The ultrasound is a wave sound whose frequency exceeds the limit detectable by the human ear (ie, the sound can not be perceived by people as it is located around the spectrum of 20,000 Hz).
There are multiple applications of ultrasound. At an industrial level, it allows measuring distances or developing non-destructive tests, for example. Another very frequent use takes place in the field of medicine.
The ultrasound is one of the most popular procedures related to the ultrasound. The emission of this type of sounds directed towards a body allows to form an image that is used for diagnostic purposes. A device known as a transducer beams the ultrasound waves toward the mass under study and then receives its echo. A computer is responsible for converting this echo into an image that is displayed on a screen.
Thanks to the fact that it does not use any type of radiation, ultrasound is used to visualize the fetus that is forming in the womb. Placing a gel on the skin helps the correct transmission of ultrasound.
Ultrasound is also useful as an insect repellent. Some computers or mobile phones are capable of reproducing an acoustic wave that annoys insects and keeps them away.
Species like bats and dolphins use ultrasound as a kind of radar. The phenomenon, known as echolocation, takes place when the sound waves emitted by these animals "bounce" off objects around them and create a kind of "image" .
When a liquid is subjected to ultrasound, certain cavities are generated that, once they collapse, reach temperatures of 30 thousand degrees Celsius and the phenomenon called sonoluminescence takes place, during which the emission of light occurs. Some research attempts to show that cold fusion can take place in these cavities, a nuclear fusion reaction that occurs at temperatures well below those necessary to produce a thermonuclear reaction.
Regarding its work in the body, it uses equipment capable of transferring mechanical waves of a frequency higher than sound through a gel, which allows it to propagate and transmit energy (heat) due to the vibrations produced by the waves.
The vibrations cause the cells to move, improving healing and, at the same time, increasing the temperature of the region where the ultrasound is applied. However, as noted above, patients do not perceive this thermal change; The reason is that there are very few heat receptors deep within the tissues.
Regarding the criteria for the application of ultrasound in physiotherapeutic treatments, the time, the dimensions of the surface to be treated and those of the head are counted (the first of these parameters depends on the remaining two). In general, applications are made that last between 2 and 6 minutes and only during the first sessions, since their main objective is to reduce inflammation, which does not usually last more than 5 days, and contribute to fibroplasia (generation of fibrous tissue during healing), which does not exceed 3 weeks.
Depending on the healing time of each patient, among other personal factors, the number of ultrasound sessions varies. On average, however, it is estimated that its use does not exceed 8 applications, over 3 weeks.