CAVITATION MONITORING AND CONTROL IN LITHOTRIPSY

冲击波碎石术(SWL)是治疗肾结石疾病的首选治疗方法，已被广泛接受和有效。然而，随着制造商寻求提供新的和改进的设备，他们通常已经从产生具有中等高冲击波幅度的宽焦体积的单元转移到具有高冲击波幅度的紧焦体积。这种方法的目的是加强结石粉碎，减少组织损伤。然而，这些制造商似乎忽视了空化在石块粉碎或组织损伤中的作用。在过去的几年里，这个PPG团队对与SWL相关的物理和生物机制进行了广泛和全面的研究；这个特别的项目在研究 并发现它是主要的作用机制。虽然我们已经取得了很大的进展，但仍有许多不了解的地方，这项建议详细说明了我们继续探索了解SWL可以继续提供安全有效的结石治疗的物理机制。为了使我们的科学进步得到优化，我们专注于一个大方向，即将我们的发现从实验室转移到制造商。因此，在这项提案中，我们寻求改进设备和SWL方法的方法，并向制造商和公众传播关于此类改进的具体建议。为此，我们的具体目标概括如下：1)开发提供监测反馈的技术和设备 以便将空化、血流和结石粉碎实时提供给临床医生；2)使用我们的双脉冲碎石机来测试我们的假设，即定位和加强空化场将在最大程度粉碎结石，同时将组织损伤降至最低；3)确定碎石机冲击波或空化簇坍塌产生的力在结石内部产生的最大应力；4)测量冲击波波形的各个分量的单独影响，并根据此知识设计最佳波形；5)通过引入气泡内蒸发的影响来扩展我们的空化模型能力，并根据这些研究得出SWL对自由基生成水平的估计。

Shock wave lithotripsy (SWL) is the treatment of choice for renal stone disease and has been a widely accepted and effective treatment. However, as manufacturers seek to deliver new and improved devices, they have generally migrated from units that produce broad focal volumes with moderately-high shock wave amplitudes to tight focal volumes with high shock wave amplitudes. This approach is intended to enhance stone comminution and reduce tissue injury. However, it appears that these manufacturers have discounted the role of cavitation in either stone comminution or tissue injury. Over the past several years, this PPG team has undertaken a broad and comprehensive study of both the physical and the biological mechanisms associated with SWL; this particular project has made considerable progress in examining the role of cavitation and find it to be the dominant mechanism of action. Although we have made much progress, there is still much that is not understood, and this proposal details our continued search to understand the physical mechanisms through which SWL can continue to provide a safe and effective treatment for stone disease. In order for our scientific progress to be optimized, we have concentrated on a general direction meant to transition our discoveries from the laboratory to the manufacturer. Accordingly, in this proposal we seek ways to improve the devices and the approaches to SWL and to disseminate to manufacturers and the general public specific recommendations for such improvements. To this end, our specific aims are summarized as follows: 1) to develop techniques and devices that would provide monitoring feedback on cavitation, blood flow, and stone comminution to clinicians in real-time 2) to use our dual-pulse lithotripter to test our hypothesis that localizing and intensifying the cavitation field will maximize comminution while minimizing tissue injury; 3) to determine whether lithotripter shock waves or the forces produced by cavitation cluster collapse produce the greatest stresses within the stone; 4) to measure the individual effects of the various components of the shock-wave waveform and from this knowledge, design an optimal waveform; and 5) to expand our cavitation model capability by introducing the effect of evaporation within the bubble, and from these studies, obtain estimates of the level of free radical production by SWL.