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Artifact analysis of approximate helical cone-beam CT reconstruction algorithms

Th. Köhler, R. Proksa, C. Bontus, M. Grass, J. Timmer
2001 Medical Physics (Lancaster)  
It is shown that the use of redundant data in the 3-PI method suppresses aliasing artifacts efficiently for both scanners.  ...  For a detector with isotropic resolution of 0.5 mm, we found that ASSR and PI produce different kinds of artifacts which are almost at the same level, while PI-SLANT produces none of these artifacts.  ...  To calculate the in-plane PSF, the average in the z-direction was calculated to remove helical artifacts which are present due to the asymmetry induced by the quarter detector offset.  ... 
doi:10.1118/1.1413518 pmid:11831573 fatcat:7nbopw4z4rbuxpadrlcd2kg5d4

Super-resolution imaging in a multiple layer EPID

Haijian Chen, Joerg Rottmann, Stephen SF Yip, Daniel Morf, Rony Füglistaller, Josh Star-Lack, George Zentai, Ross Berbeco
2017 Biomedical engineering and physics express  
A 6 MV beam is attenuated through each phantom and detected by each of the four detector layers. Fill factor of the detector is explicitly considered.  ...  For measuring CNR in MV-CBCT, a 20 cm diameter digital phantom with 8 inserts of different electron densities is used.  ...  The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.  ... 
doi:10.1088/2057-1976/aa5d20 pmid:28713589 pmcid:PMC5507372 fatcat:7gleu6u4pjh4hhhm2mtv3rrzly

What is Cone-Beam CT and How Does it Work?

William C. Scarfe, Allan G. Farman
2008 Dental Clinics of North America  
A reduced data sample leads to misregistration and sharp edges and noisier images because of aliasing, where fine striations appear in the image.  ...  Advantages of cone-beam CT in dentistry Being considerably smaller, CBCT equipment has a greatly reduced physical footprint and is approximately one quarter to one fifth the cost of conventional CT.  ... 
doi:10.1016/j.cden.2008.05.005 pmid:18805225 fatcat:6p3o4ujkevaajesgert66qyhiu

High Fidelity System Modeling for High Quality Image Reconstruction in Clinical CT

Synho Do, William Clem Karl, Sarabjeet Singh, Mannudeep Kalra, Tom Brady, Ellie Shin, Homer Pien, Arrate Muñoz-Barrutia
2014 PLoS ONE  
Lastly, we compared images of low-dose in vivo data using Filtered-Back-Projection, Iterative Reconstruction in Image Space, and the proposed method using raw data.  ...  We first isolated the fidelity term and analyzed the importance of using focal spot area modeling, flying focal spot location modeling, and active detector area modeling as opposed to just flying focal  ...  Karl Stierstofer, Christianne Leidecker, and Dr. Thomas G. Flohr (Siemens Healthcare) for providing system geometry and data structure information of CT sinogram. Author Contributions  ... 
doi:10.1371/journal.pone.0111625 pmid:25390888 pmcid:PMC4229099 fatcat:ws2swmteprcfdn4cxmhpvczdmq

Technical development in cardiac CT: current standards and future improvements—a narrative review

Patrizia Toia, Ludovico La Grutta, Giulia Sollami, Alberto Clemente, Cesare Gagliardo, Massimo Galia, Erica Maffei, Massimo Midiri, Filippo Cademartiri
2020 Cardiovascular Diagnosis and Therapy  
Technological development together with improvements in spatial, temporal, and contrast resolution, progressively allowed implementation of the current clinical role of the CT assessment of coronary arteries  ...  In this review, we will discuss current standards and future improvements in CCT.  ...  The quarter detector offset is used to reduce aliasing artifacts (19) .  ... 
doi:10.21037/cdt-20-527 pmid:33381441 pmcid:PMC7758763 fatcat:4ekhc7de7rb6nip26wpk52f3rq

A combined local and global motion estimation and compensation method for cardiac CT

Qiulin Tang, Beshan Chiang, Akinola Akinyemi, Alexander Zamyatin, Bibo Shi, Satoru Nakanishi, Bruce R. Whiting, Christoph Hoeschen
2014 Medical Imaging 2014: Physics of Medical Imaging  
between dose, noise and view weighting functions of different reconstruction algorithms in CT helical scans.  ...  We have used a device composed of a laser and detectors for measuring the optical reflectance of unit samples.  ...  This is a manual process and can be time consuming in cases where several sections using different stains are required.  ... 
doi:10.1117/12.2043492 fatcat:fyzpc5m6jbh7fjohqpdmtzkhte

Geometrical Calibration and Filter Optimization for Cone-Beam Computed Tomography

Jens Muders
2015
Especially for helical CBCT (H-CBCT), this fact suggests that a precise calibration of the computed tomography (CT) system is inevitable.  ...  providing accessibility and extendability through to use of a scripting language environment.  ...  the volume and accumulate the samples Figure 3 . 6 : 36 Comparison of different choices for the horizontal detector offset during helical reconstruction from real data.  ... 
doi:10.11588/heidok.00018625 fatcat:vbx6eyt7g5cslbvch7dz5mocuu

PIC methods in astrophysics: Simulations of relativistic jets and kinetic physics in astrophysical systems [article]

