Ultrasound

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  • Created by: Jo Wells
  • Created on: 21-04-13 12:59
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  • Ultrasound
    • is sound with a higher frequency than humans can hear
      • electrical systems can be made which produce electrical oscillations of any frequency
        • can easily be converted into mechanical vibrations to produce sound waves of higher frequency than the upper limit of human hearing = ultrasound
    • can use oscilloscope traces to find boundaries
      • given the 'seconds per division' setting of the oscilloscope, you can work out the time between pulses by measuring on the screen
        • if you know the speed of sound in the medium, you can work out the distance between boundaries
          • s = v X t
            • s = distance (m)
            • v = speed (m/s)
            • t = time (s)
    • Uses
      • medicine
        • breaking down kidney stones
          • hard masses that can block urinary tract
          • an ultrasound beam concentrates high-energy waves at the kidney stone & turns it into sand-like particles
            • these particles then pass out of the body in the urine
          • is a good method as there's no surgery & = relatively painless
            • an ultrasound beam concentrates high-energy waves at the kidney stone & turns it into sand-like particles
              • these particles then pass out of the body in the urine
        • pre-natal scanning of a fetus
          • ultrasound waves are partially reflected when reach a boundary
            • the exact timing & distribution of these echoes are processed by a computer to produce a video image of the fetus
          • the exact timing & distribution of these echoes are processed by a computer to produce a video image of the fetus
      • medical imaging is full of compromises
        • Safety
          • ultrasound waves are non-ionising & safe
          • x-rays are ionising - can cause caner if over exposed to them
            • not safe to use on babies
          • CT scans use a lot more x-ray radiation than normal x-rays so patient is even more exposed
            • aren't usually used unless really needed
        • Image quality
          • ultrasound images are quite fuzzy - harder to diagnose some conditions
          • x-ray photographs produce clear images of bone & metal - not a lot else
          • CT scans produce detailed images & can be used to diagnose complicated illnesses
            • high resolution images can make it easier to work out problem
            • high quality 3D images can also be used in planning of complicated surgery

Comments

Miss KHP

Good mind map for P3 AQA.

Will help you to compartmentalise everything such as USES and SAFETY.

Once you have completed it, test yourself and check your progress.

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