Studies on bioultrasonic micro-spectroscopy

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Bioultrasonic micro-spectroscopy (Bio-UMS) is expected to be developed as a new methodology in the research fields of biological science and medical applications. Viscoelastic properties of biological soft and hard tissues on a microscopic scale can be investigated by Bio-UMS technology using bulk and focused ultrasonic waves in the VHF and UHF ranges. Systems and methods for Bio-UMS have been developed as follows :1. A bioultrasonic spectroscopy method and system, operating in the frequency range from 1MHz to 1GHz, has been developed in order to obtain bulk acoustic properties of soft tissues and liquids using longitudinal waves. The frequency characteristics of attenuation, velocity, and impedance, and the density can be determined simultaneously with high accuracy by an ultrasonic transmission comparison method wherein the reference medium is water.The acoustic properties of attenuation, velocity, impedance, and density of castor oil, silicone oil, and conttonseed oil have been dete … More rmined in the range 2 to 500MHz by the system. Measurements of velocity dispersion have been demonstrated successfully for the oils in the range 20 to 300MHz.Four paramenters of bovine liver, heart muscle, and fat have been determined simultaneously for the first time in the range 20 to 200MHz. It has been shown that the differences between the acoustic properties of liver and heart muscle tissues can be explained by their protein contents.2. A method and system to determine acoustic properties using shear waves has been developed. The shear wave properties of glycerol and silicone oil have been obtained in the range 5 to 300MHz with sufficient accuracy.3. A new method and system has been developed to obtain nonlinear properties of liquids in the VHF and UHF ranges using ultrasonic longitudinal waves. Nonlinear parameters have been determined for aqueous solutions of sugars in the fundamental frequency range 100 to 180MHz for the first time.4. A high resolution directional point-focus-beam acoustic microscope system with two functions of imaging and quantitative measurements has been developed to in investigate hard tissues of teeth and bones. Less