Microwave imaging via space-time beamforming for early detection of breast cancer

A backscatter-based microwave imaging technique that compensates for frequency-dependent propagation effects is proposed for detecting early-stage breast cancer. An array of antennas is located near the surface of the breast and an ultrawideband pulse is transmitted sequentially from each antenna. The received backscattered signals are passed through a space-time beamformer that is designed to image backscattered signal energy as a function of location. As a consequence of the significant dielectric-properties contrast between normal and malignant tissue, locations corresponding to malignant tumors are associated with large energy levels in the image. The effectiveness of these algorithms is demonstrated using simulated backscattered signals obtained from an anatomically realistic MRI-derived computational electromagnetic breast model. Very small (2 mm) malignant tumors embedded within the complex fibroglandular structure of the breast are easily detected above the background clutter.