Using Dielectric Properties of Organ Matter and Water Content to Characterize Tissues at Different Health and Age Conditions (original) (raw)
Related papers
Dielectric properties of low-water-content tissues
Physics in Medicine and Biology, 1985
The dielectric properties of two low-water-content tissues, bone marrow and adipose tissue, were measured from 1 kHz to 1 GHz. From 1 kHz to 13 MHz, the measurements were performed using a parallel-plate capacitor method. From 10 MHz to 1 GHz, a reflection coefficient technique using an open-ended coaxial transmission line was employed. The tissue water contents ranged from 1 to almost 70% by weight. The dielectric properties correlate well with the values predicted by mixture theory. Comparison with previous results from high-water-content tissues suggests that bone marrow and adipose tissues contain less motionally altered water per unit dry volume than do the previously studied tissues with lower lipid fractions. The high degree of structural heterogeneity of these tissues was reflected in the large scatter of the data, a source of uncertainty that should be considered in practical applications of the present data.
The Dielectric Properties of Biological Tissues: I
1996
The dielectric properties of tissues have been extracted from the literature of the past five decades and presented in a graphical format. The purpose is to assess the current state of knowledge, expose the gaps there are and provide a basis for the evaluation and analysis of corresponding data from an on-going measurement programme. † Present address:
The dielectric properties of biological tissues: I. Literature survey
Physics in Medicine and Biology, 1996
The dielectric properties of tissues have been extracted from the literature of the past five decades and presented in a graphical format. The purpose is to assess the current state of knowledge, expose the gaps there are and provide a basis for the evaluation and analysis of corresponding data from an on-going measurement programme.
Physics in Medicine and Biology, 1996
A parametric model was developed to describe the variation of dielectric properties of tissues as a function of frequency. The experimental spectrum from 10 Hz to 100 GHz was modelled with four dispersion regions. The development of the model was based on recently acquired data, complemented by data surveyed from the literature. The purpose is to enable the prediction of dielectric data that are in line with those contained in the vast body of literature on the subject. The analysis was carried out on a Microsoft Excel spreadsheet. Parameters are given for 17 tissue types.
Dielectric properties of the tissues with different histological structure: Ex vivo study
Journal of Experimental Biology and Agricultural Sciences
This study aimed to estimate the dielectric properties of tissues with different histological structures. For this, specimens of fibrous (n=9), muscular (n=7), and fatty (n=11) human tissues were studied. The estimation of dielectric permittivity and conductivity of these specimens was tested with a program and apparatus device for near-field resonance microwave sensing, including 5 applicators with different depths of study. Results of the study demonstrated that this technology can visualize the shape, localization, and linear decisions of biological objects. The currently used method allows distinguishing the tissue histological type. It was stated that fibrous tissue has a maximal level of median and highest dielectric permittivity, and the minimal value of this parameter was fixed for fatty specimens (in 4.26 and 4.53 times lower than in fibrous one, respectively). Muscular tissue has an intermediate value of dielectric permittivity, approaching a level close to fibrous tissue.
Physics in Medicine and Biology, 1996
Three experimental techniques based on automatic swept-frequency network and impedance analysers were used to measure the dielectric properties of tissue in the frequency range 10 Hz to 20 GHz. The technique used in conjunction with the impedance analyser is described. Results are given for a number of human and animal tissues, at body temperature, across the frequency range, demonstrating that good agreement was achieved between measurements using the three pieces of equipment. Moreover, the measured values fall well within the body of corresponding literature data.
Dielectric response of some biological tissues
Bioelectromagnetics, 2001
The dielectric properties of two freshly excised mice tissue samples (kidney, skeletal muscle) and also freshly excised Ehrlich solid tumor were measured in the frequency range from 20 Hz to 100 kHz using RLC bridges. The data were ®tted to a summation of multiple Cole±Cole dispersion and also to the constant power law which is related formally to the fractal geometries of tissues using a genetic algorithm for optimization developed by the author. The data were in good agreement with the Cole±Cole equation for the three samples. Bioelectromagnetics 22:272±279, 2001.
Effects of Blood Stream on Non-Invasive Dielectric Spectroscopy Measurements for Biological Tissues
2020
We performed complex permittivity measurements for various parts on the flexor surface of wrist by non-invasive dielectric spectroscopy technique using flat-end coaxial electrodes terminated by the tissues with different conditions of bloodstream. The dielectric measurements evaluated dynamic behaviors of ions, water, biomolecules, and various cells including red blood cells in bloodstream with dielectric relaxation processes. The dielectric relaxation curve thus obtained characterized each living tissue and indicated a decreasing tendency of the restoration from the high heart rate and the blood pressure after exercise. Using curve fitting analysis of the relaxation curve with several Cole-Cole functions, one relaxation process was identified as a process reflecting the condition of bloodstream. The present work confirms that the non-invasive dielectric measuring technique using the flat-end coaxial electrode with the fringing electric field quantitatively characterizes the condition of living tissues, and it can be an effective tool for pathology of bloodstream in vivo.