Spectrum analysis of microwave breast examination data and reconstructed images

A broadband microwave tomographic imaging system is being developed for breast cancer detection which exploits the significant electrical property contrast between normal and malignant tissue. The improved image reconstruction algorithm directly processes the log-magnitude and phase values of the measured fields with the frequency rich data set being utilized to acquire the absolute scattered phase terms, especially when multiple wrapping has occurred. In addition, a lower contrast coupling medium has been selected which alleviates certain problems associated with the phase unwrapping task but also appears to reduce artifacts associated with higher permittivity contrasts between the surrounding coupling medium and the breast. Sequences of multi-plane image sets from a low contrast medium examination of a 53 year old woman over a broad frequency range are presented to illustrate the general consistency of the images over the range and to demonstrate the improved resolution at the higher frequencies.