Comparison of [18F] FDG PET/CT and [18F] FBPA PET/CT for diagnostic ability in the differential diagnosis of malignant tumors and benign lesions

Introduction: Objective: [¹⁸F] FDG PET/CT is used to diagnose malignant tumors by utilizing the strong glucose uptake of malignant tumor cells. However, since inflammatory cells also take up glucose, it is often difficult to differentiate malignant tumors from other lesions. Amino acid metabolism is also enhanced in malignant tumor cells, and it has been reported in basic research that [¹⁸F] FBPA, a boron compound of phenylalanine, an essential amino acid, labeled with F-18, selectively accumulates in malignant tumors. In this study, in order to evaluate the tumor-specific diagnostic ability of [¹⁸F] FBPA PET/CT, both [¹⁸F] FDG and [¹⁸F] FBPA PET/CT examinations were performed in patients with malignant tumors and inflammatory lesions, and compared them with pathological diagnosis.

Methods: Methods: A total of 76 patients (40 males and 36 females; median age, 64 years; age range, 20–89 years) with various types of malignancies and benign lesions such as inflammation and granulomas were examined by [¹⁸F] FBPA PET/CT and [¹⁸F] FDG PET/CT. Tumor uptake was quantified by measuring the maximum standardized uptake value (SUV max). The final diagnosis of the lesion was confirmed by the cytopathology or histopathological findings of the specimen after biopsy or resection. The ROC curve was constructed from the SUV max values of each PET image, and the area under the curve (AUC) and cutoff values were calculated. The sensitivity and specificity of [¹⁸F] FBPA and [¹⁸F] FDG PET/CT were determined, respectively.

Results: Results: The SUV max of [¹⁸F] FBPA PET/CT was 4.92 ± 2.67 for malignancies and 2.93 ± 0.57 for benign lesions, with a statistically significant difference between the two (P=0.001). Meanwhile, the SUV max of [¹⁸F] FDG PET/CT was 10.67 ± 6.26 for malignancies and 9.03 ± 2.82 for benign lesions, showing no statistically significant difference (P =0.63). The best SUV max cutoff (sensitivity 0.552, specificity 1.000) was 4.14 to distinguish between malignancies and benign lesions on [¹⁸F] FBPA PET/CT. On the other hand, the best SUV max cutoff for distinguishing malignancies from benign lesions by [¹⁸F] FDG PET/CT was 11.16 (sensitivity 0.900, specificity 0.373). There was a statistically significant difference between the two groups (P=0.003).

Conclusions: Conclusions: [¹⁸F] FBPA PET/CT showed a superior diagnostic ability over [¹⁸F] FDG PET/CT in the differential diagnosis of malignant tumors and benign lesions. The results of this study revealed that [¹⁸F] FBPA PET/CT diagnosis may reduce the need for invasive biopsy and resection for pathological definitive diagnosis.