Abstract: Background and purpose:  ¹⁸ F-prostate-specific membrane antigen (PSMA)-1007 PET/CT is an advanced imaging evaluation method for prostate cancer. The purpose of this study was to investigate the value of  ¹⁸ F-PSMA-1007 PET/CT in the accurate diagnosis of primary and metastatic foci in patients with newly diagnosed prostate cancer (PCa) and its impact on clinical treatment decisions. Methods: The clinical data of 18 newly diagnosed cases of prostate cancer who showed PSMA-positive lesions on  ¹⁸ F-PSMA-1007 images from November 2018 to February 2019 were retrospectively reviewed. Professional nuclear medicine physicians read the images in a blind manner. Radioactive uptake of tumors was calculated semi-quantitatively by region of interest method and expressed by the maximum standardized uptake value (SUV _max ). Diagnostic efficacy for primary and metastatic foci as well as its impact on clinical treatment decisions of  ¹⁸ F-PSMA-1007 PET/CT was evaluated, and the correlation between tumor uptake and PSA, Gleason score was further evaluated. Results:  ¹⁸ F-PSMA-1007 PET/CT accurately detected all 18 PCa patients, and the sensitivity, positive predictive value and accuracy were 100% respectively. Tumor tissues of PCa showed focal radioactivity uptake. No metastasis was found in 5 cases (27.8%), and metastasis was found in 13 cases (72.2%). Ten patients had positive finding n the lymph node metastasis (including 4 cases of simple pelvic lymph node metastasis and 6 cases of retroperitoneal extra-regional lymph node metastasis). There were 10 cases of bone metastasis and 3 cases of visceral (lung) metastasis, and 7 cases (38.9%) were PCa with high tumor load. The median SUV _max of 18 patients was 13.05. SUV _max of the PCa patients had no significant relation with PSA and Gleason Score (P＞0.05). In terms of clinical treatment decisions, except for 1 patient (with primary lung cancer) who gave up treatment, 8 patients changed the original treatment plan, and the change rate was 47.1% (8/17). Conclusion:  ¹⁸ F-PSMA-1007 PET/CT has good diagnostic value and efficiency for the detection of the primary and metastatic foci in PCa, which is conducive to accurate staging and individualized treatment, and significantly affects clinical treatment decisions.

Key words: Prostate specific membrane antigen, PET/CT, Prostate cancer, Early diagnosis