68Ga-FAPI PET/CT Versus 18F-FDG PET/CT for Detecting Metastatic Lesions in a Case of Radioiodine-Refractory Differentiated Thyroid Cancer

F-18-FDG PET/CT is a useful imaging modality for detecting disease recurrence and metastases in patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). However, the sensitivity of F-18-FDG PET/CT in RAIR-DTC is not very satisfactory. Ga-68-FAPI is a promising PET tracer that allowed imaging of various types of cancer. In this case, Ga-68-FAPI showed a far better signal-to-background ratio than F-18-FDG for detecting the RAIR-DTC metastatic lesions, especially for detecting the small pulmonary metastases. Therefore, Ga-68-FAPI may be a promising alternative to F-18-FDG for detecting tumor recurrence and metastases in RAIR-DTC. It could also be used for guiding FAP-targeted radionuclide therapy.

Automated summary

Ga-68-FAPI is a promising alternative to F-18-FDG for detecting tumor recurrence and metastases in patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC), showing a better signal-to-background ratio, especially for detecting small pulmonary metastases. It can also be used for guiding FAP-targeted radionuclide therapy.