The following preparations should be made in advance for the treatment of hyperthyroidism with radioactive iodine: 1. Avoid iodine and other iodine-containing foods or drugs for 2 to 4 weeks prior to oral iodine-131 treatment. 2. If the condition is severe before iodine-131 treatment, with heart rate exceeding 160 beats per minute, or if the condition is severe, it is advisable to first treat with anti-thyroid drugs or insulin, etc., and then use iodine-131 treatment only when the symptoms have been reduced. 3. Patients using antithyroid drugs generally need to stop taking them, methimazole for about 2-7 days, and propylthiouracil for 2-4 weeks, then the iodine-131 uptake rate can be measured, followed by iodine-131 treatment. 4. On the day of treatment, the following basic tests should be performed: serum FT3, FT4 and TSH measurement, thyroid uptake rate, blood count, liver and kidney function, electrocardiogram, thyroid nuclear imaging and/or thyroid ultrasound. 5. Women of childbearing age should pay attention to exclude pregnancy.