• Question: How do ultrasounds work?

    Asked by anon-195808 to Gill on 27 Jan 2019. This question was also asked by anon-195798.
    • Photo: Gill Harrison

      Gill Harrison answered on 27 Jan 2019:

      The transducer (hand held probe) has lots of tiny crystals at the face of it. An electrical signal is passed over these crystals and that converts the signal to high frequency sounds waves. Theses sound waves pass into the body (we need to use the gel to allow the signals to pass though to the inside of the body, as sound can’t travel through air).
      The sound bounces off various structures / internal organs and some of the sound waves will return to the transducer. Once it returns the sound waves are converted back to electrical signals, which are then displayed as black, white or grey dots on the screen. These make up the ultrasound image. The user (in my case I’m a sonographer) will then interpret whether these look normal for that organ or abnormal. This can then help to make a diagnosis.

      This might be a good place to start, it’s a 60 second video:

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