兔离体新鲜肝组织的电阻抗温度特性研究

Electric Impedance Temperature-resistant Characteristics in Fresh Rabbit Liver in Vitro

目的:获得肝组织的电导率与温度的关系,为采用电阻抗成像法监测在肝肿瘤热疗时的体内温度奠定基础。方法:采用新鲜离体兔肝,通过模拟肝肿瘤热疗过程,四电极法阻抗盒测量兔肝在受热和冷却的2个阶段的多频电阻抗,研究兔肝组织的电阻抗与温度间的相应关系。结果:在58℃以下、f=1 kHz时,温度-电阻抗变化系数基本上在-1.0%～-2.2%波动。在58～69℃区间,温度-电阻抗变化系数从-2%快速变化至-14.7%。69、70、71℃等3个温度点的温度—电阻抗变化系数均保持在-14.7%附近。在71～76℃区间,温度-电阻抗变化系数从-14.7%快速变化至-1.0%。76℃以上,温度-电阻抗变化系数基本上为-1.0%。结论:兔肝细胞受热变性时电阻抗特性发生显著改变。在临床热疗中,有可能通过监测生物阻抗的改变来监测热疗时的温度。

Objective To obtain the relationship between conductivity and temperature of liver tissue in order to lay a foundation for monitoring the body temperature during the liver tumor thermotherapy with Electrical Impedance Tomography（EIT）.Methods By simulating the course of liver tumor thermotherapy,the multi-frequency electrical impedance of fresh rabbit liver was measured by the four-electrode impedance box in the process of heating and cooling.The corresponding relationship of temperature and electrical impedance of rabbit liver was calculated.Results At the frequency of 1KHz,with temperature below 58℃,the Temperature-Impedance Variation Factor（TIVF）mainly fluctuated between-1.0%～-2.2%.From 58℃ to 69℃,TIVF rapidly changed from-2.0% to-14.7%.At 69℃,70℃ and 71℃,TIVF maintained around-14.7%.From 71℃ to 76℃,TIVF changed rapidly from-14.7% to-1.0%.TIVF was mainly-1% at temperature above 76℃.Conclusion Significant changes of electrical impedance characteristics occur when liver cells are denaturized by hyperthermia.In clinical therapy,it is possible to monitor temperature in hyperthermia by monitoring the changes of bio-impedance.