Speed of sound evaluation considering spatial resolution in a scanning acoustic microscopy system capable of observing wide spatial area

摘要

The dependence of the speed of sound (SoS) in sliced rat organs on the spatial resolution was investigated through ultrasound analysis at high frequencies (80 and 250 MHz). The radio-frequency echo signals from target were acquired by a scanning acoustic microscopy system developed by the authors that can observe a sample with a transducer. The SoS was evaluated by correcting for the time of flight difference obtained from the wide area measurement. The dependency of the SoS on the spatial resolution was evaluated by applying different filtering methods. Stable analysis was possible after time correction, and fine textures reflecting the microstructure could be observed. The application of different filters to the results obtained at 250 MHz resulted in average SoS values that were similar to those obtained at 80 MHz. These results suggest that the primary targets evaluated 80 and 250 MHz are connective tissue and single cells, respectively. (C) 2020 The Japan Society of Applied Physics