Advancements in theranostic applications: exploring the role of fibroblast activation protein inhibition tracers in enhancing thyroid health assessment

Background The diagnostic accuracy of [^18F]-fluorodeoxyglucose ([^18F]-FDG) positron emission tomography imaging in accurately identifying thyroid lesions is limited, primarily due to the physiological uptake of normal head and neck tissues and inflammatory uptake in lymph nodes.

Since fibroblast activating protein is highly expressed in tumors and largely unexpressed in normal tissues, quinoline-based fibroblast activating protein inhibitors (FAPI) have emerged as promising tools in the diagnosis of cancer and other medical conditions.

Several studies have reported on the feasibility and value of FAPI in thyroid cancer.

Main body In this narrative review, we summarize the current literature on state-of-the-art FAPI positron emission tomography imaging for thyroid cancer and fibroblast activating protein-targeted radionuclide therapy.

We provide an overview of FAPI uptake in normal thyroid tissue, thyroid cancer and its metastases.

Additionally, we highlight the difference between FAPI uptake and [^18F]-FDG uptake in thyroid lesions.

Furthermore, we discuss the therapeutic value of FAPI in iodine-refractory thyroid cancer.

Conclusion The utilization of fibroblast activating protein inhibitors in thyroid cancer holds significant promise, offering clinicians valuable insights for more precise diagnose choices and treatments strategies in the future.