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Millimeter wave dosimetry of human skin
Author(s) -
Alekseev S.I.,
Radzievsky A.A.,
Logani M.K.,
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.20363
Subject(s) - dermis , bioelectromagnetics , stratum corneum , human skin , penetration (warfare) , penetration depth , materials science , epidermis (zoology) , biomedical engineering , absorption (acoustics) , optics , extremely high frequency , anatomy , composite material , pathology , medicine , physics , mathematics , genetics , quantum mechanics , operations research , biology , magnetic field
To identify the mechanisms of biological effects of mm waves it is important to develop accurate methods for evaluating absorption and penetration depth of mm waves in the epidermis and dermis. The main characteristics of mm wave skin dosimetry were calculated using a homogeneous unilayer model and two multilayer models of skin. These characteristics included reflection, power density (PD), penetration depth (δ), and specific absorption rate (SAR). The parameters of the models were found from fitting the models to the experimental data obtained from measurements of mm wave reflection from human skin. The forearm and palm data were used to model the skin with thin and thick stratum corneum (SC), respectively. The thin SC produced little influence on the interaction of mm waves with skin. On the contrary, the thick SC in the palm played the role of a matching layer and significantly reduced reflection. In addition, the palmar skin manifested a broad peak in reflection within the 83–277 GHz range. The viable epidermis plus dermis, containing a large amount of free water, greatly attenuated mm wave energy. Therefore, the deeper fat layer had little effect on the PD and SAR profiles. We observed the appearance of a moderate SAR peak in the therapeutic frequency range (42–62 GHz) within the skin at a depth of 0.3–0.4 mm. Millimeter waves penetrate into the human skin deep enough (δ = 0.65 mm at 42 GHz) to affect most skin structures located in the epidermis and dermis. Bioelectromagnetics 29:65–70, 2008. © 2007 Wiley‐Liss, Inc.