動態弧形放射治療與強度調控放射治療治療計畫品質比較與劑量驗證於頭頸癌病例之研究

A Treatment Planning Evaluation and Verification Comparing Modulated Arc Therapy with Intensity Modulated Radiotherapy for Head and Neck Cancer

林廣軒(Kuang-Hsuan Lin) ； 劉幕台(Mu-Tai Liu) ； 畢祖平(Chu-Ping Pi) ； 張東浩(Tung-Hao Chang) ； 黃昭源(Chao-Yuan Huang) ； 黃勝賢(Sheng-Shien Huang) ； 鍾兆麒(Chao-Chi Chung)

《放射治療與腫瘤學》 19卷1期 (2012/03) Pp. 51-61

https://doi.org/10.6316/TRO/201219(1)51

摘要

目的：動態弧形放射治療為目前放射治療中較新之技術，透過本研究了解動態弧形放射治療與強度強控放射治療在治療計畫品質上與治療效率上之差異，並且透過劑量驗證評估動態弧形放射治療劑量分布之準確性。材料與方法：臨床上十位頭頸癌患者進行強度調控放射治療與動態弧形放射治療計畫，強度調控放射治療使用Pinnacle^3 9.0治療計畫系統之直接機械參數最佳化產生九個射束照野，動態弧形放射治療使用Pinnacle^3 9.0 Smart Arc最佳化產生兩個全弧形射束，兩者皆以Elekta AXESSE直線加速器為治療計畫計算基準；VMAT治療計畫使用Wellhofer cc01游離腔執行點劑量驗證並使用ISP（international specialty products Wayne，NJ）公司所發展之自顯影底片Gafchromic EBT2底片與驗證軟體FilmQA來分析面劑量分布。結果：動態弧形放射治療與強度調控放射治療在治療計畫中計畫靶體積V95並無明顯差異，危急器官於動態弧形放射治療則有較少的劑量；動態弧形放射治療點劑量平均誤差為2.43%（1.6%－3.2%），面劑量gamma值平均為97.38%（96.7%－98.2%）。結論與討論：藉由本研究可以了解動態弧形放射治療在治療計畫品質之表現以及劑量驗證之準確性；動態弧形放射治療可維持治療計畫品質下，同時治療時間之花費比強度調控放射治療，可平均減少56%且輸出監測單位平均減少20%。

關鍵字

動態弧形放射治療 ； 強度強控放射治療 ； Gafchromic EBT2底片

並列摘要

Purpose: Volumetric modulated arc therapy (VMAT) is a relatively new technology of radiation therapy. The objective of this study is to compare VMAT with fixed field intensity modulated radiotherapy (IMRT) in term s of plan quality, delivery efficiency, and to assess the dose distribution by dose verification of the accuracy of VMAT. Materials and Methods: Ten clinical cases of head and neck cancer were evaluated in this study. IMRT plans were developed using direct machine parameter optimization in the Pinnacle^3 V9.0 treatment planning system, VMAT plans were generated using Smart Arc in the Pinnacle^3 V9.0. ITMRT and VMAT plans were delivered using Elekta AXESSE. Treatment plan quality assurance for VMAT was performed using the Wellhofer cc01 ion chamber and Gafchromic EBT2 film system. Results: The PTV V95 is no significant difference between VMAT and IMRT. Normal tissue sparing was improved using VMAT as compared with IMRT. The verification of VMAT dose point average error and average gamma was 2.43% (1.6%-3.2%) and 97.38% (96.7%-98.2%). Dicussion and Conclusion: VMAT treatment plans can be delivered accurately based on dose verification. VMAT has the potential to significantly reduce 56% treatment time and 20% monitor unit compared with IMRT, with no sacrifice in quality of plan.

並列關鍵字

Volumetric modulated arc therapy ； Intensity modulated radiotherapy ； Gafchromic EBT2 film