Thermal model for the local microwave hyperthermia treatment of benign prostatic hyperplasia.

A system for the noninvasive localized, hyperthermia treatment of benign prostatic hyperplasia was investigated. The system uses a microwave transrectal antenna with a water cooled jacket to achieve localized hyperthermia. The purpose of this study is to model the temperature rise in the prostate and in the surrounding tissue during treatment. The SAR distribution for the transrectal probe is measured in a muscle tissue equivalent phantom. The SAR information is used with a finite element solution of the bioheat transfer equation to give the temperature rise during the treatment. Also the finite element solution is further used to determine the effect of the microwave power, the cooling fluid temperature and the blood perfusion on the tissue temperature rise. The results of the solution are compared to temperature measurements in a canine protocol. It was found that the maximum temperature rise in the tissue during treatment is 44 degrees C at a depth of 2 cm from the rectal mucosa.