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https://www.readbyqxmd.com/read/28086998/evaluation-of-artifacts-generated-by-zirconium-implants-in-cone-beam-computed-tomography-images
#1
Taruska Ventorini Vasconcelos, Boulos B Bechara, Clyde Alex McMahan, Deborah Queiroz Freitas, Marcel Noujeim
OBJECTIVE: To evaluate zirconium implant artifact production in cone beam computed tomography images obtained with different protocols. STUDY DESIGN: One zirconium implant was inserted in an edentulous mandible. Twenty scans were acquired with a ProMax 3D unit (Planmeca Oy, Helsinki, Finland), with acquisition settings ranging from 70 to 90 peak kilovoltage (kVp) and voxel sizes of 0.32 and 0.16 mm. A metal artifact reduction (MAR) tool was activated in half of the scans...
February 2017: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
https://www.readbyqxmd.com/read/28086901/gpu-accelerated-voxel-driven-forward-projection-for-iterative-reconstruction-of-cone-beam-ct
#2
Yi Du, Gongyi Yu, Xincheng Xiang, Xiangang Wang
BACKGROUND: For cone-beam computed tomography (CBCT), which has been playing an important role in clinical applications, iterative reconstruction algorithms are able to provide advantageous image qualities over the classical FDK. However, the computational speed of iterative reconstruction is a notable issue for CBCT, of which the forward projection calculation is one of the most time-consuming components. METHOD AND RESULTS: In this study, the cone-beam forward projection problem using the voxel-driven model is analysed, and a GPU-based acceleration method for CBCT forward projection is proposed with the method rationale and implementation workflow detailed as well...
January 5, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28079527/binary-moving-blocker-based-scatter-correction-in-cone-beam-computed-tomography-with-width-truncated-projections-proof-of-concept
#3
Ho Lee, Benjamin Fahimian, Lei Xing
This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, one-dimensional B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions...
January 12, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28079526/a-measurement-based-generalized-source-model-for-monte-carlo-dose-simulations-of-ct-scans
#4
Xin Ming, Yuanming Feng, Ransheng Liu, Chengwen Yang, Li Zhou, Hezheng Zhai, Jun Deng
The goal of this study is to present a generalized source model (GSM) for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg-Marquardt algorithm...
January 12, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28078367/topographical-relationship-between-positions-of-lingual-foramina-and-attachment-of-mylohyoid-muscle-in-mental-region
#5
Naohiro Morikage, Tomohiro Hamada, Akinobu Usami, Satoshi Takada
PURPOSE: Lingual foramina can be observed between the lingual aspects of the mandible in humans. A sublingual artery is thought to exist in sublingual space and a submental artery in submaxillary space, which pierce the mandible through lingual foramina. During surgery for oral implant placement between apices of the mental foramen, it is important to determine the existence and positioning of lingual foramina. The purpose of this study was to investigate the positions of lingual foramina in relation to the mylohyoid muscle and vertical position of the mylohyoid line using cone-beam computed tomography (CBCT) images...
January 11, 2017: Surgical and Radiologic Anatomy: SRA
https://www.readbyqxmd.com/read/28077902/the-length-of-the-greater-palatine-canal-in-a-lebanese-population-a-radio-anatomical-study
#6
Georges Aoun, Ibrahim Nasseh
OBJECTIVE: The aim of this study was to evaluate the length of the greater palatine canal in a Lebanese population using cone-beam computed tomography (CBCT) technology. MATERIAL AND METHODS: In this study, we measured the length of 148 greater palatine canals in 74 CBCT images of Lebanese adult patients (38 females and 36 males). The data obtained was analyzed statistically to determine 1) if age is related to the length of the canal, 2) if the length of the left side tends to be systematically larger or smaller than the length of the right side, and 3) if the mean length of the canals in females is different than the one in males...
