Why Is Helium Used in MRI Machines?

Helium is used as a cooling agent in MRI machines (in liquid form) because of its extremely low boiling point. This fluid keeps superconducting magnets at temperatures of around -269°C (-452.2°F) to enable proper imaging function.

In this guide, we explain how helium does this and why no other fluid can match its properties and benefits in imaging technologies. You will then learn how different advancements have addressed helium-related safety concerns.

Helium Plays a Critical Cooling Role in MRI Technology

In an MRI machine, helium works similarly to the coolant in a car’s engine – though it is way more extreme. 

Without it, the whole MRI system would overheat and fail.

This is because the superconducting magnets in MRI machines need to maintain incredibly cold temperatures to function properly – and those temperatures are achieved through the use of liquid helium.

Once the magnetic coils reach the right temperature, they become superconducting. In other words, helium-cooled magnets can conduct electricity with virtually zero resistance.

This super-cooling process lets magnets generate the powerful magnetic fields necessary for detailed images of the human body.

Why Helium is Irreplaceable in MRI Machines

Helium is expensive, so many people wonder why we can’t use a more cost-effective cooling agent. 

It’s because helium has the lowest boiling point of any element on Earth – this makes it the only practical choice for achieving the extreme temperatures needed for MRI machines.

Interestingly, helium is the only element that cannot be solidified by lowering its temperature at normal atmospheric pressure. That’s why helium is so useful when you need something extremely cold – like in MRI machines.

Traditional MRI machines use about 1,700 liters of liquid helium to maintain extremely low temperatures (which is enough to fill about 10 bathtubs). Small amounts of helium used in MRI machines naturally evaporate over time, so it needs to be topped off periodically.

Further Reading: What Is Helium Used for in Hospitals?

Safety Features of Modern MRI Machines

As helium is a non-renewable resource that should be approached carefully because of its properties, modern MRI technology has come a long way in addressing safety concerns and helium conservation.

For example, when helium suddenly boils off (also known as a quench), it rapidly expands into a gas that can displace oxygen in the room.

This sudden expansion is so powerful that it’s comparable to a small explosion, which is why strict safety protocols are critical in MRI facilities. New MRI systems are designed with safety features that direct this gas safely outside the building, protecting patients and staff.

Helium Efficiency Advancements in MRI Systems

Now there are MRI systems that use less than 1% of the helium typically required in traditional systems.

This reduction comes from a shift in design: instead of submerging the magnet in a large bath of liquid helium, modern systems use a sealed, vacuum-insulated chamber with just a small amount of helium, kept cold by a mechanical cryocooler.

If you’re thinking – that sounds a little too good to be true – then you are right: these systems can have higher upfront costs and repairs can be more complex if the cryocooler fails.

Choosing the Right Helium Supplier

It’s hard to overstate the importance of helium in MRI systems – without it, we wouldn’t have access to one of the most powerful diagnostic tools.

Whether you’re running a traditional high-field MRI or one of the newer reduced-helium systems, having a dependable supplier helps prevent unexpected downtime for your MRI machine(s).

Further Reading: What Is Helium Used For?