SAR PATTERNS FROM AN INTERSTITIAL MICROWAVE ANTENNA-ARRAY HYPERTHERMIA SYSTEM.

Theoretical and measured values of the SAR (specific absorption rate) distribution are compared for an array of four 915-MHz antennas implanted on the corners of a 2-cm square array. The overall length of the antennas was assumed to be 7 cm in the theoretical calculations and was either 6 or 7 cm for the measurements. In general, there was good agreement between the theoretical predictions and the experimental results. Both theory and experiment demonstrated that the maximum SAR occurred in the junction plane of the antenna array and at the center of the square array. The experiments showed that the SAR patterns were reproducible, and that the use of double stub tuners to minimize the reflected power for each antenna resulted in poorer SAR patterns due to phase variations created by the tuners. However, the use of an attenuator with each antenna to equalize the maximum SAR from each antenna did improve the SAR distributions slightly.

Duke Scholars

Author Terence Z. Wong Radiology, Nuclear Medicine