(a) Patients with known distant metastases and extra-thyroidal invasion visible to the naked eye should be treated with 131 iodine regardless of the size of the tumor. Primary tumors >40mm in diameter without other risk factors should also be considered for 131 iodine therapy. (b) Intra-thyroidal tumors of 1-40 mm with lymph node metastasis or other high-risk factors should be considered for 131 iodine therapy if the patient’s age, tumor size, lymph node status, and tumor histologic type suggest a moderate to high recurrence and mortality rate. (c) For those with a single lesion, <10 mm in diameter and no other high-risk factors. Radiation 131 iodine therapy is not recommended for patients. (d) 131 iodine therapy is not recommended for those with multiple lesions, but all lesions are <10 mm in diameter and there are no other high-risk factors.