Ultrasonic absorption tomography on soft tissues with correction for scattering effects
Résumé
Among the many factors involved in ultrasound attenuation phenomena scattering effects play a particularly important role, even in the case of the soft tissues studied here. It is proposed in this study to isolate these effects before proceeding with the reconstruction of the absorption parameter alone. The procedure used for this purpose consists first in reconstructing the sound speed distribution (constituting the absorption free model), using a transmission tomography algorithm. A numerical propagation (FEM) code processing the absorption free phantom then generates realistic scattering distortions that serve as reference signals when applying the log spectral difference method. The scattering effects are thus removed from the integrated absorption projections measured. The latter are processed using a tomographic procedure that provides an estimate of the absorption distribution. Numerical simulations show the improvement obtained in the absorption contrast estimates thanks to this method.