Axisymmetric modelling of microwave ablation in biological tissue

Abstract

Microwave ablation (MWA) therapy is a hyperthermic treatment for cancerous tumors whereby\nmicrowave energy is dispersed into a target tissue region. Absorption of these waves leads to\ntemperature rise through microwave heating with the aim of exposing cancerous cells to a thermal\ndose sufficient to kill them whilst minimizing the damage to the surrounding healthy tissue. Being\nable to predict the progression of ablation during a procedure is of high value when designing\nequipment and planning patient-specific care, as current dosimetry is given in guidelines by the\nequipment provider. From a modelling standpoint this poses a complex multi-physics problem\ncoupling electro-magnetics and heat conduction. Added to this there are existence of multiple\ntemperature sensitive properties of tissue, as well as physiological processes such as blood perfusion which are heavily influential in the overall temperature profile. Here, we create a two\ndimensional axisymmetric geometry of a probe embedded within a tissue material, solving the\ncoupled electromagnetic and bioheat equation using the finite element method, utilizing hp discretisation and the NGSolve library. Temperature, electric field strength and energy absorption\ncan be calculated and investigations into the effects of the highly temperature-sensitive properties\nof tissue on the distribution of temperature throughout ablation.