An ultrasound is a tool used to take a picture. A sonogram is the picture that the ultrasound generates. Sonography is the use of an ultrasound tool for diagnostic purposes.
The basics of ultrasound: An electric current passes through a cable to the transducer and is applied to the crystals, causing them to deform and vibrate. This vibration produces the ultrasound beam. The frequency of the ultrasound waves produced is predetermined by the crystals in the transducer. (See: https://www.vetfolio.com/learn/article/basic-principles-of-ultrasonography)
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