Does the human body have a frequency

Physical principle

Radio waves are used to overheat the body. There are various types of conductive tissues with many ions in the human body. Water molecules in the tissue have an electrical dipole moment, which in the electromagnetic alternating fields of radio waves leads to oscillations of the water molecules or to acceleration of the ions. Therefore, water-containing tissue can be heated by coupling in radio frequency radiation.

The conductivity of the types of tissue depends on the frequency used. Therefore, different frequencies have different depths of penetration in the body. High frequencies are absorbed very strongly in the body, but they do not penetrate very deeply. Low frequencies have a high penetration depth, but cannot focus on the tumor due to their long wavelength in the human body. Reflections can occur at the interfaces of the different types of tissue with their different conductance values. This creates undesirable overheating, so-called "hot spots", which can lead to burns.

In principle, the radio waves can be applied in different ways: In the method we use, the tumor is irradiated from the outside using an antenna system (radiative method). The coupling of the electromagnetic waves takes place via a water cushion, called a water bolus, which contains non-conductive water. On the one hand, this prevents the energy in the bolus from being converted; on the other hand, the water can be used to cool the surface of the skin.

The radiative hyperthermia system we use uses frequencies between 70 and 220 MHz with a wavelength of 5 to 30 cm. The wavelength is decisive for the focusability of the radio waves in the body.

The antenna system, which is housed in the so-called applicator, is placed in the middle of the target area. By controlling the frequency and the phases of the radiated electromagnetic waves and their amplitudes, the focus and depth of penetration can be determined.