14 Mar 2010

COMPILATION OF THE DIELECTRIC PROPERTIES OF BODY TISSUES AT RF AND MICROWAVE FREQUENCIES

Recent developments in the field of electromagnetic dosimetry have produced high resolution anatomically correct man and animal models from medical imaging data for use in numerical simulation exercises. The level of details is such that over 30 tissue types can be identified. The application of such models require that dielectric properties be allocated to the various tissues at all the frequencies to which the model is exposed. There is, as yet, no consensus on the dielectric data. This project is geared towards this objective. The following has been achieved in the period covered by this report:

    * Three experimental techniques were used to measure the dielectric properties of tissue in the frequency range 10 Hz to 20 GHz. Over 20 tissue types were measured over the full frequency range and over 10 others measured down to 1 MHz only.
    * Internal consistency between the three sets of data was demonstrated in the overlapping frequency regions. When measurements are made on the same sample throughout, the agreement between data sets is particularly good.
    * A comprehensive survey of dielectric data published over more than 45 years has been carried out and presented for comparison purposes. The data obtained in the course of this study fall well within the vast body of literature data where available and bridges the gaps within it.
    * To facilitate the incorporation of the dielectric data in numerical solutions, their frequency dependence was modelled to a spectrum characterised by 4 dispersion regions. This model was successfully applied to the new experimental data.
    * Finally, the conductivity of tissues below 100 Hz was estimated from the recent measurements mitigated by data from the literature and used to estimate the conductivity of the whole body and of various body parts.

The work is briefly described in this report, the data are presented in graphical and tabular format in Appendices A to D.

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The vast majority of the data is not from in vivo sources, but rather from dead flesh, hence fairly useless in terms of the biological interactions with emf and any resonance properties.

http://www.emfdosimetry.org/dielectric/Report/Report.html
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