In recent years HIFU has been widely used for the treatment of solid tumors, such as liver tumor, bone tumor, and breast cancer.
The mechanism for therapeutic actions of HIFU includes thermal effects and non-thermal effects with the latter dominated by cavitational effects. Adjusting acoustic parameters of pulsed high intensity focused ultrasound (PHIFU) can control thermal effects and non-thermal effects; short duty cycle and high intensity favors the occurrence of cavitation. Ultrasound contrast agent (UCA) can enhance cavitational effects. Lesions caused by non-thermal effects have characteristic pathological changes quite different from those of thermal lesions.
A research article to be published on November 21, 2008 in the World Journal of Gastroenterology addresses this question. The research group led by Professor Zhi-Biao Wang from Department of Biomedical Engineering of Chongqing Medical University used PHIFU with short duty cycle and high intensity combined with UCA to damage rabbit liver VX2 tumour by non-thermal effect, and the non-thermal damage was evaluated by histopathology.