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World Wide Web interface for advanced SPECT reconstruction algorithms implemented on a remote massively parallel computer

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INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS 1997年第1-2期47卷 125-138页

作者： Formiconi, AR Passeri, A Guelfi, MR Masoni, M Pupi, A Meldolesi, U Malfetti, P Calori, L Guidazzoli, A Univ Florence Dept Clin Physiopathol Florence Italy CINECA Bologna Italy

Data from Single Photon Emission Computed Tomography (SPECT) studies are blurred by inevitable physical phenomena occurring during data acquisition. These errors may be compensated by means of reconstruction algorithms which take into account accurate physical models of the data acquisition procedure. Unfortunately, this approach involves high memory requirements as well as a high computational burden which cannot be afforded by the computer systems of SPECT acquisition devices. In this work the possibility of accessing High Performance Computing and Networking (HPCN) resources through a World Wide Web interface for the advanced reconstruction of SPECT data in a clinical environment was investigated. An iterative algorithm with an accurate model of the variable system response was ported on the Multiple Instruction Multiple Data (MIMD) parallel architecture of a Cray T3D massively parallel computer. The system was accessible even from low cost PC-based workstations through standard TCP/IP networking. A speedup Factor of 148 was predicted by the benchmarks run on the Gray T3D. A complete brain study of 30 (64 x 64) slices was reconstructed from a set of 90 (64 x 64) projections with ten iterations of the conjugate gradients algorithm in 9 s which corresponds to an actual speed-up factor of 135. The technique was extended to a more accurate 3D modeling of the system response for a true 3D reconstruction of SPECT data, the reconstruction time of the same data set with this more accurate model was 5 min. This work demonstrates the possibility of exploiting remote HPCN resources from hospital sites by means of low cost workstations using standard communication protocols and an user-friendly WWW interface without particular problems for routine use. (C) 1997 Elsevier Science B.V.

关键词： single photon emission tomography reconstruction algorithms medical images parallel computer high performance computing and technology WWW

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Practical fully three-dimensional reconstruction algorithms for diffuse optical tomography

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 2012年第6期29卷 1017-1026页

作者： Biswas, Samir Kumar Kanhirodan, Rajan Vasu, Ram Mohan Roy, Debasish Indian Inst Sci Dept Instrumentat & Appl Phys Bangalore 560012 Karnataka India Indian Inst Sci Dept Phys Bangalore 560012 Karnataka India Indian Inst Sci Dept Civil Engn Computat Mech Lab Bangalore 560012 Karnataka India

We have developed an efficient fully three-dimensional (3D) reconstruction algorithm for diffuse optical tomography (DOT). The 3D DOT, a severely ill-posed problem, is tackled through a pseudodynamic (PD) approach wherein an ordinary differential equation representing the evolution of the solution on pseudotime is integrated that bypasses an explicit inversion of the associated, ill-conditioned system matrix. One of the most computationally expensive parts of the iterative DOT algorithm, the reevaluation of the Jacobian in each of the iterations, is avoided by using the adjoint-Broyden update formula to provide low rank updates to the Jacobian. In addition, wherever feasible, we have also made the algorithm efficient by integrating along the quadratic path provided by the perturbation equation containing the Hessian. These algorithms are then proven by reconstruction, using simulated and experimental data and verifying the PD results with those from the popular Gauss-Newton scheme. The major findings of this work are as follows: (i) the PD reconstructions are comparatively artifact free, providing superior absorption coefficient maps in terms of quantitative accuracy and contrast recovery;(ii) the scaling of computation time with the dimension of the measurement set is much less steep with the Jacobian update formula in place than without it;and (iii) an increase in the data dimension, even though it renders the reconstruction problem less ill conditioned and thus provides relatively artifact-free reconstructions, does not necessarily provide better contrast property recovery. For the latter, one should also take care to uniformly distribute the measurement points, avoiding regions close to the source so that the relative strength of the derivatives for measurements away from the source does not become insignificant. (c) 2012 Optical Society of America

关键词： Absorption coefficient Diffuse optical tomography Light propagation Multiple scattering Photon diffusion reconstruction algorithms

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APPLICATION OF THE SINE-TRANSFORM METHOD IN TIME-OF-FLIGHT POSITRON-EMISSION IMAGE-reconstruction algorithms

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 1985年第3期32卷 185-192页

作者： CHENG, SNC WASHINGTON UNIV DEPT ELECT ENGNST LOUISMO 63130 WASHINGTON UNIV BIOMED COMP LABST LOUISMO 63130

The image reconstruction algorithms for time-of-flight positron-emission tomography systems are formulated as linear systems described by nonseparable, block-banded Toeplitz matrices, and sinetransform techniques are ... 详细信息

关键词： Image reconstruction Detectors Object detection Pixel Biomedical measurements reconstruction algorithms Biomedical computing Histograms Computer displays Image storage

