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https://www.readbyqxmd.com/read/29166133/dosimetric-impact-of-gastrointestinal-air-column-in-radiation-treatment-of-pancreatic-cancer
#1
Neil C Estabrook, Jonathan B Corn, Marvene E Ewing, Higinia R Cardenes, Indra J Das
OBJECTIVE: Dosimetric evaluation of air column in gastro-intestinal (GI) structures in IMRT of pancreatic cancer. METHODS: Nine sequential patients were retrospectively chosen for dosimetric analysis of air column in the GI apparatus in pancreatic cancer using cone beam CT (CBCT). The 4DCT was used for target and organs at risk (OARs) and non-coplanar IMRT was used for treatment. Once/week, these patients underwent CBCT for air filling, isocenter verification and dose calculations retrospectively...
November 22, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/29154259/evaluation-of-coefficients-to-derive-organ-and-effective-doses-from-cone-beam-ct-cbct-scans-a-monte-carlo-study
#2
Abdullah Abuhaimed, Colin J Martin
Regular imaging is used throughout image guided radiation therapy (IGRT) to improve treatment delivery. In order for treatment procedures to be optimized, the doses delivered by imaging exposures should be taken into account. CT dosimetry methods based on the CT dose index (CTDI), measured with a 100 mm long pencil ionization chamber (CTDI<sub>100</sub>) in standard phantoms, are not designed for the cone beam CT (CBCT) imaging systems used in radiotherapy, therefore a modified version has been proposed for CBCT by the International Electrotechnical Commission (CTDI<sub>IEC</sub>)...
November 20, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/29153368/diagnostic-value-of-cone-beam-computed-tomography-cbct-in-occult-scaphoid-and-wrist-fractures
#3
Christophe Borel, Ahmed Larbi, Stephanie Delclaux, Franck Lapegue, Helene Chiavassa-Gandois, Nicolas Sans, Marie Faruch-Bilfeld
OBJECTIVE: Evaluate the diagnostic value of cone beam computed tomography (CBCT) for scaphoid and wrist fractures that are missed on standard radiographs. MATERIALS AND METHODS: Between September 2014 and October 2015, we prospectively enrolled 49 patients with a clinically suspected scaphoid fracture following an acute injury but had normal radiographs. Each patients underwent radiographs, CBCT and (magnetic resonance imaging) MRI within 7days of the initial injury event...
December 2017: European Journal of 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/29116054/non-rigid-ct-cbct-to-cbct-registration-for-online-external-beam-radiotherapy-guidance
#7
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/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
#8
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/29071800/national-survey-on-image-guided-radiotherapy-practice-in-new-zealand
#9
Jerusha Padayachee, Jasmin Loh, Albert Tiong, Louis Lao
INTRODUCTION: This survey aimed to assess the use of image-guided radiotherapy (IGRT) within New Zealand (NZ) and evaluate the quality of IGRT delivery. METHOD: All nine centres in NZ were invited to participate in an online survey in November 2015. Questions were asked on type of IGRT technologies available, IGRT use by tumour site and frequency of imaging. In addition, questions were asked in reference to the American Society for Radiation Oncology (ASTRO) White Paper recommendations on safe practice of IGRT...
October 26, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/29040707/effective-radiation-dose-in-the-wrist-resulting-from-a-radiographic-device-two-cbct-devices-and-one-msct-device-a-comparative-study
#10
Juha Koivisto, Maureen van Eijnatten, Timo Kiljunen, Xie-Qi Shi, Jan Wolff
The objective of the present study was to assess and compare the effective doses in the wrist region resulting from conventional radiography device, multislice computed tomography (MSCT) device and two cone beam computed tomography (CBCT) devices using MOSFET dosemeters and a custom made anthropomorphic RANDO phantom according to the ICRP 103 recommendation. The effective dose for the conventional radiography was 1.0 μSv. The effective doses for the NewTom 5 G CBCT ranged between 0.7 μSv and 1.6 μSv, for the Planmed Verity CBCT 2...
