MKI67 and neoplasm: According to a more recent study by Piert et al. 35, in which the radioactivity concentrations of the tumour (T) and benign prostate background (B) were measured and their ratios (T/B) were calculated, high Gleason score (≥4+3) and Ki-67 index (≥5%) were significantly associated with an increased SUV T/B ratio in 11C-Choline PET/CT imaging.