Caracterização dos espectros de raios X de média energia através do método Monte Carlo

• Ano de defesa: 2023
• Autor(a) principal: Contreras, Eder Humberto Aguirre
• Outros Autores: [e-mail]
• Orientador(a): Almeida, Carlos Eduardo Veloso de
• Banca de defesa: Mota, Carla Lemos da Silva , Salata, Camila , Teixeira, Flavia Cristina da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Estado do Rio de Janeiro
• Programa de Pós-Graduação: Programa de Pós-Graduação em Biociências
• Departamento: Centro Biomédico::Instituto de Biologia Roberto Alcantara Gomes
• País: Brasil
• Palavras-chave em Português: Radioterapia; Espectro em energia; Simulação Monte Carlo; Terapia por Raios X; Monte Carlo, Método de
• Palavras-chave em Inglês: Radiotherapy; Energy spectrum; Monte Carlo simulation
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS
• Link de acesso: http://www.bdtd.uerj.br/handle/1/22389

This work characterizes the spectra of two X-ray tubes using the Monte Carlo method, specifically, the PENELOPE code. The Monte Carlo method is found in different areas of the exact sciences, being a common resource in medical physics. This method is essentially simple in its approach, achieving a solution of a macroscopic system through the simulation of its microscopic interactions, representing a modeling of nature through direct simulation of the essential dynamics of the system under study. Two medium-energy X-ray tubes were modeled according to the manufacturer’s specifications, and the simulations were divided into two stages due to the computational time. In the first stage, X-ray spectra were obtained right at the tube exit for four qualities of radiation. In the second stage, photon spectra were recorded after modelling the experimental arrangement to obtain the half-value layers (HVLs). An evaluation of the spectra obtained in the second stage was carried out with the spectra from the SpekCalc software, a program that performs the theoretical calculation of spectra under conditions of good geometry, using the t-student statistical test. Mean energy values along with the first and second half-value layer (HVL) of each energy were determined with the respective differences between them. Different discrepancies were found in most cases, and so it is vitally important to consider each situation independently. Finally, secondary electron energy spectra in the second stage of each quality were presented with their respective mean energies, an important parameter considered in the dose deposition of the different experimental geometries that use such qualities. An estimate of the dose impact on Fricke solution of each type of beam is presented at the end of the work to establish a degree of influence of secondary electrons.