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題 名 | 治療床參數對臨床劑量的影響分析與最佳化=Optimization of Couch Parameters for Intensity Modulated Radiotherapy |
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作 者 | 劉定揚; 陳合興; 鄭梅君; 賴源淳; 趙敏; | 書刊名 | 中華放射線技術學雜誌 |
卷 期 | 39:4 2015.12[民104.12] |
頁 次 | 頁209-218 |
分類號 | 416.36 |
關鍵詞 | 亨氏單位; 治療計劃系統; 治療床; 加馬參數法; Hounsfield unit; Treatment planning system; Treatment couch; Gamma index; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究之目的在於取得治療計劃系統(treatment planning system, TPS)中最佳的治療床參數。先以二維陣列游離腔劑量儀(MatriXX)測量入射角為180°的6MV單一射束經治療床的射束衰減程度,再將碳纖維治療床以電腦斷層(computed tomography, CT)掃描取得治療床各結構的亨氏單位(Hounsfield Unit,HU)。在TPS中的碳纖維治療床設定多組HU值參數,將其參數導入11個臨床的7角度鼻咽癌強度調控放射治療(intensity modulated radiation therapy, IMRT)計畫計算,以加馬參數法(gamma index, γ ≤ 1, criteria 3%, 3 mm)進行各組計算劑量與實際量測劑量的比較評估。結果為在11例IMRT計畫中加入的治療床模板其HU值分別使用系統預設值、CT取像值以及經調整的CT取像值時,其計算與量測之平均通過率依序為93.7%、94.9%與95.2%。此研究提供經由治療床的衰減計算來提高治療劑量準確度的方法。 |
英文摘要 | This study aimed to find the optimal modeling of the treatment couch parameters in the treatment planning system (TPS).Dose measurements were taken using a 2D ion chamber array (MatriXX) with plastic water phantom. The measurements were performed under 6MV photon beam, with the beam penetration through the couch. The couch images were acquired with GE RT-580 CT scanner to obtain the Hounsfield units (HU) values.Several HU valueswere set and used in TPS for dose calculation. Eleven plans of head and neck with 7 IMRT (intensity modulated radiation therapy) fields were calculated with various HU of couch. The plans were exported to Linac and the dose distribution was verified with MatriXX device. The dose distribution of measurements was compared with calculation. The gamma index method was used to evaluate the dose agreement between calculation and measurement with the criteria of 3%, 3 mm.Three sets of HU values were used in dose calculation: the built-in set, the acquired from CT scanner and the modified HU value according to the calculation results. The passing rate of dose agreement between calculation and measurement are 93.7%, 94.9% and 95.2%, respectively. The study provides a method to improve the accuracy of treatment dose in couch transmission calculation. |
本系統中英文摘要資訊取自各篇刊載內容。