Etoz Sevde, Brace Christopher L
Department of Biomedical Engineering, University of Wisconsin - Madison, Madison, WI 53706 USA.
Departments of Radiology and Biomedical Engineering, University of Wisconsin - Madison, Madison, WI 53706 USA.
IEEE J Electromagn RF Microw Med Biol. 2019 Jun;3(2):105-110. doi: 10.1109/jerm.2018.2881692. Epub 2018 Nov 16.
We propose dielectric tissue property models dependent on both water and air content covering the microwave frequency range. Water is the largest constituent of biological tissues and its effect on the dielectric properties of biological tissue has been studied. However, dehydration effects due to thermal heating have not been fully characterized. We combined 1) Maxwell-Fricke mixture theory with a four-pole Cole-Cole equation to include water and air content dependency and as the second approach a different 2) Maxwell mixture model was coupled with a Debye function. The proposed approaches (1 and 2) were able to predict the permittivity (') and conductivity () of bovine liver and swine lung tissues at different hydration and inflation states from 1-15 GHz. A second approach coupling Maxwell and Debye models required fewer assumptions and modelled tissue properties with higher accuracy (less than 15% mean percent error in all tissue types). These models may help improve the accuracy of microwave ablation simulation when tissue water content changes as a result of vaporization, and may facilitate personalized treatment planning.
我们提出了覆盖微波频率范围的、依赖于水和空气含量的介电组织特性模型。水是生物组织的最大组成部分，并且其对生物组织介电特性的影响已得到研究。然而，热加热导致的脱水效应尚未得到充分表征。我们将1）麦克斯韦 - 弗里克混合理论与四极科尔 - 科尔方程相结合，以纳入水和空气含量的依赖性，作为第二种方法，将不同的2）麦克斯韦混合模型与德拜函数相结合。所提出的方法（1和2）能够预测牛肝和猪肺组织在1 - 15 GHz不同水合和充气状态下的介电常数（'）和电导率（）。将麦克斯韦模型与德拜模型相结合的第二种方法需要的假设更少，并且对组织特性的建模精度更高（在所有组织类型中平均百分比误差小于15%）。当组织水含量因汽化而变化时，这些模型可能有助于提高微波消融模拟的准确性，并可能有助于个性化治疗计划。
