目前食管癌国内多数采用仰卧和俯卧两种体位 ,源皮距放疗。用于作ＴＰＳ的ＣＴ图像多为诊断用的仰卧位图像 ,由于食管在这两种体位的位置不同 ,必然影响ＴＰＳ剂量的正确性。为估计该误差的大小 ,我们进行了研究。材料与方法选择 2 0 0 0年收治的 7例中段食管癌病人及 1999年收 At present, most of the domestic esophageal supine and prone position with two sources, the source skin radiotherapy. The CT images used for TPS are mostly supine position images for diagnosis. Due to the different positions of the esophagus in these two positions, the correctness of the dose of TPS is inevitably affected. To estimate the size of the error, we conducted a study. Materials and Methods Select 7 cases of mid-esophageal cancer patients admitted in 2000 and received in 1999