MRI facility design (RTMR)

• The MRI environment has specific safety concerns related to the static magnetic field:
  • Medical devices may malfunction within the static magnetic field, placing individuals with these devices at risk for serious or fatal injury¹
  • Other ferromagnetic items inadvertently taken into the static magnetic field pose a projectile risk and have been known to cause fatal trauma to patients, staff and others^1,2
• In addition to the static field, MRI systems use large liquid helium reserves which, if accidentally released, pose a hazard to those in the vicinity (i.e., potential for asphyxiation and cryogen burns)².
  • MRI system quenches can be dangerous for individuals unaware of the associated risks and the required emergency procedures within the MRI environment
• Controlling access to the MRI environment is instrumental in^1,2:
  • Preventing accidents and reducing risk for serious or fatal injury
  • Ensuring medical devices and MRI scanning systems are not damaged and/or rendered useless
  • Mitigating system downtime and maintaining a safe and effective working environment

• A four zone facility design is used to control and restrict access to the MRI environment².
• The facility is conceptually divided into zones that physically restrict access of health care personnel into areas of danger due to proximity to the static magnetic field²:
  • Zone I – Access to general public for example reception or waiting areas
  • Zone II – Access to unscreened individuals; for example, change and preparation areas
  • Zone III – Physically restricted barrier and consists of areas that have immediate access to the magnet room for example the control room
  • Zone IV – Physically confines the magnet room or areas where the 5 gauss fringe field extends

• Entry to zone III and beyond is authorized ONLY by level 2 personnel*.
  • All individuals entering zone III are under direct supervision of level 2 MRI personnel
• Zones III and IV are locked down when not under direct supervision of level 2 personnel.
  • This restriction is ensured by a physical barrier that is unlocked by key or badge pass
  • Combination locks should not be used, because of the risk a combination could be disseminated to other non-MRI personnel

_{* 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}

• Clear and explicit signage is important to reinforce the safety features of the four-zone design^1,2.
• Recommended signage includes:
  • Clear and permanent demarcation of the 5 Gauss line on the floor in the magnet room
  • Prominent danger signs on the magnet room doors (e.g., “Danger due to the presence of a Strong Magnetic Field, Do not Enter, No Ferromagnetic Objects”)
  • Prominent signage and indicators that indicate the magnet is always on (e.g., a light that is lit at all times, running on back-up power source, accompanied by a sign above or beside door stating “The magnet is Always On”)
  • Signage indicating-MRI zones
  • Zone III and IV require signage which indicates the zone and the restricted access level

• MRI environments are designed to facilitate MRT supervision of Zone IV access from the standard working position at the console.
  • This environment is difficult to supervise and increase the risk of a safety incident
  • Multiple entrances to zone IV are discouraged
• MRI environments are designed to encourage quality patient care:
  • MRTs are able to directly monitor and visualize patients in the magnet bore
  • MRTs are able to hear patients between scans (consideration of types of material used in construction and background noise levels in control room)
• Patient confidentiality is considered by restricting line of sight of patient information on computer screens or desks.