Tim Dodge
They say it took an hour to free him… Someone decided to use the standard shutdown instead of the emergency shutdown that only takes a few seconds…
MRI rapid shutdown: emergency procedures and safety
An MRI rapid shutdown, also known as an emergency quench, is a critical procedure to quickly de-energize the strong magnetic field of a superconducting MRI machine.
Here’s why and how it’s done
Life-threatening emergencies: The primary reason for a rapid shutdown is a life-threatening emergency, such as a patient being trapped or pinned to the magnet by a metallic object.
Safety risks: The powerful magnetic field of an MRI attracts ferromagnetic objects, which can become dangerous projectiles. In a fire or other disaster, a rapid shutdown allows emergency responders to safely enter the room without the risk of being drawn into the machine.
Quench procedure: The emergency shutdown is initiated by pressing a dedicated “Magnet Stop” or “Emergency Rundown” button, typically a large red button located on the external wall of the magnet room.
Helium release: This action triggers a process called quenching, where the liquid helium that cools the superconducting magnet rapidly boils off and is vented outside the building through a quench pipe.
Potential dangers: While essential for safety, a quench can be dangerous. The rapid release of helium gas can displace oxygen, creating a risk of asphyxiation if the gas is not properly vented. It can also cause frostbite due to the extreme cold of liquid helium.
Cost and damage: A quench is an expensive procedure, both due to the loss of the costly liquid helium and the potential for damage to the MRI system’s superconducting coils.
Important Note: Rapid shutdowns are a last resort and should only be initiated in genuine emergencies after carefully assessing the situation.