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Evaluation of reconstruction Methods in X-ray Computed Tomography Geometric Measurement

Procedia CIRP 2024年 129卷 139-144页

作者： Kaojie Yue Huan Shao Stefano Petrò Giovanni Moroni Department of Mechanical Engineering Politecnico di Milano Via La Masa 1 Milano 20156 Italy

In X-ray Computed Tomography (XCT) geometric measurement, the reconstruction process is a main step that significantly influences acquisition strategies and measurement results. Analytical algorithms, primarily Feldkamp-Davis-Kress (FDK), and algebraic algorithms are commonly used for reconstruction, with FDK being the dominant choice for dimensional measurements. Although algebraic algorithms offer advantages like denoising and handling limited projections, their evaluation concerning measurement accuracy remains insufficient. To assess the performance with respect to measurement accuracy and sensitivity to acquisition parameters, we performed typical reconstruction algorithms on the measurements of diameter, cylindricity, and flatness, including FDK and ordered subsets simultaneously algebraic reconstruction technique (OS-SART). Moreover, the algorithm comprised in a commercial software was used and evaluated. Variables in acquisition included part orientation and exposure time. The analysis comparing XCT measurements with those from Coordinate Measuring Machine showed different performances of the two reconstruction algorithms and the potential of algebraic algorithms in XCT geometric measurement.

关键词： X-ray computed tomography Geometric measurement reconstruction algorithm

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Neutrino energy reconstruction in quasielastic-like scattering in the MiniBooNE and T2K experiments

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Physical Review C 2012年第5期86卷 054606-054606页

作者： O. Lalakulich U. Mosel K. Gallmeister Institut für Theoretische Physik Universität Giessen Germany Institut für Theoretische Physik Johann Wolfgang Goethe-Universität Frankfurt Germany

Background: Neutrino oscillation probabilities, which are being measured in long-baseline experiments, depend on neutrino energy. The energy in a neutrino beam, however, is broadly smeared so that the neutrino energy ... 详细信息

关键词： Cross section neutrino beams TANK-Binding Kinase 1 Reaction Mechanisms Energy sources pion production Neutrinos reconstruction algorithm

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Random sampling and reconstruction in multiply generated shift-invariant spaces

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ANALYSIS AND APPLICATIONS 2019年第2期17卷 323-347页

作者： Yang, Jianbin Hohai Univ Dept Math Coll Sci Nanjing 211100 Jiangsu Peoples R China

Shift-invariant spaces play an important role in approximation theory, wavelet analysis, finite elements, etc. In this paper, we consider the stability and reconstruction algorithm of random sampling in multiply generated shift-invariant spaces V-p(Phi). Under some decay conditions of the generator Phi, we approximate V-p(Phi) with finite-dimensional subspaces and prove that with overwhelming probability, the stability of sampling set conditions holds uniformly for all functions in certain compact subsets of V-p(Phi) when the sampling size is sufficiently large. Moreover, we show that this stability problem is connected with properties of the random matrix generated by Phi. In the end, we give a reconstruction algorithm for the random sampling of functions in V-p(Phi).

关键词： Random sampling covering number multiply shift-invariant spaces reconstruction algorithm

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reconstructions of conductive and insulating targets using the D-bar method on an elliptical domain

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PHYSIOLOGICAL MEASUREMENT 2007年第7期28卷 S101-S114页

作者： Murphy, E. K. Mueller, J. L. Newell, J. C. Colorado State Univ Dept Math Ft Collins CO 80523 USA Rensselaer Polytech Inst Dept Biomed Engn Troy NY 12180 USA

The D-bar algorithm based on A Nachman's 2D global uniqueness proof for the inverse conductivity problem (Nachman 1996 Ann. Math. 143 71-96) is implemented on an elliptical domain. The scattering transform is computed on an ellipse and the complete electrode model (CEM) for the forward problem is computed with the finite element method (FEM) in order to obtain static conductivity reconstructions of conductive and insulating targets in a saline-filled tank. It is demonstrated that the spatial artifacts in the image are significantly reduced when the domain is properly modeled in the reconstruction, as opposed to being modeled as a disk.

