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https://www.readbyqxmd.com/read/27910717/dose-optimisation-for-assessment-of-periodontal-structures-in-cone-beam-ct-examinations
#1
Ayman Al-Okshi, Chrysoula Theodorakou, Christina Lindh
OBJECTIVE: To investigate the relationship between dose and image quality for a dedicated dental Cone Beam CT (CBCT) scanner using different scanning protocols and to set up an optimal imaging protocol for assessment of periodontal structures. METHODS: Radiation dose and image quality measurements were made using the 3D Accuitomo 170 dental CBCT scanner. The SedentexCT IQ phantom was used to investigate the relationship between contrast-to-noise ratio (CNR) and dose-area product (DAP)...
December 2, 2016: Dento Maxillo Facial Radiology
https://www.readbyqxmd.com/read/27895964/half-fan-based-intensity-weighted-region-of-interest-imaging-for-low-dose-cone-beam-ct-in-image-guided-radiation-therapy
#2
Boyeol Yoo, Kihong Son, Rizza Pua, Jinsung Kim, Alexander Solodov, Seungryong Cho
OBJECTIVES: With the increased use of computed tomography (CT) in clinics, dose reduction is the most important feature people seek when considering new CT techniques or applications. We developed an intensity-weighted region-of-interest (IWROI) imaging method in an exact half-fan geometry to reduce the imaging radiation dose to patients in cone-beam CT (CBCT) for image-guided radiation therapy (IGRT). While dose reduction is highly desirable, preserving the high-quality images of the ROI is also important for target localization in IGRT...
October 2016: Healthcare Informatics Research
https://www.readbyqxmd.com/read/27895878/evaluation-of-visibility-of-foreign-bodies-in-the-maxillofacial-region-comparison-of-computed-tomography-cone-beam-computed-tomography-ultrasound-and-magnetic-resonance-imaging
#3
Solmaz Valizadeh, Hamidreza Pouraliakbar, Leila Kiani, Yaser Safi, Leila Alibakhshi
BACKGROUND: Detection of foreign bodies (FBs) is challenging. Selection of a fast and affordable imaging modality to locate the FB with minimal patient radiation dose is imperative. OBJECTIVES: This study sought to compare four commonly used imaging modalities namely cone beam computed tomography (CBCT), magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound (US) for detection of FBs in the head and neck region. MATERIALS AND METHODS: In this in vitro study, iron, glass, stone, wood, asphalt, and tooth samples measuring 0...
October 2016: Iranian Journal of Radiology: a Quarterly Journal Published By the Iranian Radiological Society
https://www.readbyqxmd.com/read/27894729/effect-of-diagnostic-cone-beam-computed-tomography-protocols-on-image-quality-patient-dose-and-lesion-detection
#4
Jijo Paul, Annamma Chacko, Paola Saccomandi, Thomas J Vogl, Nour-Eldin A Nour-Eldin
OBJECTIVE: To evaluate the effect of cone-beam computed tomography (CBCT) image acquisition protocols on image quality, lesion detection, delineation, and patient dose. METHODS: 100-patients and a CTDI phantom combined with an electron density phantom were examined using four different CBCT-image acquisition protocols during image-guided transarterial chemoembolization (TACE). Protocol-1 (time: 6s, tube rotation: 360°), protocol-2 (5s, 300°), protocol-3 (4s, 240°) and protocol-4 (3s, 180°) were used...
November 25, 2016: Physica Medica: PM
https://www.readbyqxmd.com/read/27881158/evaluation-of-daily-patient-positioning-for-radiotherapy-with-a-commercial-3d-surface-imaging-system-catalyst%C3%A2
#5
F Walter, P Freislederer, C Belka, C Heinz, M Söhn, F Roeder
BACKGROUND: To report our initial clinical experience with the novel surface imaging system Catalyst™ (C-RAD AB, Sweden) in connection with an Elekta Synergy linear accelerator for daily patient positioning in patients undergoing radiation therapy. METHODS: We retrospectively analyzed the patient positioning of 154 fractions in 25 patients applied to thoracic, abdominal, and pelvic body regions. Patients were routinely positioned based on skin marks, shifted to the calculated isocenter position and treated after correction via cone beam CT which served as gold standard...
