9 October 2003—An American and a Briton have been awarded this year's Nobel Prize in Physiology or Medicine for their pioneering work in the development of magnetic resonance imaging (MRI), a widely used technique that produces high-resolution images of internal organs within the human body. Paul C. Lauterbur of the University of Illinois at Urbana-Champaign and Sir Peter Mansfield of the University of Nottingham in England will share the US $1.3 million prize, which is awarded annually by the Nobel Assembly of the Karolinska Institute in Stockholm.
MRI equipment generates a magnetic field that forces the nuclei of hydrogen atoms in the body's water molecules to align in an orderly fashion. These nuclei are then exposed to pulsing radio waves, which make then vibrate, or resonate. As the nuclei vibrate, they emit radio signals of a precise frequency that can be analyzed by a computer to compose an image. A series of two-dimensional images can then be stacked to produce stunning 3-D views of inside parts of the body.
Lauterbur made a key discovery in the early 1970s when he began to employ a graded magnetic field to successfully produce the first images with the new technique. Mansfield advanced the magnetic gradient technique and created mathematical tools for processing the signals released by the hydrogen nuclei.
Their work transformed an initially cumbersome method into a practical, widely deployed medical imaging procedure. The painless diagnostic instrument used for MRI testing has helped doctors detect diseases in its earliest stages without subjecting patients to invasive surgery or potentially harmful X-rays. In 2002, about 22 000 MRI scanners were in use worldwide, and more than 60 million MRI exams were performed.
Lauterbur was until recently a Senior Member of the IEEE and won the 1987 IEEE Medal of Honor. He was coauthor of a book on MRI techniques, which was published by IEEE Press and John Wiley & Sons in October 1999: Principles of Magnetic Resonance Imaging: A Signal Processing Perspective by Zhi-Pei Ling and Paul C. Lauterbur [ http://www.wiley.com/WileyCDA/WileyTitle/productCd-0780347234,descCd- tableOfContents.html].