Radio Frequency Waves
They are a form of electromagnetic energy and can be represented as waves of oscillating electric fields. This is a non-ionizing radiation that doesn’t produce changes in the molecular structure of substances, water being responsible for the transformation into heat of the high frequency energy.
The mechanisms of interaction of microwaves with matter are ionic conduction and dipole rotation. This dipolar rotation is caused when the electrical dipole, formed by molecules of oxygen (negative) and hydrogen (positive), is subjected to an external electric field creating a torque on each molecule and forcing it to rotate.
Dipole rotation decreases with increasing temperature, while the ionic conduction increases with temperature. This means that first RF energy causes higher turnover and as the temperature rises, the rotation begins to decrease and increase the ionic conduction.
The main characteristic of this type of electromagnetic waves treatment is depth, since it goes through the skin and fatty tissue especially without losing energy, giving all his energy into the underlying muscle layers. The biological effects of the microwaves depend primarily on the structure of the tissues that pass through, i.e., their electrical properties (electrical constant, specific resistance), of its water content, as well as those events with reflections between tissues of different properties.
The tissues of the human body must maintain an average temperature of 37 ° C, so if an increase in temperature is caused, the neurovegetative system will detect it and provoke the thermoregulation mechanisms, being the most immediate the vasodilation, so that blood flow increases, bringing warm blood to areas of lower thermal gradient. If this mechanism is not sufficient to maintain body temperature at 37 ° C, the nervous system will induce sweating to cool the skin by evaporation, maintaining the vasodilation. If the thermoregulation is not achieved, a vasoconstriction can be produced, which is accompanied by a contraction of the smooth muscle of the sweat glands.
Therefore, the therapeutic effect of diathermy is based on two fundamental aspects:
The vasodilatation that facilitates the movement of the agents of inflammation and the contribution of repair agents.
The effect that stimulates the formation of new tissues.