According to the Food and Drug Administration, the increased risk of any one individual having a deadly cancer as a result of a standard CT scan is roughly one in 2,000. Because MRIs do not employ ionizing radiation, there is no chance of cancer being increased. However, they take substantially longer to complete than CT scans. So if you have multiple images taken over time, then you are absorbing more radiation over time. The most effective way to minimize your exposure to radiation is through careful choice of imaging tests. For example, instead of using CT for full body scans, clinicians may choose to use magnetic resonance imaging (MRI) because it is more sensitive to soft tissue abnormalities. Also, patients who are considered at high risk for developing cancer can have periodic scans with radiopharmaceuticals that are administered into certain tissues or organs. These scans are called positron emission tomography (PET) scans. An average chest x-ray has a dose level of about 0.5 mSv. An average mammogram has a dose level of about 10 mSv. An average head CT scan has a dose level of about 5 mSv. An average abdominal CT scan has a dose level of about 15 mSv. An average pelvic CT scan has a dose level of about 20 mSv. An average MRI has a dose level of about 1 mSv. A PET scan has a dose level of about 5 mSv.