Dielectric characterization of carbon nanotube contrast agents for microwave breast cancer detection

We are investigating the feasibility of single-walled carbon nanotubes (SWCNTs) as contrast agents for microwave breast cancer detection. We hypothesize that the accumulation of SWCNTs in a tumor will enhance the dielectric contrast between normal and malignant tissue and potentially improve the efficacy of microwave imaging techniques. As an initial step, we constructed tissue-mimicking phantom materials with varying concentrations of SWCNTs. We characterized their dielectric properties and estimated the pressure wave induced in the phantom materials under microwave illumination. At SWCNT concentrations of less than 0.5% by weight, we observed significant changes in both the relative permittivity and effective conductivity of these SWCNT/tissue-mimicking material mixtures. Our estimates suggest a similarly significant change in the thermoacoustic response relative to the phantom material mixtures without carbon nanotubes.