Development of semiconductor detector for radiation quality measurement of therapeutic carbon beams

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K15541
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Gunma University
• Principal Investigator: Matsumura Akihiko 群馬大学, 重粒子線医学推進機構, 助教 (90600453)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 半導体検出器 / 重粒子線 / 線質

Outline of Final Research Achievements

In this study, we developed a semiconductor detector that can measure both the dose and radiation quality of carbon beams used in cancer therapy and evaluated the carbon beam fields used in clinical practice.
Response to carbon beams was investigated using an existing semiconductor detector, noise sources were identified, and improvements were made to the data acquisition system to create a system capable of measuring a wide range of radiation energies, from primary carbons to secondary fragments. Using this system, we have measured the radial radiation quality variation of the therapeutic carbon pencil beam, the effect of irradiation field size on radiation quality in the broad beam method, and investigated the variation of dose-averaged energy transfer to evaluate the biological effects. The system constructed in this study will further advance our understanding of the therapeutic carbon beam field.

Free Research Field

医学物理

Academic Significance and Societal Importance of the Research Achievements

がん治療で用いられる炭素線は生物学的効果が大きく、X線や陽子線では効きにくかった種類のがんに対しても効果が期待できる。一方で、その効果を推定するエネルギー付与の分布（線質）は照射範囲内で均一ではなく、複雑に変化している。
本研究で構築した有感領域の小さい半導体検出器は、複雑に変化する炭素線場の線質評価に優れており、今後様々な条件下での測定に応用することによって、治療用炭素線場の生物学的効果の理解が一層進むと考えられる。