利用影像導引系統比較兩種輔助固定模具對乳癌放射線治療的準確性分析

摘要放射治療時擺位再現性及固定性關係著治療之準確性，因此固定治療姿勢之輔助固定模具基於符合人體工學而發展得更多元且完善。擺位之準確性及再現性可利用影像導引系統評估病患於治療時位置固定性及準確性。本研究目的使用像導引系統錐狀射束電腦斷層掃描(Cone beam Computed Tomography，CBCT)評估兩種輔具於乳癌放射治療位置準確性分析，輔具一為熱塑模固定模具(Orfit thermoplastic cast 45 cm×60 cm×2 mm)，輔具二為真空墊(ELEKTA BlueBAG™ 150×100 cm)。收集 2015 年 10 月至 2017 年 10 月總共 40 位乳癌病人療程期間 CBCT 在 X(左右軸)、Y(頭腳軸)、Z(前後軸) 三個軸向平均位移誤差。本研究結果為：熱塑固定模具之X、Y、Z三個軸向的平均位移誤差Mean ± SD分別為：3.32±2.8mm、5.28±4.48mm、2.77±1.99mm；真空墊之X、Y、Z三個軸向的位移平均差為：3.06±3.48mm、3.95±3.37mm、2.69±1.71mm。使用輔具 2 誤差值相對於輔具 1 較小，其原因為模具 2 輔具材質較為軟與順著人體型狀的弧度設計，對病患而言降低了不舒適感，進而提高了位置再現性及準確性。

關鍵字

乳癌；準確性；錐狀射束電腦斷層掃描；熱塑模固定模具；真空墊

並列摘要

Abstract 　　The accuracy of radiation therapy in breast cancer is highly related to the reproducibility and stationarity of body positioning that has been improved of more ergonomic immobilization devices. The goal of this study is to use image guiding cone-beam computed tomography (CBCT), to evaluate the patients position between two types of immobilization .The two types of immobilization that we use in my study are Orfit thermoplastic cast 45 cm×60 cm×2 mm(immobilization 1), and ELEKTA vacuum BlueBAG™ 150×100 cm(immobilization 2). Forty breast cancer patients using supine-position volumetric modulated arc therapy (VMAT), from October 2015 to October 2017 were enrolled into this study. 　　The evaluation was by using automatic grey value registration alignment and the shifting errors for the X, Y, and Z axes were analyzed. The average shifting errors for the X, Y, and Z axes were 3.32±2.8mm、5.28±4.48mm、2.77±1.99mm using immobilization 1, and 3.06±3.48mm、3.95±3.37mm、2.69±1.71mm using immobilization 2 .The errors were smaller for immobilization 2 , probably due to the soft and body curve fitting interiors of immobilization 2 . It can significantly decrease the discomfort and hence it increases the accuracy and reproducibility of radiation therapy.