Comparative analysis between BNCT and X-ray for radiation-induced late effect in normal muscle and bone

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K17230
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Gifu University
• Principal Investigator: Iwasaki Ryota 岐阜大学, 応用生物科学部, 助教 (20782139)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ホウ素中性子捕捉療法 / CBE factor / 骨強度 / 線維化 / 晩発性障害 / BPA

Outline of Final Research Achievements

In normal muscle, experiments were conducted to make a model of radiation-induced fibrosis (RIF). 75 Gy/3 Fr X-rays were irradiated to the right hindlimbs of two strains of mice, and RIF was confirmed after 12 weeks for C3H/He and 8 weeks for C57BL/6 by Masson trichrome staining. Western blot analysis of fibronectin and TGF-β expression showed increased expression earlier in C57BL/6 than in C3H/He.
In normal tibia, the boron compound BPA localized to the growth plate, trabecular bone, bone marrow, and periosteum/endosteum and maintained its concentration until 120 minutes after BPA administration. The CBE value of 2.34 was calculated as the conversion coefficient to X-ray equivalent dose when the biological endpoint was the decrease in bone strength after 12 weeks of X-irradiation and BNCT.

Free Research Field

放射線生物学

Academic Significance and Societal Importance of the Research Achievements

本研究で確立したRIFモデルマウスは、RIF発症機序の解明に寄与するとともに、今後の中性子線照射やBNCTを行う上での基礎データを提供するものである。
骨においてはBNCTでも骨強度の低下が起こりうるという知見が得られたが、求めたCBE値を処方線量に組み込み、さらなる照射実験により正常骨に与える晩期的影響を評価することで、将来的に適正な線量を勘案したBNCTの実施が可能となるであろう。