- Title
- Magnetic Resonance Imaging (MRI) only radiation therapy treatment planning for complex pelvic cancers
- Creator
- O'Connor, Laura
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2023
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Radiation oncology has a history of utilising advanced technology to improve the accuracy and efficiency of radiation treatments. As treatment techniques in radiation oncology progress, the need for greater visualisation of treatment and normal tissue structures is increased. Due to the improved tissue contrast and functional imaging capabilities, Magnetic Resonance Imaging (MRI) is becoming an increasingly favoured imaging modality, aiding in the advancement of radiation therapy treatments. MRI provides a greater visualisation of soft tissue targets and organs at risk (OAR) structures, as well as providing biological information on the target structures, far beyond what conventional computed tomography (CT) affords in radiation therapy treatment planning. An MRI-only workflow would be beneficial in the radiation therapy treatment planning process to reduce the errors associated with a multi-modal workflow. A major hurdle to the implementation of MRI in radiation therapy treatment planning, is the requirement for electron density and mass density attenuation information for dose calculation by the radiation therapy planning software. The grey scale units of the CT scan directly relate to the electron and mass density of the tissues, while the grey scale units of the MRI relate to the magnetic properties of the tissues. Therefore, in order to supersede the current application of CT and to utilise MRI solely for radiation therapy treatment planning, the electron density and mass density values of the tissues need to be estimated from the MRI scan. This process involves creating a synthetic CT (sCT) scan from the MRI scan, for treatment dose calculations. This thesis aimed to extend the application of previously successful sCT generation techniques, by applying to a wider pelvic treatment population, and a male and female cohort to accommodate MRI-only planning for a greater number of patients and treatment sites in the pelvic region. sCT generation methods applied to the same cohort of patients and assessed for dosimetric and anatomical accuracy. The work also aimed to apply a commercially available model of sCT generation for analysis, and to improve the dosimetric results using a derived density curve. This thesis extended the image guidance considerations for this cohort of patients, to validate the use of MRI for treatment image guidance. Collectively this body of work investigates the application of sCT creation for MRI only treatment planning for cancers of the pelvic region. This thesis addresses the research gaps of current studies which are limited to specific tumour regions, small cohort sizes, omission of the female population and provides a direct comparison of sCT techniques on the same population. This body of work builds on this MRI only planning concept to also address the use of the planning scan for daily treatment guidance.
- Subject
- radiation therapy; Magnetic Resonance Imaging; synthetic computed tomography; computer-assisted radiotherapy planning; image guided radiotherapy
- Identifier
- http://hdl.handle.net/1959.13/1514267
- Identifier
- uon:56837
- Rights
- Copyright 2023 Laura O'Connor
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 26 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 983 KB | Adobe Acrobat PDF | View Details Download |