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Master's Dissertation
DOI
https://doi.org/10.11606/D.59.2021.tde-30092021-144627
Document
Author
Full name
Daniel Rodrigues Balbin
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2021
Supervisor
Committee
Poletti, Martin Eduardo (President)
Hönnicke, Marcelo Gonçalves
Kakuno, Edson Massayuki
Mazzaro, Irineu
Title in Portuguese
Imagens de raios X por contraste de fase usando um feixe polienergético: implementação e estudo de um sistema de aquisição
Keywords in Portuguese
Contraste de atenuação
Contraste de fase
Propagação de raios X na matéria
Raios X
Abstract in Portuguese
Nas imagens tradicionais de raios X, o receptor de imagem é colocado logo após o paciente. O contraste da imagem resulta de variações na atenuação de raios X decorrentes de diferenças em composição, densidade e espessura dos tecidos, bem como das energias dos raios X utilizados para formar a imagem. Quando o receptor é colocado a uma certa distância do paciente, a imagem responde também às mudanças de fase dos raios X ocorridas conforme a radiação o atravessa. São formadas assim, as imagens de contraste de fase de raios X. Neste trabalho foi estudado, implementado e aplicada a técnica de imagens de contraste de fase de raios X utilizando uma fonte de raios X com microfoco (alta coerência espacial), essencialmente polienergética, e detectores digitais odontológicos, ambos compatíveis com as fontes convencionais e detectores utilizados clinicamente. Inicialmente todos esses elementos foram caracterizados e, em seguida, o arranjo experimental foi montado e a influência dos parâmetros geométrico e de irradiação foram avaliadas nas imagens. Finalmente, diversos objetos simuladores (contendo fibras e materiais homogêneos nas suas propriedades de atenuação) e tecidos animais (ósseo, fibrosos, adiposos e mistos) foram analisados com o arranjo. O protótipo implementado mostrou um grande potencial para aplicações biológicas e clínicas, mostrando um aumento expressivo no contraste de materiais biológicos e inorgânicos com características similares de atenuação, em comparação com as imagens tradicionais de raios X usando o mesmo espectro de energia.
Title in English
X-ray phase contrast imaging using a polyenergetic beam: Implementation and study of an acquisition setup
Keywords in English
Microstructures
Phase contrast
Propagation arrangement
X-Rays
Abstract in English
In conventional X-ray imaging contrast the image receptor is placed immediately after the patient. The image contrast results from the variations on the attenuation of X-rays within the patient due to the differences in composition, density and thickness of the tissues, as well as of the X-rays energies emitted from the source. When the receptor is placed in a certain distance from the object, the image also responds to the changes in phase of the X-rays occurred as the radiation penetrate the patient. Thus, X-ray phase contrast images are formed. In this work, the X-ray phase contrast imaging technique was studied, implemented and applied using a microfocus X-ray source (high spatial coher-ence), essentially polyenergetic, and digital dental detectors, both compatible with conventional sources and detectors used clinically. Initially, all these elements were characterized and then the experimental setup was built and the influences on the images of geometric and irradiation parameters were evaluated. Finally, several phantoms (containing fibers and homogeneous materials) and animal tissues (bone, fibrous, adipose and mixed) were analyzed with this prototype system. The implemented prototype system showed great potential for biological and clinical applications, showing a significant increase in the contrast of biological and inorganic materials with similar attenuation characteristics, compared to the traditional X-ray images using the same energy spectrum.
 
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Publishing Date
2021-10-01
 
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