Cross indicates the patient' suprasternal notch. (A) 24-hour thyroid radioactive iodine test revealed high uptake (57%; normal reference: 8%-32%) and a diffuse distribution, strengthening the diagnosis of Graves disease. (B) A 24-hour thyroid radioactive iodine test showed high uptake of 36% and a solitary “hot” thyroid nodule in the right lobe, supporting the diagnosis of solitary toxic thyroid nodule. (C) Thyroid ultrasound revealed 1 cystic-solid isoechoic nodule in the right lobe, measuring 1.8 × 1.0 × 0.9 cm, reinforcing the diagnosis of toxic thyroid nodule. (D) A 24-hour thyroid radioactive iodine scan after iodine-131 treatment with 1.11 MBq (30 mCi) showed a homogeneous diffuse thyroid distribution, demonstrating a successful treatment of the solitary toxic thyroid nodule.