Calegaro J U, De Freitas Gomes E, Bae S H, Ulyssea R, Casulari L A
Unidade de Medicina Nuclear, Hospital de Base do Distrito Federal, SMHS Q 101, 70335-900 Brasília, DF, Brazil.
Panminerva Med. 2000 Dec;42(4):241-5.
Studies have been performed in order to assess a treatment with 131I able to induce a consistent improvement in Graves' hyperthyroidism.
For this purpose, four different protocols based on four different doses of radioiodine have been tested in Graves' disease patients. Patients never submitted previously to antithyroid drug treatment were given 1 mCi/10 gm of the estimated thyroid weight (group I; n = 50). Group II (n = 48) included patients not previously treated with antithyroid drugs and who were given doses of iodine based on a formula taking into account the rate of thyroid iodine uptake, i.e. 131I dose = microCi/gm of the estimated thyroid weight x 100/24 hrs 131I uptake (%). Patients previously submitted to antithyroid drug therapy were treated with radioiodine whose dose was calculated according to the formula reported above, but the dose was increased in order to overcome the possible resistance of this kind of patients to the effect of 131I. One group (group III; n = 24) received the calculated dose plus 1 microCi/gm of the estimated thyroid weight. Finally, group IV (n = 27) received the calculated dose plus 0.25 microCi/gm of the estimated thyroid weight.
The analysis of the patients one year later demonstrated that groups I and II presented the higher percent of euthyroid patients (60% and 58%, respectively) followed by group IV (37%) and group III (29.2%). The percent of patients still exhibiting hyperthyroidism was 28% in group I, 26% in group IV, 12.5% in group III and 8.3% in group II. The highest number of hypothyroid patients was present in group III (58.3%) followed by group IV (37%), group II (33.3%) and group I (12%).
The data here presented suggest that protocols I and II based on relatively low doses of radioiodine are rather effective in reducing Graves' hyperthyroidism in patients not submitted previously to antithyroid drug therapy. The most satisfactory therapy seems that utilized in protocol II, that in front of a fair amount of euthyroid patients (58.3%) presents a very low number of subjects still hyperthyroid (8.3%). However, the number of patients who became hypothyroid (33.3%) as a consequence of the therapy was too high. Hopefully, a better design of the protocol will reduce this figure. The high incidence of hyperthyroidism observed in groups III and IV submitted to a therapy with 131I doses consistently higher than those utilized in groups I and II seems to confirm the hypothesis that hyperthyroid subjects submitted to a therapy with antithyroid drugs become rather resistant to a radioiodine treatment.
已开展多项研究以评估用¹³¹I进行的治疗能否使格雷夫斯甲亢得到持续改善。
为此，在格雷夫斯病患者中测试了基于四种不同剂量放射性碘的四种不同方案。此前从未接受过抗甲状腺药物治疗的患者按估计甲状腺重量给予1毫居里/10克（I组；n = 50）。II组（n = 48）包括此前未接受过抗甲状腺药物治疗的患者，他们根据一个考虑甲状腺碘摄取率的公式给予碘剂量，即¹³¹I剂量=估计甲状腺重量（克）×100/24小时¹³¹I摄取率（%）。此前接受过抗甲状腺药物治疗的患者用放射性碘治疗，其剂量根据上述公式计算，但剂量增加以克服这类患者对¹³¹I作用可能产生的抵抗。一组（III组；n = 24）接受计算出的剂量加上估计甲状腺重量每克1微居里。最后，IV组（n = 27）接受计算出的剂量加上估计甲状腺重量每克0.25微居里。
一年后对患者的分析表明，I组和II组甲状腺功能正常患者的百分比更高（分别为60%和58%），其次是IV组（37%）和III组（29.2%）。仍表现为甲亢的患者百分比在I组为28%，IV组为26%，III组为12.5%，II组为8.3%。甲状腺功能减退患者数量最多的是III组（58.3%），其次是IV组（37%）、II组（33.3%）和I组（12%）。
此处呈现的数据表明，基于相对低剂量放射性碘的方案I和II在降低此前未接受过抗甲状腺药物治疗的患者的格雷夫斯甲亢方面相当有效。最令人满意的治疗似乎是方案II中所采用的，在相当数量的甲状腺功能正常患者（58.3%）中，仍患有甲亢的患者数量非常少（8.3%）。然而，因该治疗而出现甲状腺功能减退的患者数量（33.3%）过高。有望通过更好地设计方案来降低这一数字。在III组和IV组中观察到的甲亢高发生率，其接受的¹³¹I剂量始终高于I组和II组所使用的剂量，这似乎证实了这样一个假设，即接受抗甲状腺药物治疗的甲亢患者对放射性碘治疗变得相当耐药。