December 2016: Acta Informatica Medica: AIM
https://www.readbyqxmd.com/read/28074785/deformable-registration-of-ct-and-cone-beam-ct-with-local-intensity-matching
#7
Seyoun Park, William Plishker, Harry Quon, John Wong, Raj Shekhar, Junghoon Lee
Cone-beam CT (CBCT) is a widely used intra-operative imaging modality in image-guided radiotherapy and surgery. A short scan followed by a filtered-backprojection is typically used for CBCT reconstruction. While data on the mid-plane (plane of source-detector rotation) is complete, off-mid-planes undergo different information deficiency and the computed reconstructions are approximate. This causes different reconstruction artifacts at off-mid-planes depending on slice locations, and therefore impedes accurate registration between CT and CBCT...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28074591/variations-in-crestal-cortical-bone-thickness-at-dental-implant-sites-in-different-regions-of-the-jawbone
#8
Yi-Chun Ko, Heng-Li Huang, Yen-Wen Shen, Jyun-Yi Cai, Lih-Jyh Fuh, Jui-Ting Hsu
BACKGROUND: Dental implants have become reliable and predictable tools for treating missing teeth. The survival rate of dental implants is markedly influenced by the host bone quality and quantity of the jawbone. A better host bone provides higher initial stability of the dental implant, resulting in better osseointegration and a higher success rate. Host bone quality and quantity are determined by the crestal cortical bone thickness and inner cancellous bone density. OBJECTIVE: The purpose of this study was to determine the crestal cortical bone thickness at dental implant sites in different regions of the jawbone through the use of dental cone-beam computed tomographic (CBCT) images...
January 10, 2017: Clinical Implant Dentistry and related Research
https://www.readbyqxmd.com/read/28074018/evaluation-of-dose-homogeneity-in-cone-beam-breast-computed-tomography
#9
Giovanni Mettivier, Matilde Costa, Nico Lanconelli, Anna Ianiro, Mariagabriella Pugliese, Maria Quarto, Paolo Russo
The aim of this study is to determine, via measurements on phantoms and Monte Carlo (MC) simulations, the dose distribution of absorbed dose in a cone-beam breast computed tomography scan. The absorbed dose volume distribution was measured inside a polyethylene cylindrical phantom, simulating adipose breast tissue, using LiF:Mg,Ti thermoluminescence dosimeters. A reasonable agreement (between 2 and 8%) between the simulated and measured data was observed. The 3D distribution of absorbed dose was evaluated at 40, 60 and 80 kV in a phantom simulating a pendant breast...
January 10, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28072990/-the-images-of-osteoarthrosis-associated-with-anterior-disc-displacement-without-reduction-detected-by-cone-beam-ct
#10
J H Han, J Lei, M Q Liu, K Y Fu
Objective: To analyze the radiological characteristics of the condylar bone in patients with anterior disc displacement without reduction of temporomandibular joint using cone-beam CT (CBCT), and to further investigate the clinical factors possibly associated with the early-stage osteoarthritic changes. Methods: Two hundred and four individuals (≤30 years old) diagnosed as unilateral anterior disc displacement without reduction (disease duration≤1 year) were recruited. CBCT images of bilateral condyles were independently evaluated by two assessors and documented...
January 9, 2017: Zhonghua Kou Qiang Yi Xue za Zhi, Zhonghua Kouqiang Yixue Zazhi, Chinese Journal of Stomatology
https://www.readbyqxmd.com/read/28072395/evaluation-of-adaptive-treatment-planning-for-patients-with-non-small-cell-lung-cancer
#11
Hualiang Zhong, Salim Siddiqui, Benjamin Movsas, Indrin Chetty
The purpose of this study was to develop metrics to evaluate uncertainties in deformable dose accumulation (DDA) for patients with non-small cell lung cancer (NSCLC). Initial treatment plans (primary) and cone-beam CT (CBCT) images were retrospectively processed for seven NSCLC patients, who showed significant tumor regression during the course of treatment. Each plan was developed with IMRT for 2 Gy��33 fractions. A B-spline-based DIR algorithm was used to register weekly CBCT images to a reference image acquired at fraction 21 and the resultant displacement vector fields (DVFs) were then modified using a finite element method (FEM)...
