Results 291 to 300 of about 177,511 (317)
Some of the next articles are maybe not open access.
Image artifact in dental cone-beam CT
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006The purpose of this study was to investigate the appearance and possible cause of an artifact seen in limited-volume cone-beam CT imaging.A water-filled plastic cylinder was used as a phantom of the head. A test object was constructed as a bone-equivalent phantom to be imaged.
Akitoshi, Katsumata +7 more
openaire +2 more sources
Auto calibration of a cone‐beam‐CT
Medical Physics, 2012Purpose: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 ...
Daniel, Gross +4 more
openaire +2 more sources
Dose calculation using megavoltage cone-beam CT
International Journal of Radiation Oncology*Biology*Physics, 2007To demonstrate the feasibility of performing dose calculation on megavoltage cone-beam CT (MVCBCT) of head-and-neck patients in order to track the dosimetric errors produced by anatomic changes.A simple geometric model was developed using a head-size water cylinder to correct an observed cupping artifact occurring with MVCBCT.
Olivier, Morin +9 more
openaire +2 more sources
Quantitative cone beam megavoltage CT
2000In recent years there has been increasing interest in cone beam megavoltage CT (MVCT) using the photon beam of a treatment machine and an electronic portal imaging device (EPID), see e. g. [1]. So far this technique has been investigated with respect to its potential in patient set-up control, which requires high contrast and adequate spatial ...
L. Spies +4 more
openaire +1 more source
Cone-beam CT from width-truncated projections
Computerized Medical Imaging and Graphics, 1996In this paper we report cone-beam CT techniques that permit reconstruction from width-truncated projections. These techniques are variants of Feldkamp's filtered backprojection algorithm and assume quasi-redundancy of ray integrals. Two methods are derived and compared. The first method involves the use of preconvolution weighting of the truncated data.
P S, Cho, A D, Rudd, R H, Johnson
openaire +2 more sources
Actively triggered 4d cone‐beam CT acquisition
Medical Physics, 2013Purpose:4d cone‐beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this “after‐the‐fact” binning approach, however, projections are unevenly distributed over respiratory ...
Martin F, Fast +3 more
openaire +2 more sources
Spiral Cone-Beam CT Reconstruction
2017This image describes the CT image of the phantom which has been captured by the CT machine, and this image is given as the input to the next processes for the generation of the sinogram image and for the process of the back projection.
Vinit Kumar Gunjan +3 more
openaire +1 more source
2015
So far, this book has focused on the detector configuration in which a single row of a detector is irradiated by the x-ray beam. Although helical (spiral) CT has significantly improved volume coverage, many clinical applications demand an even greater volume coverage and thinner slices. A good example is CT angiography.
openaire +1 more source
So far, this book has focused on the detector configuration in which a single row of a detector is irradiated by the x-ray beam. Although helical (spiral) CT has significantly improved volume coverage, many clinical applications demand an even greater volume coverage and thinner slices. A good example is CT angiography.
openaire +1 more source
What is cone-beam CT and how does it work?
Dental Clinics of North America, 2008W. Scarfe, A. Farman
semanticscholar +1 more source
Cone-beam CT in paediatric dentistry: DIMITRA project position statement
Pediatric Radiology, 2018A. Oenning +6 more
semanticscholar +1 more source