Dielectric properties of female human breast tissue measured in vitro at 3.2 GHz

Abstract

Complex permittivities of in vitro diseased and undiseased human female breast tissues have been measured at 3.2 GHz using a resonant cavity technique. Ranges of dielectric properties and water contents of these tissues are presented. Experimental data are compared with models predicted from mixture equations. Measured permittivity data lie within limits set by two-phase mixture theory, but some conductivity data are in excess of those expected for a mixture of saline and protein. At any particular microwave frequency in all tissue of a given type, the relationship between permittivity and conductivity may be parametrized using the Debye relaxation equations. For each breast tissue type a characteristic relaxation frequency was calculated and found to be lower than that of physiological saline at the same temperature. It is concluded that the dielectric relaxation of tissue water is not the only dispersive process occurring at this frequency: dielectric relaxation of bound water and the tail end of a beta-dispersion may also contribute to the dielectric properties. The similarity of the dielectric properties of benign and malignant breast tumours measured in this work suggest that in vivo dielectric imaging methods will not be capable of distinguishing them.

Numerical Modelling for Ultra Wideband Radar Breast Cancer Detection and Classification

“…Furthermore, the estimations of dielectric properties in scenario (iii) also agreed well with previous ex vivo studies such as [37,38,40,42]. However, Haemmerich et al [43] observed a change in some dielectric parameters after excising tissue and attributed those changes to variations of temperature, tissue dehydration and ischemic effects.…”

“…• The dielectric data spanned a much greater range of values than those reported in previous studies, with the exception of Campbell and Land's study [38].…”

“…Overall, Lazebnik attributed these differences to the large heterogeneity in normal breast tissue, as previously noted in [38], and acknowledged the relationship between fibroglandular content and average dielectric properties.…”

MARIA M4: clinical evaluation of a prototype ultrawideband radar scanner for breast cancer detection

“…17 Initial results of microwave radar-based imaging have been presented [17][18][19][20][21][22][23] and approaches rely on a difference in the dielectric properties (Dk) of normal and malignant breast tissues. [24][25][26][27][28][29][30][31] The breast as an organ is unique in the human body in that basic structure consists of glandular tissue (high dielectric constant, high conductivity, and radioopaque) in a fat (low dielectric constant, low conductivity, and relatively radiolucent)-based matrix. Inclusions, such as a tumor, are also of high permittivity, enhanced by the angiogenic increase in vascularity, and cysts contain fluid, which also have very high permittivity.…”

Dielectric Studies of Corn Syrup for Applications in Microwave Breast Imaging

“…The measured data is compared with the available literature data on normal, benign and malignant breast tissues [14] and is given in Table 1. Good agreement is observed.…”