The breakdown of an MR system’s coldhead can be a costly expense. One hospital learned this the hard way when it went one week without realizing that its own was not working. By the time the problem was found, 1,200 liters of liquid helium had been lost, and the scanner’s magnet level dropped to 10%.

The provider ended up spending tens of thousands on a new coldhead and 1,750 liters in replacement liquid helium, according to Sean Mykleby, president of Thermo Magnetics & Cryogen, an independent equipment sales business in Ontario, California that is partially owned and associated with SouthWest Medical Resources (SWMR), which services coldheads, as well as other cryogenic parts.

“A simple remote monitoring service could have prevented an emergency fill, loss of hundreds of liters of helium, and rushed overnight shipping charges. If they’d have had our Helium Zero service, it would have saved them almost $60,000,” he told HCB News.

While often forgotten, components like coldheads, compressors and chillers are crucial for maintaining the proper magnet temperature to ensure scanners are at their peak performance. Breakdowns not only disrupt imaging and workflow but create delays that can pose risks to timely diagnosis for patients.

HCB News spoke with Mykleby, and Turner Hansel, president of Filtrine Manufacturing, which installs and maintains chillers, to discuss the vital roles these components play, and what precautions to take to prevent them from breaking down.

Knowing your MR components
In an MR system, the chiller keeps internal components such as shield coolers and shim coils cool by removing heat from the liquid helium. Options vary based on the specific temperatures they are designed to tolerate. For example, a chiller designed to keep MR scanners cool in 90-degree Fahrenheit maximum ambient conditions will not be able to handle the same heat load when the temperature reaches the triple digits.

This makes extreme heat in the summer a grave concern, as many of these components are located on the outside of MR imaging facilities and are at higher risk of breaking down in these conditions.

“That will cause the coolant supply temperature going to the MR to rise, which will affect the quality of the image and may cause the MR to go down due to high temperature. Or the chiller may fail due to high pressure. Every chiller installation for an MR must have the ability to provide backup cooling to prevent damaging the MR if the chiller fails,” said Hansel, of Filtrine, which is in Keene, New Hampshire.

Chillers should also have freeze protection to prevent ice crystals from forming in the solution. Its breakdown in any way can also lead to coldhead failure. The coldhead keeps temperatures profoundly cold at either 10 degrees or 4 degrees Kelvin, depending on the system, to re-condense helium back into liquid form from gas.

Additionally, as coldheads age, the risk for failure increases, with the component losing around 10% of its cooling capacity each year. This decreases its ability to preserve helium in liquid form, and replacements are recommended every four-to-five years (three-to-four years if using a refurbished product). Replacing a coldhead ranges from $5,000-$10,000, According to Block Imaging, a medical imaging equipment supplier in Holt, Michigan.

Another problem with coldhead aging is that filers and adsorbers can become saturated with impurities, allowing oil to leak into the compressor. Power outages can also lead to oil leaks. Should this happen, the helium will become contaminated, causing the coldhead to fail and cooling capacity to drop, according to Kings Medical Group, a diagnostic medical imaging center of fixed and interim scanners, located in Richfield, Ohio.

If not detected, the breakdown of any of these components will cause the liquid helium to evaporate and the magnet to lose its superconductivity and become quenched. In severe cases, scanners can be out of commission for weeks due to repairs, leading to backlogs and delays in imaging. Additionally, providers are left with hefty repair bills, with severe quenches costing around $50,000 or more to fix. They also must spend thousands to replace the lost liquid helium.

Helium costs rising
The cost of a liter of helium typically ranges from $15 to $30 but has since risen due to ongoing supply chain challenges and the current helium shortage, which is the result of various incidents.

Earlier this year, the Bureau of Land Management, which operates a helium storage reservoir, shut down once for planned maintenance, only to be closed a second time by the Occupational Safety and Health Administration for safety violations. Two brand new helium plants in Russia also were shut down after being damaged in early 2022 by fires.

The U.S. and Russia are two of the largest producers and suppliers of helium. Already a hard-to-find nonrenewable resource, these incidents have made helium even harder to come by and created a shortage that has dealt heavy financial blows to imaging providers.

“All of these events have resulted in supplier allocations of 65% minimum, and liquid helium prices over $50 per liter,” said Mykleby. “We are also dealing with significant inflationary pressures which have been driving up the cost of delivery.”

Supply chain challenges and the great resignation of workers have also created a lack of available parts and personnel for timely maintenance and repairs. To adapt, SWMR adjusted its inventory levels and strategic stocking locations throughout the country, and opened an office in Chicago to oversee engineering, parts warehousing, and parts repair support for its customers.

Hansel says that because of employee turnovers, some HVAC service companies may have to assign tasks like preventative maintenance for chillers and other components to people who are not familiar with the systems.

“This highlights the importance of building redundancy into the chiller and having a good backup cooling program,” he said.

Preventing issues before they occur
The most common reason that chillers break down is poor maintenance, with experts saying that inspections should be conducted at least twice a year, evaluating everything from water quality to glycol concentrations to freeze protection.

Filtrine, for instance, provides new customers with a start-up visit and then three preventative maintenance follow-ups each year. The service agent deployed will evaluate the chiller, clean the condenser, check the fluids and test to see if the pressures, flows, and temperatures are correct.

Additionally, Hansel recommends having backup cooling systems as forms of redundancy for the chiller. For instance, dual independent refrigerant circuits can prevent quenches, because if one circuit fails, the other can continue to operate and keep the coolant at the right temperature.

“The backup cooling can come from city water or building chill water and, depending on the temperature of the water used for backup cooling, you may be able to continue with the daily schedule of scanning and diagnosing patients,” said Hansel.

Proper maintenance also applies to coldheads and compressors. Experts say that the adsorber in a compressor should be replaced once a year to reduce the risk of contamination to the coldhead, and that environmental conditions of the magnet room should be monitored, along with helium levels and vessel pressures.

Additional components must also be replaced in cases where oil gets into the coldhead, including the compressor, flex line and oil separator. Another factor to account for is if there is a positive flow of helium within the coldhead unisock when replacing the coldhead, as air and moisture can cryopump into the unisock, leading to a loss in liquid helium and performance.

One way of ensuring that these components are working properly is to invest in a remote monitoring service. SWMR, for instance, offers a real-time RDU/Helium Zero Service Platform, in which a team of experts remotely monitor these components to identify and alert providers to any maintenance needs or problems.

The solution is offered as part of a $1,200 per month contract that includes labor and expenses, as well as coverage for preexisting conditions. “Being able to know in real time when the chiller or coldhead is off is crucial. Being able to see increased cycling of your cooling equipment or reduced heater duty cycles are just a few parameters that the team at Thermo Magnetics & Cryogen monitors to detect failures of the cooling systems before they actually fail, saving you time, money, and providing peace of mind,” said Mykleby.

He also says that new low volume and self-contained helium magnets are available, as are zero boil-off MRs, which have been on the market for over 20 years. But he warns that even with these solutions, providers should still have precautions in place to detect and address failures immediately.

“Even though these magnets are designed to be zero boil-off, the key to maintain a zero boil-off MR is in the service model you deploy,” said Mykleby. “Having access to real-time data and a proactive service model can essentially eliminate your need for liquid helium.”