Abstract
In recent years, microwave imaging/sensing and hyperthermia technologies have emerged in the field of diagnostics and therapy. Early-stage breast cancer diagnosis is one of the key application areas for the technology, where intervention at an early stage is essential for successful treatment and preventing progression to incurable secondary breast cancer. Breast cancer is the most common cancers in the UK, and advances in the imaging and treatment seek to address this unmet medical need. Current imaging modalities have limitations associated with cost and accessibility.For diagnosis, this technology involves the application of low power microwaves, utilising contrast between the relative permittivity of tissues to identify pathologies. Antennas placed around the target region transmit and receive signals; the signal scatter is impacted by the dielectric properties of the individual tissue. The use of non-ionising radiation and low relative cost allows the technology to be available to a wider patient base, attempting to address the limitations of MRI and mammograms. However, challenges in the field associated with the heterogeneity of breast tissue and variance between individuals, can have an impact on the scale of the contrast in dielectric properties observed, making tumours more difficult to identify. The contrast in tissue permittivity can therefore be further enhanced through the implementation of nanomaterials. This project focuses initially on the development of nanomaterials suitable for use as contrast agents for microwave imaging/sensing. To achieve this, polymer-coated zinc ferrite nanoparticles were synthesised and assessed for their dielectric properties in model systems including ex vivo and in vivo. In particular, in vivo experiments demonstrated injected polymer-coated zinc ferrite nanoparticles increased the observed dielectric constant in triple-negative breast cancer tumours in a mouse model system.
For therapy, microwave technologies can be applied in tissues either through hyperthermia, which can help anti-cancer drug tumour penetration, or as ablation to destroy malignant tissues. Advances in this area have centred on the development of hyperthermia and ablation antennas, designed to selectively heat targeted tissues. However, concerns remain regarding the heating of deep-seated tumours and unintentional heating of peripheral tissues, causing damage. Nanomaterials can absorb electromagnetic radiation and can enhance the microwave hyperthermic effect. This could allow heating to be applied at lower powers, limiting damage to surrounding tissues. This technology has the potential to be combined with thermosensitive drug release, allowing therapeutic targeting to tumours. This project explored the development of a lab microwave hyperthermia (MWHT) setup suitable for use in vivo. This was achieved using suitable breast tumour mimicking phantoms before progression to in vivo experiments. Microwave responsive PSMA-coated zinc ferrite nanoparticles developed for microwave imaging/sensing were also tested in conjunction with the MWHT antenna, to assess the impact on observed heating profiles. Finally, image-guided thermosensitive liposomes (iTSLs) were tested in conjunction with microwave hyperthermia in vivo, to establish if MWHT is suitable for the targeted release of therapeutics.
| Date of Award | 1 Dec 2023 |
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| Original language | English |
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| Supervisor | Maya Thanou (Supervisor) |