An Approach to Identify Circulating Tumor Cell Using Ring Resonator Type of Electrode Using Oscillation Technique at Centimeter Frequency Bands

Futoshi KUROKI  Shouta SORA  Kousei KUMAHARA  

IEICE TRANSACTIONS on Electronics   Vol.E103-C   No.10   pp.411-416
Publication Date: 2020/10/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2020MMI0003
Type of Manuscript: INVITED PAPER (Special Section on Microwave and Millimeter-Wave Technologies)
Category: Microwaves, Millimeter-Waves
circulating tumor cell,  resonant frequency,  ring-resonator,  primary tumor,  oscillator,  

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A ring-resonator type of electrode (RRTE) has been proposed to detect the circulating tumor cell (CTC) for evaluation of the current cancer progression and malignancy in clinical applications. Main emphasis is placed on the identification sensitivity for the lossy materials that can be found in biomedical fields. At first, the possibility of the CTC detection was numerically considered to calculate the resonant frequency of the RRTE catching the CTC, and it was evident that the RRTE with the cell has the resonant frequency inherent in the cell featured by its complex permittivity. To confirm the numerical consideration, the BaTiO3 particle, whose size was similar to that of the CTC, was inserted in the RRTE instead of the CTC as a preliminary experiment. Next, the resonant frequencies of the RRTE with internal organs of the beef cattle such as liver, lung, and kidney were measured for evaluation of the lossy materials such as the CTC, and degraded Q curves were observed because the Q-factors inherent in the internal organs were usually low due to the poor loss tangents. To overcome such difficulty, the RRTE, the oscillator circuit consisting of the FET being added, was proposed to improve the identification sensitivity. Comparing the identification sensitivity of the conventional RRTE, it has been improved because the oscillation frequency spectrum inherent in an internal organ could be easily observed thanks to the oscillation condition with negative resistance. Thus, the validity of the proposed technique has been confirmed.