It’s one of the so-called “noble” gasses. Its atomic number is 2, and it’s both the second-lightest and second-most-abundant element in the observable universe. But despite this abundance, it’s in short supply in places like MRI laboratories. It’s helium.
Since the advent of Magnetic Resonance Imaging in the radiology imaging space, MRI systems have depended on liquid helium to cool the gradient coils. Beginning in 1925, helium users in the United States have obtained their helium from the National Helium Reserve in Texas. But starting in 1996, the federal government decided to begin selling off these helium reserves to save money spent on long-term storage. Many helium refineries have closed over the past decade, and private companies have not moved into the helium refining business. The result is a dwindling supply.
MRI market at special risk
This shortage directly affects the medical industry—especially the MRI market. Facilities with helium storage systems built before the year 2000 are at the greatest risk. These facilities must monitor their helium levels and schedule periodic fills to keep their systems cool. Many of these systems need 1,500 to 1,700 liters of helium to keep the gradients cool. Periodic fills top off the system supply but do not include quenches.
MRI quenches can occur spontaneously or can be controlled. Quenching the system removes the liquid helium and is performed either to ramp the system down or to retrieve a large metal object from the bore. As most radiology directors know, quenches impact both revenue and time. You lose time waiting on a refill and you lose money because the system is not being utilized.
Other refrigeration methods
The sale of helium reserves has made this important product more expensive and scarcer year by year. Elements that drive pricing include the location where the helium is refined and the costs associated with transporting it to your site. Since the turn of the 21st century, MRI vendors have introduced other refrigeration methods to cool the gradients that include some helium. These MRI systems are considered zero boil-off, meaning that they do not require vast amounts of helium to be put back in on a regular basis. Depending on the vendor, these systems can go at least 10 years before needing a fill. Meanwhile, vendors continue to consider developing other ways to more efficiently cool their systems.