Kenichi Nishikawa, Ioana Dutan, Christoph Köhn, Yosuke Mizuno
2021 arXiv   pre-print
Finally, we give an outlook of the future simulations of jets associated to neutron stars, black holes and their merging and discuss the future of PIC simulations in the light of petascale and exascale  ...  Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently  ...  Simulations were performed using Pleiades and Endeavor facilities at NASA Advanced Supercomputing (NAS: s2004), using Comet at The San Diego Supercomputer Center (SDSC), Bridges at The Pittsburgh Supercomputing  ... 
arXiv:2008.02105v3 fatcat:5uttdaqnrjekbemtgaxwliafua

Optical Tweezers: A Comprehensive Tutorial from Calibration to Applications [article]

Jan Gieseler, Juan Ruben Gomez-Solano, Alessandro Magazzù, Isaac Pérez Castillo, Laura Pérez García, Marta Gironella-Torrent, Xavier Viader-Godoy, Felix Ritort, Giuseppe Pesce, Alejandro V. Arzola, Karen Volke-Sepulveda, Giovanni Volpe
2020 arXiv   pre-print
In this Tutorial, we provide a primer on how to calibrate optical tweezers and how to use them for advanced applications.  ...  Since their invention in 1986 by Arthur Ashkin and colleagues, optical tweezers have become an essential tool in several fields of physics, spectroscopy, biology, nanotechnology, and thermodynamics.  ...  We thank Erik Hebestreit, Vijay Jain, Martin Frimmer, Felix Tebbenjohanns, Francesco Ricci for providing us with data and feedback and the Quidant and Novotny groups for stimulating discussions.  ... 
arXiv:2004.05246v1 fatcat:gutmiittwvck7cr2smdt3ni7by

Three-dimensional point-cloud room model in room acoustics simulations

Milos Markovic, So/ren K. Olesen, Dorte Hammersho/i
2013 Journal of the Acoustical Society of America  
of signal that can be sampled without aliasing.  ...  Superposition of signals from an appropriately positioned four-element receiver array gives a helicity selective detector and commutation of diagonal source elements can be used to reverse the source helicity  ...  In particular, environmental parameters are treated using Metropolis-Hastings sampling applied efficiently in a principal-component space, and source locations are treated using Gibbs sampling since the  ... 
doi:10.1121/1.4806371 fatcat:ln4w6j7cjvchrckf2gzfmeiwoi

SPR 2020

2020 Pediatric Radiology  
and consequences for both of these rare issues.  ...  Methods & Materials: Materialise Mimics TM was used with chest CT data of one infant to segment the air contained in the airway, which was wrapped in a 2mm offset to create a lumen model.  ...  Ultrasound (US) imaging was available for 89 lesions, CT in 50 lesions and MRI of lesions. pFNH are iso-/hyperechoic on US in 82.8% (72/87) with arterial Doppler flow in 74% (37/50).  ... 
doi:10.1007/s00247-020-04679-0 pmid:32435980 fatcat:y6da6d4blvaxlkus6w6zahpwlu

Radio interferometry techniques for geodesy

1979 Bulletin Géodésique  
Correlation and further processing of the data is carried out, for the most part, using the threestation Mark II processor at the Max Planck Institut fiir Radioastronomie in Bonn, Germany.  ...  A smoothly The success of the NASA developments of VLBI and space laser ranging has prompted NASA to establish a Crustal Dynamics Project for the application of these space techniques to the study of the  ...  Over sampling the data produces correlation between samples and increases the noise level while undersampling reduces the signal by aliasing.  ... 
doi:10.1007/bf02521643 fatcat:2wf6omvyrfeb7iq56xseifrpxe

Discrimination of short speech‐like formant transitions

Astrid van Wieringen, Louis C. W. Pols
1992 Journal of the Acoustical Society of America  
Results are presented concerning the salience of co-modulation, harmonicity, onset and offset cues, and amplitude spectrum with respect to auditory sources using the new tool.  ...  Consequently, the shock waves are not always well focused on the stone, which results in an increase of the duration of the treatment and the development of lesions in the neighboring tissues.  ...  is sufficient to prevent aliasing in both the data and the discrete-time autocorrelation calculated from the data of a bandlimited energy signal, the sampling requirements for the avoidance of aliasing  ... 
doi:10.1121/1.405128 fatcat:dbtewzqvijhkta6op7ul3ribti

Multi-modal image fusion during minimally invasive treatment [article]

Ruijters, DSA (Daniel), Haar Romeny, BM (Bart) Ter, Suetens, P (Paul)
2010
They suggest using an RGB texture, consisting of 128 samples of 16-bit accuracy, and using linear filtering between the samples.  ...  As a consequence, the image-based registration of the CT and peri-operative cone-beam CT datasets also registers the CT and C-arm coordinate systems, see section 6.6.  ...  In the biomedical arena multiple coordinate spaces are encountered when dealing with multi-modal image registration and fusion, but also when considering the mechanical parts of an imaging system, or when  ... 
doi:10.6100/ir668391 fatcat:vtwrxdlsifbqrm2e32vi5n5e3u

Predicting room acoustical behavior with the ODEON computer model

Graham Naylor, Jens Holger Rindel
1992 Journal of the Acoustical Society of America  
Results are presented concerning the salience of co-modulation, harmonicity, onset and offset cues, and amplitude spectrum with respect to auditory sources using the new tool.  ...  Consequently, the shock waves are not always well focused on the stone, which results in an increase of the duration of the treatment and the development of lesions in the neighboring tissues.  ...  is sufficient to prevent aliasing in both the data and the discrete-time autocorrelation calculated from the data of a bandlimited energy signal, the sampling requirements for the avoidance of aliasing  ... 
doi:10.1121/1.404931 fatcat:z4hbezklfzgu7hyy7qvos3wyo4
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