磁性纳米粒子的磁声谐波成像研究  

Magnetoacoustic Harmonic Imaging Based on Magnetic Nanoparticles

作　　者：黄洋[1] 曹睿杰 郭各朴[1] 马青玉[1] 郭余庆 王军[2] Huang Yang;Cao Ruijie;Guo Gepu;Ma Qingyu;Guo Yuqing;Wang Jun(School of Computer and Electronic Information/School of Artificial Intelligence,Nanjing Normal University,Nanjing 210023,China;Jiangsu Nengjian Electromechanical Industrial Co.,Ltd,Taizhou 225327,China)

机构地区：[1]南京师范大学计算机与电子信息学院/人工智能学院,江苏南京210023 [2]江苏能建机电实业集团有限公司,江苏泰州225327

出　　处：《南京师大学报（自然科学版）》2022年第2期1-8,共8页Journal of Nanjing Normal University(Natural Science Edition)

基　　金：国家自然科学基金重点项目(11934009);国家自然科学基金面上项目(11974187,12174198);南京师范大学课程思政教改项目(2021NSDJG028).

摘　　要：磁性纳米粒子(MNPs)具有良好的磁响应、生物相容性和降解性等优点,在早期肿瘤诊疗中得到了广泛应用.本文基于MNPs在交变磁场激励下的磁声谐波响应,利用锥形磁芯的汇聚作用,开展了基于MNPs的磁声谐波成像研究.首先构建锥形磁芯的电磁激励模型,产生了具有大磁场强度/梯度分布的磁场区域,并基于MNPs的磁矩、机械振动和声传播研究了有效磁场区域内粒子的声辐射特性,推导了磁声谐波响应声压公式,实现了基于磁声谐波声压的二维扫描成像;然后研究了非理想锥尖条件下平顶高度对有效磁场区域半径、声压以及穿透深度的影响,结果表明非理想锥尖可以提高磁声谐波响应和穿透深度,但会一定程度降低谐波成像分辨率;最后利用环形坡莫合金的磁屏蔽效应来减小有效磁场区域,提高MNPs谐波成像的分辨率和对比度,在生物组织的浅表成像中展现良好的应用价值.Due to the advantages of the good magnetic response,biocompatibility and biodegradability,magnetic nanoparticles(MNPs)have been widely used in early tumor diagnoses and treatments.In this paper,an imaging method based on the magnetoacoustic harmonic response of MNPs is studied by introducing the convergence effect of a conical iron cone.Firstly,the electromagnetic excitation model with a conical core is constructed to generate a focused effective magnetic field of high magnetic field intensity and its gradient.Based on the theories of the magnetic moment,mechanical vibration and acoustic radiation of MNPs,the magnetoacoustic harmonic pressure is analyzed and derived.Then,by considering the possible phenomena of a non-ideal cone tip,the influence of the flat top on the size of the effective magnetic volume,acoustic pressure and penetration depth is studied.The favorable results show that the non-ideal cone-tip model can be used to increase the pressure of the magnetoacoustic harmonic response with a deeper penetration,while leading to a decreased imaging accuracy to a certain extent.Finally,by introducing the magnetic shielding effect of a toroidal permalloy,the spatial resolution and the contrast of the magnetoacoustic harmonic imaging are further improved,exhibiting prosperous application potentials in the superficial imaging for biological tissues.

关 键 词：磁声谐波成像 磁性纳米粒子 锥形磁芯 坡莫合金 

分 类 号：O441.3[理学—电磁学]