Sensing volume of open-ended coaxial probes for dielectric characterization of breast tissue at microwave frequencies

Abstract

Abstract-We are using open-ended coaxial probes to determine the dielectric properties of freshly excised normal and diseased breast tissue specimens. The considerable variability in size and composition of these specimens predicates the need for determining the minimum surgical specimen size that yields accurate measurements for a given probe diameter. We investigate the sensing volume of 2.2-and 3.58-mm-diameter flange-free coaxial probes for both low-and high-water-content tissue using standard liquids that exhibit dielectric properties similar to breast tissue over the microwave frequency range from 1 to 20 GHz. We also present an innovative graphical technique based on the use of Cole-Cole diagrams to determine the error thresholds in the magnitude and phase of the reflection coefficient, which bound the errors in the measured complex permittivity to an acceptable level. Results from self-consistent experiments and finite-difference time-domain simulations indicate that a tissue specimen with a thickness of 3.0 mm and a transverse dimension of 1.1 cm is the minimum size that yields accurate measurements with the 3.58-mm-diameter probe. For the 2.2-mm-diameter probe, the specimen's thickness and width should be at least 1.5 and 5 mm, respectively. These conclusions are relevant not only to breast tissue characterization, but also more generally to the dielectric characterization of a variety of low-and high-water-content biological tissues.

Meme Kanseri Tespitinde Mikrodalgaların Önemi ve Kanserli/Sağlıklı Meme Dokularının Yapay Zeka Algoritmaları ile Tanımlanabilmesi

“…Hava geçirmeyecek şekilde kapatılmış olması durumu da probun performansın uzun sürdürmesini sağlamıştır. Prob algılama derinliği 1-3mm'dir [10]. Bu durum çok küçük dokuların ölçümlerini garanti etmek açısından önemli olmuştur.…”

“…Bu tekniğin tutarlı performansını garanti etmek için, referans sıvılar kullanarak doğruluğunu onaylamışlardır. Doku üzerinden ölçümün iyi yapılabilmesi için prob seçiminin önemli olduğu görülmektedir [10].…”

“…Bu somut meme ve tümör örneklerinin nasıl yapıldığıyla ilgili ayrıntılı bilgi ilgili çalışmada anlatılmıştır [15]. Ölçümler dielektrik spektroskopi metodu kullanılarak elde edilmiştir [10]. Dielektrik sabiti ve elektriksel iletkenlik ölçümleri, E5071B ENA Series Network Analyzer ve 85070 Dielectric Probe Kit kullanılarak gerçekleştirilmiştir.…”

Uncertainty Analysis of the Rational Function Model Used in the Complex Permittivity Measurement of Biological Tissues Using PMCT Probes Within a Wide Microwave Frequency Band

“…In our work, the PMCT probe [12] is used for calibration and measurement. According to the above-mentioned theoretical principle, the parameters of RFM model for our PMCT probe should be obtained firstly.…”

“…In our work, the percutaneous microwave coagulation therapy (PMCT) probe has been employed in the complex permittivity measurement of biological tissues [11][12][13][14].…”