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Modelling and development of tissue-equivalent dosimeters for small field radiotherapy. / Maria Antonietta Piliero

Swansea University Author: Maria Antonietta Piliero

Abstract

A radiotherapy treatment is a clinical treatment which makes use of ionizing radiation to treat cancerous diseases. However, the ionizing radiation interacting within the cells can lead to DNA damage in both the cancerous and normal tissues. Therefore the exact knowledge of the dose delivered to the...

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Published: 2013
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42465
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first_indexed 2018-08-02T18:54:46Z
last_indexed 2019-10-21T16:47:52Z
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spelling 2018-08-29T15:07:02.7385181 v2 42465 2018-08-02 Modelling and development of tissue-equivalent dosimeters for small field radiotherapy. b01e80b0aed174b7f7ef41aa6e3dfeae NULL Maria Antonietta Piliero Maria Antonietta Piliero true true 2018-08-02 A radiotherapy treatment is a clinical treatment which makes use of ionizing radiation to treat cancerous diseases. However, the ionizing radiation interacting within the cells can lead to DNA damage in both the cancerous and normal tissues. Therefore the exact knowledge of the dose delivered to the patient is essential because it greatly affects the effectiveness of the treatment. Dosimetry is usually performed by air ionization chambers however their use in the dosimetry of small photon beams is limited by their large sensitive volume. The ideal detector has a small, water-equivalent sensitive volume but the design of the detector and the presence of the encapsulation materials placed in close proximity to the sensitive volume can cause perturbations to the radiation fluence. The Monte Carlo method is the ideal tool because it allows a detailed investigation of the perturbation effects of each detector component but a Monte Carlo model often requires detailed information of the device which can be difficult to access. In this study, an experimental approach involving the use of CT scans and fluorescence spectroscopy in the measurements of the physical properties of a liquid ion chamber was explored. The performance of eight single crystal CVD diamond detectors in the dosimetry of photon beams was also assessed. One of the drawbacks of diamond detectors is the dose rate dependence. The evaluation of the dose rate dependence using clinical photon beams is controversial because the dose rate can be varied by either changing the source to detector distance or the Pulse Repetition Frequency of the LINAC machine. A simple analytical model of the charge collection dynamics was written in the Matlab code to understand the effects introduced by a pulsed radiation beam. The outcome of this study correlates the PRF dependence with the presence of deeper traps. E-Thesis Nuclear physics and radiation. 31 12 2013 2013-12-31 COLLEGE NANME Swansea University Medical School COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-29T15:07:02.7385181 2018-08-02T16:24:29.3377956 Faculty of Medicine, Health and Life Sciences Swansea University Medical School - Medicine Maria Antonietta Piliero NULL 1 0042465-02082018162456.pdf 10798173.pdf 2018-08-02T16:24:56.6370000 Output 16127255 application/pdf E-Thesis true 2018-08-02T16:24:56.6370000 false
title Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
spellingShingle Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
Maria Antonietta Piliero
title_short Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
title_full Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
title_fullStr Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
title_full_unstemmed Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
title_sort Modelling and development of tissue-equivalent dosimeters for small field radiotherapy.
author_id_str_mv b01e80b0aed174b7f7ef41aa6e3dfeae
author_id_fullname_str_mv b01e80b0aed174b7f7ef41aa6e3dfeae_***_Maria Antonietta Piliero
author Maria Antonietta Piliero
author2 Maria Antonietta Piliero
format E-Thesis
publishDate 2013
institution Swansea University
college_str Faculty of Medicine, Health and Life Sciences
hierarchytype
hierarchy_top_id facultyofmedicinehealthandlifesciences
hierarchy_top_title Faculty of Medicine, Health and Life Sciences
hierarchy_parent_id facultyofmedicinehealthandlifesciences
hierarchy_parent_title Faculty of Medicine, Health and Life Sciences
department_str Swansea University Medical School - Medicine{{{_:::_}}}Faculty of Medicine, Health and Life Sciences{{{_:::_}}}Swansea University Medical School - Medicine
document_store_str 1
active_str 0
description A radiotherapy treatment is a clinical treatment which makes use of ionizing radiation to treat cancerous diseases. However, the ionizing radiation interacting within the cells can lead to DNA damage in both the cancerous and normal tissues. Therefore the exact knowledge of the dose delivered to the patient is essential because it greatly affects the effectiveness of the treatment. Dosimetry is usually performed by air ionization chambers however their use in the dosimetry of small photon beams is limited by their large sensitive volume. The ideal detector has a small, water-equivalent sensitive volume but the design of the detector and the presence of the encapsulation materials placed in close proximity to the sensitive volume can cause perturbations to the radiation fluence. The Monte Carlo method is the ideal tool because it allows a detailed investigation of the perturbation effects of each detector component but a Monte Carlo model often requires detailed information of the device which can be difficult to access. In this study, an experimental approach involving the use of CT scans and fluorescence spectroscopy in the measurements of the physical properties of a liquid ion chamber was explored. The performance of eight single crystal CVD diamond detectors in the dosimetry of photon beams was also assessed. One of the drawbacks of diamond detectors is the dose rate dependence. The evaluation of the dose rate dependence using clinical photon beams is controversial because the dose rate can be varied by either changing the source to detector distance or the Pulse Repetition Frequency of the LINAC machine. A simple analytical model of the charge collection dynamics was written in the Matlab code to understand the effects introduced by a pulsed radiation beam. The outcome of this study correlates the PRF dependence with the presence of deeper traps.
published_date 2013-12-31T03:53:01Z
_version_ 1763752627599835136
score 11.016258

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