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Sample records for cone beam sanjigen

  1. Cone beam CT, wat moet ik ermee?

    NARCIS (Netherlands)

    R. Hoogeveen

    2013-01-01

    De cone beam-ct-scan (cbct-scan) maakt een opmars in de tandheelkunde vanwege de toegevoegde waarde van de derde dimensie in de diagnostiek. Deze extra informatie wordt verkregen ten koste van een hogere stralenbelasting en een daarmee gepaard gaand hoger risico voor de patiënt. Om de clinicus te he

  2. Cone beam computed tomography in veterinary dentistry

    NARCIS (Netherlands)

    van Thielen, B.; Siguenza, F.; Hassan, B.

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal reconstruc

  3. Cone beam computed tomography in veterinary dentistry

    NARCIS (Netherlands)

    van Thielen, B.; Siguenza, F.; Hassan, B.

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal reconstruc

  4. Cone Beam Computed Tomography - Know its Secrets

    OpenAIRE

    Kumar, Mohan; Shanavas, Muhammad; Sidappa, Ashwin; Kiran, Madhu

    2015-01-01

    Cone-beam computed tomography (CBCT) is an advanced imaging modality that has high clinical applications in the field of dentistry. CBCT proved to be a successful investigative modality that has been used for dental and maxillofacial imaging. Radiation exposure dose from CBCT is 10 times less than from conventional CT scans during maxillofacial exposure. Furthermore, CBCT is highly accurate and can provide a three-dimensional volumetric data in axial, sagittal and coronal planes. This article...

  5. Cone beam computed tomography use in orthodontics.

    Science.gov (United States)

    Nervina, J M

    2012-03-01

    Cone beam computed tomography (CBCT) is widely used by orthodontists to obtain three-dimensional (3-D) images of their patients. This is of value as malocclusion results from discrepancies in three planes of space. This review tracks the use of CBCT in orthodontics, from its validation as an accurate and reliable tool, to its use in diagnosing and treatment planning, and in assessing treatment outcomes in orthodontics.

  6. Cone beam computed tomography in endodontic

    Energy Technology Data Exchange (ETDEWEB)

    Durack, Conor; Patel, Shanon, E-mail: conordurack1@hotmail.com [Unit of Endodontology, Department of Conservative Dentistry, King' s College London, London (United Kingdom)

    2012-07-01

    Cone beam computed tomography (CBCT) is a contemporary, radiological imaging system designed specifically for use on the maxillofacial skeleton. The system overcomes many of the limitations of conventional radiography by producing undistorted, three-dimensional images of the area under examination. These properties make this form of imaging particularly suitable for use in endodontic. The clinician can obtain an enhanced appreciation of the anatomy being assessed, leading to an improvement in the detection of endodontic disease and resulting in more effective treatment planning. In addition, CBCT operates with a significantly lower effective radiation dose when compared with conventional computed tomography (CT). The purpose of this paper is to review the current literature relating to the limitations and potential applications of CBCT in endodontic practice. (author)

  7. Cone beam computed tomography in endodontics.

    Science.gov (United States)

    Durack, Conor; Patel, Shanon

    2012-01-01

    Cone beam computed tomography (CBCT) is a contemporary, radiological imaging system designed specifically for use on the maxillo-facial skeleton. The system overcomes many of the limitations of conventional radiography by producing undistorted, three-dimensional images of the area under examination. These properties make this form of imaging particularly suitable for use in endodontics. The clinician can obtain an enhanced appreciation of the anatomy being assessed, leading to an improvement in the detection of endodontic disease and resulting in more effective treatment planning. In addition, CBCT operates with a significantly lower effective radiation dose when compared with conventional computed tomography (CT). The purpose of this paper is to review the current literature relating to the limitations and potential applications of CBCT in endodontic practice.

  8. Pulsar average waveforms and hollow cone beam models

    Science.gov (United States)

    Backer, D. C.

    1975-01-01

    An analysis of pulsar average waveforms at radio frequencies from 40 MHz to 15 GHz is presented. The analysis is based on the hypothesis that the observer sees one cut of a hollow-cone beam pattern and that stationary properties of the emission vary over the cone. The distributions of apparent cone widths for different observed forms of the average pulse profiles (single, double/unresolved, double/resolved, triple and multiple) are in modest agreement with a model of a circular hollow-cone beam with random observer-spin axis orientation, a random cone axis-spin axis alignment, and a small range of physical hollow-cone parameters for all objects.

  9. Bessel-like beams with z-dependent cone angles

    CSIR Research Space (South Africa)

    Belyi, VN

    2009-08-01

    Full Text Available A new type of Bessel-like optical beams, which is distinguished by the dependence on the cone angle from the longitudinal coordinate, is investigated. Such beams have the properties of Bessel beams (ring-spatial spatial spectrum) as well as Gaussian...

  10. Generalized Fourier slice theorem for cone-beam image reconstruction.

    Science.gov (United States)

    Zhao, Shuang-Ren; Jiang, Dazong; Yang, Kevin; Yang, Kang

    2015-01-01

    The cone-beam reconstruction theory has been proposed by Kirillov in 1961, Tuy in 1983, Feldkamp in 1984, Smith in 1985, Pierre Grangeat in 1990. The Fourier slice theorem is proposed by Bracewell 1956, which leads to the Fourier image reconstruction method for parallel-beam geometry. The Fourier slice theorem is extended to fan-beam geometry by Zhao in 1993 and 1995. By combining the above mentioned cone-beam image reconstruction theory and the above mentioned Fourier slice theory of fan-beam geometry, the Fourier slice theorem in cone-beam geometry is proposed by Zhao 1995 in short conference publication. This article offers the details of the derivation and implementation of this Fourier slice theorem for cone-beam geometry. Especially the problem of the reconstruction from Fourier domain has been overcome, which is that the value of in the origin of Fourier space is 0/0. The 0/0 type of limit is proper handled. As examples, the implementation results for the single circle and two perpendicular circle source orbits are shown. In the cone-beam reconstruction if a interpolation process is considered, the number of the calculations for the generalized Fourier slice theorem algorithm is O(N^4), which is close to the filtered back-projection method, here N is the image size of 1-dimension. However the interpolation process can be avoid, in that case the number of the calculations is O(N5).

  11. Pulsar average wave forms and hollow-cone beam models

    Science.gov (United States)

    Backer, D. C.

    1976-01-01

    Pulsar wave forms have been analyzed from observations conducted over a wide radio-frequency range to assess the wave-form morphologies and to measure wave-form widths. The results of the analysis compare favorably with the predictions of a model with a hollow-cone beam of fixed dimensions and with random orientation of both the observer and the cone axis with respect to the pulsar spin axis. A class of three-component wave forms is included in the model by adding a central pencil beam to the hollow-cone hypothesis. The consequences of a number of discrepancies between observations and quantitative predictions of the model are discussed.

  12. Comparative analysis between mandibular positions in centric relation and maximum intercuspation by cone beam computed tomography (CONE-BEAM)

    OpenAIRE

    Ferreira,Amanda de Freitas; Henriques,João César Guimarães; Almeida,Guilherme de Araújo; Machado,Asbel Rodrigues; Machado, Naila Aparecida de Godoi; Fernandes Neto,Alfredo Júlio

    2009-01-01

    This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandi...

  13. X-ray cone beam CT system calibration

    Science.gov (United States)

    Sire, Pascal; Rizo, Philippe; Martin, M.

    1993-12-01

    Recently x-ray cone beam computed tomography (CT) has become of interest for nondestructive testing (NDT) of advanced materials. Such a technique takes advantage of the cone beam geometry, to reduce the acquisition time and increase the resolution. Performances of CT systems rely mainly on geometric precision and measurement quality. Inaccurate geometry or incorrect data produce artifacts and blurring which limit the spatial resolution. A precise geometric calibration procedure is required and some corrections must be applied to the raw attenuation data in order to obtain accurate measurements. An x-ray cone beam CT system has been developed at the LETI. This machine was designed to control small parts limited to a few centimeters, with a high spatial resolution close to 30 microns. This paper introduces the machine setup and describes the calibration computing resources involved in the system. Then, we discuss the performances on experimental data.

  14. A Statistical Approach to Motion Compensated Cone Beam Reconstruction

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Hansen, Mads Fogtmann; Larsen, Rasmus

    2010-01-01

    One of the problems arising in radiotherapy planning is the quality of CT planning data. In the following attention is giving to the cone-beam scanning geometry where reconstruction of a 3D volume based on 2D projections, using the classic Feldkamp-Davis-Kress (FDK) algorithm requires a large...

  15. Cone-beam CT-guidance in Interventional Radiology

    NARCIS (Netherlands)

    Braak, S.J.

    2012-01-01

    OBJECTIVE. CBCT-guidance (CBCT-guidance) is a new stereotactic technique for needle interventions, combining 3D soft-tissue cone-beam CT, needle planningsoftware, and real-time fluoroscopy. Our objective was to evaluate the use, feasibility and outcome of this technique. To determine the effectiv

  16. Increasing Cone-beam projection usage by temporal fitting

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Hansen, Mads Fogtmann; Larsen, Rasmus

    2010-01-01

    A Cone-beam CT system can be used to image the lung region. The system records 2D projections which will allow 3D reconstruction however a reconstruction based on all projections will lead to a blurred reconstruction in regions were respiratory motion occur. To avoid this the projections are typi...

  17. A statistical approach to motion compensated cone-beam

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Hansen, Mads Fogtmann; Larsen, Rasmus

    One of the problems arising in radiotherapy planning is the quality of CT planning data. In the following attention is giving to the cone-beam scanning geometry where reconstruction of a 3D volume based on 2D projections, using the classic Feldkamp-Davis-Kress (FDK) algorithm requires a large...

  18. Cone beam computed tomography in Endodontics - a review

    NARCIS (Netherlands)

    Patel, S.; Durack, C.; Abella, F.; Shemesh, H.; Roig, M.; Lemberg, K.

    2015-01-01

    Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on

  19. A Clinical Evaluation Of Cone Beam Computed Tomography

    Science.gov (United States)

    2016-06-01

    subject number. The principal investigator collated all data collection sheets and organized them into a spreadsheet for final analysis. Data...available cone-beam computed tomography machine . Am J 01ihod Dentofacial Orthop 2008; 134:573-82. 7. Moshfeghi M, Tavakoli MA, Hosseini ET, et al

  20. Operator radiation exposure in cone-beam computed tomography guidance

    NARCIS (Netherlands)

    Braak, S.J.; Strijen Van, M. J L; Meijer, E.; Heesewijk Van, J. P M; Mali, W. P T M

    2016-01-01

    Objectives: Quantitative analysis of operator dose in cone-beam computed tomography guidance (CBCT-guidance) and the effect of protective shielding. Methods: Using a Rando phantom, a model was set-up to measure radiation dose for the operator hand, thyroid and gonad region. The effect of sterile rad

  1. Cone beam computed tomography in Endodontics - a review

    NARCIS (Netherlands)

    Patel, S.; Durack, C.; Abella, F.; Shemesh, H.; Roig, M.; Lemberg, K.

    2015-01-01

    Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on t

  2. Tomografía computarizada Cone Beam en endodoncia.

    OpenAIRE

    Oviedo Muñoz, Pámela; Facultad de Estomatología. Universidad Peruana Cayetano Heredia. Lima,; Hernández Añaños, Juan Felipe; Facultad de Estomatología, Universidad Peruana Cayetano Heredia. Lima,

    2014-01-01

    La tomografía computarizada Cone Beam gracias a los avances tecnológicos esta especialmente diseñada para producir imágenes de alta resolución e información tridimensional para aplicaciones dentales, esta tiene ventajas en la detección de los signos clínicos y la precisión en el diagnóstico. Además reduce el tiempo de exploración y sobre todo reduce la dosis de radiación en comparación de la tomografía computarizada tradicional.La tomografía computarizada Cone Beam y su aplicación en la endod...

  3. Cone beam CT in radiology; DVT in der Radiologie

    Energy Technology Data Exchange (ETDEWEB)

    Dammann, Florian [ALB FILS KLINIKEN GmbH, Klinik am Eichert, Goeppingen (Germany). Inst. fuer Radiologie

    2013-06-15

    Cone beam computed tomography (CBCT) is a cross-sectional X-ray modality using an imaging system with cone-beam geometry. Unlike CT, the data set is acquired in a single circulation of a C-arm shaped tube-detector unit. Image characteristics vs. exposure dose ratio is similar to conventional CT, but varies widely depending on the CBVT device and the selected settings, and is limited to low dose/high noise applications. Up to now, only few data is available to estimate the clinical value of CBCT. Nevertheless, the use of CBCT is increasing drastically in the recent years, especially in the dental and ENT diagnostic field. For this reason the European Commission recently published guidelines concerning the clinical application of CBCT. These guidelines, as well as clinically relevant technical features of CBCT and examples of the most frequent dental applications are presented in the following article. (orig.)

  4. Tomografía computarizada Cone Beam en endodoncia.

    OpenAIRE

    Oviedo Muñoz, Pámela; Facultad de Estomatología. Universidad Peruana Cayetano Heredia. Lima,; Hernández Añaños, Juan Felipe; Facultad de Estomatología, Universidad Peruana Cayetano Heredia. Lima,

    2014-01-01

    La tomografía computarizada Cone Beam gracias a los avances tecnológicos esta especialmente diseñada para producir imágenes de alta resolución e información tridimensional para aplicaciones dentales, esta tiene ventajas en la detección de los signos clínicos y la precisión en el diagnóstico. Además reduce el tiempo de exploración y sobre todo reduce la dosis de radiación en comparación de la tomografía computarizada tradicional.La tomografía computarizada Cone Beam y su aplicación en la endod...

  5. Mandibular condyle position in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Hyoung Joo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Kyung Hee Univ. School of Dentistry, Seoul (Korea, Republic of)

    2006-06-15

    To evaluate position of the mandibular condyle within articular fossa in an asymptomatic population radiographically by a cone beam computed tomography. Cone beam computed tomography of 60 temporomandibular joints was performed on 15 males and 15 females with no history of any temporomandibular disorders, or any other orthodontic or photoconductors treatments. Position of mandibular condyle within articular fossa at centric occlusion was evaluated. A statistical evaluation was done using a SPSS. In the sagittal views, mandibular condyle within articular fossa was laterally located at central section. Mandibular condyles in the right and left sides were showed asymmetric positional relationship at medial, central, and lateral sections. Mandibular condyle within articular fossa in an asymptomatic population was observed non-concentric position in the sagittal and coronal views.

  6. Cone beam CT for dental and maxillofacial imaging: dose matters

    OpenAIRE

    Pauwels, Ruben

    2015-01-01

    The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiogr...

  7. Use of Cone Beam Computed Tomography in Endodontics

    Science.gov (United States)

    Scarfe, William C.; Levin, Martin D.; Gane, David; Farman, Allan G.

    2009-01-01

    Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imaging adjunct for endodontics. PMID:20379362

  8. Cone beam computed tomography in Endodontics - a review.

    Science.gov (United States)

    Patel, S; Durack, C; Abella, F; Shemesh, H; Roig, M; Lemberg, K

    2015-01-01

    Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on the applications and limitations of CBCT; (ii) make recommendations for the use of CBCT in Endodontics; (iii) highlight areas of further research of CBCT in Endodontics. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  9. Cone beam CT in orthodontics: the current picture.

    Science.gov (United States)

    Makdissi, Jimmy

    2013-03-01

    The introduction of cone beam computed tomography (CBCT) technology to dentistry and orthodontics revolutionized the diagnosis, treatment and monitoring of orthodontic patients. This review article discusses the use of CBCT in diagnosis and treatment planning in orthodontics. The steps required to install and operate a CBCT facility within the orthodontic practice as well as the challenges are highlighted. The available guidelines in relation to the clinical applications of CBCT in orthodontics are explored. Copyright © 2013. Published by Elsevier Masson SAS.

  10. A Clinical Evaluation of Cone Beam Computed Tomography

    Science.gov (United States)

    2013-07-31

    multidetector computed tomography and cone beam computed tomography in the assessment of dental implant site dimensions. Dentomaxillofac Radiol 2011;40:67-75...submitted to the Faculty of the Endodontics Graduate Program Naval Postgraduate Dental School Uniformed Services University of the Health Sciences...in partial fulfillment of the requirements of the degree of Master of Science in Oral Biology June 2013 Naval Postgraduate Dental

  11. Use of Cone Beam Computed Tomography in Endodontics

    OpenAIRE

    Scarfe, William C.; Martin D. Levin; David Gane; Farman, Allan G.

    2009-01-01

    Cone Beam Computed Tomography (CBCT) is a diagnostic imaging modality that provides high-quality, accurate three-dimensional (3D) representations of the osseous elements of the maxillofacial skeleton. CBCT systems are available that provide small field of view images at low dose with sufficient spatial resolution for applications in endodontic diagnosis, treatment guidance, and posttreatment evaluation. This article provides a literature review and pictorial demonstration of CBCT as an imagin...

  12. Development of an advanced 3D cone beam tomographic system

    Science.gov (United States)

    Sire, Pascal; Rizo, Philippe; Martin, M.; Grangeat, Pierre; Morisseau, P.

    Due to its high spatial resolution, the 3D X-ray cone-beam tomograph (CT) maximizes understanding of test object microstructure. In order for the present X-ray CT NDT system to control ceramics and ceramic-matrix composites, its spatial resolution must exceed 50 microns. Attention is given to two experimental data reconstructions that have been conducted to illustrate system capabilities.

