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Reflection and penetration depth of millimeter waves in murine skin
Author(s) -
Alekseev S.I.,
Gordiienko O.V.,
Ziskin M.C.
Publication year - 2008
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.20401
Subject(s) - stratum corneum , permittivity , bioelectromagnetics , debye–hückel equation , materials science , penetration depth , reflection (computer programming) , dermis , penetration (warfare) , skin effect , extremely high frequency , optics , skin barrier , human skin , biomedical engineering , dielectric , anatomy , chemistry , optoelectronics , pathology , physics , medicine , dermatology , mathematics , electrolyte , computer science , genetics , biology , quantum mechanics , magnetic field , programming language , electrode , operations research
Millimeter (mm) wave reflectivity was used to determine murine skin permittivity. Reflection was measured in anesthetized Swiss Webster and SKH1‐hairless mice in the 37–74 GHz frequency range. Two skin models were tested. Model 1 was a single homogeneous skin layer. Model 2 included four skin layers: (1) the stratum corneum, (2) the viable epidermis plus dermis, (3) fat layer, and (4) muscle which had infinite thickness. We accepted that the permittivity of skin in the mm wave frequency range results from the permittivity of cutaneous free water which is described by the Debye equation. Using Fresnel equations for reflection we determined the skin parameters best fitting to the reflection data and derived the permittivity of skin layers. The permittivity data were further used to calculate the power density and specific absorption rate profiles, and the penetration depth of mm waves in the skin. In both murine models, mm waves penetrate deep enough into tissue to reach muscle. In human skin, mm waves are mostly absorbed within the skin. Therefore, when extrapolating the effects of mm waves found in animals to humans, it is important to take into account the possible involvement of muscle in animal effects. Bioelectromagnetics 29:340–344, 2008. © 2008 Wiley‐Liss, Inc.