November 24, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27869556/evaluation-of-on-and-off-line-bioluminescence-tomography-system-for-focal-irradiation-guidance
#6
Bin Zhang, John W Wong, Iulian I Iordachita, Juvenal Reyes, Katriana Nugent, Phuoc T Tran, Stephen W Tuttle, Constantinos Koumenis, Ken Kang-Hsin Wang
In response to the limitations of computed tomography (CT) and cone-beam CT (CBCT) in irradiation guidance, especially for soft-tissue targets without the use of contrast agents, our group developed a solution that implemented bioluminescence tomography (BLT) as the image-guidance modality for preclinical radiation research. However, adding such a system to existing small animal irradiators is no small task. A potential solution is to utilize an off-line BLT system in close proximity to the irradiator, with stable and effective animal transport between the two systems...
November 21, 2016: Radiation Research
https://www.readbyqxmd.com/read/27866848/analysis-of-gtv-reduction-during-radiotherapy-for-oropharyngeal-cancer-implications-for-adaptive-radiotherapy
#7
Olga Hamming-Vrieze, Simon R van Kranen, Wilma D Heemsbergen, Charlotte A H Lange, Michiel W M van den Brekel, Marcel Verheij, Coen R N Rasch, Jan Jakob Sonke
BACKGROUND AND PURPOSE: Adaptive field size reduction based on gross tumor volume (GTV) shrinkage imposes risk on coverage. Fiducial markers were used as surrogate for behavior of tissue surrounding the GTV edge to assess this risk by evaluating if GTVs during treatment are dissolving or actually shrinking. MATERIALS AND METHODS: Eight patients with oropharyngeal tumors treated with chemo-radiation were included. Before treatment, fiducial markers (0.035×0.2cm(2), n=40) were implanted at the edge of the primary tumor...
November 18, 2016: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/27853499/effect-of-voxel-size-on-detection-of-external-root-resorption-defects-using-cone-beam-computed-tomography
#8
Sima Nikneshan, Solmaz Valizadeh, Anahita Javanmard, Leila Alibakhshi
BACKGROUND: Selecting a voxel size that yields minimal radiation dose with no significant compromise of the diagnostic accuracy of cone beam computed tomography (CBCT) is particularly important. OBJECTIVES: This study aimed to assess the effect of voxel size on detection accuracy of simulated external root resorption defects using NewTom CBCT system. MATERIALS AND METHODS: In this diagnostic study, the roots of 90 extracted human central incisors were hypothetically divided into cervical, middle, and apical thirds...
July 2016: Iranian Journal of Radiology: a Quarterly Journal Published By the Iranian Radiological Society
https://www.readbyqxmd.com/read/27825386/initial-results-for-patient-setup-verification-using-transperineal-ultrasound-and-cone-beam-ct-in-external-beam-radiation-therapy-of-prostate-cancer
#9
Anne Richter, Bülent Polat, Ingulf Lawrenz, Stefan Weick, Otto Sauer, Michael Flentje, Frederick Mantel
BACKGROUND: Evaluation of set up error detection by a transperineal ultrasound in comparison with a cone beam CT (CBCT) based system in external beam radiation therapy (EBRT) of prostate cancer. METHODS: Setup verification was performed with transperineal ultrasound (TPUS) and CBCT for 10 patients treated with EBRT for prostate cancer. In total, 150 ultrasound and CBCT scans were acquired in rapid succession and analyzed for setup errors. The deviation between setup errors of the two modalities was evaluated separately for each dimension...
