Question: how does a MRI mechene work

Andrew Scott answered on 15 Jun 2015:

It’s a good question to ask your physics teacher, but this is a short answer.

You’re body is mostly made of water, which is two hydrogen atoms and one oxygen. The hydrogen atoms have a nucleus, which is one proton. When you put those protons into a magnetic field, they have a property known as “spin”, which makes them spin in the magnetic field. If you then send radio waves in at the right frequency, some of the radio waves are absorbed by the protons and a little while later, the protons send radio waves back out. So, the MRI machine is a massive doughnut shaped magnet (between 1.5 and 7Tesla). It’s so strong that, we can’t take iron objects anywhere near the scanner, because they turn into dangerous projectiles! (Google: floor polisher MRI). You lie inside the big magnet and we send radio waves in. Then we detect the radio waves coming back out and, by knowing where they come from inside your body, create pictures of the insides of your body. It doesn’t use x-rays or any radioactive substances, so in many ways it is much safer than x-ray or CT.