A combined microwave and optical sensor system with application in cancer detection

Estephan, May 2021. A combined microwave and optical sensor system with application in cancer detection. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Cancer remains a significant health problem, despite great scientific advances in recent years. Biomedical imaging procedures are commonly used to facilitate the diagnosis and treatment of different types of cancer. However, there are still many limitations to these diagnostic techniques. To overcome some of these issues, new approaches are urgently needed. This study aims to establish potential new techniques to improve disease staging diagnosis through more accurate detection and allow real-time monitoring of sample characteristics to help the surgeons reduce the number of biopsies for making a diagnosis. An optical probe has been fabricated in our laboratory with specific characteristics resulting from modelling and experimental exploration. This probe produced encouraging results from a tissue phantom with an ability to distinguish between different particle sizes 2, 0.8 and 0.413 μm with various polystyrene spheres in suspension (PS) concentrations. A Microwave cavity resonator showed the ability to distinguish between different saline dilutions for two types of preparation and different PS concentrations with some limitations. Many correction techniques were developed to enhance the quality of the data obtained. A novel T- Structure and capacitive coupling technique enabled a more robust S21 measurement to be made utilising a resonant coaxial probe at microwave frequencies between around 0.1 GHz and 6 GHz. This structure was modelled and used in experimental scenarios leading to the ability to distinguish between various saline dilutions and different concentrations of PS. Additional correction techniques showed a significant improvement in PS detection limits. Some difficulties have been overcome, relating to settling the PS particles in suspension, corrosion of the microwave probe, and signal processing. All of this has led to a novel system design by combined the optical and microwave sensor system to facilitate effective and efficient tumour detection. This novelty demonstrated that this new system could distinguish between different particles sizes by optical detection and dielectric properties by microwave characterisation. The concluding section of this thesis presents the simultaneous detection of PS samples of different concentrations optically and with the microwave probe. This represents the first time such simultaneous measurements have been carried out using a combined probe such as that described here.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	Optical Probe, Elastic light scattering spectroscopy (ELSS), Advance Design System software (ADS), Cavity technique, Resonant coaxial probe, Combined Microwave / Optical spectroscopy
Date of First Compliant Deposit:	24 September 2021
Last Modified:	07 Oct 2022 01:33
URI:	https://orca.cardiff.ac.uk/id/eprint/144439

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