Experimental Study of Dielectric Properties on Human Lung Tissue

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1 Chinese Journal of Biomedical Engineering Vol. 32 No. 2 April * Agilent 4294A 100 Hz ~ 100 MHz Cole-Cole 3 ~ ~ 3. 3 R α τ f c P < EIT R318 A Experimental Study of Dielectric Properties on Human Lung Tissue WANG Jie-Ran 1 WANG Hua-Xiang 1* XU Xiao 2 1 Institute of Electrical Engineering and AutomationTianjin UniversityTianjin China 2 Department of RadiotherapyGeneral Hospital of Tianjin Medical UniversityTianjin China Abstract This study is aim to investigate the differences of dielectric properties between lung cancer tissue and the normal tissue in vitro and establish the dielectric parameter frequency spectrum of human lung tissue which provide the basic theory and reference data for medical research and clinical diagnosis of lung cancer. Two main categories of tissues were considered as specimens the central part of the tumor and the normal tissue around the tumor. After operationspecimens was put into test chamber in which the temperature and humidity were controlled at expected values. Then the measurement of specimens dielectric properties was performed at frequency from 100 Hz to 100 MHz using 4294A impedance analyzer of Agilent Company. Finally the two categories of tissues characteristic parameters were extracted by using the least square curve fitting method based on Cole-Cole model. The relative permittivity of lung cancer tissue was 3 ~ 5 times larger than that of the normal tissue. The conductivity of lung cancer tissue was 1. 6 ~ 3. 3 times larger than that of the normal tissue. Impedance spectroscopy of lung cancer tissue moved apparently to low impedance direction. Among the characteristic parameters R α τandf c the difference of low frequency resistance between the two categories of tissues was statistically significant P < The differences of dielectric properties and low frequency resistance between lung cancer tissue and the normal tissue are significantwhich provide basic data for human lung tissue s dielectric properties research and EIT measurement. Key words dielectric properties impedance spectroscopy lung cancer tissue characteristic parameters doi / j. issn JCYBJC JCYBJC03500 * hxwang@ tju. edu. cn

2 a R m C m R i C i X R e C e CT R m electrical impedance tomographyeit C i C e 1 b 2 EIT EIT 19 Gabriel a 100 b Fig. 1 Equivalent circuit models of biological Hz ~ 100 MHz tissue. a The original one b The Cole-Cole simplified one 1 11 Z = R + - R jωτ τ = R i + R e C m = R e 30 R i R e R = 2 R 30 i + R e Cole 30 min 30 Cole-Cole 12 R R Z = R ( jωτ) 1 - α 1. 2 ω = 0 R 0 R ω = τ α 0 ~ 1 α = 0 2 f c f c = 1 /2πτ

3 Fig. 2 2 Cole-plot of biological tissue Fig. 4 Environment platform of the dielectric PC spectrum measurement system Agilent A GPIB PC Matlab Labview 5 mm 12 mm C = - 1 /2πfX 4 ε r = Cd / ε 0 S A σ = d / RS 6 3 d S R C X f ε 0 ε 0 = F / m SPSS Kruskal-Wallis 3 30 Fig. 3 Dielectric spectrum measurement Kruskalplatform of human lung tissues Wallis α = t P < Cole-Cole x i y i i 2 N N x 0 y 0 r % 100 Hz ~ 100 MHz Q x 0 y 0 r = N 槡 x i - x y i - y 0 - r

4 2 181 a = - 2x 0 b = - 2y 0 c = x y r 2 8 Q a b c = N x 2 i + c 2 9 a b c a = 0 b = 0 c = ~ 10 a = N 2 x 2 i + c x i = 0 11 b = N 2 x 2 i + c y i = 0 12 c = N 2 x 2 i + c = 0 13 a b c x 0 = - a /2 y 0 = - b /2 r = 1 /2 槡 a 2 + b 2-4c 14 3 ~ 5 1 ~ 100 khz b 100 khz 100 Hz ~ 100 MHz ~ S / m ~ S / m 100 Hz ~ 1 khz 1 khz 3. 3 = x + r 2 2 槡 - y 15 R = x - r 2 2 槡 - y 16 α = 2 π arcsin ( y r ) 17 τ = 1 1 / 1 - α 1 - Z i ω i N N ω i ( Z i ω i - R ) 18 ω i 5 a 2 b Fig. 5 Dielectric spectrum properties of lung cancer tissue and the normal tissue. a Relative permittivity b Conductivity Kruskal-Wallis 2. 3 P > Cole-Cole 1 khz ~ 10 MHz a 1 khz ~ 10 MHz 1 khz

5 ~ R α τ f c 6 Fig. 6 Cole-plot of lung cancer tissue and 1 the normal tissues Tab. 1 Fitting circle parameters of lung tissue x y r 14 ~ 18 P > t P < ± ± ± ± ± ± P Tab. 2 2 Characteristic parameters of lung tissue / Ω R / Ω α τ 10-7 f c / MHz 1280 ± ± ± ± ± ± ± ± ± ± P R α τ f c 42942A EIT Jemal ABray FCenter MMet al. Global cancer statistics J. CA Cancer J Clin Hz ~ 100 MHz 2. J Gabriel CGabriel SCorthout E. The dielectric properties of biological tissues I. Literature survey J. Phys Med Biol Gabriel SLau RWGabriel C. The dielectric properties of biological tissues II. Measurements in the frequency range 10 Hz 3 ~ 5 to 20 GHz J. Phys Med Biol ~ Gabriel SLau RWGabriel C. The dielectric properties of biological tissues III. Parametric models for the dielectric spectrum of tissues J. Phys Med Biol EIT Hz ~ 10 MHz J

6 D. 10Xiao FunianOtto KCamarillo IG. The dielectric properties of International Conference on the Properties and Applications of J Taehong KJunhurt OBongseok Ket al. A study of dielectric properties of fattymalignant and fibro-glandular tissues in female human breast. C/ / Electromagnetic Compatibility and 19th International Zurich Symposium on Electromagnetic Compatibility2008. APEMC Asia-Pacific Symposium on May electroporated human breast cancer cells. C/ / IEEE 10th Dielectric Materials ICPADM Bangalore IEEE J Cole KSCole R H. Dispersion and absorption in dielectrics J. J Chen Phys M

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