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Showing 1 to 20 of 135 for “"Cone Beam"”.
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Geometry of cone-beam reconstruction
… tool we use to unify all existing analytical cone-beam reconstruction methods. These reconstructions are based on formulae derived by Tuy [Tuy, 1983], Smith [Smith, 1985] and Grangeat [Grangeat, 1991] which explicitly link the cone-beam data to some intermediate functions in the Radon …
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Cone Beam Optical Computed Tomography-Based Gel Dosimetry
… accessible, fast optical readout tools such as cone beam optical computed tomography (CT) in combination with stable and reliable low-toxicity gel dosimeters is one key step in this process. In this thesis, the performance capabilities and limitations of the two main classes of cone beam optical …
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Cone-Beam Computed Tomography and Orthodontics: Awareness Assessment
… community's knowledge and understanding of Cone-Beam Computed Tomography (CBCT) technology as well as awareness of the implications of CBCT use, including risk assessment, radiation dose estimation, diagnostic utility, and issues of informed consent. It is incumbent on the profession to …
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Dynamic Cone-beam Reconstruction for Perfusion Computed Tomography
Perfusion CT (Computed Tomography) is a dynamic imaging technique whose aim is to assess the blood supply to tissue. The limited field of view of current CT detectors restricts its use to perfusion studies of a small volume. The introduction of large area detectors in CT, however, will allow …
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Motion binning in cone-beam CT without a prior Model
Cone-beam CT (CBCT), used to reduce setup error in radiotherapy, takes a sequence of about 670 two-dimensional X-rays acquired in a circular arc around the patient over two minutes and reconstructs a three-dimensional volume from these projections. Consequently, when tissues move significantly …
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Applications of cone beam computed tomography in radiotherapy treatment planning.
… capable of 2D planar imaging, fluoroscopy and 3D Cone Beam Computed Tomography (CBCT) imaging. With CBCT imaging, the treatment plan can be modified based on patient’s anatomy just before the treatment session. This method of Adaptive Radiotherapy (ART) helps in managing a patient’s treatment by …
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X-ray Scatter Computation and Simulation in Cone Beam Computed Tomography
In cone beam computed tomography (CBCT) with a large subject volume within the x-ray field, the measured signal can be contaminated by a large amount of scattered photons due to x-ray interactions with the irradiated object. The photon scatter can severely degrade the quality of the reconstructed …
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Optimizing Kilovoltage Cone-Beam Computed Tomography for Image-Guided Radiation Therapy
Kilovoltage cone-beam computed tomography (kV CBCT) has important applications in image guided radiation therapy (IGRT). In its current state, CBCT is suboptimal for these applications due to its considerable radiation dose, poor soft-tissue contrast and inaccurate Hounsfield Units as a result of …
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CONE BEAM COMPUTED TOMOGRAPHY (CBCT) DOSIMETRY: MEASUREMENTS AND MONTE CARLO SIMULATIONS
<p>Cone beam computed tomography (CBCT) is a 3D x-ray imaging technique in which the x-ray beam is transmitted to an object with wide beam geometry producing a 2D image per projection. Due to its faster image acquisition time, wide coverage length per scan, and fewer motion artifacts, the CBCT …
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Cone Beam Computerized Tomography Analysis of Haller cell : Prevalence and Clinical Significance.
<p><strong>Introduction</strong></p> <p>Albert von Haller described Haller cells (HC) as anterior ethmoidal cells along orbital floor and above maxillary sinus ostium. Location of HC could predispose maxillary sinusitis<strong> </strong>(MS)<strong> </strong></p> <p><strong>Purpose of the Study …
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Improving Cone-Beam Computed Tomography Based Adaptive Radiation Therapy with Deep Learning
… patient anatomy. The widespread availability of cone-beam computed tomography (CBCT) and its capability for the 3D imaging of patient anatomy has made CBCT-based ART an emerging and increasingly popular technology in the field of radiation oncology. However, numerous challenges persist in the …
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Factors Influencing Contrast Resolution of Cone Beam CT Using the CB MercuRay
<p><strong>Introduction:</strong> Cone Beam Computed Tomography (CBCT) has an application in all dental specialties. CBCT is an aid in implant dentistry to evaluate anatomical landmarks in both quality and quantity. Hounsfield Unit (HU) values represent a grayscale that is standardized on CT …
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Improvement of image reconstruction speed with GPU in cone beam CT breast imaging
… States. Our group is constructing a dedicated cone beam breast CT (CBCT) system to provide true 3D image to improve the screening and diagnostic of breast cancer. Our result shows that dedicated CBCT out-perform a lot than conventional CT when detecting micro-calcification which is essential to …
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IMAGE-BASED RESPIRATORY MOTION EXTRACTION AND RESPIRATION-CORRELATED CONE BEAM CT (4D-CBCT) RECONSTRUCTION
Accounting for respiration motion during imaging helps improve targeting precision in radiation therapy. Respiratory motion can be a major source of error in determining the position of thoracic and upper abdominal tumor targets during radiotherapy. Thus, extracting respiratory motion is a key task …
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Spatial Resolution Analysis of a Variable Resolution X-ray Cone-beam Computed Tomography System
<p>A new cone-beam computed tomography (CBCT) system is designed and implemented that can adaptively provide high resolution CT images for objects of different sizes. The new system, called Variable Resolution X-ray Cone-beam CT (VRX-CBCT) uses a CsI-based amorphous silicon flat panel detector …
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Development of a Fully Automated Al System for Skeletal Maturity Assessment Using Cone Beam CT
… and cervical vertebrae maturity (CVM) from cone beam computed tomography scans. The total data set consisted of 1200 CBCT scans from orthodontic patients in the Midwest. For SOS, images with indistinct liminal stages were removed, leaving 723 scans remaining. For CVM, scans failing to …
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PREVALENCE & IMPACT OF MAXILLARY SINUS INCIDENTAL FINDINGS IN CONE-BEAM COMPUTERIZED TOMOGRAPHY A SYSTEMATIC REVIEW
Objective: Applications of Cone-beam computerized tomography (CBCT) have increased dramatically in dentistry. Incidental findings (IFs) beyond the area of interest may be encountered. The maxillary sinus incidental findings in CBCT were considered the highest in the literature. This systematic …
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Motion Estimation and Motion-Compensated Reconstruction for Four-Dimensional Cone Beam Computed Tomography (4D-CBCT)
… uncertainty and four dimensional (4D) cone beam computed tomography (CBCT) has been developed to locate tumor in each respiration phase to better estimate the possible motion range of the tumor motion during the treatment. However, 4D-CBCT reconstructed by conventional methods on …
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