From the October 2014 issue of HealthCare Business News magazine


“Once energized, you can take away the power supply and the electrical current keeps going without any resistance and it remains there for years and years and years,” says Marshall. In deep space, a superconductive magnet would work without a source of power because it’s already cold enough. According to Marshall, some satellites exploit these properties on their journeys through the cosmos.

The watchful eye of remote monitoring
Knowing the status of the helium in an MR scanner is essential for nmaintaining the system, avoiding downtime, and preventing costly situations. Remote monitoring is one solution to that dilemma. HCBN spoke to David Schuetz, director of service business management MR for Siemens Healthcare, about Siemens Remote Services.
Schuetz and his colleagues monitor shield temperature, water temperature, helium levels, and chiller water flow rates over a secure network established between their service center and the facilities using their MR systems, (HCBN will provide extensive coverage of chillers in our November issue). “With regards to helium monitoring, we’re looking specifically at the cooling system parameters,” says Schuetz. “We’re looking at the health of the cold-head, we’re looking at pressures inside the magnet, and with those parameters, we can tell the overall health of the cooling system.”

Historically, magnets were kept at 10 degrees Kelvin but today, most new MR magnets are 4 degrees Kelvin. That colder temperature means less helium is boiled off and doesn’t need to be topped-off as often.

“The 4k systems operate within a very small tolerance of helium level fluctuation,” says Schuetz. “So if you have a 4k system that has been working perfectly for five years, and there’ve been no power interruptions, and the chilled water has been functioning right, and the system has been operating exactly the way it should be, you’ll notice zero boil off.” But, Schuetz says, environmental situations may result in minor boil off here and there, and remote monitoring can limit that impact.

As an alternative to OEM remote monitoring, some end-users opt for independent monitoring services, such as that provided by Cool Pair Plus. HCBN spoke to Ron Schultz, the company’s field service manager, about the kind of problems one might have with magnets and helium. “In the majority of service calls received, the report is that the cold-head and compressor are not working,” says Schultz.

“First question asked is if there have been any chiller or power issues at the site. If so, there is a list of questions to determine if it is indeed a cold-head or compressor issue or a site chiller issue,” says Shultz. Poor coolant flow and high temperature will cause issues with the helium compressor and cold-head.

October 2014 Magazine

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