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CBCT Radiation

Nathan Cho, Panagiotis Tsiamas, Esteban Velarde, Erik Tryggestad, Robert Jacques, Ross Berbeco, Todd McNutt, Peter Kazanzides, John Wong
PURPOSE: The Small Animal Radiation Research Platform (SARRP) has been developed for conformal micro irradiation with on-board cone-beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS) for SARRP. This paper describes the validation of the SC method for the kilovoltage energy by comparing with EBT2 film measurements and Monte Carlo (MC) simulations...
March 15, 2018: Medical Physics
Yingxuan Chen, Fang-Fang Yin, Yawei Zhang, You Zhang, Lei Ren
Compressed sensing reconstruction using total variation (TV) tends to over-smooth the edge information by uniformly penalizing the image gradient. The goal of this study is to develop a novel prior contour based TV (PCTV) method to enhance the edge information in compressed sensing reconstruction for CBCT. 
 Methods: The edge information is extracted from prior planning-CT via edge detection. Prior CT is first registered with on-board CBCT reconstructed with TV method through rigid or deformable registration...
March 14, 2018: Physics in Medicine and Biology
Jan Brandt, Martin Brenner, Hans-Christoph Lauer, Silvia Brandt
PURPOSE: The aim of this in vitro study was to evaluate the accuracy of template-guided implantation planned with implant-planning software (Implant Studio), comparing computer-aided design/computer-assisted manufacture (CAD/CAM)-based measurements with measurements via cone beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty template-guided implantations were planned and performed on acrylic-resin models. The implant positions were detected with an intraoral scanner, evaluated with CAD quality-control software, and compared with the planned positions in the test group...
March 2018: International Journal of Oral & Maxillofacial Implants
Jie Wei, Ming Chao
PURPOSE: We presented a feasibility study to extract the diaphragm motion from the inferior contrast cone beam computed tomography (CBCT) projection images using a constrained linear regression optimization algorithm. METHODS: The shape of the diaphragm was fitted by a parabolic function which was initialized by five manually placed points on the diaphragm contour of a pre-selected projection. A constrained linear regression model by exploiting the spatial, algebraic, and temporal constraints of the diaphragm, approximated by a parabola, was employed to estimate the parameters...
February 2018: Physica Medica: PM
Mohammad Haekal, Hidetaka Arimura, Taka-Aki Hirose, Yusuke Shibayama, Saiji Ohga, Junichi Fukunaga, Yoshiyuki Umezu, Hiroshi Honda, Tomonari Sasaki
PURPOSE: To analyze the uncertainties of the rectum due to anisotropic shape variations by using a statistical point distribution model (PDM). MATERIALS AND METHODS: The PDM was applied to the rectum contours that were delineated on planning computed tomography (CT) and cone-beam CT (CBCT) at 80 fractions of 11 patients. The standard deviations (SDs) of systematic and random errors of the shape variations of the whole rectum and the region in which the rectum overlapped with the PTV (ROP regions) were derived from the PDMs at all fractions of each patient...
February 2018: Physica Medica: PM
Ching-Ching Yang, Pei-Chieh Yu, Jau-Ming Ruan, Yu-Cheng Chen
PURPOSE: The target detectability of cone beam computed tomography (CBCT) performed in image-guided radiation therapy (IGRT) was investigated to achieve sufficient image quality for patient positioning over a course of treatment session while maintaining radiation exposure from CBCT imaging as low as reasonably achievable (ALARA). METHODS: Body CBCT scans operated in half-fan mode were acquired with three different protocols: CBCTlowD , CBCTmidD , and CBCThighD , which resulted in weighted CT dose index (CTDIw ) of 0...
March 8, 2018: Journal of Applied Clinical Medical Physics
H Kamezawa, H Arimura, H Arakawa, N Kameda
The purpose of this study was to investigate a practical patient dose index for assessing the patient organ dose from a cone-beam computed tomography (CBCT) scan by comparing eight dose indices, i.e. CTDI100, CTDIIEC, CTDI∞, midpoint doses f(0)PMMA for a cylindrical polymethyl methacrylate (PMMA) phantom, f(0)Ap for an anthropomorphic phantom and f(0)Pat for a prostate cancer patient, as well as the conventional size specific dose estimations (SSDEconv) and modified SSDE (SSDEmod), with organ dose for the prostate (ODprost) obtained via Monte Carlo (MC) simulation...
