Jun 05, 2018
The method of ultrasound treatment of was developed in the Soviet Union in the 1960s-1970s. In the same years, multifaceted clinical studies were conducted to study the effect of ultrasonic waves on various processes occurring in the human body.
In physiotherapy, high-frequency ultrasound was applied within frequencies from 800 kHz to 3 MHz with wavelengths of about 1.5 μm. Ultrasound, in contrast to conventional, audible sound, spreading in all directions spherically, spreads at certain frequencies rectilinearly in the form of directed narrow beams, which ultimately makes it possible to localize the pathological foci in the patient's body.
The above studies have established that: •
• an ultrasound having a frequency of 800 to 900 kHz penetrates the body tissues to a depth of 4 to 15 cm, while absorbing the energy of ultrasonic waves by layered tissue structures under the skin is accompanied by the release of heat. In addition, part of the energy of ultrasonic waves passes into the energy of chemical bonds that arise when they affect pathological foci in the patient's body;
• at the depth of the sciatic nerve in the hypogynous fold( it is from 1.5 to 2 cm), a zone of semi-absorption of ultrasound with a subsequent energy loss of 2 times was detected;
• from bones reflected to 40-60% of the energy of the ultrasonic wave, with the formation of transverse reflected waves, which to some extent complicate the structure of the ultrasound field and analysis of the biological processes developing in the pathological focus of the body;
• in the soft tissues of the body, the propagation velocity of the ultrasonic wave is from 1,400 to 1,500 m / s, which is almost the same as in any medium;
• When ultrasound is dosed on pathological foci in the body, the power of the ultrasound beam, which is measured in watts per second, is of great importance. In physiotherapy, the ultrasound intensity is estimated from the energy density, which is understood to be 1 W / s, referred to 1 cm2 of the ultrasonic wave flow area. It is expressed in watts per square centimeter. In medical practice, pulsed ultrasound is used, when pulses of ultrasonic oscillations alternate with pauses, with the appearance of cavitation
with the appearance of discontinuities in the continuity of the medium, as well as the appearance of voids, followed by their "slamming".Eventually, substances with a sharp oxidative and reducing action, acceleration of diffusion and restructuring of molecular structures are formed in the body. But when pulsed high-frequency ultrasound is used to influence pathological foci, the phenomena of cavitation sharply weaken and disappear. In the course of clinical studies it was found that with moderate and low ultrasound intensity in living tissues due to their high viscosity, cavitation phenomena are practically not expressed, but only pulsations of natural vesicles in biological fluids and intensification of intracellular and extracellular microflows of fluid( biological), ceasingwhen the ultrasound generating apparatus is turned off. Thus, ultrasound has a very effective effect on the human body. In particular, reflex and humoral reactions develop, on which the use of ultrasound in therapy is based to a certain extent.