La Rosa, V; (2014) Proton-Induced X-ray Emissions from Metal Markers for Range Verification in Eye Proton Therapy. Doctoral thesis , UCL (University College London).

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Abstract

Proton therapy is one of the most advanced modalities for cancer treatments based on radiation, offering finite penetration depth, low energy deposition at the entrance and sharp dose fall-off. However some of its benefits may become a risk for the patient due to the uncertainties during treatment planning and dose delivery. This project investigates the feasibility of implementing a tool for the real time proton beam range verification in order to improve targeting accuracy and help to spare vital organs and healthy tissues as much as possible. The study is addressed to eye proton treatments. Here it is of key importance to obtain a good local control on the tumour while sparing the optical nerve and preserving the functionality of the eye. This involves surgically implanting a metal marker in the back of the eye between the tumour and the optic nerve and detecting the proton induced x-ray emissions (PIXE) generated by a therapeutic proton beam in the target. Preliminary experiments and Monte Carlo modelling were performed in an attempt to identify the parameters that will lead to the design of an ideal system. We focused on reducing the experimental background noise and op- timising the detection limit. PIXE signals were successfully acquired with a Cadmium Telluride (CdTe) detector at the Clatterbridge Cancer Centre (UK) and at the CATANA proton beam line (Italy). It was found that PIXE has a linear dependence with the proton fluence but it is energy dependent. This makes it unfeasible to be used for in vivo dosimetry. The most suitable metal was investigated and the minimum detectable residual range for gold and silver was assessed, even at clinical conditions. Statistical models for the multivariate analysis of the acquired data were implemented and a pos- sible use of PIXE was suggested in combination with the current treatment planning tools, to double check the correctness of a treatment delivery.

Type:	Thesis (Doctoral)
Title:	Proton-Induced X-ray Emissions from Metal Markers for Range Verification in Eye Proton Therapy
Language:	English
Additional information:	Permission for digitisation not received.
Keywords:	Proton therapy, PIXE, Ocular Melanoma, Range verification
UCL classification:	UCL > Provost and Vice Provost Offices 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.ucl.ac.uk/id/eprint/1436761

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