  13. A Clinical Evaluation of Cone Beam Computed Tomography

    Science.gov (United States)

    2015-06-01

    include areas of differing, non- homogenous, densities. Because the information is digital, the reconstruction algorithm will calculate a weighted average...homogenous voxels may present as a stair step boundmy in the image (Ballrick, Palomo, Ruch, Amberman, & Hans, 2008). 2. "Under sampling" occurs...al suggests 5 specific findings on a cone beam CT that may assist in the detection of vertical root fracture: 1. Loss of bone in the mid-root area

  14. Anatomical structure of lingual foramen in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ki, Min Woo; Hwang, Eui Hwan; Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    2004-07-15

    To evaluate whether cone beam computed tomography can depict the distribution, position, frequency, relative vertical dimension, and the diameter of the lingual foramen and direction of lingual bone canal. Cone beam computed tomography of mandible was performed on 25 males and 25 females with no history of any orthodontic treatments or any other dental surgeries. A statistical comparison was done on the mean values of males and females. In the location and distribution of lingual foramina, median lingual foramen was found in all subjects and lateral lingual foramen in 58%. In the lateral lingual foramen, bilateral type was found in 28% and unilateral type in 30%. In the number of lingual foramina, median lingual foramen had two foramina and lateral lingual foramen had one foramen, mostly. In the relative mean vertical dimension of lingual foramina, median lingual foramen was 0.03 {+-} 0.08, and both lateral lingual foramina was 0.20 {+-} 0.04. The mean diameter of lingual foramina, median lingual foramen was 0.9 mm {+-} 0.28, right lateral lingual foramen was 0.92 mm {+-} 0.23, and left lateral lingual foramen was 0.88 mm {+-} 0.27. The most frequent direction of the lingual bone canals, median lingual bone canal proceeded in anteroinferior direction and lateral lingual bone canal in anterosuperolateral direction. Cone beam computed tomography can be helpful for surgery and implantation on the mandibular area. Radiologist should be aware of this anatomical feature and its possible implications.

  15. Commissioning kilovoltage cone-beam CT beams in a radiation therapy treatment planning system.

    Science.gov (United States)

    Alaei, Parham; Spezi, Emiliano

    2012-11-08

    The feasibility of accounting of the dose from kilovoltage cone-beam CT in treatment planning has been discussed previously for a single cone-beam CT (CBCT) beam from one manufacturer. Modeling the beams and computing the dose from the full set of beams produced by a kilovoltage cone-beam CT system requires extensive beam data collection and verification, and is the purpose of this work. The beams generated by Elekta X-ray volume imaging (XVI) kilovoltage CBCT (kV CBCT) system for various cassettes and filters have been modeled in the Philips Pinnacle treatment planning system (TPS) and used to compute dose to stack and anthropomorphic phantoms. The results were then compared to measurements made using thermoluminescent dosimeters (TLDs) and Monte Carlo (MC) simulations. The agreement between modeled and measured depth-dose and cross profiles is within 2% at depths beyond 1 cm for depth-dose curves, and for regions within the beam (excluding penumbra) for cross profiles. The agreements between TPS-calculated doses, TLD measurements, and Monte Carlo simulations are generally within 5% in the stack phantom and 10% in the anthropomorphic phantom, with larger variations observed for some of the measurement/calculation points. Dose computation using modeled beams is reasonably accurate, except for regions that include bony anatomy. Inclusion of this dose in treatment plans can lead to more accurate dose prediction, especially when the doses to organs at risk are of importance.

  16. Intra–cavity generation of Bessel–like beams with longitudinally dependent cone angles

    CSIR Research Space (South Africa)

    Litvin, IA

    2010-02-01

    Full Text Available The authors report on two resonator systems for producing Bessel–like beams with longitudinally dependent cone angles (LDBLBs). Such beams have extended propagation distances as compared to conventional Bessel– Gauss beams, with a far field pattern...

  17. Comparative analysis between mandibular positions in centric relation and maximum intercuspation by cone beam computed tomography (CONE-BEAM).

    Science.gov (United States)

    Ferreira, Amanda de Freitas; Henriques, João César Guimarães; Almeida, Guilherme Araújo; Machado, Asbel Rodrigues; Machado, Naila Aparecida de Godoi; Fernandes Neto, Alfredo Júlio

    2009-01-01

    This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00), and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left). By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.

  18. Comparative analysis between mandibular positions in centric relation and maximum intercuspation by cone beam computed tomography (CONE-BEAM

    Directory of Open Access Journals (Sweden)

    Amanda de Freitas Ferreira

    2009-01-01

    Full Text Available This research consisted of a quantitative assessment, and aimed to measure the possible discrepancies between the maxillomandibular positions for centric relation (CR and maximum intercuspation (MI, using computed tomography volumetric cone beam (cone beam method. The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion: normal occlusion and Angle Class I occlusion. In order to obtain the centric relation, a JIG device and mandible manipulation were used to deprogram the habitual conditions of the jaw. The evaluations were conducted in both frontal and lateral tomographic images, showing the condyle/articular fossa relation. The images were processed in the software included in the NewTom 3G device (QR NNT software version 2.00, and 8 tomographic images were obtained per patient, four laterally and four frontally exhibiting the TMA's (in CR and MI, on both sides, right and left. By means of tools included in another software, linear and angular measurements were performed and statistically analyzed by student t test. According to the methodology and the analysis performed in asymptomatic patients, it was not possible to detect statistically significant differences between the positions of centric relation and maximum intercuspation. However, the resources of cone beam tomography are of extreme relevance to the completion of further studies that use heterogeneous groups of samples in order to compare the results.

  19. Superior performance of cone beam tomography in detecting a calcaneus fracture.

    Science.gov (United States)

    Lohse, Christian; Catala-Lehnen, Philip; Regier, Marc; Heiland, Max

    2015-01-01

    Cone beam computed tomography is a state-of-the-art imaging tool, initially developed for dental and maxillofacial application. With its high resolution and low radiation dose, cone beam tomography has been expanding its application fields, for example, to diagnosis of traumata and fractures in the head and neck area. In this study, we demonstrate superior and satisfactory performance of cone beam tomography for the imaging of a calcaneus fracture in comparison to conventional X-ray and computed tomography.

  20. Rapidly converging multigrid reconstruction of cone-beam tomographic data

    Science.gov (United States)

    Myers, Glenn R.; Kingston, Andrew M.; Latham, Shane J.; Recur, Benoit; Li, Thomas; Turner, Michael L.; Beeching, Levi; Sheppard, Adrian P.

    2016-10-01

    In the context of large-angle cone-beam tomography (CBCT), we present a practical iterative reconstruction (IR) scheme designed for rapid convergence as required for large datasets. The robustness of the reconstruction is provided by the "space-filling" source trajectory along which the experimental data is collected. The speed of convergence is achieved by leveraging the highly isotropic nature of this trajectory to design an approximate deconvolution filter that serves as a pre-conditioner in a multi-grid scheme. We demonstrate this IR scheme for CBCT and compare convergence to that of more traditional techniques.

  1. Diagnostic Applications of Cone-Beam CT for Periodontal Diseases

    OpenAIRE

    AlJehani, Yousef A.

    2014-01-01

    Objectives. This paper aims to review the diagnostic application of cone beam computed tomography (CBCT) in the field of periodontology. Data. Original articles that reported on the use of CBCT for periodontal disease diagnosis were included. Sources. MEDLINE (1990 to January 2014), PubMed (using medical subject headings), and Google Scholar were searched using the following terms in different combinations: “CBCT,” “volumetric CT,” “periodontal disease ,” and “periodontitis.” This was supplem...

  2. Incidental findings on cone beam computed tomography: Relate and relay

    Directory of Open Access Journals (Sweden)

    Suhas P Pande

    2015-01-01

    Full Text Available Objective: To evaluate the presence of incidental findings on cone beam computed tomography (CBCT images and to recognize their clinical importance. Materials and Methods: A total of 700 CBCT scans between January 2013 to August 2014 at Government Dental College and Hospital were evaluated retrospectively. Results: 459 incidental findings (65.57% were observed in 700 patients. Most common individual incidental finding was mucosal thickening (119 followed by pineal/habenula calcification (99 and choroid plexus (77. Conclusion: The oral and maxillofacial radiologist should carefully interpret all scans and should not ignore the incidental findings and hence avoid untoward snowballing effects.

  3. Cone-beam computed tomography: A miracle for orthodontics!

    Directory of Open Access Journals (Sweden)

    Jeevan M Khatri

    2015-01-01

    Full Text Available The branch of oral medicine and radiology has always played a role of back stage worker for the branch of orthodontics and dentofacial orthopaedics. It would have been difficult for an orthodontist to gift the bright smiles to his/her patients without the 2D and 3D black and white pictures provided by the oral radiologist. Moreover, the series of advances in the various imaging modalities are playing the role of a magician for the branch of orthodontia. The present article provides valuable information about one such miracle for the field of orthodontics-cone beam computed tomography (CBCT.

  4. Auto calibration of a cone-beam-CT

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Daniel; Heil, Ulrich; Schulze, Ralf; Schoemer, Elmar; Schwanecke, Ulrich [Department of Design, Computer Science and Media, RheinMain University of Applied Sciences, 65195 Wiesbaden, Germany and Institute of Computer Science, Johannes Gutenberg University Mainz, 55128 Mainz (Germany); Department of Oral Surgery (and Oral Radiology), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz (Germany); Institute of Computer Science, Johannes Gutenberg University Mainz, 55128 Mainz (Germany); Department of Design, Computer Science and Media, RheinMain University of Applied Sciences, 65195 Wiesbaden (Germany)

    2012-10-15

    Purpose: This paper introduces a novel autocalibration method for cone-beam-CTs (CBCT) or flat-panel CTs, assuming a perfect rotation. The method is based on ellipse-fitting. Autocalibration refers to accurate recovery of the geometric alignment of a CBCT device from projection images alone, without any manual measurements. Methods: The authors use test objects containing small arbitrarily positioned radio-opaque markers. No information regarding the relative positions of the markers is used. In practice, the authors use three to eight metal ball bearings (diameter of 1 mm), e.g., positioned roughly in a vertical line such that their projection image curves on the detector preferably form large ellipses over the circular orbit. From this ellipse-to-curve mapping and also from its inversion the authors derive an explicit formula. Nonlinear optimization based on this mapping enables them to determine the six relevant parameters of the system up to the device rotation angle, which is sufficient to define the geometry of a CBCT-machine assuming a perfect rotational movement. These parameters also include out-of-plane rotations. The authors evaluate their method by simulation based on data used in two similar approaches [L. Smekal, M. Kachelriess, S. E, and K. Wa, 'Geometric misalignment and calibration in cone-beam tomography,' Med. Phys. 31(12), 3242-3266 (2004); K. Yang, A. L. C. Kwan, D. F. Miller, and J. M. Boone, 'A geometric calibration method for cone beam CT systems,' Med. Phys. 33(6), 1695-1706 (2006)]. This allows a direct comparison of accuracy. Furthermore, the authors present real-world 3D reconstructions of a dry human spine segment and an electronic device. The reconstructions were computed from projections taken with a commercial dental CBCT device having two different focus-to-detector distances that were both calibrated with their method. The authors compare their reconstruction with a reconstruction computed by the manufacturer of

  5. Calibration of Cone Beam Rotational X-Ray Image Sequence

    Institute of Scientific and Technical Information of China (English)

    YUHengyong; MOUXuanqin; CAIYuanlong

    2004-01-01

    The real X-ray projection does not abide by Lambert-Beer Law, since the X-ray is polychromatic and the imaging chains are nonlinear. Based on the generating process of X-ray images, an equivalent nonlinear transform model is firstly proposed which considers all the nonlinear factors as one nonlinear transform. Then the 3D (three-dimensional) X-ray projection of cone beam is defined. The constraints of Radon transform, named H-L (Helgasson-ludwig) consistency conditions, are expanded to fan-beam. After that an algorithm is developed to calibrate Rotational X-ray image sequence (RXIS). The algorithm uses a set of exponential functions to approximate the nonlinear inverse transform. According to expanded H-L consistency conditions, finally a kind of nonlinear measure for RXIS is defined. Experimental results show that the proposed algorithm can decrease the nonlinear measure to below 0.01.

  6. Reduction of beam hardening artifacts in cone-beam CT imaging via SMART-RECON algorithm

    Science.gov (United States)

    Li, Yinsheng; Garrett, John; Chen, Guang-Hong

    2016-03-01

    When an automatic exposure control is introduced in C-arm cone beam CT data acquisition, the spectral inconsistencies between acquired projection data are exacerbated. As a result, conventional water/bone correction schemes are not as effective as in conventional diagnostic x-ray CT acquisitions with a fixed tube potential. In this paper, a new method was proposed to reconstruct several images with different degrees of spectral consistency and thus different levels of beam hardening artifacts. The new method relies neither on prior knowledge of the x-ray beam spectrum nor on prior compositional information of the imaging object. Numerical simulations were used to validate the algorithm.

  7. Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model

    OpenAIRE

    Cai, Weixing; zhao,binghui; Conover, David; Liu, Jiangkun; Ning, Ruola

    2012-01-01

    Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan.

  8. Experience of direct percutaneous sac injection in type II endoleak using cone beam computed tomography.

    Science.gov (United States)

    Park, Yoong-Seok; Do, Young Soo; Park, Hong Suk; Park, Kwang Bo; Kim, Dong-Ik

    2015-04-01

    Cone beam CT, usually used in dental area, could easily obtain 3-dimensional images using cone beam shaped ionized radiation. Cone beam CT is very useful for direct percutaneous sac injection (DPSI) which needs very precise measurement to avoid puncture of inferior vena cava or vessel around sac or stent graft. Here we describe two cases of DPSI using cone beam CT. In case 1, a 79-year-old male had widening of preexisted type II endoleak after endovascular aneurysm repair (EVAR). However, transarterial embolization failed due to tortuous collateral branches of lumbar arteries. In case 2, a 72-year-old female had symptomatic sac enlargement by type II endoleak after EVAR. However, there was no route to approach the lumbar arteries. Therefore, we performed DPSI assisted by cone beam CT in cases 1, 2. Six-month CT follow-up revealed no sign of sac enlargement by type II endoleak.

  9. Cone beam computed tomography: A boon for maxillofacial imaging

    Directory of Open Access Journals (Sweden)

    Sreenivas Rao Ghali

    2017-01-01

    Full Text Available In day to day practice, the radiographic techniques used individually or in combination suffer from some inherent limits of all planar two-dimensional (2D projections such as magnification, distortion, superimposition, and misrepresentation of anatomic structures. The introduction of cone-beam computed tomography (CBCT, specifically dedicated to imaging the maxillofacial region, heralds a major shift from 2D to three-dimensional (3D approach. It provides a complete 3D view of the maxilla, mandible, teeth, and supporting structures with relatively high resolution allowing a more accurate diagnosis, treatment planning and monitoring, and analysis of outcomes than conventional 2D images, along with low radiation exposure to the patient. CBCT has opened up new vistas for the use of 3D imaging as a diagnostic and treatment planning tool in dentistry. This paper provides an overview of the imaging principles, underlying technology, dental applications, and in particular focuses on the emerging role of CBCT in dentistry.

  10. Diagnostic Applications of Cone-Beam CT for Periodontal Diseases

    Directory of Open Access Journals (Sweden)

    Yousef A. AlJehani

    2014-01-01

    Full Text Available Objectives. This paper aims to review the diagnostic application of cone beam computed tomography (CBCT in the field of periodontology. Data. Original articles that reported on the use of CBCT for periodontal disease diagnosis were included. Sources. MEDLINE (1990 to January 2014, PubMed (using medical subject headings, and Google Scholar were searched using the following terms in different combinations: “CBCT,” “volumetric CT,” “periodontal disease ,” and “periodontitis.” This was supplemented by hand-searching in peer-reviewed journals and cross-referenced with the articles accessed. Conclusions. Bony defects, caters, and furcation involvements seem to be better depicted on CBCT, whereas bone quality and periodontal ligament space scored better on conventional intraoral radiography. CBCT does not offer a significant advantage over conventional radiography for assessing the periodontal bone levels.

  11. Computer aided breast density evaluation in cone beam breast CT

    Science.gov (United States)

    Zhang, Xiaohua; Ning, Ruola

    2011-03-01

    Cone Beam Breast CT is a three-dimensional breast imaging modality with high contrast resolution and no tissue overlap. With these advantages, it is possible to measure volumetric breast density accurately and quantitatively with CBBCT 3D images. Three major breast components need to be segmented: skin, fat and glandular tissue. In this research, a modified morphological processing is applied to the CBBCT images to detect and remove the skin of the breast. After the skin is removed, a 2-step fuzzy clustering scheme is applied to the CBBCT image volume to adaptively cluster the image voxels into fat and glandular tissue areas based on the intensity of each voxel. Finally, the CBBCT breast volume images are divided into three categories: skin, fat and glands. Clinical data is used and the quantitative CBBCT breast density evaluation results are compared with the mammogram-based BIRADS breast density categories.

  12. Dose calculation based on Cone Beam CT images

    DEFF Research Database (Denmark)

    Slot Thing, Rune

    , several other factors contributing to the image quality degradation, and while one should, theoretically, be able to obtain CT-like image quality from CBCT scans, clinical image quality is often very far from this ideal realisation. The present thesis describes the investigation of potential image quality...... improvements in clinical CBCT imaging achieved through post-processing of the clinical image data. A Monte Carlo model was established to predict patient specific scattered radiation in CBCT imaging, based on anatomical information from the planning CT scan. This allowed the time consuming Monte Carlo......Cone beam CT (CBCT) imaging is frequently used in modern radiotherapy to ensure the proper positioning of the patient prior to each treatment fraction. With the increasing use of CBCT imaging for image guidance, interest has grown in exploring the potential use of these 3– or 4–D medical images...

