V.N. Makarov1, N.A. Boos2

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

1 Firm "TECHNOSVET" LLC (Moscow, Russia)

Today, various alternative methods of cancer therapy are widely used. These methods include radiofrequency ablation (RFA), the essence of which is the introduction of one or more needle electrodes into the tumor, followed by heating the area due to the passage of high-frequency current through biological tissues. The method has proven itself in the treatment of spherical tumors, however, the created heating area is not suitable for effective treatment of flat tumors. To solve this problem, it is necessary to create an electrode heating system with a special design. It is proposed to take as a basis a standard monopolar circuit, in which a flat electrode will be used instead of a passive electrode, which acts as an additional source of heating. The aim of this work was computer simulation of an electrode system of radiofrequency heating for the treatment of flat tumors. The simulation was carried out in the COMSOL Multiphysics software environment. Systems with 5 and 9 needle electrodes were considered. The diameter of the holes through which the needle electrodes were inserted was 10 mm, the diameter of the needle electrodes was 1.6 mm, and the diameter of the flat electrode was 60 mm. Heating time 10 minutes, power – 50 watts. The human liver was considered as the heating medium. Various designs were calculated, the most suitable was the design combining the classical approach to heating with the NO-TOUCH method. The proposed system is the most suitable for the treatment of flat tumors, the resulting heating is uniform, with a clear ablastic zone. The system does not fully implement the NO-TOUCH technique, but the risk of seeding tumor cells remains minimal due to the fact that only one needle electrode directly touches the tumor tissue. A computer simulation of an electrode system of radiofrequency heating for the treatment of flat tumors was carried out. In the course of the work, several potentially suitable designs were considered and one design was selected that best meets all the requirements necessary for tumor therapy. If this electrode system is introduced into real clinical practice, the process of treating flat tumors will be simplified, while the effectiveness of treatment will increase due to an increase in the input power.

Makarov V.N., Boos N.A. Comparison of characteristics of various radiofrequency heating systems. Biomedicine Radioengineering. 2022. V. 25. № 6. Р. 46-51. DOI: https://doi.org/10.18127/j15604136-202206-05 (In Russian)

1. Sostoyaniye onkologicheskoy pomoshchi naseleniyu Rossii v 2021 godu. Pod red. A.D. Kaprina. V.V. Starinskogo. A.O. Shakhzadovoy. MNIOI im. P.A. Gertsena. filial FGBU «NMITs radiologii» Minzdrava Rossii. M.: 2019. 239 s. (in Russian).
2. Makarov V.N., Makhov M.A., Miroshnik V.I., Shmeleva D.V., Kuchin K.O. Teplovizionnoye issledovaniye temperaturnogo polya pri bipolyarnoy mnogoelektrodnoy ablyatsii. Biomeditsinskaya radioelektronika. 2019. № 2. S. 5–14. (in Russian).
3. Reshetov I.V., Makarov V.N. Radiochastotnaya ablyatsiya opukholey golovy i shei bez kontakta s elektrodami. Head & neck. Russian journal. 2018. V. 6(3). P. 20–27. (in Russian).
4. Makarov V.N. Primeneniye raspredelennogo nagreva dlya teplovogo razrusheniya opukholey (kratkiy obzor). Biomeditsinskaya radioelektronika. 2018. № 1. S. 54–60. (in Russian).
5. Makarov V.N., Boos N.A. Sravneniye protsessov radiochastotnoy ablyatsii dlya monopolyarnykh i bipolyarnykh sistem. Biomeditsinskaya radioelektronika. 2021. T. 24. № 3. S. 57–63. (in Russian).
6. Makarov V.N., Boos N.A. Tendentsii razvitiya ustanovok dlya radiochastotnoy ablyatsii. Biomeditsinskaya radioelektronika. 2021. T. 24. № 6. S. 58–68. (in Russian).
7. Hocquelet A., Aubé C., Rode A., et al. Comparison of no-touch multi-bipolar vs. monopolar radiofrequency ablation for small HCC. J. Hepatol. 2017. V. 66. P. 67–74.
8. Chang W., Lee J.M., Lee S.M., et al. No-Touch Radiofrequency Ablation: A Comparison of Switching Bipolar and Switching Monopolar Ablation in Ex Vivo Bovine Liver. Korean J. Radiol. 2017. V. 18(2). P. 279–288.
9. Seror O., N’Kontchou G., Van Nhieu J.T., et al. Histopathologic comparison of monopolar versus no-touch multipolar radiofrequency ablation to treat hepatocellular carcinoma within Milan criteria. J. Vasc. Interv. Radiol. 2014. V. 25. P. 599–607.
10. Seror O., N’Kontchou G., Nault J.C., et al. Hepatocellular carcinoma within Milan criteria: no-touch multibipolar radiofrequency ablation for treatment-long-term results. Radiology. 2016. V. 280. P. 611–621.
11. Wu L.W., Chen C.Y., Liu C.J., et al. Multipolar radiofrequency ablation with non-touch technique for hepatocellular carcinoma ≤ 3 cm: a preliminary report. Adv. Dig. Med. 2014. V. 1. P. 80–85.