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アイテム
放射線治療線量定量のための電離線量の概念化
https://repo.qst.go.jp/records/2002046
https://repo.qst.go.jp/records/200204612723ab6-cee4-4df7-9a25-a39ed920234e
| アイテムタイプ | 会議発表用資料 / Presentation(1) | |||||||
|---|---|---|---|---|---|---|---|---|
| 公開日 | 2025-04-21 | |||||||
| タイトル | ||||||||
| タイトル | 放射線治療線量定量のための電離線量の概念化 | |||||||
| 言語 | ja | |||||||
| 言語 | ||||||||
| 言語 | jpn | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||||
| 資源タイプ | conference presentation | |||||||
| 著者 |
兼松 伸幸
× 兼松 伸幸
|
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| 抄録 | ||||||||
| 内容記述 | [Purpose] This study conceptualizes the ionization dose to water as the dose absorbed to water and expended exclusively on ionization, which is essential for cancer treatment, and formulates its dosimetric procedures for high-energy photon, electron, proton, and ion beams. It also aims to design optimal ionization chambers to reduce large dosimetric uncertainty for proton and ion beams. [Methods] Based on the international code of practice, the dosimetric procedure without the W-value correction was formulated for all beam types, and that without the stopping-power-ratio correction was formulated for proton and ion beams. For the latter, water-equivalent gas was considered for gas-sealed ionization chambers. Reference dosimetry was performed virtually for test beams. [Results] For photon and electron beams, the ionization dose was essentially equivalent to the absorbed dose. For proton and ion beams, dosimetric uncertainties were greatly reduced, especially with water-equivalent gas, to 0.7 % and 1.0 %, respectively. Nitrogen-based water-equivalent gas mixtures were designed with helium, methane, and ethane. Dosimetry with the helium mixture was prone and sensitive to leakage, while the methane and ethane mixtures were flammable. [Conclusion] The ionization dose with reduced beam quality corrections provides dose representations of improved accuracy and relevance to radiation therapy, particularly for proton and ion beams. [Remarks] This research was motivated by the recent activity of the Inter national Atomic Energy Agency to update the international code of practice for dosimetry Technical Report Series number 398, to which this presenter contributed in drafting and reviewing. The content of this presentation will eventually be published as an original paper in some scientific journal, and the publication status will be shown in the presentation for an interested audience. Future research will include development of prototype water-equivalent gas ionization chambers and their experimental evaluation mainly with ion beams at an ion-beam therapy facility, for which an application for Grants-in-Aid for Scientific Research to the Japan Society for the Promotion of Science has been under review at the time of this abstract submission. | |||||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||||
| 内容記述 | 第129回日本医学物理学会学術大会 | |||||||
| 発表年月日 | ||||||||
| 日付 | 2025-04-10 | |||||||