  13. Fossa navicularis magna detection on cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Ali Z. [Dept. of Oral and Maxillofacial Medicine and Diagnostic Sciences, School of Dental Medicine, Case Western Reserve University, Cleveland(United States); Mupparapu, Mel [Div. of Radiology, University of Pennsylvania School of Dental Medicine, Philadelphia (United States)

    2016-03-15

    Herein, we report and discuss the detection of fossa navicularis magna, a close radiographic anatomic variant of canalis basilaris medianus of the basiocciput, as an incidental finding in cone-beam computed tomography (CBCT) imaging. The CBCT data of the patients in question were referred for the evaluation of implant sites and to rule out pathology in the maxilla and mandible. CBCT analysis showed osseous, notch-like defects on the inferior aspect of the clivus in all four cases. The appearance of fossa navicularis magna varied among the cases. In some, it was completely within the basiocciput and mimicked a small rounded, corticated, lytic defect, whereas it appeared as a notch in others. Fossa navicularis magna is an anatomical variant that occurs on the inferior aspect of the clivus. The pertinent literature on the anatomical variations occurring in this region was reviewed.

  14. Comparing cone beam laminographic system trajectories for composite NDT

    Directory of Open Access Journals (Sweden)

    Neil O'Brien

    2016-11-01

    Full Text Available We compare the quality of reconstruction obtainable using various laminographic system trajectories that have been described in the literature, with reference to detecting defects in composite materials in engineering. We start by describing a laminar phantom representing a simplified model of composite panel, which models certain defects that may arise in such materials, such as voids, resin rich areas, and delamination, and additionally features both blind and through holes along multiple axes. We simulate ideal cone-beam projections of this phantom with the different laminographic trajectories, applying both Simultaneous Iterative Reconstruction Technique (SIRT and Conjugate Gradient Least Squares (CGLS reconstruction algorithms. We compare the quality of the reconstructions with a view towards optimising the scan parameters for defect detectability in composite NDT applications.

  15. Extracting respiratory signals from thoracic cone beam CT projections

    CERN Document Server

    Yan, Hao; Yin, Wotao; Pan, Tinsu; Ahmad, Moiz; Mou, Xuanqin; Cervino, Laura; Jia, Xun; Jiang, Steve B

    2012-01-01

    Patient respiratory signal associated with the cone beam CT (CBCT) projections is important for lung cancer radiotherapy. In contrast to monitoring an external surrogate of respiration, such signal can be extracted directly from the CBCT projections. In this paper, we propose a novel local principle component analysis (LPCA) method to extract the respiratory signal by distinguishing the respiration motion-induced content change from the gantry rotation-induced content change in the CBCT projections. The LPCA method is evaluated by comparing with three state-of-the-art projection-based methods, namely, the Amsterdam Shroud (AS) method, the intensity analysis (IA) method, and the Fourier-transform based phase analysis (FT-p) method. The clinical CBCT projection data of eight patients, acquired under various clinical scenarios, were used to investigate the performance of each method. We found that the proposed LPCA method has demonstrated the best overall performance for cases tested and thus is a promising tech...

  16. Application of cone beam computed tomography in facial imaging science

    Institute of Scientific and Technical Information of China (English)

    Zacharias Fourie; Janalt Damstra; Yijin Ren

    2012-01-01

    The use of three-dimensional (3D) methods for facial imaging has increased significantly over the past years.Traditional 2D imaging has gradually being replaced by 3D images in different disciplines,particularly in the fields of orthodontics,maxillofacial surgery,plastic and reconstructive surgery,neurosurgery and forensic sciences.In most cases,3D facial imaging overcomes the limitations of traditional 2D methods and provides the clinician with more accurate information regarding the soft-tissues and the underlying skeleton.The aim of this study was to review the types of imaging methods used for facial imaging.It is important to realize the difference between the types of 3D imaging methods as application and indications thereof may differ.Since 3D cone beam computed tomography (CBCT) imaging will play an increasingly importanl role in orthodontics and orthognathic surgery,special emphasis should be placed on discussing CBCT applications in facial evaluations.

  17. Cone beam computed tomography: A new vision in dentistry

    Directory of Open Access Journals (Sweden)

    Manas Gupta

    2015-01-01

    Full Text Available Cone beam computed tomography (CBCT is a developing imaging technique designed to provide relatively low-dose high-spatial-resolution visualization of high-contrast structures in the head and neck and other anatomic areas. It is a vital content of a dental patient's record. A literature review demonstrated that CBCT has been utilized for oral diagnosis, oral and maxillofacial surgery, endodontics, implantology, orthodontics; temporomandibular joint dysfunction, periodontics, and restorative and forensic dentistry. Recently, higher emphasis has been placed on the CBCT expertise, the three-dimensional (3D images, and virtual models. This literature review showed that the different indications for CBCT are governed by the needs of the specific dental discipline and the type of procedure performed.

  18. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    Science.gov (United States)

    Al-Sehaibany, Fares S; Marzouk, Hazem M; Salama, Fouad S

    2016-01-01

    A mesiodens is the most common type of supernumerary teeth. The purpose of this report is to present a rare occurrence of non-syndromic impacted inverted mesiodentes in an 8.5-year-old boy who presented with a chief complaint of delayed eruption of his permanent maxillary left central incisor. Occlusal and panoramic radiographs, as well as cone beam computed tomography (CBCT) with a three-dimensional (3-D) reconstruction image, confirmed that one supernumerary tooth had perforated the nasal fossa floor and the other was in close approximation to the to the same site. Surgical removal of both mesiodentes was indicated. Radiographic evidence of complete healing was observed 12 months following surgical removal. The use of CBCT with a 3-D reconstruction image as a tool in diagnosis and evaluation of healing after surgical removal is recommended.

  19. Iodine contrast cone beam CT imaging of breast cancer

    Science.gov (United States)

    Partain, Larry; Prionas, Stavros; Seppi, Edward; Virshup, Gary; Roos, Gerhard; Sutherland, Robert; Boone, John

    2007-03-01

    An iodine contrast agent, in conjunction with an X-ray cone beam CT imaging system, was used to clearly image three, biopsy verified, cancer lesions in two patients. The lesions were approximately in the 10 mm to 6 mm diameter range. Additional regions were also enhanced with approximate dimensions down to 1 mm or less in diameter. A flat panel detector, with 194 μm pixels in 2 x 2 binning mode, was used to obtain 500 projection images at 30 fps with an 80 kVp X-ray system operating at 112 mAs, for an 8-9 mGy dose - equivalent to two view mammography for these women. The patients were positioned prone, while the gantry rotated in the horizontal plane around the uncompressed, pendant breasts. This gantry rotated 360 degrees during the patient's 16.6 sec breath hold. A volume of 100 cc of 320 mg/ml iodine-contrast was power injected at 4 cc/sec, via catheter into the arm vein of the patient. The resulting 512 x 512 x 300 cone beam CT data set of Feldkamp reconstructed ~(0.3 mm) 3 voxels were analyzed. An interval of voxel contrast values, characteristic of the regions with iodine contrast enhancement, were used with surface rendering to clearly identify up to a total of 13 highlighted volumes. This included the three largest lesions, that were previously biopsied and confirmed to be malignant. The other ten highlighted regions, of smaller diameters, are likely areas of increased contrast trapping unrelated to cancer angiogenesis. However the technique itself is capable of resolving lesions that small.

  20. A new cone beam computerized tomography system for use in endodontic surgery.

    Science.gov (United States)

    Tsurumachi, T; Honda, K

    2007-03-01

    To present a newly developed cone beam computerized tomography system (3DX Micro-CT) and its application in endodontic surgery. Cone beam CT has attracted considerable attention as a new diagnostic imaging technique in dentistry. The assessment of fractured endodontic instruments and the planning of endodontic surgery present challenges that conventional radiography cannot meet successfully. In this report, the value of the 3DX cone beam computerized radiography system is illustrated by the case of a fractured endodontic instrument protruding into the maxillary sinus.

  1. Clinical utility of dental cone-beam computed tomography: current perspectives

    Directory of Open Access Journals (Sweden)

    Jaju PP

    2014-04-01

    Full Text Available Prashant P Jaju,1 Sushma P Jaju21Oral Medicine and Radiology, 2Conservative Dentistry and Endodontics, Rishiraj College of Dental Sciences and Research Center, Bhopal, IndiaAbstract: Panoramic radiography and computed tomography were the pillars of maxillofacial diagnosis. With the advent of cone-beam computed tomography, dental practice has seen a paradigm shift. This review article highlights the potential applications of cone-beam computed tomography in the fields of dental implantology and forensic dentistry, and its limitations in maxillofacial diagnosis.Keywords: dental implants, cone-beam computed tomography, panoramic radiography, computed tomography

  2. Is there a role for the use of volumetric cone beam computed tomography in periodontics?

    Science.gov (United States)

    du Bois, A H; Kardachi, B; Bartold, P M

    2012-03-01

    Volumetric computed cone beam tomography offers a number of significant advantages over conventional intraoral and extraoral panoramic radiography, as well as computed tomography. To date, periodontal diagnosis has relied heavily on the assessment of both intraoral radiographs and extraoral panoramic radiographs. With emerging technology in radiology there has been considerable interest in the role that volumetric cone beam computed tomography might play in periodontal diagnostics. This narrative reviews the current evidence and considers whether there is a role for volumetric cone beam computed tomography in periodontics.

  3. [Role of cone-beam computed tomography in diagnostic otorhinolaryngological imaging].

    Science.gov (United States)

    Perényi, Ádám; Bella, Zsolt; Baráth, Zoltán; Magyar, Péter; Nagy, Katalin; Rovó, László

    2016-01-10

    Accurate diagnosis and preoperative planning in modern otorhinolaryngology is strongly supported by imaging with enhanced visualization. Computed tomography is often used to examine structures within bone frameworks. Given the hazards of ionizing radiation, repetitive imaging studies exponentially increase the risk of damages to radiosensitive tissues. The authors compare multislice and cone-beam computed tomography and determine the role, advantages and disadvantages of cone-beam computed tomography in otorhinolaryngological imaging. They summarize the knowledge from the international literature and their individual imaging studies. They conclude that cone-beam computed tomography enables high-resolution imaging and reconstruction in any optional plane and in space with considerably lower effective radiation dose. Cone-beam computed tomography with appropriate indications proved to be an excellent diagnostic tool in otorhinolaryngological imaging. It makes an alternative to multislice computed tomography and it is an effective tool in perioperative and postoperative follow-up, especially in those cases which necessitate repetitive imaging with computed tomography.

  4. Assessment of buccal bone thickness of aesthetic maxillary region: a cone-beam computed tomography study

    National Research Council Canada - National Science Library

    Fuentes, Ramón; Flores, Tania; Navarro, Pablo; Salamanca, Carlos; Beltrán, Víctor; Borie, Eduardo

    2015-01-01

    The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT...

  5. 3D Cone Beam Volumetric Tomography Dedicated to Maxillofacial Radiology

    Directory of Open Access Journals (Sweden)

    Masoud Varshosaz

    2009-01-01

    Full Text Available   "nThe 3D cone beam volume/computed tomography (CBVT/CBCT has been designed for imaging the hard tissues of the maxillofacial region, although it has been used in some era of medical imaging for many years. CBVT is capable of providing a sub-millimeter resolution with the short scanning time of mostly less than 20 seconds and radiation dosages reportedly up to 15 times lower than those of spiral CT scans. In less than a decade, CBVT has revolutionized oral and maxillofacial radiology and is known as the “Standard of Care”. Although development was initially directed towards multiplanar viewing for dental implant and orthodontic treatment planning, secondary applications in other areas continue to expand such as maxillo-facial trauma, temporomandibular joint disorders, sinuse pathosis and upper airway evaluation. The intent of this presentation is to provide an overview of CBVT technology, advantages and disadvantages compared to the other modalities such as 2D images and medical CT and examples of justified cases in the oral & maxillofacial region.   

  6. Effective dose from cone beam CT examinations in dentistry.

    Science.gov (United States)

    Roberts, J A; Drage, N A; Davies, J; Thomas, D W

    2009-01-01

    Cone beam CT (CBCT) is becoming an increasingly utilized imaging modality for dental examinations in the UK. Previous studies have presented little information on patient dose for the range of fields of view (FOVs) that can be utilized. The purpose of the study was therefore to calculate the effective dose delivered to the patient during a selection of CBCT examinations performed in dentistry. In particular, the i-CAT CBCT scanner was investigated for several imaging protocols commonly used in clinical practice. A Rando phantom containing thermoluminescent dosemeters was scanned. Using both the 1990 and recently approved 2007 International Commission on Radiological Protection recommended tissue weighting factors, effective doses were calculated. The doses (E(1990), E(2007)) were: full FOV head (92.8 microSv, 206.2 microSv); 13 cm scan of the jaws (39.5 microSv, 133.9 microSv); 6 cm high-resolution mandible (47.2 microSv, 188.5 microSv); 6 cm high-resolution maxilla (18.5 microSv, 93.3 microSv); 6 cm standard mandible (23.9 microSv, 96.2 microSv); and 6 cm standard maxilla (9.7 microSv, 58.9 microSv). The doses from CBCT are low compared with conventional CT but significantly higher than conventional dental radiography techniques.

  7. Effective dose span of ten different cone beam CT devices.

    Science.gov (United States)

    Rottke, D; Patzelt, S; Poxleitner, P; Schulze, D

    2013-01-01

    Evaluation and reduction of dose are important issues. Since cone beam CT (CBCT) has been established now not just in dentistry, the number of acquired examinations continues to rise. Unfortunately, it is very difficult to compare the doses of available devices on the market owing to different exposition parameters, volumes and geometries. The aim of this study was to evaluate the spans of effective doses (EDs) of ten different CBCT devices. 48 thermoluminescent dosemeters were placed in 24 sites in a RANDO(®) head phantom. Protocols with lowest exposition parameters and protocols with highest exposition parameters were performed for each of the ten devices. The ED was calculated from the measured energy doses according to the International Commission on Radiological Protection 2007 recommendations for each protocol and device, and the statistical values were evaluated afterwards. The calculation of the ED resulted in values between 17.2 µSv and 396 µSv for the ten devices. The mean values for protocols with lowest and highest exposition parameters were 31.6 µSv and 209 µSv, respectively. It was not the aim of this study to evaluate the image quality depending on different exposition parameters but to define the spans of EDs in which different CBCT devices work. There is a wide span of ED for different CBCT devices depending on the selected exposition parameters, required spatial resolution and many other factors.

  8. Bone changes of mandibular condyle using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Un; Kim, Hyung Seop; Song, Ju Seop; Kim, Kyoung A; Koh, Kwang Joon [Chonbuk National Univ., Chonju (Korea, Republic of)

    2007-09-15

    To assess bone changes of mandibular condyle using cone beam computed tomography (CBCT) in temporomandibualr disorder (TMD) patients. 314 temporomandibular joints (TMJs) images of 163 TMD patients were examined at the Department of Oral and Maxillofacial Radiology, Chonbuk National University. The images were obtained by PSR9000N (Asahi Roentgen Co., Japan) and reconstructed by using Asahivision software (Asahi Roentgen Co., Japan). The CBCT images were examined three times with four weeks interval by three radiologists. Bone changes of mandibular condyle such as flattening, sclerosis, erosion and osteophyte formation were observed in sagittal, axial, coronal and 3 dimensional images of the mandibular condyle. The statistical analysis was performed using SPSS 12.0. Intra-and interobserver agreement were performed by 3 radiologists without the knowledge of clinical information. Osteopathy (2.9%) was found more frequently on anterior surface of the mandibular condyle. Erosion (31.8%) was found more frequently on anterior surface of the mandibular condyle. The intraobserver agreement was good to excellent (k=0.78{sub 0}.84), but interobserver agreement was fair (k=0.45). CBCT can provide high qualified images of bone changes of the TMJ with axial, coronal and 3 dimensional images.

  9. Use of cone beam computed tomography in periodontology.

    Science.gov (United States)

    Acar, Buket; Kamburoğlu, Kıvanç

    2014-05-28

    Diagnosis of periodontal disease mainly depends on clinical signs and symptoms. However, in the case of bone destruction, radiographs are valuable diagnostic tools as an adjunct to the clinical examination. Two dimensional periapical and panoramic radiographs are routinely used for diagnosing periodontal bone levels. In two dimensional imaging, evaluation of bone craters, lamina dura and periodontal bone level is limited by projection geometry and superpositions of adjacent anatomical structures. Those limitations of 2D radiographs can be eliminated by three-dimensional imaging techniques such as computed tomography. Cone beam computed tomography (CBCT) generates 3D volumetric images and is also commonly used in dentistry. All CBCT units provide axial, coronal and sagittal multi-planar reconstructed images without magnification. Also, panoramic images without distortion and magnification can be generated with curved planar reformation. CBCT displays 3D images that are necessary for the diagnosis of intra bony defects, furcation involvements and buccal/lingual bone destructions. CBCT applications provide obvious benefits in periodontics, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.

  10. Surgical stent for dental implant using cone beam CT images

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hyung Soo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kung Hee University, Seoul (Korea, Republic of)

    2010-12-15

    The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

  11. Cone beam computed tomography findings of impacted upper canines

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva Santos, Ludmilla Mota [Dept. of Endodontics, Aracatuba Dental School, Paulista State University, Aracatuba(Brazil); Bastos, Luana Costa; Da Silva, Silvio Jose Albergaria; Campos, Paulo Sergio Flores [School of Dentistry, Federal University of Bahia, Salvador (Brazil); Oliveira Santos, Christiano [Dept. of Stomatology, Oral Public Health, and Forensic Dentistry, School of Dentistry, University of Sao Paulo, Ribeirao Preto (Brazil); Neves, Frederico Sampaio [Dept. of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba (Brazil)

    2014-12-15

    To describe the features of impacted upper canines and their relationship with adjacent structures through three-dimensional cone-beam computed tomography (CBCT) images. Using the CBCT scans of 79 upper impacted canines, we evaluated the following parameters: gender, unilateral/bilateral occurrence, location, presence and degree of root resorption of adjacent teeth (mild, moderate, or severe), root dilaceration, dental follicle width, and presence of other associated local conditions. Most of the impacted canines were observed in females (56 cases), unilaterally (51 cases), and at a palatine location (53 cases). Root resorption in adjacent teeth and root dilaceration were observed in 55 and 47 impacted canines, respectively. In most of the cases, the width of the dental follicle of the canine was normal; it was abnormally wide in 20 cases. A statistically significant association was observed for all variables, except for root dilaceration (p=0.115) and the side of impaction (p=0.260). Root resorption of adjacent teeth was present in most cases of canine impaction, mostly affecting adjacent lateral incisors to a mild degree. A wide dental follicle of impacted canines was not associated with a higher incidence of external root resorption of adjacent teeth.

