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SU-E-T-26: A Study On the Influence of Photonuclear Reactions On the Biological Effectiveness of Therapeutic High Energy X-Ray Beam
https://repo.qst.go.jp/records/54555
https://repo.qst.go.jp/records/54555fc9a5892-173f-4743-a403-68343cb80861
| Item type | 会議発表論文 / Conference Paper(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2015-06-29 | |||||
| タイトル | ||||||
| タイトル | SU-E-T-26: A Study On the Influence of Photonuclear Reactions On the Biological Effectiveness of Therapeutic High Energy X-Ray Beam | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_5794 | |||||
| 資源タイプ | conference paper | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Wakita, Akihisa
× Wakita, Akihisa× Matsufuji, Naruhiro× Kohno, Toshiyuki× Kodaira, Satoshi× al., et× 脇田 明尚× 松藤 成弘× 河野 俊之× 小平 聡 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Purpose: Photons from a modern high-energy therapeutic linear accelerator used in X-ray radiotherapy causes photonuclear reactions in an accelerator or patient's body. The aim of this study is to evaluate the biological effectiveness including these particles by Microdosimetric Kinetic Model (MKM) based on microdosimetry. Methods: A linear accelerator operating at 15 MV was used. CR-39 was used to obtain LET spectra of secondary ions selectively, as CR-39 is regarded insensitive to photons. CR-39 was put on the central axis of the X-ray beam at depths of 0, 5 and 10 cm in plastic phantom at a source to detector distance of 100 cm. Pits formed by the traversal of ions were etched then analyzed to obtain restricted LET distribution. Frequency-mean and dose-mean lineal energy was evaluated from the relationship between the restricted LET and the lineal energy required to evaluate the biological effectiveness by MKM. The relationship was calculated by Monte Carlo simulations with GEANT4. Results: Restricted LET distributions of secondary particles showed broad distributions that decreases exponentially with increasing LET. Frequency-mean and dose-mean lineal energy were determined uniquely within the scope of the energies of secondary particles generated from photons of 15 MeV. The frequency-mean lineal energies at the depth of 0, 5 and 10 cm were 15.1, 16.0 and 19.7 keV/μm respectively, and the dose-mean lineal energies were 18.6, 20.5 and 19.6 keV/μm, respectively. RBE of secondary particles for HSG cell evaluated by MKM was about 2.0 at all depths, and RBE of all particles including photons was evaluated 1.0. Conclusion: We investigated the biological effectiveness of secondary particles by photonuclear reactions. The method to evaluate RBE by MKM was established with measurements and simulations. However, the influence of these secondary ions on RBE was found negligible in the entire biological effectiveness of the high-energy X-ray. |
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| 書誌情報 |
Medical Physics 発行日 2015-02 |
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| 出版者 | ||||||
| 出版者 | American Association of Physicists in Medicine | |||||
| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 0094-2405 | |||||
| DOI | ||||||
| 識別子タイプ | DOI | |||||
| 関連識別子 | http://dx.doi.org/10.1118/1.4888356 | |||||
