Absorbed power distributions from single or multiple waveguide applicators during microwave hyperthermia.

A theoretical model has been developed to calculate the power distributions in biological-like tissues in direct contact with waveguide applicators. A numerical solution of the coupled integral equations is performed by means of their transformation into matrix equations by using the method of moments, where the biological tissue and the applicator are described by two independent matrices. The model permits an accurate evaluation of the electric field at the aperture. The application of this method for the evaluation of arrays is also discussed. Power contour plots produced by applicators routinely used in clinics have been computed and compared with experimental results obtained with tissue-equivalent phantoms for three typical bodies: homogeneous, stratified and inhomogeneous.