Today’s magnetic resonance imaging, or MRI, machines create body scan images almost instantly and can be used to diagnose disorders such as multiple sclerosis and cancer or injuries such as strained or torn muscles. The technology certainly has come a long way from the first MRI machine, which took almost 5 hours to produce one grainy image.

Raymond Damadian (1936–), then a physician at the State University of New York Downstate Medical Center, began experimenting with nuclear magnetic resonance in the 1960s. He proposed the first magnetic resonance scanner, which could presumably use magnetic waves to produce images of the body based on the radio frequencies emitted by atomic nuclei in the body. Experimenting on rats, Damadian had discovered dramatic differences in the signals emitted by cancerous as opposed to healthy human tissue, leading him to suspect that this could help diagnose disease.

The first MRI performed on a human, in 1977, provided a grainy (by today’s standards, at least) image of the heart, lungs, and chest wall, and the patient suffered no side effects. Since then, countless advances have been made to render MRIs faster, less claustrophobic, and more able to show minute details and chemical compositions of human tissue. The first commercial version was unveiled 3 years later. Recent developments include the FONAR 360, a full-size room with two magnetic poles projecting from the ceiling and the floor, and Stand-Up MRI, the only machine that allows patients to be scanned while standing.

Most MRI machines are about 7 feet by 7 feet by 10 feet, although models are becoming smaller, lighter, and less uncomfortable for the patient. They consist of a giant magnet with a horizontal tube (called the bore) running through the center. Patients lie on their backs and are slid into the bore so that they are in the center of the magnetic field. Alternating magnetic fields are then sent out to explore the body, building a two-dimensional or three-dimensional map of its structures and tissues by computer processing of changes in the fields caused by the shifting responses of the body’s atoms.

ADDITIONAL FACTS

  1. Damadian named his first MRI prototype Indomitable, in reference to the obstacles and skepticism he’d had to overcome. It is now on display at the Smithsonian Institution.
  2. Metal objects such as paper clips, pens, and keys can become dangerous projectiles when an MRI magnet is turned on, and they are strictly forbidden in hospital scanning rooms.
  3. Patients with implantable pacemakers, steel aneurysm clips in the brain, or certain dental or orthopedic implants may not be able to undergo MRIs because the magnet may cause the objects to shift out of place or malfunction.