Health Protection Agency to study health effects of MRI scanners
The UK Health Protection Agency has announced its intention to study
the potential harmful effects on patients and medical staff of the high
magnetic fields generated by magnetic resonance imaging machines.
Chairman of the Health Protection Agency, Sir William Stewart
has announced that the Agency’s Board has approved in principle the
need for an epidemiological study of the possible adverse health
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
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 research .
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 Organization. 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 in the UK 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 the well established
scientific technique of 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
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.
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.
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: