Today, ultrasound scans are one of the most popular medical diagnostic methods. Ultrasound scanners are firmly established in every modern clinic, diagnostic room and even intensive care ambulance. The basic principle by which to classify ultrasound machines, is the scope of their application, and, depending on this, they are stationary and portable.

But whatever ultrasound machines, they all work on the same principle and, in general, have a similar internal structure.

The construction of ultrasound scanners
The main elements and units of the ultrasound machine are:

ultrasound transducer – the most important part of the scanner, designed for the formation and reception of sound waves;
pulse control sensor – involved in changing the strength, frequency and duration of pulses transmitted by the ultrasound transducer;
Processor unit – a computer designed to receive and process pulses from the transducers with subsequent output of human-understandable information to the monitor;
monitor – visualizes the data received from the processor unit;
keyboard, trackball (mouse) – allows entering initial data, as well as changing or adding data during or after the diagnostic session;
printer – designed for saving the obtained data on paper.

Ultrasound scanner operation is based on the properties of sound waves generated in the ultrasound sensor using the piezoelectric effect. Sensors differ in shape and size, which determine the area of visibility, as well as the operating frequency, which determines the depth of sound wave penetration (depth of scanning) and the resolution of the data obtained (picture quality). Sensor type will depend on the type of transducer, scanning method, and currently there are 4 types of ultrasound sensors: sector mechanical, linear, convex and mini-convex, phased sector.

The heart of the sensor is several quartz piezoelectric crystals which, if exposed to an electric current, begin to vibrate and emit a sound wave. When a reflected sound wave hits the crystals, they are able to produce an EMF. These unique properties of quartz crystals have led to the creation of ultrasound scanners and a whole new field of medical diagnostics. To filter the sound waves hitting the sensor, it is equipped with a special filtering layer, and an acoustic lens allows you to tune in to receive the desired wave.

How it works
The principle of operation of any ultrasound machine is as follows. The sensor emits sound waves of varying frequency (from 1 to 18 MHz), amplitude and duration. Part of the waves, penetrating into the body and reaching the boundaries of media (e.g., liquid – soft tissue or soft tissue – bone), penetrate further, and part – is reflected and recorded by the sensor. Based on the known speed of sound propagation in certain media of the body, the processor unit calculates the time of sound wave passage from the sensor to the scanned organ, which as a result allows you to make a general picture of the diagnosis and draw conclusions.