V.V. Komarov, I.I. Novruzov

Such minimally invasive therapy as microwave ablation is an attractive alternative to the existing surgery proce-dures of tumor treatment. Along with contact-type waveguide applicators and reentrant cavity resonators numer-ous interstitial microwave antennas are widely utilized nowadays in medicine practice. Ablation therapy is based on local heating of tumor up to temperatures 50÷90ºC by means of coaxial radiator inserted into the human body. Most of such devices are designed in the form of dipole antenna which generates high power density domain around applicator. Tow modifications of monopole type coaxial antenna design with cone shaped dielectric or metal tip are consi-dered in present study. Coupled electromagnetic bioheat conduction mathematical model is formulated for simulation microwave heating processes in tumor. Given coupled problem is solved using 2D axial-symmetrical finite element method. The same 2D model is employed also for optimization of return loss in interstitial applicator under study. One more 3D numerical algorithm on finite difference time domain method is used for verification of simulation data. Both approaches have demonstrated good agreement near operating frequency 2.45 GHz. Obtained results show that distributions of temperature fields in the interaction zone depend on material of antenna tip. This peculiarity can be used for treatment of various sized and shaped tumors.