November 8, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27806588/source-modeling-for-monte-carlo-dose-calculation-of-ct-examinations-with-a-radiotherapy-treatment-planning-system
#10
Hans-Erik Källman, Rickard Holmberg, Jonas Andersson, Love Kull, Erik Tranéus, Anders Ahnesjö
PURPOSE: Radiation dose to patients undergoing examinations with Multislice Computed Tomography (MSCT) as well as Cone Beam Computed Tomography (CBCT) is a matter of concern. Risk management could benefit from efficient replace rational dose calculation tools. The paper aims to verify MSCT dose calculations using a Treatment Planning System (TPS) for radiotherapy and to evaluate four different variations of bow-tie filter characterizations for the beam model used in the dose calculations...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27804280/cone-beam-computed-tomography-for-lung-cancer-validation-with-ct-and-monitoring-tumour-response-during-chemo-radiation-therapy
#11
Alissa Michienzi, Tomas Kron, Jason Callahan, Nikki Plumridge, David Ball, Sarah Everitt
INTRODUCTION: Cone-beam computed tomography (CBCT) is a valuable image-guidance tool in radiation therapy (RT). This study was initiated to assess the accuracy of CBCT for quantifying non-small cell lung cancer (NSCLC) tumour volumes compared to the anatomical 'gold standard', CT. Tumour regression or progression on CBCT was also analysed. METHODS: Patients with Stage I-III NSCLC, prescribed 60 Gy in 30 fractions RT with concurrent platinum-based chemotherapy, routine CBCT and enrolled in a prospective study of serial PET/CT (baseline, weeks two and four) were eligible...
November 2, 2016: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/27788959/observer-evaluation-of-a-metal-artifact-reduction-algorithm-applied-to-head-and-neck-cone-beam-computed-tomographic-images
#12
Mark Korpics, Murat Surucu, Ibrahim Mescioglu, Fiori Alite, Alec M Block, Mehee Choi, Bahman Emami, Matthew M Harkenrider, Abhishek A Solanki, John C Roeske
PURPOSE AND OBJECTIVES: To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer. METHODS AND MATERIALS: An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants...
November 15, 2016: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/27788953/prospective-validation-of-a-high-dimensional-shape-model-for-organ-motion-in-intact-cervical-cancer
#13
Casey W Williamson, Garrett Green, Sonal S Noticewala, Nan Li, Hanjie Shen, Florin Vaida, Loren K Mell
PURPOSE: Validated models are needed to justify strategies to define planning target volumes (PTVs) for intact cervical cancer used in clinical practice. Our objective was to independently validate a previously published shape model, using data collected prospectively from clinical trials. METHODS AND MATERIALS: We analyzed 42 patients with intact cervical cancer treated with daily fractionated pelvic intensity modulated radiation therapy and concurrent chemotherapy in one of 2 prospective clinical trials...
November 15, 2016: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/27788215/comparison-of-diagnostic-accuracy-of-radiation-dose-equivalent-radiography-multidetector-computed-tomography-and-cone-beam-computed-tomography-for-fractures-of-adult-cadaveric-wrists
#14
Jakob Neubauer, Matthias Benndorf, Carolin Reidelbach, Tobias Krauß, Florian Lampert, Horst Zajonc, Elmar Kotter, Mathias Langer, Martin Fiebich, Sebastian M Goerke
PURPOSE: To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures. METHODS: As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care), RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging...
2016: PloS One
https://www.readbyqxmd.com/read/27782858/registration-uncertainties-between-3d-cone-beam-computed-tomography-and-different-reference-ct-datasets-in-lung-stereotactic-body-radiation-therapy
#15
Markus Oechsner, Barbara Chizzali, Michal Devecka, Stephanie Elisabeth Combs, Jan Jakob Wilkens, Marciana Nona Duma
BACKGROUND: The aim of this study was to analyze differences in couch shifts (setup errors) resulting from image registration of different CT datasets with free breathing cone beam CTs (FB-CBCT). As well automatic as manual image registrations were performed and registration results were correlated to tumor characteristics. METHODS: FB-CBCT image registration was performed for 49 patients with lung lesions using slow planning CT (PCT), average intensity projection (AIP), maximum intensity projection (MIP) and mid-ventilation CTs (MidV) as reference images...
