Advanced acoustic field measurements of shock wave lithotripters

描述(申请人提供)：本项目的目标是使用线性水听器阵列测量冲击波碎石机(SWL)的瞬时声场。所有以前的SWL声场测量都是使用单元件水听器进行的，只有在声场不随冲击而变化的情况下才有效。具体地说，我们建议1)基于为高频成像阵列开发的技术制造线性水听器阵列，2)对阵列进行电学和声学表征，3)驱动阵列以确定耐久性，4)在SWL器件中测试阵列以提高对瞬时声场的理解。建议的测量将代表SWL声场的第一个瞬时“快照”，并将对碎石机设备设计、结石粉碎的理论模型、设备校准和患者管理具有广泛的影响。SWL被用于非侵入性治疗肾结石已有近25年的历史，在需要医疗干预的情况下，H50%的治疗都使用了SWL。根据国家糖尿病、消化和肾脏疾病研究所的数据，20岁至74岁的成年人中有5.2%患有肾结石，H17.1万成年人每年需要住院接受“肾结石和输尿管结石”的治疗。尽管“改进”的SWL系统已经上市，但最初的Dornier HM3仍然被认为是治疗的黄金标准。然而，当在单点测量时，HM3的声场变化高达50%。这种变化被认为可以改善结石的碎裂，但它也增加了对周围肾组织造成创伤的可能性。建议的线性水听器阵列将由Ketterling博士在RRI制造。最初的阵列设计将有20个单元，跨度为18毫米。在RRI验证了阵列的基本操作后，将制造更多的阵列，并将其发送给波士顿大学的克利夫兰博士和华盛顿大学的贝利博士。然后，这些阵列将被用于对三种主要类型的SWL系统进行第一次瞬时声场测量：电液压碎石机、电磁碎石机和压电式碎石机。这些测量将提供有关瞬时声场的尺寸和峰值压力位置、不同反射器对声场的影响以及新电极和旧电极性能的重要信息。该项目的成功结果最终将有助于通过更有效的结石粉碎来提高临床疗效，并通过减少组织损伤来提高临床安全性。公共卫生相关性：这项工作的最终目标是提高冲击波碎石术(SWL)治疗肾结石的疗效，方法是更有效地粉碎结石，同时将周围的肾脏组织暴露在最小的创伤中。建议的测量将是首次对SWL系统进行瞬时声场测量，并将提供有价值的信息，可用于改进碎石机设备、结石粉碎的理论模型、设备校准和患者管理。

DESCRIPTION (provided by applicant): The goal of this project is to measure the instantaneous acoustic field of shock wave lithotripters (SWL) using a linear hydrophone array. All previous measurements of SWL acoustic fields have been performed with single-element hydrophones which are only effective if the sound field does not vary from shock to shock. Specifically, we propose to 1) fabricate linear hydrophone arrays based on techniques developed for high-frequency imaging arrays, 2) characterize the arrays electrically and acoustically, 3) drive the arrays to failure to determine durability, and 4) test the arrays in SWL devices to improve the understanding of the instantaneous acoustic field. The proposed measurements would represent the first instantaneous "snapshot" of an SWL acoustic field and would have broad implications for lithotripter device design, theoretical models of stone fragmentation, device calibration, and patient management. SWL has been employed for nearly 25 years to non-invasively treat kidney stones and is utilized in H 50% of the treatments when medical intervention is required. According to the National Institute of Diabetes and Digestive and Kidney Diseases, 5.2% of adults aged 20 to 74 have had kidney stones and H 171,000 adults require a hospital stay each year to undergo treatment of "calculus of kidney and ureters." Even though "improved" SWL systems have come to market, the original Dornier HM3 is still considered the gold standard in treatment. However, the acoustic field of the HM3, when measured at a single point, varies by as much as 50%. This variation is thought to improve stone fragmentation but it also increases the likelihood of trauma to the surrounding kidney tissue. The proposed linear hydrophone array will be fabricated at RRI by Dr. Ketterling. The initial array design will have 20 elements and span 18 mm. After validating the basic operation of the array at RRI, additional arrays will be fabricated and sent to Dr. Cleveland at Boston University and Dr. Bailey at the University of Washington. The arrays will then be employed to make the first instantaneous acoustic field measurements of the three major classes of SWL systems: electrohydraulic, electromagnetic, and piezoelectric lithotripters. The measurements will yield important information about the dimensions and peak pressure location of the instantaneous acoustic field, the effect on the acoustic field of different reflectors, and the performance of new versus old electrodes. A successful outcome of this project will, ultimately, help improve clinical efficacy through more efficient stone fragmentation and improve clinical safety by reducing tissue damage. PUBLIC HEALTH RELEVANCE: The ultimate goal of this work is to improve the efficacy of shock wave lithotripsy (SWL) treatment of kidney stones by more efficiently fragmenting the stones while exposing the surrounding kidney tissue to minimal trauma. The proposed measurements would represent the first instantaneous acoustic field measurements of SWL systems and would provide valuable information that could be used to improve lithotripter devices, theoretical models of stone fragmentation, device calibration, and patient management.