碘－131全身掃描在偵測分化良好甲狀腺癌的復發與轉移方面，具有相當高的特異性，但只有中等的敏感性。氟－18-去氧葡萄糖正子掃描(FDG-PET)則被認爲是在甲狀腺球蛋白上升但碘－131掃描陰性時的首選檢查。在此，我們報告一例甲狀腺乳突癌的個案，被發現有甲狀腺球蛋白上升的情形。碘－131全身掃描因支氣管擴張症而出現了僞陽性的肺部吸收，但對於一個頸部淋巴結轉移的病灶卻現了僞陰性的結果。FDG-PET/CT的檢查正確地偵測出這個淋巴轉移病灶，並且在肺部支氣管擴張的病灶上並無FDG的僞陽性吸收。

Iodine-131 whole body scan (131I WBS) is highly specific, but only moderately sensitive for detecting recurrence or metastasis of well-differentiated thyroid cancer. FDG-PET is considered as the method of choice for those with elevated serum thyroglobulin but negative 131I WBS. Here, we presented a case of papillary thyroid cancer with elevated thyroglobulin. The 131I WBS showed a false-positive pulmonary uptake due to bronchiectasis, but was false-negative for a cervical lymph node metastasis. The FDG-PET/CT correctly detected the lymph node metastasis and showed no false-positive FDG uptake in the pulmonary lesion of bronchiectasis.