Goldman J M, Line B R, Aamodt R L, Robbins J
J Clin Endocrinol Metab. 1980 Apr;50(4):734-9. doi: 10.1210/jcem-50-4-734.
Radioiodine uptake by thyroid remnants and metastases postthyroidectomy for thyroid cancer is increased by withdrawing thyroid hormone, which raises TSH levels. The minimal withdrawal time for maximal uptake is unknown. Therefore, we performed 33 studies in 27 patients after 2 weeks and again after 4 weeks of T3 withdrawal. We examined cervical (or pulmonary) uptake and whole body scanning at 48 h and whole body retention at 48, 72, and 96 h after radioiodine. In 4 studies, only physiological nonthyroidal activity was seen on both scans. Cervical uptake was low in these 4 studies. Of the remaining 29 studies with thyroid activity on both scans, 4 had high cervical uptakes after 2 weeks, which decreased by 4 weeks to less than 50% of the 2 week value. The same trend was seen in whole body retentions. In 2 studies, the uptake increased at 4 weeks compared to that at 2 weeks, but the change was small and was reflected in whole body retention of only 1 of these subjects. In 23 studies, including 6 with metastatic disease, the individual uptakes and whole body retentions were similar after 2 and 4 weeks. The mean uptakes and retentions also did not differ despite significantly higher (P less than 0.001) TSH values at 4 weeks. All definite areas of localization of radioactivity seen on the scans after 4 weeks were seen after 2 weeks. Therefore, radioiodine uptake, scanning, and therapy should be performed after 2 weeks of T3 withdrawal when patients are minimally hypothyroid. Serum TSH should also be measured to identify the rare individual not responding to brief T3 withdrawal.
甲状腺癌甲状腺切除术后，停用甲状腺激素可使甲状腺残留组织和转移灶对放射性碘的摄取增加，这会提高促甲状腺激素（TSH）水平。达到最大摄取的最短停药时间尚不清楚。因此，我们对27例患者进行了33项研究，分别在停用T3 2周和4周后进行。我们在放射性碘注射后48小时检查颈部（或肺部）摄取及全身扫描，并在48、72和96小时检查全身滞留情况。在4项研究中，两次扫描均仅见生理性非甲状腺活动。这4项研究中颈部摄取较低。在其余29项两次扫描均有甲状腺活动的研究中，4项在2周后颈部摄取较高，到4周时降至2周值的50%以下。全身滞留情况也呈现相同趋势。在2项研究中，与2周时相比，4周时摄取增加，但变化较小，仅在其中1例受试者的全身滞留情况中有所体现。在23项研究中，包括6项有转移疾病的研究，2周和4周后的个体摄取及全身滞留情况相似。尽管4周时TSH值显著更高（P<0.001），但平均摄取和滞留情况并无差异。4周后扫描上可见的所有明确放射性定位区域在2周后也可见。因此，当患者处于轻度甲状腺功能减退状态时，应在停用T3 2周后进行放射性碘摄取、扫描及治疗。还应检测血清TSH，以识别罕见的对短期停用T3无反应的个体。
