نتایج جستجو برای: phantom scatter factor

تعداد نتایج: 870740  

Journal: :BioMed research international 2016
Sorapong Aootaphao Saowapak S Thongvigitmanee Jartuwat Rajruangrabin Chalinee Thanasupsombat Tanapon Srivongsa Pairash Thajchayapong

Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work,...

Journal: :IEEE Trans. Med. Imaging 1999
Gengsheng Lawrence Zeng Chuanyong Bai Grant T. Gullberg

Scatter correction is an important factor in single photon emission computed tomography (SPECT). Many scatter correction techniques, such as multiple-window subtraction and intrinsic modeling with iterative algorithms, have been under study for many years. Previously, we developed an efficient slice-to-slice blurring technique to model attenuation and system geometric response in a projectorhac...

Journal: :Journal of Physics: Conference Series 2007

2012
Nadège Anizan Thomas Carlier Cecilia Hindorf Jacques Barbet

Background: Noninvasive multimodality imaging is essential for preclinical evaluation of the biodistribution and pharmacokinetics of radionuclide therapy and for monitoring tumor response. Imaging with nonstandard positronemission tomography [PET] isotopes such as I is promising in that context but requires accurate activity quantification. The decay scheme of I implies an optimization of both ...

Journal: :Physics in medicine and biology 2011
G Poludniowski P M Evans A Kavanagh S Webb

Scatter in a detector and its housing can result in image degradation. Typically, such scatter leads to a low-spatial frequency 'glare' superimposed on the primary signal. We infer the glare-spread function (GSF) of an amorphous-silicon flat-panel detector via an edge-spread technique. We demonstrate that this spread (referred to as 'scatter-glare' herein) causes a low-spatial frequency drop in...

Journal: :iranian journal of medical physics 0
mohammad taghi bahreyni toossi medical physics research center, medical physics department, mashhad university of medical sciences, mashhad, iran

introduction spect projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. backscatter constitutes a major part of the scatter contamination in lower energy windows. the current study is an evaluation of the effect of backscatter material on fwhm and image quality investigated by monte carlo simulation. materials and methods simind program...

Jalil Pirayesh Islamian Mahdi Momennezhad Mohammad Taghi Bahreyni Toossi, Ramin Sadeghi Seyyed Rasool Zakavi

Introduction SPECT projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. Backscatter constitutes a major part of the scatter contamination in lower energy windows. The current study is an evaluation of the effect of backscatter material on FWHM and image quality investigated by Monte Carlo simulation. Materials and Methods SIMIND program...

A. Takavar, Gh. Shamsipour, M. Eftekhari, M. Sohrabi,

Background: In myocardial perfusion SPECT imaging, images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. Filters greatly affect quality of nuclear medicine images Materials and Methods: A phantom simulating heart left ventricle was built. About 1mCi of 99mTc was injected into the phantom. Images were taken from this phantom. Some fi...

2012
Nadège Anizan Thomas Carlier Cecilia Hindorf Jacques Barbet Manuel Bardiès

BACKGROUND Noninvasive multimodality imaging is essential for preclinical evaluation of the biodistribution and pharmacokinetics of radionuclide therapy and for monitoring tumor response. Imaging with nonstandard positron-emission tomography [PET] isotopes such as 124I is promising in that context but requires accurate activity quantification. The decay scheme of 124I implies an optimization of...

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