If a patient has an indication for nail clearing therapy but is found to have excess residual thyroid tissue during the pre-treatment evaluation, the patient should be advised to first undergo a re-excision of as much residual thyroid tissue as possible, otherwise the effectiveness of nail clearing is less likely to be guaranteed. Although nail clearing may remove residual thyroid lobes, it is not recommended as an alternative to surgery. If surgically resectable DTC metastases are identified during the evaluation prior to nail clearing, reoperation should be performed first. Direct thyroidectomy may be considered only if the patient has a contraindication to reoperation or refuses reoperation. For patients with poor general status, concomitant serious diseases or other high-risk malignancies, priority should be given to correction of general status and treatment of concomitant diseases before considering nail clearing treatment. In normal thyroid follicular epithelial cells and DTC cells, the sodiumiodidesymporter (NIS) is expressed in the cytosolic membrane and can fully uptake 131I when stimulated by TSH; therefore, it is necessary to raise the serum TSH level before nail cleansing therapy. Serum TSH >30mU/L significantly increases the uptake of 131I by DTC tumor tissue. Elevating TSH levels can be achieved in two ways: ① Elevating endogenous TSH levels: withholding L-T4 for 4-6 weeks after total/near-total thyroidectomy or (for those who have started TSH suppression therapy) discontinuing L-T4 for at least 2-3 weeks to allow serum TSH levels to rise above 30mU/L. ② Use of recombinant human TSH (rhTSH): intramuscular injection of rhTSH 0.9 mg daily for two days prior to nail clearing therapy, without discontinuing L-T4. rhTSH is particularly indicated for elderly DTC patients, those who cannot tolerate hypothyroidism, and those whose TSH elevation cannot reach the target after discontinuing L-T4. Currently, rhTSH has been approved for adjuvant nail cleansing therapy in many countries in Europe, the United States, Asia, and Hong Kong and Taiwan in China, but this drug has not yet been registered for marketing in mainland China. Diagnostic whole-body nuclide imaging (Dx-WBS) can be performed prior to nail clearing treatment to: (1) assist in understanding the presence of iodine-intake metastases; (2) assist in calculating the dose of 131I therapy; and (3) predict the impact of iodine load on nail clearing therapy. However, it has also been suggested that Dx-WBS is not necessary prior to nail clearing because the low dose of 131I used in Dx-WBS is almost entirely taken up by residual thyroid tissue, which does not effectively demonstrate iodine uptake metastases and may cause “stuttering”. “Stunning” means that the low dose 131I used for diagnostic purposes reduces the uptake of normal thyroid tissue and iodine uptake metastases to the high dose 131I subsequently used for treatment. Ways to reduce “stuttering” include: using low-dose 131I (<5mCi) and administering nail clearance within 72 hours of diagnostic dosing; replacing 131I with 123I as the diagnostic agent for DxWBS, but 123I is difficult and expensive to source. The efficacy of 131I is dependent on the dose of 131I entering the residual thyroid tissue and within the DTC lesion. Stable iodine ions in the body compete with 131I to enter the thyroid tissue and DTC lesions, so patients are required to be on a low iodine diet (<50 μg/d) for at least 1-2 weeks prior to 131I nail clearing treatment. Iodine-containing contrast agents and medications (e.g., amiodarone) must be avoided during the treatment waiting period. If iodine-containing contrast agents or foods or medications containing high doses of iodine have been used prior to nail clearing treatment, treatment should be withheld. Urinary iodine levels can be monitored when available. Pregnancy testing is required for women of childbearing age prior to the administration of nail clearing treatment. In addition, the patient should be informed about the purpose of the treatment, the implementation process, possible side effects after the treatment, etc., and be instructed on radiation safety protection.