نتایج جستجو برای: scatter correction

تعداد نتایج: 176847  

Journal: :Medical physics 2014
Ida Häggström C Ross Schmidtlein Mikael Karlsson Anne Larsson

PURPOSE The aim of this study was to investigate the effect of scatter and its correction on kinetic parameters in dynamic brain positron emission tomography (PET) tumor imaging. The 2-tissue compartment model was used, and two different reconstruction methods and two scatter correction (SC) schemes were investigated. METHODS The gate Monte Carlo (MC) software was used to perform 2 × 15 full ...

Journal: :Physics in medicine and biology 2009
G Poludniowski P M Evans V N Hansen S Webb

A new method is proposed for scatter-correction of cone-beam CT images. A coarse reconstruction is used in initial iteration steps. Modelling of the x-ray tube spectra and detector response are included in the algorithm. Photon diffusion inside the imaging subject is calculated using the Monte Carlo method. Photon scoring at the detector is calculated using forced detection to a fixed set of no...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2001
F Harel R Génin D Daou R Lebtahi N Delahaye B O Helal D Le Guludec M Faraggi

UNLABELLED A lack of specificity for myocardial perfusion imaging has been widely reported, mostly related to false-positive defects on the inferior wall. The application of depth-dependent resolution recovery (RR), attenuation correction (AC) using external source devices, and scatter correction has been proposed to resolve this pitfall. METHODS We studied the clinical benefit of depth-depen...

Journal: :Investigative ophthalmology & visual science 1994
D Whitaker D B Elliott R Steen

PURPOSE To reevaluate the validity of the light scatter factor (LSF) formula of Paulsson and Sjöstrand, LSF = L/E (M2/M1-1), where L is the target luminance, E is the illuminance of the glare source at the eye, and M2 and M1 are modulation contrast thresholds measured with and without the glare source, respectively. This equation has recently been deemed invalid by Yager, Yuan, and Mathews. M...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2003
Marine Soret Pierre Malick Koulibaly Jacques Darcourt Sébastien Hapdey Irène Buvat

UNLABELLED 123I-Labeled radiotracers are suitable for in vivo imaging of the dopaminergic system by SPECT. However, precise measurement of striatal uptake is limited by scatter, attenuation, and the finite spatial resolution of the camera. We studied the quantitative accuracy that can be achieved with (123)I SPECT of the dopaminergic neurotransmission system. METHODS Using a Monte Carlo simul...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2001
N Tamaki Y Kuge E Tsukamoto

Myocardial perfusion SPECT has been established as a noninvasive method for evaluation of coronary artery disease. For semiquantitative analysis, myocardial activity is conventionally measured relative to the region of most intense uptake. On the other hand, the absolute measurement of megabecquerels of tracer per gram of tissue has been an elusive goal. For this purpose, several factors—includ...

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