Utilizing Spherical Resonances for Microwave Breast Cancer Detection

In this paper, we investigate if external resonances created at a spherical tumor model can be utilized to increase the contrast between the tumor and background field in a simple microwave breast imaging scenario. Numerical simulations are being performed for two cases, low-adipose and high-adipose average breast tissue, exhibiting high and low permittivity and dielectric losses, respectively. The electric field is probed along the breast surface with and without a spherical tumor model present, and the relative tumor signal with respect to the background field is separated into a surface-normal and surface-parallel component. It is shown that in the high-adipose case, an external spherical resonance is created at the tumor, whereas no clear resonance occurs in the low-adipose case. In both cases is the contrast between the tumor signal and the background field stronger in the surface-normal than in the surface-parallel component. The external tumor resonance could directly be observed in the high-adipose case as a decrease of field strength close to the tumor if placed in close proximity to the breast surface.