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Systematic evaluation of four-dimensional hybrid depth scanning for carbon-ion lung therapy
https://repo.qst.go.jp/records/46690
https://repo.qst.go.jp/records/46690f3aa3e06-093f-444a-bb37-5c39d10c9e69
| Item type | 学術雑誌論文 / Journal Article(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2013-12-27 | |||||
| タイトル | ||||||
| タイトル | Systematic evaluation of four-dimensional hybrid depth scanning for carbon-ion lung therapy | |||||
| 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_6501 | |||||
| 資源タイプ | journal article | |||||
| 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 |
Mori, Shinichiro
× Mori, Shinichiro× Furukawa, Takuji× Inaniwa, Taku× Marius, Zenklusen Silvan× Nakao, Minoru× Shirai, Toshiyuki× Noda, Kouji× 森 慎一郎× 古川 卓司× 稲庭 拓× Ｚｅｎｋｌｕｓｅｎ Ｓｉｌｖａｎ Ｍａｒｉｕｓ× 中尾 稔× 白井 敏之× 野田 耕司 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | PURPOSE: Irradiation of a moving target with a scanning beam requires a comprehensive understanding of organ motion as well as a robust dose error mitigation technique. The authors studied the effects of intrafractional respiratory motion for carbon-ion pencil beam scanning with phase-controlled rescanning on dose distributions for lung tumors. To address density variations, they used 4DCT data. METHODS: Dose distributions for various rescanning methods, such as simple layer rescanning (LR), volumetric rescanning, and phase-controlled rescanning (PCR), were calculated for a lung phantom and a lung patient studies. To ensure realism, they set the scanning parameters such as scanning velocity and energy variation time to be similar to those used at our institution. Evaluation metrics were determined with regard to clinical relevance, and consisted of (i) phase-controlled rescanning, (ii) sweep direction, (iii) target motion (direction and amplitude), (iv) respiratory cycle, and (v) prescribed dose. Spot weight maps were calculated by using a beam field-specific target volume, which takes account of range variations for respective respiratory phases. To emphasize the impact of intrafractional motion on the dose distribution, respiratory gating was not used. The accumulated dose was calculated by applying a B-spline-based deformable image registration, and the results for phase-controlled layered rescanning (PCRL) and phase-controlled volumetric rescanning (PCRV) were compared. RESULTS: For the phantom study, simple LR was unable to improve the dose distributions for an increased number of rescannings. The phase-controlled technique without rescanning (1×PCRL and 1×PCRV) degraded dose conformity significantly due to a reduced scan velocity. In contrast, 4×PCRL or more significantly and consistently improved dose distribution. PCRV showed interference effects, but in general also improved dose homogeneity with higher numbers of rescannings. Dose distributions with single PCRL∕PCRV with a sweep direction perpendicular to motion direction showed large hot∕cold spots; however, this effect vanished with higher numbers of rescannings for both methods. Similar observations were obtained for the other dose metrics, such as target motion (SI∕AP), amplitude (6-22 mm peak-to-peak) and respiratory period (3.0-5.0 s). For four or more rescannings, both methods showed significantly better results, albeit that volumetric PCR was more affected by interference effects, which lead to severe degradation of a few dose distributions. The clinical example showed the same tendencies as the phantom study. Dose assessment metrics (D95, Dmax∕Dmin, homogeneity index) were improved with an increasing number of PCRL∕PCRV, but with PCRL being more robust. CONCLUSIONS: PCRL requires a longer treatment time than PCRV for high numbers of rescannings in the NIRS scanning system but is more robust. Although four or more rescans provided good dose homogeneity and conformity, the authors prefer to use more rescannings for clinical cases to further minimize dose degradation effects due to organ motion. |
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| 書誌情報 |
Medical Physics 巻 40, 号 3, p. 031720-1-031720-18, 発行日 2013-03 |
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| ISSN | ||||||
| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 0094-2405 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | http://online.medphys.org/resource/1/mphya6/v40/i3/p031720_s1 | |||||
| 関連名称 | http://online.medphys.org/resource/1/mphya6/v40/i3/p031720_s1 | |||||
