Consultation on the protection of patients and volunteers undergoing MRI examinations

The Health Protection Agency has published a consultation document on its website about the protection of patients and volunteers undergoing magnetic resonance imaging (MRI) examinations.

The document will form the basis for the Agency's advice to the Department of Health, scheduled for completion in March 2008. The new advice will replace that provided in 1991 by the National Radiological Protection Board (NRPB).

MRI is a non-invasive technique which has gained widespread use in medicine and research to provide internal images of the body. The technique is also being used in operations to guide, monitor and control interventional procedures. At the end of 2006 it has been estimated that there were approximately 500 fixed magnetic resonance scanners involved in human imaging, installed at 360 sites across the UK . Unlike computerised tomography (CT) x-ray scans, MRI does not involve the use of ionising radiation. However MRI equipment does produce large static magnetic fields, low frequency (switched gradient) magnetic fields, radio frequency fields and acoustic noise, all of which have the potential to cause harm if not controlled.

The new advice is being developed by a group comprising scientific staff from the Agency's Radiation Protection Division and external experts in the field of MRI and its applications. The group has reviewed published scientific data in the life and physical sciences about the possible adverse effects on people of exposure to MRI. The reviewers took into account the clear benefits to individual patients undergoing MRI examinations and the potential benefits from research involving volunteer exposures which can increase medical knowledge.

The Agency has already completed an expert consultation exercise. The comments and suggestions received were generally very positive and helpful in further developing the advice. We are now seeking to engage other interested parties in open consultation by inviting comments and suggestions on the document published on the website, which will be available for a period of three months, ending 31 January 2008. The feedback will be used to assist the Agency to develop the formal advice to Government.