27 research outputs found
SART-Type Image Reconstruction from Overlapped Projections
To maximize the time-integrated X-ray flux from multiple X-ray sources and shorten the data acquisition process, a promising way is to allow overlapped projections from multiple sources being simultaneously on without involving the source multiplexing technology. The most challenging task in this configuration is to perform image reconstruction effectively and efficiently from overlapped projections. Inspired by the single-source simultaneous algebraic reconstruction technique (SART), we hereby develop a multisource SART-type reconstruction algorithm regularized by a sparsity-oriented constraint in the soft-threshold filtering framework to reconstruct images from overlapped projections. Our numerical simulation results verify the correctness of the proposed algorithm and demonstrate the advantage of image reconstruction from overlapped projections
Line-Source Based X-Ray Tomography
Current computed tomography (CT) scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisition interval. In reference to the simultaneous algebraic reconstruction technique (SART) algorithm for image reconstruction from projection data generated by an x-ray point source, here we develop a generalized SART algorithm for image reconstruction from projection data generated by an x-ray line source. Our numerical simulation results demonstrate the feasibility of our novel line-source based x-ray CT approach and the proposed generalized SART algorithm
Medical imaging: Foundations and scope
Indexación: Scopus; Radalyc.En la actualidad es innegable la utilidad de las diversas modalidades
de imagenología médica como apoyo clínico tanto en
la generación de diagnósticos de un buen número de enfermedades
como en la planeación de tratamientos tendientes a
proporcionar una alternativa de solución a las personas que,
por una u otra razón, manifiestan algún desequilibrio en su
salud. Entre las modalidades imagenológicas que, frecuentemente,
se utilizan en el ámbito médico se pueden mencionar:
Ultrasonido (US), Resonancia Magnética (MRI), Tomografía
Computarizada sencilla (CT) y multicapa (MSCT), Tomografía
Computarizada por Emisión de Positrones (PET) y Tomografía
Computarizada por Emisión de Fotones simples (SPECT).
En este sentido, este artículo tiene como finalidad presentar
una descripción ordenada, coherente y sistemática de cada
una de las mencionadas modalidades y establecer la vinculación
de la MSCT con situaciones clínicas íntimamente relacionadas
con la anatomía cardiaca y procesos de hipertensión.
La razón por la cual se hace énfasis en la MSCT es debido a
que, por una parte, se cuenta con un número importante de
bases de datos tanto de sujetos fisiológicos como de sujetos
patológicos y, por la otra, que se tiene previsto presentar un
conjunto de técnicas computacionales que serán exploradas
en el desarrollo de futuras investigaciones en el contexto de
aspectos anatómico-cardiológicos que influyen directa o indirectamente
en la aparición, desarrollo y prevalencia de procesos
hipertensivos.Nowdays, several forms of medical imaging are usefulness in
clinical support for both diagnostics diseases generation and
treatment planning designed to provide an alternative solution
to people who, for one or another reason, manifest an
imbalance in your health. Among the imaging modalities that
frequently are used in the medical field may include: Ultrasound
(US), magnetic resonance imaging (MRI), simple computed
tomography (CT) and multilayer computed tomography
(MSCT), CT positron emission tomography (PET) Computed
tomography and single photon emission (SPECT). In this sense,
this article presents an orderly, coherent and systematic
description of these modalities and it establishes relationship
with the MSCT modality and clinical situations closely related
to cardiac anatomy and hypertension processes. The reason
emphasis on MSCT is done is because, on the one hand, we
have a large number of databases both physiological subjects
and pathological subjects and, on the other, we plan to
present a set of computational techniques that will be explored
in future research, in the context of cardiologic anatomical
aspects, with directly or indirectly influence in the emergence,
development and prevalence of hypertensive processes.http://www.redalyc.org/articulo.oa?id=5594990700
Medipix-based Spectral Micro-CT?
Since Hounsfield’s Nobel Prize winning breakthrough decades ago, x-ray CT has been widely applied in the clinical and preclinical applications - producing a huge number of tomographic gray-scale images. However, these images are often insufficient to distinguish crucial differences needed for diagnosis. They have poor soft tissue contrast due to inherent photon-count issues, involving high radiation dose. By physics, the x-ray spectrum is polychromatic, and it is now feasible to obtain multi-energy, spectral, or true-color, CT images. Such spectral images promise powerful new diagnostic information. The emerging Medipix technology promises energy-sensitive, high-resolution, accurate and rapid x-ray detection. In this paper, we will review the recent progress of Medipix-based spectral micro-CT with the emphasis on the results obtained by our team. It includes the state-of-the-art Medipix detector, the system and method of a commercial MARS (Medipix All Resolution System) spectral micro-CT, and the design and color diffusion of a hybrid spectral micro-CT
Extensions of incomplete oblique projections method for solving rank-deficient least-squares problems
The aim of this paper is to extend the applicability of an algorithm for solving inconsistent linear systems to the rank-deficient case, by employing incomplete projections onto the set of solutions of the augmented system Ax-r = b. The extended algorithm converges to the unique minimal norm solution of the least squares solutions. For that purpose, incomplete oblique projections are used, defined by means of matrices that penalize the norm of the residuals. The theoretical properties of the new algorithm are analyzed, and numerical experiences are presented comparing its performance with some well-known projection methods.Facultad de Ciencias ExactasFacultad de Ingenierí
Extensions of incomplete oblique projections method for solving rank-deficient least-squares problems
The aim of this paper is to extend the applicability of an algorithm for solving inconsistent linear systems to the rank-deficient case, by employing incomplete projections onto the set of solutions of the augmented system Ax-r = b. The extended algorithm converges to the unique minimal norm solution of the least squares solutions. For that purpose, incomplete oblique projections are used, defined by means of matrices that penalize the norm of the residuals. The theoretical properties of the new algorithm are analyzed, and numerical experiences are presented comparing its performance with some well-known projection methods.Facultad de Ciencias ExactasFacultad de Ingenierí