Cloud cavitation control for lithotripsy using high intensity focused ultrasound
Cloud cavitation control for lithotripsy using high intensity focused ultrasound
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DOI：
10.1016/j.ultrasmedbio.2006.05.010
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发表时间：
2006-09-01
影响因子：
2.9
通讯作者：
Matsumoto, Yoichiro
中科院分区：
文献类型：
--
作者：
Ikeda, Teiichiro;Yoshizawa, Shin;Matsumoto, Yoichiro
云空化可能是最具破坏性的空化形式。当云空化在声学上被迫塌陷时，它有可能在其中心集中一个非常高的压力，超过声压的 100 倍。我们通过实验研究了一种控制高强度聚焦超声 (HIFU) 引起的云空化破裂以破碎肾结石的方法。我们的研究检查了一种新颖的双频波，旨在控制云空化（空化控制[C-C]波形）；高频超声脉冲（1 至 4 MHz）产生云空化，高频脉冲后的低频尾随脉冲（545 kHz）迫使云塌陷。高速摄影表明，高频脉冲可以在固体表面1毫米内产生局域分布的云空化。低频超声波照射到高频引起的云空化。在阴影摄影和远程水听器测量中都观察到了随后从云空化中发出的冲击波。此外，还进行了模型和天然石材的体外侵蚀试验。就模型宝石而言，高频波和低频波组合的 C-C 波形的侵蚀率比单独使用任一波时表现出明显的优势。天然石材被侵蚀，产生的大部分碎片直径小于1毫米。结果表明，通过进一步优化超声参数和补充体内研究，云空化的控制在碎石术应用中具有未开发的潜力。
Cloud cavitation is potentially the most destructive form of cavitation. When the cloud cavitation is acoustically forced into a collapse, it has the potential to concentrate a very high pressure, more than 100 times the acoustic pressure, at its center. We experimentally investigate a method to control the collapse of high intensity focused ultrasound (HIFU)-induced cloud cavitation to fragment kidney stones. Our study examines a novel two-frequency wave designed to control the cloud cavitation (cavitation control [C-C] waveform); a high-frequency ultrasound pulse (I to 4 MHz) to create the cloud cavitation and a low-frequency trailing pulse (545 kHz) following the high-frequency pulse to force the cloud into collapse. High-speed photography has revealed that a localized distribution of the cloud cavitation can be produced within I mm on the solid surface by the high-frequency pulse. The low-frequency ultrasound was irradiated to the high-frequency-induced cloud cavitation. A subsequent shock wave emitted from the cloud cavitation was observed both in the shadowgraph photography and the remote hydrophone measurement. Furthermore, in vitro erosion tests of model and natural stones were conducted. In the case of model stones, the erosion rate of the C-C waveform showed a distinct advantage with the combined high- and low-frequency waves over either wave alone. Natural stones were eroded and most of the resulting fragments were less than I mm in diameter. The results show that the control of the cloud cavitation has untapped potential for the lithotripsy applications upon further optimization of the ultrasound parameters and complementary in vivo studies.