Hypoechoic thyroid nodules on ultrasound 4 years after prenatal exposure to radioiodine: resolution with thyroxine therapy.

Unlabelled: We describe an infant inadvertently exposed to radioiodine at 17 weeks gestation. His mother had received 400 MBq of (131)I for hyperthyroidism (total T4 178 nmol/L, thyroid stimulating hormone (TSH) <0.1 mU/L, 4-h (131)I uptake 16%).