نتایج جستجو برای: osem

تعداد نتایج: 265  

Objective: The aim of this study was to evaluate the influences of reconstruction and attenuation correction on the differences in the radioactivity distributions in 123I brain SPECT obtained by the hybrid SPECT/CT device. Methods: We used the 3-dimensional (3D) brain phantom, which imitates the precise structure of gray mater, white matter and bone regions. It was filled with 123I solution (20...

Journal: :Annals of nuclear medicine 2015
Takafumi Taniguchi Go Akamatsu Yukiko Kasahara Katsuhiko Mitsumoto Shingo Baba Yuji Tsutsui Kazuhiko Himuro Shohei Mikasa Daisuke Kidera Masayuki Sasaki

OBJECTIVE The aim of this study was to evaluate the effect of the point spread function (PSF) and time of flight (TOF) on PET/CT images of overweight patients in relation to the iteration number and the acquisition time. METHODS This study consisted of a phantom study and a clinical study. The NEMA IEC body phantom and a 40 cm diameter large phantom (LG phantom) simulating an overweight patie...

Journal: :Journal of nuclear medicine technology 2015
Ida Häggström Jan Axelsson Charles Ross Schmidtlein Mikael Karlsson Anders Garpebring Lennart Johansson Jens Sörensen Anne Larsson

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...

2017
Jim O’ Doherty Daniel R. McGowan Carla Abreu Sally Barrington

ABSTACT OBJECTIVES: Myocardial blood flow (MBF) imaging is used in patients with suspected cardiac sarcoidosis, and also in stress/rest studies. The accuracy of MBF is dependent on imaging parameters such as new reconstruction methodologies. In this work, we aim to assess the impact of a novel PET reconstruction algorithm (Bayesian-penalized likelihood-BPL) on the values determined from the cal...

1997
C. A. Johnson J. Seidel R. E. Carson

The use of paired, opposing position-sensitive phototube scintillation cameras (SCs) operating in coincidence for small animal imaging with positron emitters is currently under study. Because of the low sensitivity of the system even in 3D mode and the need to produce images with high resolution, it was postulated that a 3D expectation maximization (EM) reconstruction algorithm might be well su...

2015
Takeshi Tomiyama Keiichi Ishihara Masaya Suda Koji Kanaya Minoru Sakurai Naoto Takahashi Hitoshi Takano Koichi Nitta Kenta Hakozaki Shin-ichiro Kumita

BACKGROUND The impact of time-of-flight (TOF) in myocardial perfusion (13)N-ammonia positron emission tomography (PET) is unclear. METHODS AND RESULTS Twenty consecutive subjects underwent rest and adenosine stress (13)N-ammonia myocardial perfusion PET. Two sets of images were reconstructed using TOF-ordered subset expectation maximization (TOF-OSEM) and 3-dimensional row-action maximum like...

Journal: :Nuclear medicine communications 2015
Ceri E Ashton Susan C Doyle Stewart Redman Richard Graham Gordon J Taylor Martyn J Evans

PURPOSE In order to locally validate the technique, a retrospective review of a cohort of randomly selected single-photon emission computed tomography (SPECT) bone scans reconstructed with ordered subsets expectation maximization (OSEM) and Evolution for Bone was undertaken. MATERIALS AND METHODS Thirty consecutive bone SPECT patient data sets (17 spine, nine pelvis, and four spine and pelvis...

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 p...

Journal: :Hellenic journal of nuclear medicine 2013
Masato Kobayashi Hiroshi Wakabayashi Hironori Kojima Takahiro Konishi Koichi Okuda Hiroto Yoneyama Daiki Kayano Minoru Tobisaka Hiroyuki Tsushima Masahisa Onoguchi Keiichi Kawai Seigo Kinuya

Whole-body and single photon emission tomography (SPET) images during sodium iodide-131 (Na131I) ablation are useful to confirm the efficacy of ablation using 131I imaging. However, there have been no attempts to improve the quality of 131I imaging. We therefore investigated imaging protocols for 131I imaging in differentiated thyroid cancer (DTC). Phantoms containing 131I were used to simulate...

Journal: :Journal of nuclear medicine technology 2006
Seyed Rasoul Zakavi Amin Zonoozi Vahidreza Dabbagh Kakhki Mohsen Hajizadeh Mehdi Momennezhad Kamran Ariana

UNLABELLED Patient motion during myocardial perfusion SPECT is a common source of errors. The extent and severity of motion artifacts have been described for filtered backprojection (FBP) reconstruction. In recent years, iterative reconstruction has been used increasingly in reconstruction of myocardial perfusion SPECT images and has been shown to be more accurate than FBP even in cases of inco...

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