MRI Safety Standards and Guidance

Listed below are some international and national (esp. UK and Australasia) MR safety standards and professional guidance documents. They are listed alphabetically.


ACR Guidance Document on MR Safe Practices: 2013, American College of Radiology Expert panel on MR Safety

Kanal et al. Magn. Reson. Imag. 37:501-530.

Link: https://www.acr.org/Clinical-Resources/Radiology-Safety/MR-Safety

Status: US-based professional guidance.  2019 Updates and Critical Information.  Journal of Magnetic Resonance Imaging https://doi.org/10.1002/jmri.26880.

Summary: The ACR Guidance Document on MR Safe Practices: 2013 addresses numerous MR safety-related topics such as:

  • Static magnetic field-related issues such as translational and rotational forces on ferromagnetic materials
  • Time-varying magnetic field-related issues such as induced voltage, auditory considerations and thermal issues
  • Personnel qualifications and training
  • Site access restrictions
  • Pregnancy-related issues
  • Guidelines on claustrophobia, anxiety, sedation, analgesia and anesthesia
  • Safety of MR scanning of device patients, such as patients with cardiac pacemakers, implanted auto-defibrillators, etc.
  • MR siting considerations
  • Emergency preparedness planning.

American Society for Testing and Materials (2013) ASTM International F2503-13 ‘Standard practice for marking medical devices and other items for safety in the Magnetic Resonance Environment.’

Link: https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm107708.pdf

Status: Applies internationally as IEC 62570:2014.

Summary: This international standard applies to the practice of marking of items that might be used in the magnetic resonance (MR) environment. The purpose of this practice is to mark items that might be brought into the MR environment and to recommend information that should be included in the marking. The standard specifies the permanent marking of items, which are used in an MR environment, by means of terms and icons.


ARPANSA (1991) Safety guidelines for magnetic resonance diagnostic facilities RHS 34.

Link: https://www.arpansa.gov.au/regulation-and-licensing/regulatory-publications/radiation-health-series

Status: withdrawn, replaced by “Trusted International Standard”: International Commission on Non-Ionising Radiation Protection (2004) ‘Medical Magnetic Resonance (MR) Procedures: Protection of Patients.’ Health Physics 87:197-216.

Summary: See ICNIRP guidelines below.


ARPANSA RPS-3 Maximum Exposure levels to Radiofrequency Fields 3 kHz-300 GHz, 2002

Link: https://www.arpansa.gov.au/sites/g/files/net3086/f/legacy/pubs/rps/rps3.pdf

Status: Applies to Australia. Updated 2016. Deals with occupational and public exposure.

Summary: Basic restrictions on spatial peak SAR, in the head and torso and in the limbs, are intended to prevent excessive localised temperature rise in tissue. These limits do not apply to patients.


AS/NZS 3200.2.33 (2005) Medical electrical equipment Part 2.33: Particularrequirements for safety- Magnetic resonance equipment for medical diagnosis.

Link: https://www.saiglobal.com/PDFTemp/Previews/OSH/AS/AS3000/3200/3200.2.33-2005.pdf

Status: Same as IEC 60601-2-33 2002, obsolete but still the official Australian Standard. Modern MR scanners conform to IEC 60601-2-33 Edn 3.2, 2015. See below.

Summary: Similar to Edn 3.2 but with outdated exposure limits and other obsolescent information.


FDA Criteria for Significant Risk Investigations of Magnetic Resonance Devices

Link: https://www.fda.gov/media/71385/download

Status: Non-binding recommendations for the USA.

Summary:  Sets guideline exposure levels indicating significant risk to adults, children and neonates for the purposes of determining whether a clinical study requires Agency approval of an Investigation Device. Exemption (IDE). Levels are:

  • 8 T, with 4 T for younger neonates;
  • whole-body SAR not exceeding 4 W kg-1 averaged over 15 minutes
  • head SAR not exceeding 3.2 W kg-1 averaged over 10 minutes;
  • avoidance of discomfort or painful PNS from gradient dB/dt;
  • acoustic noise level not exceeding 140 dB(Z) unweighted or 99 dB(A) rms (A-weighting).

FDA: Establishing Safety and Compatibility of Passive Implants in the Magnetic Resonance (MR) Environment, Guidance for Industry and Food and Drug Administration Staff

Document issued on December 11, 2014.

