MODEL RELEASED. MRI scan. Lying on his back, a man enters the extra-wide chamber of an MRI (Magnetic Resonance Imaging) scanner designed for the obese or claustrophobic. A nurse stands beside him, holding his arm. MRI scanners can produce images of a slice" through the human body in any direction. Unlike X-rays, they produce no harmful radiation, depending instead on tiny radio signals produced when the body's hydrogen atoms are made to fall out of magnetic alignment. The technique is particularly good for studying soft tissues like the brain, spinal cord and blood vessels. In normal MRI scanners, the patient must lie very still in a narrow cylinder for about 30 minutes."