Conception of a Tissue Equivalent Plastic Dosimeter Using Scintillating Fibres for Hadronic Therapy and Space Radiation Effects Studies

• Autor(a) principal: Carvalho, Filipa Duque Fragoso de Almeida
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/89188
• topic: Dosimetry; Scintillating Fibers; Detectors; Radiotherapy; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Radiotherapy, and more specifically, proton therapy, presents a state-of-the-art treatment for many types of cancer. Although this relatively new approach to cancer treatment is enticing, it needs to be carefully monitored as it can result in unwanted severe sideeffects. The control of the treatment depends on test phases, namely to determine the dose to be deposited at the site, as well as on equipment that monitors the particle beam during treatment, a beam profile monitor, which verifies the stability of the intensity and position of the beam, its range and its straggling effect. This work proposes using scintillating fibres in the assembly of an equipment that allows measurements both for dose determination, as well as for beam monitor profile aplications. Plastic fibres in dosimetry present many advantages such as that gas is not required, the scintillation decay time is typically on the order of a few nanoseconds, the tissue equivalent characteristics of plastic, the spatial granularity is proportional to the fibre diameter and the signal amplitude is proportional to the deposited energy in the fibres. Though this linearity does not happen near the Bragg peak due to quenching, a typical effect in scintillating materials. Another issue is the crosstalk effect between adjacent fibres. Therefore this work is the beginning of a characterization study to learn about the fibre’s properties and evaluate their use in detectors for hadronic therapy and space effects studies. Given the complexity of the problem few results were obtained, nevertheless several iteration of Monte Carlo simulations are performed, we successfully measure the attenuation coefficient of the fibres as we also create a tray in order to quantify the crosstalk effect between adjacent fibres.