These results suggest that ZnO nanomaterials have the potential to be used in biomedical applications such as breast imaging to improve diagnostic capabilities.

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Detecting changes in the dielectric properties of tissues at microwave frequencies can offer simple and cost effective tools for cancer detection. These changes can be enhanced by the use of nanoparticles (NPs) that are characterised by both increased tumour uptake and high dielectric constant. This paper presents a two-port experimental setup to assess the impact of contrast enhancement on microwave signals. The study focuses on carbon nanotubes, as they have been previously shown to induce high microwave dielectric contrast. We investigate multiwall carbon nanotubes (MWNT) and their -OH functionalised version (MWNT-OH) dispersed in tissue phantoms as contrast enhancing NPs, as well as salt (NaCl) solutions as reference mixtures which can be easily dissolved inside water mixtures and thus induce dielectric contrast changes reliably. MWNT and MWNT-OH are characterised by atomic force microscopy, and their dielectric properties are measured when dispersed in 60% glycerol–water mixtures. Salt concentrations between 10 and 50 mg/mL in 60% glycerol mixtures are also studied as homogeneous samples known to affect the dielectric constant. Contrast enhancement is then evaluated using a simplified two-port microwave system to identify the impact on microwave signals with respect to dielectric contrast. Numerical simulations are also conducted to compare results with the experimental findings. Our results suggest that this approach can be used as a reliable method to screen and assess contrast enhancing materials with regards to a microwave system’s ability to detect their impact on a target.

Clinical imaging modalities provide clinical data with a variety of resolutions, clinical implementation costs, and various levels of complexity when applied and interpreted. Imaging techniques that are aimed at molecular imaging require the utilization of ionizing radiation that can pose safety risks and questions related to their frequent use. Microwave sensing and imaging (MSI) is emerging as an alternative method based on nonionizing electromagnetic (EM) signals that lie over a wide frequency range. The main advantages of using EM signals is the low health risk, low cost of implementation, low operational cost, ease of use, and user friendliness. The development of such systems may revolutionise treatments and contribute to advanced safe and cost effective detection and/or treatments. MSI has been used for tumour detection (breast), blood clot/stroke detection, heart imaging, bone imaging, cancer detection, and localization of in-body radio frequency (RF) ablation sources. The introduction of tailor made agents to enhance microwave (MW) dielectric contrast may provide a very useful clinical tool. In MSI applications, nanomaterials that change the dielectric constant when concentrated in tumours could be an elegant solution for tumour detection. MW devices used for sensing can also induce focused and controlled elevation of temperature in tissues (hyperthermia, ablation). This dual operation of MW devices can be combined with smart temperature responsive drug delivery systems to provide integrated tumour therapy and targeted drug delivery systems. The aim of this chapter is to provide an overview of this emerging technique and its potential in diagnostics and therapy.