Speaker: Timothy E. Doyle, Dept. Physics, Utah State University

Title: Simulation of Ultrasonic Scattering at the Cellular Level: New Tools for Disease Detection and Treatment

Abstract: Future advances in ultrasound-based medical therapies and diagnostic methods will rely less on macroscopic interactions and more on interactions with cells and tissues at the microscopic level. To better understand these interactions, models have been developed to simulate wave propagation in tissues at the cellular level. These models incorporate effects due to cell structure, tissue structure, multiple scattering, and the elastic properties of the cell and tissue components (nucleus, cytoplasm, and extracellular matrix). The programs developed to date approximate the cells and nuclei as spherical particles, and model multiple scattering both inside and outside the cells using vector multipole methods. Recent results are presented for simulations of up to 2100 cells, and show that neoplastic changes such as nuclear pleomorphism and tissue disorganization significantly affect specific ultrasonic features in backscatter spectra. The models provide a mechanistic link between measurable parameters in medical ultrasound and histological changes associated with various tissue pathologies. The application of these results to the improvement of ultrasonic tissue characterization and the specificity of various ultrasonic imaging modalities are discussed, as well as future plans for improving the histological accuracy of the models.