نتایج جستجو برای: Attenuation, Emission data

تعداد نتایج: 2593617  

Journal: :iranian journal of nuclear medicine 2014
mahsa noori asl alireza sadremomtaz

the diagnostic accuracy of single photon emission computed tomography (spect) is profoundly influenced by attenuation phenomenon. soft tissue attenuation degrades cardiac spect image quality, thereby decreasing the possibility of the detection of the lesions. a variety of correction techniques based on different assumptions have been used to reduce the impact of attenuation. several types of sy...

Journal: :IEEE Transactions on Nuclear Science 2002

Journal: :iranian journal of nuclear medicine 2006
mohsen bakhshandeh hossein rajabi masoud vafamanesh ali akbar sharafi 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. these arti...

Journal: :Physics in medicine and biology 2009
Gengsheng L Zeng Grant T Gullberg

UNLABELLED It is common, even with new SPECT/CT systems, that the transmission data are truncated. This paper develops a method that obtains exact attenuation correction with truncated transmission data. The emission object (e.g., the heart) is assumed to have a finite, convex support, whose emission projections are not truncated. The transmission measurements over the support are available, bu...

The diagnostic accuracy of single photon emission computed tomography (SPECT) is profoundly influenced by attenuation phenomenon. Soft tissue attenuation degrades cardiac SPECT image quality, thereby decreasing the possibility of the detection of the lesions. A variety of correction techniques based on different assumptions have been used to reduce the impact of attenuation. Several types of sy...

Journal: :International Journal of Imaging Systems and Technology 2009

2004
Daniel Gourion Pierre Gantet Jean-Paul Esquerré

A major step towards quantitative SPECT imaging may be achieved if attenuation, scatter and blurring effects are accounted for in the reconstruction process. Here we consider an approach which simultaneously estimates the unknown attenuation coefficient and the emission source using the emission data only. This leads to an inverse mathematical problem which could no longer be solved via iterati...

2015
Ester D’Hoe Pieter Mollet Ekaterina Mikhaylova Michel Defrise Stefaan Vandenberghe

MEDISIP Medical Imaging and Signal Processing Group, Ghent University, IBBT-IBiTech, iMinds Medical IT, Ghent, Belgium In Time-of-Flight PET/MRI systems accurate attenuation correction, based on the MRI image, is not straight forward. An alternative is attenuation correction based on emission data only. This is for instance done by simultaneous reconstruction of attenuation and activity with th...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2008
K Lance Gould Tinsu Pan Catalin Loghin Nils P Johnson Stefano Sdringola

UNLABELLED Cardiac PET/CT is optimized by cine CT with dedicated shift software for manual correction of attenuation-emission misregistration. Separate rest and stress CT scans incur greater radiation dose to patients than does standard helical PET/CT or "pure" PET using rotating rod attenuation sources. To reduce radiation dose, we tested quantitative accuracy of using a single poststress cine...

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