Time Reversal Beamforming for Microwave Breast Cancer Detection

Microwave radiation is well known as a diagnostic imaging method for many medical applications, for example, early stage breast cancer detection. Microwave detection of breast tumors is a non-ionising, potentially low cost, in vivo modality that relies on the dielectric contrast between healthy and malignant breast tissues. The scattering environment in a breast often appears to be inhomogeneous due to changing dielectric properties of the breast tissues. Time reversal (TR) is an adaptive waveform transmission scheme that utilizes the rich scattering medium to best match to the target response. In this paper, we develop the microwave time reversal beamformer for breast tumor detection. The TR beamforming scheme is examined based upon a breast model using the two-dimensional finite-difference time-domain (FDTD) method. We show that time reversal microwave beamforming is a more robust, higher resolution imaging scheme than conventional beamforming schemes.