高强度聚焦超声声压测量中非线性声场对激光干涉系统带宽的影响  

Influence of Nonlinear Sound Field on Bandwidth of Laser Interferometry Systems in High-Intensity Focused Ultrasound Pressure Measurements

作　　者：王珂 杨平[1] 邢广振 Wang Ke;Yang Ping;Xing Guangzhen(Division of Mechanics and Acoustics Metrology,National Institute of Metrology,Beijing 100029,China)

机构地区：[1]中国计量科学研究院力学与声学计量科学研究所,北京100029

出　　处：《中国激光》2023年第13期55-62,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(11904347);国家市场监督管理总局计划项目(2021MK151);中国计量科学研究院基本科研业务费(AKYCX2210)。

摘　　要：针对激光干涉法高强度聚焦超声(HIFU)声压测量中干涉系统带宽解算依赖线性声场条件,导致解算结果与实际有较大差异的问题,首先通过理论分析,建立了HIFU声压测量中干涉信号的数理模型;针对非线性声场条件下干涉信号无法进行函数展开的情况,利用数值仿真的方法对干涉信号的频域进行分析;通过对比具有相同声压峰峰值和基频的线性和非线性声场条件下的干涉信号频谱,发现了非线性声场对激光干涉信号带宽的展宽作用,证明了现有线性声场条件下干涉系统带宽的估算方法不适用于HIFU声压测量;利用实测HIFU声压数据,通过仿真分析,发现在非线性声场条件下,激光干涉系统带宽随被测声压峰峰值呈二次方规律变化,而不是线性声场条件下的线性变化规律。Objective High-intensity focused ultrasound(HIFU) is a non-invasive medical thermal ablation technology that can realize the “noninvasive” treatment of diseases.It is developing into a standard tumor treatment method.The accurate measurement of the HIFU sound pressure is very important for formulating clinical schemes involving HIFU treatment and ensuring the safety and effectiveness of the treatment.Laser interferometry has been adopted by new-generation sound pressure benchmarks because of its high precision,non-contact characteristic,and direct traceability to the length benchmark.The bandwidth of a laser interference system directly affects the upper limit of sound pressure measurements.Current methods of estimating system bandwidth are based on linear sound field conditions;however,with an increase in the measured sound pressure,the HIFU field will become nonlinear,leading to a deviation between the system bandwidth requirements and the model solution results.Aiming to address the problem of bandwidth calculation of interference systems for HIFU sound pressure measurement,this study theoretically analyzes a mathematical model of interference system bandwidth and vibration signal in HIFU sound pressure measurement,refers to the measured sound pressure value,and establishes the relationship between interference system bandwidth and sound pressure by numerical simulation.Methods According to the mathematical relationship between sound particle vibration and interference signal,a bandwidth model of interference signals under the condition of a nonlinear sound field is established.Because the interference signal is expressed as a nonelementary function that cannot be expanded by the Bessel function,the bandwidth of the interference signal under the condition of a nonlinear sound field is analyzed by numerical simulation.The simulation results show that compared with that in a linear sound field,the interference signal spectrum in a nonlinear sound field is not symmetrically distributed centered on the carrier

关 键 词：测量 高强度聚焦超声 声压测量 激光干涉系统带宽 非线性声场 

分 类 号：TH741[机械工程—光学工程]