How does ultrasonography work?

Question

And what does the gel contribute to it?

In: 1

Answer 1

Ultrasound is sound at a higher frequency than humans can hear. It has some other special properties, the important one here is that it can be formed into a narrow beam, which is then swept in an arc. The gel contributes to the transfer of the sound beam into the body. It is transmitted as a series of pulses, and a detector listens for echoes. Different tissues produce different intensities of echoes, and the timing of the echo in relation to the original pulse tells the detector how far into the body it originated.