Numerical model of microwave ablation of the myocardium

A heart-torso model based on the finite element method (FEM) is used to predict the behavior of an axisymmetric well coupled loaded monopole for use in cardiac hyperthermia. Both the electromagnetic and the thermal problems are solved for the axisymmetric geometry. In order to determine the effect of antenna design and frequency on the temperature distribution, lesions were simulated with 915 and 2450 MHz loaded monopoles. The heating patterns from the microwave antenna were compared to that induced by a similar active electrode at 500 kHz (RF energy). Heating patterns induced by RF energy drop off more abruptly both radially and axially than MW energy, resulting in a lesion depth twice the size for the MW antenna.