A doctor can diagnose some disorders of the bladder and urethra by looking through a flexible viewing tube (cystoscope, a type of endoscope). A cystoscope, which has a diameter about the size of a pencil, may be between 1 and 5 feet (30 to 150 centimeters) in length, but only 6 to 12 inches (about 15 to 30 centimeters) of the scope are inserted into the urethra and bladder. Most cystoscopes contain a light source and a small camera, which allows the doctor to view the inside of the bladder and urethra. Many cystoscopes also contain tools that allow the doctor to obtain a sample (biopsy) of the bladder lining. Cystoscopy can be done while a person is awake and causes only minor discomfort. The doctor usually inserts an anesthetic gel into the urethra before the procedure. Possible complications include minor bleeding and infection.