Three-dimensional Measurement of Electromagnetic Power Absorption in a Phantom with Thermo-chromic Liquid Crystal

Abstract

A new method to measure three-dimensional (3D) temperature distributions is developed. This method is applicable to the experimental studies to relate tissue temperature elevation with specific absorption rate (SAR) in a material exposed to radiofrequency electromagnetic fields (RF-EMF). The temperature sensor used in this study is micro-capsulated thermo-chromic liquid crystal (MTLC). A gel phantom containing MTLC is made from carrageenan. An exposure experiment is performed by using a dipole antenna. Temperature distributions are visualized as color distributions in real-time and non-destructive way. Calibration curve is obtained so as to relate the hue of the color to the temperature. Temperature distributions of the exposure experiment are estimated using the curve. The exposure experiments with other RF-EMF sources are also performed. These results show that this method has wide application for measuring 3D temperature distributions.