Abstract： Objective To evaluate the value of positron-emission tomography(PET)for the identification of cervical nodal metastases of head and neck cancer compared with CT/MRI and clinical palpation.Methods Forty patients of head and neck cancer Lulderwent PET and CT/MRI examination 2 weeks before surgery.PET,CT/MRI and clinical palpation were interpreted separately to assess regional lymph node status.Histopathologic analysis was used as the gold standard for assessment of the lymph node involvement.Differences in sensitivity.specificity and accuracy among the imaging modalities and clinical palpation were analyzed.Results The sensitivity of PET for the identification of nodal metastases was 14.3% highor than that of CT/MRI (P=0.648)and 14.3% higher than that of clinical palpation(P=0.648),whereas the specificity of PET was 15.4% higher than that of CT/MRI(P=0.188)and 7.7% higher than that of clinical palpation(P=0.482).The accuracy of 18F-FDG PET,CT/MRI,and clinical palpation for the identifieation of cervical nodal metastases was 85.0%,70.0% and 75.0% respectively.Conclusions The sensitivity,specificity and accuracy of PET for the detection of cervical nodal metastases was higher than that of CT/MRI and clinical palpation.Although the results did not show a statistically significant difference,PET can still serve as a supplementary method for the identification of nodal metastases of head and neck cancer.