Given the rather spectacular failure mode, isn't this rather a case of "better safe than sorry"? i.e. even if it's technically safe, why not require people to remove everything that triggers the detector just to be sure?
Unlike many facilities, we insist everyone strips down to underpants (no bra) and wears a gown. We push quite hard to remove all jewellery (including piercings), but many places do not.
It removes a whole category of problems, but is also slow, has an extra cost (laundry) and still patients leave things on, covered up by the gown.
But the percentage of people with something in them is very very high.
We are dealing with a population that by definition has health issues, and I’d estimate that 75%+ have something metal in them.
Sternal wires, fillings, clips, biopsy markers, screws, plates, braces, joint replacements (x6), ports, mesh, vascular stent, urinary stents, breast implants.
These are conditionally safe implants from yesterday. If we expanded it to a week we could add heart valves, hearing implants, vsd closure devices and about 20 other implants I’m sure.
We have either memorised or looked up the conditions for each. We pay techs well because we want good staff. Minimum staffing levels include using healthcare assistants and suchlike. There are potential downsides to this approach, particularly around safety.
and still patients leave things on, covered up by the gown
A strong but still relatively weak "test magnet" seems like it might be a good idea to use on patients --- if it has any effect on any metal pieces they're wearing, tell them the MRI is going to pull on it with a thousand times or more force.
