“…Factors that predict failure [21] include young age, large glands, higher levels T4 or T3 at diagnosis, very high radioiodine uptake [30]. Generally, the prescribed dose should be higher when a euthyroid state is required in a short time [31], thyroidal uptake is very high [30] or heterogeneous uptake from nodular thyroid disease, toxic adenoma and toxic multinodular goiter (Fig. 1).…”