Len Spooner's organization MagnaServ, though founded less than a decade ago, has become a leader in servicing MRIs. The company's core competencies focus on GE Medical MRI and CT systems.

Like Oxford Instruments which provides electronics and magnets with liquid helium supplies and Praxair which specializes in helium but also offers service, MagnaServ provides comprehensive services offering a range of electronics, magnets and liquid helium supply to its customers.
Over the last decade, improvements to the designs and specs of MRIs ensure they require less helium and have reduced boil-off; however the problem has not disappeared. Mark Glajchen, head of Liquid Helium & Associated Services, Linde Inc. reports that during the evolution of the machines manufacturers have utilized a nitrogen shield and a vacuum, and in the most modern machines, a vacuum and a refrigeration system known as a cold head. Unfortunately, it can't be completely insulated. There is some transfer of energy which can cause a heating leak into that liquid helium, which results in some boil off, which eventually requires some replenishment of the product.

Scott Murray, VP/GM Magna Group, Philips MR has been in cryogenics for more than 30 years, he offers some insight into the improvements that have helped to lower helium consumption. "In the '90s helium use was .1 to .2 liters per hour. Since replenishment of helium was not efficient, about 75% of the helium transferred," says Murray. "The industry then converted to more efficient 1.5T MRs which would lose .03 to .05 liters per hour, or less than half of what occurred before. Boil off went from 1600 to 500 liters per year."

Still, that's a far cry from later improvements. "The industry adopted a 4-Kelvin registration which allowed a system to re-condense the boiling helium and put it back into the magnet. So, technically, the boil-off became 0%," says Murray. "That does not mean the need for helium servicing is eliminated as there is still some loss due to downtime for servicing the cryo-cooler. This is device dependant and could be one time per year or one time per three or four years."

"One of our biggest problems when some customers hear 'zero boil-off' is they don't align themselves with a service company," says Dave Baldwin. "If they have a situation where they lose power, or some other emergency, they are scrambling to make arrangements for a liquid helium fill. It's great when the zero boil-off works, but people need to still monitor for leakage and have plans set and know the right actions to take in case any problems occur."

More Industry Reports