体部三维适形放疗体位固定技术的比较

目的探讨单纯的真空垫固定技术和热塑体膜加专用底板加真空垫固定技术在体部三维适形放疗摆位精度的作用价值，．方法将56例患者固定方式分为两组，一组28例使用单纯的真空垫固定技术，另一组28例使用热塑体膜加专用底板加真空垫固定技术。通过拍摄模拟定位片和射野验证片对两组固定技术的患者进行摆位精度验证，比较两组中心点移位情况。结果拍摄验证片224张，热塑体膜加专用底板加真空垫固定组的摆位误差（1．6±1．1）mm，低于真空垫固定组摆位误差（3．8±2．2）min，且差异有显著性意义（P〈0．05）。结论胸腹部肿瘤患者由于皮下脂肪层的厚度、皮肤和皮下脂肪层的张力和重力等因素的影响而改变其位置．造成摆位误差．热塑体膜加专用底板加真空垫体位固定技术的准确性和重复摆位精度明显提高，从而提高了治疗摆位精确度．对指导放射治疗质量控制3-作很有意义。

Comparison of Immobilization in Body Three-dimensional Conformal Radiation Therapy

Objective To explore the role and value of simple fixed vacuum pad technology and thermoplastic membrane plus vac uum plus special floor mats fixation in body three-dimensional conformal radiotherapy positioning accuracy. Methods Fixation of the 56 patients were divided into two groups： one group of 28 patients using a simple fixed vacuum pad technology, another group of 28 patients using the thermoplastic membrane plus vacuum plus special floor mats fixation. Simulation film by film and film shoot field authentication technology were fixed for positioning accuracy verification in the two groups to compare the shifting center. Results In verification of 224 films, thermoplastic membrane plus vacuum plus special floor mats fixed group setup errors （1.6±1.1） mm, were lower than the vacuum pad fixed group setup errors （3.8 ± 2.2） mm, and the difference was significant （P〈0.05）. Conclusions Thoracic and abdominal tumors as subcutaneous fat thickness, skin and subcutaneous fat layer of tension and gravity and other factors which change their position, resulting in positioning errors, thermoplastic membrane plus vacuum plus special floor mats immobilization technology repeat accuracy and posi tioning accuracy is significantly improved, resulting in improved treatment of positioning accuracy in guiding meaningful quality control of radiotherapy.