My father was a panel beater. Before he had an MRI they x-rayed his head in case he had any fragments lodged in his eyes - they can heal over and you don't know they are there. Apparently there have been accidents.
Medical imaging is a marvel of electrical engineering.
What I like to tell friends to consider is this :-
When you are inside one of these instruments, the magnetic fields are
so powerful that they are changing the spin state of every nucleus of
every atom in your entire body.
Including the ones in your brain.
It was a brave engineer who put themselves into the first one to test it.
Amalgum fillings are not affected as the contain no ferromagnetic material
Years ago I used to work with the scientific versions of these in the lab and it was always amusing when newbies would come along, get a little too close and have their credit cards wiped
As gary says, the spin state of atomic nuclei are aligned under the magnetic field pulse and the decay time back to the normal state is measured. This decay time is influenced by different molecular environments, so ultimately (after lots of processing) different tissue/material in the body shows up quite distinctly.
Medical imaging is a marvel of electrical engineering.
What I like to tell friends to consider is this :-
When you are inside one of these instruments, the magnetic fields are
so powerful that they are changing the spin state of every nucleus of
every atom in your entire body.
Including the ones in your brain.
It was a brave engineer who put themselves into the first one to test it.
While I agree with the thought that the engineer was brave to get in there, it had already been tested extensively under its alternate name NMR to determine molecular structures. People get scared when its called Nuclear so for people they changed its name to MRI.
HAd a few to many myself and tend to lean toward Sigma Octanis when I go outside