January 10, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28069053/influence-of-daily-imaging-on-plan-quality-and-normal-tissue-toxicity-for-prostate-cancer-radiotherapy
#12
Katharina Bell, Marina Heitfeld, Norbert Licht, Christian Rübe, Yvonne Dzierma
BACKGROUND: Modern radiotherapy offers various possibilities for image guided verification of patient positioning. Different clinically relevant IGRT (image guided radiotherapy) scenarios were considered with regard to their influence on dosimetric plan quality and normal tissue complication probability (NTCP). METHODS: This study is based on treatment plans of 50 prostate patients. We evaluate the clinically performed IGRT and simulate the influence of different daily IGRT scenarios on plan quality...
January 10, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28068573/guidelines-for-reproducing-geometrical-aspects-of-intra-oral-radiographs-images-on-cone-beam-computed-tomography
#13
Janaina Paiva Curi, Thiago Leite Beaini, Ricardo Henrique Alves da Silva, Rodolfo Francisco Haltenhoff Melani, Israel Chilvarquer, Edgard Michel Crosato
Human identification requires comparison of individual traits of a person, depending on the availability and reproduction of antemortem (AM) records. If there is no presumed identity or AM exams are not available for comparison, the production of postmortem (PM) records is impaired. The purpose of this research is to describe and test standards to enable the comparison of antemortem periapical radiographs to images extracted from the manipulation of postmortem CBCT exams in multiple identification simulations in a randomized blind study...
December 22, 2016: Forensic Science International
https://www.readbyqxmd.com/read/28068300/early-postoperative-imaging-of-the-labyrinth-by-cone-beam-ct-after-stapes-surgery-for-otosclerosis-with-correlation-to-audiovestibular-outcome
#14
Aurélie Vandevoorde, Marc T Williams, Elsa Ukkola-Pons, Mary Daval, Denis Ayache
BACKGROUND: Sensorineural complications of stapes surgery are rare but potentially serious. Imaging is usually performed to identify an underlying cause, such as excessive intravestibular penetration of the prosthesis or pneumolabyrinth suggesting perilymphatic fistula. Unfortunately, there is very little data in an unselected series of uneventful patients.The aim of this study was to analyze the depth of prosthesis penetration within the vestibule and the rate of pneumolabyrinth the day or the day after the procedure by performing a cone beam computed tomography of the temporal bone in a cohort of unselected patients, and to correlate imaging findings to clinical outcome...
February 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28066676/image-guided-localization-of-small-lung-nodules-in-video-assisted-thoracic-surgery
#15
REVIEW
Ze-Rui Zhao, Rainbow W H Lau, Peter S Y Yu, Randolph H L Wong, Calvin S H Ng
The advancement of imaging technology has recently facilitated single port minimally-invasive thoracic surgery techniques. Cone-beam computed tomography (CBCT) shows promising results in visualizing the target lesion and its surrounding critical anatomy, with an error of less than 2 mm. The integration of CBCT with the operating room (OR) to form the hybrid OR, provides unparalleled real-time imaging of the patient, which can be used with electromagnetic navigation bronchoscopy to confirm successful navigation and increase procedural accuracy particularly for small peripheral pulmonary targets...
October 2016: Journal of Thoracic Disease
https://www.readbyqxmd.com/read/28065704/alveolar-bone-level-changes-in-maxillary-expansion-treatments-assessed-through-cbct
#16
Vi Pham, Manuel O Lagravère
OBJECTIVES: Determine changes in alveolar bone levels during expansion treatments as assessed through cone-beam computer tomography (CBCT). METHODS: Sixty-one patients from Edmonton, Canada, with maxillary transverse deficiencies were split into three groups. One group was treated with a bone-anchored expander, another group was treated with a tooth-borne maxillary expander (Hyrax) and one group was untreated. CBCTs were obtained from each patient at two time points (initialT1 and at removal of appliance after 6 months T2)...
