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Review
. 2018 Jun 5;8(2):40.
doi: 10.3390/diagnostics8020040.

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

Alessandra La Gioia  1 , Emily Porter  2 , Ilja Merunka  3 , Atif Shahzad  4 , Saqib Salahuddin  5 , Marggie Jones  6 , Martin O'Halloran  7
Affiliations
Review

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

Alessandra La Gioia et al. Diagnostics (Basel). .

Abstract

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.

Keywords: biological tissues; dielectric measurements; equipment-related confounders; open-ended coaxial probe; tissue-related confounders.

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Conflict of interest statement

The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

Figures

Figure 1
Figure 1
Open-ended coaxial probe technique: (a) Schematised measurement set-up, including the Vector Network Analyser (on the right), the cable connecting one port of the VNA to the coaxial probe, the probe bracket, and the liquid sample being measured; (b) top and side cross-sections of the coaxial probe, with electric field orientation indicated.
Figure 2
Figure 2
Flow chart of the common steps to minimise tissue-related errors in in vivo and ex vivo measurements.
Figure 3
Figure 3
Diagram of sample composition by tissue type (fat—orange, gland—blue). A side view of the sample is shown, with slices marked. The dielectric probe measurement location is denoted with a black oval on the top of Slice 1.
See this image and copyright information in PMC

References

    1. Formica D., Silvestri S. Biological Effects of Exposure to Magnetic Resonance Imaging: An Overview. Biomed. Eng. Online. 2004;3:11. doi: 10.1186/1475-925X-3-11. - DOI - PMC - PubMed
    1. Martellosio A., Pasian M., Bozzi M., Perregrini L., Mazzanti A. Exposure Limits and Dielectric Contrast for Breast Cancer Tissues: Experimental Results up to 50 GHz; Proceedings of the 11th European Conference on Antennas and Propagation (EUCAP); Paris, France. 19–24 March 2017; pp. 667–671.
    1. Nikolova N.K. Microwave Imaging for Breast Cancer. IEEE Microw. Mag. 2011;12:78–94. doi: 10.1109/MMM.2011.942702. - DOI
    1. Pastorino M. Microwave Imaging. John Wiley & Sons; Hoboken, NJ, USA: 2010.
    1. Noghanian S. Introduction to Microwave Imaging. Springer; New York, NY, USA: 2014.