【摘要】 目的:研究生物活性组织高频段介电特性测量手段以及建模分析方法 ,为人体活性组织介电特性研究提供指导。方法:在1 MHz~120 MHz频段上利用终端开路同轴探头对家兔肝脏、肌肉与肾脏组织进行单端口反射测量,并通过相位相消法解决工作频段下同轴探头的相位标校问题。根据简化后的等效电路模型对测量结果进行分析计算,最后得出被测组织在各频点下的介电特征参数,并将结果与阻抗测量得到的数据进行对比。同时,利用Cole-Cole方程对被测组织介电特性进行数据拟合分析。结果:通过与阻抗测量得到的数据对比证明,终端开路同轴能够在高频段内对生物组织介电特征参数进行很好的检测。同时,相位相消能够解决终端开路同轴探头在工作频段内相位标校问题,得到较好的测量结果。实验结果表明,含水量相当的组织介电特性在高频段内比低频段内更为接近,从一个方面验证了高频段组织内部水的极化与介电色散对组织介电特性分布的影响;此外,根据测量数据的Cole-Cole方程曲线拟合结果推测:不同生物同种类型组织的介电特性差异主要体现在Cole参数的弛豫部分。结论:通过理论分析与实测结果证实了终端开路同轴探头测量生物活性组织介电特性,并且利用Cole-Cole方程进行数据拟合进而分析生物组织介电特性的可行性,对今后更为深入的研究具有一定帮助。更多还原

【Abstract】 Objective To study the in vivo measurement and analysis method of dielectric properties of biological tissues in high frequency band and provide some directions for the in vivo study of dielectric properties of human. Methods This study made one port reflection measurement on the rabbit’s liver, muscle and kidney tissues using open-ended coaxial probe in the frequency ranged from 1 MHz to 120 MHz. The phase calibration problem of open-ended coaxial probe in working frequency band was solved by the phase cancellation method. The dielectric properties of tissues at different frequencies were calculated according to the simplified equivalent circuit model and compared with the results of impedance measurement. On the other hand, the Cole-Cole equation was used to fit the curve of measurement data and analyze the dielectric properties of biological tissues under test. Results Judging from the results compared with data of impedance measurement, the open-ended coaxial probe could measure the dielectric properties of biological tissues in high frequency band well. Also, the phase calibration problem of the open-ended coaxial probe could be also solved well by phase cancellation method. And the measurement data shows that the biological tissues which contain the same water content have more similar dielectric properties in high frequen-cy than low frequency which shows the conclusion dispersion and polarization of water in tissues takes more interference on dielectric property in high frequency. What is more, it is also found by the Cole-Cole equation curve fitting that the difference among the tissues of different species are shown on the relaxation parts of the Cole parameter. Conclusion The principle analysis and measurement results validate the feasibility to apply open-ended coaxial probe for measurement of dielectric properties of biological tissues and the feasibility to apply the Cole-Cole equation for measurement data fitting and analysis of dielectric properties of biological tissues, which may be helpful for the further study.更多还原