RT Journal Article SR Electronic T1 Initial Evaluation of [18F]FAPI-74 PET for Various Histopathologically Confirmed Cancers and Benign Lesions JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1225 OP 1231 DO 10.2967/jnumed.123.265486 VO 64 IS 8 A1 Watabe, Tadashi A1 Naka, Sadahiro A1 Tatsumi, Mitsuaki A1 Kamiya, Takashi A1 Kimura, Toru A1 Shintani, Yasushi A1 Abe, Kaori A1 Miyake, Tomohiro A1 Shimazu, Kenzo A1 Kobayashi, Shogo A1 Kurokawa, Yukinori A1 Eguchi, Hidetoshi A1 Doki, Yuichiro A1 Inohara, Hidenori A1 Kato, Hiroki A1 Mori, Yuriko A1 Cardinale, Jens A1 Giesel, Frederik L. YR 2023 UL http://jnm.snmjournals.org/content/64/8/1225.abstract AB The 18F-labeled fibroblast activation protein inhibitor (FAPI) [18F]FAPI-74 has the benefit of a higher synthetic yield and better image resolution than 68Ga-labeled FAPI. We preliminarily evaluated the diagnostic performance of [18F]FAPI-74 PET in patients with various histopathologically confirmed cancers or suspected malignancies. Methods: We enrolled 31 patients (17 men and 14 women) with lung cancer (n = 7), breast cancer (n = 5), gastric cancer (n = 5), pancreatic cancer (n = 3), other cancers (n = 5), and benign tumors (n = 6). Twenty-seven of the 31 patients were treatment-naïve or preoperative, whereas recurrence was suspected in the remaining 4 patients. Histopathologic confirmation was obtained for the primary lesions of 29 of the 31 patients. In the remaining 2 patients, the final diagnosis was based on the clinical course. [18F]FAPI-74 PET scanning was performed 60 min after the intravenous injection of [18F]FAPI-74 (240 ± 31 MBq). The [18F]FAPI-74 PET images were compared between the primary or local recurrent lesions of malignant tumors (n = 21) and nonmalignant lesions (n = 8: type-B1 thymomas, granuloma, solitary fibrous tumor, and postoperative or posttherapeutic changes). The uptake and number of detected lesions on [18F]FAPI-74 PET were also compared with those on [18F]FDG PET for available patients (n = 19). Results: [18F]FAPI-74 PET showed higher uptake in primary lesions of various cancers than in nonmalignant lesions (median SUVmax, 9.39 [range, 1.83–25.28] vs. 3.49 [range, 2.21–15.58]; P = 0.053), but some of the nonmalignant lesions showed high uptake. [18F]FAPI-74 PET also showed significantly higher uptake than [18F]FDG PET (median SUVmax, 9.44 [range, 2.50–25.28] vs. 5.45 [range, 1.22–15.06] in primary lesions [P = 0.010], 8.86 [range, 3.51–23.33] vs. 3.84 [range, 1.01–9.75] in lymph node metastases [P = 0.002], and 6.39 [range, 0.55–12.78] vs. 1.88 [range, 0.73–8.35] in other metastases [P = 0.046], respectively). In 6 patients, [18F]FAPI-74 PET detected more metastatic lesions than [18F]FDG PET. Conclusion: [18F]FAPI-74 PET showed higher uptake and detection rates in primary and metastatic lesions than did [18F]FDG PET. [18F]FAPI-74 PET is a promising novel diagnostic modality for various tumors, especially for precise staging before treatment, including characterization of tumor lesions before surgery. Moreover, 18F-labeled FAPI ligand might serve a higher demand in clinical care in the future.