  12. Cone beam CT for dental and maxillofacial imaging: dose matters.

    Science.gov (United States)

    Pauwels, Ruben

    2015-07-01

    The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiographs, a routine or excessive use of CBCT would lead to a substantial increase of the collective patient dose. The potential use of CBCT for paediatric patients (e.g. developmental disorders, trauma and orthodontic treatment planning) further increases concern regarding its proper application. This paper provides an overview of justification and optimisation issues in dental and maxillofacial CBCT. The radiation dose in CBCT will be briefly reviewed. The European Commission's Evidence Based Guidelines prepared by the SEDENTEXCT Project Consortium will be summarised, and (in)appropriate use of CBCT will be illustrated for various dental applications.

  13. Classification of bifid mandibular canals using cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Gisele Maria Correr

    2013-12-01

    Full Text Available The objective of this study was to classify the morphology of bifid mandibular canals and to evaluate their relationship with the roots of third molars, using cone beam computed tomography (CBCT scans. The CBCT scans of 75 patients were analyzed and the bifurcations were classified according to Langlais et al. (1985. The relationship of bifurcation and third molars was established according to the following classification: class A - uninvolved, class B - close relationship, class C - intimate relationship and class D - absence of third molars. Data were submitted to descriptive statistics, and the results indicated that the patients' mean age was 48.2 (± 13.2 years. Unilateral bifurcation (Type 1 was the most frequent type (72.6%, followed by unilateral Type 2 (19.3%. Class D was the most frequent (57.33%, followed by class C (21.33%, class B (13.33% and class A (8%. It could be concluded that most cases presented unilateral bifid mandibular canals extending to the third molar or adjacent regions, and when present, the roots seemed to be a continuation of the bifid mandibular canal

  14. Cone-beam CT in diagnosis of scaphoid fractures

    Energy Technology Data Exchange (ETDEWEB)

    Edlund, Rolf; Lapidus, Gunilla; Baecklund, Jenny [Capio St Goeran' s Hospital, Department of Radiology, Stockholm (Sweden); Skorpil, Mikael [Karolinska University Hospital, Department of Radiology, Stockholm (Sweden); Karolinska Institutet, Department of Molecular Medicine and Surgery, Stockholm (Sweden)

    2016-02-15

    This prospective study investigated the sensitivity of cone beam computed tomography (CBCT), a low dose technique recently made available for extremity examinations, in detecting scaphoid fractures. Magnetic resonance imaging (MRI) was used as gold standard for scaphoid fractures. A total of 95 patients with a clinically suspected scaphoid fracture were examined with radiography and CBCT in the acute setting. A negative CBCT exam was followed by an MRI within 2 weeks. When a scaphoid fracture was detected on MRI a new CBCT was performed. Radiography depicted seven scaphoid fractures, all of which were also seen with CBCT. CBCT detected another four scaphoid fractures. With MRI another five scaphoid fractures were identified that were not seen with radiography or with CBCT. These were also not visible on the reexamination CBCT. Sensitivity for radiography was 44, 95 % confidence interval 21-69 %, and for CBCT 69 %, 95 % confidence interval 41-88 % (p = 0.12). Several non-scaphoid fractures in the carpal region were identified, radiography and CBCT depicted 7 and 34, respectively (p < 0.0001). CBCT is a superior alternative to radiography, entailing more accurate diagnoses of carpal region fractures, and thereby requiring fewer follow-up MRI examinations. However, CBCT cannot be used to exclude scaphoid fractures, since MRI identified additional occult scaphoid fractures. (orig.)

  15. Use of dentomaxillofacial cone beam computed tomography in dentistry

    Institute of Scientific and Technical Information of China (English)

    K?van?; Kamburo?lu

    2015-01-01

    Cone-beam computed tomography(CBCT) was developed and introduced specifically for dento-maxillofacial imaging. CBCT possesses a number of advantages over medical CT in clinical practice, such as lower effective radiation doses, lower costs, fewer space requirements,easier image acquisition, and interactive display modes such as mutiplanar reconstruction that are applicable to maxillofacial imaging. However, the disadvantages of CBCT include higher doses than two-dimensional imaging; the inability to accurately represent the internal structure of soft tissues and soft-tissue lesions; a limited correlation with Hounsfield Units for standardized quantification of bone density; and the presence of various types of image artifacts, mainly those produced by metal restorations. CBCT is now commonly used for a variety of purposes in oral implantology, dentomaxillofacial surgery, image-guided surgical procedures, endodontics, periodontics and orthodontics. CBCT applications provide obvious benefits in the assessment of dentomaxillofacial region, however; it should be used only in correct indications considering the necessity and the potential hazards of the examination.

  16. Practical applications of cone-beam computed tomography in orthodontics.

    Science.gov (United States)

    Mah, James K; Huang, John C; Choo, HyeRan

    2010-10-01

    Comprehensive visualization and records of the craniofacial complex have been goals in orthodontic imaging. These tasks have been performed by means of plaster, photographs and radiographs. These approaches have evolved across time, and cone-beam computed tomography (CBCT) has emerged as a comprehensive imaging modality for orthodontics. The authors provide a practical guide for applying CBCT in orthodontics, with an emphasis on situations in which conventional imaging is limited. These situations include dental development, limits of tooth movement, airway assessment, craniofacial morphology and superimposition. Complexities of the craniofacial complex, dentition and airway present challenges in obtaining conventional images. CBCT has image-fidelity advantages over conventional imaging that can lead to improved visualization. CBCT is changing orthodontics with respect to clinically assessing patients and is evolving with respect to diagnosis, clinical techniques and outcomes. The clinical value proposition of CBCT is to describe craniofacial anatomy accurately and provide comprehensive information regarding anatomical relationships and individual patient findings for improved diagnosis, treatment planning and prognostication.

  17. Descriptive study of apical periodontitis detected in Cone Beam Computed Tomography scans

    OpenAIRE

    MORETI,Lucieni Cristina Trovati; PANZARELLA,Francine Kühl; OLIVEIRA,Marine de; José Luiz Cintra JUNQUEIRA; MANHÃES JÚNIOR,Luiz Roberto

    2016-01-01

    ABSTRACT Objective: To perform a descriptive study in order to evaluate apical periodontitis in endodontically treated teeth using cone beam computed tomography. Methods: Eighty-six exams presenting at least one apical periodontitis were selected and divided into two groups: 1 for the mandible and 2 for the maxilla. All the exams were done using the same cone beam computed tomography with standard acquisition settings. All the images were processed and manipulated using the same software. T...

  18. Radiation protection: protection of patients undergoing cone beam computed tomography examinations.

    Science.gov (United States)

    Drage, Nicholas; Carmichael, Fiona; Brown, Jackie

    2010-10-01

    Cone beam computed tomography is becoming a popular imaging modality in dentistry. The effective dose from these examinations is generally higher than conventional plain film radiography. This article outlines the ways of protecting patients from the harmful effects of radiation. Cone beam computed tomography is an emerging imaging modality. The effective doses are generally higher than conventional radiography and it is therefore important that anyone requesting or performing these investigations understands how to keep the doses to patients as low as reasonably practicable.

  19. Full data consistency conditions for cone-beam projections with sources on a plane.

    Science.gov (United States)

    Clackdoyle, Rolf; Desbat, Laurent

    2013-12-07

    Cone-beam consistency conditions (also known as range conditions) are mathematical relationships between different cone-beam projections, and they therefore describe the redundancy or overlap of information between projections. These redundancies have often been exploited for applications in image reconstruction. In this work we describe new consistency conditions for cone-beam projections whose source positions lie on a plane. A further restriction is that the target object must not intersect this plane. The conditions require that moments of the cone-beam projections be polynomial functions of the source positions, with some additional constraints on the coefficients of the polynomials. A precise description of the consistency conditions is that the four parameters of the cone-beam projections (two for the detector, two for the source position) can be expressed with just three variables, using a certain formulation involving homogeneous polynomials. The main contribution of this work is our demonstration that these conditions are not only necessary, but also sufficient. Thus the consistency conditions completely characterize all redundancies, so no other independent conditions are possible and in this sense the conditions are full. The idea of the proof is to use the known consistency conditions for 3D parallel projections, and to then apply a 1996 theorem of Edholm and Danielsson that links parallel to cone-beam projections. The consistency conditions are illustrated with a simulation example.

  20. Dental cone beam computed tomography: justification for use in planning oral implant placement.

    Science.gov (United States)

    Jacobs, Reinhilde; Quirynen, Marc

    2014-10-01

    Intra-oral and panoramic radiographs are most frequently used in oral health care. Yet, the inherent nature of jaws and teeth renders three-dimensional diagnosis essential, especially in relation to oral surgery. Nowadays, this can be accomplished by dental cone beam computed tomography, which provides high-quality images at low radiation doses and low costs. Nonetheless, the effective dose ranges of cone beam computed tomography machines may easily vary from 10 to 1000 μSv, this being equivalent to two to 200 panoramic radiographs, even for similar presurgical indications. Moreover, the diagnostic image quality varies massively among available machines and parameter settings. Apart from the radiodiagnostic possibilities, dental cone beam computed tomography may offer a vast therapeutic potential, including opportunities for surgical guidance and further prosthetic rehabilitation via computer-aided design/computer-aided manufacturing solutions. These additional options may definitely explain part of the success of cone beam computed tomography for oral implant placement. In conclusion, dental cone beam computed tomography imaging could be justified for oral implant-related diagnosis, planning and transfer to surgical and further prosthetic treatment, but guidelines for justification and cone beam computed tomography optimization remain mandatory.

  1. Dynamic bowtie filter for cone-beam/multi-slice CT.

    Directory of Open Access Journals (Sweden)

    Fenglin Liu

    Full Text Available A pre-patient attenuator ("bowtie filter" or "bowtie" is used to modulate an incoming x-ray beam as a function of the angle of the x-ray with respect to a patient to balance the photon flux on a detector array. While the current dynamic bowtie design is focused on fan-beam geometry, in this study we propose a methodology for dynamic bowtie design in multi-slice/cone-beam geometry. The proposed 3D dynamic bowtie is an extension of the 2D prior art. The 3D bowtie consists of a highly attenuating bowtie (HB filled in with heavy liquid and a weakly attenuating bowtie (WB immersed in the liquid of the HB. The HB targets a balanced flux distribution on a detector array when no object is in the field of view (FOV. The WB compensates for an object in the FOV, and hence is a scaled-down version of the object. The WB is rotated and translated in synchrony with the source rotation and patient translation so that the overall flux balance is maintained on the detector array. First, the mathematical models of different scanning modes are established for an elliptical water phantom. Then, a numerical simulation study is performed to compare the performance of the scanning modes in the cases of the water phantom and a patient cross-section without any bowtie and with a dynamic bowtie. The dynamic bowtie can equalize the numbers of detected photons in the case of the water phantom. In practical cases, the dynamic bowtie can effectively reduce the dynamic range of detected signals inside the FOV. Furthermore, the WB can be individualized using a 3D printing technique as the gold standard. We have extended the dynamic bowtie concept from 2D to 3D by using highly attenuating liquid and moving a scale-reduced negative copy of an object being scanned. Our methodology can be applied to reduce radiation dose and facilitate photon-counting detection.

  2. Filtered region of interest cone-beam rotational angiography

    Energy Technology Data Exchange (ETDEWEB)

    Schafer, Sebastian; Noeel, Peter B.; Walczak, Alan M.; Hoffmann, Kenneth R. [Department of Mechanical Engineering, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Computer Science, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Mechanical Engineering, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Neurosurgery, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States); Department of Computer Science, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States) and Toshiba Stroke Research Center, SUNY at Buffalo, 3435 Main Street, Buffalo, New York 14214 (United States)

    2010-02-15

    Purpose: Cone-beam rotational angiography (CBRA) is widely used in the modern clinical settings. In a number of procedures, the area of interest is often considerably smaller than the field of view (FOV) of the detector, subjecting the patient to potentially unnecessary x-ray dose. The authors therefore propose a filter-based method to reduce the dose in the regions of low interest, while supplying high image quality in the region of interest (ROI). Methods: For such procedures, the authors propose a method of filtered region of interest (FROI)-CBRA. In the authors' approach, a gadolinium filter with a circular central opening is placed into the x-ray beam during image acquisition. The central region is imaged with high contrast, while peripheral regions are subjected to a substantial lower intensity and dose through beam filtering. The resulting images contain a high contrast/intensity ROI, as well as a low contrast/intensity peripheral region, and a transition region in between. To equalize the two regions' intensities, the first projection of the acquisition is performed with and without the filter in place. The equalization relationship, based on Beer's law, is established through linear regression using corresponding filtered and nonfiltered data. The transition region is equalized based on radial profiles. Results: Evaluations in 2D and 3D show no visible difference between conventional FROI-CBRA projection images and reconstructions in the ROI. CNR evaluations show similar image quality in the ROI, with a reduced CNR in the reconstructed peripheral region. In all filtered projection images, the scatter fraction inside the ROI was reduced. Theoretical and experimental dose evaluations show a considerable dose reduction; using a ROI half the original FOV reduces the dose by 60% for the filter thickness of 1.29 mm. Conclusions: These results indicate the potential of FROI-CBRA to reduce the dose to the patient while supplying the physician with

  3. Adjustable hollow-cone output x-ray beam from an ellipsoidal monocapillary with a pinhole and a beam stop.

    Science.gov (United States)

    Sun, Xue-Peng; Liu, Zhi-Gou; Yi, Long-Tao; Sun, Wei-Yun; Li, Fang-Zou; Jiang, Bo-Wen; Ma, Yong-Zhong; Sun, Tian-Xi

    2015-12-10

    A combined shading system (CSS) consisting of a beam stop and a pinhole is proposed to be used between an ellipsoidal monocapillary (EM) and a conventional laboratory x-ray source to obtain an adjustable hollow-cone output beam for different experiments with no need for changing the EM. The CSS can change the incident x-ray beam on the EM by adjusting the position of the beam stop and the pinhole, with the corresponding change of the output beam of the EM. In this study, the adjustable hollow-cone output x-ray beam of an 80-mm-long EM with a CSS was studied in detail with a laboratory Cu x-ray generator with a focal spot diameter of 50 μm. The adjustable range of the focal spot size of the EM was from 8.6 to 58.7 μm. The adjustable range of the gain of the focal spot of the EM was from 0 to 1350. The beam divergence of the hollow-cone output beam of the EM ranged from 6 to 16.75 mrad. The illumination angle of the hollow-cone output beam of the EM ranged from 0 to 5.95 mrad. In addition, the potential application of the proposed adjusting method in testing the performance of the EM is briefly discussed.

  4. Beam hardening correction for a cone-beam CT system and its effect on spatial resolution

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; WEI Long; YU Zhong-Qiang; FU Guo-Tao; SUN Cui-Li; WANG Yan-Fang; WEI Cun-Feng; CAO Da-Quan; QUE Jie-Min; TANG Xiao; SHI Rong-Jian

    2011-01-01

    In this paper,we present a beam hardening correction (BHC) method in three-dimension space for a cone-beam computed tomography (CBCT) system in a mono-material case and investigate its effect on the spatial resolution.Due to the polychromatic character of the X-ray spectrum used,cupping and streak artifacts called beam hardening artifacts arise in the reconstructed CT images,causing reduced image quality.In addition,enhanced edges are introduced in the reconstructed CT images because of the beam hardening effect.The spatial resolution of the CBCT system is calculated from the edge response function (ERF) on different planes in space.Thus,in the CT images with beam hardening artifacts,enhanced ERFs will be extracted to calculate the modulation transfer function (MTF),obtaining a better spatial resolution that deviates from the real value.Reasonable spatial resolution can be obtained after reducing the artifacts.The 10% MTF value and the full width at half maximum (FWHM) of the point spread function with and without BHC are presented.

  5. A reconstruction method for cone-beam differential x-ray phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Velroyen, Astrid; Tan, Renbo; Zhang, Junwei; Chen, Liyuan; Tapfer, Arne; Bech, Martin; Pfeiffer, Franz

    2012-09-10

    Most existing differential phase-contrast computed tomography (DPC-CT) approaches are based on three kinds of scanning geometries, described by parallel-beam, fan-beam and cone-beam. Due to the potential of compact imaging systems with magnified spatial resolution, cone-beam DPC-CT has attracted significant interest. In this paper, we report a reconstruction method based on a back-projection filtration (BPF) algorithm for cone-beam DPC-CT. Due to the differential nature of phase contrast projections, the algorithm restrains from differentiation of the projection data prior to back-projection, unlike BPF algorithms commonly used for absorption-based CT data. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a micro-focus x-ray tube source. Moreover, the numerical simulation and experimental results demonstrate that the proposed method can deal with several classes of truncated cone-beam datasets. We believe that this feature is of particular interest for future medical cone-beam phase-contrast CT imaging applications.

