Weiser J C, Gur D, Cano E R, Deutsch M, Wu A, Mogus R M
Department of Diagnostic Radiology, University of Pittsburgh.
Radiology. 1990 Apr;175(1):257-9. doi: 10.1148/radiology.175.1.2107561.
Portal verification images were generated from the photon contamination in electron beams produced by a linear accelerator during treatment of patients receiving high-energy electron radiation therapy (8-14 MeV). An experimental storage phosphor system was used to record the images and display them on laser-printed film. Images were obtained from four or more treatment fractions from 21 cases of head and neck cancer. Precision in field placement was estimated by determining the position of a selected anatomic landmark relative to the center of the field for each series of images. The average standard deviation in the field-position measurements was 3.8 mm. Several procedural problems were also detected and corrected after review of the verification images. The results indicate that the emphasis placed on monitoring and control of field-positioning error in high-energy electron treatments should be similar to the emphasis placed on this aspect of error in photon treatment.
门静脉验证图像是由直线加速器在对接受高能电子放射治疗（8 - 14兆电子伏特）的患者进行治疗期间产生的电子束中的光子污染生成的。使用实验性存储磷光体系统记录图像并将其显示在激光打印胶片上。从21例头颈癌患者的四个或更多治疗分次中获取图像。通过确定每个图像系列中选定解剖标志相对于射野中心的位置来估计射野放置的精度。射野位置测量的平均标准偏差为3.8毫米。在审查验证图像后还检测并纠正了几个程序问题。结果表明，在高能电子治疗中对射野定位误差的监测和控制所给予的重视程度应与在光子治疗中对误差这一方面的重视程度相似。
