During Whole Gland HIFU, the entire prostate is ablated, including the prostatic urethra. However, the urethra is derived from a different type of tissue (bladder squamous-type epithelium) rather than prostatic tissue (glandular, fibrotic and muscular). While the urethra is an important anatomical structure, the sphincter and bladder neck are more important to maintaining the urinary function. However, during Focal HIFU, the urethra is usually spared (not ablated).