  6. CT thermometry for cone-beam CT guided ablation

    Science.gov (United States)

    DeStefano, Zachary; Abi-Jaoudeh, Nadine; Li, Ming; Wood, Bradford J.; Summers, Ronald M.; Yao, Jianhua

    2016-03-01

    Monitoring temperature during a cone-beam CT (CBCT) guided ablation procedure is important for prevention of over-treatment and under-treatment. In order to accomplish ideal temperature monitoring, a thermometry map must be generated. Previously, this was attempted using CBCT scans of a pig shoulder undergoing ablation.1 We are extending this work by using CBCT scans of real patients and incorporating more processing steps. We register the scans before comparing them due to the movement and deformation of organs. We then automatically locate the needle tip and the ablation zone. We employ a robust change metric due to image noise and artifacts. This change metric takes windows around each pixel and uses an equation inspired by Time Delay Analysis to calculate the error between windows with the assumption that there is an ideal spatial offset. Once the change map is generated, we correlate change data with measured temperature data at the key points in the region. This allows us to transform our change map into a thermal map. This thermal map is then able to provide an estimate as to the size and temperature of the ablation zone. We evaluated our procedure on a data set of 12 patients who had a total of 24 ablation procedures performed. We were able to generate reasonable thermal maps with varying degrees of accuracy. The average error ranged from 2.7 to 16.2 degrees Celsius. In addition to providing estimates of the size of the ablation zone for surgical guidance, 3D visualizations of the ablation zone and needle are also produced.

  7. Sexual dimorphism of foramen magnum using Cone Beam Computed Tomography.

    Science.gov (United States)

    Tambawala, Shahnaz Shabbir; Karjodkar, Freny R; Sansare, Kaustubh; Prakash, Nimish; Dora, Amaresh Chandra

    2016-11-01

    The aim of this study was to evaluate whether the foramen magnum (FM) dimensions could be used for sex determination using the Cone Beam Computed Tomography (CBCT). Two hundred and sixty six CBCT full Field Of View (FOV) scans (111 males and 115 female subjects) of the skull were retrospectively selected and the FM length, width measured on reconstructed axial cross section by two observers using the CS 3D imaging software at a slice thickness of 300 μm and the FM area subsequently calculated using two established formulae by Routal and Teixeira. All data were subjected to descriptive and discriminant functional analysis to validate the expression of sexual dimorphism in the metric parameters of FM. Using the FM dimensions the overall accuracy rate of sex determination was 66.4%. Out of these, 70.3% of males and 62.6% of females were sexed correctly. The best parameter for sex determination was the Area of the FM. In addition, the accuracy rate of sex prediction using the Area dimensions (Teixeira's formula) was 66.4%, same as that of all the four FM parameters used together. This study validates that there is statistically significant expression of sexual differences in the foramen magnum region, which may prove useful and reliable in predicting sex in partial skull remains by discriminant function analysis when other methods tend to be inconclusive. It suggests the reliability, usability and accuracy of CBCT in forensic identification. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  8. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, Anna M., E-mail: anni.sailer@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Schurink, Geert Willem H., E-mail: gwh.schurink@mumc.nl [Maastricht University Medical Centre, Department of Surgery (Netherlands); Wildberger, Joachim E., E-mail: j.wildberger@mumc.nl; Graaf, Rick de, E-mail: r.de.graaf@mumc.nl; Zwam, Willem H. van, E-mail: w.van.zwam@mumc.nl; Haan, Michiel W. de, E-mail: m.de.haan@mumc.nl; Kemerink, Gerrit J., E-mail: gerrit.kemerink@mumc.nl; Jeukens, Cécile R. L. P. N., E-mail: cecile.jeukens@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands)

    2015-02-15

    PurposeTo evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).MethodsThis prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients’ individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.ResultsMean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1–7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients’ weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.ConclusionsMean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.

  9. 3D analytic cone-beam reconstruction for multiaxial CT acquisitions.

    Science.gov (United States)

    Yin, Zhye; De Man, Bruno; Pack, Jed

    2009-01-01

    A conventional 3rd generation Computed Tomography (CT) system with a single circular source trajectory is limited in terms of longitudinal scan coverage since extending the scan coverage beyond 40 mm results in significant cone-beam artifacts. A multiaxial CT acquisition is achieved by combining multiple sequential 3rd generation axial scans or by performing a single axial multisource CT scan with multiple longitudinally offset sources. Data from multiple axial scans or multiple sources provide complementary information. For full-scan acquisitions, we present a window-based 3D analytic cone-beam reconstruction algorithm by tessellating data from neighboring axial datasets. We also show that multi-axial CT acquisition can extend the axial scan coverage while minimizing cone-beam artifacts. For half-scan acquisitions, one cannot take advantage of conjugate rays. We propose a cone-angle dependent weighting approach to combine multi-axial half-scan data. We compute the relative contribution from each axial dataset to each voxel based on the X-ray beam collimation, the respective cone-angles, and the spacing between the axial scans. We present numerical experiments to demonstrate that the proposed techniques successfully reduce cone-beam artifacts at very large volumetric coverage.

  10. Evaluation of positioning errors of the patient using cone beam CT megavoltage; Evaluacion de errores de posicionamiento del paciente mediante Cone Beam CT de megavoltaje

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Ruiz-Zorrilla, J.; Fernandez Leton, J. P.; Zucca Aparicio, D.; Perez Moreno, J. M.; Minambres Moro, A.

    2013-07-01

    Image-guided radiation therapy allows you to assess and fix the positioning of the patient in the treatment unit, thus reducing the uncertainties due to the positioning of the patient. This work assesses errors systematic and errors of randomness from the corrections made to a series of patients of different diseases through a protocol off line of cone beam CT (CBCT) megavoltage. (Author)

  11. Cone-beam CT技术及其在口腔正畸学中的应用进展%Current advance in application of cone-beam CT in orthodontics

    Institute of Scientific and Technical Information of China (English)

    王婷; 厉松

    2011-01-01

    在正畸的诊断治疗过程中,cone-beam CT已广泛应用于口腔界的各个领域,本文旨在对cone-beamCT的原理、特点及其在口腔正畸领域中的应用进行综述,以期增加正畸医师对于Cone-beam CT的理解.

  12. Self-healing of Bessel-like beams with longitudinally dependent cone angles

    CSIR Research Space (South Africa)

    Litvin, I

    2015-09-01

    Full Text Available Bessel beams have been extensively studied, but to date have been created over a finite region inside the laboratory. Recently Bessel-like beams with longitudinally dependent cone angles have been introduced allowing for a potentially infinite quasi...

  13. Exact cone beam reconstruction formulae for functions and their gradients for spherical and flat detectors

    Science.gov (United States)

    Louis, Alfred K.

    2016-11-01

    We derive unified inversion formulae for the cone beam transform similar to the Radon transform. Reinterpreting Grangeat’s formula we find a relation between the Radon transform of the gradient of the searched-for function and a quantity computable from cone beam data. This gives a uniqueness result for the cone beam transform of compactly supported functions under much weaker assumptions than the Tuy-Kirillov condition. Furthermore this relation leads to an exact formula for the direct calculation of derivatives of the density distribution; but here, similar to the classical Radon transform, complete Radon data are needed, hence the Tuy-Kirillov condition has to be imposed. Numerical experiments reported in Hahn B N et al (2013 Meas. Sci. Technol. 24 125601) indicate that these calculations are less corrupted by beam-hardening noise. Finally, we present flat detector versions for these results, which are mathematically less attractive but important for applications.

  14. Benign Prostatic Hyperplasia: Cone-Beam CT in Conjunction with DSA for Identifying Prostatic Arterial Anatomy.

    Science.gov (United States)

    Wang, Mao Qiang; Duan, Feng; Yuan, Kai; Zhang, Guo Dong; Yan, Jieyu; Wang, Yan

    2017-01-01

    Purpose To describe findings in prostatic arteries (PAs) at digital subtraction angiography (DSA) and cone-beam computed tomography (CT) that allow identification of benign prostatic hyperplasia and to determine the value added with the use of cone-beam CT. Materials and Methods This retrospective single-institution study was approved by the institutional review board, and the requirement for written informed consent was waived. From February 2009 to December 2014, a total of 148 patients (mean age ± standard deviation, 70.5 years ± 14.5) underwent DSA of the internal iliac arteries and cone-beam CT with a flat-detector angiographic system before they underwent prostate artery embolization. Both the DSA and cone-beam CT images were evaluated by two interventional radiologists to determine the number of independent PAs and their origins and anastomoses with adjacent arteries. The exact McNemar test was used to compare the detection rate of the PAs and the anastomoses with DSA and with cone-beam CT. Results The PA anatomy was evaluated successfully by means of cone-beam CT in conjunction with DSA in all patients. Of the 296 pelvic sides, 274 (92.6%) had only one PA. The most frequent PA origin was the common gluteal-pudendal trunk with the superior vesicular artery in 118 (37.1%), followed by the anterior division of the internal iliac artery in 99 (31.1%), and the internal pudendal artery in 77 (24.2%) pelvic sides. In 67 (22.6%) pelvic sides, anastomoses to adjacent arteries were documented. The numbers of PA origins and anastomoses, respectively, that could be identified were significantly higher with cone-beam CT (301 of 318 [94.7%] and 65 of 67 [97.0%]) than with DSA (237 [74.5%] and 39 [58.2%], P Cone-beam CT provided essential information that was not available with DSA in 90 of 148 (60.8%) patients. Conclusion Cone-beam CT is a useful adjunctive technique to DSA for identification of the PA anatomy and provides information to help treatment planning during

  15. Actively triggered 4d cone-beam CT acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Fast, Martin F.; Wisotzky, Eric [German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg (Germany); Oelfke, Uwe; Nill, Simeon [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)

    2013-09-15

    Purpose: 4d cone-beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this “after-the-fact” binning approach, however, projections are unevenly distributed over respiratory phases resulting in inefficient utilization of imaging dose. To avoid excess dose in certain respiratory phases, and poor image quality due to a lack of projections in others, the authors have developed a novel 4d CBCT acquisition framework which actively triggers 2d projections based on the forward-predicted position of the tumor.Methods: The forward-prediction of the tumor position was independently established using either (i) an electromagnetic (EM) tracking system based on implanted EM-transponders which act as a surrogate for the tumor position, or (ii) an external motion sensor measuring the chest-wall displacement and correlating this external motion to the phase-shifted diaphragm motion derived from the acquired images. In order to avoid EM-induced artifacts in the imaging detector, the authors devised a simple but effective “Faraday” shielding cage. The authors demonstrated the feasibility of their acquisition strategy by scanning an anthropomorphic lung phantom moving on 1d or 2d sinusoidal trajectories.Results: With both tumor position devices, the authors were able to acquire 4d CBCTs free of motion blurring. For scans based on the EM tracking system, reconstruction artifacts stemming from the presence of the EM-array and the EM-transponders were greatly reduced using newly developed correction algorithms. By tuning the imaging frequency independently for each respiratory phase prior to acquisition, it was possible to harmonize the number of projections over respiratory phases. Depending on the breathing period (3.5 or 5 s) and the gantry rotation time (4 or 5 min), between ∼90 and 145

  16. Iodized oil uptake assessment with cone-beam CT in chemoembolization of small hepatocellular carcinomas

    Institute of Scientific and Technical Information of China (English)

    Ung Bae Jeon; Jun Woo Lee; Ki Seok Choo; Chang Won Kim; Suk Kim; Tae Hong Lee; Yeon Joo Jeong; Dae Hwan Kang

    2009-01-01

    AIM: To evaluate the utility of assessing iodized oil uptake with cone-beam computed tomography (CT) in transarterial chemoembolization (TACE) for small hepatocellular carcinoma (HCC). METHODS: Cone-beam CT provided by a biplane flatpanel detector angiography suite was performed on eighteen patients (sixteen men and two women; 41-76 years; mean age, 58.9 years) directly after TACE for small HCC (26 nodules under 30 mm; mean diameter, 11.9 mm; range, 5-28 mm). The pre-procedural locations of the tumors were evaluated using triphasic multi-detector row helical computed tomography (MDCT). The tumor locations on MDCT and the iodized oil uptake by the tumors were analyzed on cone-beam CT and on spot image directly after the procedures. RESULTS: All lesions on preprocedural MDCT were detected using iodized oil uptake in the lesions on conebeam CT (sensitivity 100%, 26/26). Spot image depicted iodized oil uptake in 22 of the lesions (sensitivity 85%). The degree of iodized oil uptake was overestimated (9%, 2/22) or underestimated (14%, 3/22) on spot image in five nodules compared with that of cone-beam CT. CONCLUSION: Cone-beam CT is a useful and convenient tool for assessing the iodized oil uptake of small hepatic tumors (< 3 cm) directly after TACE.

  17. Three dimensional evaluation of impacted mesiodens using dental cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Ho; Lee, Jae Seo; Yoon, Suk Ja; Kang, Byung Cheol [Chonnam National University School of Medicine, Gwangju (Korea, Republic of)

    2010-09-15

    This study was performed to analyze the position, pattern of impacted mesiodens, and their relationship to the adjacent teeth using Dental cone-beam CT. Sixty-two dental cone-beam CT images with 81 impacted mesiodenses were selected from about 2,298 cone-beam CT images at Chonnam National University Dental Hospital from June 2006 to March 2009. The position, pattern, shape of impacted mesiodenses and their complications were analyzed in cone-beam CT including 3D images. The sex ratio (M : F) was 2.9 : 1. Most of the mesiodenses (87.7%) were located at palatal side to the incisors. 79% of the mesiodenses were conical in shape. 60.5% of the mesiodenses were inverted, 21% normal erupting direction, and 18.5% transverse direction. The complications due to the presence of mesiodenses were none in 43.5%, diastema in 19.4%, tooth displacement in 17.7%, delayed eruption or impaction in 12.9%, tooth rotation in 4.8%, and dentigerous cyst in 1.7%. Dental cone-beam CT images with 3D provided 3-dimensional perception of mesiodens to the neighboring teeth. This results would be helpful for management of the impacted mesiodens.

  18. Comparison of flat-panel detector and image-intensifier detector for cone-beam CT.

    Science.gov (United States)

    Baba, Rika; Konno, Yasutaka; Ueda, Ken; Ikeda, Shigeyuki

    2002-01-01

    We evaluated a flat-panel detector (FPD) (scintillator screen and a-Si photo-sensor array) for use in a cone-beam computed tomography (CT) detector and compared it with an image-intensifier detector (IID). The FPD cone-beam CT system has a higher spatial resolution than the IID system. At equal pixel sizes, the standard deviation of noise intensity of the FPD system is equal to that of the IID system. However, the circuit noise of the FPD must be reduced, especially at low doses. Our evaluations show that the FPD system has a strong potential for use as a cone-beam CT detector because of high-spatial resolution.

  19. Cone Beam CT在牙种植术中应用的临床观察

    Institute of Scientific and Technical Information of China (English)

    李蓓

    2009-01-01

    文章通过对64例拟行牙种植术患者进行Cone Beam CT检查,观察CT影像在牙种植手术适应证评价与手术设计中的作用.与X线曲面断层片及模型观测结果相比,Cone Beam CT影像提供了更直观,更精确的种植区骨条件信息,提高了牙种植手术的效率,牙种植手术无1例失败.Cone Beam CT应用于牙种植术,能够使手术更加安全、高效,具有较高的临床应用价值.

  20. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dongmei; Zhu, Shouping, E-mail: zhusp2009@gmail.com; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin [Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education and School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China)

    2014-11-10

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging.

  1. Cone beam CT findings of retromolar canals: Report of cases and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Sun [Dept. of Dental Hygiene, Eulji University, Seongnam (Korea, Republic of); Park, Chang Seo [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Yonsei University, Seoul (Korea, Republic of)

    2013-12-15

    A retromolar canal is an anatomical variation in the mandible. As it includes the neurovascular bundle, local anesthetic insufficiency can occur, and an injury of the retromolar canal during dental surgery in the mandible may result in excessive bleeding, paresthesia, and traumatic neuroma. Using imaging analysis software, we evaluated the cone-beam computed tomography (CT) images of two Korean patients who presented with retromolar canals. Retromolar canals were detectable on the sagittal and cross-sectional images of cone-beam CT, but not on the panoramic radiographs of the patients. Therefore, the clinician should pay particular attention to the identification of retromolar canals by preoperative radiographic examination, and additional cone beam CT scanning would be recommended.

  2. Tetrahedron-based orthogonal simultaneous scan for cone-beam computed tomography.

    Science.gov (United States)

    Ye, Ivan B; Wang, Ge

    2012-08-01

    In this article, a cone-beam computed tomography scanning mode is designed using four x-ray sources and a spherical sample. The x-ray sources are mounted at the vertices of a regular tetrahedron. On the circumsphere of the tetrahedron, four detection panels are mounted opposite of each vertex. To avoid x-ray interference, the largest half angle of each x-ray cone beam is 27°22', while the radius of the largest ball fully covered by all the cone beams is 0.460, when the radius of the circumsphere is 1. A proposed scanning scheme consists of two rotations about orthogonal axes, such that, each quarter turn provides sufficient data for theoretically exact and stable reconstruction. This design can be used in biomedical or industrial settings, such as when a sequence of reconstructions of an object is desired.

  3. Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model

    Energy Technology Data Exchange (ETDEWEB)

    Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People' s Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)

    2012-01-15

    Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.

  4. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  5. Protocol of image guided off-line using cone beam CT megavoltage; Protocolo de imagen guiada off-line mediante Cone Beam CT de megavoltaje

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Ruiz-Zorrilla, J.; Fernandez Leton, J. P.; Perez Moreno, J. M.; Zucca Aparicio, D.; Minambres Moro, A.

