Purpose To report the results of dual-time-point gallium 68 (Ga) prostate-specific membrane antigen (PSMA)-11 positron emission tomography (PET)/magnetic resonance (MR) imaging prior to prostatectomy in patients with intermediate- or high-risk cancer. Materials and Methods Thirty-three men who underwent conventional imaging as clinically indicated and who were scheduled for radical prostatectomy with pelvic lymph node dissection were recruited for this study. A mean dose of 4.1 mCi ± 0.7 (151.7 MBq ± 25.9) of Ga-PSMA-11 was administered. Whole-body images were acquired starting 41-61 minutes after injection by using a GE SIGNA PET/MR imaging unit, followed by an additional pelvic PET/MR imaging acquisition at 87-125 minutes after injection. PET/MR imaging findings were compared with findings at multiparametric MR imaging (including diffusion-weighted imaging, T2-weighted imaging, and dynamic contrast material-enhanced imaging) and were correlated with results of final whole-mount pathologic examination and pelvic nodal dissection to yield sensitivity and specificity. Dual-time-point metabolic parameters (eg, maximum standardized uptake value [SUV]) were compared by using a paired t test and were correlated with clinical and histopathologic variables including prostate-specific antigen level, Gleason score, and tumor volume. Results Prostate cancer was seen at Ga-PSMA-11 PET in all 33 patients, whereas multiparametric MR imaging depicted Prostate Imaging Reporting and Data System (PI-RADS) 4 or 5 lesions in 26 patients and PI-RADS 3 lesions in four patients. Focal uptake was seen in the pelvic lymph nodes in five patients. Pathologic examination confirmed prostate cancer in all patients, as well as nodal metastasis in three. All patients with normal pelvic nodes in PET/MR imaging had no metastases at pathologic examination. The accumulation ofGa-PSMA-11 increased at later acquisition times, with higher mean SUV (15.3 vs 12.3, P < .001). One additional prostate cancer was identified only at delayed imaging. Conclusion This study found that Ga-PSMA-11 PET can be used to identify prostate cancer, while MR imaging provides detailed anatomic guidance. Hence,Ga-PSMA-11 PET/MR imaging provides valuable diagnostic information and may inform the need for and extent of pelvic node dissection.

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18 F-DCFPyL (2-(3-{1-carboxy-5-[(6-18 F-fluoropyridine-3-carbonyl)amino]-pentyl}-ureido)-pentanedioic acid) is a promising PET radiopharmaceutical targeting prostate-specific membrane antigen (PSMA). We present our experience with this single-academic-center prospective study evaluating the positivity rate of 18 F-DCFPyL PET/CT in patients with biochemical recurrence (BCR) of prostate cancer (PC). Methods: We prospectively enrolled 72 men (52-91 y old; mean ± SD, 71.5 ± 7.2) with BCR after primary definitive treatment with prostatectomy (n 5 42) or radiotherapy (n 5 30). The presence of lesions compatible with PC was evaluated by 2 independent readers. Fifty-nine patients had scans concurrent with at least one other conventional scan: bone scanning (24), CT (21), MR (20), 18 F-fluciclovine PET/CT (18), or 18 F-NaF PET (14). Findings from 18 F-DCFPyL PET/CT were compared with those from other modalities. Impact on patient management based on 18 F-DCFPyL PET/CT was recorded from clinical chart review. Results: 18 F-DCFPyL PET/CT had an overall positivity rate of 85%, which increased with higher prostate-specific antigen (PSA) levels (ng/mL): 50% (PSA , 0.5), 69% (0.5 # PSA , 1), 100% (1 # PSA , 2), 91% (2 # PSA , 5), and 96% (PSA $ 5). 18 F-DCFPyL PET detected more lesions than conventional imaging. For anatomic imaging, 20 of 41 (49%) CT or MRI scans had findings congruent with 18 F-DCFPyL, whereas 18 F-DCFPyL PET was positive in 17 of 41 (41%) cases with negative CT or MRI findings. For bone imaging, 26 of 38 (68%) bone or 18 F-NaF PET scans were congruent with 18 F-DCFPyL PET, whereas 18 F-DCFPyL PET localized bone lesions in 8 of 38 (21%) patients with negative results on bone or 18 F-NaF PET scans. In 8 of 18 (44%) patients, 18 F-fluciclovine PET had located the same lesions as did 18 F-DCFPyL PET, whereas 5 of 18 (28%) patients with negative 18 F-fluciclovine findings had positive 18 F-DCFPyL PET findings and 1 of 18 (6%) patients with negative 18 F-DCFPyL findings had uptake in the prostate bed on 18 F-fluciclovine PET. In the remaining 4 of 18 (22%) patients, 18 F-DCFPyL and 18 F-fluciclovine scans showed different lesions. Lastly, 43 of 72 (60%) patients had treatment changes after 18 F-DCFPyL PET and, most noticeably, 17 of these patients (24% total) had lesion localization only on 18 F-DCFPyL PET, despite negative results on conventional imaging. Conclusion: 18 F-DCFPyL PET/CT is a promising diagnostic tool in the work-up of biochemically recurrent PC, given the high positivity rate as compared with Food and Drug Administration-approved currently available imaging modalities and its impact on clinical management in 60% of patients.