A dual passive cavitation detector for localized detection of lithotripsy-induced cavitation in vitro
A dual passive cavitation detector for localized detection of lithotripsy-induced cavitation in vitro
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DOI：
10.1121/1.428572
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发表时间：
2000-03-01
影响因子：
2.4
通讯作者：
Crum, LA
中科院分区：
文献类型：
--
作者：
Cleveland, RO;Sapozhnikov, OA;Crum, LA
无源空化检测器（PCD）通过感测由气泡破裂产生的声发射来识别空化事件。在这项工作中，双被动空化探测器（双PCD），由一对正交共焦接收器，用于冲击波碎石术。空化事件由两个接收器检测，并且可以通过与符合检测算法相关联的两个接收器的焦点区域的小相交体积的性质而被定位到5 mm内。一种校准技术，基于换能器的脉冲响应，被用来估计辐射压力附近的气泡崩溃。结果提出了在体外空化领域的临床和研究电液碎石机。当功率设置从12 kV增加到24 kV时，所测得的空化气泡的初级生长和崩溃的寿命从180 μ s增加到420 μ s。测得的寿命相比，以及计算的基础上的吉尔摩Akulichev制定的气泡动力学。辐射声压10毫米从崩溃的空化泡测量到从4到16 MPa的功率设置增加，虽然趋势与计算一致，预测值是四倍大于测量值。空化场的轴向长度与声场的6-dB区域相关性良好。然而，空化场的宽度（10 mm）明显窄于声场（25 mm），因为在塌陷期间气泡似乎被吸引到声轴。双PCD还检测到来自“反弹”的信号。“第二次和第三次增长和崩溃周期。测得的反弹时间不同意从单气泡模型的计算。通过将整个气泡云视为一个有效的单个气泡，可以将反弹拟合到Rayleigh塌陷模型。来自双PCD的结果与来自高速摄影的图像一致。结果表明，单气泡理论足以模拟碎石空化动力学的主要崩溃的时间，但崩溃后的气泡云动力学变得重要。(C)2000年美国声学学会。【S0001-4966（00）02503-0】。
A passive cavitation detector (PCD) identifies cavitation events by sensing acoustic emissions generated by the collapse of bubbles. In this work, a dual passive cavitation detector (dual PCD), consisting of a pair of orthogonal confocal receivers, is described for use in shock wave lithotripsy. Cavitation events are detected by both receivers and can be localized to within 5 mm by the nature of the small intersecting volume of the focal areas of the two receivers in association with a coincidence detection algorithm. A calibration technique, based on the impulse response of the transducer, was employed to estimate radiated pressures at collapse near the bubble. Results are presented for the in vitro cavitation fields of both a clinical and a research electrohydraulic lithotripter. The measured lifetime of the primary growth-and-collapse of the cavitation bubbles increased from 180 to 420 mu s as the power setting was increased from 12 to 24 kV. The measured lifetime compared well with calculations based on the Gilmore-Akulichev formulation for bubble dynamics. The radiated acoustic pressure 10 mm from the collapsing cavitation bubble was measured to vary from 4 to 16 MPa with increasing power setting; although the trends agreed with calculations, the predicted values were four times larger than measured values. The axial length of the cavitation field correlated well with the 6-dB region of the acoustic field. However, the width of the cavitation field (10 mm) was significantly narrower than the acoustic field (25 mm) as bubbles appeared to be drawn to the acoustic axis during the collapse. The dual PCD also detected signals from "rebounds." secondary and tertiary growth-and-collapse cycles. The measured rebound time did not agree with calculations from the single-bubble model. The rebounds could be fitted to a Rayleigh collapse model by considering the entire bubble cloud as an effective single bubble. The results from the dual PCD agreed well with images from high-speed photography. The results indicate that single-bubble theory is sufficient to model lithotripsy cavitation dynamics up to time of the main collapse, but that upon collapse bubble cloud dynamics becomes important. (C) 2000 Acoustical Society of America. [S0001-4966(00)02503-0].