Techniques for real-time monitoring and control for HIFU (High Intensity Focused Ultrasound) ablation in porcine brains in vitro studies

摘要

High Intensity Focused Ultrasound (HIFU) has been developed and clinically used as a non-invasive tumor treatment alternative. Applications of HIFU in organs such as brain and heart require higher accuracy and predictability of delivery. As evidence from other studies supports, cavitation effects (the appearance of gas/vapor bubbles) often complicate HIFU delivery by distorting and shifting the focus. Therefore, better control of cavitation effects is desirable for successful HIFU delivery. In our previous study, we had correlated the appearance of cavitation effects in ultrasonic B-model images with different HIFU parameters and compared results with the final lesions. Moreover, we had concluded that gradually developing cavitation effects ultimately contribute to the predictability of the final lesion created in terms of size and shape. We had further established a set of HIFU parameters that were suitable for tissue ablation in central nervous system tissues. In this study, to achieve better HIFU delivery by gradually controlling the growth of cavitation effects, we extended our work by adjusting HIFU power in real-time based on the observation of cavitation effects under ultrasonic imaging (hyper echoic region). The techniques were demonstrated to be effective in predicting HIFU delivery and the geometry of the final lesion.