The values of F-FDG PET / CT in radiotherapy planning and prognosis after chemoradiotherapy in upper third EC - Among the 68 patients who were scheduled for IMRT planning on CT and refer to 18F-FDG PET / CT images, the mean tumor length on 18F-FDG PET / CT (5.1 ± 1.7 cm) was smaller than on CT (5.8 ± 1.7 cm) (p < 0.05).