Question: How does a x-ray work? How can it see inside your body?

James Martin answered on 15 Mar 2017:

X-rays are basically very high energy light particles. When normal light travels through your body, it very quickly is absorbed and the energy dissapated (hence why you’re not see-through!). X-rays don’t behave like that. They mostly travel all the way through, only some are stopped as they move through the body. Using maths, if you know how how many x-rays left the source, and can measure how many went through the body, you can calculate how much ‘stuff’ it went through. The less that gets through the body, the more dense (e.g. bone) the body-part was.

So, the x-rays leave the source, pass through the body, and the brightness of what passes through to the receivers (on the other side of the body) gives you your picture.