March 1, 2018: Radiation Protection Dosimetry
Laura Wanner, Ute Ludwig, Jan-Bernd Hövener, Katja Nelson, Tabea Flügge
OBJECTIVE: Compared with cone beam computed tomography (CBCT), magnetic resonance imaging (MRI) might be superior for the diagnosis of nerve lesions associated with implant placement. STUDY DESIGN: A patient presented with unilateral pain associated with dysesthesia in the region of the right lower lip and chin after implant placement. Conventional orthopantomography could not identify an association between the position of the inferior alveolar nerve and the implant...
January 31, 2018: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Yuting Li, Tucker Netherton, Paige L Nitsch, Peter A Balter, Song Gao, Ann H Klopp, Laurence E Court
PURPOSE: The aim of this study was to measure and compare the mega-voltage imaging dose from the Halcyon medical linear accelerator (Varian Medical Systems) with measured imaging doses with the dose calculated by Eclipse treatment planning system. METHODS: An anthropomorphic thorax phantom was imaged using all imaging techniques available with the Halcyon linac - MV cone-beam computed tomography (MV-CBCT) and orthogonal anterior-posterior/lateral pairs (MV-MV), both with high-quality and low-dose modes...
March 3, 2018: Journal of Applied Clinical Medical Physics
N Befrui, M Fischer, B Fuerst, S-C Lee, J Fotouhi, S Weidert, A Johnson, E Euler, G Osgood, N Navab, W Böcker
BACKGROUND: Despite great advances in the development of hardware and software components, surgical navigation systems have only seen limited use in current clinical settings due to their reported complexity, difficulty of integration into clinical workflows and questionable advantages over traditional imaging modalities. OBJECTIVES: Development of augmented reality (AR) visualization for surgical navigation without the need for infrared (IR) tracking markers and comparison of the navigation system to conventional imaging...
March 2, 2018: Der Unfallchirurg
Jaroma Antti, Suomalainen Juha-Sampo, Niemitukia Lea, Soininvaara Tarja, Salo Jari, Kröger Heikki
Background Computed tomography (CT) can be used to assess the rotational alignment of prosthesis components to identify possible underlying causes of symptomatic total knee arthroplasty (TKA). The use of cone beam computed tomography (CBCT) for the imaging of extremities is relatively new, although it has been widely used in dental imaging. Purpose To assess the intra- and inter-observer reproducibility of CBCT, as well as to validate CBCT for TKA component and periprosthetic bone diagnostics. Material and Methods CBCT scans were performed on 18 patients the day before a scheduled revision TKA, from which the intra- and inter-observer reproducibility were assessed...
January 1, 2018: Acta Radiologica
Elia Kodjo Chardey, Rosamaria Fastuca, Matteo Beretta, Alberto Di Blasio, Nicolò Vercellini, Alberto Caprioglio, Piero Antonio Zecca, Aldo Macchi
Objective: The aim of the present study is to propose a 3-dimensional evaluation of lower intrusion obtained with lingual orthodontics considering not only the crowns but also dental roots. Methods: 9 adult patients underwent fixed lingual orthodontic treatment with i-TTя lingual brackets system for the correction of crowding in the lower arch associated with a deep overbite. Initial records, consisting of photos, CBCTs and intraoral scans were collected. Threshold segmentation of the CBCT was performed to generate a three-dimensional virtual model of each the teeth of the lower arch, superimposed with the crown of the same teeth obtained by intraoral scan models to generate a complete set of digital composite lower arch The same procedure was performed to monitor one key step of the i-TTЯ technique consisting in lower incisors intrusion (T2)...
2018: Open Dentistry Journal
Nabil El Sahili, Ibrahim Nasseh, Antoine Berberi, Sandra David-Tchouda, Sophie Thoret, Thomas Fortin
Objectives: Cone-Beam Computed Tomography (CBCT) produces vital information required for the accurate and prudent placement of dental implants. Lack of standardization between CBCT machines may result in unsafe patient exposure to harmful radiation; higher doses are not necessarily associated with improved image quality. Aim: The study aimed to assess the influence of low- and high-dose milliamperage settings on CBCT images for objective and subjective implant planning...
