Transmission-Type Ultrasonic Inverse Scattering Computed Tomography Using Observation Data on Circular Arc Points

Abstract

Transmission-type inverse scattering computed tomography for reconstructing both sound speed and attenuation images using the observation data along circular arc points was explored. To date, there has been difficulty in reconstructing the attenuation image, but not the sound speed image, since the attenuation contrast of tissue is very low compared to that of sound speed. Hence, a high-precision data observation, being tolerant to measurement noise and avoidable of spurious edge wave interference, is inevitable to realize stable attenuation image reconstruction. To this end, the present study revealed that circular arc observation method was highly superior to the conventional straight line observation. The optimum determination of circular-observation distance and angular-observation aperture was investigated through numerical examination of the attenuation image. Furthermore, an experimental phantom examination assuming actual parameters in tissues was performed. As a result, the validity of the present method was demonstrated.