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DESIGN CONSTRAINTS AND reconstruction algorithms FOR TRAVERSE-CONTINUOUS-ROTATE CT SCANNERS

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 1981年第2期28卷 79-98页

作者： NAHAMOO, D CRAWFORD, CR KAK, AC School of Engineering Purdue University West Lafayette IN USA

In this paper a new configuration for a computerized tomographic (CT) scanner is presented. The machine is essentially a hybrid combination of second- and third-generation scanners. A single source of X-rays and an array of detectors are mounted on a gantry. The source/detector array grouping traverses the object while the gantry continuously rotates around the object. Conditions will be derived so that the projection data will completely cover the Radon space without any holes or partial overlaps, thus ensuring the existence of efficiently implementable reconstruction algorithms for inverting the data. We will also present a new convolution-backprojection algorithm for reconstructing tomographic images from data generated on such a scanner.

关键词： Algorithm design and analysis reconstruction algorithms Computed tomography Detectors Sensor arrays Object detection Data acquisition Costs Image reconstruction X-rays

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Comparing lesion detection performance for PET image reconstruction algorithms: A case study

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1997年第4期44卷 1558-1563页

作者： Chan, MT Leahy, RM Mumcuoglu, EU Cherry, SR Czernin, J Chatziioannou, A UNIV SO CALIF DEPT EE SYST INST SIGNAL & IMAGE PROC LOS ANGELES CA 90089 USA UNIV CALIF LOS ANGELES SCH MED CRUMP INST BIOL IMAGING DIV IMAGING SCI LOS ANGELES CA 90024 USA

We present a comparison of the performance of filtered backprojection (FBP) and maximum a posteriori (MAP) reconstruction of PET images for the task of hot lesion detection. The comparison is performed on data generated by combining FDG chest scans of normal patients (i.e., without lesions) with pseudo-Poisson ''lesion'' data generated from appropriately scaled sinograms collected using a separately scanned 1.25 cm(3) spherical source. Scaling factors were used to achieve approximately 2.5:1 lesion-to-background activity ratios. A total of 60 ''abnormal'' cases were generated from their normal counterparts. A 3D non-prewhitening (NPW) observer model based on a matched filter was used to test for the presence of the lesion in the vicinity of the known lesion location, ROC curves were generated for several choices of cut-off frequency for ramp-filtered FBP and the smoothing parameter for the MAP reconstructions. The NPW detector was matched to the algorithm and smoothing parameter in each case. Our experiments show that MAP reconstruction over a range of smoothing parameter values results in statistically significant improvements, compared to FBP, for the task of lesion detection using a NPW observer.

关键词： Lesions Positron emission tomography Image reconstruction Computer aided software engineering Smoothing methods Humans Detectors reconstruction algorithms Bayesian methods Signal processing

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JKM PERTURBATION-THEORY, RELAXATION PERTURBATION-THEORY, AND THEIR APPLICATIONS TO INVERSE SCATTERING - THEORY AND reconstruction algorithms

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IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 1986年第6期33卷 722-730页

作者： LU, ZQ Department of Physics Nankai University Tianjin China

reconstruction algorithms of the high-order perturbation approximation under Born and Rytov transforms according to the JKM inverse scattering perturbation theory are provided, and their physical interpretations as multiscatterer and multi-inverse-interaction models are presented. Furthermore, a new perturbation theory called relaxation perturbation theory is suggested. All these aim to solve the moderately or strongly scattering problems occuring in ultrasonic diffraction tomography and to improve tomograms' resolution. All these reconstruction algorithms are similar in form to those in the conventional first-order Born or Rytov approximation. Copyright © 1986 by The Institute of Electrical and Electronics Engineers, Inc.

关键词： Inverse problems reconstruction algorithms Scattering Diffraction Tomography Refractive index Approximation algorithms Integral equations Image reconstruction Approximation methods

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Stability of radiomic features from positron emission tomography images: a phantom study comparing advanced reconstruction algorithms and ordered subset expectation maximization

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PHYSICAL AND ENGINEERING SCIENCES IN MEDICINE 2024年第3期47卷 929-937页

作者： Shiiba, Takuro Watanabe, Masanori Fujita Hlth Univ Sch Med Sci Dept Mol Imaging Clin & Collaborat Unit 1-98 DengakugakuboKutsukake Cho Toyoake Aichi 4701192 Japan Fujita Hlth Univ Hosp Dept Radiol 1-98 DengakugakuboKutsukake Cho Toyoake Aichi 4701192 Japan

