In Local Electro Hyperthermia (LEH) the aim is to specifically destroy the tumour cells by means of a radio frequency of 13.56MHz. The system also allows any desired upward modulation of the targeted individual frequencies later. In this method of therapy, the patient is the dielectric between both the active application electrodes and is, therefore, part of a resonant oscillating circuit. Due to the capacitive thermodynamic effects in the tissue, electromagnetic current and heat are generated. With this arrangement the treatment can be customized to the patient's needs and to the location of the tumour, as well as its biology (resonance frequencies = modulation frequency).
Based on the characteristics of tumour cells mentioned in the following section the operating principles of electrical hyperthermia are as follows:
Between healthy and carcinogenic cells there are several identified and measurable differences. The primary difference between the cells is their electrical charge. The healthy cell is charged positively mainly inside and negatively outside. This charge gives rise to a certain voltage within and outside the cell.
This differential voltage leads to a variable electromagnetic field around the cells. Similarly, the ion distribution (Na, H, K, Ca, Cl) within and outside the cells varies according to their charge. That is to say, the composition of the extra-cellular fluids (ECF) differs from each other. This in turn results in the ECF reacting very differently to various external stimuli. An important characteristic is the absorption of certain frequencies. The ECF around the healthy cell mainly absorbs frequencies around 100 MHz and oscillates (resonates) simultaneously with this frequency.
On the other hand, the ECF of modified diseased cells absorbs frequencies between 10 and 15MHz. Now, if such a frequency (in the case of TCS 13.56 MHz) is transmitted into the body between the application's electrodes, it will have, as a result, a selective effect on the ECF of the tumour cells. In other words, the ECF around the tumour cell will go into oscillation at 13.56 MHz (13.56 million per second).
Local Electro Hyperthermia has been applied successfully with the following kinds of tumours: