[¹⁸F]FDG PET/CT snapshot of radioactive iodine–induced thyroid damage

Excerpt

A 39-year-old female with metastatic breast cancer was referred to [¹⁸F]FDG PET/CT for treatment response assessment (hormonal therapy). Simultaneously, for the last few years, she suffered from symptomatic hyperthyroidism (TSH < 0.01 μIU/ml, FT4 = 23 PMOL/L, FT3 = 8 PMOL/L) with partial response to anti-thyroid therapy. Thyroid scintigraphy using ^99mTcO4^- suggested the etiology of Graves’ disease. Prior to definitive treatment, radioiodine uptake test (RAIU) was performed and revealed high uptake levels of RAI as expected. After appropriate preparation, the patient was treated with 15 mCi of RAI. Three months later, she was referred to the PET/CT mentioned above, at the time she was euthyroid (TSH = 0.9 μIU/ml, FT4 = 8.2 PMOL/L, FT3 = 2.7 PMOL/L). …