2023 Fiscal Year Final Research Report
Real-time measurement of BNCT treatment effectiveness by narrow angle Compton gamma-ray detection and anticoincidence method
| Project/Area Number |
20K21164
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 31:Nuclear engineering, earth resources engineering, energy engineering, and related fields
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| Research Institution | Osaka Metropolitan University (2022-2023)
Osaka Prefecture University (2020-2021) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小嶋 崇夫 大阪公立大学, 工学(系)研究科(研究院), 助教 (70360047)
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| Project Period (FY) |
2020-07-30 – 2024-03-31
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| Keywords | BNCT / gamma-ray detector / anticoincidence / Compton |
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| Outline of Final Research Achievements |
A new method for precise measurement of gamma rays emitted from a patient's body has been proposed to evaluate the efficacy of boron neutron capture therapy (BNCT), an effective treatment for head and neck cancer, and its effectiveness has been demonstrated by simulation calculations and experiments. In order to effectively reduce the signal due to Compton scattering of hydrogen-captured gamma rays, only gamma rays scattered at small angles are selectively measured using a secondary detector in a later stage, and anti-coincidence method was applied.
Calculations showed that placing four 5 cm thick cesium iodide scintillation detectors in the rear stage at an angle of about 20 degrees showed 80 % decrease of Compton continuum counts . In the experiment, a special plate-shaped detector was fabricated by the research group and a preliminary verification of the proposed method was conducted using a standard gamma-ray source, and it was found that a 4% improvement could be achieved.
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| Free Research Field |
放射線計測 放射線物理
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| Academic Significance and Societal Importance of the Research Achievements |
人体からの478keVガンマ線の計測は多くの研究者が行っているが、妨害因子となる他のガンマ線の除去は通常困難であり、測定感度が低いことが問題となっている。これを向上させるには非同時計数法が有効であるが、従来と異なりピーク判別だけに絞ることで特定散乱角度を持つコンプトン散乱線だけを信号処理の対象とした点に新規性があり、その有効性がシミュレーション計算と予備的実験の両方で確認できた。BNCTにおいて照射中の治療評価法の確立するための新しい検出器体系を提案した意義は大きい。本システムを完成するには特殊形状の結晶などが必要であるが、今後のシステムの確立のための有効な知見が成果として得られた。
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