Changes in the dielectric properties of rat prostate ex vivo at 915 MHz during heating.

Changes in the tissue dielectric properties at 915 MHz of rat prostate tissue due to heating at temperatures in the range 45-75 degrees C were measured. The changes were found to be reversible with temperature and independent of the time of heating. The dielectric properties at 23 +/- 1 degrees C were measured as epsilon' = 62.8 +/- 2.7 and sigma = 1.17 +/- 0.07 S/m, while the linear temperature coefficients for reversible changes were 1.10 +/- 0.11%/ degree C for conductivity and -0.31 +/- 0.05% /degree C for relative permittivity. These properties and their temperature coefficients can be utilized in microwave treatment planning programmes to provide insight into the effects of dielectric changes that arise during microwave thermal therapy of prostate cancer.