In high-intensity focused ultrasound (HIFU) treatment, a method that monitors tissue changes while irradiating therapeutic ultrasound is needed to detect changes in the order of milliseconds due to thermal coagulation and the presence of cavitation bubbles. The new filtering method in which only the HIFU noise was reduced while the tissue signals remained intact was proposed in the conventional HIFU exposure in our preliminary study. However, HIFU was irradiated perpendicular to the direction of the imaging ultrasound in the preliminary experiment, which was believed to be impractical. This study investigated the efficacy of the proposed method a parallel setup, in which both HIFU and imaging beams have the same axis just as in a practical application. In addition, this filtering algorithm was applied to the “Trigger HIFU” sequence in which ultrasound-induced cavitation bubbles were generated in the HIFU focal region to enhance heating. In this setup and sequence, HIFU noise level was increased and the summation or difference tone induced by the interaction of HIFU waves with the imaging pulse has the potential to affect this proposed method. Ex-vivo experiments proved that the HIFU noise was selectively eliminated by the proposed filtering method in which chaotic acoustic signals were emitted by the cavitation bubbles at the HIFU focus. These results suggest that the proposed method was practically efficient for monitoring tissue changes in HIFU-induced cavitation bubbles.

在高强度聚焦超声（HIFU）治疗中，需要一种在照射治疗性超声的同时监视组织变化的方法，以检测由于热凝结和空化气泡而导致的毫秒级变化。在我们的初步研究中，提出了一种新的滤波方法，其中仅降低了HIFU噪声，而组织信号仍保持完整。然而，在初步实验中，垂直于成像超声的方向照射HIFU，这被认为是不切实际的。这项研究调查了所提出方法并行设置的功效，其中HIFU和成像光束都与实际应用中的轴相同。此外，将该过滤算法应用于“触发HIFU”序列，在该序列中，在HIFU焦点区域中产生了超声诱导的空化气泡，以增强加热。在这种设置和顺序中，HIFU噪声水平增加了，并且HIFU波与成像脉冲的相互作用所引起的求和或差异音可能会影响该方法。体外实验证明，通过提出的滤波方法有选择地消除了HIFU噪声，在该滤波方法中，HIFU焦点处的空化气泡发出了混沌声信号。这些结果表明，所提出的方法对于监测HIFU诱导的空化气泡中的组织变化实际上是有效的。HIFU噪声水平增加，并且HIFU波与成像脉冲的相互作用引起的求和或差异音可能会影响此方法。体外实验证明，通过提出的滤波方法有选择地消除了HIFU噪声，在该滤波方法中，HIFU焦点处的空化气泡发出了混沌声信号。这些结果表明，所提出的方法对于监测HIFU诱导的空化气泡中的组织变化实际上是有效的。HIFU噪声水平增加，并且HIFU波与成像脉冲的相互作用引起的求和或差异音可能会影响此方法。体外实验证明，通过提出的滤波方法有选择地消除了HIFU噪声，在该滤波方法中，HIFU焦点处的空化气泡发出了混沌声信号。这些结果表明，所提出的方法对于监测HIFU诱导的空化气泡中的组织变化实际上是有效的。体外实验证明，通过提出的滤波方法有选择地消除了HIFU噪声，在该滤波方法中，HIFU焦点处的空化气泡发出了混沌声信号。这些结果表明，所提出的方法对于监测HIFU诱导的空化气泡中的组织变化实际上是有效的。体外实验证明，通过提出的滤波方法有选择地消除了HIFU噪声，在该滤波方法中，HIFU焦点处的空化气泡发出了混沌声信号。这些结果表明，所提出的方法对于监测HIFU诱导的空化气泡中的组织变化实际上是有效的。