FAPI is a fibroblast activation protein inhibitor and 68Ga-FAPI-04 is a potential new imaging agent for imaging of carcinoma. 68Ga-FAPI-04 PET/CT is helpful to clarify the benign, malignant and invasive range of the oral carcinoma, locate and qualitatively diagnose the tumor, and make early diagnosis and restaging of recurrent tumor.

Sometimes, the traditional 18F-FDG PET/CT diagnosis of head and neck tumors mistakenly diagnosed inflammatory lymph nodes as metastatic lymph nodes, resulting in false positive results. Fibroblast activation protein (FAP) is a serine peptidase on the surface of tumor associated fibroblasts. It plays an important role in promoting the growth, invasion, metastasis and immunosuppression of tumor cells. FAPI is a fibroblast activation protein inhibitor and 68Ga-FAPI-04 is a potential new imaging agent for imaging of carcinoma. 68Ga-FAPI-04 PET/CT is helpful to clarify the benign, malignant and invasive range of the oral carcinoma, locate and qualitatively diagnose the tumor, and make early diagnosis and restaging of recurrent tumor.

Inclusion Criteria:

• patients in suspicion of oral carcinoma,
• 68Ga-FAPI-04 and 18F-FDG PET/CT within 2 week;
• being able to provide basic information and sign the written informed consent form.

Exclusion Criteria:

• claustrophobia,
• pregnancy,
• breastfeeding,
• kidney or liver failure,
• inability to fulfill the study.