Ever since the 1980s, doctors have been using magnetic resonance imaging (MRI) to peer inside their patients’ bodies without exposing them to ionizing radiation. But there have been trade-offs.
MRI machines explore the body by using powerful magnets and pulsing radio frequency signals. For the magnets to work, MRI manufacturers such as GE use liquid helium to cool them to minus 452 degrees Fahrenheit (minus 269 Celsius), just above absolute zero. At that temperature, they lose all electrical resistance and become superconducting. “When you power up a super-cooled magnet, it can produce the same magnetic field for a thousand years with no more power required,” MR engineer and inventor Trifon Laskaris told GE Reports. The problem is that some machines need as much as 8,000 liters of the helium, and the world is running out of it, to the chagrin of radiologists and party-store owners alike.
This is where Freelium comes from. Freelium is a new magnet technology that is being developed by GE Healthcare. It is designed to allow GE MRI magnets to make do with 1 percent of the helium that conventional MRIs require.
The fact that we are short of helium is quite ironic, considering that it’s the second-most-abundant element in the universe after hydrogen. The shortage is partially self-inflicted. Helium is a waste product of helium-rich natural gas located in deposits stretching from Texas to Montana. In 1925, the U.S. government got into the helium business to secure supplies for defense needs. Helium-filled airships traveled as escorts with supply convoys to Europe during World War II, and demand grew even more during the Cold War and the space race.
After the fall of the Soviet Union, the Helium Privatization Act of 1996 got the government out of the business of producing the gas. But sales from the huge U.S. helium reserve stored in porous rock deep underneath Amarillo, Texas, kept down prices and gave private producers few incentives to enter the market. The shortage followed.
GE started cutting back on helium use back in 1998 when it created a new magnet technology, Zero Boil Off, that kept the helium sealed around the supercooled magnet, recondensed it and recycled it back into the system.
That helped cut down on a portion of the helium required, but it didn’t eliminate the need for a safety exhaust pipe, which leads from the magnet to the outside world and expels the gas in case the magnet fails from something such as a long power outage. Such a failure causes the magnet to go from its superconducting state to a normal state and release a massive amount of energy.
Exhaust systems can range from $5,000 to $250,000 depending on the complexity of the site, and they require a large room for the MRI machine to accommodate the venting system. The Freelium magnet technology, on the other hand, is designed to be in a completely sealed environment, and there is no requirement for an escape pipe. If the magnet fails, the helium could simply be contained inside the magnet. “So imagine how this could help developing countries, like rural Africa and China, who wouldn’t have the funds to build an exhaust system. It is designed to be easier to install and opens access to regions that don’t currently have MRI,” says Stuart Feltham, MR magnet and gradient coil leader at GE Healthcare. It may also help installation of systems in urban areas where siting and venting an MRI are particularly challenging.
The magnet also may make it easier to move MRI machines to far-flung locations and cuts down even more on the amount of helium needed. Normally, MRIs lose helium in transit through evaporation. But because the Freelium magnet is contained, it’s designed so no helium leaks out. A system with a Freelium magnet, once it reaches its destinations, is designed to simply be plugged in and powered up. “This is a much easier process compared to a conventional system,” says Feltham.
“I want the most people out there to be touched by the health-care products we make,” says Feltham. “Making MRI more accessible, either geographically or economically, or to different areas of a hospital, is something we’re extremely excited about being able to provide.”