Severe headaches are a misery, whether they cause a dull ache or a steady, stabbing, or blinding pain. Such pain rarely comes from something catastrophic, like a tumor or a bleeding in the brain. Yet an estimated 12% of people with headaches get brain scans. A new study shows that these unnecessary scans add several billion dollars a year to health care costs for very little benefit. Excessive brain scanning costs more than just dollars. Repeated CT scans deliver enough radiation to increase the odds of developing cancer. Scans also tend to lead to more scanning if the test turns up something strange. Many people who see a doctor because of severe and recurrent migraine headaches don’t need brain scans. They need the right therapy to stop their pain.