Abstract
A polyacrylamide phantom containing egg white has been proposed previously as an adequate tissue-mimicking material for high intensity focused ultrasound (HIFU) application. In this work, we report on measurements of egg white phantom thermal conductivity and specific heat capacity. We measured changes in acoustical properties which occurred during the heating and the coagulation process. Using a thin thermocouple embedded in the phantom material, we recorded the temperature response in the focus of the ultrasound field during HIFU application and phantom coagulation. The measured values for the thermal conductivity (0.59 ± 0.06 W/m/°C) and the specific heat capacity (4270 ± 365 J/kg/°C) are similar to the values of water. The attenuation coefficient decreased in the temperature range between 26°C and 50°C and showed a nonlinear dependence on frequency with an exponent of 1.50 ± 0.05 that was temperature-independent within the investigated temperature range. Below 65°C, no irreversible changes in material absorption were observed. The coagulation process started at 67°C and no adjacent rapid changes in temperature response were detected. In comparison with the noncoagulated phantom, the coagulated phantom material showed an enhanced absorption and a threefold higher attenuation coefficient at a frequency of 1 MHz. (E-mail: g.divkovic@dkfz-heidelberg.de)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.