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jmvoodoo | 2 years ago

I don't know anything about MRI machines, but couldn't they be built with high temperature superconductors and use liquid nitrogen? If anything this feels like a cost issue not a pure technology issue...

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cyberax|2 years ago

> If anything this feels like a cost issue not a pure technology issue...

It IS a technology issue. High-TC superconductors are basically ceramics, meaning that they are brittle. And a good simulation of MRI experience is being inside a trash can that other people hit with baseball bats.

We are only now starting to get high-TC superconductors in the form of tape, but it's not yet ready to replace low-TC superconductors.

BTW, it's also the reason we're hearing about so many new fusion startups trying to utilize it. It _should_ provide an order of magnitude cost decreases compared to liquid-helium. But it's still something that only startups are using.

fabian2k|2 years ago

The largest NMR spectrometer you can buy today uses high-temperature superconductors and classical ones, but it still cools everything down with liquid helium. As far as I understand you can push more current through the high temperature superconductors when you cool them down more.

NMR spectrometers work on essentially the same mechanism as MRIs, just in a very different form factor. It might even work for MRIs without helium because they have a much lower field (~3-6T) compared to the ~28T of the highest field NMR spectrometer.

The high-temperature superconductors are still pretty new for this field, it took a while to figure out manufacturing them on a scale and quality that could be used for these large magnets.

gclawes|2 years ago

The tape is good enough for fusion reactors but not MRIs?

grogers|2 years ago

I don't know if this is the only reason, but superconuctors have a critical magnetic field that is also related to temperature (higher temp = lower magnetic field). So even if a material is superconducting at liquid nitrogen temperature, that doesn't mean it can produce a strong enough magnetic field for an MRI at that high a temp.

ramraj07|2 years ago

The simpler thing to do seems to regulate helium use in birthday balloons.. not a hard choice between life saving diagnostics and large numerically shaped balloons..

spacebacon|2 years ago

I have 3 foil party balloons still inflated after 2 months and 3 days. I left them by the window as heat from the sun provides kinetic energy to the helium atoms to improve the balloons longevity. These three balloons have provided me with enough joy to keep me inside staring at them all day not outside at risk of injury which ultimately leads to an unnecessary MRI.

macshome|2 years ago

Party balloons are normally filled with what’s known as “balloon gas”. It’s a mix of air and helium that’s not suitable for use in medical equipment.

thsksbd|2 years ago

Why? I like party baloons. My MRI, not so much.

kragen|2 years ago

why don't you fund the life-saving diagnostics enough that they can outbid birthday party planners? i'm not convinced birthday party planners are rich enough anywhere in the world that this is an actual problem

lettergram|2 years ago

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