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https://www.readbyqxmd.com/read/29143199/cone-beam-ct-in-paediatric-dentistry-dimitra-project-position-statement
#1
REVIEW
Anne Caroline Oenning, Reinhilde Jacobs, Ruben Pauwels, Andreas Stratis, Mihaela Hedesiu, Benjamin Salmon
DIMITRA (dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks) is a European multicenter and multidisciplinary project focused on optimizing cone-beam CT exposures for children and adolescents. With increasing use of cone-beam CT for dentomaxillofacial diagnostics, concern arises regarding radiation risks associated with this imaging modality, especially for children. Research evidence concerning cone-beam CT indications in children remains limited, while reports mention inconsistent recommendations for dose reduction...
November 15, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/29136282/principal-component-reconstruction-pcr-for-cine-cbct-with-motion-learning-from-2d-fluoroscopy
#2
Hao Gao, Yawei Zhang, Lei Ren, Fang-Fang Yin
PURPOSE: This work aims to generate cine CT images (i.e., 4D images with high temporal resolution) based on a novel principal component reconstruction (PCR) technique with motion learning from 2D fluoroscopic training images. METHODS: In the proposed PCR method, the matrix factorization is utilized as an explicit low-rank regularization of 4D images that are represented as a product of spatial principal components and temporal motion coefficients. The key hypothesis of PCR is that temporal coefficients from 4D images can be reasonably approximated by temporal coefficients learned from 2D fluoroscopic training projections...
November 14, 2017: Medical Physics
https://www.readbyqxmd.com/read/29130140/transforaminal-intrathecal-delivery-of-nusinersen-using-cone-beam-computed-tomography-for-children-with-spinal-muscular-atrophy-and-extensive-surgical-instrumentation-early-results-of-technical-success-and-safety
#3
John J Weaver, Niranjana Natarajan, Dennis W W Shaw, Susan D Apkon, Kevin S H Koo, Giri M Shivaram, Eric J Monroe
BACKGROUND: Nusinersen, the only treatment approved by the United States Food and Drug Administration for spinal muscular atrophy (SMA), is delivered intrathecally. Many children with SMA have extensive spinal instrumentation and deformities, often precluding the use of standard approaches for gaining intrathecal access. Furthermore the anatomical distortion that often occurs with rotoscoliosis can complicate the use of fluoroscopic guidance. Compared to fluoroscopy, CT affords superior guidance for complex needle placements...
November 13, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/29125035/cone-beam-computed-tomography-cbct-for-adaptive-image-guided-head-and-neck-radiation-therapy
#4
Christian A Hvid, Ulrik V Elstrøm, Kenneth Jensen, Cai Grau
BACKGROUND: Adaptive (ART) and image guided radiation therapy (IGRT) can improve target coverage and reduce unnecessary irradiation of organs at risk (OAR). The purpose of this study is to report the results of using mid-course imaging and a novel workflow with cone-beam computed tomography (CBCT) surveillance of dose to OAR to trigger adaptive replanning in head and neck radiotherapy. MATERIAL AND METHODS: Impact of radiation therapist (RTT) managed match protocol and mid-course imaging was assessed in two cohorts of consecutive patients receiving RT to the head and neck region, using computed tomography (CT) and CBCT-based dose verification respectively...
November 10, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/29124381/intraprocedural-3d-perfusion-measurement-during-chemoembolisation-with-doxorubicin-eluting-beads-in-liver-metastases-of-malignant-melanoma
#5
Philippe L Pereira, Kristina Krüger, Ernst Hohenstein, Florian Welke, Christof Sommer, Friedegund Meier, Thomas Eigentler, Claus Garbe
OBJECTIVES: To study feasibility and validity of a new software application for intraprocedural assessment of perfusion during chemoembolisation of melanoma metastases. METHODOLOGY: In a prospective phase-II trial, ten melanoma patients with liver-only metastases underwent chemoembolisation with doxorubicin-eluting beads (DEBDOX-TACE). Tumour perfusion was evaluated immediately before and after treatment at cone beam computer tomography (CBCT) using a new software application...
