نتایج جستجو برای: osem reconstruction
تعداد نتایج: 123248 فیلتر نتایج به سال:
UNLABELLED Compartmental modeling of dynamic PET data enables quantification of tracer kinetics in vivo, through the calculated model parameters. In this study, we aimed to investigate the effect of early frame sampling and reconstruction method on pharmacokinetic parameters obtained from a 2-tissue model, in terms of bias and uncertainty (SD). METHODS The GATE Monte Carlo software was used t...
Statistical reconstruction has become popular in emission computed tomography but suffers slow convergence (to the MAP or ML solution). Methods proposed to address this problem include the fast but non-convergent OSEM and the convergent RAMLA [1] for the ML case, and the convergent BSREM [2], relaxed OS-SPS and modified BSREM [3] for the MAP case. The convergent algorithms required a user-deter...
Objective(s): In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. Methods: Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; a...
The reconstruction of dynamic PET data is usually performed using filtered backprojection algorithms (FBP). This method is fast, robust, linear and yields reliable quantitative results. However, the use of FBP for low count data, such as dynamic PET data, generally results in poor visual image quality, exhibiting high noise, disturbing streak artifacts and low contrast. These signal-to-noise ra...
Abstract To evaluate whether quantitative PET parameters of motion-corrected 68 Ga-DOTATATE PET/CT can differentiate between intrapancreatic accessory spleens (IPAS) and pancreatic neuroendocrine tumor (pNET). A total 498 consecutive patients with tumors (NET) who underwent March 2017 July 2019 were retrospectively analyzed. Subjects (n = 43, thereof 7 IPAS) pNET 9) included, resulting in a 45 ...
It is expected that both noise and activity distribution can have impact on the detectability of a myocardial defect in a cardiac PET study. In this work, we performed phantom studies to investigate the detectability of a defect in the myocardium for different noise levels and activity distributions. We evaluated the performance of three reconstruction schemes: Filtered Back-Projection (FBP), O...
We implemented a fully-3D ordered subsets expectation maximization (OSEM) algorithm with compensation of attenuation, distance-dependent blurring (DDB) and sensitivity modeling for SPECT performed with cone-beam collimator (CBC). The experimentally obtained detector response to point sources across FOV was fitted to a twodimensional Gauss function with its width (FWHM) varied linearly with the ...
OBJECTIVES In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. METHODS Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age...
Autoradiography (ARG) has been used for quantitative analysis of the cerebral blood flow using 123I-IMP, and the regional cerebral blood flow (rCBF) can be assessed more accurately with scatter and attenuation correction. Currently, the filtered back projection (FBP) method is generally used for image reconstruction. However, we anticipate obtaining more accurate rCBF by the ordered ...
We have studied the properties of the pixel updating coefficients in the 2D ordered subsets expectation maximization (OSEM) algorithm for iterative image reconstruction in positron emission tomography, in order to address the problem of image quality degradation-a known property of the technique after a number of iterations. The behavior of the updating coefficients has been extensively analyze...
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