Exploring the biological response dynamics after proton beam irradiation through time-lapse observation: a study towards the development of optimal fractionation methods

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K16830
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Nagoya City University
• Principal Investigator: Nakajima Koichiro 名古屋市立大学, 医薬学総合研究院(医学), 研究員 (50866176)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 陽子線治療 / FLASH照射 / ショウジョウバエ

Outline of Final Research Achievements

In the initial plan of this study, experiments on cultured cells and Drosophila were intended to be conducted concurrently. However, priority was given to ultra-high dose rate proton irradiation (FLASH irradiation) experiments on Drosophila. Experiments comparing normal dose rate irradiation and FLASH irradiation were conducted using wild-type Drosophila third instar larvae and virgin female adults. Post-irradiation gene expression analysis revealed differential gene expression levels due to varying dose rates in specific genes. In contrast, in the irradiation experiments on virgin female adults, no significant differences were observed in the pupation and eclosion rates of the first generation offspring (F1), nor in their activity levels per unit time post-eclosion.

Free Research Field

放射線腫瘍学

Academic Significance and Societal Importance of the Research Achievements

陽子線治療は低侵襲ながん治療の選択肢として重要な役割を果たしている。「超高線量率照射=FLASH照射」は、未だ生物学的機序において不明な点が多いが、臨床応用されれば、さらなる低侵襲化を可能とする画期的な照射法として期待されている。本研究の成果は、FLASH照射の生物学的基礎研究の普及に向けた実験モデルの構築に寄与するものであり、ショウジョウバエにおいても線量率の違いにより反応に差が出る可能性が示唆されたことは、今後に期待の持てる結果であった。