In this study, we compared the repeatability and reproducibility of radiomic features obtained from positron emission tomography (PET) images according to the reconstruction algorithm used-advanced reconstruction algorithms, such as HYPER iterative (IT), HYPER deep learning reconstruction (DLR), and HYPER deep progressive reconstruction (DPR), or traditional Ordered Subset Expectation Maximization (OSEM)-to understand the potential variations and implications of using advanced reconstruction techniques in PET-based radiomics. We used a heterogeneous phantom with acrylic spherical beads (4- or 8-mm diameter) filled with 18F. PET images were acquired and reconstructed using OSEM, IT, DLR, and DPR. Original and wavelet radiomic features were calculated using SlicerRadiomics. Radiomic feature repeatability was assessed using the Coefficient of Variance (COV) and intraclass correlation coefficient (ICC), and inter-acquisition time reproducibility was assessed using the concordance correlation coefficient (CCC). For the 4- and 8-mm diameter beads phantom, the proportion of radiomic features with a COV < 10% was equivocal or higher for the advanced reconstruction algorithm than for OSEM. ICC indicated that advanced methods generally outperformed OSEM in repeatability, except for the original features of the 8-mm beads phantom. In the inter-acquisition time reproducibility analysis, the combinations of 3 and 5 min exhibited the highest reproducibility in both phantoms, with IT and DPR showing the highest proportion of radiomic features with CCC > 0.8. Advanced reconstruction methods provided enhanced stability of radiomic features compared with OSEM, suggesting their potential for optimal image reconstruction in PET-based radiomics, offering potential benefits in clinical diagnostics and prognostics.

关键词： Ordered subset expectation maximization Positron emission tomography Radiomic features reconstruction algorithms Stability

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COMPARING reconstruction algorithms FOR ELECTRICAL-IMPEDANCE TOMOGRAPHY

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 1987年第11期34卷 843-852页

作者： YORKEY, TJ WEBSTER, JG TOMPKINS, WJ UNIV WISCONSIN DEPT ELECT & COMP ENGN MADISON WI 53706 USA

An improved electrical impedance tomographic reconstruction algorithm is presented that is generally guaranteed to converge. The algorithm is attractive for several reasons. A modified Newton-Raphson method varies a finite-element model of resistivities to fit a set of voltage measurements in a least-squared sense. Two procedures for calculating the Jacobian matrix are derived. One is standard, while the other is based on the compensation theorem. This second procedure is more efficient for computations, and just as accurate as the standard one. The inherent ill-conditioning in the approximate Hessian matrix of the linearized system is eliminated using the Marquardt method. Results from two-dimensional computer simulations are compared to four other reconstruction algorithms, which are based on methods proposed by other authors. The modified Newton-Raphson method provided significantly better reconstructions than any of the other methods. The algorithms compared are the perturbation, equipotential, iterative-equipotential, and the double-constraint methods. The modified Newton-Raphson method was found to be sensitive to measurement error, but future work in designing electrode-probing configurations is expected to reduce this sensitivity.

关键词： reconstruction algorithms Impedance Tomography Jacobian matrices Finite element methods Conductivity Voltage measurement Computer simulation Iterative algorithms Measurement errors

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ON THE EQUIVALENCE OF NONLINEAR POSITIVE FEEDBACK-CIRCUITS TO CONSTRAINED ITERATIVE SIGNAL reconstruction algorithms

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-ANALOG AND DIGITAL SIGNAL PROCESSING 1993年第7期40卷 455-457页

作者： TARATORIN, AM SIDEMAN, S Heart System Research Center The Julius Silver Institute Department of Biomedical Engineering Technion-Israel Institute of Technology Haifa Israel

Constrained nonlinear iterative algorithms for signal restoration and reconstruction from zero crossings or clipped signals have a common structure of iterations and can be written as an infinite nonlinear operator series. This operator series corresponds to an analog nonlinear positive feedback circuit: the signal transformation, after an infinite number of iterations, is equivalent to the signal obtained by passing through the nonlinear instantaneous positive-feedback analog circuit. The corresponding structures of the feedback circuits for two reconstruction algorithms are presented. This interpretation offers interesting possibilities for real time signal reconstruction.

关键词： Feedback circuits Signal reconstruction Iterative algorithms Signal restoration Nonlinear distortion Nonlinear filters Analog circuits reconstruction algorithms Absorption Heart

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Comparison of the Newton-Raphson and the spectral expansion impedance tomography reconstruction algorithms

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IEEE TRANSACTIONS ON MAGNETICS 1996年第3期32卷 1286-1289页

作者： Vadasz, D Sebestyen, I Technical University of Budapest Hungary

Impedance tomography reconstruction algorithms estimate the impedance distribution of a body segment from impedance measurements between electrodes placed on the surface of the body. Two such algorithms, the modified Newton-Raphson algorithm and the reconstruction procedure offered by the spectral analysis method are compared both numerically and analytically. It is found that if the two methods are regularised equivalently, then the spectral reconstruction is identical to one step of the Newton-Raphson algorithm, The formulas of the equivalent regularisation are given, This finding allows the transfer of regularisation methods between the two reconstruction algorithms.

关键词： Surface impedance reconstruction algorithms Tomography Impedance measurement Electrodes Surface reconstruction Spectral analysis Algorithm design and analysis

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