Link: https://www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm107708.pdf?source=govdelivery&utm_medium=email&utm_source=govdelivery

Status: US-based guidance. The updated document supersedes the previous release from August 21, 2008 and is focused on passive implants that function without electronic power.

Summary: This guidance addresses testing and labeling of passive implants for safety and compatibility in the magnetic resonance environment. Testing methodologies and standards are referenced. Active implants or devices that are not implants do not fall within the scope of this guidance.


Health Protection Agency: Protection of patients and volunteers undergoing MRI procedures’ Documents of the Health Protection Agency. RCE-7 (2008)

Link: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/329364/Protection_of_patients_and_volunteers_undergoing_MRI_procedures.pdf

Status: Current UK guidance on exposure limits and bio-effects.

Summary: Similar to ICNIRP guidance. Useful as supplementary material.


International Commission on Non-Ionising Radiation Protection (2004)Medical Magnetic Resonance (MR) Procedures: Protection of Patients.

Health Physics 87:197-216.

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPMR2004.pdf

Status: Voluntary international guidance. Replaces ARPANSA RHS 34. The document is intended for use by international or national medical device regulatory authorities, MR users and health professionals, and those involved in the design and manufacture of MR equipment for clinical applications. Contraindications, precautions, and safety considerations for patients are given.

Summary: Contains a detailed review of biological effects of static, time-varying gradient and RF magnetic fields, acoustic noise, and special cases arising from disease or medication, childhood and pregnancy. Patient exposure limits reflect those contained in IEC60601-2-33, 2001) and are now superseded by the 3rd edition Amendment 2 of that standard. There is a section on research volunteer scanning and use of the 2nd Level (Experimental Mode) plus practical guidance on operational and magnet safety issues.

The Amendment to the ICNIRP StatementMedical Magnetic Resonance (MR) Procedures: Protection of Patients.’ Health Physics 97(3):259‐261; 2009

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPMR2009.pdf

Status: Voluntary international guidance. Applicable in Australia as an update on ARPANSA RHS 34.

Summary: This amendment increases the normal mode static field limit to 4T, the first level to 8T and second level to greater than 8T.


ICNIRP Guidelines on Limits of Exposure to Static Magnetic Fields

Health Physics 96(4):504‐514; 2009

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPstatgdl.pdf

Summary: Sets a 2T limit but for specific work applications, exposure up to 8 T can be justified, if the environment is controlled and appropriate work practices are implemented to control movement-induced effects. This brings it in line with current IEC limits.


ICNIRP Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields from 1-100kHz.

Health Physics 2010; 99: 818-836 and Erratum Health Physics 2011; 100: 112

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPLFgdl.pdf

Status: International guidance on occupational and public exposure. Non-binding. ARPANSA limit (RPS 3) covers range above 3 kHz.

Summary: International guidance on occupational and public exposure in the range 1 Hz- 100 kHz. Limits are different from IEC MRI-based limits. See appendix.


ICNIRP Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz).

Health Physics 74:494 –522; 1998.

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPemfgdl.pdf

Status: International guidance on occupational and public exposure. Non-binding. ARPANSA limit (RPS 3) covers range above 3 kHz.

Summary: Covered by ARPANSA RPS-3. Limits are different from IEC MRI-based limits. See appendix.


ICNIRP Guidelines for Limiting Exposure to Electric Fields Induced by Movement of the Human Body in a Static Magnetic Field and by Time-varying Magnetic Fields below 1 Hz

Health Physics 106(3):418-425; 2014

Link: http://www.icnirp.org/cms/upload/publications/ICNIRPmvtgdl_2014.pdf

Status: International guidance on occupational and public exposure. Non-binding.

Summary: Reviews acute sensory effects arising from movement within the static magnetic fringe field gradient. Proposes a reference level of 2.7 Ts-1.


International Electrotechnical Commission:  IEC 60601-2-33 Medical electrical equipment – Part 2-33: Particular requirements for the basic safety and essential performance of magnetic resonance equipment for medical diagnosis, Edn 3.2, 2015

Link: https://webstore.iec.ch/publication/22705

Status: Current. All MR equipment manufacturers comply with its requirements.

