PHYSICAL ASPECTS OF CAVITATION IN EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY

尽管SWL已经在临床上使用了15年以上， 石头交流的物理机制仍然不是很好。 明白了。然而，现在有越来越多的实验证据 以及临床社区逐渐接受的SWL 会对治疗后的肾脏造成某种程度的永久性损害。这个 造成这种组织损伤的机制也不是很好。 明白了。我们假设声空化是主要因素。 结石粉碎和肾脏损伤。一个相互竞争的机制是 SWL冲击波在组织中产生的剪应力。声空化 空化气泡的生长和猛烈崩塌的结果 由SWL产生的声波波形。我们已经开发了一套 先进的实验工具，使我们能够探测到空化 环境范围广泛，具有一定程度的时空 决议。使用这些工具，我们已经获得了大量的 证据表明，SWL在两个区域都产生了空化 人体肾脏的实质和收集系统。我们还有 发现了一种改装电液碎石机的方法 产生具有类似冲击波幅度、脉冲长度、 和声能与传统的SWL波形相同，但不 产生空化。此外，我们还找到了一种方法来增强 暴力空化坍塌，以及将空化限制在 高度本地化的卷。我们计划利用这些不同的发现和 确定空化和剪切的相对作用的工具 在石头粉碎和组织损伤方面。我们还取得了相当大的进展 在开发一套理论模型方面取得进展，该模型将 允许我们在任何位置和时间计算SWL波形 体外或体内。此外，给出一个具体的波形，我们就可以计算 空化场对该波形的响应，并确定， 尽管是以一种粗略的方式，但在各种情况下，空化破坏的可能性 在体外和体内环境中。我们建议通过以下方式来检验我们的假设 进行了一系列实验，在这些实验中，我们将把SWL应用于各种 在体外和活体模型中，我们将使用我们的空化 用于确定该病毒的存在和位置的检测技术 空化；稍后，我们将把组织损伤与 气穴的存在或不存在。我们还将开展一系列的 与石块粉碎有关的类似实验。利用这些结果，我们 应该使用我们的理论模型来设计一种能够优化 石块粉碎，最大限度地减少组织损伤。

Despite the fact that SWL has been in clinical use for over fifteen years, the physical mechanisms for stone communication are still not well understood. However, there is now a growing body of experimental evidence and an evolving general acceptance by the clinical community, that SWL leads to some degree of permanent damage to treated kidneys. The mechanisms responsible for this tissue damage are also not well understood. We hypothesize that acoustic cavitation is a dominant factor in both stone comminution and kidney damage. A competing mechanism is the shear stress produced in tissue by the SWL shock wave. Acoustic cavitation results from the growth and violent collapse of cavitation bubbles produced by the SWL acoustic waveform. We have developed a set of sophisticated experimental tools that permit us to detect cavitation in a broad range of environments and with some degree of spatial and temporal resolution. Using these tools, we have acquired a significant body of evidence that demonstrates that SWL generates cavitation in both the parenchyma and the collecting system of the human kidney. We have also discovered a method of modifying an electrohydraulic lithotripter to produce a waveform that has a similar shock wave amplitude, pulse length, and acoustic energy to that of a conventional SWL waveform, but does not generate cavitation. Furthermore, we have found a way to enhance the violence cavitation collapse, as well as a way to confine cavitation to a highly localized volume. We propose to use these various discoveries and tools to ascertain to ascertain the relative roles of cavitation and shear in stone comminution and tissue damage. We have also made considerable progress toward the development of a set of theoretical models that would permit us to compute the SWL waveform at any position and time, either in vitro or in vivo. Furthermore, give a specific waveform, we can compute the response of the cavitation field to this waveform, and determine, albeit in a crude way, the potential for cavitation damage in a variety of in vitro and in vivo environments. We propose to test our hypotheses by undertaking a series of experiments in which we will apply SWL to various in vitro and in vivo models, during which we will use our cavitation detection techniques to determine the presence and location of this cavitation; later, we shall correlate the tissue damage with either the presence or absence of cavitation. We shall also undertake a series of similar experiments involving stone comminution. Using these results, we shall use our theoretical models to design a waveform that would optimize stone comminution and minimize tissue damage.