Evaluation of beam qualities and absolute doses using a calorimeter in particle therapy fields

2016 Fiscal Year Final Research Report

• Project/Area Number: 26860406
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Medical Physics and Radiological Technology
• Research Institution: National Institutes for Quantum and Radiological Science and Technology
• Principal Investigator: SAKAMA MAKOTO 国立研究開発法人量子科学技術研究開発機構, 放射線医学総合研究所 病院, 主任研究員(定常) (80455386)
• Research Collaborator: KASE Yuki 静岡県立静岡がんセンター(研究所), 陽子線治療研究部, 主任研究員 (70455385)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 重粒子線治療 / 線量測定 / カロリメータ / ロバストネス / 不確かさ

Outline of Final Research Achievements

In heavy ion beam therapy, the absorbed dose is measured using the ionization chambers, and the absolute value of the dose to be irradiated is obtained. Physical quantities such as w value, stopping power ratio, and perturbation correction factor are necessary to determine the absorbed dose using the ionization chambers, but these physical quantities are not accurate and the uncertainty of the absorbed dose becomes large. Therefore, using the calorimeter capable of measuring absolute doses with high precision, we measured the absorbed dose in heavy ion beams under the treatment conditions, and advanced the dose measurement. According to the current international dosimetry protocol, measured absorbed doses were underestimated by about 3% than those obtained using a calorimeter for heavy ion beams. Based on these results, we developed a fast robustness evaluation method to the treatment plan considering the correlation of various errors under the treatment conditions.

Free Research Field

放射線科学