Several studies have already suggested that Ki-67 is a useful marker by significantly correlating with biologic aggressiveness and prognosis in prostate cancer.15,38–40 Our results, in agreement with the study by Piert et al.,35 demonstrate that 11C-Choline uptake measured by PET/CT could reflect proliferative activity of prostate cancer. Here, MKI67 is linked to prostate carcinoma.