Simulation checks in ultrasonic computed tomography.

The contribution presents some results obtained on the way to checking (and partly complementing) the standard reconstruction procedures in USCT by wave-equation based simulations. Mathematical models emerging from the transparent physical background for both the surrounding fluid and the object tissue are presented, followed by the present results of developing a realistic original finite-element-method based simulation. With respect to the need of comparison with the calibration measurements, a preliminary optimization of initial guesses to boundary conditions at the transducer array is discussed, based on a point-source model.

Comparison of wave-equation versus measurement-processing transducer calibration for ultrasonic transmission tomography.

The contribution deals with the first step in using proper wave-equation based ultrasound propagation model in image reconstruction from the ultrasonic computed tomography data. Particularly, it compares the transducer calibration results obtained via direct measurement of the empty image field and consequential data processing based on a simple direct-propagation model with the simulation results obtained via solving the single-frequency wave equation under proper border conditions reflecting the realistic measurement geometry. The results show a reasonable qualitative agreement when a certain degree of phase-shifted coupling from the transmitting transducer elements to the neighbouring elements of the transducer field is admitted.