It was proved that mean prostate maximum standardized uptake value (SUVmax) was significantly higher in prostate cancer than in benign lesions (19.56 ± 18.11 vs. 4.21 ± 1.5, p = 0.00001), in patients with PSA > 20 ng/mL versus PSA < 20 ng/mL (19.1 ± 20.6 vs. 6.01 ± 5.4, p—0.0052) and in patients with Gleason’s score (GS) score > 7 vs. GS ≤ 7 (28.1 ± 20.3 vs. 10.2 ± 8.9, p—0.010). The gene discussed is KLK3; the disease is prostate cancer.