Dielectric Properties of Body Tissues: Home page

An Internet resource for the calculation of the

Dielectric Properties of Body Tissues

in the frequency range 10 Hz - 100 GHz

ITALIAN NATIONAL RESEARCH COUNCIL

Institute for Applied Physics

Nello Carrara - Florence (Italy)

Overview

The need for extensive data on the dielectric properties of human tissues is often and strongly felt among scientists and researchers involved in the interactions of electromagnetic (EM) fields and biological systems.
Numerical dosimetry, for instance, (the discipline devoted to calculate, by means of numerical algorithms, current densities and specific absorption rates (SARs) in tissues and organs of individuals exposed to EM fields) deals with digitized 2D or 3D human models each element of which (pixel in 2D and voxel in 3D models) has to be recognized as being constituted by a given, well defined tissue and thus must have assigned unique dielectric properties, consisting of a pair of values, one for the relative permittivity and one for the electrical conductivity at each frequency of interest.
This application is aimed to calculate the dielectric properties of human body tissues in the frequency range from 10 Hz to 100 GHz using the parametric model and the parameter values developed by C.Gabriel and collegues (see Credits and References below).
It is based on a client-server approach.
The server program runs in background on a central system and is responsible for the management of the parameter database (14 parameters for each defined tissue) and for the calculation of the dielectric properties of requested tissues at requested frequencies. These properties comprise the relative permittivity, the electrical conductivity and a few significant derived quantities: the loss tangent, the wavelength and the penetration or skin depth.
The client program is executed by the user on a remote system connected to the server by a Local or a Wide Area Network supporting the TCP/IP protocol; the client program implements the user interface and translates user requests into commands for the server; it also has to deal with reception and display of the requested data.
The main advantage of the client/server approach consists in the centralized management of the tissue parameters, allowing new tissues to be defined or parameter values to be changed without having to redistribute software to the users. The users, on their sides, get also rid of the need to implement the code for the calculation of the dielectric properties from the parameter values.
The availability of the server documentation makes it possible, for users who need it and can afford it, to develop their own applications devoted to specific tasks or platforms.
The reverse of the medal obviously is the need of a TCP/IP link between the client and the server.

Credits

This application has been prepared at IFAC-CNR (ex IROE-CNR) as a side project among the activities of the research line devoted to Protection against exposures to low-frequency, radiofrequency and microwave electromagnetic fields. It would not have been possible without the huge work of C.Gabriel and collegues at the Brooks Air Force Base (USA), who developed the parametric model for the calculation of the dielectric properties of body tissues we use here (see References below).
At IFAC-CNR, the following people took part in the project:

Daniele Andreuccetti: Project design and management; mathematical background; parametric data processing; HTML, PHP and C/C++ coding.
Roberto Fossi and Caterina Petrucci: Research and critical review of bibliographic data on the dielectric properties of body tissues.

This website and the results of its analysis may be used freely for scientific purposes and for any other use permitted by law. Those who use this website should mention it in their own publications as follows:

D.Andreuccetti, R.Fossi and C.Petrucci: An Internet resource for the calculation of the dielectric properties of body tissues in the frequency range 10 Hz - 100 GHz. IFAC-CNR, Florence (Italy), 1997. Based on data published by C.Gabriel et al. in 1996. [Online]. Available: http://niremf.ifac.cnr.it/tissprop/

References

International

K.S.Cole and R.H.Cole: Dispersion and absorption in dielectrics: I. Alternating current characteristics., Journal of Chemical Physics, April 1941, pp.341-351.
C.Gabriel and S.Gabriel: Compilation of the Dielectric Properties of Body Tissues at RF and Microwave Frequencies,
Internet document; URL: http://www.dtic.mil/dtic/tr/fulltext/u2/a305826.pdf (authorized mirror at http://niremf.ifac.cnr.it/docs/DIELECTRIC/home.html). See, in particular, Appendix C: modelling of the data (authorized mirror here).
C.Gabriel: Compilation of the dielectric properties of body tissues at RF and microwave frequencies, Report N.AL/OE-TR- 1996-0037, Occupational and environmental health directorate, Radiofrequency Radiation Division, Brooks Air Force Base, Texas (USA), June 1996.
C.Gabriel, S.Gabriel and E.Corthout: The dielectric properties of biological tissues: I. Literature survey, Phys. Med. Biol. 41 (1996), 2231-2249.
S.Gabriel, R.W.Lau and C.Gabriel: The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz, Phys. Med. Biol. 41 (1996), 2251-2269.
S.Gabriel, R.W.Lau and C.Gabriel: The dielectric properties of biological tissues: III. Parametric models for the dielectric spectrum of tissues, Phys. Med. Biol. 41 (1996), 2271-2293.

in Italian

D.Andreuccetti e R.Fossi: Proprietà dielettriche dei tessuti umani: definizioni, modello parametrico, codici di calcolo, Report N.TR/ICEMM/13.00, IFAC-CNR, Firenze (I), settembre 2000.
Documento disponibile on-line all'indirizzo: http://niremf.ifac.cnr.it/tissprop/document/tissprop.pdf