Comparison of two-dimensional numerical approximation and measurement of SAR in a muscle equivalent phantom exposed to a 915 MHz slab-loaded waveguide

Abstract

Computer predictions of the specific absorption rate (SAR) distribution in a uniform muscle-equivalent phantom with an overlying bolus have been compared to those measured experimentally. The microwave source was a 10 10×cm cm slab-loaded waveguide applicator operating at 915 MHz. The modelling technique (theory) combines the equivalence principle and a two-dimensional finite element technique to determine the incident and the scattered electric fields separately. The E-field was measured using a small dipole device oriented parallel to the polarized field of the waveguide source. Comparisons of the predicted and measured SAR were made for various bolus properties, and reasonable agreement with theory was found in each case. The results demonstrate the usefulness of numerical modelling in characterizing the fields from microwave applicators used in clinical hyperthermia.

Key Words:

• Numerical modelling
• finite elements
• waveguide applicator
• electric field
• phantom studies