PHYSICAL ASPECTS OF CAVITATION IN EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY

体外冲击波碎石术中空化的物理方面

• 批准号: 6105481
• 负责人: LAWRENCE A CRUM
• 金额: $ 16.12万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-04-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6105481
• 关键词: animal tissue; biophysics; human tissue; iatrogenic disease; imaging /visualization /scanning; kidney function; lithotripsy; luminescence; mathematical model; mechanical pressure; model design /development; nephrolithiasis; photography; physical process; sound frequency; ultrasonography; ultrasound biological effect

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.

尽管SWL已经在临床上使用了超过15年， 石头沟通的物理机制仍然不好 明白然而，现在有越来越多的实验证据 以及临床社区逐渐普遍接受的SWL 对治疗的肾脏造成一定程度的永久性损伤。的 导致这种组织损伤的机制也不太好 明白我们假设声空化是一个主导因素 结石粉碎和肾损伤都有可能竞争机制是 SWL冲击波在组织中产生的剪切应力。声空化 是空化气泡的生长和剧烈溃灭的结果 由SWL声波波形产生。我们开发了一套 先进的实验工具，使我们能够检测空化在一个 广泛的环境和一定程度的空间和时间 分辨率利用这些工具，我们获得了大量的 有证据表明，SWL在两种情况下都会产生空化， 肾实质和人肾的收集系统。我们还 发现了一种改进电动液压碎石机的方法， 产生具有类似冲击波振幅，脉冲长度， 和声能，但不 产生空化。此外，我们还找到了一种方法， 暴力空化崩溃，以及一种方法，以限制空化， 高度局部化的体积。我们建议利用这些不同的发现， 确定空化和剪切的相对作用的工具 结石粉碎和组织损伤我们也取得了可观的 一系列理论模型的发展， 允许我们在任何位置和时间计算SWL波形， 体外或体内。此外，给定一个特定的波形，我们可以计算出 空化场对此波形的响应，并确定， 尽管是以一种粗略的方式，在各种不同的情况下， 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： 进行了一系列的实验，我们将SWL应用于各种 在体外和体内模型，在此期间，我们将使用我们的空化 检测技术，以确定这种存在和位置， 空化;稍后，我们将把组织损伤与 存在或不存在空化。我们亦会进行一系列 类似的实验包括石头粉碎。利用这些结果，我们 我将使用我们的理论模型来设计一个波形， 结石粉碎和组织损伤最小化。