Masters (or Honours) Medical Physics Research Projects for 2015

For more information or to get in touch with supervisors contact Mike House

Title / CT Image Quality and Interpretability in the Lungs
Key Focus Area / Radiology
Supervisors / Prof. Stephen Stick (TKI/PMH), Tim Rosenow (TKI)
Project Type / Analytical/Experimental
Project Outline / Cystic fibrosis (CF) is the most common life-shortening genetic disease in Australia. In CF, chronic lung disease is the most severe and important result of this genetic defect, causing the majority of morbidity and mortality. This lung disease begins at birth and progresses throughout life, eventually leading to respiratory failure. Currently CT scans are the most sensitive measure of lung disease, and often the only respiratory abnormality detectable in infants and young children. However, each practice does their own thing with radiation dose and image quality, so the beginnings of some kind of standardisation are an important step in reducing radiation dose across the world. This project will look at the effect of CT dose and other imaging parameters on image interpretability, particularly in the lungs. Using a large set of human chest CT scans with a range of abnormalities and disease severity, the aim of the project will be to develop a model of noise in CT images of the lungs introduced by variable dose and CT settings. The model could then be used to systematically introduce noise to CT images and look at the interpretability of the image, both with numerical metrics and subjectively with the input of a radiologist.
Title / Linear accelerator shielding - impact of long-term irradiation
Key Focus Area / Radiation Safety
Supervisors / A/Prof. Martin Ebert (SCGH), A/Prof. Michael House (UWA)
Project Type / Experimental/Analytical
Project Outline / Bunkers housing linear accelerators at the Sir Charles Gairdner Hospital (SCGH) have been in use for approximately 40 years. The incident high-energy photons and neutrons will have induced transformations in many nuclei in the shielding materials. These bunkers are being vacated and we have an opportunity to examine these transformations, which may have implications for the design of future facilities. Samples of materials, including wall plaster, fittings and concrete core samples, will be obtained from sections of bunkers that have received sustained irradiation. The elemental and isotopic composition of the materials will be determined by mass spectrometry (and possibly ion probe imaging). For surface materials, these will be compared with samples from non-irradiated regions of the hospital that were installed at a similar time. For core concrete samples, the profile of composition with depth in the wall will be related to the expected attenuation of radiation with depth in the material. Any measured changes in composition will be examined relative to the useage history of the bunker, the spectra of radiation used during that time and the interaction cross-sections for radiation with particular nuclei.
Title / 3D Dosimetry for Complex Radiotherapy Plans
Key Focus Area / Radiology/ Radiotherapy
Supervisors / A/Prof. Michael House (UWA), A/Prof. Pejman Rowshan Farzad (UWA)
Project Type / Experimental/Analytical
Project Outline / 3-D radiation dosimetry is an important technique for measuring the complex dose distribution that arises from modern radiotherapy treatments like the Cyber Knife. However, our ability to measure complex doses routinely in the patient setting requires improvement and refinement. Experimental approaches to measuring dose distributions are necessary to validate the widely used computational simulations based on Monte Carlo simulations. The aim of this research project is to develop a suitable gel phantom for radiotherapy dosimetry and image the phantom using a variety of quantitative MRI approaches to map the 3-D dose distribution. The project will determine the accuracy of image-based dosimetry through comparison against simulated dose distributions and conventional dose measurements (film, ion chamber, TLD, solid state devices). These experiments should help to improve the utility of imaging to map complex dose distributions in the clinical setting.
Title / Radiotherapy enhancement with gold nanoparticles
Key Focus Area / Radiotherapy
Supervisors / A/Prof. Martin Ebert (SCGH), A/Prof. Pejman Rowshan Farzad (UWA), A/Prof. Michael House (UWA)
Project Type / Experimental/Analytical
Project Outline / Gold nanoparticles have been shown to increase the radiosenstivity of cancer cells by providing a greater interaction cross section for the photon and the production of short-range electrons which lead to an increase in DNA damage. To safely and effectively use gold nanoparticles, we need to investigate and quantify the enhanced impact of radiation caused by them. This project will involve the development and characterisation of gold nanoparticles, cell culture experiments to show possible evidence of any revival and to validate that the tumour cells have been destroyed, radiobiological modelling to link nanoparticle characteristics, energy deposition and biological response and Monte Carlo modelling of x-ray interaction with gold nanoparticles. Through these experiments we hope to gain a better understanding of how gold nanoparticles can be optimised for clinical radiotherapy.
