Development of Biological Ultrasonic Micro-Specroscopy System

生物超声显微波谱(Bio-UMS)系统是在VHF和UHF范围内对生物软硬组织进行微观表征的一种新的研究工具，建立了一种测量生物软组织样品在反射和传输模式下的声速、衰减和密度等体声学特性的方法，该方法将生物软组织样品夹在两端带有氧化锌压电薄膜换能器的熔融石英缓冲杆的平行表面之间。该方法是一种以蒸馏水为参比介质的声传输线比对方法。为了获得较高的测量精度，涉及到两杆表面平行度的精密机械对准技术、运动调整间隙距离技术和信号处理技术。给出了牛肝脏、心肌和脂肪组织的测量结果。反射式生物软…声学显微镜系统已经开发了更多的组织表征。该系统在幅度和相位两种模式下工作，可以测量二维彩色成像中组织的声学特性，即速度和衰减，也可以测量成像区域中任意点的声学特性。由福尔马林固定的石蜡包埋标本制备的狗心肌梗死组织的演示已经制作完成。定量测定了病理退变引起的组织声学特性的空间变化。本文还提出了一种修正的定量表征模型，其中考虑了样品的声多次反射和粘度的影响。以牙科材料为例，讨论了声学显微镜研究生物硬组织的粘弹性特性。线聚焦波束(LFB)声学显微镜的定量应用以及点聚焦波束(PFB)声学显微镜的成像应用已经令人满意地证明了这种可能性。特别是，LFB声学显微镜有望在解决各种牙科材料的基本和实际问题方面发挥重要作用，这些材料包括牙釉质和牙本质的牙科硬组织，以及用于修复人类牙齿的牙科瓷器和复合材料。较少

A biological ultrasonic micro-spectroscopy (Bio-UMS) system has been developed as a new research tool to characterize biological soft and hard tissues on a microscopic scale in the VHF and UHF ranges.A method has been developed for measuring the bulk acoustic properties such as velocity, attenuation, and density in reflection and transmission modes with the biological soft tissue specimen sandwiched between the parallel surfaces of fused quartz buffer rods having ZnO piezoelectric film transducers on their opposite ends. The method is an acoustic transmission line comparison method wherein the reference medium is distilled water. Techniques of precise mechanical alignment for parallelism of the two rod surfaces, movement to adjust the gap distance, and signal processing are involved in order to obtain high measurement accuracy. Results of measurements with bovine tissues of liver, heart muscle, and fat have been presented.A reflection-type acoustic microscope system for biological soft … More tissue characterization has been developed. This system operates in both amplitude and phase modes, and can measure acoustic properties, viz., velocity and attenuation, of tissues in two-dimensional color imaging, as well as at arbitrary points in an imaging area. A demonstration for dog cardiac infarcted tissues prepared from a formalin-fixed, paraffin-embedded sample has been made. Spatial hanges of acoustic properties in tissues due to pathological degeneration were quantitatively determined. A revised model for the quantitative characterization has been also proposed wherein the effects of acoustic multiple reflection and viscosity of the sample have been taken into account.Acoustic microscopy has been discussed to investigate viscoelastic properties of biological hard tissues, taking dental materials. The quantitative applications of an line-focus-beam (LFB) acoustic microscope, as well as the imaging applications of a point-focus-beam (PFB) acoustic microscope, have satisfactorily demonstrated the possibilities. In particular, the LFB acoustic microscope can be expected to play an important role as a powerful tool to solve basic and practical problems in all kinds of dental materials, including dental hard tissues of enamel and dentine, and dental porcelains and composites for repairing human teeth. Less