نتایج جستجو برای: scatter system

تعداد نتایج: 2240877  

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...

Journal: :Japanese Journal of Radiological Technology 2002

Journal: :Medical physics 2009
Lei Zhu Jing Wang Lei Xing

Scatter correction is crucial to the quality of reconstructed images in x-ray cone-beam computed tomography (CBCT). Most of existing scatter correction methods assume smooth scatter distributions. The high-frequency scatter noise remains in the projection images even after a perfect scatter correction. In this paper, using a clinical CBCT system and a measurement-based scatter correction, the a...

Journal: :Journal of The Surface Finishing Society of Japan 2020

Journal: :Nihon Hoshasen Gijutsu Gakkai zasshi 2006
Hideki Kato

The anti-scatter grid is generally used as a way of eliminating scattered radiation from X-ray photographs. This does not change even if the detector system changes from an analogue system to a digital system such as the flat-panel detector. We developed a new method that uses software to eliminate scatter components from digital X-ray images taken without the use of an anti-scatter grid. With ...

Journal: :Medical physics 1997
M S Westmore A Fenster I A Cunningham

A new special-purpose computed tomographic (CT) imaging system is described which produces images based on measurements of the low-angle (0-10 degrees) x-ray diffraction properties of an object. Low-angle scatter in the diagnostic x-ray energy range is dominated by coherent scatter, and the system uses first-generation CT geometry to acquire a diffraction pattern for each pencil beam. The patte...

2016
Dongcai Hu Hao Chen Yuan Wang Yunbin Chen Zhou Xu

In the flat panel detector-based cone beam CT system, the scatter photons which reach the flat panel detector increase the detected signal, produce the image cupping artifact and reduce the image contrast. To conquer the X-Ray scatter problem, this study proposes the beam attenuation grid -based scatter correction algorithm that needs to add a beam attenuation grid (BAG) between the X-Ray sourc...

Journal: :Radiology 2005
Ehsan Samei Joseph Y Lo Terry T Yoshizumi Jonathan L Jesneck James T Dobbins Carey E Floyd H Page McAdams Carl E Ravin

PURPOSE To evaluate the scatter, dose, and effective detective quantum efficiency (DQE) performance of a slot-scan digital chest radiography system compared with that of a full-field digital radiography system. MATERIALS AND METHODS Scatter fraction of a slot-scan system was measured for an anthropomorphic and a geometric phantom by using a posterior beam-stop technique at 117 and 140 kVp. Me...

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...

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