Bioheat transfer in a biological tissue: a comparison among different antennas configurations

Hyperthermia treatment is nowadays recognized as the fourth additional cancer therapy technique following surgery, chemotherapy and radiation. The relevance of this cancer treatment is growing through the years, because it is part of the so called minimally or non-invasive techniques, which involve fewer complications, a shorter hospital stay, and less costs. Thermo-ablative techniques can be performed by using different forms of electromagnetic sources, in terms of radiofrequencies (Radio Frequency Ablation, RFA), microwaves (MicroWave Ablation, MWA), acoustic waves or laser energy. In this paper, the effects of thermal ablation with different antennas configurations are investigated. Single, double and triple antennas configurations are modelled in order to simulate the treatment of tumoral tissue, such as hepatic cancer, which often requires the destruction of large volume lesions. The tissue is modelled as a porous domain made up by a solid phase (tissue, interstitial space, etc.) and a fluid phase (blood). The domain is as big as to neglect boundary effects from surroundings. The heat sources are referred only to a part of this domain, and they have equal total power and energy for different antennas configurations. A Local Thermal Non-Equilibrium (LTNE) model is employed in order to consider local temperature differences between the two phases. Governing equations with the appropriate boundary conditions are solved with the finite-element code COMSOL Multiphysics®. Results are presented in terms of temperature fields and tissue damage for the three different antennas configurations and they show how using multiple antennas offers a potential solution for creating ablation zones with larger dimensions.