Relation between severity of thyrotoxicosis and response to 131I therapy

The relation between the severity of hyperthyroidism and response to 131I therapy was tested in a group of 45 patients 6 to 12 months after therapy. At following treatment 7 patients were hypothyroid, 13 euthyroid and 25 hyperthyroid. The absolute iodine uptake and gland size was significantly higher in the hyperthyroid group compared with the other groups. The radiation dose was similar in the groups, but the ratio between dose and uptake was significantly lower in the hyperthyroid group.