Ultrasonic Imaging in Biomedical Applications

This article describes fundamentals of ultrasonic imaging in biomedical area and general operation principles for two main types of imaging devices: scanning acoustic microscope and phased array systems. The contrast of ultrasonic images originates in variation of acoustic impedance in the sample, whereas resolution is determined by wavelength (operating frequency). Frequency analysis of reflected signal allows Doppler imaging revealing motion of cells and fluids. Advanced methods of signal acquisition and processing such as V ( z ) measurement and Fourier analysis used for tissues characterization. Quantitative parameters of soft and hard tissues (sound speed, acoustic impedance, attenuation) obtained with ultrasound may be calculated. A short review describes current state of research in soft and hard biological tissues as well as cellular structures with ultrasound. The article will be useful for wide medical and biological auditory for introduction in ultrasonic imaging.