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Exposures, limits, safe systems of work. This section explores safety issues in magnetic resonance imaging.

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MRI Safety Guidelines

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What current MRI safety guidelines are available? (UK relevant)

The following documents may be freely downloaded unless specified otherwise:

• HPA-RPD (was NRPB) guidelines:
  • Advice on Limiting Exposure to Electromagnetic Fields (0-300 GHz) (2004)
  • Principles for the Protection of Patients and Volunteers During Clinical Magnetic Resonance Diagnostic Procedures (may be ordered online) (1991)
• MHRA (was MDA) guidelines:
  • Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use (2007).
• IPEM policy statement:
  • Scientific Safety Advice to MRI Units that undertake Human Imaging [PDF] (2013).
• British Standard 60601-2-33 (same as IEC 60601-2-33)
  • Go to BSi and type 60601-2-33 into the search box. You may download a copy if you have an Athens password.
• ICNIRP
  • Statement on Medical Magnetic Resonance (MR) Procedures: Protection Of Patients (Health Physics, Vol. 87, No 2, 2004)
  • Guidelines for Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz) (Health Physics Vol. 74, No 4, pp 494-522, 1998)
  • Guidelines on Limits of Exposure to Static Magnetic Fields (1994)
  • Protection of the Patient Undergoing a Magnetic Resonance Examination (1991)
• WHO
  • Static Fields (Environmental Health Criteria Monograph No.232) (2006)

Where to start? In the UK there are currently no exposure limits relevant to MRI set in law.* The Health and Safety Executive in the UK will therefore refer to the national HPA-RPD (was NRPB) and international ICNIRP guidelines when assessing compliance with legislation, and so these documents are most important.

• Patient / volunteer exposure limits: see HPA-RPD 1991.
• Staff and public exposure limits: see HPA-RPD 2004, which aligns to ICNRIP 1998 recommendations regarding public EMF exposure, thus rendering NRPB 1993 obselete.

The MHRA document does not set exposure limits but intends to draw the attention of users to the guidelines for restictions published in the UK by the HPA-RPD and internationally by the IEC and ICNIRP. The MHRA document is an excellent summary, and easy to read. Additionally, it contains HPA-RPD 1991 patient limits which is useful because the HPA-RPD 1991 document is not available for download. The IEC document contains information more relevant to manufacturers.

*Note a new European Union directive which would affect staff exposure limits, which was due for incorporation into UK law in 2008, has been delayed for a number of years pending review.

Some other relevant documents are:

• JMRI Special Issues: Vol 12 issue 1 (2000), Vol 26 issue 5 (2007)
• American College of Radiology (note new 2007 Safe Practices document)
• Criteria for Significant Risk Investigations of Magnetic Resonance Diagnostic Devices (FDA, 2003)
• CDRH MR Working Group Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems (USA, 1997)
• Kanal E et al. American College of Radiology White Paper on MR Safety. Am J Roentgenol 2002;178:1335-47.
• Shellock FG and Crues JV. MR Safety and the American College of Radiology White Paper. Am J Roentgenol 2002;178:1349-52. [Note also Kanal's response.]
• Shellock FG. Magnetic resonance safety update 2002: Implants and devices. J Magn Reson Imaging 2002;16:485-496.
• Kangarlu A and Robitaille PML. Biological effects and health implications in magnetic resonance imaging. Concepts Magn Reson 2000;12:321-359.

This page last updated 2008/03/20.

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