NSF/FDA Scholar-in-Residence at FDA: Nonlinear Derating in Pre-Clinical Testing of High-Intensity Focused Ultrasound Systems

1041508 Banerjee本研究的长期目标是改进HIFU换能器的表征方法。本申请的目的是测试一种非线性降额方法，该方法可以预测高功率下HIFU光束的热效应。本研究的中心假设是，可以通过在水中进行测量并使用非线性降额方法来量化组织中的生物效应来估计组织中焦点体积内的温升。他们计划通过追求两个特定目标来测试假设并实现目标：1）在给定水中振幅的情况下，推导用于评估组织中压力模式振幅的算法。工作假设是，将压力模式振幅从水转换为组织振幅的降额算法将是准确的，并且当插入温度模式的表达式时，将能够评估组织体模中的温升;以及2）使用热电偶在组织体模中使用逆传热方法评价降额方法。工作假设是，组织模型中的测量，结合逆方法，可以验证降额算法。本研究的预期结果是一种用于确定器械热有效性和安全性的独特方法，该方法准确、低成本且适用于临床相关功率。该方法预计将产生重要的积极影响，提供一种工具，将加快新的HIFU系统的临床前测试，有利于超声设备行业和FDA的审查。

1041508BanerjeeThe long-term goal of this research is to improve characterization methods for HIFU transducers. The objective of this application is to test a nonlinear derating method that can predict the thermal effects of HIFU beams at high powers. The central hypothesis of this research is that temperature rise within the focal volume in tissues can be estimated by performing measurements in water and using a nonlinear derating method to quantify bioeffects in tissues. They plan to test the hypothesis and accomplish the objective by pursuing the two specific aims: 1) To derive algorithms for assessing the amplitudes of pressure modes in tissue, given the amplitudes in water. The working hypothesis is that a derating algorithm for converting pressure mode amplitudes from water to amplitudes in tissue will be accurate and that, when inserted into the expression for temperature modes, will enable assessment of temperature rise in a tissue phantom; and 2) To evaluate the derating approach with inverse heat-transfer method in tissue phantoms using thermocouples. The working hypothesis is that measurements in tissue phantoms, combined with inverse method, can validate the derating algorithm. The expected outcome of this study is a unique method for establishing the thermal efficacy and safety of the devices that is accurate, low-cost, and applicable at clinically relevant powers. The method is expected to have an important positive impact by providing a tool that will expedite the preclinical testing of new HIFU systems, benefitting both the ultrasound device industry and FDA reviewers.