نتایج جستجو برای: beam ct

تعداد نتایج: 242842  

Journal: :Japanese Journal of Oral and Maxillofacial Surgery 2016

Journal: :Dentomaxillofacial Radiology 2013

2001
B. M. Carvalho G. T. Herman S. Matej

We report on our first results on the use of Algebraic Reconstruction Techniques (ART) on helical cone-beam Computerized Tomography (CT) data. Two variants of ART have been implemented: a standard one which considers a single ray in an iterative step and a block version which groups several conebeam projections in calculating an iterative update. Both seem to produce high-quality reconstruction...

2009
Sonali Anil Rathore Eric T. Everett Donald Tyndall Abeer Alhadidi Wisam Al-Rawi Angela Broome Jeffery Price Khin Thaw

Background: During the past few decades, changes have been observed not only in the prevalence of dental caries, but also in the distribution and pattern of the disease in the population. Most conventional radiographic imaging of teeth underestimates the presence of caries. Cone-beam CT is a new technology which can provide volumetric data of the object, from which cross-sectional images can be...

Journal: :Medical physics 2012
Daniel Gross Ulrich Heil Ralf Schulze Elmar Schoemer Ulrich Schwanecke

PURPOSE This paper introduces a novel autocalibration method for cone-beam-CTs (CBCT) or flat-panel CTs, assuming a perfect rotation. The method is based on ellipse-fitting. Autocalibration refers to accurate recovery of the geometric alignment of a CBCT device from projection images alone, without any manual measurements. METHODS The authors use test objects containing small arbitrarily posi...

Journal: :Journal of X-ray science and technology 2013
Fenglin Liu Ge Wang Wenxiang Cong Scott S Hsieh Norbert J Pelc

A bowtie is a filter used to shape an x-ray beam and equalize its flux reaching different detector channels. For development of spectral CT with energy discriminating photon-counting (EDPC) detectors, here we propose and evaluate a dynamic bowtie for performance optimization based on a patient model or a scout scan. With a mechanical rotation of a dynamic bowtie and an adaptive adjustment of an...

2016
April A. Brown Allan G. Farman James P. Scheetz

COMPARATIVE LINEAR ACCURACY OF CONE BEAM CT DERIVED 3D IMAGES IN ORTHODONTIC ANALYSIS April A. Brown, BS, D.M.D.

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