This is why if/when I require MRI on my head (had to due to a major concussion back back in the 00's)...i answered YES to the question "Have you ever worked around metal filings, grinders etc?" or something to that effect. They take you into xray and do a couple of films of your head before they put you in the whirrryspinnytechnomusic thing, to make sure you dont have a stray metal filing in/around an eye, sinus cavity, etc....
Those do bad things to your eyeballs and headballs once they get the juice....