RESUMEN
This study was carried out on 20 patients with hyperthyroidism. The diagnosis was based on clinical, laboratory, isotopic study and thyroid scan. Thyroid scanning was done at two stages; one before radioactive iodine therapy and one 6 months after treatment. Thyroid scintigraphy before treatment revealed that 16 patients had Gravs' disease [80%] and four patients had toxic nodular goiter [20%]; two patients had hot nodules and two had toxic multinodular goiter. It was useful for calculating the dose of radioactive iodine as it helps in estimation of gland size. After treatment 19 patients showed normal trace uptake accumulation, while one patient still had an increase trace uptake indicating persistent hyperthyroid scintigraphic picture and this was confirmed by clinical manifestations and laboratory tests. Two patients with normal trace uptake had hypothyroid manifestations as confirmed by clinical and laboratory findings. Accordingly, our conclusion is that thyroid scintigraphy is a helpful tool for diagnosis, verification of the type of hyperthyroidism and for estimation of the therapeutic dose of radioactive iodine but not for follow up after treatment