    2013-07-01

    The goal of image guided protocols offline is to reduce systematic errors in positioning of the patient in the treatment unit, being more important than the random errors, since the systematic have one contribution in the margin of the CTV to the PTV. This paper proposes a protocol for image guided offline with the different actions to take with their threshold values evaluated previously by anatomic location in a sample of 474 patients and 4821Cone beam Megavoltaje CT (CBCT). (Author)

  6. 3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

    Science.gov (United States)

    Fu, Jian; Hu, Xinhua; Velroyen, Astrid; Bech, Martin; Jiang, Ming; Pfeiffer, Franz

    2015-01-01

    Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications.

  7. Investigation of respiration induced intra- and inter-fractional tumour motion using a standard Cone Beam CT

    DEFF Research Database (Denmark)

    Gottlieb, Karina Lindberg; Hansen, Christian R; Hansen, Olfred;

    2010-01-01

    To investigate whether a standard Cone beam CT (CBCT) scan can be used to determined the intra- and inter-fractional tumour motion for lung tumours that have infiltrated the mediastinum.......To investigate whether a standard Cone beam CT (CBCT) scan can be used to determined the intra- and inter-fractional tumour motion for lung tumours that have infiltrated the mediastinum....

  8. Micro-cone targets for producing high energy and low divergence particle beams

    Science.gov (United States)

    Le Galloudec, Nathalie

    2013-09-10

    The present invention relates to micro-cone targets for producing high energy and low divergence particle beams. In one embodiment, the micro-cone target includes a substantially cone-shaped body including an outer surface, an inner surface, a generally flat and round, open-ended base, and a tip defining an apex. The cone-shaped body tapers along its length from the generally flat and round, open-ended base to the tip defining the apex. In addition, the outer surface and the inner surface connect the base to the tip, and the tip curves inwardly to define an outer surface that is concave, which is bounded by a rim formed at a juncture where the outer surface meets the tip.

  9. Accuracy assessment of three-dimensional surface reconstructions of teeth from cone beam computed tomography scans

    NARCIS (Netherlands)

    Al-Rawi, B.; Hassan, B.; Vandenberge, B.; Jacobs, R.

    2010-01-01

    The use of three-dimensional (3D) models of the dentition obtained from cone beam computed tomography (CBCT) is becoming increasingly more popular in dentistry. A recent trend is to replace the traditional dental casts with digital CBCT models for diagnosis, treatment planning and simulation. The ac

  10. Time-resolved cardiac cone beam CT using an interventional C-arm system

    NARCIS (Netherlands)

    Schomberg, H.

    2012-01-01

    It is both desirable and challenging to make interventional C-arm systems fit for cardiac cone beam CT. A number of methods towards thisgoal have been proposed, some of which even attempt to generate 4Dimages of the beating heart. A promising candidate of this type, proposed earlier by this author,

  11. Accuracy and repeatability of anthropometric facial measurements using cone beam computed tomography

    NARCIS (Netherlands)

    Fourie, Zacharias; Damstra, Janalt; Gerrits, Peter O.; Ren, Yijin

    2011-01-01

    Objective: The purpose of this study was to determine the accuracy and repeatability of linear anthropometric measurements on the soft tissue surface model generated from cone beam computed tomography scans. Materials and Methods: The study sample consisted of seven cadaver heads. The accuracy and r

  12. Practical limitations of cone-beam computed tomography in 3D cephalometry

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Ren, Yijin

    2011-01-01

    3D cone beam computed tomography (CBCT) images offer a unique and new appreciation of the anatomical structures and underlying anomalies not possible with conventional radiographs. However, in almost all aspects of CBCT imaging, from utilization to application, inherent limitations and pitfalls exis

  13. Cone-beam computed tomography: An inevitable investigation in cleidocranial dysplasia

    Directory of Open Access Journals (Sweden)

    Nandita S Gupta

    2015-01-01

    Full Text Available Cleidocranial dysplasia is a heritable skeletal dysplasia and one of the most common features of this syndrome is multiple impacted supernumerary teeth. Cone-beam computed tomography, the most recent advancement in maxillofacial imaging, provides the clinician to view the morphology of the skull and the dentition in all three dimensions and help in treatment planning for the patient.

  14. State-of-the-art on cone beam CT imaging for preoperative planning of implant placement.

    NARCIS (Netherlands)

    Guerrero, M.E.; Jacobs, R.; Loubele, M.; Schutyser, F.A.C.; Suetens, P.; Steenberghe, D van

    2006-01-01

    Orofacial diagnostic imaging has grown dramatically in recent years. As the use of endosseous implants has revolutionized oral rehabilitation, a specialized technique has become available for the preoperative planning of oral implant placement: cone beam computed tomography (CT). This imaging techno

  15. The outcome of root-canal treatments assessed by cone-beam computed tomography

    NARCIS (Netherlands)

    Liang, Y.H.

    2013-01-01

    In this thesis, in-vivo and ex-vivo methods were utilized to assess the outcome of root canal treatments determined by cone-beam computed tomography (CBCT) and the reliability of the CBCT-findings. CBCT provided useful and reliable information leading to a better understanding of the outcome and fac

  16. Integration of digital dental casts in cone-beam computed tomography scans

    NARCIS (Netherlands)

    Rangel, F.A.; Maal, T.J.J.; Berge, S.J.; Kuijpers-Jagtman, A.M.

    2012-01-01

    Cone-beam computed tomography (CBCT) is widely used in maxillofacial surgery. The CBCT image of the dental arches, however, is of insufficient quality to use in digital planning of orthognathic surgery. Several authors have described methods to integrate digital dental casts into CBCT scans, but all

  17. Diagnosis and decision making in endodontics with the use of cone beam computed tomography

    NARCIS (Netherlands)

    Metska, M.E.

    2014-01-01

    In the current thesis the use of cone beam computed tomography (CBCT) in endodontics has been evaluated within the framework of ex vivo and in vivo studies. The first objective of the thesis was to examine whether CBCT scans can be used for the detection of vertical root fractures in endodontically

  18. Comparison of percutaneous radiologic gastrostomy by using cone beam CT and endoscopic gastrostomy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyun Nyeong; Han, Young Min; Jin, Gong Yong; Choi, Eun Jeong; Song, Ji Soo [Chonbuk National University Hospital and Medical School, Jeonju (Korea, Republic of)

    2014-01-15

    To compare the effectiveness of percutaneous radiologic gastrostomy (PRG) by using cone beam CT and percutaneous endoscopic gastrostomy (PEG). This study retrospectively reviewed 129 patients who underwent PRG (n = 53) and PEG (n = 76) over a 2-years period. The C-arm cone beam CT images were obtained from all PRG patients before the procedure in order to decide the safest accessing routes. The parameters including technical success rates, complication rates and tube migration rates were all analyzed according to statistical methods. The success rate of tube placement was higher in PRG than in PEG (100% to 93%, p = 0.08). Minor complications occurred in 5 patients of the PRG group (10%; 5/53, 3 wound infection, 2 blood oozing), and occurred in 6 patients of PEG group (7.9%; 6/76, 5 wound infection, 1 esophageal ulcer). Major complications occurred only in 5 patients of PEG group (6.6%; 5/76, 1 panperitonitis, 4 buried bumper syndrome). There were no statistical differences of minor and major complication rates in the two groups (respectively, p = 0.759, p = 0.078). Tube migration rate was lower in PRG than PEG group (7.5% vs. 38.2%, p < 0.005). PRG using cone beam CT is the effective and safe method, the cone beam CT provides the safest accessing route during gastrostomy. Less tube migration occurs in the PRG than in PEG.

  19. Coherence Filtering to Enhance the Mandibular Canal in Cone-Beam CT data

    NARCIS (Netherlands)

    Kroon, Dirk-Jan; Slump, Cornelis H.

    2009-01-01

    Segmenting the mandibular canal from cone beam CT data, is difficult due to low edge contrast and high image noise. We introduce 3D coherence filtering as a method to close the interrupted edges and denoise the structure of the mandibular canal. Coherence Filtering is an anisotropic non-linear

  20. Segmentation of the mandibular canal in cone-beam CT data

    NARCIS (Netherlands)

    Kroon, Dirk-Jan

    2011-01-01

    Accurate information about the location of the mandibular canal is essential in case of dental implant surgery. The goal of our research is to find an automatic method which can segment the mandibular canal in Cone-beam CT (CBCT). Mandibular canal segmentation methods in literature using a priori

  1. Point spread function modeling and images restoration for cone-beam CT

    CERN Document Server

    Zhang, Hua; Shi, Yikai; Xu, Zhe

    2014-01-01

    X-ray cone-beam computed tomography (CT) has the notable features such as high efficiency and precision, and is widely used in the fields of medical imaging and industrial non-destructive testing, but the inherent imaging degradation reduces the quality of CT images. Aimed at the problems of projection images degradation and restoration in cone-beam CT, a point spread function (PSF) modeling method is proposed firstly. The general PSF model of cone-beam CT is established, and based on it, the PSF under arbitrary scanning conditions can be calculated directly for projection images restoration without the additional measurement, which greatly improved the application convenience of cone-beam CT. Secondly, a projection images restoration algorithm based on pre-filtering and pre-segmentation is proposed, which can make the edge contours in projection images and slice images clearer after restoration, and control the noise in the equivalent level to the original images. Finally, the experiments verified the feasib...

  2. Incidental findings on cone beam computed tomography scans in cleft lip and palate patients

    NARCIS (Netherlands)

    Kuijpers, Mette A. R.; Pazera, Andrzej; Admiraal, Ronald J.; Berge, Stefaan J.; Vissink, Arjan; Pazera, Pawel

    2014-01-01

    Cone beam computed tomography (CBCT) is frequently used in treatment planning for alveolar bone grafting (ABG) and orthognathic surgery in patients with cleft lip and palate (CLP). CBCT images may depict coincident findings. The aim of this study was to assess the prevalence of incidental findings o

  3. Incidental findings on cone beam computed tomography scans in cleft lip and palate patients

    NARCIS (Netherlands)

    Kuijpers, M.A.R.; Pazera, A.; Admiraal, R.J.C.; Berge, S.J.; Vissink, A.; Pazera, P.

    2014-01-01

    OBJECTIVES: Cone beam computed tomography (CBCT) is frequently used in treatment planning for alveolar bone grafting (ABG) and orthognathic surgery in patients with cleft lip and palate (CLP). CBCT images may depict coincident findings. The aim of this study was to assess the prevalence of incidenta

  4. Cone Beam Computed Tomography-Dawn of A New Imaging Modality in Orthodontics

    Science.gov (United States)

    Mamatha, J; Chaitra, K R; Paul, Renji K; George, Merin; Anitha, J; Khanna, Bharti

    2015-01-01

    Today, we are in a world of innovations, and there are various diagnostics aids that help to take a decision regarding treatment in a well-planned way. Cone beam computed tomography (CBCT) has been a vital tool for imaging diagnostic tool in orthodontics. This article reviews case reports during orthodontic treatment and importance of CBCT during the treatment evaluation. PMID:26225116

  5. Evaluation of web-based instruction for anatomical interpretation in maxillofacial cone beam computed tomography

    NARCIS (Netherlands)

    Al-Rawi, W.T.; Jacobs, R.; Hassan, B.A.; Sanderink, G.; Scarfe, W.C.

    2007-01-01

    Objectives: To evaluate the effectiveness of a web-based instruction in the interpretation of anatomy in images acquired with maxillofacial cone beam CT (CBCT). Methods: An interactive web-based education course for the interpretation of craniofacial CBCT images was recently developed at our institu

  6. AAE and AAOMR Joint Position Statement: Use of Cone Beam Computed Tomography in Endodontics 2015 Update.

    Science.gov (United States)

    2015-10-01

    The following statement was prepared by the Special Committee to Revise the Joint American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology Position on Cone Beam Computed Tomography, and approved by the AAE Board of Directors and AAOMR Executive Council in May 2015. AAE members may reprint this position statement for distribution to patients or referring dentists.

  7. Cone Beam Computed Tomography-Dawn of A New Imaging Modality in Orthodontics

    OpenAIRE

    Mamatha, J; Chaitra, K R; Paul, Renji K; George, Merin; J. Anitha; Khanna, Bharti

    2015-01-01

    Today, we are in a world of innovations, and there are various diagnostics aids that help to take a decision regarding treatment in a well-planned way. Cone beam computed tomography (CBCT) has been a vital tool for imaging diagnostic tool in orthodontics. This article reviews case reports during orthodontic treatment and importance of CBCT during the treatment evaluation.

  8. Calculating nasoseptal flap dimensions : a cadaveric study using cone beam computed tomography

    NARCIS (Netherlands)

    ten Dam, Ellen; Korsten-Meijer, Astrid G. W.; Schepers, Rutger H.; van der Meer, Wicher J.; Gerrits, Peter O.; van der Laan, Bernard F. A. M.; Feijen, Robert A.

    2015-01-01

    We hypothesize that three-dimensional imaging using cone beam computed tomography (CBCT) is suitable for calculating nasoseptal flap (NSF) dimensions. To evaluate our hypothesis, we compared CBCT NSF dimensions with anatomical dissections. The NSF reach and vascularity were studied. In an anatomical

  9. Cone Beam Computed Tomography-Dawn of A New Imaging Modality in Orthodontics.

    Science.gov (United States)

    Mamatha, J; Chaitra, K R; Paul, Renji K; George, Merin; Anitha, J; Khanna, Bharti

    2015-01-01

    Today, we are in a world of innovations, and there are various diagnostics aids that help to take a decision regarding treatment in a well-planned way. Cone beam computed tomography (CBCT) has been a vital tool for imaging diagnostic tool in orthodontics. This article reviews case reports during orthodontic treatment and importance of CBCT during the treatment evaluation.

  10. Evidence supporting the use of cone-beam computed tomography in orthodontics.

    NARCIS (Netherlands)

    Vlijmen, O.J.C. van; Kuijpers, M.A.R.; Berge, S.J.; Schols, J.G.J.H.; Maal, T.J.J.; Breuning, H.; Kuijpers-Jagtman, A.M.

    2012-01-01

    BACKGROUND: The authors conducted a systematic review of cone-beam computed tomography (CBCT) applications in orthodontics and evaluated the level of evidence to determine whether the use of CBCT is justified in orthodontics. TYPES OF STUDIES REVIEWED: The authors identified articles by searching th

  11. Precision of identifying cephalometric landmarks with cone beam computed tomography in vivo

    NARCIS (Netherlands)

    Hassan, B.; Nijkamp, P.; Verheij, H.; Tairie, J.; Vink, C.; van der Stelt, P.; van Beek, H.

    2013-01-01

    The study aims were to assess the precision and time required to conduct cephalometric analysis with cone-beam computed tomography (CBCT) in vivo on both three-dimensional (3D) surface models and multi-planar reformations (MPR) images. Datasets from 10 patients scanned with CBCT were used to create

  12. Incidental findings on cone beam computed tomography scans in cleft lip and palate patients

    NARCIS (Netherlands)

    Kuijpers, Mette A. R.; Pazera, Andrzej; Admiraal, Ronald J.; Berge, Stefaan J.; Vissink, Arjan; Pazera, Pawel

    Cone beam computed tomography (CBCT) is frequently used in treatment planning for alveolar bone grafting (ABG) and orthognathic surgery in patients with cleft lip and palate (CLP). CBCT images may depict coincident findings. The aim of this study was to assess the prevalence of incidental findings

  13. Influence of cone beam CT scanning parameters on grey value measurements at an implant site

    NARCIS (Netherlands)

    Parsa, A.; Ibrahim, N.; Hassan, B.; Motroni, A.; van der Stelt, P.; Wismeijer, D.

    2013-01-01

    Objectives: The aim of this study was to determine the grey value variation at the implant site with different scan settings, including field of view (FOV), spatial resolution, number of projections, exposure time and dose selections in two cone beam CT (CBCT) systems and to compare the results with

  14. Evidence supporting the use of cone-beam computed tomography in orthodontics.

    NARCIS (Netherlands)

    Vlijmen, O.J.C. van; Kuijpers, M.A.R.; Berge, S.J.; Schols, J.G.J.H.; Maal, T.J.J.; Breuning, H.; Kuijpers-Jagtman, A.M.

    2012-01-01

    BACKGROUND: The authors conducted a systematic review of cone-beam computed tomography (CBCT) applications in orthodontics and evaluated the level of evidence to determine whether the use of CBCT is justified in orthodontics. TYPES OF STUDIES REVIEWED: The authors identified articles by searching

  15. Contours identification of elements in a cone beam computed tomography for investigating maxillary cysts

    Science.gov (United States)

    Chioran, Doina; Nicoarǎ, Adrian; Roşu, Şerban; Cǎrligeriu, Virgil; Ianeş, Emilia

    2013-10-01

    Digital processing of two-dimensional cone beam computer tomography slicesstarts by identification of the contour of elements within. This paper deals with the collective work of specialists in medicine and applied mathematics in computer science on elaborating and implementation of algorithms in dental 2D imagery.

  16. [Accurate 3D free-form registration between fan-beam CT and cone-beam CT].

    Science.gov (United States)

    Liang, Yueqiang; Xu, Hongbing; Li, Baosheng; Li, Hongsheng; Yang, Fujun

    2012-06-01

    Because the X-ray scatters, the CT numbers in cone-beam CT cannot exactly correspond to the electron densities. This, therefore, results in registration error when the intensity-based registration algorithm is used to register planning fan-beam CT and cone-beam CT. In order to reduce the registration error, we have developed an accurate gradient-based registration algorithm. The gradient-based deformable registration problem is described as a minimization of energy functional. Through the calculus of variations and Gauss-Seidel finite difference method, we derived the iterative formula of the deformable registration. The algorithm was implemented by GPU through OpenCL framework, with which the registration time was greatly reduced. Our experimental results showed that the proposed gradient-based registration algorithm could register more accurately the clinical cone-beam CT and fan-beam CT images compared with the intensity-based algorithm. The GPU-accelerated algorithm meets the real-time requirement in the online adaptive radiotherapy.

