Cook, Hannah;
(2023)
Development of tools and methodologies for proton dosimetry audit.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
High-energy proton beam therapy (PBT) is an advanced form of radiotherapy which is now being provided by the NHS in the UK. As for any radiotherapy, accurate dosimetry of proton beams is a prerequisite for a successful treatment. A crucial method of quality assurance assessment of the patient treatment is end-to-end dosimetry audits which evaluate the quality of practice of the full treatment. This work contributes to PBT audits, through the development of tools and techniques that increase the accuracy of the determination of absorbed dose. Existing tissue-equivalent materials (TEM) have been shown to be unsuitable for PBT audits. This project developed a cost-function model for the formulations of imaging photon and therapeutic proton optimised TEM. In addition, new materials were successfully manufactured and characterised by experiments and Monte Carlo simulations. These novel materials were shown to be superior to current commercial TEMs. The best novel formulations were shown to mimic stopping power, mass attenuation, and mass density within 2%, along with further reducing the uncertainty in other key radiation properties. This work has also led to the development of two bespoke phantoms that test PBT delivery challenges. The Range Length Phantom studies show film can provide repeatable range measurements within an average relative uncertainty of 0.5% for a series of heterogenous phantom setups within an audit setting. A pilot audit was performed with the PRoton heaD and NeCk Evaluation phantom. The study showed 2% agreement between detectors within the tumour region to treatment planning system predictions. Film analysis showing a >95% pass rate for 4%/3 mm gamma analysis. Overall, the phantom was shown to be a useful tool to evaluate PBT deliveries and provides a realistic challenge for clinical centres as part of an end-toend audit service.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Development of tools and methodologies for proton dosimetry audit |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10179986 |
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