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Prostate-specific membrane antigen [4_TD$DIFF]Positron-emission tomography Prostate cancer Prostate-specific membrane antigen (PSMA) overexpression theoretically enables tar-geting of prostate cancer (PCa) metastases using gallium Ga 68 (68Ga)–labeled PSMA ligands for positron emission tomography/computed tomography (PET/CT) imaging. Promising detection rates have been reported when using this approach for functional imaging of recurrent PCa; however, until now, the diagnostic accuracy of 68Ga-PSMA PET/CT for preoperatively identifying lymph node metastases (LNMs) had not been assessed. We retrospectively compared preoperative 68Ga-PSMA PET/CT lymph node (LN) findings with histologic work-up after radical prostatectomy (RP). Overall, 608 LNs containing 53 LNMs were detected during RP. LNMs were present in 12 of 30 patients (40%). The 68Ga-PSMA PET/CT scans identified 4 patients (33.3%) as LN true positive and 8 patients (66.7%) as false negative. Median size of 68Ga-PSMA-PET/CT–detected versus undetected LNMs was 13.6 versus 4.3 mm (p < 0.05). Overall sensitivity, specificity, positive predictive value, and negative predictive value of 68Ga-PSMA PET/CT for LNM risk prostate cancer patients prior to radical prostatectomy. We found that lymph nodeE-mail address: budaeuPlease visit www.eu-acme.org/ europeanurology to read and answer questions on-line. The EU-ACME credits will then be attributed automatically. metastasis detection rates were substantially influenced by lymph nodemetastasis size