微波致热超声信号时频特征及其影响因素  

The Characteristics and Affects of the Microwave-Induced Thermo-Acoustic Signals in Time and Frequency Domain

作　　者：陈国平[1,2] 于万宝[1] 赵志钦[1] 聂在平[1] 柳清伙[1,3] 

机构地区：[1]电子科技大学电子工程学院,四川成都610054 [2]重庆邮电大学通信学院,重庆400065 [3]电子与计算机工程系,Duke,University,durhamnc27708

出　　处：《电子学报》2010年第3期689-694,共6页Acta Electronica Sinica

基　　金：国家自然科学基金(No.60771042;60728101;60927002);四川省杰出青年学科带头人培养计划(No.08ZQ026-039);新世纪优秀人才支持计划项目;高等学校学科创新引智计划(No.B07046)

摘　　要：微波致热超声成像是一种兼顾了微波和超声成像两方面长处的新型生物医学成像方法.本文首先给出了一个微波致热超声(Microwave-Induced Thermo-Acoustic,MITA)实验系统,然后结合信号理论和MITA机制,讨论微波脉冲激励源和样品尺寸这两方面因素对MITA信号的时域波形和频域分布的影响.由实验数据和理论分析得出MITA信号时域波形强度与入射微波脉冲宽度和样品截面大小成正比;MITA信号的频率分布除了与激励微波脉冲频谱有关外,更主要的特性是其频谱分布中心与样品厚度所确定的超声波本振频率存在对应关系.Microwave-induced thermo-acoustic（MITA）Tomography is a promising technique in medical imaging area.It is a combination of the microwave and ultrasound techniques.In this paper,an experimental system of MITA is briefly presented.The mechanism of MITA and some signal processing methods are applied in analyzing the characteristics and affects of the MITA signals.The affects,the irradiated microwave pulse and the geometry of the tissue are studied.Experiment results and theoretic analysis show that the amplitude of the time domain MITA signals are proportional to the intensity of the irradiated microwave pulse and the cross-section of the sample.The spectrum distribution of the MITA signals are not only affected by the spectrum of the irradiated microwave,but also affected by the intrinsic frequency determined by the tissue＇s thickness.The center frequency of the MITA signals recorded in experiment accord with this hypothesis.

关 键 词：微波致热超声 信号特征 时频域分析 

分 类 号：Q684[生物学—生物物理学]