Applications of microwave imaging to three-dimensional biological tissues

The conventional X-ray mammography measures the attenuation of the breast tissue. The low attenuation contrast between tumor and background results in a high false alarm rate at clinically accepted detection rates. Microwave breast imaging techniques have been proposed over the past few years because of their potentially high specificity for breast cancer diagnosis due to the high contrast in electrical properties between normal and malignant human breast tissues. For example, at 800 MHz, the contrast is 3.75 for the relative permittivity, and 6.75 for the electrical conductivity. This high contrast gives rise to a large electromagnetic scattering signal when electromagnetic waves are applied to a malignant tumor embedded in normal tissue. We develop a nonlinear inverse scattering algorithm to unravel multiple scattering effects for 3D microwave imaging. This algorithm is applied to form high resolution three-dimensional images to simulate an experimental prototype of a microwave breast imaging system.