Dielectric properties of dog brain tissue measured in vitro across the 0.3–3 GHz band

Abstract

Dielectric properties of dead Greyhound female dogs' brain tissues at different ages were measured at room temperature across the frequency range of 0.3-3 GHz. Measurements were made on excised tissues, in vitro in the laboratory, to carry out dielectric tests on sample tissues. Each dataset for a brain tissue was parametrized using the Cole-Cole expression, and the relevant Cole-Cole parameters for four tissue types are provided. A comparison was made with the database available in literature for other animals and human brain tissue. Results of two types of tissues (white matter and skull) showed systematic variation in dielectric properties as a function of animal age, whereas no significant change related to age was noticed for other tissues. Results provide critical information regarding dielectric properties of animal tissues for a realistic animal head model that can be used to verify the validity and reliability of a microwave head scanner for animals prior to testing on live animals. Bioelectromagnetics. 37:549-556, 2016. © 2016 Wiley Periodicals, Inc.

Measurement and image-based estimation of dielectric properties of biological tissues —past, present, and future—

“…These variabilities are larger than the difference between data from in vivo measurements and those reported by Gabriel et al (1996c). One of the possible reasons for the discrepancies between the data of Gabriel et al (1996c) and Mohammed et al (2016) is the different tissue temperatures. Better agreement with the data of Gabriel et al (1996c) can be observed upon adjusting the grey matter conductivity data reported by Mohammed et al (2016) for the temperature using the temperature coefficients for porcine brain obtained by Schmid et al (2003a) (see appendix B).…”

“…Most of the data shown in the figures were obtained by in vitro measurements (except those for grey matter reported by Schmid et al (2003a) and Peyman et al (2007)). On the basis of the data reported by Gabriel et al (1996c), which are the most used data, the variabilities of the data were within approximately 30% for both conductivity and permittivity, except for the data reported by Bao et al (1997) and Mohammed et al (2016). These variabilities are larger than the difference between data from in vivo measurements and those reported by Gabriel et al (1996c).…”

“…One of the possible reasons for the discrepancies between the data of Gabriel et al (1996c) and Mohammed et al (2016) is the different tissue temperatures. Better agreement with the data of Gabriel et al (1996c) can be observed upon adjusting the grey matter conductivity data reported by Mohammed et al (2016) for the temperature using the temperature coefficients for porcine brain obtained by Schmid et al (2003a) (see appendix B). Comparison of the data for grey matter obtained by Gabriel et al (1996c) at 37 °C and the corresponding temperature adjusted data reported by Schmid et al (2003b) revealed that the latter shows 10%-25% higher values.…”

Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis

“…It should be noted that the electromagnetic properties of body tissues differ between ex vivo and in vivo conditions, mainly because of the tissue dehydration and ischemic effects as explained in [70]. Subject's age [54], [71], as well as the sample handling [72], temperature [58] and time from resection to measurement [69] are factors that affect the electromagnetic properties to a greater or lesser extent. Besides, there are some recent studies assessing the dielectric properties in in vivo conditions, although the number of available tissues is more limited.…”

A New Stand-Alone Microwave Instrument for Measuring the Complex Permittivity of Materials at Microwave Frequencies

“…Moreover, there is an increasing demand for dielectric properties measurements regarding different practical applications in fields like biological and chemical industries [6]- [9], agricultural research [10]- [12], or new food technologies [13]- [15]. Indeed, the study of these properties is relevant for these fields in order to ascertain the ability of dielectric materials to be processed under microwave irradiation [16].…”