用图像引导技术提高胸腹部肿瘤大分割放疗的治疗精度  

Image-guided radiotherapy improves the precision of hypofractionated radiotherapy for thoracic and abdominal tumors

作　　者：张寅[1] 张连胜[1] 肖建平[1] 翟万聪[1] 李明辉[1] 戴建荣[1] 李晔雄[1] 

机构地区：[1]中国医学科学院中国协和医科大学肿瘤医院肿瘤研究所放疗科,北京100021

出　　处：《中华放射肿瘤学杂志》2008年第6期441-444,共4页Chinese Journal of Radiation Oncology

基　　金：卫生部临床重点学科资助项目（2007-2010）

摘　　要：目的探讨图像引导放疗技术应用于胸腹部肿瘤大分割放疗以提高治疗精度，测量其摆位误差并确定由内靶体积（ITV）外放产生计划靶体积（PTV）的间距。方法人组24例胸腹部肿瘤病例，采用大分割放疗，每次治疗前行锥形束CT扫描，在线校正摆位误差并记录误差值。统计校正前后的误差数据，采用二参数法计算由ITV外扩产生PTV间距。结果校正前摆位平移误差在左右（x）、头脚（y）和腹背（z）方向上分别为（2．1±2．0）、（3．9±3．2）、（2．9±2．8）mm，校正后分别为（0．8±0．7）、（0．9±0．7）、（0．9±0．7）mm；外扩间距校正前分别为5．6、10．2、7．7mm，校正后分别为2．1、2．3、2．3mm。旋转角度误差校正前后无变化，校正前头脚方向误差大于左右和腹背方向，校正后3个方向误差之间无差别。结论图像引导放疗通过在线校位能有效减小摆位误差并能观测肿瘤及周围组织器官位移和变形，计算在线校位后的靶区外放间距可以为PTV确定提供参考。Objective To study image-guided hypofractionated radiotherapy for thoracic and abdominal tumors, and to determine the margins extended from internal target volume （ITV） to planning target volume（PTV）. Methods Twenty-four patients who received image-guided hypofractionated radiotherapy for thoracic and abdominal tumors were included in this study. X-ray cone beam CT was regularly performed before the treatment. The shift and Rotation in right-left（R-L）, superior-inferior（S-I） and anterior-posterior （A-P） directions were recorded and analyzed. The shift margin from ITV to PTV was calculated with the equation,margin = 2＇mean ＋ 0. 7 ＇standard deviation. Results Before online correction, the shift errors in R-1,S-I and A-P directions were [ 2.1 ± 2.0 ] mm, [ 3.9 ± 3.2 ] mm and [ 2.9 ± 2.8 ] ram, and the corre- sponding margins were 5.6 mm, 10.2 mm and 7.7 ram. After the correction the shift errors were [0.8±0.7] mm, [0.9±0.7] mmand [0.9±0.7] mm , and the margins were 2.1 mm,2.3mmand2.3 mm. The set-up error was markedly decreased after the correction. There was no change in rotation after the correetion. Conclusions The positioning error decreases after the correction in IGRT, and the precision of radiotherapy is improved. Measuring set-up error in radiotherapy can provide institution-specific margins for PTV designing.

关 键 词：图像引导放疗 锥形束CT 摆位误差 在线校位 

分 类 号：R686[医药卫生—骨科学]