X-rays and CT Scans

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  • Created by: tiffgrego
  • Created on: 01-04-17 15:25
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  • X-rays
    • Properties
      • short wavelength
      • absorbed by metal and bone
      • turn photographic film balck
      • ionising
      • transmitted by healthy body tissue
      • transverse waves
    • Ionisation
      • x-rays ionise atoms by knocking off electrons
        • all the energy is transferred into the atom
          • this give the electrons so much energy that they move away at high speeds
        • this can kill body cells or lead to cancer
          • it can cause cancer because the loss of elctrons damages DNA causing the genes to mutate and repicate
            • this is difficult to prove
              • there are so many other factors
              • it is difficult to test
                • ethical issues
                • need large numbers
    • Discovery
      • Roentgen was working in a dark room and emitting rays
        • He noticed that a screen was glowing even though there was no visible light hitting it
        • He did tests to find the properties of the rays and named them x-rays
    • Production
      • x-rays are produced by accelerating electrons  and allowing them to collide with a metal target
        • the x-rays are produced when the electrons suddenly decelerate upon collision
        • heated filament emits the electrons by thermonic emission
        • the electrons are accelerated by high voltage
    • Treatment
      • x-rays can be used to kill living cancer cells
        • they have to carefully focused at the right dosage to kill the cancer cells without damaging too many normal cells
        • x-rays are focused on the tumour using a wide beam
          • the beam is rotated around the patient with the tumour at the centre
            • This minimises the exposure of radiation to normal cells (reducing the chances of damaging the rest of the body)
      • not suitable for pre-natal scanning because the radiation can cause mutations to the body and birth defects

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