Purpose Since the introduction of positron emission tomography (PET) imaging with ⁶⁸Ga-PSMA-HBED-CC (=⁶⁸Ga-DKFZ-PSMA-11), this method has been regarded as a significant step forward in the diagnosis of recurrent prostate cancer (PCa). However, published data exist for small patient cohorts only. The aim of this evaluation was to analyse the diagnostic value of ⁶⁸Ga-PSMA-ligand PET/CT in a large cohort and the influence of several possibly interacting variables. Methods We performed a retrospective analysis in 319 patients who underwent ⁶⁸Ga-PSMA-ligand PET/CT from 2011 to 2014. Potential influences of several factors such as prostate-specific antigen (PSA) level and doubling time (DT), Gleason score (GSC), androgen deprivation therapy (ADT), age and amount of injected tracer were evaluated. Histological verification was performed in 42 patients after the ⁶⁸Ga-PSMA-ligand PET/CT. Tracer uptake was measured in 901 representative tumour lesions. Results In 82.8 % of the patients at least one lesion indicative of PCa was detected. Tumor-detection was positively associated with PSA level and ADT. GSC and PSA-DT were not associated with tumor-detection. The average maximum standardized uptake value (SUV_max) of tumour lesions was 13.3 ± 14.6 (0.7–122.5). Amongst lesions investigated by histology, 30 were false-negative in 4 different patients, and all other lesions (n = 416) were true-positive or true-negative. A lesion-based analysis of sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) revealed values of 76.6 %, 100 %, 91.4 % and 100 %. A patient-based analysis revealed a sensitivity of 88.1 %. Of 116 patients available for follow-up, 50 received local therapy after ⁶⁸Ga-PSMA-ligand PET/CT. Conclusion ⁶⁸Ga-PSMA-ligand PET/CT can detect recurrent PCa in a high number of patients. In addition, the radiotracer is highly specific for PCa. Tumour detection is positively associated with PSA and ADT. ⁶⁸Ga-PSMA-ligand PET/CT can help delay systemic therapy of PCa.

Purpose Positron emission tomography (PET) with choline tracers has found widespread use for the diagnosis of prostate cancer (PC). However, choline metabolism is not increased in a considerable number of cases, whereas prostate-specific membrane antigen (PSMA) is overexpressed in most PCs. Therefore, a ⁶⁸Ga-labelled PSMA ligand could be superior to choline tracers by obtaining a high contrast. The aim of this study was to compare such a novel tracer with standard choline-based PET/CT. Methods Thirty-seven patients with biochemical relapse of PC [mean prostate-specific antigen (PSA) 11.1 ± 24.1 ng/ml, range 0.01–116] were retrospectively analysed after ¹⁸F-fluoromethylcholine and ⁶⁸Ga-PSMA PET/CT within a time window of 30 days. Radiotracer uptake that was visually considered as PC was semi-quantitatively analysed by measuring the maximum standardized uptake values (SUV_max) of the scans acquired 1 h after injection of ⁶⁸Ga-PSMA complex solution (median 132 MBq, range 59–263 MBq) and ¹⁸F-fluoromethylcholine (median 237 MBq, range 114–374 MBq), respectively. In addition, tumour to background ratios were calculated. Results A total of 78 lesions characteristic for PC were detected in 32 patients using ⁶⁸Ga-PSMA PET/CT and 56 lesions were detected in 26 patients using choline PET/CT. The higher detection rate in ⁶⁸Ga-PSMA PET/CT was statistically significant (p = 0.04). In five patients no lesion was found with both methods. All lesions detected by ¹⁸F-fluoromethylcholine PET/CT were also seen by ⁶⁸Ga-PSMA PET/CT. In ⁶⁸Ga-PSMA PET/CT SUV_max was clearly (>10 %) higher in 62 of 78 lesions (79.1 %) and the tumour to background ratio was clearly (>10 %) higher in 74 of 78 lesions (94.9 %) when compared to ¹⁸F-fluoromethylcholine PET/CT. Conclusion ⁶⁸Ga-PSMA PET/CT can detect lesions characteristic for PC with improved contrast when compared to standard ¹⁸F-fluoromethylcholine PET/CT, especially at low PSA levels.

