Currently, many ultrasound simulations of medical imaging modalities, like IntraVascular UltraSound (IVUS) are performed using the Field II software. This software models scattering bodies as collections of point-scatterers and evaluates the resulting total pressure field within the Born approximation. Consequently, it assumes a constant speed of sound throughout the volume. Therefore, modeled reflections arrive at incorrect times, and errors are introduced if thickness measurements are performed from simulated data. In addition, multiple scattering is neglected in this approximation, which means that for strong contrasts results obtained with Field II are incomplete. To circumvent these issues, we have developed software which efficiently computes the total pressure field within a volume due to scattering off contrasts of arbitrary shape and magnitude. The software uses a conjugate gradient (CG) scheme to solve, in the temporal Laplace domain, the scatter integral equation for the total field, given known sources and contrasts. Spatial domain decomposition is used to allow for large domains of which the memory load would otherwise exceed the amount of memory present in current machines. To avoid reflections on domain boundaries, Perfectly Matched Layers (PMLs) are applied in the temporal Laplace domain. We will compare the simulated received signals, using both programs, for an acoustic probe measuring plaque thickness in an artery and show that our software yields better results in certain situations compared to results obtained with the Field II software.
展开▼