关键词： electrical impedance tomography reconstruction algorithm D-bar method elliptical tank

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Summary and closing remarks

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RADIATION PROTECTION DOSIMETRY 1998年第1-2期77卷 137-138页

作者： Sugahara, T Hlth Res Fdn Sakyo Ku Kyoto 606 Japan

As a summary of the Workshop, the programme items are reviewed and classified according to the purpose of each type of retrospective dosimetry. The reports are divided into four groups: accidents, environmental contamination, radiation workers and A bomb survivors. Problems in dose reconstruction are reviewed according to the suggestion by Till. Physical and biological dosimetry for dose reconstruction are also reviewed. Finally, continued international cooperation to improve dose reconstruction methods for accident and epidemiological study is proposed.

关键词： Dosimetry physical Accidents bombing equipments reconstruction algorithm

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Radiation dose reduction with the adaptive statistical iterative reconstruction (ASIR) technique for chest CT in children: An intra-individual comparison

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EUROPEAN JOURNAL OF RADIOLOGY 2012年第9期81卷 E938-E943页

作者： Lee, Seung Hyun Kim, Myung-Joon Yoon, Choon-Sik Lee, Mi-Jung Yonsei Univ Coll Med Dept Radiol Severance Childrens Hosp Seoul 120752 South Korea Yonsei Univ Coll Med Res Inst Radiol Sci Severance Childrens Hosp Seoul 120752 South Korea Yonsei Univ Coll Med Gangnam Severance Hosp Dept Radiol Seoul 120752 South Korea

Objective: To retrospectively compare radiation dose and image quality of pediatric chest CT using a routine dose protocol reconstructed with filtered back projection (FBP) (the Routine study) and a low-dose protocol with 50% adaptive statistical iterative reconstruction (ASIR) (the ASIR study). Materials and methods: We retrospectively reviewed chest CT performed in pediatric patients who underwent both the Routine study and the ASIR study on different days between January 2010 and August 2011. Volume CT dose indices (CTDIvol), dose length products (DLP), and effective doses were obtained to estimate radiation dose. The image quality was evaluated objectively as noise measured in the descending aorta and paraspinal muscle, and subjectively by three radiologists for noise, sharpness, artifacts, and diagnostic acceptability using a four-point scale. The paired Student's t-test and the Wilcoxon signed-rank test were used for statistical analysis. Results: Twenty-six patients (M: F = 13: 13, mean age 11.7) were enrolled. The ASIR studies showed 60.3%, 56.2%, and 55.2% reductions in CTDIvol (from 18.73 to 7.43 mGy, P < 0.001), DLP (from 307.42 to 134.51 mGy x cm, P < 0.001), and effective dose (from 4.12 to 1.84 mSv, P < 0.001), respectively, compared with the Routine studies. The objective noise was higher in the paraspinal muscle of the ASIR studies (20.81 vs. 16.67, P = 0.004), but was not different in the aorta (18.23 vs. 18.72, P = 0.726). The subjective image quality demonstrated no difference between the two studies. Conclusion: A low-dose protocol with 50% ASIR allows radiation dose reduction in pediatric chest CT by more than 55% while maintaining image quality. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

关键词： Adaptive statistical iterative reconstruction Image quality Radiation dose reconstruction algorithm CT

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The association of tumor-to-background ratios and SUVmax deviations related to point spread function and time-of-flight F18-FDG-PET/CT reconstruction in colorectal liver metastases

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EJNMMI RESEARCH 2015年第1期5卷 31-31页

作者： Rogasch, Julian M. M. Steffen, Ingo G. Hofheinz, Frank Grosser, Oliver S. Furth, Christian Mohnike, Konrad Hass, Peter Walke, Mathias Apostolova, Ivayla Amthauer, Holger Otto Von Guericke Univ Univ Klinikum Magdeburg AoR Klin Radiol & Nuklearmed D-39120 Magdeburg Germany Inst Radiopharmaceut Canc Res Helmholtz Zentrum Dresden Rossendorf PET Ctr D-01328 Dresden Germany Otto Von Guericke Univ Univ Klinikum Magdeburg AoR Klin Strahlentherapie D-39120 Magdeburg Germany

