Thesis
On-line dosimetry of very high energy electrons at low to ultra-high dose rates based on fluorescence spectroscopy
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2026
- Thesis identifier
- T17668
- Person Identifier (Local)
- 202078126
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- External beam radiotherapy (EBRT) is a method of cancer treatment which applies external sources of ionising radiation in radiotherapy. At ultra-high dose rates (≥ 40 Gy/s) it has been shown to effectively target cancerous tissue, while sparing healthy tissue. This sparing phenomenon is known as the FLASH effect, and is a rapidly evolving field of study. Ionisation chambers – the gold standard for clinical dosimetry – experience significant uncertainties at FLASH dose rates. Alternative dosimetry methods are available, but most cannot determine doses in real-time. This thesis investigates a novel on-line chemical dosimeter that utilises the reduction of resazurin, in aqueous solution, into highly fluorescent resorufin. The dose is determined by fluorescence spectroscopy using common and inexpensive equipment. The dosimeter has been rigorously tested to establish a comprehensive preparation and handling procedure. Its response to X-ray, γ-ray and very high energy electron (VHEE) irradiation has also been investigated at the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) at the University of Strathclyde, the Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA), and the CERN ´ Linear Electron Accelerator for Research (CLEAR) facility, respectively. The results demonstrate the real-time capabilities of the dosimeter at clinically relevant doses for EBRT using γ-rays and VHEEs. A parallel study has been conducted at CLEAR to investigate the therapeutic benefits of a focused VHEE beam, which concentrates dose in a small volume, thus reducing the entrance and exit doses. In addition, a non-invasive imaging modality was tested. It is based on the detection of 511 keV photons emitted when electrons and positrons annihilate, and shows that detection rate is proportional to dose. This technique also has the potential to be used as an oxygen-sensitive imaging modality which could improve the understanding of the FLASH effect in tissue. These studies present new and promising on-line dosimetry methods suitable for FLASH therapy, which widens the therapeutic window for cancer patients.
- Advisor / supervisor
- Baldacchino, Gérard
- Jaroszynski, D. A. (Dino A.)
- Resource Type
- DOI
- Funder
Relazioni
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PDF of thesis T17668 | 2026-03-27 | Pubblico | Scaricare |