Post-Hurricane Sandy Power Outages Threaten MRI Equipment and Personnel.

For MRI equipment, the greatest threat may not be from the hurricane, itself, but from the extended power outage that will follow Hurricane Sandy.

NASA Image of Hurricane Sandy Before Landfall

Depending upon a number of factors, including the age of your MRI scanners, the volume of liquified cryogen they hold, and the last time they were filled, MRI scanners disconnected from a power source will experience increased boil-off / bleed rates of their cryogen. If water was entrained into the cryogen vent pipes, this means that the water is almost certainly frozen solid, and could partially or fully occlude your vent pipe, depending upon its design. Should the magnet quench (rapid boil-off of a major portion of the on-board cryogen) while the pipe is occluded, the pressure could easily burst the quench vent piping, releasing super-cold cryogenic gas into the occupied space. Other risks of an occluded quench pipe include fatal damage to your MRI scanner, should it quench.

If you have a rooftop cryogen vent discharge that looks similar to the picture below, there is particular risk that wind-driven rain could have entered the quench pipe and may have resulted in quench pipe occlusion.

Quench Pipe Detail (Missing Required Warning Signage) Which Can Be Defeated By 25 mph Wind

If you have a quench discharge similar to the above detail, it is strongly recommended that the MRI equipment vendor or service company inspect the cryogen vent 'elbow' at the MRI scanner at the earliest opportunity for indications of collected water.

Additionally, as hospitals and imaging providers are inspecting roofs and rooftop equipment, be aware of the location and orientation of rooftop cryogen vents. Should the MRI quench (and the pipe is not occluded), massive amounts of super-cold cryogen gas will jet from the cryogen vent pipe. If warning signage and exclusion zone markings were blown away during the storm, make sure employees / contractors working around MRI quench pipe discharges are aware of the hazards and how to protect themselves.

Many newer MRI scanners may last a week or longer without power before quenching, though some models, such as high-field open MRI scanners, may be at risk of quenching in as little as 24 hours of interrupted power. If the liquid cryogen wasn't full before the power outage, or if the MRI has been subject to other thermal stresses (such as water leaking on it), the time before quench may be shorter. Treat each unpowered MRI scanner as you would treat an unknown gun... assume it's loaded and ready to fire unless and until you can prove otherwise.

Bring your MRI equipment vendor and / or any 3rd-party service firm in as quickly as possible. If it looks as though power will be out for the MRI for an extended period, it may be advisable to hook just the refrigeration systems up to a portable generator or other emergency power source to help protect the magnet from quenching.

If you have specific questions about how best to protect your MRI system, building occupants and structure from these risks, please feel free to contact us here at RAD-Planning (contact information below).

(For information on quench pipe protections and preventative maintenance practices, please see the article from an earlier issue of The RADIANT, HERE.)

Please share this alert with any and all hospitals and imaging providers that may be subject to extended power outages. Please use the convenient 'Forward email' blue link below, near the very bottom of this email.