Urinary reflux. Coloured Gamma Camera Scan (scintigram) of the human abdomen, showing urinary reflux from the bladder to the kidneys. The partly emptied bladder is red; kidneys are at upper frame (faint white outlines). Urine is coloured white & has flowed back (refluxed) up to the kidneys. This is due to a failure of the valves at the lower end of the ureters to keep urine in the bladder. It may lead to kidney damage (nephropathy). Gamma scanning uses a radioactive tracer (Technetium- 99m) injected here into the urine, and detected as flashes of light by a gamma camera. See photo: M195/045 for an earlier stage of urinary reflux.