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Irradiation field formation using an amplitude-modulation wobbling system for the compact carbon-therapy facilty
https://repo.qst.go.jp/records/68735
https://repo.qst.go.jp/records/6873541f061de-afd2-48b0-8f80-550d7901703f
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2006-10-24 | |||||
| タイトル | ||||||
| タイトル | Irradiation field formation using an amplitude-modulation wobbling system for the compact carbon-therapy facilty | |||||
| 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_c94f | |||||
| 資源タイプ | conference object | |||||
| 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 |
Yonai, Shunsuke
× Yonai, Shunsuke× Komori, Masataka× Kanematsu, Nobuyuki× Kanai, Tatsuaki× 米内 俊祐× 小森 雅孝× 兼松 伸幸× 金井 達明 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 1.Purpose We have studied compact facilities for the carbon therapy to popularize the radiotherapy. In these studies, the length of an irradiation port is required to downsize to half of that in HIMAC. However, the wobbler-scatterer system, which has used in HIMAC at present, cannot be applied directly to the purpose because the residual range shortens by thicker scatterers required for the short irradiation port. An amplitude-modulation wobbling system with a thin scatterer has been studied to overcome the problem. Especially, we have proposed the spiral wobbling method which produces circular irradiation fields up to 22 cm diameter using a fixed beam size of ~25 mm. We have also studied several amplitude-modulation wobbling methods such as multi-spiral wobbling and zigzag wobbling.(S. Yonai et al, PTCOG43) In this study, we compare spiral and zigzag wobbling methods through measurements and calculations to evaluate the optimum wobbling method. We also estimated that the method is satisfied the requirement. 2.Methods These methods are compared in the following aspects. 1) Relationship between the wobbling radius and the irradiation field, 2) Beam efficiency and 3) Time to make an irradiation field with an adequate flatness. These evaluations were mainly performed by calculation of the Gaussian-superposition, which had validated by measurements with a proto-type of the irradiation port in HIMAC. The proto-type system has the two orthogonally-wobbler magnets which are driven by independent power supplies with programmable waveforms. The maximum wobbling radii are ~165 and ~140 mm at isocenter for 290 and 400 MeV/u carbon beam, respectively. A dynamic intensity control system with RF-knockout extraction (S. Sato et al, EPAC'06) was used as a flattening filter of the beam to evaluate aspect 3). 3. Results These wobbling methods are almost the same performance. Since the zigzag wobbling method has an advantage from the point of view of a power supply, the method is the optimum wobbling one. Moreover, we found that the regulated zigzag wobbling method can makes it possible to provide the irradiation field of 22 cm diameter with the extension of the path length which is permissible in the present design. 4. Conclusions Amplitude-modulation wobbling system has advantages of its simple design and high beam efficiency compared with the conventional wobbler-scatterer method. The regulated zigzag wobbling method is the optimum in the system. We have already obtained the properties of the regulated zigzag wobbling method, and the proto-type system included beam monitors etc. is under improvement to obtain the stability for the popularization of the carbon therapy in Japan. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | PTCOG45 | |||||
| 発表年月日 | ||||||
| 日付 | 2006-10-11 | |||||
| 日付タイプ | Issued | |||||
