نتایج جستجو برای: scatter

تعداد نتایج: 12375  

Journal: :iranian journal of medical physics 0
afshin akbarzadeh ph.d. student, department of medical physics and biomedical engineering and research center for science and technology in medicine, tehran university of medical sciences, tehran, iran mohammad rreza ay assistant professor in biomedical engineering, biomedical systems & medical physics dept., tehran university of medical sciences & research center for science and technology in medicine, tehran, iran. hossein ghadiri ph.d. student, department of medical physics and biomedical engineering and research center for science and technology in medicine, tehran university of medical sciences, tehran, iran saied sarkar associate professor in biomedical engineering, biomedical systems & medical physics dept., tehran university of medical sciences & research center for science and technology in medicine, tehran, iran.

introduction: one of the most important parameters in x-ray ct imaging is the noise induced by detected scattered radiation. the detected scattered radiation is completely dependent on the scanner geometry as well as size, shape and material of the scanned object. the magnitude and spatial distribution of the scattered radiation in x-ray ct should be quantified for development of robust scatter...

Journal: :iranian journal of nuclear medicine 0
mohsen hajizadeh saffar medical physics research center, school of medicine, mashhad university of medical sciences, mashhad, iran shabnam oloomi medical physics department, mashhad university of medical science, mashhad, iran peter knoll department of nuclear medicine, wilhelminenspital, vienna, austria hadi taleshi department of medical physics, faculty of medical sciences, tarbiat modares university, tehran, iran

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique t...

Afshin Akbarzadeh Hossein Ghadiri, Mohammad Rreza Ay, Saied Sarkar

Introduction: One of the most important parameters in x-ray CT imaging is the noise induced by detected scattered radiation. The detected scattered radiation is completely dependent on the scanner geometry as well as size, shape and material of the scanned object. The magnitude and spatial distribution of the scattered radiation in x-ray CT should be quantified for development of robust scatter...

Hadi Taleshi Mohsen Saffar Peter Knoll, Shabnam Oloomi

Introduction: Scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. Accurate estimation of scatter in projection data of SPECT is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. Methods: The objective of this paper is to develop and validate a scatter correction technique ...

Feature extraction performs an important role in improving hyperspectral image classification. Compared with parametric methods, nonparametric feature extraction methods have better performance when classes have no normal distribution. Besides, these methods can extract more features than what parametric feature extraction methods do. Nonparametric feature extraction methods use nonparametric s...

Ahmad Mostaar, Ghazaleh Sadrieh Khajoo Mahdi Salehi Barough Mohammad Ali Ostadrahimi

Introduction: In the last few decades, a lot of monte carlo codes have been introduced for medical applications. this is important because through simulation, we are fully independent of the spectral scattering factor that we are not able measure in real terms. The effect of the radiation energy, the dimension of the radiation field, the sensitive volume of the ion chamber on t...

Journal: :مدیریت صنعتی 0
علی مروتی شریف آبادی استادیار گروه مدیریت صنعتی، دانشکدۀ اقتصاد، مدیریت و حسابداری دانشگاه یزد، یزد، ایران مهناز باروت کوب کارشناس‎ارشد مدیریت صنعتی، دانشکدۀ اقتصاد، مدیریت و حسابداری دانشگاه یزد، یزد، ایران

one of methods of improvement of the material flow is cross docking that in is considered as a good method to reduce inventory and improve customer satisfaction. too, the vehicle routing problem is one of the important problems in distribution management and its goal is to find paths for delivering various cargos. therefore, this study was conducted in order to vehicle routing problem with cros...

Journal: :iranian journal of basic medical sciences 0
shabnam oloomi department of medical physics, mashhad university of medical science, mashhad, iran hadi noori eskandari department of applied mathematics, school of mathematical sciences, ferdowsi university of mashhad, mashhad, iran seyed rasoul zakavi nuclear medicine research center, imam reza hospital, faculty of medicine, mashhad university of medical sciences, mashhad, iran peter knoll department of nuclear medicine wilhelminenspital vienna, austria faraz kalantari research center for nuclear medicine, tehran university of medical sciences, tehran, iran mohsen hajizadeh saffar department of medical physics, mashhad university of medical science, mashhad, iran

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

Journal: :iranian journal of nuclear medicine 2013
mohsen hajizadeh saffar shabnam oloomi peter knoll hadi taleshi

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique ...

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...

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