Figure 1From: Randomized phase II trial of urethral sparing intensity modulated radiation therapy in low-risk prostate cancer: implications for focal therapyProstatic Sub-structure Anatomy. Mid-sagittal view of the prostatic anatomy. Proximal urethra is defined from the bladder to the inferior-most aspect of the transitional zone/central zone (TZ/CZ) and peripheral zone (PZ) border. Distal urethra is defined from the TZ/CZ – PZ border to the prostate/pelvic floor border.Back to article page