Contrast-enhanced microwave breast imaging

Abstract

Tomographic maps of the dielectric distribution of breast tissue can be made at microwave frequencies by applying nonlinear optimization techniques to the electromagnetic inverse scattering problem. There is a mismatch between the resolution of UHF band microwaves and the feature size of fibroconnective and glandular breast tissues which fundamentally limits the ability of such imaging systems to clearly resolve these structures. Tumor detection is further challenged by the small intrinsic contrast between the dielectric properties of normal and malignant glandular tissues. The use of contrast agents to preferentially alter the properties of malignant tissues is a potential approach to improving detection performance. In this paper, we explore the information available to contrast-enhanced imaging of realistic numerical breast phantoms at microwave frequencies. Differential images are produced using three-dimensional tomographic reconstructions of the dielectric profiles before and after the introduction of a contrast agent to a malignant inclusion.