Edge-element based finite element analysis of microwave hyperthermia treatments for superficial tumours on the chest wall.

Several three-dimensional hyperthermia treatment planning systems for deep regional hyperthermia have been successfully utilized for improving the performance of applicators such as the BSD Sigma 60. Treatment planning systems for superficial heating in contrast have been less utilized. This paper presents a study of the applicability of the finite element method that has been developed for modelling hyperthermia treatments of recurrent chest wall cancer using a patient geometry. The patient model was created by reconstructing the tissue geometry of a patient using a series of axial CT scans. Tetrahedral grids were generated from this geometry for use in finite element simulations of the SAR profile using edge-elements and in finite element simulations of the steady-state temperature profile using scalar elements. The predicted temperature profile was well correlated with thermometry readings taken after 30 min of heating during a hyperthermia treatment. The model predicted the presence of hot-spots in regions that were not monitored. Simulations also showed that the hot-spots can be manipulated by rotating the applicator by 90 degrees. This study demonstrates the ability of the model to provide detailed and accurate heating profiles in a patient specific model for superficial microwave hyperthermia of the chest wall.