November 9, 2017: European Radiology
https://www.readbyqxmd.com/read/29122361/ventilation-measured-on-clinical-4d-cbct-increased-ventilation-accuracy-through-improved-image-quality
#6
Kasper R Jensen, Carsten Brink, Olfred Hansen, Uffe Bernchou
BACKGROUND AND PURPOSE: Ventilation measured on 4D cone-beam computed tomography (CBCT) using deformable image registration (DIR) may predict specific radiation sensitivity, but the measurement is affected by the current image quality. With 4D computed tomography (CT) measured ventilation acting as a gold standard the current study investigates if image improvements increase the accuracy of 4D-CBCT measured ventilation. MATERIAL AND METHODS: The study consists of 4D-CBCT and 4D-CT scans of 20 non-small-cell lung cancer patients...
November 6, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29121409/image-quality-and-dose-for-a-multi-source-cone-beam-ct-extremity-scanner
#7
Grace Jianan Gang, Wojciech Zbijewski, Mahadevappa Mahesh, Gaurav Thawait, Nathan Packard, John Yorkston, Shadpour Demehri, Jeffrey Harrold Siewerdsen
PURPOSE: This work investigates the dose characteristics and image quality of a multi-source cone-beam CT scanner dedicated for extremity imaging. METHODS: The scanner has an x-ray source with three separate anode-cathode units evenly distributed along the longitudinal direction. A nominal scan protocol fires the three sources sequentially, and a total of 600 projections (200 for each source) are acquired over a source-detector orbit of 210(o) . Dose was measured using a Farmer chamber in three CTDI phantoms stacked end-to-end...
November 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/29119069/targeting-the-tumor-assessing-the-impact-of-bladder-volume-and-position-on-accuracy-of-radiation-delivery-for-patients-with-bladder-cancer
#8
Andrew Kochan, Ryan Rivest, Katie Galloway, Pascal Lambert, Aldrich Ong, Rashmi Koul, Shahida Ahmed, Bashir Bashir, Harvey Quon
Context Daily variations in bladder size and position can negatively impact the ability to accurately deliver radiation. Aims We attempted to quantify how bladder volumes and positions change over the course of radiotherapy for muscle invasive bladder cancer and the planning target volume (PTV) margins required to account for such changes. Methods and material Cone-beam computed tomography (CT) images of 28 patients during their first, second, and third fractions and weekly thereafter were acquired. Bladders were contoured and the volume, centre of mass, and the maximal positions were recorded and compared to the planning CT scan...
September 1, 2017: Curēus
https://www.readbyqxmd.com/read/29116100/the-value-of-cbct-based-tumor-density-and-volume-variations-in-prediction-of-early-response-to-chemoradiation-therapy-in-advanced-nsclc
#9
Qiang Wen, Jian Zhu, Xue Meng, Changsheng Ma, Tong Bai, Xindong Sun, Jinming Yu
The correlations between early responses and the variations in physical density and primary tumor volume (TV) according to cone-beam computed tomography (CBCT) during chemoradiotherapy for non-small cell lung cancer (NSCLC) patients were investigated. 54 patients with inoperable and locally advanced NSCLC were included in this study. The CT numbers (CTN) and TV were measured on each of the seven observation points. The changes in the mean CTN values and the variation ratios of TV during the treatment course were analysed and correlated with the clinical outcomes, as evaluated by the RECIST criteria...
November 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29116058/a-line-fiducial-method-for-geometric-calibration-of-cone-beam-ct-systems-with-diverse-scan-trajectories
#10
Matthew W Jacobson, Michael Daniel Ketcha, Sarah Capostagno, Alexander Martin, Ali Uneri, Joseph Goerres, Tharindu De Silva, Sureerat Reaungamornrat, Runze Han, Amir Manbachi, Joseph Webster Stayman, Sebastian Vogt, Gerhard Kleinszig, Jeffrey H Siewerdsen
Modern cone-beam CT systems, especially C-arms, are capable of diverse source-detector orbits. However, geometric calibration of these systems using conventional configurations of spherical fiducials (BBs) may be challenged for novel source-detector orbits and system geometries. In part, this is because the BB configurations are designed with careful forethought regarding the intended orbit so that BB marker projections do not overlap in projection views. Examples include helical arrangements of BBs (Rougee et al Proc...
