Taking iodine, i.e. taking iodine 131 treatment. Generally 1 to 3 months after the treatment, a review is needed, mainly to draw blood to check Tg, TSH, T3, T4 and other indicators, plus neck ultrasound if necessary. The specific time for review should be determined according to individual circumstances. Review is required 1 to 3 months after taking iodine 131 treatment, which mainly involves blood sampling to check the changes in the levels of Tg, TSH, T3, T4 and other indexes, which can assess the treatment effect, adjust the dosage of medication in time, and add neck ultrasound if necessary, to review the changes in the suspected lymph nodes after treatment with iodine 131. If the patient has obvious symptoms of hypothyroidism such as drowsiness, fatigue, and fear of cold in a short period of time after taking iodine, the patient should be rechecked as soon as possible, which may suggest that the dosage of iodine 131 is too large, leading to hypothyroidism, and if necessary, oral levothyroxine substitution therapy should be taken. The specific time for review after taking Iodine 131 treatment should be determined according to one’s own situation, and if there are symptoms of discomfort, one should go to the hospital as soon as possible.