三次曝光技术在后颈电子线补量中的应用

摘要

Objective:Using a homemade cross plate and an IP plate,the portal verification images taken by thrice exposure were used to determine the radiation volume of electron beam boost at the nape of the neck in radiotherapy. Methods:Installing the homemade cross plate and the IP plate at corresponding location,the portal verification image was taken and the radiation volume of electron beam boost at the nape of the neck was determined.Then the complex verification image at same position was taken on a simulator.The radiation volume,whether satisfied the need of thera-py,was evaluated.Results:Using above method for eight patients,the results were approved by the complex locating image taken on the simulator,and the doctor in charge affirmed that the radiation volume of electron beam boost at the nape of the neck satisfied the need of therapy.The dose error also satisfied the need proved by PTW2D -ARRAY729 matrix.Conclusion:The method to determine irradiation field of electron beam by thrice exposure could be applied for the electron beam boost at the nape of the neck in radiotherapy of nasopharyngeal carcinoma and other oropharyngeal tumors.The operation was easy and the method was of good practicability.%目的：IP 板与自制十字板合用，采用三次曝光照相技术拍摄射野证实片，用于后颈电子线补量照射范围的确定。方法：将自制十字补板和 IP 板放置在相应位置，分三次曝光拍摄射野证实片，确定电子线后颈量的照射范围，然后在模拟机下同体位拍摄复合定位片，评价照射范围是否符合治疗要求。结果：8例需要后颈电子线补量的病人使用三次曝光方法拍摄射野证实片，经模拟定位机同治疗体位拍摄复合定位片证实，经主管医生确认电子线后颈补量照射野范围均符合治疗要求，PTW 2D －ARRAY729矩阵验证剂量误差符合要求。结论：采用三次曝光技术确定电子线照射野的方法，可用于鼻咽癌及其他口咽部肿瘤治疗时对后颈电子线补量，该方法操作简单方便、实用。