TSHR and hyperthyroidism: Contraindications for RAI are (1) pregnancy and lactation, (2) GD with a nodular goiter and suspicion of thyroid cancer, (3) the presence of active GO, and (4) patients with an acknowledged high risk for the development and exacerbation of GO, for example, high stimulatory TSH-R-Ab, severe hyperthyroidism with high serum T3 levels, and smokers (1-3, 14).