Pulse-Echo Ultrasound Simulation in 3D Aberrating Media
Intervening tissue layers (Fig. 1) can be a major obstacle for obtaining clear ultrasonic images in echographic systems with large array transducers. Various correction methods have been proposed to obtain better images for these cases1-.4 In order to test the applicability and limits of the correction methods, it is important to have an accurate and efficient computational model describing the propagation through these distorting tissue layers. The sound propagation through tissue is often modeled as the propagation through a layer consisting of a cascade of thin sublayers, where each sublayer acts upon the incident wave as a random time-shift operator.5 Various papers5-,7 however, report that the wave modification can not be described sufficiently with these models and that refraction effects also should be taken into account. In particular, ultrasound propagation through female breast5’7 suffers from severe refractive errors. In abdominal animal tissue6 strong multi-path components were noticed, with refraction as a possible cause. Recently, therefore, we have tried to come up with an efficient numerical method8 to model the process of refraction, which is attacked by solving the numerical problem of wave propagation through an irregular interface between two uniform media. Of course, the present model should be extended with distributed wave aberrations to get a more complete description of wave propagation through human tissue.
KeywordsPoint Scatterer Rough Interface Ultrasonics Symposium Preconditioned Scheme Cylindrical Interface
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