January 5, 2017: International Orthodontics
https://www.readbyqxmd.com/read/28064031/frequency-of-temporomandibular-osteoarthritis-and-related-symptoms-in-a-hand-osteoarthritis-cohort
#17
Anna-Karin Abrahamsson, Margareth Kristensen, Linda Z Arvidsson, Tore K Kvien, Tore A Larheim, Ida K Haugen
OBJECTIVE: The prevalence of osteoarthritis (OA) in the temporomandibular joints (TMJs) in hand OA patients is largely unknown. Our aims were to explore 1) The frequency of TMJ-related symptoms and clinical findings; 2) The TMJ OA frequency defined by cone beam computed tomography (CBCT); and 3) The relationship between TMJ-related symptoms/clinical findings and CBCT-defined TMJ OA, in a hand OA cohort. METHODS: We calculated the frequencies of TMJ-related symptoms, clinical findings and diagnosis of TMJ OA by CBCT and clinical examination in 54 patients from the Oslo hand OA cohort (88% women, mean (range) age 71 (61-83) years)...
January 4, 2017: Osteoarthritis and Cartilage
https://www.readbyqxmd.com/read/28061010/scatter-correction-using-a-primary-modulator-on-a-clinical-angiography-c-arm-ct-system
#18
Bastian Bier, Martin Berger, Andreas Maier, Marc Kachelrieß, Ludwig Ritschl, Kerstin Műller, Jang-Hwan Choi, Rebecca Fahrig
PURPOSE: Cone-beam computed tomography (CBCT) suffers from a large amount of scatter, resulting in severe scatter artifacts in the reconstructions. Recently, a new scatter correction approach, called improved primary modulator scatter estimation (iPMSE), was introduced. That approach utilizes a primary modulator that is inserted between the X-ray source and the object. This modulation enables estimation of the scatter in the projection domain by optimizing an objective function with respect to the scatter estimate...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28054795/managing-a-lateral-periodontal-cyst-with-bone-graft-a-computed-tomography-assessment-18-months-postoperatively
#19
Rania Livada, Jacob Shiloah, K Mark Anderson, William R Callahan
The lateral periodontal cyst is a rare benign lesion that is generally asymptomatic and commonly discovered by routine intraoral radiography. Reports on proper management of this lesion are readily available. However, the literature is sparse regarding the long-term outcomes following surgery. A traditional radiographic technique does not provide an adequate image of the healing, and a patient may resist the prospect of a reentry procedure. The current report is the first to utilize a cone-beam computed tomography scan to evaluate the healing potential of a freeze-dried bone allograft approximately 18 months postoperatively...
January 2017: Compendium of Continuing Education in Dentistry
https://www.readbyqxmd.com/read/28054399/comparison-of-effects-of-zoledronic-acid-and-clodronate-on-the-bone-structure-imaginological-and-histomorphometrical-study-in-vivo
#20
Stephanie Joana Roman Martelli, Melissa Feres Damian, Ana Paula Neutzling Gomes, André Ribeiro Schinestsck, Alexandre Emídio Ribeiro Silva, Ana Carolina Uchoa Vasconcelos
OBJECTIVES: To compare histologically and imaginologically the bone structure of rats' mandibles treated with bisphosphonates (BPs) and rats that did not receive BPs. METHODS: Thirty-four rat specimens (Rattus novergicus, Wistar strain) were divided in 3 groups: (1) 12 rats treated with zoledronic acid; (2) 12 rats treated with clodronate; and (3) the control group, containing 10 rats that received saline solution. All individuals were exposed to cone beam computed tomography (CBCT)...
January 5, 2017: Journal of Oral Pathology & Medicine
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