October 13, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29031916/image-guided-adaptive-external-beam-radiation-therapy-for-cervix-cancer-evaluation-of-a-clinically-implemented-plan-of-the-day-technique
#11
Martin Buschmann, Katarina Majercakova, Alina Sturdza, Stephanie Smet, Dina Najjari, Michaela Daniel, Richard Pötter, Dietmar Georg, Yvette Seppenwoolde
BACKGROUND: Radiotherapy for cervix cancer is challenging in patients exhibiting large daily changes in the pelvic anatomy, therefore adaptive treatments (ART) have been proposed. The aim of this study was the clinical implementation and subsequent evaluation of plan-of-the-day (POTD)-ART for cervix cancer in supine positioning. The described workflow was based on standard commercial equipment and current quality assurance (QA) methods. MATERIALS AND METHODS: A POTD strategy, which employs a VMAT plan library consisting of an empty bladder plan, a full bladder plan and a motion robust backup plan, was developed...
October 11, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28981411/z-index-parameterization-zip-for-volumetric-ct-image-reconstruction-via-3d-dictionary-learning
#12
Ti Bai, Hao Yan, Xun Jia, Steve Jiang, Ge Wang, Xuanqin Mou
Despite the rapid developments of x-ray cone-beam CT (CBCT), image noise still remains a major issue for the low dose CBCT. To suppress the noise effectively while retain the structures well for low dose CBCT image, in this work, a sparse constraint based on the 3D dictionary is incorporated into a regularized iterative reconstruction framework, defining the 3DDL method. In addition, by analyzing the sparsity level curve associated with different regularization parameters, a new adaptive parameter selection strategy is proposed to facilitate our 3DDL method...
October 5, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28980445/dosimetric-effects-of-anatomical-changes-during-fractionated-photon-radiation-therapy-in-pancreatic-cancer-patients
#13
Astrid van der Horst, Antonetta C Houweling, Geertjan van Tienhoven, Jorrit Visser, Arjan Bel
Pancreatic tumors show large interfractional position variation. In addition, changes in gastrointestinal gas volumes and body contour take place over the course of radiation therapy. We aimed to quantify the effect of these anatomical changes on target dose coverage, for the clinically used fiducial marker-based patient position verification and, for comparison, also for simulated bony anatomy-based position verification. Nine consecutive patients were included in this retrospective study. To enable fraction dose calculations on cone-beam CT (CBCT), the planning CT was deformably registered to each CBCT (13-15 per patient); gas volumes visible on CBCT were copied to the deformed CT...
October 4, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28967334/when-is-cone-beam-computed-tomography-imaging-appropriate-for-diagnostic-inquiry-in-the-management-of-inflammatory-periodontitis-an-american-academy-of-periodontology-best-evidence-review
#14
David M Kim, Seyed Hossein Bassir
BACKGROUND: Clinical and radiographic examinations are essential in establishing correct periodontal diagnoses as well as providing appropriate treatment options. Current radiographic examinations, however, do not provide adequate information regarding the severity of periodontal disease, presenting a need to investigate alternative methods. The aim of this best evidence consensus is to determine when cone-beam computed tomography (CBCT) imaging is appropriate for diagnostic inquiry in the management of inflammatory periodontitis...
October 2017: Journal of Periodontology
https://www.readbyqxmd.com/read/28967330/the-use-of-cone-beam-computed-tomography-in-management-of-patients-requiring-dental-implants-an-american-academy-of-periodontology-best-evidence-review
#15
Hector F Rios, Wenche S Borgnakke, Erika Benavides
BACKGROUND: Application of cone-beam computed tomography (CBCT) has grown exponentially across dentistry with a clear impact in implant dentistry. This review aims at providing the scientific context to understand if CBCT imaging should become the standard of care for patients requiring dental implants. METHODS: A literature search for CBCT applications in implant dentistry was performed using the PubMed database that included studies published between January 1, 2000, and June 24, 2017...
