Simultaneous measurements of thermo-physical properties of egg white phantoms for HIFU by using the step-wise transient plane source technique

Abstract

Tissue mimicking egg white phantom has been developed and used in laboratory studies for the real-time visualization of high intensity focused ultrasound (HIFU) induced thermal coagulative necrosis since 2004. However, till now, very few data has been published regarding to its thermo-physical properties. In this paper, a step-wise transient plane source (TPS) method was employed to simultaneously and rapidly determine the thermal conductivity, specific heat capacity, and thermal diffusivity values of the egg white phantoms with elevated egg white concentrations (0 ∼ 40% v/v, by 10% v/v interval) at room temperature. The measured thermo-physical properties of the egg white phantoms are close to those reported values; the measured thermal conductivity (0.722 ∼ 0.759 W/(°C m)) and thermal diffusivity (1.866 × 10−7 ∼ 2.253 × 10−7 m2/s) are both linearly proportional to the egg white concentration within the investigation range, while the measured specific heat capacity (4230.5 ∼ 3271.9 J/(kg °C)) decreases in proportion to the egg white concentration. Taking account of the differences between real experiment and idea model (e.g. the limited sample size, the existence of thermal contact resistance, etc), data variations within 20% are accepted for all measurements.