Medical specialty dealing with the urinary system and male reproductive organs. It traces its origin to medieval lithologists, itinerant healers who specialized in surgical removal of bladder stones. The Spanish surgeon Francisco Díaz wrote the first treatises on urinary-tract disease (1588) and is regarded as the founder of modern urology. Most modern urological procedures originated in the 19th century. Today, urologists use bladder catheters (see catheterization), the cystoscope (to view the inside of the bladder), and various diagnostic imaging techniques; treat prostatic disorders; perform vasectomies; and may surgically remove stones in the urinary tract and cancers of the kidneys, bladder, and testicles. Urology deals mostly with male patients; the urinary tract in females may be treated by gynecologists (see obstetrics and gynecology)