نتایج جستجو برای: osem
تعداد نتایج: 265 فیلتر نتایج به سال:
UNLABELLED Tumor detection depends on the contrast between tumor activity and background activity and on the image noise in these 2 regions. The lower the image noise, the easier the tumor detection. Tumor activity contrast is determined by physiology. Noise, however, is affected by many factors, including the choice of reconstruction algorithm. Previous simulation and phantom measurements indi...
OBJECTIVE S Various iterative reconstruction algorithms in nuclear medicine have been introduced in the last three decades. For each new imaging system, it is wise to select appropriate image reconstruction algorithms and evaluate their performance. In this study, three approaches of image reconstruction were developed for a novel desktop open-gantry SPECT system, PERSPECT, to assess their perf...
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 ...
Abstract Background Q.Clear is a Bayesian penalized likelihood (BPL) reconstruction algorithm that presents improvements in signal-to-noise ratio (SNR) clinical positron emission tomography (PET) scans. Brain studies research require provides good spatial resolution and accentuates contrast features however, filtered back-projection (FBP) not available on GE SIGNA PET-Magnetic Resonance (PET-MR...
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 ...
UNLABELLED Iterative reconstruction techniques such as an ordered subsets-expectation maximization (OSEM) algorithm can easily incorporated various physical models of attenuation or scatter. We implemented OSEM reconstruction algorithm incorporating compensation for distance-dependent blurring due to the collimator in SPECT. The algorithm was examined by computer simulation to estimate the accu...
OBJECTIVE The aim of this study was to characterize the optimal reconstruction parameters for ordered-subset expectation maximization (OSEM) with attenuation correction, scatter correction, and depth-dependent resolution recovery (OSEMACSCRR). We assessed the optimal parameters for OSEMACSCRR in an anthropomorphic torso phantom study, and evaluated the validity of the reconstruction parameters ...
At the experimental heavy ion tumor therapy facility at the GSI Darmstadt in-beam PET is operated. The in-beam PET data should be reconstructed as fast as possible (ideally, in real time), because they allow monitoring irregularities in beam delivery. To find a fast reconstruction algorithm with acceptable quality, MLEM [1] and OSEM [2] algorithms were compared for full-ring and dual-head geome...
UNLABELLED A crucial method for investigating patients with coronary artery disease (CAD) is the calculation of the left ventricular ejection fraction (LVEF). It is, consequently, imperative to precisely estimate the value of LVEF--a process that can be done with myocardial perfusion scintigraphy. Therefore, the present study aimed to establish and compare the estimation performance of the quan...
OBJECTIVES The aim of this study was to determine the optimal reconstruction parameters for iterative reconstruction in different devices and collimators for dopamine transporter (DaT) single-photon emission computed tomography (SPECT). The results were compared between filtered back projection (FBP) and different attenuation correction (AC) methods. METHODS An anthropomorphic striatal phanto...
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