Comparison of [ 68 Ga]Ga-DOTA-FAPI-04 and [ 18 F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer.

Purpose: We evaluated the potential usefulness of [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) for the diagnosis of primary and metastatic lesions in various types of cancer, compared with [ ¹⁸ F] FDG PET/CT.
Methods: A total of 75 patients with various types of cancer underwent contemporaneous [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 and [ ¹⁸ F] FDG PET/CT either for an initial assessment or for recurrence detection. Tumour uptake was quantified by the maximum standard uptake value (SUV _max ). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of [ ¹⁸ F] FDG and [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 PET/CT were calculated and compared to evaluate the diagnostic efficacy.
Results: The study cohort consisted of 75 patients (47 males and 28 females; median age, 61.5 years; age range, 32-85 years). Fifty-four patients with 12 different tumour entities underwent paired [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 and [ ¹⁸ F] FDG PET/CT for initial assessment, while the other 21 patients underwent paired scans for recurrence detection. [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 PET/CT was able to clearly identify 12 types of malignant tumours with favourable tumour-to-background contrast, which resulted in a higher detection rate of primary tumours than did [ ¹⁸ F] FDG PET/CT (98.2% vs. 82.1%, P = 0.021). Meanwhile, [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 PET/CT showed a better sensitivity than [ ¹⁸ F] FDG PET/CT in the detection of lymph nodes (86.4% vs. 45.5%, P = 0.004) and bone and visceral metastases (83.8% vs. 59.5%, P = 0.004).
Conclusion: [ ⁶⁸ Ga]Ga-DOTA-FAPI-04 PET/CT showed a superior diagnostic efficacy than [ ¹⁸ F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer, especially in identifying liver metastases, peritoneal carcinomatosis, and brain tumours.