The 2003 Nobel Prize in Physiology/Medicine

The 2003 Nobel Prize in Physiology/Medicine goes to Paul C. Lauterbur of the University of Illinois at Urbana-Champaign and
Peter Mansfield of the University of Nottingham for their work in developing magnetic resonance imaging, or MRI.

In the medical world, MRI has become a major imaging technique, but its roots lie in the most basic magnetic physics in the nuclei at the heart of every atom and molecule. Taking advantage of the fact that the body is two-thirds water, MRI obtains images of the hydrogen nuclei in water molecules inside our bodies.

In the early 1970s, while working at the State University of New York at Stony Brook, Lauterbur exploited the magnetic properties of atomic nuclei to yield a two-dimensional image of matter, by introducing gradients in the external magnetic field that surrounds the object to be imaged. Shortly thereafter, Peter Mansfield helped to make MRI a practical imaging procedure, in part by coming up with mathematical methods for processing the radio waves released by hydrogen during the technique.

The origins of MRI go back further, to the late 1930s, when physicist I.I. Rabi of Columbia University demonstrated that one could obtaining abundant information about lithium chloride molecules by manipulating the magnetic "spins" of the molecules' nuclei (Nobel Prize, 1944). Later, physicists E.M. Purcell (Harvard) and Felix Bloch (Stanford) developed nuclear magnetic resonance (NMR) in hydrogen (Nobel Prize, 1952). Two Nobel Prizes in Chemistry (1991 and 2002) have been awarded for achievements in nuclear magnetic resonance.

MRI has been so successful that the original technique has spawned numerous offshoots, such as functional MRI (fMRI), which measures brain activity by detecting oxygen levels in specific brain areas. MRI advances continue at a feverish pace: low-field MRI (Some background articles: Physics Today, Jun 1995, Sep 2001, Jun 92, Oct 2003; Scientific American, May 82, Oct 2001, Jan 83)