Objective: This study aimed to compare the diagnostic performance of 68 Ga-FAPI-04 and 18 F-FDG PET/CT in the patients with various oncological and non-oncological lesions.Patients and Methods: A total of 123 patients underwent contemporaneous 68 Ga-FAPI-04 and 18 F-FDG PET/CT were included in this prospective study. The maximum standard uptake value (SUVmax) was measured to compare oncological and non-oncological lesion uptake. The sensitivity, speci city, predictive values and accuracy of 18 F-FDG and 68 Ga-FAPI-04 PET/CT for detecting primary, metastatic, and non-oncological lesions were calculated and compared to evaluate the diagnostic e cacy.Results: The study subjects consisted of 123 patients (69 men and 54 women; mean age: 56.11±11.94). A total of 84 patients with 88 solid primary malignant tumors, 58 patients with 376 nodal metastases, 43 patients with 406 distant metastases, 8 patients with hematological neoplasms and 52 patients with 145 non-oncological lesions and benign tumors were detected. 68 Ga-FAPI-04 PET/CT demonstrated a signi cantly higher uptake and detection rate for the primary (SUVmax: 10.98±5.83 vs. 8.36±6.43, p 0.001; X 2 =0.538, p=0.021), nodal (SUVmax: 10.50±5.98 vs. 8.20±6.29, p=0.011; X 2 =2.067, p 0.001) and distant metastatic lesions (SUVmax: 6.74±4.83 vs. 9.64±6.45; p 0.001; X 2 =4.897, p 0.001) of solid tumor than did 18 F-FDG PET/CT. 68 Ga-FAPI-04 PET/CT demonstrated a lower activity (SUVmax: 6.84±4.67 vs. 13.09±7.29, p 0.001) and detection rate (X 2 =5.166, p 0.001) for multiple myeloma and lymphoma compared to 18 F-FDG PET/CT. 68 Ga-FAPI-04 and 18 F-FDG PET/CT PET/CT demonstrated a comparative diagnostic e cacy (SUVmax: 6.40±3.95 vs. 5.74±15.78, p = 0.729; X 2 = 9.460, p = 0.007) for nononcological lesion and benign tumor detection.Conclusions: Except for myeloma and lymphoma, 68 Ga-FAPI-04 PET/CT showed a superior diagnostic e cacy for detecting various primary and metastatic lesions than 18 F-FDG PET/CT. A comparative diagnostic utility for nononcological lesion detection was obtained with both tracers. 68 Ga-FAPI-04 could be used as a broad-spectrum tumor and in ammatory imaging agent in the clinical especially for various solid tumors and non-oncological lesions.

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We presented a case of 67-year-old man with epigastric discomfort and anorexia for more than 2 months. No abnormal 18 F-FDG uptake was found throughout the gastrointestinal tract on 18 F-FDG PET/CT. The patient was enrolled in the 68 Ga-FAPI PET/CT clinical trial, and a 68 Ga-FAPI PET/CT was performed to help detect primary lesion. This examination demonstrated a nodular thickening of the gastric wall with an increased 68 Ga-FAPI uptake in the greater curvature of the stomach. Finally, the pathological result confirmed the diagnosis of gastric stromal tumor. This case highlights that 68 Ga-FAPI PET/CT might outperform 18 F-FDG PET/CT in helping identify gastrointestinal stromal tumors.

We presented a 20-year-old woman with gradually increasing lethargy and multiple episodes of dizziness for 5 months. The laboratory examination revealed decreasing level of blood glucose and elevated levels of fasting plasma insulin and C-peptide. The MRI identified a focal nodule in the tail of the pancreas. 68Ga–DOTA–exendin-4 PET/CT revealed 2 intense focal tracer uptakes in the tail of the pancreas, one of which corresponded to the lesion revealed on MRI. The immunohistochemical results of resected samples confirmed the diagnosis of double-primary insulinomas. 68Ga–DOTA–exendin-4 PET/CT demonstrated excellent localization and characterization for double-primary insulinomas in the tail of the pancreas.