The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
Ultrason Sonochem. 2013 Nov;20(6):1370-5. doi: 10.1016/j.ultsonch.2013.03.002. Epub 2013 Mar 26.
The aim of this study is to investigate the mechanism of the erosion process induced by 1.2 MHz pulsed high-intensity focused ultrasound (pulsed HIFU). By using Sonochemiluminescence (SCL) photograph, the initiation and maintenance of active cavitation were observed. In order to understand the role of both inertial cavitation and stable cavitation, a passive cavitation detection (PCD) transducer was used. Since the exposure variables of HIFU are important in the controlled ultrasound tissue erosion, the influence of pulse length (PL) and duty cycle (DC, Ton:Toff) has been examined. The results of tissue hole, SCL observation and acoustic detection revealed that the erosion was highly efficient for shorter PL. For higher DCs, the area of SCL increased with increasing PL. For lower DCs, the area of SCL increased with increasing PL from 10 to 20 μs and then kept constant. For all PLs, the intensity of SCL decreased with lower DC. For all DCs, the intensity of SCL per unit area (the ratio of SCL intensity to SCL area) also decreased with increasing PL from 10 to 80 μs, which suggested that the higher the intensity of SCL is, the higher the efficiency of tissue erosion is. At DC of 1:10, the position of the maximum pixel in SCL pictures was distant from the tissue-fluid interface with the increasing PL because of shielding effect. By the comparison of inertial cavitation dose (ICD) and the stable cavitation dose (SCD), the mechanisms associated with inertial cavitation are very likely to be the key factor of the erosion process.
本研究旨在探究 1.2MHz 脉冲高强度聚焦超声（pulsed HIFU）诱导侵蚀的机制。通过使用声致发光（SCL）摄影，观察了活性空化的引发和维持。为了了解惯性空化和稳定空化的作用，使用了被动空化检测（PCD）换能器。由于 HIFU 的暴露变量在超声组织侵蚀的控制中非常重要，因此研究了脉冲长度（PL）和占空比（DC，Ton:Toff）的影响。组织孔、SCL 观察和声学检测的结果表明，较短的 PL 使侵蚀效率更高。对于更高的 DCs，随着 PL 的增加，SCL 的面积增加。对于较低的 DCs，随着 PL 从 10 到 20μs 的增加，SCL 的面积增加，然后保持恒定。对于所有 PL，随着 DC 的降低，SCL 的强度降低。对于所有 DC，单位面积上的 SCL 强度（SCL 强度与 SCL 面积的比值）也随着从 10 到 80μs 的 PL 增加而降低，这表明 SCL 强度越高，组织侵蚀效率越高。在 DC 为 1:10 时，随着 PL 的增加，SCL 图像中最大像素的位置远离组织-流体界面，因为屏蔽效应。通过比较惯性空化剂量（ICD）和稳定空化剂量（SCD），与惯性空化相关的机制很可能是侵蚀过程的关键因素。
