FDTD analysis of planar and cylindrical antenna-array configurations for 3D breast tumor localization using confocal microwave imaging

Breast cancer screening using the confocal microwave imaging (CMI) technique proposed by S.C. Hagness et al. (see IEEE Trans. Biomed Eng., vol.45, p.1470-9, 1998) involves illuminating the breast with an ultra-wideband pulse from a number of physical antenna locations and collecting the backscattered signals. Using a simple, robust image reconstruction technique that achieves a synthetic focusing of the backscatter, the clutter generated by breast tissue heterogeneity can be suppressed, permitting the detection and localization of strong scatterers (malignant lesions) in the breast. Two possible antenna-array configurations have been proposed for CMI. In the planar configuration, the woman to be scanned lies on her back and resistively loaded bow tie antennas are placed at the surface of the naturally flattened breast. In the cylindrical configuration, the woman lies on her stomach with the breast naturally extending through a hole in the examination table and encircled by an array of resistively loaded dipole antennas. We compare the planar and cylindrical antenna-array systems using similar breast models and image reconstruction algorithms. Backscatter data are simulated using the finite-difference time-domain (FDTD) method.