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Nuclear-interaction correction of integrated depth dose in carbon-ion radiotherapy treatment planning
https://repo.qst.go.jp/records/65789
https://repo.qst.go.jp/records/6578938f2d3b3-1caf-4332-9df2-5b2c0200d3bf
Item type | 会議発表用資料 / Presentation(1) | |||||
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公開日 | 2015-10-21 | |||||
タイトル | ||||||
タイトル | Nuclear-interaction correction of integrated depth dose in carbon-ion radiotherapy treatment planning | |||||
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 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 |
稲庭, 拓
× 稲庭, 拓× 兼松, 伸幸× 原, 洋介× 古川, 卓司× 稲庭 拓× 兼松 伸幸× 原 洋介× 古川 卓司 |
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抄録 | ||||||
内容記述タイプ | Abstract | |||||
内容記述 | Background: In treatment planning of charged-particle therapy, tissue heterogeneity is conventionally modeled as water with various densities, i.e. stopping effective densities Rs, and the integrated depth dose measured in water (IDD) is applied accordingly for the patient dose calculation. Since the chemical composition of body tissues is different from that of water, this approximation causes dosimetric errors, especially due to alternation of nuclear interactions. We propose and validate an IDD correction method for these dosimetric errors in patient dose calculations. Methods: Rs of the patient is converted to nuclear effective density Rn, defined as the ratio of the incidence of nuclear interactions in the tissue to that in water using a semi-empirical relationship between the two. The attenuation correction factor F, defined as the ratio of the attenuation of primary carbon ions in a patient to that in water, is calculated from a linear integration of Rn along the beam path. In our treatment planning system, a carbon-ion beam is modeled to be composed of three components. We corrected the dose contribution from primary carbon ions to IDD as proportional to F, and corrected that from lighter fragments as inversely proportional to F. We tested the correction method for some non-water materials with un-scanned and scanned carbon-ion beams. Results: In un-scanned beams, the corrected IDDs agreed with the measurements within ±1% for all materials and combinations of them. In scanned beams, the dosimetric error is significantly reduced with the correction method. The planned dose distributions agreed with the measurements within ±1.5% of target dose in target, plateau, and tail regions. Conclusions: We tested the correction method of IDD in some non-water materials to verify that this method would offer the accuracy and simplicity required in carbon-ion radiotherapy treatment planning. |
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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 | 第110回日本医学物理学会学術大会 | |||||
発表年月日 | ||||||
日付 | 2015-09-19 | |||||
日付タイプ | Issued |