Title / Human-analogous radiotherapy treatment planning on a small-animal treatment unit
Key Focus Area / Radiotherapy/Radiology
Supervisors / Prof Martin Ebert (SCGH)
Project Type / Analytical/computational
Project Outline / Human radiotherapy involves the precise (mm-scale) delivery of radiation beams with complex configurations, and the resulting dose distributions can be matched to spatial variations in anatomy and organ function. In preclinical studies, devices capable of mimicking human radiotherapy are available, with one such device being installed at the Telethon Kids Institute in late 2015 (TBC). This project will involve investigating the range of irradiation techniques, capabilities for dose manipulation and level of analogy with human irradiation that can be achieved with this system. With early access to the associated computerised planning system and a sample mouse image set, the capabilities of irradiation will be assessed across the range of available irradiation methods. Assessment will be made of the dose statistics that can be derived from the resulting plans, and an investigation will be made of uncertainties in the underlying dose metrics.
Title / Radiotherapy treatment planning based on voxel-level probabilities
Key Focus Area / Radiotherapy
Supervisors / Prof Martin Ebert (SCGH)
Project Type / Theoretical/analytical/computational
Project Outline / Radiotherapy treatment planning is currently based on a volumetric model of human anatomy; organs and targets to be treated are considered as 3D (maybe 4D) structures extending over many millimetres. This limits the way that information can be incorporated into the treatment planning process. Such information could include functional imaging and spatio-temporal variation in sensitising agents and adjuvant therapy agents, statistical models of response based on the outcomes of previous patients and the data used to inform treatment, and biological response mechanisms that incorporate spatial and temporal cross-correlation. This project will involve building mathematical models that can incorporate complex, probabilistic information on treatment and response, into the planning process and methods for using that information to drive patient treatment planning. Experimental data will be available for treatment of prostate cancer that will form the basis of a test set for the developed methods.
Title / Combined ferromagnetic/high-Z nanoparticles for image-guided radiotherapy dose enhancement
Key Focus Area / Radiotherapy/Radiology
Supervisors / Prof Martin Ebert (SCGH), A/Prof Mike House (UWA)
Project Type / Computational
Project Outline / Gold nanoparticles have been shown to increase the radiosenstivity of cancer cells by providing a greater interaction cross section for the photon and the production of short-range electrons which lead to an increase in DNA damage. Ideally, we would be able to image the distribution of such nanoparticles in a patient at treatment, in order to ensure the tumour is adequately covered and that the nanoparticles are not concentrating within sensitive healthy tissues. If a ferromagnetic material could be combined with a high-Z material into a nanoparticle, we could achieve both of these aims. This project will involve simulating hypothetical combined-material nanoparticles with the Monte Carlo package Geant4. Initially, a pure gold nanoparticle will be simulated, followed by various combinations of iron (e.g., mixture, gold shell, side-by-side) in order to observe the impact on generated secondary electron yields.
Title / Spatial mapping of dose, treatment toxicity and treatment success in radiotherapy
Key Focus Area / Radiotherapy
Supervisors / Prof Martin Ebert (SCGH)
Project Type / Analytical/computational
Project Outline / When a patient is treated in radiotherapy, radiation dose is delivered to a ‘target’. This target is meant to represent the tissue to be treated, but may not. To get the dose to the target, it is also necessary to deliver some dose outside of the target. In this project, real data from a clinical trial will be used to map changes in radiation dose throughout a patient anatomy to the likelihood of the success of dosing the real tissue to be treated, and the likelihood of causing damage (‘toxicity’) to tissues outside of the real target. This will involve taking co-registered patient datasets, developing algorithms for combining their dose distributions and statistically mapping that dose to treatment success or toxicity.
Title / Spatial dose-response in kidney
Key Focus Area / Radiotherapy/nuclear medicine
Supervisors / Prof Martin Ebert (SCGH), A/Prof Mike House (UWA)
Project Type / Analytical/computational
Project Outline / When using radiotherapy to treat patients with abdominal cancers, the kidneys typically receive some radiation dose. The pattern of dose across the kidneys can influence any damage caused to them, with the spatial distribution of kidney function impacting on that dose-response. We have functional image data (SPECT) for a number of patients treated for abdominal cancers that will allow us to investigate that spatial dose-response relationship. This project will involve taking co-registered radiotherapy dose and SPECT function information and examining the relationships between dose and function, with the aim of developing a model of spatial dose-function response in kidney.

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