In this article, we report on the characterization of the dielectric properties of in vivo rat liver at 36.4°C from 500 MHz up to 40 GHz with less than 5% uncertainty. The measured data were fitted to a Cole-Cole model and dielectric parameters are presented together with their respective 95% confidence interval. The root mean square error is 0.42. Moreover, ex vivo measurements were conducted in situ at 1, 2, 4 and 6 min after animal death and are compared to in vivo measurements. The results show that immediate changes in [Formula: see text]and [Formula: see text] are within experimental uncertainty, and therefore changes between in vivo and published ex vivo dielectric properties can be attributed to tissue hydration.

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An investigation of the variation of dielectric properties of ovine lung tissue with temperature.

The dielectric properties of biological tissues are fundamental pararmeters that are essential for electromagnetic modeling of the human body. The primary database of dielectric properties compiled in 1996 on the basis of dielectric measurements at frequencies from 10 Hz to 20 GHz has attracted considerable attention in the research field of human protection from non-ionizing radiation. This review summarizes findings on the dielectric properties of biological tissues at frequencies up to 1 THz since the database was developed. Although the 1996 database covered general (normal) tissues, this review also covers malignant tissues that are of interest in the research field of medical applications. An intercomparison of dielectric properties based on reported data is presented for several tissue types. Dielectric properties derived from image-based estimation techniques developed as a result of recent advances in dielectric measurement are also included. Finally, research essential for future advances in human body modeling is discussed.

The aim of this study was to characterize the hydration fractions of biological tissues and to model these accurately from mixture equations. Hydration fractions, better known as volume fractions, are based on quantification of tissue hydration and accurate knowledge about the physiological composition of tissue fluids. Data on weight loss percentages for excised muscle and adipose tissue from a previous study were utilized for this purpose. The Bruggeman and Maxwell Garnett equations were then used to characterize the dielectric properties of the tissues in terms of mixtures of dry biological constituents and physiological saline solutions. It is shown that these models are accurate in modelling in vivo and ex vivo tissue in different states of hydration. This is based on precise knowledge of the physiological composition of biological fluids and their corresponding percentage contents. RECEIVED