Exact reconstruction in 2D dynamic CT: compensation of time-dependent affine deformations.
Phys Med Biol
; 49(11): 2169-82, 2004 Jun 07.
Article
em En
| MEDLINE
| ID: mdl-15250070
ABSTRACT
This work is dedicated to the reduction of reconstruction artefacts due to motion occurring during the acquisition of computerized tomographic projections. This problem has to be solved when imaging moving organs such as the lungs or the heart. The proposed method belongs to the class of motion compensation algorithms, where the model of motion is included in the reconstruction formula. We address two fundamental questions. First what conditions on the deformation are required for the reconstruction of the object from projections acquired sequentially during the deformation, and second how do we reconstruct the object from those projections. Here we answer these questions in the particular case of 2D general time-dependent affine deformations, assuming the motion parameters are known. We treat the problem of admissibility conditions on the deformation in the parallel-beam and fan-beam cases. Then we propose exact reconstruction methods based on rebinning or sequential FBP formulae for each of these geometries and present reconstructed images obtained with the fan-beam algorithm on simulated data.
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Base de dados:
MEDLINE
Assunto principal:
Algoritmos
/
Interpretação de Imagem Radiográfica Assistida por Computador
/
Intensificação de Imagem Radiográfica
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Tomografia Computadorizada por Raios X
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Técnica de Subtração
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Artefatos
/
Movimento
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article