What is the relation between RF signal and ultrasound scanning

[emerson_11]

I have come across many papers which says that raw RF signal is taken from the ultrasound device (eg. The RF signal is the
scattered signal received by the ultrasound scanner’s probe). So upto my knowledge US scanning works on sound waves but what does it means RF data. Where does it comes from?

[betwixt]

According to "Electronic Journal «Technical Acoustics»" 2007:

The RF signal is the scattered signal received by the ultrasound scanner’s probe. It thus contains all the
information on the propagation of the acoustic waves and their interactions with the scanned medium.

So I would assume the RF reference is the recovered electrical signal from the microphone rather than the compression waves from the ultrasonic reflection. It would comprise almost entirely the same frequency as the emitted ultrasound rather than frequencies used in radio communication.

Oddly, almost all internet references are to emitting RF in cosmetic applications, most of which look decidedly ineffective and possibly dangerous.

Brian.