Summary: A highly technical document in English and French. Contents include:

  • Modes of operation
  • Safety instructions
  • Standardised methodologies on the measurement of scanner safety-related parameters: B0 fringe field, dB/dz fringe field spatial gradient, dB/dt rate of change of gradient fields, SAR specific absorption rate, B1+rms RF excitation field
  • Compatibility data specifies field measurements that must be made available to customers, required to assess implant conditions and occupational exposures
  • Extensive scientific background and references in the Annex
  • Exposure limits for patients and workers
  • Signage specifications
  • The fixed parameter option FPO:b via standard TS10974[1], as a means of determining active implant safety in the MR environment.

The Inter-Society Working Group on MR Safety: Recommended responsibilities for management of MR safety

Fernando Calamante, Bernd Ittermann, Emanuel Kanal, The Inter-Society Working Group on MR Safety, and David G Norris.

J Magn Reson Imaging. 2016 Nov; 44(5):1067-1069

Link: http://onlinelibrary.wiley.com/doi/10.1002/jmri.25282/epdf

Status: Guidance from the International Society for Magnetic Resonance in Medicine, Section for MR Technologists, European Federation of Organisations for Medical Physics, European Federation of Radiographer Societies, European Society of Radiology, European Society of Magnetic Resonance in Medicine and Biology.

Summary: Defines the roles and responsibilities of MR Medical Director (MRMD), MR Safety Officer (MRSO), MR Safety Expert (MRSE).


ISMRM Safety Committee: MR system operator: Recommended minimum requirements for performing MRI in human subjects in a research setting

Calamante et al. J. Magn. Reson. Imaging 2015;41:899–902.

Link: http://onlinelibrary.wiley.com/doi/10.1002/jmri.24717/epdf

Status: Learned Society guidance.

Summary: This article is intended to provide guidelines for the minimum level of safety and operational knowledge that an MR system operator should exhibit in order to safely perform an MR procedure in a human subject in a research setting.


Medicines and Healthcare products Regulatory Agency (MHRA): Safety Guidelines for Magnetic Resonance Imaging Equipment in Clinical Use.’ MHRA DB2007.

Link: https://www.gov.uk/government/publications/safety-guidelines-for-magnetic-resonance-imaging-equipment-in-clinical-use

Status: Current UK guidance. Non-binding, standard practice.

Summary: A highly practical and comprehensive publication covering most aspects of MR safety including installation and cryogen handling. References to UK legislation, but this does not negate the value of the guidance. Available free, and highly recommended.


National Electrical Manufacturer’s Association

Link: https://standards.globalspec.com/std/10149021/nema-ms-12

Status: Industry standard for MR manufacturers.

Summary: industry consensus methodologies on measuring MRI system performance. Whilst they deal primarily with image quality, Standards MS 4, 8 and 10 are relevant for patient safety:

  • NEMA MS 4 – Acoustic Noise Measurement Procedure for Diagnostic Magnetic Resonance Imaging Devices [26];
  • NEMA MS 8 – Characterization of the Specific Absorption Rate (SAR) for Magnetic Resonance Imaging Systems [27];
  • NEMA MS 10 – Determination of Local Specific Absorption Rate (SAR) in Diagnostic Magnetic Resonance Imaging Systems.

Royal Australian and New Zealand College of Radiologists: MRI safety guidelines version 2.0, 2017 

Link: https://www.ranzcr.com/college/document-library/ranzcr-mri-safety-guidelines

Status: Current guidance from the Faculty of Clinical Radiology. Best practice, non-binding.

Summary: Covers the practical, organisational and training aspects of MR safety in the clinical setting. The roles of MR Medical Director, MR Safety Officer and MR Safety Expert are referenced. Exposure limits are consistent with the current IEC standard. Procedural guidance provided with regard to passive and active implants. The guidance on the use of gadolinium-based contrast agents has been updated by a separate RANZCR statement (see below).

RANZCR Statement on Gadolinium Retention, July 2017

Link: https://www.ranzcr.com/whats-on/news-media/171-ranzcr-statement-on-gadolinium-retention

Status: current guidance.

Summary: Advice on the use of gadolinium-based contrast agents following reports of long term retention in the brain and other organs. See also the statement from the Therapeutic Goods Administration: https://www.tga.gov.au/alert/gadolinium-based-contrast-agents-mri-scans. 


 

[1] ISO/TS 10974:2012 is applicable to implantable parts of active implantable medical devices (AIMDs) intended to be used in patients who might undergo a magnetic resonance scan in 1.5T, cylindrical bore, whole body MR scanners for imaging the hydrogen nucleus. Link: https://www.iso.org/standard/46462.html

 


Leave a Reply