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Master's Dissertation
DOI
10.11606/D.18.2017.tde-30102017-084906
Document
Author
Full name
Ricardo Toshiyuki Irita
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1999
Supervisor
Committee
Slaets, Annie France Frère (President)
Moraes, José Carlos Teixeira de Barros
Moura Junior, Lincoln de Assis
Title in Portuguese
Estudo e simulação de métodos de colimação para melhoria de nitidez da imagem mamográfica
Keywords in Portuguese
Colimador
Imagem médica
Mamógrafo
Simulação de métodos
Abstract in Portuguese
Neste trabalho estamos propondo diminuir o tamanho do ponto focal usando um colimador externo ao aparelho, no lado do catodo, mascarando assim, parte do ponto focal. Esta localização permite utilizar a região onde há maior intensidade de radiação por efeito "heel". Este método tem também a vantagem de diminuir o efeito Compton. As localizações do colimador foram encontradas por simulação computacional de acordo com o seguinte compromisso: maior faixa do filme com ponto focal reduzido sem comprometer a intensidade do feixe de radiação. A simulação computacional foi programada em linguagem pascal (Delphi) considerando que o ponto focal possui forma e distribuição de intensidade variadas. Os parâmetros para a simulação foram utilizados para a realização de um dispositivo experimental. As imagens obtidas com este dispositivo foram comparadas às imagens simuladas afim de comprovar a validade do modelo.
Title in English
not available
Keywords in English
not available
Abstract in English
Throughout this work we intend to decrease the focal spot size putting an extemal collimator on the side of the cathode beneath the mammography device, this concealing part of the focal spot. This setting permits the use of the area where there is more radiation intensity by "heel" effect. This method has the advantage of decreasing the Compton effect too. The setting of the collimator were determined by computer simulation in the accordance in the following commitment: a larger band of the film and reduced focal spot size. These settings were determined without committing the radiation beam intensity. The computer simulation was programmed using pascal (Delphi) taking in a count that the focal spot has varied intensity distribution and geometry. The parameters applied for the simulation were used for the accomplishment of an experimental device. The images obtained with this device were compared to the simulate images so as to prove the validity of the model.
 
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Publishing Date
2017-10-30
 
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