Development of delivery dose monitoring system for photon beam radiotherapy

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K16484
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Radiation science
• Research Institution: Keio University
• Principal Investigator: Hanada Takashi 慶應義塾大学, 医学部(信濃町), 講師 (30571054)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 放射線治療 / 放射線計測 / 消滅γ線

Outline of Final Research Achievements

In this study, a detector system consisting of crystal scintillator was designed and assessment of annihilation radiation signal emerged from prompt pair production induced by therapeutic high energy x-ray beams used in medical linear accelerator was performed. It was successfully operated to confirm the entire radiation signals by real-time measurements of counting rates, which were found to be proportional to the intensity of the photon beam. On the other hand, measurements disclosed a severe background that does not solely stem from scattered primary photons but from radiation directly emitted from the treatment head, result in no success in identifying annihilation radiation. However, by improving the techniques, the proposed method has potential that could be used for the real-time monitoring of the irradiation dose and field during the beam irradiation.

Free Research Field

医学物理

Academic Significance and Societal Importance of the Research Achievements

外部照射による放射線治療では、治療ビーム照射中に標的領域に計画した線量が確実に投与されている事象を確認する手段が未だ存在せず、現在でも投与線量の過剰・過少照射事故が起きている現状がある。本研究計画で推進した計測技術は、成功すれば安全な線量投与が担保された次世代型の治療支援システムの基盤構築の一助となる。そして、外部放射線治療技術を抜本的に転換し、治療ビーム照射中にフィードバックをかけることで投与線量の精度向上や事故の未然防止等が可能になる道が開かれる。