Noninvasive thermometry in a reentrant resonant cavity applicator.

In order to improve the effect of hyperthermia treatment, a novel noninvasive temperature measurement method is proposed. The key mechanism of this thermometry is based on the phase change of the electrical field accompanying the temperature change inside the resonant cavity. First, the line-integrated data of this phase change distribution parallel to the electrical field are collected by rotating a cavity resonator. Then, the temperature change distribution within an object is reconstructed by the back-projection algorithm using these projection data. The proposed thermometric method may be able to monitor the temperature change distribution inside the body noninvasively without requiring a huge set-up as in the case of MRI. The basic algorithm of this method is described, and then the feasibility is indicated by the numerical analysis using the finite difference time domain (FDTD) method.