Background: The maximum standardized uptake value (SUVmax) is a common clinical parameter for quantification in F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), but it is influenced by image reconstruction. The aim of this study was to analyze the association of SUVmax deviations related to point spread function (PSF) and time-of-flight (TOF) reconstruction with tumor-to-background ratios (TBR) in colorectal liver metastases (CRLM). Methods: Fifteen patients (f, 6;m, 9;median age, 59 years;range, 32 to 72 years) with 28 liver metastases were included retrospectively. FDG-PET/CT imaging (median activity, 237 MBq;range, 231 to 252 MBq;median uptake, 61 min;range, 55 to 67 min) was performed on a Siemens Biograph mCT 64 followed by image reconstruction using 3D-ordered subset expectation maximization (3D-OSEM) or 3D-OSEM with PSF modeling - both with and without TOF information. Differences in SUVmax were analyzed using the Friedman test and Wilcoxon test for paired non-parametric data. The correlation of inter-method differences with the lesions' TBR was studied using Spearman's rank correlation coefficient (rho). Differences between lesions with low (<4.8) and high (>4.8) TBR were analyzed using the Mann-Whitney U test (TBR measured with 3D-OSEM;binarized by its median). Results: There was a significant correlation of the lesions' TBR with relative SUVmax differences related to PSF (PSF + TOF vs. 3D-OSEM + TOF, rho = 0.61;PSF vs. 3D-OSEM, rho = 0.52) or TOF (PSF + TOF vs. PSF, rho = -0.58;3D-OSEM + TOF vs. 3D-OSEM, rho = -0.61). Accordingly, PSF algorithms only showed higher SUVmax than non-PSF algorithms in lesions with a high TBR (median differences at low/high TBR, + 2.6%/+9.1% [PSF + TOF vs. 3D-OSEM + TOF];+ 0.7%/+6.4% [PSF vs. 3D-OSEM]). TOF integration also led to higher SUVmax but mainly at low TBR (low/high TBR, + 10.4%/+1.8% [PSF + TOF vs. PSF];+ 8.6%/-0.1% [3D-OSEM + TOF vs. 3D-OSEM]). Conclusions: Both PSF and TOF recon

关键词： F18-FDG-PET/CT SUVmax reconstruction algorithm PSF TOF Tumor-to-background ratio Colorectal liver metastases Target volume definition

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Virtual compressed sensing photoacoustic tomography with high-detection efficiency using k-wave

Virtual compressed sensing photoacoustic tomography with hig...

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Conference on Nano-, Bio-, Info-Tech Sensors and Wearable Systems

作者： Zhao, Aojie Liu, Jiahui He, Qiming Li, Bo Zhang, Jinhong Wei, Jianshuang Song, Lingfang Song, Xianlin Nanchang Univ Sch Informat Engn Nanchang 330031 Jiangxi Peoples R China Nanchang Univ Sch Sci Nanchang 330031 Jiangxi Peoples R China Huazhong Univ Sci & Technol Britton Chance Ctr Biomed Photon Wuhan Natl Lab Optoelect Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Dept Biomed Engn Minist Educ Moe Key Lab Biomed Photon Wuhan 430074 Hubei Peoples R China Nanchang Normal Univ Nanchang 330031 Jiangxi Peoples R China

ISBN: (数字)9781510640108

ISBN: (纸本)9781510640108

In recent years, photoacoustic imaging, an emerging nondestructive biomedical imaging technology, has shown great potential for early diagnosis of diseases with its advantages of highly sensitive optical contrast and high resolution. It is a hard project to collect a large number of pathological medical images by using photoacoustic imaging. How to compress large amounts of data, rapid transmission and storage of important value information has become an urgent problem to be solved. In this paper, build a virtual simulation platform for compressed sensing photoacoustic tomography by combining compressed sensing reconstruction algorithms with photoacoustic imaging based on the k-wave simulation toolbox. On the one hand, compressed sensing can reduce sample rates, accelerated the speed of imaging. On the other hand, it can modify the demands for hardware devices and facilitate to transmit and store of data. The k-wave simulation toolbox is used to build simulation models for simulating the propagation of photoacoustic fields, recording of photoacoustic signals, and image reconstruction. We validated the performance of the simulation platform by imaging the vascular network. The results show that the virtual simulation platform compressed sensing photoacoustic tomography can achieve high-quality photoacoustic imaging with less data. The virtual platform can provide theoretical guidance for the application of compressed sensing in photoacoustic imaging.

