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A comment on FDA clears ‘world’s first’ portable, low-cost MRI. Parent comment

Re:FDA clears ‘world’s first’ portable, low-cost MRI by refurb on Sunday February 16, 2020 @12:41AM (#22339992)
I have some experience with NMR from a chemistry perspective. The magnetic field is generated through a super conductive coil. Cool it down with liquid nitrogen, generate the current and you have a superconducting magnetic field as long as you keep it cold.

If it warms up, it’s no longer superconducting and all that current starts generating heat which boils the liquid nitrogen off, which can be quite spectacular. Plenty of videos on YouTube.

So yes, turning the magnet on and off is not trivial at all, but as long as you keep it cold, you’re good.

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Re:FDA clears ‘world’s first’ portable, low-cost MRI by kragen on Sunday February 16, 2020 @01:02AM (#22340052)
The ones in hospitals normally use liquid helium, not liquid nitrogen, which accounts for the quench being so spectacular and expensive. The nitrogen just keeps the helium from boiling off too fast.
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Re:FDA clears ‘world’s first’ portable, low-cost MRI by SubiculumCode on Sunday February 16, 2020 @01:08AM (#22340079)
There is a big red button to quench the magnet in emergencies, but it can cost a lot of money to get the MRI going again.
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Re:FDA clears ‘world’s first’ portable, low-cost MRI by ska on Sunday February 16, 2020 @02:03AM (#22340253)
Money and time. I recall one clinical machine that was still not operational I think something like 15 months after unintentional quench. That’s expensive real estate to be sitting idle.
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Re:FDA clears ‘world’s first’ portable, low-cost MRI by markus92 on Sunday February 16, 2020 @02:41AM (#22340422)
15 months is exceptionally long. With a decent support contract, it can all be sorted out in a few weeks.
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Re:FDA clears ‘world’s first’ portable, low-cost MRI by ska on Sunday February 16, 2020 @12:24PM (#22342575)
In theory it can, but depends a bit of damage and the state of your support . I suspect that one was due to arguing about the latter than the former.
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