Comparison of Different Thyroid Committed Doses in Radioiodine Therapy for Graves' Hyperthyroidism

Despite vast worldwide experience in the use of 131I for treating Graves' disease (GD), no consensus of opinion exists concerning the optimal method of dose calculation. In one of the most popular equations, the administered 131I dose is directly proportional to the estimated thyroid gland volume and inversely proportional to the measured 24-hour radioiodine uptake. In this study, we compared the efficiency of different tissue-absorbed doses to induce euthyroidism or hypothyroidism within 1 year after radioiodine therapy in GD patients. The study was carried out in 134 GD patients (age, 53 ± 14 year; range, 16–82 year; thyroid volume, 28 ± 18 mL; range, 6–95 mL; average 24-hour thyroid uptake, 72%) treated with 131I therapy. The average radioiodine activity administered to patients was 518 ± 226 MBq (range, 111–1110). The corresponding average thyroid absorbed dose, calculated by a modified Medical Internal Radiation Dose (MIRD) equation was 376 ± 258 Gy (range, 99–1683). One year after treatment, 58 pati...