Thyroid cancer usually requires one or two nail-cleaning treatments, which means removing the residual thyroid tissue after thyroid cancer surgery. After thyroid cancer surgery, nail clearance treatment is usually needed to reduce the chance of recurrence of thyroid cancer, and iodine-131 is usually used for nail clearance treatment. Depending on the specific conditions of the patients, the number of times of nail cleaning is also different. 1. If the patient does not have lymph node metastasis or distant organ metastasis, one treatment is usually carried out, and the second one is not necessary, which is commonly known as the nail clearance treatment. 2. If the patient has extensive lymph node metastasis or distant organ metastasis, two treatments are usually needed, based on the first nail removal treatment, the second metastatic lesion treatment, also known as focal treatment. It is recommended to review the CT regularly, and the doctor will adjust the treatment plan in time according to the CT result, or more times of treatment may be needed to avoid delaying the condition.