A technology of absolute interest and very widespread, ranging from medical diagnostics to pain therapy, from aesthetic treatments to rehabilitation.
Ultrasonic waves are acoustic waves with frequencies not audible to the human ear, greater than 20,000 vibrations per second. The technique consists in providing different areas of the body with special applicators equipped with ultrasonic transducers.
It is a particularly useful technology because, depending on the frequency of emission, it allows us to work on the surface or more deeply.
For example, you can use a spatula with 25-30 KHz frequencies to work on the epidermis, for facial cleansing, exfoliation and tissue oxygenation.
With emission frequencies of 3MHz there is the possibility of letting energy penetrate in the order of 1-2 mm and at 1 MHz to go even deeper.
In this case the ultrasonic waves act at the level of the dermis creating heat and stimulating the fibroblasts for the production of collagen and elastin; therefore they have a deep tissue firming action.
The vast field of application is due to the numerous and important biological effects that ultrasounds, passing through the tissues, determine: thermal, mechanical and chemical effects.
Ultrasounds produce heat through vibrations, impact and friction of cellular and intercellular structures that make up tissues, crossed by sound waves.
Heating affects the deep structures and is established quickly; however, a thermal balance is soon established due to the rapid dispersion of heat due to the blood flow.
The thermal elevation generates, as secondary effects, increased cellular metabolism and vasodilation.
The passage of the sound wave in the tissues determines the oscillation of the particles, which compose it; the oscillations have the same acceleration and speed as the ultrasonic beam. Although the displacement suffered by the individual particles is small, the pressure variations it produces are considerable and such as to generate important mechanical effects in the tissues.
The mechanical modifications induced by ultrasound determine:
- Acceleration of diffusion processes across cell membranes.
- Cleavage of complex molecules (proteins, polysaccharides, etc.).
- Tissue micromassage.
Chemical – Cavitation
The cavitation process consists of the formation of gaseous bubbles (cavities) in liquids crossed by ultrasonic waves, which then implode.
This phenomenon occurs when the liquid is subjected to considerable depression, when the absolute pressure becomes lower than the liquid tension, a force field is determined with the transformation of the gases contained in the liquid into gaseous bubbles.
Ultrasound as a cure
The therapeutic effects of ultrasounds are partly due to the increase in temperature. They are represented by analgesia, muscle relaxation and the fibrolytic and trophic effect.
The analgesic effect is due to the action of heat and probably also to a direct action of the ultrasounds on the sensitive nerve endings.
The relaxation of contracted muscles is linked to the thermal effect and the action of tissue micromassage induced by ultrasound.
The fibrolytic effect is due to the oscillations of the tissue particles produced by the ultrasounds, which determine the breakdown of the collagen fibers of fibrous tissues.
The vasodilation, which follows the thermal elevation, facilitates the removal of the catabolites and sends nutrients and oxygen into the tissues; in this way the ultrasounds improve the trophism of the tissues, facilitate the repair of tissue damage and accelerate the resolution of inflammatory processes.