Maybe it's a lame question but it came up to my mind recently. Usually, Electronic equipment or metallic materials are forbidden in MRI rooms. Also, there are no electric sockets present in that room. How is the machine designed so that it does not rip off itself!!
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2The engineers designed it to not rip itself to pieces? – Jeroen3 Jul 06 '18 at 08:49
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1No doubt made of non-magnetic components. – Robert Endl Jul 06 '18 at 09:00
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TL;DR Magnet is made from nonmagnetic materials where there is high field. Anything sensitive, is positioned where the coil design results in a net magnetic field of zero, where it cancels out. If something is very very sensitive to the field, you can put it in a can, which effectively "pushes" the magnetic field out. Where a magnetic field is zero, components cannot be ripped off.
I know that, a very similar construction, a superconducting lab magnet, is made out from nonmagnetic metals,copper, gold are few.
But, more importantly, you wind a magnet such that its field is confined within the donut, but cancels out outside. this is made from the same current, so it is only a geometric problem, how to wind. I am sure that all electronics are out in the safe zone.
If something should absolutely be shielded from a DC magnetic field, one can use a mumetal can to do so.
A special condition, which is called a magnet quench (shivers down the spine) might make protective winding ineffective for an instant.
If the concern is the magnet itself, then I can say that a lot of mechanical engineering goes into some of the strongest magnets in the world such that they don't collapse onto themselves.
mehmet.ali.anil
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1You could add links to some terms for further reading for the interested reader, like magnet quench. – Andrew Morton Jul 06 '18 at 12:13
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The MRI cannot completely "cancel out" external magnetic fields. There are plenty of cases where things like oxygen tanks fly around the room and kill people. – Scott Seidman Jul 06 '18 at 14:14