Thermal Simulation of Cavitation-Enhanced Ultrasonic Heating Verified with Tissue-Mimicking Gel

High-intensity focused ultrasound (HIFU) causes selective tissue necrosis through heating and is used as a noninvasive treatment in cancer therapy. However, there is a problem that it takes several hours to treat a large tumor. To shorten the treatment time, there is need for the development of a highly efficient method. It is known that cavitation bubbles generated by HIFU enhance the heating effect of ultrasound. In this study, the enhancement of the heating effect due to cavitation was considered in the bio-heat transfer equation (BHTE) by increasing the absorption coefficient in the region of generated cavitation. The absorption coefficient was calculated by curve fitting between the temperature rise at the focal point in the experiment and that in the simulation. The results show that the increased absorption can simulate the enhancement of the temperature rise by cavitation bubbles. (C) 2012 The Japan Society of Applied Physics