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SPECT Imaging With Resolution Recovery

IEEE TRANSACTIONS ON NUCLEAR SCIENCE 2012年第4期59卷 1458-1464页

作者： bronnikov, Andrei V. Bronnikov Algorithms NL-6800 AB Arnhem Netherlands

Single-photon emission computed tomography (SPECT) is a method of choice for imaging spatial distributions of radioisotopes. Applications of this method are found in medicine, biomedical research and nuclear industry. This paper deals with improving spatial resolution in SPECT by applying correction for the point-spread function (PSF) in the reconstruction algorithm and optimizing the collimator. Several approaches are considered: the use of a depth-dependent PSF model for a parallel-beam collimator derived from experimental data, the extension of this model to a fan-beam collimator, a triangular approximation of the PSF for reconstruction acceleration, and a method for optimal fan-beam collimator design. An unmatched projector/backprojector ordered subsets expectation maximization (OSEM) algorithm is used for image reconstruction. Experimental results with simulated and physical phantom data of a micro-SPECT system show a significant improvement of spatial resolution with the proposed methods.

关键词： Image quality nuclear medicine single photon emission computed tomography (SPECT)

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SPECT attenuation correction based on combined transmission-emission reconstruction of the attenuation map

SPECT attenuation correction based on combined transmission-...

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2004 Nuclear Science Symposium, Medical Imaging Conference, Symposium on Nuclear Power Systems and the 14th International Workshop on Room Temperature Semiconductor X- and Gamma- Ray Detectors

作者： bronnikov, Andrei V. Bronnikov Algorithms Arnhem Netherlands

Attenuation correction is one of the most important issues in quantitative SPECT. A current trend in SPECT systems development is to employ transmission scanning for estimation of the attenuation map. An alternative approach is to use emission data for this purpose. Both approaches, however, are not free from drawbacks. Transmission data acquired on a SPECT system often suffer from incompleteness and truncation and may exhibit poor statistical properties, whereas determination of the attenuation map from emission projections may require redundant emission measurements and is sensitive to photon statistics. The key idea of the suggested approach is to combine transmission and emission data in order to extract more information from the measurements and therefore provide a better estimation of the attenuation map. The proposed algorithm is based on constrained optimization of the discrete consistency conditions for the emission data, where the transmission data play the role of linear equality constraints. Application to experimental torso phantom data is discussed. © 2004 IEEE.

关键词： Attenuation

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Phase-contrast CT: Fundamental theorem and fast image reconstruction algorithms - art. no. 63180Q

Phase-contrast CT: Fundamental theorem and fast image recons...

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5th Conference on Developments in X-Ray Tomography

作者： bronnikov, Andrei V. Bronnikov Algorithms NL-6800 AB Arnhem Netherlands

ISBN: (纸本)0819463973

Phase-contrast x-ray computed tomography (CT) is an emerging imaging technique that can be implemented at third generation synchrotron radiation sources or by using a microfocus x-ray tube. Promising experimental results have recently been obtained in material science and biological applications. At the same time, the lack of a mathematical theory comparable to that of conventional absorption-based CT limits the progress in this field. We suggest such a theory and prove a fundamental theorem that plays the same role for phase-contrast CT as the Fourier slice theorem does for absorption-based CT. The fundamental theorem allows us to derive fast image reconstruction algorithms in the form of filtered backprojection (FBP).

关键词： phase contrast micro CT tomographic image reconstruction

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SPECT Imaging With Resolution Recovery

SPECT Imaging With Resolution Recovery

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2nd International Conference on Advancements in Nuclear Instrumentation, Measurement Methods and their Applications

作者： bronnikov, Andrei V. Bronnikov Algorithms NL-6800 AB Arnhem Netherlands

ISBN: (纸本)9781457709258

关键词： Image quality nuclear medicine single photon emission computed tomography (SPECT)

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Nonlinear phase retrieval from single-distance radiograph

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OPTICS EXPRESS 2010年第25期18卷 25771-25785页

作者： Moosmann, Julian Hofmann, Ralf bronnikov, Andrei V. Baumbach, Tilo KIT LAS D-76128 Karlsruhe Germany KIT Inst Synchrotronstrahlung ISS D-76344 Eggenstein Leopoldshafen Germany Bronnikov Algorithms NL-6800 AB Arnhem Netherlands

Phase contrast in the object plane of a phase object is retrieved from intensity contrast at a single object-detector distance. Expanding intensity contrast and phase shift in the detector plane in powers of object-detector distance, phase retrieval is performed beyond the solution to the linearized transport-of-intensity equation. The expansion coefficients are determined by the entire paraxial wave equation. The Laplacian of the phase shift in the object plane thus is written as a local expression linear in the intensity contrast and nonlinear in the phase shift in the object plane. A perturbative approach to this expression is proposed and tested with simulated phantom data. (c) 2010 Optical Society of America

关键词： Interference Interferometry Phase contrast Phase retrieval Phase shift Wavefronts

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SPECT attenuation correction based on combined transmission-emission reconstruction of the attenuation map

SPECT attenuation correction based on combined transmission-...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： A.V. bronnikov Bronnikov Algorithms Arnhem Netherlands

关键词： Image reconstruction Attenuation measurement Single photon emission computed tomography Torso Imaging phantoms Statistics Data mining Constraint optimization Computed tomography Measurement techniques

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SPECT imaging with resolution recovery

SPECT imaging with resolution recovery

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International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA)

作者： Andrei V. bronnikov Bronnikov Algorithms Arnhem Netherlands

Single-photon emission computed tomography (SPECT) is a method of choice for imaging spatial distributions of radioisotopes. Many applications of this method are found in nuclear industry, medicine, and biomedical research. We study mathematical modeling of a micro-SPECT system by using a point-spread function (PSF) and implement an OSEM-based iterative algorithm for image reconstruction with resolution recovery. Unlike other known implementations of the OSEM algorithm, we apply en efficient computation scheme based on a useful approximation of the PSF, which ensures relatively fast computations. The proposed approach can be applied with the data acquired with any type of collimators, including parallel-beam fan-beam, cone-beam and pinhole collimators. Experimental results obtained with a micro SPECT system demonstrate high efficiency of resolution recovery.

关键词： Collimators Image reconstruction Single photon emission computed tomography Mathematical model Phantoms Image resolution Equations

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