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Home News centre National Press Releases 2008 Press Releases ›  Health Protection Agency to study the health effects of Magnetic Resonance Imaging

Health Protection Agency to study the health effects of Magnetic Resonance Imaging

21 May 2008

The Chairman of the Health Protection Agency, Sir William Stewart today announced that the Agency’s Board had approved in principle the need for an epidemiological study of possible adverse health effects from high static field Magnetic Resonance Imaging (MRI) machines.

Sir William said: “MRI scanning has some undoubted benefits in medicine, especially as an aid to accurate clinical diagnosis. However we need to bear in mind that the magnetic fields produced by the machines are quite substantial and that these fields are increasing in order to achieve improved clarity of image. The exposures to patients and medical staff from the magnetic fields can be high and there is a shortage of information on possible adverse long term health effects. The Agency’s Board therefore considers more research is needed in this area.”

The announcement follows a report to the Board from the Agency’s independent Advisory Group on Non-ionising Radiation (AGNIR) which made a number of recommendations on new areas for research1.  This followed a thorough examination of the sources of MRI exposure and the scientific evidence for biological effects and health effects. In particular the Chairman of AGNIR, Professor Anthony Swerdlow, said “There is a pressing need for a well-conducted study of mortality and cancer incidence in workers with high occupational exposures to static magnetic fields, particularly those associated with medical MRI scanners.”

The Board also noted that the view that there is a need for more epidemiological research on people exposed to MRI is shared by the World Health Organization2. The WHO points out that an international collaborative study may be the most effective way forward, because it would ensure there are sufficient numbers of exposed cases in the study to draw accurate conclusions. The Agency will now examine the feasibility of such a study with specialists here and abroad, with the aim of launching such a study as soon as possible.

The Agency will be setting up a Working Group under the Chairmanship of Board member Professor Andrew Hall. The Group will undertake a detailed review in order to advise the HPA Board on future research on possible long-term health consequences in people exposed to the static magnetic fields associated with Magnetic Resonance Imaging.  Emphasis will be placed on identifying appropriate study groups and their exposures, the diseases of potential concern and the feasibility of future epidemiological investigations.  The Group will report to the HPA Board within one year of commencement of the scoping study.

Magnetic Resonance Imaging (MRI) was first developed 30 years ago as an aid to medical diagnosis. It is based on a well established scientific technique, nuclear magnetic resonance, which uses the interaction of magnetic fields with the spin of the nuclei of atoms to provide detailed information on the constituents of chemicals and biological materials. MRI can provide excellent, detailed images of the body’s soft tissue and is an alternative to using x-ray techniques such as computed tomography (CT). MRI does not use ionising radiation and this can be a distinct advantage for examinations of children or for abdominal examinations where radiation doses can be high. However, MRI requires large magnetic fields for successful scanning and hence the need for a study of people who work in the fields. People are exposed to high magnetic fields in industry and elsewhere, but MRI produces the highest magnetic fields in use today, and hence the need for a study of people who regularly work with the machines.

Press Enquires;  Contact the Chilton press office. Tel +44 (0) 1235- 822744/ 822745/822876, Email:

Notes to Editors

  1. Health Protection Agency (2008). Static Magnetic Fields. Report of the independent Advisory Group on Non-ionising Radiation. Documents of the Health Protection Agency. RCE – 6. May 2008. ISBN: 978-0-85951-616-7. Available to download from the HPA website: Printed copy £32.00 + 10% postage and packing, available from CRCE Information Office. Telephone 01235 822742/822603 or email
  2. World Health Organization (2006). Environmental Health Criteria 232. Static Fields. Geneva. ISBN 92 4 157232 9; ISSN 0250-863X
  3. The independent Advisory Group on Non-ionising Radiation (AGNIR) reports to the Board of the HPA. Its terms of reference are “to review work on the biological effects of non-ionising radiation relevant to human health and to advise on research priorities”.
  4. AGNIR is chaired by Professor Anthony Swerdlow, The Institute of Cancer Research, University of London. A full list of members of the Group can be found in the report published today (see link above).
  5. AGNIR has previously issued reports concerned with the health effects of extremely low frequency (ELF) electromagnetic fields and radiofrequency fields. These have included advice on the possible health effects from exposures to the fields produced by electricity power lines, visual display units and mobile phone technology.  A full list of publications is contained in the report published today (see link above).
  6. Large static magnetic fields produce forces in cells and tissues in the body and electric currents can be induced by movement in the field. Some people experience sensations at 2T, such as a strange taste in the mouth and vertigo.  At high fields, electric currents could interfere with cardiovascular functioning and at fields up to 8T some measurable cardiovascular effects have been observed in people. There is no evidence of any long term effects in people, but there are few data about this, and there have been no long terms studies of mortality or cancer occurrence in people who work with magnetic resonance facilities.

Last reviewed: 24 December 2008