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A comparison of the dielectric behaviour of pure water and human blood at microwave frequencies

1952; IOP Publishing; Volume: 3; Issue: 8 Linguagem: Inglês

10.1088/0508-3443/3/8/302

2057-7656

H Cook,

Electrical and Bioimpedance Tomography

Methods used to measure the complex dielectric constant of water and blood at frequencies from 1.7 × 109 to 2.4 × 1010 c/s are described. The results obtained for water at temperatures between 0 and 60° C are given and analysed with relation to the Debye and the Cole-Cole dispersion equations. The possibility that the dispersion in water is characterized by a narrow spectrum of relaxation times is briefly discussed. The complex dielectric constant of whole human blood has been measured at temperatures between 15 and 35° C. The dispersion observed is attributed entirely to water relaxation. It is shown to fit the Debye dispersion equations if the effects of a frequency-independent ionic conductivity are allowed for. Comparison of the results for blood with those for water leads to approximate estimates of the erythrocyte intracellular ionic conductivity and haemoglobin hydration.