Accurate in vivo dielectric properties of liver from 500 MHz to 40 GHz and their correlation to ex vivo measurements

ABSTRACT

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 and are within experimental uncertainty, and therefore changes between in vivo and published ex vivo dielectric properties can be attributed to tissue hydration.

KEYWORDS:

• Complex permittivity
• Cole–Cole equation
• ex vivo
• in vivo
• in situ
• liver

Acknowledgments

This article has been motivated by discussions within the framework of COST Action TD1301, MiMed. The authors would like to thank Martin O'Holloran and Finn Krewer from National University Ireland, Galway, for using the genetic algorithm.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.