An ultrasound scanner is a medical device that provides images of most soft tissues by using ultrasonic waves. This means that diagnostic images can be obtained from the echoes obtained by the emission of ultrasound waves. These waves are produced by an instrument called a transducer, which in addition to generating the ultrasound waves is also able to detect the echoes reflected by the ultrasound, generating two-dimensional images of tissues and organs.
Ultrasounds are high-frequency sound waves (more than 20,000 cycles per second or 20 kHz) not audible to humans. Different tissues alter waves in different ways, some reflect them directly, and some disperse them as echoes before they reach the transducer. That is, using the speed of sound and the time each echo returns, the scanner calculates the distance between the transducer and the tissue boundary. Deeper reflected echoes are dimmer than surface echoes. When the echoes return to the transducer, it is possible to reconstruct a two-dimensional map of tissues and organs.