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Figure 4.  Toxic multinodular goiter in a 71-year-old man with anxiety and weight loss. Laboratory values were as follows: T4 = 12.1 µg/dL, T3 = 299 ng/dL, and TSH < 0.01 µIU/mL. The RAIU was 17% at 6 hours and 37% at 24 hours. Anterior close-up I-123 image shows an enlarged thyroid with overall nonuniform uptake. Areas of both increased and decreased activity are scattered throughout the gland; the increased uptake represents hot nodules, whereas the decreased uptake represents a combination of suppressed extranodular tissue and cold thyroid nodules.