According to our clinical experience, even if you get the most brilliant surgeon to perform a total thyroidectomy, it is not possible to completely remove the thyroid tissue and more or less residual foci are found during the thyroid scan. And sometimes the surgery purposely preserves very few thyroid tissues in order to protect the parathyroid glands and the recurrent laryngeal nerve. Besides, there are some thyroid tissues and tiny metastases that cannot be found by the naked eye during the surgery, all these deserters may secretly lurk and are the breeding ground for tumor recurrence in the future, and once the time is ripe, they will counterattack the mainland. Moreover, due to the existence of remnant nail, he can also produce Tg like tumor, making it difficult to distinguish male from female in the later stage of disease monitoring and generating difficulties, and once recurrence occurs, it is extremely difficult to handle. Therefore, iodine 131 is needed to cut off the root after total thyroidectomy to help the surgery achieve a perfect thyroidectomy and at the same time facilitate the detection of the enemy and its timely elimination. Generally speaking, the earlier the postoperative thyroidectomy is cleared, the higher the tsh level, the higher the success rate. We generally recommend rest and recuperation, after the incision has healed, stop using eugenol for about 3 weeks, and tsh is greater than 30,then you can proceed to nail clearing treatment. After that, you can monitor and control the disease well through eugenol suppression therapy and tg tgab testing, so that everything is within the controllable range, so that you can know yourself and your enemy and never lose a battle, and really let the tumor go away. Also note that before taking iodine in the recent four weeks, do not strengthen ct and binge on seafood, otherwise the internal war with iodine 131 will affect the external war of resistance. It is a good idea to take the tasteless medicine once orally and get a high quality of life.