  17. Comparison of Swedish and Norwegian Use of Cone-Beam Computed Tomography: a Questionnaire Study

    Directory of Open Access Journals (Sweden)

    Jerker Edén Strindberg

    2015-12-01

    Full Text Available Objectives: Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of cone-beam computed tomography in Sweden with a previous Norwegian study, regarding specifically technical aspects. Material and Methods: The questionnaire contained 45 questions, including 35 comparable questions to Norwegian clinics one year previous. Results were based on inter-comparison of the outcome from each of the two questionnaire studies. Results: Responses rate was 71% in Sweden. There, most of cone-beam computed tomography (CBCT examinations performed by dental nurses, while in Norway by specialists. More than two-thirds of the CBCT units had a scout image function, regularly used in both Sweden (79% and Norway (75%. In Sweden 4% and in Norway 41% of the respondents did not wait for the report from the radiographic specialist before initiating treatment. Conclusions: The bilateral comparison showed an overall similarity between the two countries. The survey gave explicit and important knowledge of the need for education and training of the whole team, since radiation dose to the patient could vary a lot for the same kind of radiographic examination. It is essential to establish quality assurance protocols with defined responsibilities in the team in order to maintain high diagnostic accuracy for all examinations when using cone-beam computed tomography for patient examinations.

  18. Evaluation of the OSC-TV iterative reconstruction algorithm for cone-beam optical CT

    Energy Technology Data Exchange (ETDEWEB)

    Matenine, Dmitri, E-mail: dmitri.matenine.1@ulaval.ca; Mascolo-Fortin, Julia, E-mail: julia.mascolo-fortin.1@ulaval.ca [Département de physique, de génie physique et d’optique, Université Laval, Québec, Québec G1V 0A6 (Canada); Goussard, Yves, E-mail: yves.goussard@polymtl.ca [Département de génie électrique/Institut de génie biomédical, École Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, Québec H3C 3A7 (Canada); Després, Philippe, E-mail: philippe.despres@phy.ulaval.ca [Département de physique, de génie physique et d’optique and Centre de recherche sur le cancer, Université Laval, Québec, Québec G1V 0A6, Canada and Département de radio-oncologie and Centre de recherche du CHU de Québec, Québec, Québec G1R 2J6 (Canada)

    2015-11-15

    Purpose: The present work evaluates an iterative reconstruction approach, namely, the ordered subsets convex (OSC) algorithm with regularization via total variation (TV) minimization in the field of cone-beam optical computed tomography (optical CT). One of the uses of optical CT is gel-based 3D dosimetry for radiation therapy, where it is employed to map dose distributions in radiosensitive gels. Model-based iterative reconstruction may improve optical CT image quality and contribute to a wider use of optical CT in clinical gel dosimetry. Methods: This algorithm was evaluated using experimental data acquired by a cone-beam optical CT system, as well as complementary numerical simulations. A fast GPU implementation of OSC-TV was used to achieve reconstruction times comparable to those of conventional filtered backprojection. Images obtained via OSC-TV were compared with the corresponding filtered backprojections. Spatial resolution and uniformity phantoms were scanned and respective reconstructions were subject to evaluation of the modulation transfer function, image uniformity, and accuracy. The artifacts due to refraction and total signal loss from opaque objects were also studied. Results: The cone-beam optical CT data reconstructions showed that OSC-TV outperforms filtered backprojection in terms of image quality, thanks to a model-based simulation of the photon attenuation process. It was shown to significantly improve the image spatial resolution and reduce image noise. The accuracy of the estimation of linear attenuation coefficients remained similar to that obtained via filtered backprojection. Certain image artifacts due to opaque objects were reduced. Nevertheless, the common artifact due to the gel container walls could not be eliminated. Conclusions: The use of iterative reconstruction improves cone-beam optical CT image quality in many ways. The comparisons between OSC-TV and filtered backprojection presented in this paper demonstrate that OSC-TV can

  19. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2016-04-07

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm(-1). For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm(-1). With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  20. Stray light in cone beam optical computed tomography: II. Reduction using a convergent light source

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2016-04-01

    Optical cone beam computed tomography (CBCT) using a broad beam and CCD camera is a fast method for densitometry of 3D optical gel dosimeters. However, diffuse light sources introduce considerable stray light into the imaging system, leading to underestimation of attenuation coefficients and non-uniformities in CT images unless corrections are applied to each projection image. In this study, the light source of a commercial optical CT scanner is replaced with a convergent cone beam source consisting of almost exclusively image forming primary rays. The convergent source is achieved using a small isotropic source and a Fresnel lens. To characterize stray light effects, full-field cone beam CT imaging is compared to fan beam CT (FBCT) using a 1 cm high fan beam aperture centered on the optic axis of the system. Attenuating liquids are scanned within a large 96 mm diameter uniform phantom and in a small 13.5 mm diameter finger phantom. For the uniform phantom, cone and fan beam CT attenuation coefficients agree within a maximum deviation of (1  ±  2)% between mean values over a wide range from 0.036 to 0.43 cm-1. For the finger phantom, agreement is found with a maximum deviation of (4  ±  2)% between mean values over a range of 0.1-0.47 cm-1. With the convergent source, artifacts associated with refractive index mismatch and vessel optical features are more pronounced. Further optimization of the source size to achieve a balance between quantitative accuracy and artifact reduction should enable practical, accurate 3D dosimetry, avoiding time consuming 3D scatter measurements.

  1. Composite cone-beam filtered backprojection algorithm based on nutating line

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; OU Zong-ying; SU Tie-ming; WANG Feng

    2006-01-01

    The FDK algorithm is the most popular cone beam algorithm in the medical and industrial imaging field.Due to data insufficiency acquired from a circular trajectory,the images reconstructed by the FDK algorithm suffer from the intensity droping with increasing cone angle.To overcome the drawback,a modified FDK algorithm is presented by convert the 1D ramp filtering direction from along the horizontal lines to along the nutating lines based on the result of Turbell.Unlike Turbell's method,there is no need for our algorithm to rebin the cone-beam data into 3D parallel-beam data before reconstructing.Moreover pre-weighting of the projection data is corrected by compensating for the cone angle effect.In addition,another correction term derived from the result of Hu is also induced into our algorithm.The simulation experiments demonstrate that the final algorithm can suppress the intensity drop associated with the FDK algorithm.

  2. Design and development of C-arm based cone-beam CT for image-guided interventions: initial results

    Science.gov (United States)

    Chen, Guang-Hong; Zambelli, Joseph; Nett, Brian E.; Supanich, Mark; Riddell, Cyril; Belanger, Barry; Mistretta, Charles A.

    2006-03-01

    X-ray cone-beam computed tomography (CBCT) is of importance in image-guided intervention (IGI) and image-guided radiation therapy (IGRT). In this paper, we present a cone-beam CT data acquisition system using a GE INNOVA 4100 (GE Healthcare Technologies, Waukesha, Wisconsin) clinical system. This new cone-beam data acquisition mode was developed for research purposes without interfering with any clinical function of the system. It provides us a basic imaging pipeline for more advanced cone-beam data acquisition methods. It also provides us a platform to study and overcome the limiting factors such as cone-beam artifacts and limiting low contrast resolution in current C-arm based cone-beam CT systems. A geometrical calibration method was developed to experimentally determine parameters of the scanning geometry to correct the image reconstruction for geometric non-idealities. Extensive phantom studies and some small animal studies have been conducted to evaluate the performance of our cone-beam CT data acquisition system.

  3. Practical limitations of cone-beam computed tomography in 3D cephalometry%Practical limitations of cone-beam computed tomography in3D cephalometry

    Institute of Scientific and Technical Information of China (English)

    Janalt Damstra; Zacharias Fourie; Yijin Ren

    2011-01-01

    3D cone beam computed tomography (CBCT) images offer a unique and new appreciation of the anatomical structures and underlying anomalies not possible with conventional radiographs.However,in almost all aspects of CBCT imaging,from utilization to application,inherent limitations and pitfalls exist.Importantly,these inherent limitations and pitfalls have practical implications which need to be addressed before the potential of this technology can be fully realized.The purpose of this review was to explore the current limitations and pitfalls associated with CBCT imaging to allow for better and more accurate understanding of the possibilities this imaging modality could offer,particularly pertaining to 3D cephalometry.

  4. Electromagnetic scattering of a vector Bessel beam in the presence of an impedance cone

    KAUST Repository

    Salem, Mohamed

    2013-07-01

    The electromagnetic field scattering of a vector Bessel beam in the presence of an infinite circular cone with an impedance boundary on its surface is considered. The impinging field is normal to the tip of the cone and is expanded in terms of vector spherical wave functions; a Kontorovich-Lebedev (KL) transform is employed to expand the scattered fields. The problem is reduced to a singular integral equation with a variable coefficient of the non-convolution type. The singularities of the spectral function are deduced and representations for the field at the tip of the cone as well as other regions are given together with the conditions of validity of these representations. © 2013 IEEE.

  5. Cone Beam X-ray Luminescence Computed Tomography Based on Bayesian Method.

    Science.gov (United States)

    Zhang, Guanglei; Liu, Fei; Liu, Jie; Luo, Jianwen; Xie, Yaoqin; Bai, Jing; Xing, Lei

    2017-01-01

    X-ray luminescence computed tomography (XLCT), which aims to achieve molecular and functional imaging by X-rays, has recently been proposed as a new imaging modality. Combining the principles of X-ray excitation of luminescence-based probes and optical signal detection, XLCT naturally fuses functional and anatomical images and provides complementary information for a wide range of applications in biomedical research. In order to improve the data acquisition efficiency of previously developed narrow-beam XLCT, a cone beam XLCT (CB-XLCT) mode is adopted here to take advantage of the useful geometric features of cone beam excitation. Practically, a major hurdle in using cone beam X-ray for XLCT is that the inverse problem here is seriously ill-conditioned, hindering us to achieve good image quality. In this paper, we propose a novel Bayesian method to tackle the bottleneck in CB-XLCT reconstruction. The method utilizes a local regularization strategy based on Gaussian Markov random field to mitigate the ill-conditioness of CB-XLCT. An alternating optimization scheme is then used to automatically calculate all the unknown hyperparameters while an iterative coordinate descent algorithm is adopted to reconstruct the image with a voxel-based closed-form solution. Results of numerical simulations and mouse experiments show that the self-adaptive Bayesian method significantly improves the CB-XLCT image quality as compared with conventional methods.

  6. Measurement of breast tissue composition with dual energy cone-beam computed tomography: A postmortem study

    Energy Technology Data Exchange (ETDEWEB)

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee [Department of Radiological Sciences, University of California, Irvine, California 92697 (United States)

    2013-06-15

    Purpose: To investigate the feasibility of a three-material compositional measurement of water, lipid, and protein content of breast tissue with dual kVp cone-beam computed tomography (CT) for diagnostic purposes. Methods: Simulations were performed on a flat panel-based computed tomography system with a dual kVp technique in order to guide the selection of experimental acquisition parameters. The expected errors induced by using the proposed calibration materials were also estimated by simulation. Twenty pairs of postmortem breast samples were imaged with a flat-panel based dual kVp cone-beam CT system, followed by image-based material decomposition using calibration data obtained from a three-material phantom consisting of water, vegetable oil, and polyoxymethylene plastic. The tissue samples were then chemically decomposed into their respective water, lipid, and protein contents after imaging to allow direct comparison with data from dual energy decomposition. Results: Guided by results from simulation, the beam energies for the dual kVp cone-beam CT system were selected to be 50 and 120 kVp with the mean glandular dose divided equally between each exposure. The simulation also suggested that the use of polyoxymethylene as the calibration material for the measurement of pure protein may introduce an error of -11.0%. However, the tissue decomposition experiments, which employed a calibration phantom made out of water, oil, and polyoxymethylene, exhibited strong correlation with data from the chemical analysis. The average root-mean-square percentage error for water, lipid, and protein contents was 3.58% as compared with chemical analysis. Conclusions: The results of this study suggest that the water, lipid, and protein contents can be accurately measured using dual kVp cone-beam CT. The tissue compositional information may improve the sensitivity and specificity for breast cancer diagnosis.

  7. Scatter correction, intermediate view estimation and dose characterization in megavoltage cone-beam CT imaging

    Science.gov (United States)

    Sramek, Benjamin Koerner

    The ability to deliver conformal dose distributions in radiation therapy through intensity modulation and the potential for tumor dose escalation to improve treatment outcome has necessitated an increase in localization accuracy of inter- and intra-fractional patient geometry. Megavoltage cone-beam CT imaging using the treatment beam and onboard electronic portal imaging device is one option currently being studied for implementation in image-guided radiation therapy. However, routine clinical use is predicated upon continued improvements in image quality and patient dose delivered during acquisition. The formal statement of hypothesis for this investigation was that the conformity of planned to delivered dose distributions in image-guided radiation therapy could be further enhanced through the application of kilovoltage scatter correction and intermediate view estimation techniques to megavoltage cone-beam CT imaging, and that normalized dose measurements could be acquired and inter-compared between multiple imaging geometries. The specific aims of this investigation were to: (1) incorporate the Feldkamp, Davis and Kress filtered backprojection algorithm into a program to reconstruct a voxelized linear attenuation coefficient dataset from a set of acquired megavoltage cone-beam CT projections, (2) characterize the effects on megavoltage cone-beam CT image quality resulting from the application of Intermediate View Interpolation and Intermediate View Reprojection techniques to limited-projection datasets, (3) incorporate the Scatter and Primary Estimation from Collimator Shadows (SPECS) algorithm into megavoltage cone-beam CT image reconstruction and determine the set of SPECS parameters which maximize image quality and quantitative accuracy, and (4) evaluate the normalized axial dose distributions received during megavoltage cone-beam CT image acquisition using radiochromic film and thermoluminescent dosimeter measurements in anthropomorphic pelvic and head and

  8. Improved Scatter Correction in X-Ray Cone Beam CT with Moving Beam Stop Array Using Johns' Equation

    CERN Document Server

    Yan, Hao; Tang, Shaojie; Xu, Qiong

    2014-01-01

    In this paper, an improved scatter correction with moving beam stop array (BSA) for x-ray cone beam (CB) CT is proposed. Firstly, correlation between neighboring CB views is deduced based on John's Equation. Then, correlation-based algorithm is presented to complement the incomplete views by using the redundancy (over-determined information) in CB projections. Finally, combining the algorithm with scatter correction method using moving BSA, where part of primary radiation is blocked and incomplete projections are acquired, an improved correction method is proposed. Effectiveness and robustness is validated by Monte Carlo (MC) simulation with EGSnrc on humanoid phantom.

  9. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities.

    Science.gov (United States)

    Lechuga, Lawrence; Weidlich, Georg A

    2016-09-12

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities-fan beam and cone beam-was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient.

  10. [Upper airway's 3D analysis of patients with obstructive sleep apnea using tomographic cone beam].

    Science.gov (United States)

    Bruwier, A; Poirrier, A L; Limme, M; Poirrier, R

    2014-12-01

    The progress of medical imaging over the last decades has led to a better understanding of the upper airway structure in sleep-disordered patients. The Obstructive Sleep Apnea Syndrome (OSA) is attributed to a functional narrowing of the upper airway, particularly of the oropharynx, during sleep. This narrowing is multifactorial. We have shown that in 60% cases, the maxilla (nasal pyramid) seems too narrow. A mandible retroposition may also play a dominant role in 30% of the cases. Both scenarios can be combined. Cone Beam Computed Tomography (CBCT) is a new medical imaging technique that permits to visualize the upper airway with less ionizing radiation than the conventional scanner. To date, only five authors have performed an upper airway's 3D analysis of sleep apnea patients with cone beam. A better understanding of the affected segment of the upper airway should help refine treatment options.

  11. Endodontic applications of cone beam computed tomography: case series and literature review

    Directory of Open Access Journals (Sweden)

    Francesc Abella

    2015-11-01

    Full Text Available Cone beam computed tomography (CBCT is a relatively new method that produces three-dimensional (3D information of the maxillofacial skeleton, including the teeth and their surrounding tissue, with a lower effective radiation dose than traditional CT scans. Specific endodontic applications for CBCT are being identified as the use of this technology becomes more common. CBCT has great potential to become a valuable tool for diagnosing and managing endodontic problems, as well as for assessing root fractures, apical periodontitis, resorptions, perforations, root canal anatomy and the nature of the alveolar bone topography around teeth. This article aims to review cone beam technology and its advantages over CT scans and conventional radiography, to illustrate current and future clinical applications in endodontic practice, and to highlight areas of further research of CBCT in endodontics. Specific case examples illustrate how treatment planning has changed with the images obtained with CBCT technology compared with only periapical radiography.

  12. MR cone-beam CT fusion image overlay for fluoroscopically guided percutaneous biopsies in pediatric patients.

    Science.gov (United States)

    Thakor, Avnesh S; Patel, Premal A; Gu, Richard; Rea, Vanessa; Amaral, Joao; Connolly, Bairbre L

    2016-03-01

    Lesions only visible on magnetic resonance (MR) imaging cannot easily be targeted for image-guided biopsy using ultrasound or X-rays but instead require MR guidance with MR-compatible needles and long procedure times (acquisition of multiple MR sequences). We developed an alternative method for performing these difficult biopsies in a standard interventional suite, by fusing MR with cone-beam CT images. The MR cone-beam CT fusion image is then used as an overlay to guide a biopsy needle to the target area under live fluoroscopic guidance. Advantages of this technique include (i) the ability for it to be performed in a conventional interventional suite, (ii) three-dimensional planning of the needle trajectory using cross-sectional imaging, (iii) real-time fluoroscopic guidance for needle trajectory correction and (iv) targeting within heterogeneous lesions based on MR signal characteristics to maximize the potential biopsy yield.

