Imaging and blood tests should be done six months after thyroidectomy. There are several indicators that need to be rechecked, such as thyroid function, and you should return to the hospital for regular rechecks as prescribed by your doctor. 1. Imaging examination: including thyroid ultrasound, chest CT or MRI examination. (1) Thyroid ultrasound: the first postoperative ultrasound is recommended to be performed 3 months after surgery. (2) Chest CT or MRI: CT or MRI is not a routine examination in the follow-up after thyroidectomy, but chest CT or MRI is needed when there is lymph node recurrence but ultrasound cannot accurately describe the range, metastatic lesions invade the upper respiratory tract, or thyroglobulin is elevated in high-risk patients. 2. Blood test: including thyroid function test, thyroglobulin test, thyroid autoantibody test, calcitonin and carcinoembryonic antigen test. (1) Thyroid function test: It is recommended that this test be performed 1 month after surgery to decide whether to adjust the dose of medication. (2) Thyroglobulin test: Patients with total thyroidectomy should be tested for thyroglobulin periodically to see if the cancer has returned. (3) Thyroid autoantibody test: Thyroid autoantibodies affect the level of thyroglobulin, so it is necessary to check thyroid autoantibodies at the same time as the thyroglobulin test. (4) Calcitonin and carcinoembryonic antigen test: Calcitonin and carcinoembryonic antigen tests are helpful for efficacy evaluation and condition monitoring of medullary carcinoma patients. In addition to the medication prescribed by the doctor, patients should return to the hospital for regular checkups after thyroid surgery.