Objective To evaluate the clinical value of 18floro-deoxyglucose positron emission tomography-CY(~(18)FDG PET-CT)in the diagnosis of lymph node metastasis from advanced esophageal carcinoma. Methods A prospective study is perfonued here to assess whether ~(18)FDG PET-CT can improve the diagnostic accuracy in lymph node metastasis for patients with advanced esophageal carcinoma.Thirty patients had undergone esophagectomy with extensive lymph node dissection.PET-CT findings were compared with that d CT with pathological finding as the final say.Results All patients were operated successfully without peri-operative complications.The pathological examination conformed metastasis in 22 patients and 49 out of 243 excised lymph nodes.In CT analysis,the sensitivity was 40.8%,specificity was 96.9%,with a diagnostic accuracy of 85.6%, The positive and negative predictive value was 76.9%,86.4% respectively;PET-CT resulted in a sensitivity of 93.9%,specificity of 91.2%,accuracy of 91.8%.The positive predictive value was 73.0% and negative predictive value was 98.3%,The difference of sensitivity(P＜0.001),accuracy(P＜0.05)and negative predictive value between the two radiological modalities was statistically significant(P＜0.001).Conclusions With a high sensitivity and accuracy in the diagnosis of lymph node metastasis,PET-CT appears necessary in preoperative examination for advanced esophageal carcinoma in the hope that surgical treatment be guided by the results of PET-CT,especially for the elder patients with poor pulmonary function or heart or brain complications. Moreover,it could be used as the basis of the conformal radiation therapy planning for inoperable patients.