Cystoscopy is the examination of the urethra and bladder cavity using long thin viewing tube inserted up the urethra. Diagnostic uses of cystoscopy include inspection of the bladder cavity for stones, tumors, and sites of bleeding and infection, as well as the obtaining of urine samples from each kidney. In addition, by means of injected dye, X-rays can be taken to investigate the site of any obstruction to the flow of urine. Local anesthesia is used for the procedure.