Modeling of the dielectric properties of biological tissues within the histology region

Porter, Emily; Gioia, Alessandra La; Santorelli, Adam; O’Halloran, Martin

doi:10.1109/tdei.2017.006690

Cited by 26 publications

(19 citation statements)

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“…More recently, Porter et al demonstrated how different definitions of the sensing depth can impact the determined sensing depth value and highlighted that, for some definitions, the value does depend on the frequency and dielectric properties of the tissues occupying the sensing volume [ 83 ]. The work of Porter et al also confirmed the findings of Meaney et al, in that the experimental results demonstrated that the tissue in contact with the probe has a greater impact on the measured dielectric properties than deeper tissues [ 82 ]. Nevertheless, because the sensing volume may be affected by the intrinsic dielectric properties of the investigated sample, further experiments involving the analysis of materials with more complex structures across both radial and axial directions are needed in order to define the sensing volume accurately for complex tissue samples.…”

Section: Tissue Sample Preparation and Measurement Proceduressupporting

confidence: 55%

“…In order to define the sensing volume to account for histological analysis of heterogeneous biological tissues, Meaney et al and Porter et al examined the sensing volume of the common commercial dielectric probes and evaluated the dependence of the measured dielectric properties on the sample tissue composition [ 80 , 81 , 82 , 83 ].…”

Section: Tissue Dielectric Properties: Background and Relevant Wormentioning

confidence: 99%

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Open-Ended Coaxial Probe Technique for Dielectric Measurement of Biological Tissues: Challenges and Common Practices

et al. 2018

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Electromagnetic (EM) medical technologies are rapidly expanding worldwide for both diagnostics and therapeutics. As these technologies are low-cost and minimally invasive, they have been the focus of significant research efforts in recent years. Such technologies are often based on the assumption that there is a contrast in the dielectric properties of different tissue types or that the properties of particular tissues fall within a defined range. Thus, accurate knowledge of the dielectric properties of biological tissues is fundamental to EM medical technologies. Over the past decades, numerous studies were conducted to expand the dielectric repository of biological tissues. However, dielectric data is not yet available for every tissue type and at every temperature and frequency. For this reason, dielectric measurements may be performed by researchers who are not specialists in the acquisition of tissue dielectric properties. To this end, this paper reviews the tissue dielectric measurement process performed with an open-ended coaxial probe. Given the high number of factors, including equipment- and tissue-related confounders, that can increase the measurement uncertainty or introduce errors into the tissue dielectric data, this work discusses each step of the coaxial probe measurement procedure, highlighting common practices, challenges, and techniques for controlling and compensating for confounders.

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Section: Tissue Sample Preparation and Measurement Proceduressupporting

confidence: 55%

Section: Tissue Dielectric Properties: Background and Relevant Wormentioning

confidence: 99%

Open-Ended Coaxial Probe Technique for Dielectric Measurement of Biological Tissues: Challenges and Common Practices

et al. 2018

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“…Furthermore, the heating protocol was repeated with an additional two fiber optic temperature sensors positioned in tissue at distances 2 and 3 mm away from the dielectric measurement probe. These measurements were conducted to assess the variation in temperature within the sensing volume of the dielectric probe . Figure illustrates the experimental setup.…”

Section: Methodsmentioning

confidence: 99%

“…These measurements were conducted to assess the variation in temperature within the sensing volume of the dielectric probe. [28][29][30][31][32] Figure 2 illustrates the experimental setup.…”

Section: B Dielectric Property Measurementmentioning

confidence: 99%

Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

2019

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Purpose Computational models of microwave tissue ablation are widely used to guide the development of ablation devices, and are increasingly being used for the development of treatment planning and monitoring platforms. Knowledge of temperature‐dependent dielectric properties of lung tissue is essential for accurate modeling of microwave ablation (MWA) of the lung. Methods We employed the open‐ended coaxial probe method, coupled with a custom tissue heating apparatus, to measure dielectric properties of ex vivo porcine and bovine lung tissue at temperatures ranging between 31 and 150 ∘C, over the frequency range 500 MHz to 6 GHz. Furthermore, we employed numerical optimization techniques to provide parametric models for characterizing the broadband temperature‐dependent dielectric properties of tissue, and their variability across tissue samples, suitable for use in computational models of microwave tissue ablation. Results Rapid decreases in both relative permittivity and effective conductivity were observed in the temperature range from 94 to 108 ∘C. Over the measured frequency range, both relative permittivity and effective conductivity were suitably modeled by piecewise linear functions [root mean square error (RMSE) = 1.0952 for permittivity and 0.0650 S/m for conductivity]. Detailed characterization of the variability in lung tissue properties was provided to enable uncertainty quantification of models of MWA. Conclusions The reported dielectric properties of lung tissue, and parametric models which also capture their distribution, will aid the development of computational models of microwave lung ablation.

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“…For 3.58 mm diameter probe has 1.25-1.5 mm, 2.25 mm, 2.5-3.0 mm sensing depths for ethanol, methanol, water, respectively. In [11], it has been aimed to minimize uncertainties in the dielectric measurement due to the longitudinal heterogeneities by analyzing correspondence between size of tissue in a specimen and effect of that tissue to dielectric properties measurement. In the experiment, 2.2 mm diameter slim form probe from Keysight Technologies (Santa Rosa, CA) has been utilized to measure dielectric properties of samples, which were deionized water, physiological (0.9%) saline, acrylic, a rubberbased tissue-mimicking phantom, porcine muscle, porcine fat, and duck fat.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity and Sensing Depth Analysis of Open-ended Contact Probes for Cancer Diagnosis

Aydınalp

Joof

Akduman

et al. 2019

2019 PhotonIcs &Amp; Electromagnetics Research Symposium - Spring (PIERS-Spring)

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Open-ended contact probes have been widely utilized in laboratory environment to quantify the dielectric properties of high permittivity and lossy materials such as biological tissues and other lossy liquids. At microwave frequencies, the dielectric properties of biological tissues have been quantified with open-ended contact probes method with the motivation of building microwave diagnostic and therapeutic technologies. The method is preferred to other microwave dielectric property measurement techniques due to broadband measurement capabilities and minimal sample preparation requirements. However, the measurement procedure is cumbersome and the measurements tend to be error-prone. The commercial probes can have error rates as high as 5% and it can increase with the cable movements, calibration degradation, and probe wear-off. Although the technique is powerful and able to measure the inherent dielectric property discrepancy between different tissues the applications are confined to laboratory use. To explore the true potential of this technique and enable the transition of this technique to a diagnostic technology, there is a need to improve the technique and analyze the performance in a layered heterogeneous medium. In this work, we performed simulations and measurements with open-ended contact probes having different aperture diameters. The probes are built with copper and Teflon sandwiched between inner and outer conductors. Measurements with openended coaxial probes are performed on layered medium emulating the dielectric properties of the biological tissues to analyze the sensing depth and sensitivity of four in-house fabricated openended coaxial probes. An in-house algorithm is utilized to retrieve the dielectric properties of the mediums utilized during this study.

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Modeling of the dielectric properties of biological tissues within the histology region

Cited by 26 publications

References 26 publications

Open-Ended Coaxial Probe Technique for Dielectric Measurement of Biological Tissues: Challenges and Common Practices

Open-Ended Coaxial Probe Technique for Dielectric Measurement of Biological Tissues: Challenges and Common Practices

Broadband lung dielectric properties over the ablative temperature range: Experimental measurements and parametric models

Sensitivity and Sensing Depth Analysis of Open-ended Contact Probes for Cancer Diagnosis

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