A CT scan can usually diagnose life-threatening conditions such as bleeding, blood clots, or cancer. Early diagnosis of these conditions can be potentially life-saving. Whereas, CT scans use X-rays, and all X-rays produce ionizing radiation. Ionizing radiation has the potential to cause biological effects in living tissues. It is a risk that increases with the number of risks added to a person's life. However, the risk of developing cancer from X-ray radiation exposure is generally small.