Experimental and Finite-Difference Time-Domain Simulation Study of the Precise Measurement of the Gonad of a Small Fish Using a 25-MHz Acoustic Focus Probe

Abstract

A high-resolution imaging method using a 25-MHz ultrasonic acoustic profile measurement was introduced, and the inner structures of small fish were examined without body contact. Two types of fish were selected as experimental targets and measured using a focused probe. 3-D acoustic imaging of the inner and external structure of the fish body was then performed, and the results demonstrated that the visualization of main organs (e.g., stomach, intestine, airbladder, and spine) was possible and a small gonad could be detected. In addition to these experiments, finite-difference time-domain simulation was introduced for complex wave propagation phenomena in the fish body, providing a clear understanding of the experimental data.