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研究生: 蔡雨恬
Yu-Tien Tsai
論文名稱: 以蒙地卡羅方式建構諾力刀系統及微多葉式準直儀並探討其劑量特性
Monte Carlo simulation of a Novalis System and equipped m3 mMLC using BEAMnrc07
指導教授: 董傳中
Chuan-Jong Tung
李宗其
Chung-Chi Lee
趙自強
Tsi-Chian Chao
口試委員:
學位類別: 碩士
Master
系所名稱: 原子科學院 - 生醫工程與環境科學系
Department of Biomedical Engineering and Environmental Sciences
論文出版年: 2008
畢業學年度: 96
語文別: 中文
論文頁數: 116
中文關鍵詞: 蒙地卡羅方式微多葉式準直儀諾力刀系統
外文關鍵詞: Monte Carlo simulation, m3 mMLC, Novalis system
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  • 為提供研究者進行強度調控放射治療之劑量分佈模擬,本研究利用蒙地卡羅模擬程式BEAMnrc建構直線加速器諾力刀系統(Novalis,BrainLab/Varian)及其配備之微多葉式準直儀(m3),並準確地追蹤射束經過機頭各構造時粒子的遷移與作用,包括多葉式準直儀的圓形葉片尖端構造(rounded-leaf end)、葉片側面凹凸齒狀構造(tongue and groove)等。我們利用Varian 600C/D參考手冊並加以微調以建構諾力刀系統靶至準直儀的部份,並選擇最適當的入射電子參數組合為6.0 MeV、FWHM(R)為0 mm、FWHM(E)為0.2 MeV、角度分佈1.5°。
    m3構件模組的部分則使用BrainLab m3設計圖設定包括葉片上緣位置、葉片尖端、葉片寬度、凹凸齒狀構造、y方向起始位置等參數,並比較模擬及測量之alternate block field劑量剖面,以設定適當的葉片間空隙。建構完成之m3構件模組以alternate block field以及block field進行物理及劑量特性的驗證,前者之差異約有91% 於2% / 1 mm之內,後者之差異則約有94% 於2% / 1 mm之範圍內,皆與文獻相近。


    摘 要 i 誌 謝 ii 目 錄 iii 圖目錄 vi 表目錄 xiv 第一章 序論 1 1.1 前言 1 1.2 研究目的與研究架構 4 第二章 理論基礎 6 2.1 諾力刀治療系統(Novalis System) 6 2.2 蒙地卡羅模擬方法(Monte Carlo Simulation Method) 7 2.3 誤差縮減技術(Variance Reduction Technique) 12 第三章 材料與方法 22 3.1 建構諾力刀模擬系統 22 3.2 入射電子射束及其參數 31 3.3 入射電子射束參數之選擇 39 3.4 建構多葉式準直儀m3構件模組 41 3.4.1 m3基本構造 41 3.4.2 m3構件模組參數之設定 43 3.4.3 m3之蒙地卡羅模擬 56 3.5 m3構件模組之驗證 58 3.5.1 底片之測量 59 3.5.2 Alternate block field 61 3.5.3 Block field 63 3.6 測量與模擬劑量分佈差異之評估方式 64 第四章 結果與討論 72 4.1 入射電子射束的選擇 73 4.1.1 入射電子射束的能量(energy) 73 4.1.2 徑向分佈(radial spread) 78 4.1.3 能量分佈(energy spread) 83 4.1.4 角度分佈(angular spread) 87 4.1.5 最適當入射電子射束參數選擇 92 4.2 多葉式準直儀m3之建構模擬 96 4.2.1 m3構件模組之建構 96 4.2.2 m3構件模組各項參數之影響 98 4.3 m3劑量驗證照野之模擬 104 4.4 文獻比較 110 第五章 結論 111 參考文獻 113

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