Washington University’s Magnetic Resonance (NMR and MRI) Safety Program ensures appropriate practices and procedures are in place to maintain a safe work place around magnetic fields.  The EH&S Radiation Safety Office maintains an inventory of all MRI units used for research on campus, and can provide help in setting up your safety program.  If you know of an MRI or large magnet that Radiation Safety may be unaware of, please let Radiation Safety know.

If you cannot find the information you are looking for in the sections below, please contact the Radiation Safety Office at 314-362-3476 or radsafety@wustl.edu.

Room Postings Required For MRI
All entrances must be posted with an appropriate warning sign for areas that exceed 5 gauss that mentions the hazards for pacemakers and other metallic implants.   Other warnings for Magnetic Media and ATM/Credit cards are recommended at the 10 gauss level.   A warning about potential projectiles from tools and equipment is needed at the 30 gauss level.
The 5 Gauss Line
This line specifies the perimeter around a MRI scanner within which the static magnetic fields are higher than 5 gauss.  5 gauss and below are considered ‘safe’ levels of static magnetic field exposure for the general public.  Even if the 5 gauss line is inside the bore, you must still post the area with the appropriate signage to warn of hazards that are present.
MRI Training
Anyone who will need to cross the 5 gauss line must have awareness training at a minimum.  If the worker does not cross the 5 gauss line, the only training needed is to be able to recognize the door postings.  In general, training is provided by the principal investigator overseeing the MRI unit.  Please contact Radiation Safety at 314-362-3476 for more information.
Room Postings

All entrances must be posted with an appropriate warning sign for areas that exceed 5 gauss that mentions the hazards for pacemakers and other metallic implants.   Other warnings for Magnetic Media and ATM/Credit cards are recommended at the 10 gauss level.   A warning about potential projectiles from tools and equipment is needed at the 30 gauss level.

Personal Protective Equipment (PPE)

No PPE is required for MRI protection, but universal precautions are recommended.

Protective Barriers

Metal detectors at the entrance are recommended if not specifically required by the manufacturer and/or owner/operator.

Quenching

There is a rare possibility that the liquid helium will suddenly become gaseous.  This can occur if the superconductor becomes ‘normal’ resulting in the dissipation of heat and evaporation of cryogens.  An appropriate exhaust system should already be attached to the magnet so that in the event of a quench, the gases will be vented to the outside and the helium does not become an asphyxiation hazard.   If the exhaust system fails, the patient must be removed very quickly.  An emergency procedure should be established to facilitate their removal.

The only time you should manually quench an MRI unit is in an emergency where the life of an individual is at risk.   If someone is trapped but not seriously injured do not quench the unit without approval of the MRI responsible individual.   If a piece of equipment is stuck to the unit you must contact the MRI responsible individual before attempting to retrieve the item.

Who may operate an MRI?

Only trained operators shall operate an MRI unit and must control access to the MRI suite and perform individual assessment of anyone prior to allowing access to any area that is beyond the 5 gauss line.