Experimental Tests of Microwave Breast Cancer Detection on Phantoms

Abstract

We report on experimental tests of microwave breast cancer detection using the radar-based imaging method and breast phantoms, i.e., structures whose size and shape are similar to reality, and whose electric properties are close to those known for the normal and tumoral tissues. Different antennas have been designed, fabricated and tested in operation in the experimental setup. Measurements were carried out in the frequency domain, with transient response synthetically obtained via numerical processing of data. We have found that alcohol is a useful coupling medium, and devised a practical arrangement to avoid contact between the breast and such a medium. We propose a new algorithm to reduce the sensitivity of the reconstruction algorithm to the assumption of the propagation velocity of the wave in the background and in the normal tissue. In our experiments, the contrast between the media simulating normal and tumoral tissues was between 1.65 and 2.45 in permittivity and 0.45 to 1.45 in conductivity. We were able to correctly detect tumor-simulating obstacles with 1 cm diameter, without false positives. We have found that the band below 1 GHz was of paramount importance for the correct imaging, while we did not observe significant advantages in including the band between 1 and 9 GHz.