Is Computed Tomography Safe?

Ms. C., a 59-year-old schoolteacher, awoke on September 8, 2009, with facial paralysis. In a local emergency room, she underwent computed tomographic (CT) and magnetic resonance imaging (MRI) brain scanning. The scans were normal, Bell's palsy was diagnosed, and the symptoms resolved over the next few weeks. Two weeks later, Ms. C. began losing her hair in a band-like distribution, and the following week she awoke with vertigo and confusion and returned to the emergency room, where repeat CT and MRI scans were normal. Fatigue, malaise, memory loss, and confusion began soon thereafter and have continued, making it difficult for . . .