Radiobiological study on hypofractionated high-precision radiotherapy

2016 Fiscal Year Final Research Report

• Project/Area Number: 26461887
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: Osaka University
• Principal Investigator: Seo Yuji 大阪大学, 医学系研究科, 助教 (00302000)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 高精度放射線治療 / DNA2本鎖切断修復 / 相同組換え修復 / 非相同末端接合

Outline of Final Research Achievements

We investigated cellular responses to a high-dose-per-fraction radiotherapy compared with a conventionally fractionated radiotherapy. Based on an analysis using biomathematical models, underlying mechanisms of radiosensitizing effects were classified into three factors: 1) Increase of initial DNA damages, 2) Inhibition of DNA double-strand break (DNA-DSB) repairs, and 3) Increased chromosomal translocations mediated by non-homologous end joining. Since a probability of chromosomal translocations is proportional to a square dose, the third mechanism enhanced radiosensitivity in the high dose range to a greater extent than the second mechanism. Through the third mechanism, the altered selection of DNA-DSB repair pathways impacted on radiosensitivity without any changes in the total amount of the initial DNA damage and its repair. The pathway choice of the DNA-DSB repair can be a potential molecular target for hypofractionated high-precision radiotherapy.

Free Research Field

放射線治療生物学