A randomized open-labelled controlled prospective study to investigate the effect of inactive iodine and lithium carbonate on radioiodine therapy in patients with Graves' disease

INTERVENTION: Only radioiodine therapy Radioiodine therapy and inactive iodine 0.1 mg tid for 5 days Radioiodine therapy and lithium carbonate 600 mg tid for 8 days CONDITION: Graves' disease PRIMARY OUTCOME: Proportion of patients who achieved an euthyroid or hypothyroid at 24 weeks after radioiodine therapy : free T4 level of less than upper limit of normal SECONDARY OUTCOME: Proportion of patients who achieved an euthyroid or hypothyroid at 24 weeks after radioiodine therapy : free T3 level of less than upper limit of normal and TSH level of more than lower limit of normal. ; ; Changes in thyroid volume from 0 to 1 and 24 weeks.; ; Incidence and evaluation of adverse events INCLUSION CRITERIA: Graves' disease according to the guideline of the Japan Thyroid Association Patient who hoped for radioiodine treatment after enough explanation about risk and benefit of this therapy. Age>=19 years old when the consent is obtained. Possible to attend a hospital regularly about 24 weeks. No previous radioiodine therapy. Possible to obtain written informed consent.