نتایج جستجو برای: attenuation emission data

تعداد نتایج: 2593617  

2014
Yannick Berker Volkmar Schulz

Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany Despite promising advances, attenuation correction of PET data remains challenging in PET/MRI. Known approaches to estimating attenuation maps from PET emission data take into account only true coincidences and fail to completely determine the attenuation map...

2017
Benjamin Noto Florian Büther Katharina Auf der Springe Nemanja Avramovic Walter Heindel Michael Schäfers Thomas Allkemper Lars Stegger

BACKGROUND While 68Ga-PSMA PET-MRI might be superior to PET-CT with regard to soft tissue assessment in prostate cancer evaluation, it is also known to potentially introduce additional PET image artefacts. Therefore, the impact of PET acquisition duration and attenuation data on artefact occurrence, lesion detectability, and quantification was investigated. To this end, whole-body PET list mode...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2007
Axel Martinez-Möller Michael Souvatzoglou Nassir Navab Markus Schwaiger Stephan G Nekolla

UNLABELLED CT-based attenuation correction is a widely used option in commercial PET/CT scanners. However, as a result of a nonsimultaneous acquisition and differences in temporal resolution between both modalities, a potential misregistration between the PET and CT, especially in the thorax and the upper abdomen, can be found. We observed a substantial number of apparent perfusion defects in s...

2015
Yukito Maeda Nobuyuki Kudomi Yasuhiro Sasakawa Toshihide Monden Koji Kato Yuka Yamamoto Nobuyuki Kawai Yoshihiro Nishiyama

BACKGROUND Cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) images have facilitated understanding of the pathophysiological basis of cerebrovascular disorders. Such parametric images can be rapidly, measured within around 15 min, using positron emission tomography (PET) with sequentially administered (15)O-labeled oxygen and water. For f...

1998
U. Ruotsalainen

Quantitative PET studies require computing of the attenuation correction factors (ACF) for compensating the body attenuation effect in the emission data. Short acquisition times for transmission are desired, because of patient comfort and movement elimination. In practice, long acquisition times are used due to the statistical noise of count-limited scans. In order to reduce the noise, the medi...

Ali Akbar Sharafi Hossein Rajabi, Masoud Vafamanesh Mohsen Bakhshandeh Shahram Seifollahi

Introduction: Nowadays, Imaging of the myocardial perfusion (MPI) using the single photon emission tomography (SPET) in the diagnosis of coronary artery disease, especially myocardial ischemia, is of great importance. In contrast to the coronary artery angiography, MPI is non-invasive, less expensive and more physiological. Unfortunately, this image is affected by the some artifacts. Thes...

2000
J. Nuyts

In positron emission tomography, transmission scans are used to correct the acquired data for the effect of photon attenuation. The noise present in the transmission measurement often has a significant effect on the signal to noise ratio of the final attenuation corrected image of the tracer distribution. This study evaluates the effect of different attenuation correction strategies on the perf...

Journal: :Medical physics 2016
Abolfazl Mehranian Hossein Arabi Habib Zaidi

Attenuation correction is an essential component of the long chain of data correction techniques required to achieve the full potential of quantitative positron emission tomography (PET) imaging. The development of combined PET/magnetic resonance imaging (MRI) systems mandated the widespread interest in developing novel strategies for deriving accurate attenuation maps with the aim to improve t...

Journal: :Physics in medicine and biology 2007
M K Nguyen T T Truong J L Delarbre Ch Roux H Zaidi

Transmission scanning-based estimation of the attenuation map plays a crucial role in quantitative radionuclide imaging. X-ray computed tomography (CT) reconstructs directly the attenuation coefficients map from data transmitted through the object. This paper proposes an alternative route for reconstructing the object attenuation map by exploiting Compton scatter of transmitted radiation from a...

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