Using A Medtronic O-Arm with a Broken Hand Switch
Dave Yoder: December 12, 2024
If you own or operate an MRI you're well aware of the dreaded "Q word". In case you're not, we'll say it just once, quietly. Okay? Here goes: quench.
Like nails on a chalkboard, right? But, on the bright side, now we can get to the nice part of the blog where I give you a strategy to help keep your magnet away from the Q word. One simple phrase, "cold head replacement."
The Cold Head
Inside your MRI, there's a cooling system with hundreds of liters of liquid helium that is keeping the magnet cool. As this helium takes on ambient heat, it changes into gas. Inside that cooling system there is a part called a cold head that re-condenses that helium gas to prevent it from boiling off entirely.
The measure of the cold head’s performance is called its "recondensing margin." A healthy range should be recommended in your system's OEM documentation. The metrics for this number can be found in the system’s console.
Warning Signs
If the recondensing margin fluctuates or falls while the compressor is working properly, this could be a red flag that the cold head is not doing its job effectively.
While overall helium levels may not drop initially (which can lead you to believe nothing is wrong) this issue is really like a ticking time bomb. Once the helium margin drops to zero, the helium begins burning off at a rate that increases exponentially. Without healthy helium levels, the magnet is not properly cooled. This affects the homogeneity of the magnet and overall image quality. Excessive helium boil-off will also drastically increase the system’s risk of dropping a Q word on you.
If your cold head is banging or making odd noises, it might have a mechanical problem; another sign it needs to be replaced.
How old is your Cold Head? Each cold head will see unique levels of usage, but in our experience as a provider of MRI equipment and parts, and the experiences of our engineers and partner hospitals, we've found that the typical longevity of a cold head is as follows:
- Refurbished: 3-4 years
- New: 4-5 years
If the date label on your cold head reads within these ranges, it's time to start planning for a replacement.
What to Do
Once the recondensing margin reaches zero, we suggest you replace the cold head within the week. The longer you wait, the higher the risk. The best solution: replace your cold head sooner rather than later!
If you have other questions about MRI service and replacement parts, we're here to help you get in the know. Contact us to learn more or, if you need a cold head today, request on with the button below.