November 8, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29116054/non-rigid-ct-cbct-to-cbct-registration-for-online-external-beam-radiotherapy-guidance
#11
Cornel Zachiu, Baudouin Denis de Senneville, Rob H N Tijssen, Alexis N T J Kotte, Antonetta Christina Houweling, Linda G W Kerkmeijer, Jan J W Lagendijk, Chrit T W Moonen, Mario G Ries
Image-guided external beam radiotherapy (EBRT) allows radiation dose deposition with a high degree of accuracy and precision. Guidance is usually achieved by estimating the displacements, via image registration, between cone beam computed tomography (CBCT) and computed tomography (CT) images acquired at different stages of the therapy. The resulting displacements are then used to reposition the patient such that the location of the tumor at the time of treatment matches its position during planning. Moreover, ongoing research aims to use CBCT-CT image registration for online plan adaptation...
November 8, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29114618/orthogonal-image-pairs-coupled-with-osms-for-noncoplanar-beam-angle-intracranial-single-isocenter-srs-treatments-with-multiple-targets-on-the-varian-edge-radiosurgery-system
#12
Jasmine A Oliver, Patrick Kelly, Sanford L Meeks, Twyla R Willoughby, Amish P Shah
Purpose: To characterize the accuracy of noncoplanar image guided radiation therapy with the Varian Edge radiosurgery system for intracranial stereotactic radiosurgery (SRS) treatments by assessing the accuracy of kV/kV orthogonal pair registration with Optical Surface Monitoring System (OSMS) monitoring relative to cone beam computed tomography (CT). Methods and materials: A Computerized Imaging Reference System head phantom and Encompass SRS Immobilization System were used to determine collision-free space for orthogonal image pairs (kV/kV) for couch rotations (CRs) of 45°, 30°, 15°, 345°, 330°, and 315°...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29114611/2d-kv-orthogonal-imaging-with-fiducial-markers-is-more-precise-for-daily-image-guided-alignments-than-soft-tissue-cone-beam-computed-tomography-for-prostate-radiation-therapy
#13
Peter H Goff, Louis B Harrison, Eli Furhang, Evan Ng, Stephen Bhatia, Frieda Trichter, Ronald D Ennis
Purpose: The hypothesis is that 2-dimensional kV orthogonal imaging with fiducial markers (kV-FM) and soft-tissue cone beam computed tomography (ST-CBCT) are equally reproducible for daily positional alignments for image guided (IG) intensity modulated radiation therapy (IMRT) for prostate cancer. Methods and materials: Ten patients undergoing definitive treatment for prostate cancer with IG-IMRT were imaged daily with kV-FM and ST-CBCT. For each acquired kV and CBCT image, offline alignments to the digitally reconstructed radiograph or planning CT, respectively, were made twice by the same physician to assess intraobserver test-retest reproducibility...
July 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/29108751/three-dimensional-reconstructions-of-ct-scans-and-cone-beam-ct-of-impacted-maxillary-canines-in-order-to-locate-areas-of-ankylosis-before-orthodontic-traction
#14
Florian Plaisance, Jean-Baptiste Kerbrat, Patrick Goudot
PURPOSE: The aim of this study was to model impacted maxillary canines and determine whether areas of ankylosis were present before undertaking orthodontic traction. MATERIAL AND METHODS: Amira/ResolveRT™ software, version 5.0, by FEI Company is a meshing and surface-rendering program that was used to produce three-dimensional reconstructions from CT scans and cone beam images of the impacted canines of 30 patients (10 cone beam files and 20 CT scan files). RESULTS AND DISCUSSION: The presence of zones of ankylosis on the roots of certain impacted canines is revealed by the inversion of the direction of meshing on the tooth surface and on a larger scale by invagination of bone tissue into the tooth tissue at various densities measured in Hounsfield units by the AMIRA™ software program...
November 3, 2017: International Orthodontics
https://www.readbyqxmd.com/read/29102968/delayed-ischemic-stroke-due-to-stent-marker-band-occlusion-after-stent-assisted-coiling
#15
Shuhei Kawabata, Hirotoshi Imamura, Keita Suzuki, Shoichi Tani, Hidemitsu Adachi, Nobuyuki Sakai
A middle-aged patient with an internal carotid-posterior communicating artery aneurysm and basilar artery tip aneurysm was treated by stent-assisted coiling. One ischemic infarction and two transient ischemic attacks occurred with the same symptoms (inability to walk unassisted and tendency to fall to the left) during the first 2 years post-treatment. The ischemic infarction was found in the right side of the pons, consistent with the vascular territory of the stent-containing vessel. The cause of the delayed ischemic stroke was investigated on DSA and cone beam CT, which revealed that the proximal end of the stent, one marker band, was just covering a small perforating artery of the basilar artery trunk...
