F-18 Tetrafluoroborate PET/CT in Differentiated Thyroid Cancer

In patients who have undergone surgery for differentiated thyroid cancer and who demonstrate elevated serum Tg and/or ATg levels during follow-up after radioactive iodine therapy, lesion detection is performed using neck ultrasonography, thorax CT, and F-18 FDG PET/CT. Diagnostic whole-body scanning with low-dose I-131 is not routinely recommended in follow-up due to its low sensitivity and specificity. F-18 TFB is a highly specific imaging agent for differentiated thyroid cancer, entering thyroid follicular epithelial cells via the sodium-iodide symporter (NIS), which is expressed on the cell surface and functions through a mechanism similar to that of I-131. As a PET radiotracer, F-18 TFB has been shown to be superior to I-131 in previous studies. The primary aim of this study is to comparatively evaluate the role of F-18 TFB PET/CT versus the standard imaging modality F-18 Fluorodeoxyglucose (FDG) PET/CT in lesion detection in patients with differentiated thyroid cancer who demonstrate elevated serum Tg and/or ATg levels during follow-up after radioactive iodine therapy. The secondary aims are to investigate the factors predicting F-18 TFB PET/CT positivity and to assess the relationship between the semi-quantitative and quantitative parameters derived from F-18 TFB PET/CT and serum thyroglobulin (Tg) and anti-thyroglobulin (ATg) levels.