For postoperative patients, the presence of surrounding tissue invasion, lymph node metastasis, distant metastasis and the patient’s will should be comprehensively evaluated according to the pathological results, and whether to perform nail clearing treatment should be determined according to the evaluation results. For patients with obvious invasion of surrounding tissues (visible intraoperatively), lymph node metastasis or distant metastasis (such as lung, bone, brain and other organs), 131I nail clearing treatment should be performed. However, if the thyroid tissue has been completely excised, 131I nail clearing treatment can be performed for the convenience of follow-up. After the residual thyroid tissue has been removed, the recurrence and metastasis of DTC can be understood by testing Tg and 131I WBS during the follow-up. This will simplify the follow-up examination. Contraindications to 131I therapy: (1) women during pregnancy and lactation; (2) those who plan to be pregnant within 6 months. Note: WBS: whole body scan. 131I: iodine 131