Besler Brendon C, Baker Ryan, Shen Hua, Fear Elise C
Department of Electrical and Software Engineering, University of Calgary, Calgary, Alberta, Canada.
Department of Mathematics and Statistics, University of Calgary, Calgary, Alberta, Canada.
Bioelectromagnetics. 2025 Jan;46(1):e22534. doi: 10.1002/bem.22534.
Readily available animal tissue, such as ground beef, is a convenient material to represent the dielectric properties of biological tissue when validating microwave imaging and sensing hardware and techniques. The reliable use of these materials depends on the accurate characterization of their properties. In this work, the effect of physiologically relevant levels of dehydration on ex vivo tissue samples is quantified while controlling for variation within and between samples. Seven commercial ground beef samples (90% lean muscle, 10% fat) are dehydrated from 0.0% to 7.0% in 1.0% increments by weight. Dielectric measurements are collected using a conventional dielectric probe technique from 0.2 to 6 GHz. A linear mixed-effects model is used to control for within- and between-sample variation while modeling the effect of dehydration and dispersion across frequency. Significant ( ) changes are noted in both permittivity and conductivity due to sample dehydration. For a 1% change in weight due to dehydration, changes in permittivity (5.1%-5.6%) and conductivity (3.2%-5.7%) are reported. These changes are important for the use of large muscle-based phantoms in microwave sensing and imaging validation, as well as the feasibility of microwave hydration assessment. The statistical model used here can be applied to similar research questions and can augment existing frameworks for reporting dielectric measurements.
在验证微波成像和传感硬件及技术时，容易获取的动物组织，如碎牛肉，是一种方便的材料，可用于代表生物组织的介电特性。这些材料的可靠使用取决于对其特性的准确表征。在这项工作中，在控制样本内部和样本之间的变化的同时，对离体组织样本中与生理相关的脱水水平的影响进行了量化。七个市售碎牛肉样本（90%瘦肌肉，10%脂肪）以1.0%的重量增量从0.0%脱水至7.0%。使用传统的介电探针技术在0.2至6 GHz范围内收集介电测量数据。在对脱水和频率色散的影响进行建模时，使用线性混合效应模型来控制样本内部和样本之间的变化。由于样本脱水，介电常数和电导率均出现了显著（ ）变化。对于因脱水导致的1%重量变化，介电常数变化（5.1%-5.6%）和电导率变化（3.2%-5.7%）被报告。这些变化对于在微波传感和成像验证中使用基于大块肌肉的体模以及微波水化评估的可行性很重要。这里使用的统计模型可应用于类似的研究问题，并可扩充现有的介电测量报告框架。
