Nishiyama K, Tanaka E, Tarui Y, Miyauchi K, Okagawa K
Department of Radiology, Kinki Central Hospital, Itami, Japan.
Int J Radiat Oncol Biol Phys. 1996 Jan 15;34(2):439-44. doi: 10.1016/0360-3016(95)02079-9.
Exposure of the thyroid to therapeutic doses of external irradiation has been demonstrated to induce thyroid dysfunction. This study was designed to assess the relationship between irradiation and early thyroid dysfunction, prospectively.
Twenty patients in whom the thyroid was incidentally exposed to therapeutic doses of irradiation were studied. The dose given to the thyroid was 40-54 Gy over 4-7 weeks. Thyroid function tests, including serum thyroid stimulating hormone (TSH), free thyroxine (free T4), free triiodothyronine (free T3), antithyroglobulin antibody, and antimicrosomal antibody, were performed prior to irradiation and at 3, 6, and 12 months after radiotherapy.
Serum TSH levels did not change significantly at 3 months after irradiation (mean TSH level: 1.33 microU/ml before irradiation, 1.74 microU/ml at 3 months, p = 0.11). However, a significant elevation was noted at 6 months (mean TSH: 3.50 microU/ml at 6 months, p = 0.0001, vs. preirradiation), when TSH levels were higher than preirradiation levels in 19 of 20 patients. After irradiation, 13 patients remained in a euthyroid state (euthyroid group), while in the other 7 patients hypothyroidism occurred (hypothyroid group) and thyroid hormone-replacement therapy was performed. After 6 months, elevation of TSH was less significant in the euthyroid group, whereas elevation of TSH persisted continuously and exponentially in the hypothyroid group. Thyroid autoantibodies did not turn positive in any patient during follow-up.
Damage of the thyroid develops in most patients when the organ is exposed to radiation. This radiation-induced damage is initially manifested within 6 months after irradiation.
已证实甲状腺暴露于治疗剂量的外照射会诱发甲状腺功能障碍。本研究旨在前瞻性评估照射与早期甲状腺功能障碍之间的关系。
对20例甲状腺意外暴露于治疗剂量照射的患者进行了研究。甲状腺接受的剂量为40 - 54 Gy，照射时间为4 - 7周。在照射前以及放疗后3、6和12个月进行甲状腺功能检查，包括血清促甲状腺激素（TSH）、游离甲状腺素（游离T4）、游离三碘甲状腺原氨酸（游离T3）、抗甲状腺球蛋白抗体和抗微粒体抗体。
照射后3个月血清TSH水平无显著变化（照射前平均TSH水平：1.33 μU/ml，3个月时为1.74 μU/ml，p = 0.11）。然而，在6个月时观察到显著升高（6个月时平均TSH：3.50 μU/ml，p = 0.0001，与照射前相比），此时20例患者中有19例的TSH水平高于照射前水平。照射后，13例患者维持甲状腺功能正常状态（甲状腺功能正常组），而另外7例患者发生甲状腺功能减退（甲状腺功能减退组）并接受了甲状腺激素替代治疗。6个月后，甲状腺功能正常组TSH升高不太显著，而甲状腺功能减退组TSH持续且呈指数性升高。随访期间所有患者的甲状腺自身抗体均未转为阳性。
当甲状腺器官暴露于辐射时，大多数患者会出现甲状腺损伤。这种辐射诱导的损伤最初在照射后6个月内表现出来。
