Dielectric Properties Characterization From 0.5 to 50 GHz of Breast Cancer Tissues

TLDR

Dielectric properties of human tissues are critical for imaging, hyperthermia, and safety policy, yet data above 20 GHz for breast tissue are lacking, creating a gap that emerging millimeter‑wave technologies would benefit from filling. This study characterizes breast tissue dielectric properties over 0.5–50 GHz. Cole–Cole models were fitted to ex vivo measurements from over 220 samples of normal and tumorous breast tissue collected from more than 50 patients within 3.5 h of excision. The analysis reveals distinct frequency‑dependent dielectric differences between normal and tumorous tissues, with quantified sensitivity and specificity across the spectrum.

Abstract

Knowledge of the dielectric properties of human tissues is important for several biomedical applications, including imaging and hyperthermia treatment, as well as for determining safety thresholds in policy making. Breast tissues, both normal and tumorous, are of particular interest because of the medical and social impact of breast cancers. While experimental data is available up to 20 GHz, for higher frequencies, this information is missing, or has been extrapolated from models based on lower-frequency data. Emerging technologies and applications in the millimeter-wave region would benefit from experimental data that bridge this gap. This paper presents the characterization of dielectric properties of breast tissues for the frequency range from 0.5 to 50 GHz. Cole–Cole models are derived for normal and tumorous tissues based on experimental measurements on more than 220 tissue samples obtained at surgery ( ex vivo ) from a population exceeding 50 patients, covering a wide span of normal and tumorous tissues, from patients ranging in age from 28 to 85 years, with a time from excision to measurements under 3.5 h. This paper also presents a comprehensive analysis of the differences between normal and tumorous breast tissues at different frequencies in terms of sensitivity and specificity.