FINITE-ELEMENT SIMULATION OF SIGMA-60 HEATING IN THE UTAH PHANTOM - COMPUTED AND MEASURED DATA COMPARED

An initial series of comparisons are made between finite element compu tations and laboratory measurements obtained during heterogeneous phan tom heating with the Sigma 60 applicator. The phantom is a relatively complex, though still idealized, rendering of the pelvic area which ha s been used to study the deep heating characteristics of the Sigma 60 in this anatomy. Direct electric field measurements as well as inferre d SAR through transient temperature analysis are plotted against compu ted results along 11 one-dimensional tracks through the phantom. Quant itative comparisons provided through the track-by-track analysis show generally good agreement between computation and measurement. The fini te element method is found to predict well the jumps in the electric f ield when polarized perpendicularly to a muscle/fat interface. Visuali zations of the complete three-dimensional distributions are also highl ighted and correlate well with physical reasoning about the expected b ehaviour of the fields produced. Some discrepancies in the data persis t and are discussed and analysed in depth. They underscore the difficu lties that can arise in performing comparisons between measured and co mputed results and stress the need for careful and thorough investigat ions when attempting these types of model validation studies.