生物组织介电特性测量系统的设计与应用OA

Objective To design an integrated system for real-time dielectric property measurement of biological tissues based on the initial coaxial probe method,analyze the accuracy of the system in measuring the dielectric properties of tissues,and study the influence of probe pressure on the measurement of dielectric properties.Methods Based on components such as single-chip microcomputers,pressure sensors,and signal processing circuits,a reflection coefficient and probe pressure measurement device was constructed.The upper computer software with calibration and dielectric properties calculation functions was developed to display the probe pressure and dielectric property measurement tissue in real time.After the measurement system was established,the dielectric properties of methanol,n-propanol,liver phantom,glioma and normal brain tissue were measured,and the dielectric properties of the tissues measured by this system were verified based on standard parameters such as the coefficient of dispersion,average percentage error and relative difference.Results The average dispersion coefficients of the relative dielectric constant and electrical conductivity of methanol within the sweep frequency range were 0.0026 and 0.0827,respectively.The average percentage errors were 0.85%and 16.01%,respectively.The average dispersion coefficients of the relative dielectric constant and electrical conductivity of n-propanol within the sweep frequency range were 0.0028 and 0.0078,respectively.The average percentage errors were 2.43%and 14.38%,respectively.The relative differences in dielectric constants between glioma tissue and normal brain tissue at frequencies of 64,128 and 298 MHz were 57.28%,48.97%and 48.85%,respectively.The relative differences in electrical conductivity were 73.61%,69.9%and 66.26%,respectively.Conclusion This system can be used for real-time in vitro measurement of dielectric properties of biological tissues,and at the same time provides a reference for studying the influence of probe pressure on the measurement of dielectric properties.