You know what's NOT supposed to be anywhere NEAR an MRI machine when a scan is about to take place?
Any stray metal objects.
AT ALL.
I'm not talking about just magnetic alloys, either. Non magnetically permeable alloys are a no-no, too.
If they are KNOWN and part of the individual, then the scans will account for that. Such as artificial joints, for example.
The intense magnetic fields can act forcefully on magnetically permeable alloys (steel, for example), they can heat various metal alloys, including non-magnetically permeable alloys (copper, brass, etc.), and induce electrical currents in conductors.
This says it all right here:
"Staff had reportedly asked the pair to remove all metal objects before entering the MRI room, as is protocol at hospitals due to the device's powerful magnetic field. However, Novaes decided to go in sans announcing his concealed weapon."