Three-dimensional finite-difference time-domain scattering and computed tomography in microwave medical imaging.

摘要

Microwave medical imaging has the advantage that it provides different functional information from other kinds of imaging and therefore is a useful diagnostic tool. Central to this is the study of physiologic and pathophysiologic correlations in isolated organs maintained by extracorporeal circulation. Imaging with microwaves offers a view of biosystems function which is unparalleled by other imaging modalities.; Microwave propagation depends on the permittivity (molecular) rather than density based interactions of the incident energy with tissue structure when compared with X-ray radiation. The new concept of using microwave computed tomography (MCT) instead of the traditional X-ray CT, ultrasound CT, and MRI is being investigated via computer simulations utilizing FDTD methods.; Microwave imaging has some advantages over impedance imaging. Results prove that differential imaging of tumors can be achieved better with microwave imaging. From the comparison among the four methods of electric field, magnetic field, conduction current, and SAR; the method of electric fields performs best in determining the size and location of tumors across three different types of renal tumor models. This dissertation has produced reliable simulation data for an in-vitro and in-vivo MCT system design to image the kidneys of Dachshund dogs.; MCT systems offer economy of space and low construction cost considerations along with computational advantages which make such systems a compelling choice for medical imaging.; An additional novel contribution is on 4-D visualization of FDTD volumetric data in virtual reality. Visualization literally makes the unseen world of electromagnetics visible.