Changes in thyroid volume after radioactive iodine therapy in patients with single toxic thyroid nodule

: Radioactive iodine (131I) is a well-established therapeutic modality in the treatment of toxic solitary autonomous thyroid nodules. This method is preferred in patients with small, benign nodules. The aim of our study was to investigate the effects of radioiodine therapy on thyroid size in patients with a solitary toxic thyroid nodule. 22 patients with single nodule in USG and confirmed "hot" nodule in scintigraphy were enrolled in the study. Thyroid and nodule volume were determined by ultrasound before, 3 and 6 months after the administration of 131I. Thyroid function was assessed by TSH level prior to the treatment and 6 weeks after the therapy. Thyroid volume and nodule size decreased significantly within 3 and 6 months after 131I treatment. The mean reduction of thyroid volume within 6 month after treatment was 32%. Reduction in thyroid volume and nodule, size was significantly greater within first 3 months than within next 3 months. Patients with smaller nodules (less than 70% of thyroid volume) were characterized by greater reduction of goiter size than patients with nodules bigger or equal to 70% of thyroid volume.