Applications of 131 iodine thyroid imaging for thyroid cancer: (a) After total thyroidectomy for thyroid cancer and before preparing for clear nail treatment with 131 iodine, 131 iodine thyroid imaging can evaluate the situation of residual thyroid tissue and whether there is distant metastasis, which can be used as the basis of efficacy evaluation after clear nail treatment. (b) Whole body scan after 131 iodine treatment for thyroid cancer is to observe the residual thyroid gland and distant metastasis under the tracer of high dose 131 iodine. (c) Whole-body scan before 131 iodine treatment again is to observe the effect of the last 131 iodine treatment and provide the basis of indications for 131 iodine treatment again. (iv) Whole-body scan is an important examination method in the follow-up of nail cancer. Summary: Significance of 131 iodine whole body scan After thyroid cancer surgery It can evaluate the disease. After 131 iodine treatment for thyroid cancer It can evaluate the results of high-dose 131 iodine scan Before 131 iodine treatment again for thyroid cancer It can evaluate the effect of the last 131 iodine treatment Provide the indication for 131 iodine treatment again It can evaluate the disease in the follow-up of thyroid cancer