Nobel needs better scanning

Technobeat

The electronic monster is the end-product of six decades of research and development. As many as six Nobel Prizes have been awarded for research in MRI and associated fields over the past 50 years.

These prizes have come in the separate disciplines of physics (1952), chemistry (1991, 2002) and medicine (2003). None of the awardees had medical training. The cross-disciplinary nature of MRI work is thus apparent "" but the only medical scientist with claims to pioneering research has been pointedly excluded from the prize.

In 2003, the Nobel Prize for medicine or physiology went to physicist Peter Mansfield of the University of Nottingham and chemist Paul Lauterbur, of the University of Illinois at Urbana-Champaign.

The citation states that Lauterbur "...discovered the possibility to create a two-dimensional picture by introducing gradients in the magnetic field. This made it possible to build up two-dimensional pictures of structures." Mansfield "further developed the utilisation of gradients in the magnetic field. He showed how the signals could be mathematically analysed. Mansfield also showed how extremely fast imaging could be achievable."

By the 1930s, it was known to physicists that atomic nuclei in a magnetic field rotated with frequencies dependent on the strength of the field. In the 1940s, Felix Bloch and Edward Purcell discovered nuclear magnetic resonance (NMR). NMR was later rechristened MRI to avoid the politically-loaded "nuclear".

Bloch-Purcell independently showed that if nuclei were hit with radio waves at specific frequencies, the energy was released back as radio waves of different frequencies as the nuclei reverted to its original energy state over two harmonic time periods. Bloch and Purcell shared the physics Nobel in 1952.

NMR is an analytical tool for chemists. By scanning a molecule with radio waves, the resonances of each atom can be analysed; resonance varies with relative position and type of atoms.

In 1991, Richard Ernst got a chemistry Nobel for contributions to high-resolution imaging. Kurt Wüthrich got the chemistry Nobel in 2002 for developing MRI to determine 3-D structures of biological molecules.

Lauterbur and Mansfield developed the key techniques for scanning a 3-D image in a series of 2-D slices in the 1970s. Different parts of the body contain different amounts of water; by scanning through radio waves, those differences are revealed. Unlike X-rays, MRIs don't use ionised radiations and are considered harmless except for pacemaker-users.

By correlating with organ and tissue structure, a 2-D image is created. Many 2-D "slices" are then reconstructed into a 3-D image. Diseases are diagnosed through physiological changes "" a change of 1 per cent in water content is flagged by an MRI scanner.

For example, a solid cancer tumour has lower water content than healthy tissue making it clearly visible. In sclerosis, the inflamed areas of the brain and spinal cord are visible.

In 1973, Lauterbur had a key insight. He realised that measurements would be more precise if two separate, precisely calibrated, magnetic fields, "gradients" in technical terminology were used. Mansfield did the mathematical work required to analyse spectroscopic signals and turn them into visual images by the echo-planar scanning method (EPS).

The latest award overlooks the contributions of Dr Raymond Damandian. Damnadian's 1971 paper, "Tumor Detection by Magnetic Resonance," detailed the first attempt to use NMR medically.

In 1972, he successfully filed patent for the first MRI scanner, one of 40 patents he holds. Damandian won a patent infringement lawsuit award for $ 110 million in 1992 against General Electric.

His original work had several flaws and modern MRI design is very different from Damandian's 1972 concept. But it was by critiquing the Damandian experiments in 1973 that Lauterbur developed his gradient method. Damandian has vented his disappointment in full-page ads in The Washington Post.

The ads included cut-out protest forms, which can be mailed to the Nobel Committee. While the Nobels often cause controversy in the dog-eat-dog world of research, this is the first time such open dissent has been witnessed.