Like every other chemist using magnetic fields and radio waves to identify molecules in the early 1970s, Paul Lauterbur was frustrated that his data were often ruined by seemingly meaningless signals.
But unlike the others, Lauterbur had a flash of insight and realized that these signals were not useless noise, but whisperings that revealed the precise location of the atoms in a test tube–and for that, the University of Illinois professor was awarded the 2003 Nobel Prize in medicine on Monday.
That brainstorm helped bring the world magnetic resonance imaging, a technique that enables doctors to peer inside the human body as never before to see disorders and disease processes.
Lauterbur, 74, shares the $1.3 million prize with Briton Sir Peter Mansfield, 69. They worked independently, but together are credited for MRI, considered a milestone in medicine that has revolutionized diagnoses, treatment and research.
MRI uses powerful magnetic fields and radio signals to stimulate hydrogen atoms in the body to reveal their positions, thereby providing detailed images of internal structures.
Lauterbur said his wife, Joan Dawson, who answered the telephone at 3:30 a.m., awakened him at home in Champaign-Urbana.
“I was still sound asleep, and she poked me and said `Stockholm is calling,’ which of course to scientists is shorthand for this kind of thing,” Lauterbur said. “I woke up reasonably quickly.”
Surprised despite rumors
Despite having been mentioned as a Nobel Prize candidate in the past, Lauterbur said, he was still surprised. “One never knows if and when it might happen because the Swedish Academy has knowledge of a lot of work that has been influential and helpful in science.”
MRI has become the most effective method of imaging the brain, spinal cord, muscles, joints and heart, without the need for X-rays or surgery.
Lauterbur invented the concept in the early 1970s and produced his first MRI image of a patient in 1980. Within five years, MRI became the hottest new diagnostic tool in medicine and spread rapidly to medical centers across the world. An estimated 60 million MRI tests are now performed annually, and the number continues to grow.
Lauterbur has undergone MRI himself, and the results were negative. “It’s difficult to go on for so many years without having people wonder about certain things in your body that doctors would like to know about,” he said.
2nd Nobel in a week
The Nobel Prize in medicine came less than a week after John Maxwell Coetzee, a University of Chicago professor and South African-born novelist, won the Nobel in literature. The last scientist in Illinois to win the prize in medicine was the U. of C.’s Charles Huggins in 1966, although numerous prizes in medicine have been awarded to scientists who have been affiliated with Illinois medical centers.
The Nobel committee, which called MRI “a medical breakthrough,” cited Lauterbur for discovering the concept and promoting the development of magnetic nuclear imaging, and Mansfield for innovative techniques that made the process widely available.
“The first MRI image I saw as an intern in 1981 made my jaw drop,” said Dr. David Levin, professor of radiology and co-director of the University of Chicago’s Brain Research Imaging Center. “It was absolutely phenomenal. Twenty years later, we’re looking at things that would have been absolutely science fiction in 1980.”
Associate followed Lauterbur
Levin worked in Lauterbur’s laboratory at the State University of New York in Stony Brook in 1983 as a graduate student and continues to collaborate with Lauterbur. Lauterbur joined the U. of I. in 1985 and is now director of its Biomedical Magnetic Resonance Laboratory.
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“I’m just so happy for him,” Levin said. “It’s been obvious to those of us in the field that he should have gotten the Nobel Prize a long time ago.
“He wasn’t just the inventor of the modern method of imaging, but he also contributed many other things. He foresaw all the major developments in the field.”
Lauterbur was a chemist at Stony Brook in the early 1970s when he had a sudden insight into MRI. He was using a common chemistry technique called nuclear magnetic resonance to analyze test-tube samples of chemicals.
A test tube is put into a small but strong magnet to cause the atoms to emit tiny radio signals that would reveal the composition of a chemical. But there was a major problem: The magnetic field on one side of the test tube was always slightly different than the field on the other side, blurring the radio signals and trashing the results of the analysis.
Lauterbur, like other chemists, tried and failed to get rid of the bedeviling radio-signal variations. Pausing in his futile efforts, Lauterbur thought about what the mixed-up radio signals might be telling him.
He suddenly realized that these radio signal variations were providing imaging information about the location of atoms in the test tube, Levin said. Lauterbur realized that the variations were showing the locations of different densities of atoms in the mixture, which allowed him to infer the structure of the sample.
“It was a eureka moment,” Levin said. “He suddenly realized that what everyone else had been sweeping under the rug and trying to get rid of for 25 years actually had useful information in it, and it could be used to create an image.”
Today’s MRI machines use powerful magnets, some big enough to enclose the entire body, to align the nuclei of hydrogen atoms in the same direction. Patients are then exposed to small radio signals, which impart a slight amount of energy to the nuclei, kicking their alignment in the opposite direction.
Nuclei emit energy
When the outside radio signal is turned off, the nuclei drop back to their original alignment inside the magnetic field, emitting energy in the form of tiny radio signals as they do so.
The radio signals emitted by the nuclei vary slightly depending on where they are in the body and whether their neighboring atoms are in hard or soft tissue or liquid. Lauterbur then discovered that by gradually changing the strength of the surrounding magnetic field, the nuclei emitting radio signals could be placed in precise locations.
“He discovered how to take the radio signals that were simultaneously coming from the entire patient and then unscramble them so that he could figure out which part of that jumble of signals came from which part of the body,” Levin said.
After being toasted at a reception in Levis Faculty Center in Urbana on Monday, Lauterbur, who continues to do research on problems in chemistry, was met there by students from a 4 p.m. chemistry class he was late for. The students, who had been waiting in their regular classroom, decided to walk to the center to corner Lauterbur.
“The meeting came to you,” one young female student said.
Lauterbur chuckled: “You know you’ve had a big day when the department head is serving as your chauffeur and the chancellor is showing you around.
“You know the world is turned upside down.”
With that, Lauterbur turned to what was really on his mind–experiments that the students could conduct to determine what the chemistry might have been on the Earth that gave birth to early life forms.