Objective: To evaluate the accuracy of different body immobilization methods of radiotherapy for esophageal carcinoma was studied by using the cone-beam CT( CBCT) method. Methods: A total number of 30 esophageal cancer patients were randomly assigned into 2 groups( vacuum pad group,wing panels + vacuum pads group) for immobilization,cone beam CT( CBCT) scan was adopted in each patients. XVI software to CBCT scan images and CT images were automatically registered. Setup errors of CBCT were calculated accordi...