نتایج جستجو برای: ordered subsets expectation maximization
تعداد نتایج: 139368 فیلتر نتایج به سال:
The aim of this study was to validate in vivo the accuracy of a reconstruction-based partial volume correction (PVC), which takes into account the point spread function of the imaging system. The NEMA NU2 Image Quality phantom and five healthy volunteers (using [(11)C]flumazenil) were scanned on both HR+ and high-resolution research tomograph (HRRT) scanners. HR+ data were reconstructed using n...
The main objective of this work is to accelerate the MaximumLikelihood (ML) estimation procedure for radio interferometric direction dependent self-calibration. We introduce the OS-SAGE radio interferometric calibration method, as a combination of the Ordered-Subsets (OS) method with the Space Alternating Generalized Expectation maximization (SAGE) calibration technique. The OS method speeds up...
We present a pragmatic approach to image reconstruction for data from the micro crystal elements system (MiCES) fully 3D mouse imaging positron emission tomography (PET) scanner under construction at the University of Washington. Our approach is modelled on fully 3D image reconstruction used in clinical PET scanners, which is based on Fourier rebinning (FORE) followed by 2D iterative image reco...
BACKGROUND Our aim was to evaluate if a recently introduced TOF PET system with digital photon counting technology (Philips Healthcare), potentially providing an improved image quality over analogue systems, can fulfil EANM research Ltd (EARL) accreditation specifications for tumour imaging with FDG-PET/CT. FINDINGS We have performed a phantom study on a digital TOF PET system using a NEMA NU...
PURPOSE This paper describes a method to achieve consistent clinical image quality in (18)F-FDG scans accounting for patient habitus, dose regimen, image acquisition, and processing techniques. METHODS Oncological PET/CT scan data for 58 subjects were evaluated retrospectively to derive analytical curves that predict image quality. Patient noise equivalent count rate and coefficient of variat...
The nondestructive testing (NDT) of long object (such as pipeline) has significant value. Computed tomography (CT) is able to generate 3D images and display the inner defects of the inspected object. Sometimes the long object fixed outdoors can’t be rotated, and the rotating of the X-ray source and detector is also difficult. So the linear scan CT, translating the X-ray source and detector alon...
x f(x, θ) log f(x, θ) exists for all θ and θ. In principle, one can apply the sum-product algorithm in order to find (1), which involves the following two steps [2]: 1. Determine f(θ) by sum-product message passing. 2. Maximization step: compute θmax △ = argmaxθ f(θ). This procedure is often not feasible, since • When the variable x is continuous, the sum-product rule may lead to intractable in...
Objective(s): The aim of this study is to examine the effect of different smoothing filters on the image quality and SUVmax to achieve the guideline recommended positron emission tomography (PET) image without harmonization. Methods: We used a Biograph mCT PET scanner. A National Electrical Manufacturers Association (NEMA) the International Electrotechnical Commission (IEC) body phantom was fil...
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