18F-rhPSMA-7 positron emission tomography for the detection of biochemical recurrence of prostate cancer following radical prostatectomy

(18)F-labelled prostate-specific membrane antigen (PSMA) positron emission tomography (PET) tracers are increasingly used in preference to (68)Ga-PSMA-11 for restaging biochemical recurrence (BCR) of prostate cancer. They are associated with longer half-lives, larger scale production and lower positron range compared with their (68)Ga-labelled counterparts. Here we describe the efficacy of (18)F-labelled radiohybrid PSMA, rhPSMA-7, a novel theranostic PSMA-targeting agent for imaging BCR of prostate cancer. Methods: Datasets from 261 consecutive patients with non-castrate BCR after radical prostatectomy who underwent (18)F-rhPSMA-7 PET/CT at our institution between June 2017 and March 2018 were reviewed retrospectively. All lesions suspicious for recurrent prostate cancer were recorded. The detection rate of presumed recurrence sites was correlated with patients' PSA level, primary Gleason score, and prior therapy (androgen deprivation therapy [ADT)] and external beam radiation therapy [EBRT]). Results: The 261 patients had a median PSA level of 0.96 (range, 0.01-400) ng/mL. The median injected activity of (18)F-rhPSMA-7 was 336 MBq, with a median uptake time of 76 min. In total, 211 patients (81%) patients showed pathological findings on (18)F-rhPSMA-7 PET/CT. The detection rates were 71% (42/59), 86% (44/51), 86% (42/49) and 95% (76/80) at PSA levels of 0.2 to /=2 ng/mL, respectively. In 32% (7/22) patients with a PSA /= 8, P = 0.38). Conclusion: (18)F-rhPSMA-7 PET/CT offers superb detection rates in early BCR after radical prostatectomy, especially among patients with low PSA values.