Development of neutron energy distribution evaluation technique for accelerator-based BNCT

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K21679
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Quantum beam science; Medical Physics and Radiological Technology
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Masuda Akihiko 国立研究開発法人産業技術総合研究所, 計量標準総合センター, 主任研究員 (70549899)
• Research Collaborator: MATSUMOTO Tetsuro ; HARANO Hideki ; KUMADA Hiroaki ; TAKADA Kenta
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 中性子 / 放射線計測 / ホウ素中性子捕捉療法 / BNCT / 大強度中性子 / ボナー球 / シンチレーター / 放射線治療

Outline of Final Research Achievements

Neutron energy distribution measurement technique for accelerator-based boron neutron capture therapy (BNCT) was developed in this project. Firstly, neutron spectral fluence of weak beams of an accelerator-based BNCT facility was measured using a conventional Bonner sphere spectrometer (BSS) based on a He-3 proportional counter and applicability of the Bonner unfolding method for BNCT neutrons was demonstrated. Thereafter, a new BSS using lithium-glass scintillators was developed to measure the therapy-level intense neutron beam directly. Gamma-ray correction method using a pair of the Li-6- and Li-7-glass scintillators and the current integration measurement of PMTs' output were employed. After characteristic evaluation, the new BSS was used to measure the intense neutron beams at the accelerator-based BNCT facility.

Free Research Field

放射線計測

Academic Significance and Societal Importance of the Research Achievements

加速器BNCTでは、小型加速器による大強度中性子発生技術が急速に進展した一方で、生成した中性子ビームを実験的に精密測定する技術の開発が強く望まれていた。本研究では、BNCT用加速器中性子源の実機に対する中性子スペクトル測定に成功し手法の有効性を実証するとともに、治療レベルの大強度中性子のエネルギー分布を直接測定できる検出器を開発した。これらの過程で、BNCT用中性子の特性に応じた測定ノウハウも蓄積された。これらを活用・発展させることで、BNCT治療実績の向上に貢献できるだけでなく、大強度中性子の測定技術そのものの発展にも寄与できると考えている。