi C, Yasui K, Mizoe JE, Shibamoto Y
  • Journal Title: Strahlenqherpie und Onkologie Volume: 194 Pages: 345-351
  • DOI: 10.1007/s00066-017-1223-9
  • Peer Reviewed
• [Presentation] Effects of proton beams and X rays on the cell cycle of fluorescent ubiquitination-based cell cycle indicator (Fucci)-expressing cells (2018)
  • Author(s): Hiromitsu Iwata, Yuta Shibamoto 他
  • Organizer: 2018 Annual Meeting of the American Society for Radiation Oncology
  • Int'l Joint Research
• [Presentation] Drosophila Melanogaster as a Model Organism to Study Biological Effects of Proton Radiation (2018)
  • Author(s): Koichiro Nakajima, Yuta Shibamoto 他
  • Organizer: 2018 Annula Meeting of the Particle Therapy Cooperative Group
  • Int'l Joint Research