Leslie W D, Peterdy A E, Dupont J O
Department of Nuclear Medicine, University of Manitoba, St. Boniface General Hospital, Winnipeg, Canada.
J Nucl Med. 1998 Apr;39(4):712-6.
Persistent or recurrent Graves' hyperthyroidism after an initial treatment dose of radioactive iodine (RAI) is not uncommon and usually necessitates additional administrations. The radiation sensitivity of the previously irradiated thyroid gland is unknown but is of importance in selecting the retreatment dose.
A retrospective analysis of patients receiving RAI for Graves' hyperthyroidism was undertaken. A first treatment dose was given to 1076 patients, and 168 of these patients subsequently required a second dose for persistent or recurrent hyperthyroidism (interval between RAI treatments, 8.5 +/- 17.1 mo).
Paired comparisons for retreated patients showed similar RAI doses (291 +/- 95 MBq and 283 +/- 129 MBq; p = ns) and treatment intensities (3.26 +/- 1.87 MBq g(-1) and 3.48 +/- 1.88 MBq g(-1); p = ns) for first and second treatments. Hypothyroidism occurred significantly earlier and more frequently after the first RAI dose (p = 0.002), but there was no difference for persistent or recurrent hyperthyroid events (p = 0.14). Multivariate regression established that the RAI treatment number (first or second) was a significant independent determinant of hypothyroid (p = 0.008) and combined (p = 0.001) events, whereas RAI dose and dose intensity were not.
We conclude that previous RAI treatment failure does not lessen the chance of successfully eradicating Graves' hyperthyroidism with additional RAI treatment. Furthermore, the previously irradiated thyroid gland may be less susceptible to early hypothyroidism than the RAI-naive thyroid gland.
初次放射性碘（RAI）治疗剂量后持续性或复发性格雷夫斯甲亢并不罕见，通常需要再次给药。先前接受过照射的甲状腺的辐射敏感性尚不清楚，但在选择再次治疗剂量时很重要。
对接受RAI治疗格雷夫斯甲亢的患者进行回顾性分析。1076例患者接受了首次治疗剂量，其中168例患者随后因持续性或复发性甲亢需要第二次剂量（RAI治疗间隔为8.5±17.1个月）。
对再次治疗患者的配对比较显示，首次和第二次治疗的RAI剂量相似（291±95MBq和283±129MBq；p=无统计学意义），治疗强度相似（3.26±1.87MBq g⁻¹和3.48±1.88MBq g⁻¹；p=无统计学意义）。首次RAI剂量后发生甲状腺功能减退明显更早且更频繁（p=0.002），但持续性或复发性甲亢事件无差异（p=0.14）。多变量回归确定，RAI治疗次数（第一次或第二次）是甲状腺功能减退（p=0.008）和综合（p=0.001）事件的显著独立决定因素，而RAI剂量和剂量强度不是。
我们得出结论，先前RAI治疗失败并不降低再次进行RAI治疗成功根除格雷夫斯甲亢的机会。此外，先前接受过照射的甲状腺可能比未接受过RAI治疗的甲状腺对早期甲状腺功能减退的易感性更低。
