Development of a transparency high molecular gel phantom for three-dimensional visualization of radio frequency electromagnetic power absorption with capsulate thermo-chromic liquid crystal

Safety of radio frequency (RF) electromagnetic fields (EMF) is commonly discussed in terms of specific absorption rate (SAR). Phantoms are useful for the dosimetry on energy absorption of RF-EMF exposures. SAR is estimated from measurements of an increase in temperature within the phantom over a short period of time following the exposure. In the past study, a method for visualizing the three-dimensional (3D) distribution of temperature due to RF-EMF energy absorption was reported. A difficulty of this method is that it can only visualize the temperature higher than the clouding point. We focused our interest on capsulate liquid crystal that has been used for visualization of temperature distribution within fluids. The objective of this study is to make a phantom containing capsulate liquid crystal so as to develop a method to visualize 3D distribution of electromagnetic power absorption. We have investigated suitable materials for the transparency phantom and discussed the method to adjust the dielectric properties of the phantom.