In the er dueto sharp pain my kidney area. doc recommended ct scan since the xray and ultra sound did not show. what are the risk of 1 time ct scan?

1 in 2000 : Estimated risk of cancer from a CT scan is 1 in 2000. This means is that if 2000 people get a CT, one may eventually get a cancer related to the exposure. CT is fastest & most accurate way to see and measure stone. Ultrasound sees if kidneys are blocked, but often can't find the stone. X-ray will only see large stones (most stones are small). You can ask for a limited CT, from kidney to bladder.