October 2017: Journal of Periodontology
https://www.readbyqxmd.com/read/28952463/a-monte-carlo-study-of-organ-and-effective-doses-of-cone-beam-computed-tomography-cbct-scans-in-radiotherapy
#16
Abdullah Abuhaimed, Colin J Martin, Marimuthu Sankaralingam
Cone-beam CT (CBCT) scans utilized for image guided radiation therapy (IGRT) procedures have become an essential part of radiotherapy. The aim of this study was to assess organ and effective doses resulting from new CBCT scan protocols (head, thorax, and pelvis) released with a software upgrade of the kV on-board-imager (OBI) system. Influence of the scan parameters that were changed in the new protocols on the patient dose was also investigated. Organ and effective doses for protocols of the new software (V2...
September 27, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28944361/cone-beam-computed-tomography-with-ultra-low-dose-protocols-for-pre-implant-radiographic-assessment-an-in-vitro-study
#17
Robert Liljeholm, Nils Kadesjö, Daniel Benchimol, Kristina Hellén-Halme, Xie-Qi Shi
PURPOSE: To evaluate the ultra-low dose scanning protocols of a newly developed CBCT for pre-implant radiographic assessment. MATERIALS AND METHODS: A total number of 32 CBCT scans were exposed at 90 kV using ProMax 3D's standard (GS) and three ultra-low dose scanning protocols: high, mid and low definition (UL-HD, UL-MD and UL-LD) on eight human dry skulls with simulated soft tissue. The mAs values and the voxel size were 96mAs/200 µm, 28mAs/150 µm, 22.4mAs/200 µm and 7...
2017: European Journal of Oral Implantology
https://www.readbyqxmd.com/read/28942233/comparison-of-radiation-doses-imparted-during-128-256-384-multislice-ct-scanners-and-cone-beam-computed-tomography-for-intra-and-perioperative-cochlear-implant-assessment
#18
N Guberina, U Dietrich, D Arweiler-Harbeck, M Forsting, A Ringelstein
PURPOSE: To examine radiation-doses imparted during multislice (MSCT) and cone-beam computed-tomography (CBCT) for perioperative examination of cochlear-implant insertion. METHODS: Radiation-doses were assessed during standardized petrous-bone CT-protocols at different MSCT ((I) single-source CT-scanner Somatom-Definition-AS+, (II) 2nd generation of dual-source CT-scanner Somatom-Definition-Flash, (III) 3rd generation of dual-source CT-scanner Somatom-Force and at the CBCT Ziehm-Vision-RFD3D ((IV) (a) RFD-3D (Standard-modifier), (b) RFD-3D (Low-dose-modifier))...
September 19, 2017: American Journal of Otolaryngology
https://www.readbyqxmd.com/read/28932947/integration-of-digital-dental-casts-in-cone-beam-computed-tomography-scans-a-clinical-validation-study
#19
Frits A Rangel, Thomas J J Maal, Martien J J de Koning, Ewald M Bronkhorst, Stefaan J Bergé, Anne Marie Kuijpers-Jagtman
OBJECTIVES: Images derived from cone beam computed tomography (CBCT) scans lack detailed information on the dentition and interocclusal relationships needed for proper surgical planning and production of surgical splints. To get a proper representation of the dentition, integration of a digital dental model into the CBCT scan is necessary. The aim of this study was to validate a simplified protocol to integrate digital dental models into CBCT scans using only one scan. MATERIALS AND METHODS: Conventional protocol A used one combined upper and lower impression and two CBCT scans...
September 20, 2017: Clinical Oral Investigations
https://www.readbyqxmd.com/read/28901659/using-gamma-index-to-flag-changes-in-anatomy-during-image-guided-radiation-therapy-of-head-and-neck-cancer
#20
Bryan Schaly, Jeff Kempe, Varagur Venkatesan, Sylvia Mitchell, Jerry J Battista
During radiation therapy of head and neck cancer, the decision to consider replanning a treatment because of anatomical changes has significant resource implications. We developed an algorithm that compares cone-beam computed tomography (CBCT) image pairs and provides an automatic alert as to when remedial action may be required. Retrospective CBCT data from ten head and neck cancer patients that were replanned during their treatment was used to train the algorithm on when to recommend a repeat CT simulation (re-CT)...
September 13, 2017: Journal of Applied Clinical Medical Physics
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