食管癌放射治疗中进行二次定位，旨在确定靶区范围，改变投照角度，力求减少脊髓、心肺的受量。因为治疗期间瘤灶位置可能发生不同程度的改变，只有相应地调整照射野，方能保证治疗计划的准确实施。我们分析了从１９９４年２月至１９９６年１２月在本院放疗的食管癌病人１... The secondary positioning of esophageal cancer radiotherapy aims to determine the scope of the target area, change the angle of projection, and strive to reduce the spinal cord, cardiopulmonary absorption. Because the location of the tumor during treatment may change to varying degrees, only the radiation field is adjusted accordingly to ensure the accurate implementation of the treatment plan. We analyzed patients with esophageal cancer who were treated with radiotherapy in our hospital from February 1994 to December 1996.