Sir Peter Mansfield
Nobel prize-winning physicist who developed MRI scanning and tested the technology on himself
SIR PETER MANSFIELD, the physicist, who has died aged 83, won, with Paul Lauterbur, the 2003 Nobel prize for Physiology or Medicine for developing magnetic resonance imaging (MRI); his achievement was all the more remarkable in that he had started his working life as an apprentice printer after leaving school aged 15, having been advised by a careers teacher that he was not bright enough to be a scientist.
The technique of MRI has changed the face of modern medicine by enabling doctors to see extraordinarily detailed images of the internal workings of the body without the use of potentially harmful ionising radiation and without invasive surgery. MRI can reveal, for example, whether lower-back pain stems from pressure on a nerve or the spinal cord; it can show how the heart operates and lay out “road maps” for surgeons before they operate for cancer or other diseases.
It is also unique in its ability to unpick the quirks of human thought; doctors have been able to identify the portion of the brain that may cause stuttering and the portion that guides decision making. Car manufacturers have discovered, using MRI, that when we look at a sports car with its eye-like headlights, the portion of the brain that responds to faces is activated.
The technique works by exploiting the fact that the nuclei of atoms have a spin that can be controlled by a powerful magnetic field. The spinning nuclei orientate themselves in the magnetic field and can absorb radio energy. When they return to their original state, they emit radio waves at characteristic frequencies that convey information about the chemical structure they find themselves in.
In effect, the nuclei of atoms act as tiny radio transmitters to broadcast information about themselves. MRI is particularly effective in medical imaging because the body is largely composed of water, and hydrogen atoms – two to every molecule of water – are the best resonators of all. Different types of tissues within organs – including cancer cells – have different water content, which shows up as different colours on an MRI scan.
MRI became available to doctors in the 1980s, though its origins go back to the late 1930s when the American physicist I I Rabi suggested that information about the nuclear cores of atoms could be obtained by studying the magnetism of protons, and in the 1940s when the physicists EM Purcell and Felix Bloch discovered what they termed nuclear magnetic resonance (NMR), the phenomenon that makes MRI possible.
In the early 1970s Paul Lauterbur showed how to make two-dimensional images of the body with magnetic resonance, by introducing gradations or gradients in the external magnetic field, though the images were fuzzy and the technique was slow. It was Mansfield who turned Lauterbur’s discovery into a useful diagnostic tool.
Working at the University of Nottingham, Mansfield developed Lauterbur’s magnetic gradient technique further and created a mathematical method of swiftly deciphering the radio signals and turning them into three-dimensional images of the internal structures of the body. This allowed extremely fast imaging to take place.
Mansfield and his team began testing the new technique on plants and bits of animal tissue. When the time came to test their technology on a live subject, none of them were biologists and they had no experience with laboratory animals, so Mansfield decided to volunteer himself.
Though he later admitted to some misgivings about the possible effects on his health, the technique has turned out to be not only highly effective but also safer than any other method of internal imaging. Mansfield went on to make further improvements in the technique, including increasing its speed enormously so that changes in organs such as the brain could be followed as they occurred.
The Nobel committee’s decision to recognise Mansfield’s achievement, 30 years after he had carried out his research and long after MRI had become an established diagnostic tool in hospitals, was generally regarded as long overdue. There are now more than 36,000 MRI scanners at work all over the world, carrying out some 80 million scans a year.
One of nine children of a gas-fitter, Peter Mansfield was born in Lambeth on October 9 1933. Although his education at a central school in Peckham (now William Penn School) left him with no qualifications, his scientific curiosity had been kindled by the V1 flying bombs and the V2 rockets that fell on London in 1944, when he was 11. He collected fragments and taught himself about weapons and explosives.
On leaving school he became an apprentice compositor at a printing works in the City of London, but soon got bored and, aged 19, got a job as a scientific assistant at the Rocket Propulsion Department, part of the Ministry of Supply, near Aylesbury.
After an unrewarding period of National Service in the stores of the Royal Army Service Corps, he studied for A-levels at night school then won a place at Queen Mary College, east London, where he took a degree in Physics and went on to do a doctorate in nuclear magnetic resonance, a technique which was then only used for the study of chemical structure.
From 1962 he worked as a research associate at the University of Illinois until 1964, when he was appointed a lecturer in Physics at Nottingham University. He remained at Nottingham for the rest of his scientific career, becoming Professor of Physics in 1979.
The Medical Research Council’s decision to fund Mansfield’s research into MRI was brave, as it seemed doubtful whether it would bear fruit. Yet the celebrations of his success were overshadowed by the bitterness he felt over Britain’s failure to exploit his invention commercially.
The lack of will from Government or industry to create an MRI industry in Britain, and the initial lack of orders from the National Health Service (many of the machines in Britain’s hospitals have been bought with private money), meant that the lion’s share of the market in MRI scanners, worth some £600 million a year by 1988, went to American and Japanese manufacturers.
MRI has been so successful that the original technique has spawned numerous offshoots. Low-field MRI offers the prospect of cheaper and more portable equipment; susceptibility weighted imaging (SWI) offers images of small haemorrhages in minute detail. MRI is even being tested as a tool for detecting viruses.
Mansfield was a soft-spoken man, and his interests included learning foreign languages and flying – he held a pilot’s licence for both aeroplanes and helicopters.
His achievements were recognised in numerous honours and awards, including the Gold Medal of the Society of Magnetic Resonance in Medicine (1983); the Royal Society’s Wellcome Medal (1984), the European Magnetic Resonance Award (1988) and the Royal Society’s Mullard Medal (1993). He was elected a Fellow of the Royal Society in 1987, made an honorary Member of the British Institute of Radiology in 1993 and knighted in 1995.
Peter Mansfield married, in 1962, Jean Kibble, who survives him with their two daughters.
Professor Sir Peter Mansfield, born October 9 1933, died February 8 2017
Mansfield in his lab at Nottingham: he left school without any qualifications, but his interest in science had been kindled by the V1 flying bombs and V2 rockets that fell on London when he was 11