鼻咽癌IMRT定位误差的控制

目的：通过对鼻咽癌适形调强放射治疗的位置验证,探讨鼻咽癌适形调强放射治疗的定位技术。方法：采用双曝光法对患者拍摄射野验证片和Adobe公司Photoshop图像处理软件进行图像对比、融合,分析其产生误差的原因。结果：通过射野验证图像与参考图像的对比得出,在左右方向（X）、前后方向（Y）、头脚方向（Z）的摆位误差分别为：X（1.41±1.37）mm、Y（1.53±1.25）mm、Z（1.36±1.39）mm,最大误差为6.2mm;并且在身体各个方向上的位置及姿势与CT定位后重建影像存在体位姿势误差,其误差特点为越远离治疗中心表现越明显。结论：放射治疗定位技术有助于减少放射治疗中等中心的摆位误差,也有助于减少身体各个方向上的体位姿势误差。

Immobilization error control of IMRT for patients with nasopharyngeal carcinoma

Objective:To explore the immobilization technology of IMRT for patients with nasopharyngeal carcinoma by position verification in radiotherapy. Methods: Images which were taken by double exposure method were compared and fused by Photoshop software in which error causes were analyzed. Results: Setting-up error of left and right direction(X) was (1.41±1.37) mm, pre and post direction(Y) was (1.53±1.25) mm and head and foot direction (Z) was (1.36±1.39) mm and maximum error was 6.2mm. Setting-up errors after reconstructed image by CT were found in all directions of body in which error characteristics was more obviously with more far from treatment position . Conclusion: Positioning technology of radiotherapy could reduce setting-up error of isocenter, and help to reduce posture position error in all directions of body.