How do X-rays work?

Question: How do X-rays work?
- Keywords:
  imaging,
  x-ray
Asked by anon-292667 on 22 Apr 2021.
- Quentin Leclerc answered on 22 Apr 2021:
  
  Hi Joshua! “X-rays” are a bit like rays of light, except we can’t see them, and they’re not dangerous. To understand how they work, take a bright light (for example, the light of your mobile phone camera), turn it on, and put it under your finger. You should see the light through your finger! However, if you move the light to a thicker part of your body, like your arm for example, you won’t be able to see it anymore. So, the thicker (or more dense) your body part is, the less light will go through.
  X-rays work in the same way! They go easily through skin and organs, but much less through dense things like bones and solid objects. When you do an X-ray examination, we put a screen behind you that measures how much X-rays go through different parts of your body. Then, a picture is drawn, with different bits more or less white based on how much light is getting through. That’s why on the X-ray picture you can see bones clearly – they stop the light from getting through!
- Ed Peake answered on 22 Apr 2021:
  
  1. X-rays are light at a higher frequency generated by firing electrons at a dense metal target.
  
  2. They pass through things depending on how dense they are.
  
  3. Fat/muscle is fat less dense than bone.
  
  4. The x-rays are collected once they have been fired through the persons knee/arm/leg.
  
  5. Then the image is made where fewer x-rays = brighter picture.
  
  For more info see: https://www.nhs.uk/conditions/x-ray/
- Rosie Goodburn answered on 22 Apr 2021: last edited 26 Apr 2021 11:41 am
  
  Quentin and Ed have given really good answers here! I just want to add another way to think about it is that an X-ray picture is actually a shadow! Like your own shadow on the wall from a regular lamp – but it’s a shadow of your bones with the X-rays passing through your more squishy bits!
- Lisa Humphreys answered on 23 Apr 2021:
  
  Agree with Rosie. Quentin and Ed have given great answers. X-rays are very useful for analysing a wide number of objects. Great for using on people in hospitals to help see what cannot be seen by our own eyes.
  
  We use them to give us this deeper understanding of explosives as well. X-ray instruments are used in hospitals, airports and many other research institutions around the world.

Question: How do X-rays work?

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