关键词： photoacoustic tomography compression sensing k-wave simulation toolbox reconstruction algorithm

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An Improved Sparsity Adaptive Matching Pursuit algorithm for Sparse Channel Estimation 10

An Improved Sparsity Adaptive Matching Pursuit Algorithm for...

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10th International Workshop on Signal Design and its Applications in Communications (IWSDA)

作者： Bai, Chaoyuan Yang, Liu Fan, Pingzhi Southwest Jiaotong Univ CSNMT Int Coop Res Ctr MoST Informat Coding & Transmiss Key Lab Sichuan Prov Chengdu 611756 Sichuan Peoples R China Natl Engn Lab Integrated Transportat Big Data App Chengdu 611756 Sichuan Peoples R China

ISBN: (数字)9781665452984

ISBN: (纸本)9781665452984

It is known that wireless channel is sparse in most cases, and this makes it possible to estimate channel with compressed sensing(CS). In this paper, an improved greedy reconstruction algorithm is proposed for sparse signal, i.e. variable step-size sparsity adaptive matching pursuit (SAMP) algorithm based on Dice coefficient and variable step-size(DV). In the proposed DV-SAMP algorithm, the similarity calculation method is optimized first, and then, the estimated sparsity is used to approach the real sparsity accurately and quickly with the variable step-size. Our simulation results show that the proposed DV-SAMP algorithm outperforms the SAMP and other greedy reconstruction algorithms in reconstructing sparse signals.

关键词： compressed sensing reconstruction algorithm variable step-size Dice coefficient channel estimation

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Effect of radiation dose and iterative reconstruction on lung lesion conspicuity at MDCT: Does one size fit all?

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EUROPEAN JOURNAL OF RADIOLOGY 2013年第11期82卷 E726-E733页

作者： Botelho, Marcos Paulo Ferreira Agrawal, Rishi Gonzalez-Guindalini, Fernanda Dias Hart, Eric M. Patel, Suresh K. Toere, Hueseyin Guerkan Yaghmai, Vahid Northwestern Univ Feinberg Sch Med Dept Radiol Northwestern Mem Hosp Chicago IL 60611 USA

Objective: To evaluate the effect of different acquisition parameters and reconstruction algorithms in lung lesions conspicuity in chest MDCT. Methods: An anthropomorphic chest phantom containing 6 models of lung disease (ground glass opacity, bronchial polyp, solid nodule, ground glass nodule, emphysema and tree-in-bud) was scanned using 80, 100 and 120 kVp, with fixed mAs ranging from 10 to 110. The scans were reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Three blinded thoracic radiologists reviewed the images and scored lesions conspicuity and overall image quality. Image noise and radiation dose parameters were recorded. Results: All acquisitions with 120 kVp received a score of 3 (acceptable) or higher for overall image quality. There was no significant difference between IR and FBP within each setting for overall image quality (p > 0.05), even though image noise was significantly lower using IR (p < 0.0001). When comparing specific lower radiation acquisition parameters 100 kVp/10 mAs [Effective Dose (ED): 0.238 mSv] vs 120 kVp/10 mAs (ED: 0.406 mSv) vs 80 kVp/40 mAs (ED: 0.434 mSv), we observed significant difference in lesions conspicuity (p < 0.02), as well as significant difference in overall image quality, independent of the reconstruction algorithm (p < 0.02), with higher scores on the 120 kV/10 mAs setting. Tree-in-bud pattern, ground glass nodule and ground glass opacity required lower radiation doses to get a diagnostic score using IR when compared to FBP. Conclusion: Designing protocols for specific lung pathologies using lower dose acquisition parameters is feasible, and by applying iterative reconstruction, radiologists may have better diagnostic confidence to evaluate some lesions in very low dose settings, preserving acceptable image quality. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

关键词： CT Lung lesions Conspicuity Radiation dose reconstruction algorithm

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