Towards Optimization of Open Ended Contact Probes for Breast Cancer Diagnosis (original) (raw)
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Sensors, 2020
Dielectric characterization of biological tissues has become a fundamental aspect of the design of medical treatments based on electromagnetic energy delivery and their pre-treatment planning. Among several measuring techniques proposed in the literature, broadband and minimally-invasive open-ended probe measurements are best-suited for biological tissues. However, several challenges related to measurement accuracy arise when dealing with biological tissues in both ex vivo and in vivo scenarios such as very constrained set-ups in terms of limited sample size and probe positioning. By means of the Finite Integration Technique in the CST Studio Suite® software, the numerical accuracy of the reconstruction of the complex permittivity of a high water-content tissue such as liver and a low water-content tissue such as fat is evaluated for different sample dimensions, different location of the probe, and considering the influence of the background environment. It is found that for high wa...
Modified open-ended dielectric probe in distinction between cancer and healthy breast tissues
Journal of Non-Crystalline Solids, 2010
A new technique for intra-operative breast cancer tissue recognition is proposed. Using the open-ended probe covered by Mylar Ò film we investigated dielectric properties of breast tissue samples coming from 131 patients. The high efficiency in differentiation between normal and anomalous tissue and the ability to fulfil aseptic conditions is promising in cancer diagnostics. Presence of blood and electrolytes does not disturb measurements. A prototype of intra-operative cancer probe was designed and tested.
Comparison of different methods for dielectric properties measurements in liquid sample media
International Journal of Rf and Microwave Computer-aided Engineering, 2017
Nondestructive techniques to measure dielectric properties of aqueous samples have become a crucial research topic for their impact on emerging biomedical applications. Accurate modeling of the dielectric behavior of biological tissues is fundamental to properly assess biomedical microwave imaging techniques. But it is also highly demanded to enable more reliable pretreatment planning for therapeutic technologies using electromagnetic fields such as hyperthermia and thermal ablation. This paper compares 2 well-documented measuring methods based on open-ended coaxial probe with a broadly commercialized setup and existing literature. Measurements were carried out across the frequency range 0.5-4.5 GHz at 208C on deionized water, methanol, and 2-propanol samples. This selection of media under test is justified by their stability and existing literature on them. Moreover, their permittivity values well cover the variability range in biological tissues. This comparative study shows that the Stuchly and Stuchly method calibrated using deionized water, methanol, and open circuit conditions is a valid alternative to the commercial setups available.
A Transmission-Based Dielectric Property Probe for Clinical Applications
Sensors
We have developed a transmission-based, open-ended coaxial dielectric probe that can be used in clinical situations and overcomes many of the limitations related to the typical reflection-based dielectric probes. The approach utilizes the low profile, open-ended coaxial cables enabling clinicians to still probe relatively compact spaces. The sensing depth can be extended to as large as 1.5 to 2 cm compared with the more typical range of 0.3 mm for conventional probes and is dramatically less affected by measurement technique variability including poor sample contact and cable bending. As a precursor to an actual clinical implementation, we study the technique in a range of homogeneous liquids with substantially varying dielectric properties. The initial results demonstrate good agreement between the transmission-based probe and commercial, reflection-based probes and pave the way for more substantial clinical implementation.
ANA Calibration Method for Measurements of Dielectric Properties
IEEE Transactions on Instrumentation and Measurement, 2000
Routine network analyzer calibration procedures in measurements of the dielectric properties of materials using an open-ended coaxial line probe are frequently inadequate and limit the accuracy of measurements. A calibration method, which makes use of liquids whose properties are well known, is proposed to alleviate this limitation. It is shown that even one liquid used as a standard in place of a matched load greatly improves the accuracy of measurements. Theoretical relationships and experimental results as well as some practical suggestions related to the application of this method are given.
Determination of dielectric permittivity of materials by an isolated coaxial probe
2007
The paper investigates the possibility of measuring complex dielectric permittivity of various media by a probe in the form of open-ended coaxial line isolated from the medium probed by a thin dielectric layer. Suitable-for-calculations full-wave admittance model of such probe has been developed in the form of a series with the number of terms corresponding to the number of higher modes excited in its aperture. The presented numerical estimates indicate that despite a certain loss of sensitivity as compared with the conventional technique, this isolated probe can have an application due to a higher stability of its parameters.
Data acquisition with Coaxial Dielectric Probes
2019
This document's intention is to provide a generic and instrument-unspecific guideline to help in the process of acquiring reliable and reproducible data with a coaxial dielectric probe. Areas covered are sample and coaxial probe handling, data storage and a few quick reminders on data analysis. Extensive advice on data analysis is beyond the document's scope.
Assesment of accurate dielectric model and selected patents on microwave breast cancer detection
2015
Advances in microwave breast cancer detection and imaging during last decade are reported in this review paper. An introduction to breast cancer and detection methods and detailed information about microwave imaging and selected patents are presented. The advantages and disadvantages of the presented patents and also state of breast cancer detection and imaging are discussed. Microwave imaging for breast tumor detection is considered to be promising, as it is believed that there is a significant or detectable contrast in malignant, benign and normal tissues over a broad frequency range. Also, there have been many dielectric models, especially the double Debye model has been used to define the dielectric response of different biological tissues. On the other hand, double Debye model is not accurate for human breast tissue because there are knowledge limitations about the structure, dynamics, and macroscopic behavior of breast tissue. It is vital that, according to frequency, accurate...
A versatile measurement system for the determination of dielectric parameters of various materials
Measurement Science and Technology, 2007
In this paper, a versatile method for the determination of the complex permittivity of materials from measured scattering parameters is presented. The measurement setup consists of a waveguide applicator for housing the material sample. The considered frequency range is 2-3 GHz. The complex scattering parameters are measured by a vector network analyser. The algorithm for computing the complex permittivity from the measured scattering parameters is shown in detail and an error estimation is performed. Depending on the waveguide layout liquid, granular and solid materials can be measured. To measure granular and liquid samples two dielectric walls inside the waveguide are used to house the samples. The dielectric parameters of different soils as well as of some liquids are determined with consideration of their moisture content and temperature. In contrast to several other techniques, this measurement setup is also suited for high loss materials. The setup has also been successfully used for measurements of anisotropic materials.