Li_2024_Cancer.Biother.Radiopharm_39_654

Objectives: We compared the value of the semiquantitative parameters of (68)Ga-labeled FAP inhibitor ((68)Ga-FAPI)-04 positron emission tomography/computed tomography (PET/CT) and (18)F-fluorodeoxyglucose ((18)F-FDG) in diagnosing primary malignant and benign diseases. Materials and Methods: (18)F-FDG and (68)Ga-FAPI-04 PET/CT images of 80 patients were compared. Semiquantitative parameters, including maximum standardized uptake value (SUV(max)), mean SUV (SUV(mean)), peak SUV (SUV(peak)), peak SUV by lean body mass (SUL(peak)), metabolic tumor volume (or tumor volume of FAPI; FAPI-TV), and TLG (or total lesion activity of FAPI; FAPI-TLA), were automatically obtained using the IntelliSpace Portal image processing workstation with a threshold of 40% SUV(max). The liver blood pool was measured as the background, and the tumor-to-background ratio (TBRliver) was calculated. Results: In all malignant lesions, FAPI-TV and FAPI-TLA were higher in (68)Ga-FAPI-04 PET/CT than in (18)F-FDG. In the subgroup analysis, (68)Ga-FAPI-04 had higher FAPI-TV and FAPI-TLA and lower SUV(max) than (18)F-FDG had in group A, including gynecological tumor, esophageal, and colorectal cancers. However, six semiquantitative parameters were higher in group B (the other malignant tumors). For the benign diseases, SUV(max), SUV(mean), SUV(peak), and SUL(peak) were lower in (68)Ga-FAPI-04 PET/CT than in (18)F-FDG. (68)Ga-FAPI-04 PET/CT showed a lower liver background and a higher TBRliver than (18)F-FDG did. (68)Ga-FAPI-04 PET/CT had higher accuracy, sensitivity, and specificity than (18)F-FDG had. Conclusion: More accurate semiquantitative parameters and lower abdominal background in (68)Ga-FAPI-04 PET/CT make it more competitive in the differential diagnosis of malignant and benign diseases than in (18)F-FDG.