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A good N52 neodymium magnet can be 1.5 tesla- MRIs are usually 1.5 tesla. The pull force is around the same too- a steel object will experience say 20g, and 100 lb fishing magnets are not hard to find.

The difference is the size. Even a large magnet only hits that 20g force over an inch or two. An MRI pulls at that force over a full foot or more; equivalent to dropping the object from 20'+. Worse, the MRI starts pulling at 5 or 10 feet away. Objects can experience a tremendous amount of uncontrolled acceleration in fractions of a second.

It's not like a black hole- unless you are trapped under something very large, the crushing force is substantial but not incredible. In fact inside the tube the gradient is actually smaller than the entrance of the tube- you are pulled in strongly, but once inside the tube you are pressed against the wall somewhat less forcefully. Instead it's like an invisible waterfall, and any metal will be swept away in it, fast enough to put holes in you.



Not sure about medicine, but at least in research, most MRI fields are 3T and up.




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