2018: Open Dentistry Journal
Gerlig Widmann, Asma'a A Al-Ekrish
Introduction: The Council Directive 2013/59 Euratom has a clear commitment for keeping medical radiation exposure as low as reasonably achievable and demands a regular review and use of diagnostic reference levels. Methods: In dental implantology, the range of effective doses for cone beam computed tomography (CBCT) shows a broad overlap with multislice computed tomography (MSCT). More recently, ultralow dose imaging with new generations of MSCT scanners may impart radiation doses equal to or lower than CBCT...
2018: Open Dentistry Journal
M Jonczyk, F Collettini, D Geisel, D Schnapauff, G Böning, G Wieners, G Gebauer
Background During transarterial chemoembolization (TACE), cone-beam computed tomography (CBCT) can be used for tumor and feeding vessel detection as well as postembolization CT imaging. However, there will be additional radiation exposure from CBCT. Purpose To evaluate the additional dose raised through CBCT-assisted guidance in comparison to TACE procedures guided with pulsed digital subtraction angiography (DSA) alone. Material and Methods In 70 of 140 consecutive patients undergoing TACE for liver cancer, CBCT was used to facilitate the TACE...
January 1, 2018: Acta Radiologica
C Noblet, G Delpon, S Supiot, V Potiron, F Paris, S Chiavassa
BACKGROUND: In pre-clinical animal experiments, radiation delivery is usually delivered with kV photon beams, in contrast to the MV beams used in clinical irradiation, because of the small size of the animals. At this medium energy range, however, the contribution of the photoelectric effect to absorbed dose is significant. Accurate dose calculation therefore requires a more detailed tissue definition because both density (ρ) and elemental composition (Zeff ) affect the dose distribution...
February 26, 2018: Radiation Oncology
Y Du, W Zhou, Y Pan, Y Tang, L Wan, H Jiang
BACKGROUND: Older alveolar cleft patients (>12 years old) often have wide bone defect as well as teeth loss, resulting in poor osseous healing with conventional alveolar bone grafting (ABG). In this study, we investigated a surgical technique of block iliac bone grafting for the alveolar cleft reconstruction and evaluated the clinical and radiological outcomes of these cleft patients. MATERIAL AND METHODS: Fifteen patients were included in this study. All cases received preoperative cone bean computed tomography (CBCT) scans for the alveolar cleft evaluation...
February 24, 2018: Medicina Oral, Patología Oral y Cirugía Bucal
Yoshinobu Shimohigashi, Fujio Araki, Masato Maruyama, Keisuke Yonemura, Yuji Nakaguchi, Yudai Kai, Ryo Toya
In this study, qualities of 4D cone-beam CT (CBCT) images obtained using various gantry rotation speeds (GRSs) for liver stereotactic body radiation therapy (SBRT) with fiducial markers were quantitatively evaluated. Abdominal phantom containing a fiducial marker was moved along a sinusoidal waveform, and 4D-CBCT images were acquired with GRSs of 50-200° min-1 . We obtained the 4D-CBCT projection data from six patients who underwent liver SBRT and generated 4D-CBCT images at GRSs of 67-200° min-1 , by varying the number of projection data points...
January 2018: Physica Medica: PM
Reshma Munbodh, Jonathan P S Knisely, David A Jaffray, Douglas J Moseley
PURPOSE: We present and evaluate a fully automated 2D-3D intensity-based registration framework using a single limited field-of-view (FOV) 2D kV radiograph and a 3D kV CBCT for 3D estimation of patient setup errors during brain radiotherapy. METHODS: We evaluated two similarity measures, the Pearson correlation coefficient on image intensity values (ICC) and maximum likelihood measure with Gaussian noise (MLG), derived from the statistics of transmission images...
February 22, 2018: Medical Physics
George X Ding, Parham Alaei, Bruce Curran, Ryan Flynn, Michael Gossman, T Rock Mackie, Moyed Miften, Richard Morin, X George Xu, Timothy C Zhu
With radiotherapy having entered the era of image guidance, or image-guided radiation therapy (IGRT), imaging procedures are routinely performed for patient positioning and target localization. The imaging dose delivered may result in excessive dose to sensitive organs and potentially increase the chance of secondary cancers and, therefore, needs to be managed. This task group was charged with: a) providing an overview on imaging dose, including megavoltage electronic portal imaging (MV EPI), kilovoltage digital radiography (kV DR), Tomotherapy MV-CT, megavoltage cone-beam CT (MV-CBCT) and kilovoltage cone-beam CT (kV-CBCT), and b) providing general guidelines for commissioning dose calculation methods and managing imaging dose to patients...
February 22, 2018: Medical Physics
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