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Prevention of missile accidents (MRI specific)


Measures such as screening, labelling, and restricting access are used to prevent the entry of potential projectiles into the MRI environment


+ Screening

  • MRI facilities employ strict policies to ensure screening procedures are implemented for the detection of potential projectiles prior to their entry into the MRI environment.
    • All individuals entering the MRI environment are screened before each procedure (regardless of whether they have been screened in the past), according to their MRI personnel level
    • All equipment is verified for MRI safety before being allowed into the MRI environment by a Level 2 MRI Technologist*
    • Additional attention must be given to objects made from conducting materials, as these may pose hazards under certain conditions1

* Level 2 MRI personnel are defined as those with MRI safety education to ensure safety of all individuals and facility resources within the MRI environment

+ Preparatory measures

  • The most effective means to prevent a patients carrying in potential projectiles is to have them change out of street clothes into hospital gowns.1
    • MRI-safe hospital gowns are used (those made of cotton, without pockets and without metal snaps)
    • Other forms of clothing may contain metallic threads, objects, or synthetic materials that pose a danger during the MRI exam1


  • Non-ambulatory patients may only enter the MRI environment in an MRI-safe wheelchair or gurney which has been inspected specifically for:1
    • Ferromagnetic oxygen tanks and IV poles1
    • Sandbags with metallic contents2
    • Ferromagnetic objects concealed under blankets, in pockets or folds of clothing or stowed on transport equipment1


  • The MRI fringe field is clearly demarcated and secured by trained staff.1,3

+ Labelling

  • Equipment and objects are labelled according to the ASTM (formerly known as the American Society for Testing and Materials) standards for safety in the MRI environment as follows:4
    • MRI safe – objects that pose no known hazards in all MRI environments
    • MRI conditional – objects that are safe when used in a specific manner within specific MRI environments, with limitations on usability or the testing that was performed on it
    • MRI unsafe – objects that pose a known threat or hazard in all MRI environments


  • A list of MRI safe and MRI conditional objects is maintained in the department, including details of restrictions for use.
    • Information not contained within the document can be obtained from the manufacturer’s guidelines for use in MRI environments

+ Staff education

  • All MRI staff and other personnel who may enter the MRI environment are provided with formal training at regular intervals on MRI safety, including:1
    • Discussion of objects that can and cannot be allowed into the MRI environment3
    • The importance of effective screening1
    • A reminder that the magnetic field is always ‘on’1

+ References

  1. Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices. 2012 Ed. Los Angeles, CA: Biomedical Research Publishing Group; 2012.
  2. ECRI. Sandbags: may contain metal, posing hazard in MRI environment. Health Devices Alerts Action Item. Accession Number: A7418. Plymouth Meeting (PA):ECRI; 2006 Jul 14.
  3. Kanal E, et al. American College of Radiology White Paper on MRI safety. AJR 2007;188:1–27.
  4. George Mason University, Krasnow Institute of Advanced Study. MRI Suite Safety and Operations Policies and Procedures Manual. January 2010. Available at: Accessed February 21, 2013.

Related guidelines



April 18, 2013


Canadian Association of Medical Radiation Technologists
85 Albert St, Suite 1000, Ottawa, ON, K1P 6A4
phone: 613 234-0012 / 800 463-9729
fax: 613 234-1097