Compare the number of lesions found in PET and PET / CT according to lesion site Number of les ions Lesion site PET PET / CT PET / CT finfing more than PET n% Cervical lymph node 159 173 14 8.8 Mediastinal lymph node 45 46 1 2.2 Thyroid bed 35 35 0 0 Lung 20 27 7 35 Bone 5 5 0 0 Other sites 8 8 0 0 Total of lesions 272 294 22 8.1 Remarks: - Cervical lymph node was most the lesion found in PET và PET / CT, then lesions in mediastinal lymph node, thyroid bed, and lung.