基于肋骨为强吸声体的多层介质内非线性声场研究  

Research on nonlinear acoustic fields in multi-layer biological tissue with ribs as strong acoustic absorbers

作　　者：王浩宇 赖宁磊 晏张平 林伟军[3] 刘晓宙[1,3] WANG Haoyu;LAI Ninglei;YAN Zhangping;LIN Weijun;LIU Xiaozhou(Key Laboratory of Modern Acoustics,Institute of Acoustics and School of Physics,Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China;Chengdu HEUK Medical Equipment Co.Ltd.,Chengdu 610041,China;State Key Laboratory of Acoustics,Chinese Academy of Science,Beijing 100190,China)

机构地区：[1]南京大学,人工微结构科学与技术协同创新中心,南京大学声学研究所,近代声学教育部重点实验室,南京210093 [2]成都海克医疗设备有限公司,成都610041 [3]中国科学院声学研究所,声场声信息国家重点实验室,北京100190

出　　处：《物理学报》2025年第4期171-180,共10页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2020YFA0211400);国家自然科学基金重点项目(批准号:11834008);国家自然科学基金(批准号:12174192);声场声信息国家重点实验室开放课题研究基金(批准号:SKLA202410);水声环境特性重点实验室开放课题研究基金(批准号:SSHJ-KFKT-1701)资助的课题.

摘　　要：在使用高强度聚焦超声进行肋下病灶治疗的过程中,肋骨的遮挡显著影响了治疗的效果,在先前的研究中,肋骨通常被视作完美吸声体,这一模型虽然能够在一定程度上体现肋骨造成的影响,但也同样可能导致对肋后能量的低估.为弥补现有工作的不足,本文提出了一种将肋骨视作强吸声体、而非完美吸声体的数值计算方法,并使用ABS塑料构建的仿肋模型进行了相关实验以比较两类方法的优劣,此外本文还在多层介质模型中研究了肋骨对非线性声场造成的影响.由于肋骨在新模型中具有较大的声衰减系数,现有算法在计算过程中容易出现数值振荡问题,为此本研究使用了算子分离法以提高数值计算的稳定性,并进一步通过矩阵向量化方法在后向隐式差分格式下实现了声场的稳定求解.这些改进不仅提高了数值计算的准确性,还揭示了完美吸声体模型造成的肋后能量低估问题,对于优化临床治疗策略具有重要意义.During the treatment of subcostal lesions with high intensity focused ultrasound(HIFU),the obstruction by the ribs significantly affects the therapeutic effect,which can be assessed through numerical calculations.In existing studies,ribs are typically regarded as perfect acoustic absorbers,and even though this assumption could reveal the influence of the ribs on the acoustic field to some extent,it may still underestimate the energy behind the rib cage.In order to address the shortcomings of current work,an innovative numerical calculation method that avoids treating ribs as perfect sound absorbers is proposed in this work.Subsequently,experiments are conducted using ABS plastic rib cage mimic to compare the effectiveness between the two methods,demonstrating that the method proposed in this paper,which avoids the assumption of considering ribs as perfect acoustic absorbers,could better reveal the influence caused by ribs,and further studies are carried out on the influence of ribs in a multi-layered medium model.In response to the numerical oscillation issues encountered in existing work when dealing with media with high acoustic attenuation coefficients,the operator splitting method to enhance the stability of numerical calculations is adopted in this work.Furthermore,to tackle the challenges posed by asymmetric acoustic fields in numerical computations,in this paper matrix vectorization technique is introduced and stable solutions for the acoustic field under the backward implicit difference scheme are obtained.Additionally,when considering nonlinear effects,an asymptotic maximum number of harmonics is employed to reduce the computational load.These improvements in both the numerical calculation model and the corresponding algorithm not only enhance the precision of numerical computations,but also reveal the underestimation of energy behind the ribs due to the assumption of perfect acoustic absorbers,which is significant for optimizing HIFU treatment strategies.

关 键 词：高强度聚焦超声 算子分离法 非轴对称 矩阵向量化 

分 类 号：O42[理学—声学] R312[理学—物理]