October 26, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27782691/technical-note-scuda-a-software-platform-for-cumulative-dose-assessment
#16
Seyoun Park, Todd McNutt, William Plishker, Harry Quon, John Wong, Raj Shekhar, Junghoon Lee
PURPOSE: Accurate tracking of anatomical changes and computation of actually delivered dose to the patient are critical for successful adaptive radiation therapy (ART). Additionally, efficient data management and fast processing are practically important for the adoption in clinic as ART involves a large amount of image and treatment data. The purpose of this study was to develop an accurate and efficient Software platform for CUmulative Dose Assessment (scuda) that can be seamlessly integrated into the clinical workflow...
October 2016: Medical Physics
https://www.readbyqxmd.com/read/27765832/imaging-dose-of-human-organs-from-kv-cbct-in-image-guided-radiation-therapy
#17
Kihong Son, Jin Sung Kim, Hoyeon Lee, Seungryong Cho
This study investigates dose distribution due to kV cone-beam computed tomography (CBCT) for the patients undergoing CBCT-based image-guided radiation therapy (IGRT). The kV-CBCT provides an efficient image-guidance tool for acquiring the latest volumetric image of a patient's anatomy, and has been being routinely used in clinics for an accurate treatment setup. Imaging radiation doses resulting from six different acquisition protocols of the on-board imager (OBI) were calculated using a Geant4 Application for Tomographic Emission (GATE) Monte Carlo simulation toolkit, and the absorbed doses by various organs were analyzed for the adult and pediatric numerical XCAT phantoms in this study...
October 20, 2016: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/27747639/evaluation-of-the-maxillary-sinus-in-panoramic-radiography-a-comparative-study
#18
Johann Malina-Altzinger, Georg Damerau, Klaus W Grätz, P D Bernd Stadlinger
BACKGROUND: The aim of this study was to evaluate the validity and the inter- and intra-examiner reliability of panoramic-radiograph-driven findings of different maxillary sinus anatomic variations and pathologies, which had initially been prediagnosed by cone beam computed tomography (CBCT). METHODS: After pairs of two-dimensional (2D) panoramic and three-dimensional (3D) CBCT images of patients having received treatment at the outpatient department had been screened, the predefinition of 54 selected maxillary sinus conditions was initially performed on CBCT images by two blinded consultants individually using a questionnaire that defined ten different clinically relevant findings...
December 2015: International Journal of Implant Dentistry
https://www.readbyqxmd.com/read/27716681/separable-scatter-model-of-the-detector-and%C3%A2-object-contributions-using-continuously-thickness-adapted-kernels-in-cbct
#19
Navnina Bhatia, David Tisseur, Solene Valton, Jean Michel Létang
Due to the increased cone beam coverage and the introduction of flat panel detector, the size of X-ray illumination fields has grown dramatically in Cone Beam Computed Tomography (CBCT), causing an increase in scatter radiation. Existing reconstruction algorithms do not model the scatter radiation, so scatter artifacts appear in the reconstruction images. The contribution of scattering of photons inside the detector itself becomes prominent and challenging in case of X-ray source of high energy (over a few 100 keV) which is used in typical industrial Non Destructive Testing (NDT)...
October 6, 2016: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/27709803/inter-scan-and-inter-observer-tumour-volume-delineation-variability-on-cone-beam-computed-tomography-in-patients-treated-with-stereotactic-body-radiation-therapy-for-early-stage-non-small-cell-lung-cancer
#20
Ying Hou, Stephanie Lee, Vishesh Agrawal, John Romano, Elizabeth H Baldini, Aileen B Chen, David E Kozono, Joseph H Killoran, Matthew Wagar, Fred L Hacker, Hugo Jwl Aerts, John H Lewis, Raymond H Mak
INTRODUCTION: Quantification of volume changes on cone beam computed tomography (CBCT) during lung stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) may provide a useful radiological marker for radiation response and for adaptive treatment planning. This study quantifies inter-scan and inter-observer variability in tumour volume delineation on CBCT. METHODS: Three clinicians independently contoured the primary gross tumour volume (GTV) manually on CBCTs taken immediately before SBRT treatment (pre) and after the same SBRT treatment (post) for 19 NSCLC patients...
October 5, 2016: Journal of Medical Imaging and Radiation Oncology
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