Leger F A, Izembart M, Dagousset F, Barritault L, Baillet G, Chevalier A, Clerc J
Service de Radio-isotopes, Groupe Hospitalier Necker-Enfants Malades, Paris, France.
Eur J Nucl Med. 1998 Mar;25(3):242-6. doi: 10.1007/s002590050223.
We performed a prospective random study to assess possible thyroid stunning by a 185-MBq iodine-131 dose used to diagnose thyroid remnants. Patients with differentiated thyroid carcinoma were included after total or near-total thyroidectomy. They were randomly assigned to two groups. In group 0 (G0, 32 patients), iodine-123 administration only was used to diagnose thyroid remnants and/or metastasis, so that no thyroid stunning by 131I would occur. In group 1 (G1, 19 patients), diagnostic imaging was performed with 123I and 185 MBq 131I. 123I imaging was less sensitive than 131I imaging in identifying thyroid remnants in both groups (94%). Thyroid uptake of 123I was measured in both groups (at 2 h) and was not significantly different between the groups. Patients with thyroid remnants who remained in the study (28/32 in G0, 17/19 in G1) were treated with 370 MBq 131I, 5 weeks after treatment (mean time, range 12-84 days). In 12/17 G1 patients thyroid uptake measurement was repeated immediately before treatment. Uptake was equal to 1.97% +/- 0.71% and significantly lower (P < 0.05) than the previous measurement (3.76% +/- 1.50%). Patients were imaged 7 days after administration of the therapeutic dose and the images were compared with the diagnostic images. In 28/28 G0 patients thyroid remnants were unchanged and clearly seen. In 5/17 G1 patients, however the remnants were hardly identified, although they had been clearly seen at the time of diagnosis. We conclude the following: (1) a diagnostic dose of 185 MBq 131I decreases thyroid uptake for several weeks after administration and can impair immediate subsequent 131I therapy; (2) 123I is slightly less sensitive than 131I in identifying thyroid remnants; and (3) the need to scan for thyroid remnants remains to be confirmed, since only 2/51 patients enrolled in this study were not treated with 131I.
我们进行了一项前瞻性随机研究，以评估用于诊断甲状腺残余组织的185MBq碘-131剂量是否可能导致甲状腺“失能”。分化型甲状腺癌患者在接受全甲状腺切除或近全甲状腺切除术后被纳入研究。他们被随机分为两组。在0组（G0，32例患者）中，仅使用碘-123来诊断甲状腺残余组织和/或转移灶，因此不会发生131I导致的甲状腺“失能”。在1组（G1，19例患者）中，使用碘-123和185MBq的131I进行诊断性成像。在两组中，碘-123成像在识别甲状腺残余组织方面不如131I成像敏感（94%）。在两组中均测量了碘-123的甲状腺摄取量（2小时时），两组之间无显著差异。留在研究中的甲状腺残余组织患者（G0组28/32例，G1组17/19例）在治疗后5周（平均时间，范围12 - 84天）接受370MBq的131I治疗。在17例G1组患者中的12例中，在治疗前立即重复测量甲状腺摄取量。摄取量为1.97%±0.71%，显著低于先前测量值（3.76%±1.50%）（P < 0.05）。在给予治疗剂量后7天对患者进行成像，并将图像与诊断图像进行比较。在28/28例G0组患者中，甲状腺残余组织未发生变化且清晰可见。然而，在17例G1组患者中的5例中，尽管在诊断时甲状腺残余组织清晰可见，但此时却几乎无法识别。我们得出以下结论：（1）185MBq的131I诊断剂量在给药后数周内会降低甲状腺摄取量，并可能损害随后立即进行的131I治疗；（2）在识别甲状腺残余组织方面，碘-123比131I稍欠敏感；（3）由于本研究中纳入的51例患者中只有2例未接受131I治疗，因此扫描甲状腺残余组织的必要性仍有待证实。
