In addition to a low iodine diet for 2 months, patients who have undergone enhanced CT need to undergo iodine-131 ablation 2-3 months after the test to minimize the retention of stable iodine in the body. In addition, in order to maximize the uptake and retention of iodine-131 by thyrotropin (TSH), ablation should be performed in patients with TSH > 30 U/L. The specific preparations available are: 1. Discontinuation of thyroxine (Euthyrox, Retis) or thyroid tablets for more than 2 weeks (children) – 3 weeks (adults); 2. Conversion to triiodothyronine (T3, imported) after discontinuation of thyroxine for 2-4 weeks and discontinuation for 2 weeks (commonly used in Europe and the US); 3. Injection of recombinant human thyrotropin ( rhTSH, trade name Thyrogen, for patients who cannot tolerate hypothyroidism and pituitary lesions that do not produce TSH) Note: thyroxine can be resumed 24-48 hours after taking iodine-131.