Supercomputer Technology for Ultrasound Tomographic Image Reconstruction: Mathematical Methods and Experimental Results

This paper is concerned with layer-by-layer ultrasound tomographic imaging methods for differential diagnosis of breast cancer. The inverse problem of ultrasound tomography is formulated as a coefficient inverse problem for a hyperbolic differential equation. The scalar mathematical model takes into account wave phenomena, such as diffraction, refraction, multiple scattering, and absorption of ultrasound. The algorithms were tested on real data obtained in experiments on a test bench for ultrasound tomography studies. Low-frequency ultrasound in the 100–500 kHz band was used for sounding. An important result of this study is an experimental confirmation of the adequacy of the underlying mathematical model. The ultrasound tomographic imaging methods developed have a spatial resolution of 2 mm, which is acceptable for medical diagnostics. The experiments were carried out using phantoms with parameters close to the acoustical properties of human soft tissues. The image reconstruction algorithms are designed for graphics processors. Architecture of the GPU cluster for ultrasound tomographic imaging is proposed, which can be employed as a computing device in a tomographic complex.