V.N. Makarov¹, N.A. Boos²

1–2 MIREA — Russian Technological University (Moscow, Russia)

In the field of oncology therapy in the last few decades, methods of local thermal destruction have been intensively developed, which is heating a malignant neoplasm to a coagulation temperature and above. Among them, the most common are radiofrequency ablation (RFA) and microwave ablation (MWA). The time of destruction of tumors with these methods does not exceed 10-15 minutes, and the procedure itself can be performed on an outpatient basis without hospitalization of the patient. The main problem of existing installations of microwave and radiofrequency thermal destruction is the insufficient amount of tissue coagulation. Depending on the type of tissue, various methods of exposure to an electromagnetic field can be used. Thus, in the RF range, ohmic heating can be used, suitable for tissues with a high degree of conductivity, while for tissues with low conductivity, dielectric heating can be used. To increase the heating volume, it is proposed to combine ohmic and dielectric heating. The purpose of this work was computer simulation of a combined heating process. A computer simulation of the combined heating electrode was carried out. The COMSOL Multiphysics software package was used to create the model. The algorithm for constructing the model consisted of creating geometry, selecting the dimensions of the electrode working areas, setting power parameters, and applying a finite element mesh. The model was two-dimensional. Various configurations of the combined heating electrode were considered. As a result, it was found that it is possible to create a heating area with a larger volume than in the case of separate heating. The general shape of the resulting heating in all cases had an elliptical shape. At the same time, the heating pattern for RF working areas with a size of 5 mm had a shape more suitable for the treatment of spherical tumors than for working areas with a size of 10 - 20 mm. The obtained results demonstrate the possibility of increasing the heating volume by more than 40% in comparison with single operating modes. The most suitable sizes for RF heating zones were calculated, at which the heating volume will be maximum. The use of combined heating in clinical practice will partially solve the problems of insufficient heating volume, which are inherent in the single-electrode heating mode in both RFA and MWA.

Makarov V.N., Boos N.A. Combination of ohmic and dielectric heating for tumor ablation. Electromagnetic waves and electronic systems. 2022. V. 27. № 6. P. 38−44. DOI: https://doi.org/10.18127/j15604128-202206-05 (in Russian)

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