MRI Explosion in Philadelphia
Last night we began tracking the development of a story coming from Philadelphia. Yesterday there was an explosion at an outpatient MRI facility operated by Tristate Imaging Group.
Initial reports offer little information, though the damage pictured is consistent with a catastrophic quench breach.
|Reported Explosion at MRI Center
(image from NBC 10 Philadelphia. Click for source.)
Most MRI scanners with rated magnetic field strengths above 0.5 Tesla utilize cryogenic liquids to enable special superconducting elements within the MRI. When liquid helium boils (at a temperature of -269 degrees Celsius, about -452 degrees Fahrenheit), it expands as it warms to ambient temperatures at a ratio of about 760:1. This means that a single liter of liquid helium quickly expands to approximately 760 liters of helium gas. Superconducting MRI scanners typically have the capacity to hold between a few hundred and two thousand liters of liquid helium.
When super-cold helium is released from the insulated and refrigerated confines of an MRI scanner, the gas expands extremely rapidly. If the the expanding helium gas is trapped in an enclosed room, the flashing pressure increase can blow out walls and lift the roof.
Catastrophic quench breaches can be the result of a blockage or failure of the pressure-release mechanisms of the MRI scanner, or if the chimney-like quench-vent is poorly constructed or maintained. These risks can be mitigated through conformance with MRI manufacturers' most contemporary design standards as well as the required periodic inspections of the cryogen venting system.
Apart from the damage to the facility, there is significant risk to individuals from explosively-ejected material, concussive forces, asphyxiation from oxygen depletion, and cold exposure.
While rare, catastrophic quench breaches have damaged MRI equipment, the buildings in which they are placed, and injured people nearby at the time of the explosion.
The next regularly scheduled edition of The RADIANT
is planned to be sent in the next week. If we have any further news regarding the nature of this accident and how MRI providers can protect themselves against similar risks, we will include this in the upcoming issue.
If you have concerns about provisions of your site's cryogen safety elements (or any of the other physical safety and performance elements of your MRI suite), please contact us for information about the RAD-Planning design Peer Review or onsite Physical Safety Review services.