Don't spoil this success story

EU moves to limit the use of MRI are misplaced and will impede future research, says Peter Mansfield

The development of magnetic resonance imaging (MRI) has been one of the great success stories of research and development in medical science of recent decades. During my lifetime, I have been privileged to contribute to that development and to watch it grow from an idea in my physics notebook, to a technique that has contributed to the safe diagnosis of more than 100 million patients.

Therefore, the introduction of a European directive that will severely limit the use of MRI, and which takes no account of the experience of those 100 million patients, is profoundly disturbing. The European Union Physical Agents Directive 2004, which must become part of UK law by 2008, seeks to limit occupational exposure to certain electromagnetic frequencies, not because there is any evidence of harm but because, hypothetically, there could be a risk.

Being concerned narrowly with occupational health, the directive has been drawn up without reference to the broader context of applications in the medical sphere or the likely impact of limits on research. The hypothetical risks it seeks to guard against are not balanced against the real benefits.

For example, when used for both diagnosis and treatment, MRI often replaces X-ray techniques, reducing the inevitable risk to patients, and indeed to staff, that results from radiation exposure. Furthermore, it is also clear that MRI can reduce the risks associated with major invasive procedures such as brain surgery, if these are performed in a magmetic resonance scanner. There is no known risk to health associated with MRI.

Research is also finding new applications. At Nottingham Univesity, we have long held the view that MRI has a potential role not only in diagnosis of disease but also in its treatment, because it enables the doctor to look inside a patient while treating them with drugs, surgery or by other means.

We are just witnessing the birth of this field of interventional MRI.

Similarly the technology has developed sufficiently to allow ultra-high field MRI to take off, which will allow us to look inside the body with a detail previously possible only by performing operations.

I have been distressed to find that the future development of MRI is being stifled by recent moves to regulate exposure to the electromagnetic fields associated with the technique, using absolute exposure limits that are based on very uncertain science. I have always considered it necessary to behave prudently when working with physical forces of which we have limited knowledge. However, it is necessary to balance possible small chances of an unknown and hitherto unobservable risk against the real benefits to human health that will accrue from the future exploitation of MRI.

The burden of proof in such circumstances should rest with the national health and safety agencies, in the UK and in Europe. A promising area of research with such a strong track record for delivering applications that improve people's lives should not be shut down on the basis of unsubstantiated concerns.

Sir Peter Mansfield FRS, joint winner of the Nobel prize for medicine October 2003, is emeritus professor of physics at the Magnetic Resonance Centre, Nottingham University.