Microwave system for breast tumor detection: experimental concept evaluation

A microwave system for breast cancer detection has been modeled numerically (see Fear, E.C. and Stuchly, M.A., IEEE Trans. Microwave Theory Tech., vol.48, p.1854-63, 2000). This system is based on the principle of confocal microwave imaging (CMI). In our system, a woman lies in the prone position with the breasts immersed in a liquid (low loss, dielectric constant similar to that of breast tissue). One or more antennas are mechanically scanned around the breast, forming a synthetic array. A short pulse containing a broad range of frequencies (5 GHz or more) is transmitted from each antenna position and the same antenna receives a scattered pulse. Numerical simulations of the system performance show that tumors of the order of 3 mm diameter can be detected and located. In the simulations, a contrast of about 5 in dielectric constant and 10 in loss factor is used for the normal and malignant breast tissues. In order to verify our cylindrical CMI system experimentally, a test system has been designed to image analogous contrasts in the dielectric constant of representative materials. Results of the experiment and associated signal processing are presented.