ABSTRACT
The current study aimed to determine the efficacy of radioiodine-131 [131I] ablation therapy with thyroid hormone replacement one day before [131]I administration in patients with well-differentiated thyroid cancer [DTC]. This retrospective study included 29 patients who underwent [131]I therapies twice for DTC during 6-12 months. Since all the patients obviously had residual lesions by their serum thymoglobulin levels or their scintigrams at the first therapies, they underwent the second [131]I therapies without diagnostic scintigraphy after the first therapies. After confirming the sufficient elevation of TSH concentration, thyroid hormone replacement was resumed one day before [131]I administration [3.7-7.4GBq]. The ablation rate of thyroid remnant at the first [131]I therapy was evaluated by comparing [131]I post-therapeutic images of the two treatments. Three patients were administrated thyroid hormone after [131]I therapy because of insufficient TSH concentration under thyroid hormone withdrawal. In the remaining 26 patients, 41 thyroid remnant accumulations were detected in all 26 patients at the first [131]I therapy. Based on the second [131]I post-therapeutic images, successful ablation was confirmed in 24 of 26 patients [92.3%] and 38 of 41 sites [92.7%], which was comparable with historically reported ablation rates. Thyroid hormone replacement one day before [131]I therapy could provide a sufficiently high ablation rate in patients with DTC