Purpose The prostate-specific membrane antigen (PSMA) targeted positron-emitting-tomography (PET) tracer ⁶⁸Ga-PSMA-11 shows great promise in the detection of prostate cancer. However, ⁶⁸Ga has several shortcomings as a radiolabel including short half-life and non-ideal energies, and this has motivated consideration of ¹⁸F-labelled analogs. ¹⁸F-PSMA-1007 was selected among several ¹⁸F-PSMA-ligand candidate compounds because it demonstrated high labelling yields, outstanding tumor uptake and fast, non-urinary background clearance. Here, we describe the properties of ¹⁸F-PSMA-1007 in human volunteers and patients. Methods Radiation dosimetry of ¹⁸F-PSMA-1007 was determined in three healthy volunteers who underwent whole-body PET-scans and concomitant blood and urine sampling. Following this, ten patients with high-risk prostate cancer underwent ¹⁸F-PSMA-1007 PET/CT (1 h and 3 h p.i.) and normal organ biodistribution and tumor uptakes were examined. Eight patients underwent prostatectomy with extended pelvic lymphadenectomy. Uptake in intra-prostatic lesions and lymph node metastases were correlated with final histopathology, including PSMA immunostaining. Results With an effective dose of approximately 4.4–5.5 mSv per 200–250 MBq examination, ¹⁸F-PSMA-1007 behaves similar to other PSMA-PET agents as well as to other ¹⁸F-labelled PET-tracers. In comparison to other PSMA-targeting PET-tracers, ¹⁸F-PSMA-1007 has reduced urinary clearance enabling excellent assessment of the prostate. Similar to ¹⁸F-DCFPyL and with slightly slower clearance kinetics than PSMA-11, favorable tumor-to-background ratios are observed 2–3 h after injection. In eight patients, diagnostic findings were successfully validated by histopathology. ¹⁸F-PSMA-1007 PET/CT detected 18 of 19 lymph node metastases in the pelvis, including nodes as small as 1 mm in diameter. Conclusion ¹⁸F-PSMA-1007 performs at least comparably to ⁶⁸Ga-PSMA-11, but its longer half-life combined with its superior energy characteristics and non-urinary excretion overcomes some practical limitations of ⁶⁸Ga-labelled PSMA-targeted tracers.

Prostate-specific membrane antigen (PSMA)–targeted PET imaging recently emerged as a new method for the staging and restaging of prostate cancer. Most published studies investigated the diagnostic potential of ⁶⁸Ga-labeled PSMA agents that are excreted renally. ¹⁸F-PSMA-1007 is a novel PSMA ligand that has excellent preclinical characteristics and that is only minimally excreted by the urinary tract, a potential advantage for pelvic imaging. The aim of this study was to investigate the diagnostic efficacy of ¹⁸F-PSMA-1007 for biochemical recurrence (BCR) after radical prostatectomy. Methods: From 3 academic centers, 251 patients with BCR after radical prostatectomy were evaluated in a retrospective analysis. Patients who had received second-line androgen deprivation therapy (ADT) or chemotherapy were excluded, but prior first-line ADT exposure was allowed. The median prostate-specific antigen (PSA) level was 1.2 ng/mL (range, 0.2–228 ng/mL). All patients underwent PSMA PET/CT at 92 ± 26 min after injection of 301 ± 46 MBq of ¹⁸F-PSMA-1007. The rate of detection of presumed recurrence sites was correlated with the PSA level and original primary Gleason score. A comparison to a subset of patients treated previously with ADT was undertaken. Results: Of the 251 patients, 204 (81.3%) had evidence of recurrence on ¹⁸F-PSMA-1007 PET/CT. The detection rates were 94.0% (79/84), 90.9% (50/55), 74.5% (35/47), and 61.5% (40/65) for PSA levels of greater than or equal to 2, 1 to less than 2, 0.5 to less than 1, and 0.2 to less than 0.5 ng/mL, respectively. ¹⁸F-PSMA-1007 PET/CT revealed local recurrence in 24.7% of patients (n = 62). Lymph node metastases were present in the pelvis in 40.6% of patients (n = 102), in the retroperitoneum in 19.5% of patients (n = 49), and in supradiaphragmatic locations in 12.0% of patients (n = 30). Bone and visceral metastases were detected in 40.2% of patients (n = 101) and in 3.6% of patients (n = 9), respectively. In tumors with higher Gleason scores (≤7 vs. ≥8), detection efficacy trended higher (76.3% vs. 86.7%) but was not statistically significant (P = 0.32). However, detection efficacy was higher in patients who had received ADT (91.7% vs. 78.0%) within 6 mo before imaging (P = 0.0179). Conclusion: ¹⁸F-PSMA-1007 PET/CT offers high detection rates for BCR after radical prostatectomy that are comparable to or better than those published for ⁶⁸Ga-labeled PSMA ligands.