Abstract
Akrrucr-In order to reduce artifacts due to nonstraight line wave propagation in ultrasonic computed tomography of attenuation, the use of an experimental receiving array with phase-insensitive signal processing was evaluated. A 46-element 2.25 MHz array receiver having a singleelement aperture of 1.2 mm X 1.2 mm and a center-to-center spacing of 1.4 mm was employed and projections were taken of a phantom whose refraction characteristics were controlled by temperature. Array signals were processed incoherently and attenuation projections were calculated according to the energy ratio, frequency shift, and log spectral difference methods. The resulting projections then were compared to those obtained by a 19 mm diameter 35 MHz phasesensitive single-element receiver. The phase-insensitive array response was superior to the phase-sensitive singleelement receiver, especially when the phantom became refractive. Modest improvements in the reduction of refractive errors were obtained using the energy ratio method and negligible refractive errors were observed when the frequency shift or the log spectral difference method was used.
Published Version
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