Radiotherapy is a therapeutic modality that uses ionizing radiation to cause biological damage. High Intensity Focused Ultrasound (HIFU) is a therapeu

1) Brief description of the context of the research including potential impact

Radiotherapy is a therapeutic modality that uses ionizing radiation to cause biological damage. High Intensity Focused Ultrasound is a therapeutic modality that uses ultrasound to induce heat to cause biological damage. These two modalities have complementary qualities. Radiotherapy can cover large volumes and deliver treatment quickly, but it cannot be intensely focused in a region without irradiating healthy tissues. HIFU treats smaller volumes, typically of the size of a grain of rice, with little to no harm to the normal tissues. The combination of both modalities allows one to supplement the other. HIFU can be used to focus on radioresitant regions while radiotherapy is used to cover surrounding volumes which require less radiological dose. This development will require the ability to perform dosimetry and Quality Assurance measurements. Tissue mimicking materials are non-human materials that are manufactured to resemble some aspects of human's tissues properties. A single material is unlikely to perfectly match all physical properties, but it would match a range of them under certain conditions. Phantoms are tissue surrogates used in a variety of metrologic assessments. The result of this research will also be useable for both modalities independently which is of interest for ultrasound modalities, since there are less standardized procedures compared to radiological modalities.

2) Aims and Objectives

Identify materials that are suited for both radiotherapeutic and ultrasonic exposures. These materials must be long lasting and/or easily reproducible. It is preferable if these materials are easy to handle, safe and cheap. It would be ideal if these materials had properties identical to those of human tissues. As measurements done in them would directly translate into a clinical context. Characterize those materials in terms of their physical properties as well as their usability for the manufacturing processes and shelf life. Identify methods that can be used to characterize and parametrize exposures for metrology that are compatible with the materials and other machinery that is involved in exposures and diagnostics, such as MR imaging. Design and develop a phantom that allows to perform QA or dosimetry measurements

3) Novelty of Research Methodology

Firstly, the development of phantoms and TMMs in both modalities has been carried out independently. While hydrogels have been used in radiotherapy, they were intended to have their density changed by the exposure as a measure of dose, which would make them unusable for ultrasonic propagation. Secondly, the study of the effects of irradiation of gels has typically been focused around its use in the gelation process and mechanical properties while not much attention has been paid to acoustic properties and their stability after irradiation. In the case of ultrasound exposures, the evaluation of the therapy is typically the examination of the patient after or during treatment rather than a priori assessments.

4) Alignment to EPSRC's strategies and research areas.

This project represents a combination of two areas of expertise that are similar but have not commonly intersected that have a shared goal. The field of combined Radiotherapy and HIFU is a growing one, as more research shines a light on the benefits of such treatments. This is also a project that focuses strongly in manufacturing and the creation of a product that will positively impact the standard of care that medical industries can provide.

5) Any companies or collaborators involved

This project is being carried out in a collaboration between the University College London, the Institute of Cancer Research and the National Physical Laboratory.