Objective To study the electric impedance characteristics and to build the equivalent circuit of human glioma tissues. This paper provides the fundamental evidence for the further research on bioelectrical impedance of human glioma tissues. Methods The measurements for the electric impedance of four human glioma tissues are done by using four-probe method in the frequency range of 10Hz to 10MHz with Solartron 1260 impedance analyzer. By analyzing the frequency characteristics and reference the existing equivalent circuits of human brain tissue, the equivalent circuit model of human glioma is established. Results Within the frequency range of 10Hz to 10MHz, the module of the electric impedance decreases and the phase angle increases along with the increase of the frequency. In the frequency range of 10kHz to 10MHz, the real part of the electric impedance remains steady. However, in the frequency range of 10Hz to 10kHz, it decreases along with the increase of the frequency. The imaginary part of the electric impedance remains steady in the frequency range of 20kHz to 10MHz and increases along with the increase of the frequency in the frequency range of 10Hz to 20kHz. This equivalent circuit model can describe the comprehensive characteristics of the complex impedance. Conclusions There are distinct differences of electric impedance characteristics and equivalent circuit between human glioma tissues and human brain tissues, which provide the basis for further research on the application of bioelectrical impedance in distinguishing human glioma tissues and human brain tissues.
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