November 3, 2017: BMJ Case Reports
https://www.readbyqxmd.com/read/29100788/deep-inspiration-breath-hold-intensity-modulated-radiation-therapy-to-the-mediastinum-for-lymphoma-patients-setup-uncertainties-and-margins
#16
Michalis Aristophanous, Pai-Chun M Chi, Jeremy Kao, Ryan Williamson, Sam Tung, Therese Andraos, Sarah A Milgrom, Chelsea C Pinnix, Bouthaina S Dabaja
PURPOSE: Patient setup for treating large target volumes can be challenging. In the present study, we measured the local uncertainties in the treatment of mediastinal lymphoma and investigated the need for region-specific planning target volume (PTV) margins. METHODS AND MATERIALS: The data from 30 patients who had undergone radiation therapy for mediastinal lymphoma were retrospectively analyzed. A computed tomography (CT)-on-rails (CTOR) system in the treatment room was used for daily image guidance...
September 25, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29095489/modeling-and-evaluation-of-a-high-resolution-cmos-detector-for-cone-beam-ct-of-the-extremities
#17
Qian Cao, Alejandro Sisniega, Michael Brehler, J Webster Stayman, John Yorkston, Jeffrey H Siewerdsen, Wojciech Zbijewski
PURPOSE: Quantitative assessment of trabecular bone microarchitecture in extremity cone-beam CT (CBCT) would benefit from the high spatial resolution, low electronic noise, and fast scan time provided by complementary metal-oxide semiconductor (CMOS) x-ray detectors. We investigate the performance of CMOS sensors in extremity CBCT, in particular with respect to potential advantages of thin (<0.7 mm) scintillators offering higher spatial resolution. METHODS: A cascaded systems model of a CMOS x-ray detector incorporating the effects of CsI:Tl scintillator thickness was developed...
November 2, 2017: Medical Physics
https://www.readbyqxmd.com/read/29094053/measurement-of-tibial-tuberosity-trochlear-groove-offset-distance-by-weightbearing-cone-beam-computed-tomography-scan
#18
John M Marzo, Melissa A Kluczynski, Anthony Notino, Leslie J Bisson
Background: Computed tomography (CT) scans are useful for objectively measuring bone alignment because they show bone detail particularly well, and these scans have been used extensively to assess patellar orientation. The tibial tubercle-trochlear groove (TT-TG) offset distance has been shown to be influenced by knee flexion and weightbearing, yet conventional CT scans are obtained with the subject relaxed, supine, and with the knee in full extension. A new cone-beam CT scanner has been designed to allow for weightbearing images, potentially providing a more physiologically relevant assessment of patellofemoral alignment...
October 2017: Orthopaedic Journal of Sports Medicine
https://www.readbyqxmd.com/read/29091472/evidence-of-genotoxicity-and-cytotoxicity-of-x-rays-in-the-oral-mucosa-epithelium-of-adults-subjected-to-cone-beam-computed-tomography
#19
Juliana Bm da Fonte, Tais M de Andrade, Ricardo Lc Albuquerque-Júnior, Maria de Fátima B de Melo, Wilton M Takeshita
OBJECTIVES: To assess cytological evidence of genotoxicity and cytotoxicity of X-rays in oral exfoliated cells of adults subjected to partial and total CBCT (stitching module) by means of micronuclei frequency, associated with counting of degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis, buds and broken eggs), besides comparing the partial and total CBCT (stitching module) in search of possible differences in the nature and/or intensity of the effects. METHODS: Twenty-nine adults who were referred to total or partial CBCT were selected...
November 1, 2017: Dento Maxillo Facial Radiology
https://www.readbyqxmd.com/read/29077573/shading-correction-assisted-iterative-cone-beam-ct-reconstruction
#20
Chunlin Yang, Pengwei Wu, Shutao Gong, Jing Wang, Qihui Lyu, Xiangyang Tang, Tianye Niu
Recent advances in total variation (TV) technology enable accurate CT image reconstruction from highly under-sampled and noisy projection data. The standard iterative reconstruction algorithms, which work well in conventional CT imaging, fail to perform as expected in cone beam CT (CBCT) applications, wherein the non-ideal physics issues, including scatter and beam hardening, are more severe. These physics issues result in large areas of shading artifacts and cause deterioration to the piecewise constant property assumed in reconstructed images...
October 27, 2017: Physics in Medicine and Biology
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