This investigation compares how effectively 68Ga-PSMA and 68Ga-DOTA-RM2 PET/MRI identify prostate cancer (PCa) recurrence following initial therapy and examines how the results of these two tracers relate to clinical and pathological variables. Thirty-five men experiencing biochemical relapse (BCR) underwent restaging with 68Ga-PSMA PET/MRI, and 31 of them also completed a 68Ga-DOTA-RM2 PET/MRI examination within a period of up to 16 days (mean interval: 3 days; range: 2–16 days). Imaging obtained from both modalities was assessed qualitatively and quantitatively at the patient and lesion levels, and findings were verified through clinical evaluation and subsequent diagnostic follow-up. Statistical analyses were performed using Fisher’s exact test and the Mann-Whitney U test, adopting a p-value threshold of <0.05. The study population had an average age of 70 years (49–84) and a mean PSA concentration of 1.88 ng/mL at the time of imaging (0.21–14.4). Compared with 68Ga-DOTA-RM2 PET/MRI, the 68Ga-PSMA scan detected disease more frequently, revealing 95 lesions in 26 of 35 patients, while the RM2 tracer identified 41 lesions in 15 of 31 patients (p = 0.016 and 0.002). Among the 31 men who underwent both scans, 11 showed inconsistent results; 10 were positive only on 68Ga-PSMA, and follow-up confirmed 9 of these as genuine recurrences, with 1 determined to be a false-positive finding. Higher PSA values and shorter PSA doubling time (DT) were associated with a greater number of 68Ga-PSMA–avid lesions (p = 0.006 and 0.044), while no link emerged between imaging results and Gleason score. Overall, 68Ga-PSMA PET/MRI demonstrated superior ability to identify recurrent PCa compared with 68Ga-DOTA-RM2, and the burden of PSMA-positive lesions correlated with PSA metrics, suggesting a potential prognostic role.