  13. Cone-Beam Computed Tomography Evaluation of Mental Foramen Variations: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahnaz Sheikhi

    2015-01-01

    Full Text Available Background. Mental foramen is important in surgical operations of premolars because it transfers the mental nerves and vessels. This study evaluated the variations of mental foramen by cone-beam computed tomography among a selected Iranian population. Materials and Methods. A total number of 180 cone-beam computed tomography projections were analyzed in terms of shape, size, direction, and horizontal and vertical positions of mental foramen in the right and left sides. Results. The most common shape was oval, opening direction was posterior-superior, horizontal position was in line with second premolar, and vertical position was apical to the adjacent dental root. The mean of foremen diameter was 3.59 mm. Conclusion. In addition to the most common types of mental foramen, other variations exist, too. Hence, it reflects the significance of preoperative radiographic examinations, especially 3-dimensional images to prevent nerve damage.

  14. A simplified approach for the generation of projection data for cone beam geometry

    Indian Academy of Sciences (India)

    Tushar Roy; P S Sarkar; Amar Sinha

    2011-04-01

    To test a developed reconstruction algorithm for cone beam geometry, whether it is transmission or emission tomography, one needs projection data. Generally, mathematical phantoms are generated in three dimensions and the projection for all rotation angles is calculated. For non-symmetric objects, the process is cumbersome and computation intensive. This paper describes a simple methodology for the generation of projection data for cone beam geometry for both transmission and emission tomographies by knowing the object’s attenuation and/or source spatial distribution details as input. The object details such as internal geometrical distribution are nowhere involved in the projection data calculation. This simple approach uses the pixilated object matrix values in terms of the matrix indices and spatial geometrical coordinates. The projection data of some typical phantoms (generated using this approach) are reconstructed using standard FDK algorithm and Novikov’s inversion formula. Correlation between the original and reconstructed images has been calculated to compare the image quality.

  15. Respiratory correlated cone-beam computed tomography on an isocentric C-arm

    Energy Technology Data Exchange (ETDEWEB)

    Kriminski, Sergey [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Mitschke, Matthias [Siemens Medical Solutions USA, Inc. Oncology Care Systems, Concord, CA 94520 (United States); Sorensen, Stephen [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Wink, Nicole M [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Chow, Phillip E [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Tenn, Steven [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Solberg, Timothy D [Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 (United States); Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095 (United States); University of Nebraska Medical Center, Omaha, NE 68102 (United States)

    2005-11-21

    A methodology for 3D image reconstruction from retrospectively gated cone-beam CT projection data has been developed. A mobile x-ray cone-beam device consisting of an isocentric C-arm equipped with a flat panel detector was used to image a moving phantom. Frames for reconstruction were retrospectively selected from complete datasets based on the known rotation of the C-arm and a signal from a respiratory monitor. Different sizes of gating windows were tested. A numerical criterion for blur on the reconstructed image was suggested. The criterion is based on minimization of an Ising energy function, similar to approaches used in image segmentation or restoration. It is shown that this criterion can be used for the determination of the optimal gating window size. Images reconstructed from the retrospectively gated projection sequences using the optimal gating window data showed a significant improvement compared to images reconstructed from the complete projection datasets.

  16. Respiratory correlated cone-beam computed tomography on an isocentric C-arm

    Science.gov (United States)

    Kriminski, Sergey; Mitschke, Matthias; Sorensen, Stephen; Wink, Nicole M.; Chow, Phillip E.; Tenn, Steven; Solberg, Timothy D.

    2005-11-01

    A methodology for 3D image reconstruction from retrospectively gated cone-beam CT projection data has been developed. A mobile x-ray cone-beam device consisting of an isocentric C-arm equipped with a flat panel detector was used to image a moving phantom. Frames for reconstruction were retrospectively selected from complete datasets based on the known rotation of the C-arm and a signal from a respiratory monitor. Different sizes of gating windows were tested. A numerical criterion for blur on the reconstructed image was suggested. The criterion is based on minimization of an Ising energy function, similar to approaches used in image segmentation or restoration. It is shown that this criterion can be used for the determination of the optimal gating window size. Images reconstructed from the retrospectively gated projection sequences using the optimal gating window data showed a significant improvement compared to images reconstructed from the complete projection datasets.

  17. Prevalence of C-shaped root canal in a Brazilian subpopulation: a cone-beam computed tomography analysis

    National Research Council Canada - National Science Library

    Ladeira, Daniela Brait Silva; Cruz, Adriana Dibo; Freitas, Deborah Queiroz; Almeida, Solange Maria

    2014-01-01

    The aim of this study was to use cone-beam computed tomography (CBCT) images to evaluate the prevalence and configurations of C-shaped canals in permanent mandibular second molars among members of a Brazilian subpopulation...

  18. Diagnostic accuracy of cone beam computed tomography in detection of simulated mandibular condyle erosions

    OpenAIRE

    Shahriar Shahab; Nafiseh Nikkerdar; Maryam Goodarzi; Amin Golshah; Sanaz Sharifi Shooshtari

    2015-01-01

    Introduction: To determine the diagnostic accuracy of cone beam computed tomography (CBCT) in the detection of simulated mandibular condyle erosions. Materials and Methods: Seventeen dry human mandibles were used in this in vitro study. NewTom VG CBCT scanner (New Tom VG, Verona, Veneto region, Italy) was used for the condyles imaging (pre-erosion and post-erosion image). Thirty three lesions were created on the superior (11 cases), anterior (11 cases), and posterior surfaces (11 cases) o...

  19. Assessment of optimal condylar position with cone-beam computed tomography in south Indian female population

    OpenAIRE

    Manjula, W. S.; Faizal Tajir; R.V. Murali; Kishore Kumar, S; Mohammed Nizam

    2015-01-01

    Aim: The purpose of this study was to investigate, the condyle-fossa relationship, in clinically asymptomatic orthodontically untreated south Indian female volunteers, by cone-beam computed tomography (CBCT). Materials and Methods: The study population consisted of 13 clinically symptom-free and orthodontically untreated angle's Class I female subjects with the mean age of 18 years (ranges from 17 years to 20 years). The normal disc position of the 13 subjects was confirmed by history, clinic...

  20. Quantification of organ motion during chemoradiotherapy of rectal cancer using cone-beam computed tomography.

    LENUS (Irish Health Repository)

    Chong, Irene

    2011-11-15

    There has been no previously published data related to the quantification of rectal motion using cone-beam computed tomography (CBCT) during standard conformal long-course chemoradiotherapy. The purpose of the present study was to quantify the interfractional changes in rectal movement and dimensions and rectal and bladder volume using CBCT and to quantify the bony anatomy displacements to calculate the margins required to account for systematic (Σ) and random (σ) setup errors.

  1. Maxillary first molars with six canals confirmed with the aid of cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Tahra Mohammad Al-Habboubi

    2016-01-01

    Full Text Available The maxillary first molar exhibits unpredictable root canal morphology. Different number of root canals has been reported with the aids of new tools. It is very important to clinically detect all canals for better outcome results. The purpose of the present case is to present a case of the maxillary first molar in a Saudi male patient with an anatomical variation of having six root canals that were confirmed with cone-beam computed tomography.

  2. The effect of cone beam CT (CBCT) on therapeutic decision-making in endodontics

    OpenAIRE

    Mota de Almeida, F J; Knutsson, K.; Flygare, Lennart

    2014-01-01

    Objectives: The aim was to assess to what extent cone beam CT (CBCT) used in accordance with current European Commission guidelines in a normal clinical setting has an impact on therapeutic decisions in a population referred for endodontic problems. Methods: The study includes data of consecutively examined patients collected from October 2011 to December 2012. From 2 different endodontic specialist clinics, 57 patients were referred for a CBCT examination using criteria in accordance with cu...

  3. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT

    OpenAIRE

    Sorapong Aootaphao; Saowapak S. Thongvigitmanee; Jartuwat Rajruangrabin; Chalinee Thanasupsombat; Tanapon Srivongsa; Pairash Thajchayapong

    2016-01-01

    Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter ...

  4. Impact of cone-beam computed tomography on implant planning and on prediction of implant size

    OpenAIRE

    Ludmila Assunção de Mello Pedroso; Robson Rodrigues Garcia; José Luiz Rodrigues Leles; Cláudio Rodrigues Leles; Maria Alves Garcia Santos Silva

    2014-01-01

    The aim was to investigate the impact of cone-beam computed tomography (CBCT) on implant planning and on prediction of final implant size. Consecutive patients referred for implant treatment were submitted to clinical examination, panoramic (PAN) radiography and a CBCT exam. Initial planning of implant length and width was assessed based on clinical and PAN exams, and final planning, on CBCT exam to complement diagnosis. The actual dimensions of the implants placed during surgery were compare...

  5. Dental cone beam CT image quality possibly reduced by patient movement.

    Science.gov (United States)

    Donaldson, K; O'Connor, S; Heath, N

    2013-01-01

    Patient artefacts in dental cone beam CT scans can happen for various reasons. These range from artefacts from metal restorations to movement. An audit was carried out in the Glasgow Dental Hospital analysing how many scans showed signs of "motion artefact", and then to assess if there was any correlation between patient age and movement artefacts. Specific age demographics were then analysed to see if these cohorts were at a higher risk of "movement artefacts".

  6. SADMFR guidelines for the use of cone-beam computed tomography/ Digital Volume Tomography

    OpenAIRE

    Dula, Karl; Bornstein, Michael M.; Buser, Daniel; Dagassan-Berndt, Dorothea; Ettlin, Dominik A; Filippi, Andreas; Gabioud, François; Katsaros, Christos; Krastl, Gabriel; Lambrecht, J. Thomas; Lauber, Roland; Luebbers, Heinz-Theo; Pazera, Pawel; Türp, Jens C.

    2014-01-01

    Cone-Beam Computed Tomography (CBCT) has been introduced in 1998. This radiological imaging procedure has been provided for dentistry and is comparable to computed tomography (CT) in medicine. It is expected that CBCT will have the same success in dental diagnostic imaging as computed tomography had in medicine. Just as CT is responsible for a significant rise in radiation dose to the population from medical X-ray diagnostics, CBCT studies will be accompanied by a significant increase of the ...

  7. Dental implants in bilateral bifid canal and compromised interocclusal space using cone beam computerized tomography

    Science.gov (United States)

    Ahmed, Nizar; Arunachalam, Lalitha Tanjore; Jacob, Caroline Annette; Kumar, Suresh Anand

    2016-01-01

    Knowledge of various anatomic landmarks is pivotal for important success. Bifid canals pose a challenge and can lead to difficulties while performing implant surgery in the mandible. Bifid canals can be diagnosed with panoramic radiography and more accurately with cone beam computerized tomography (CBCT). This case report details the placement of the implant in a patient with bilateral bifid canal and compromised interocclusal space, which was successfully treated using CBCT. PMID:27433073

  8. The current status of cone beam computed tomography imaging in orthodontics

    OpenAIRE

    S. Kapila; Conley, R S; Harrell, W E

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assess...

  9. The possible usability of three-dimensional cone beam computed dental tomography in dental research

    Science.gov (United States)

    Yavuz, I.; Rizal, M. F.; Kiswanjaya, B.

    2017-08-01

    The innovations and advantages of three-dimensional cone beam computed dental tomography (3D CBCT) are continually growing for its potential use in dental research. Imaging techniques are important for planning research in dentistry. Newly improved 3D CBCT imaging systems and accessory computer programs have recently been proven effective for use in dental research. The aim of this study is to introduce 3D CBCT and open a window for future research possibilities that should be given attention in dental research.

  10. Assessment of bifid and trifid mandibular canals using cone-beam computed tomography

    OpenAIRE

    2014-01-01

    Purpose To investigate the prevalence of bifid and trifid mandibular canals using cone-beam computed tomography (CBCT) images, and to measure their length, diameter, and angle. Materials and Methods CBCT images of 500 patients, involving 755 hemi-mandibles, were used for this study. The presence and type of bifid mandibular canal was evaluated according to a modified classification of Naitoh et al. Prevalence rates were determined according to age group, gender, and type. Further, their diame...

  11. SPECT reconstruction of combined cone beam and parallel hole collimation with experimental data

    Science.gov (United States)

    Li, Jianying; Jaszczak, Ronald J.; Turkington, Timothy G.; Greer, Kim L.; Coleman, R. Edward

    1993-06-01

    We have developed three methods to combine parallel and cone beam (P & CB) SPECT data using modified Maximum Likelihood-Expectation Maximization (ML-EM) algorithms. The first combination method applies both parallel and cone beam data sets to reconstruct a single intermediate image after each iteration using the ML-EL algorithm. The other two iterative methods combine the intermediate beam (PB) and cone (CB) source estimates to enhance the uniformity of images. These two methods are ad hoc methods. In earlier studies using computer Monte Carlo simulation, we suggested that improved images might be obtained by reconstructing combined P & CB SPECT data. These combined collimation methods are qualitatively evaluated using experimental data. An attenuation compensation is performed by including the effects of attenuation in the transition matrix as a multiplicative factor. The combined P&CB images are compared with CB-only images and the results indicate that the combined P&CB approaches suppress artifacts caused by truncated projections and correct for the distortions of the CB-only images.

  12. [Change in condylar and mandibular morphology in juvenile idiopathic arthritis: cone beam volumetric imaging].

    Science.gov (United States)

    Garagiola, Umberto; Mercatali, Lorenzo; Bellintani, Claudio; Fodor, Attila; Farronato, Giampietro; Lőrincz, Adám

    2013-03-01

    The aim of this study is to show the importance of Cone Beam Computerized Tomography to volumetrically quantify TMJ damage in patients with JIA, measuring condylar and mandibular real volumes. 34 children with temporomandibular involvement by Juvenile Idiopathic Arthritis were observed by Cone Beam Computerized Tomography. 4 were excluded because of several imaging noises. The mandible was isolated from others craniofacial structures; the whole mandibular volume and its components' volumes (condyle, ramus, hemibody, hemisymphysis on right side and on left side) has been calculated by a 3D volume rendering technique. The results show a highly significant statistical difference between affected side volumetric values versus normal side volumetric values above all on condyle region (P < 0.01), while they don't show any statistical differences between right side versus left side. The Cone Beam Computerized Tomography represents a huge improvement in understanding of the condyle and mandibular morphological changes, even in the early stages of the Juvenile Idiopathic Arthritis. The JIA can lead in children to temporomandibular joint damage with facial development and growth alterations.

  13. Marker-free lung tumor trajectory estimation from a cone beam CT sinogram

    Science.gov (United States)

    Hugo, Geoffrey D.; Liang, Jian; Yan, Di

    2010-05-01

    An algorithm was developed to estimate the 3D lung tumor position using the projection data forming a cone beam CT sinogram and a template registration method. A pre-existing respiration-correlated CT image was used to generate templates of the target, which were then registered to the individual cone beam CT projections, and estimates of the target position were made for each projection. The registration search region was constrained based on knowledge of the mean tumor position during the cone beam CT scan acquisition. Several template registration algorithms were compared, including correlation coefficient and robust methods such as block correlation, robust correlation coefficient and robust gradient correlation. Robust registration metrics were found to be less sensitive to occlusions such as overlying tissue and the treatment couch. The mean accuracy of the position estimation was 1.4 mm in phantom with a robust registration algorithm. In two research subjects with peripheral tumors, the mean position and mean target excursion were estimated to within 2.0 mm compared to the results obtained with a '4D' registration of 4D image volumes.

  14. GPU-Based 3D Cone-Beam CT Image Reconstruction for Large Data Volume

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2009-01-01

    Full Text Available Currently, 3D cone-beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed in this paper. This method divides both projection data and reconstructed image volume into subsets according to geometric symmetries in circular cone-beam projection layout, and a fast reconstruction for large data volume can be implemented by packing the subsets of projection data into the RGBA channels of GPU, performing the reconstruction chunk by chunk and combining the individual results in the end. The method is evaluated by reconstructing 3D images from computer-simulation data and real micro-CT data. Our results indicate that the GPU implementation can maintain original precision and speed up the reconstruction process by 110–120 times for circular cone-beam scan, as compared to traditional CPU implementation.

  15. Comparison between multislice and cone-beam computerized tomography in the volumetric assessment of cleft palate.

    Science.gov (United States)

    Albuquerque, Marco Antonio; Gaia, Bruno Felipe; Cavalcanti, Marcelo Gusmão Paraíso

    2011-08-01

    The aim of this study was to determine the applicability of multislice and cone-beam computerized tomography (CT) in the assessment of bone defects in patients with oral clefts. Bone defects were produced in 9 dry skulls to mimic oral clefts. All defects were modeled with wax. The skulls were submitted to multislice and cone-beam CT. Subsequently, physical measurements were obtained by the Archimedes principle of water displacement of wax models. The results demonstrated that multislice and cone-beam CT showed a high efficiency rate and were considered to be effective for volumetric assessment of bone defects. It was also observed that both CT modalities showed excellent results with high reliability in the study of the volume of bone defects, with no difference in performance between them. The clinical applicability of our research has shown these CT modalities to be immediate and direct, and they is important for the diagnosis and therapeutic process of patients with oral cleft. Copyright © 2011 Mosby, Inc. All rights reserved.

  16. Accuracy of measurements of mandibular anatomy in cone beam computed tomography images

    Science.gov (United States)

    Ludlow, John B.; Laster, William Stewart; See, Meit; Bailey, L’Tanya J.; Hershey, H. Garland

    2013-01-01

    Objectives Cone beam computed tomography (CBCT) images of ideally positioned and systematically mispositioned dry skulls were measured using two-dimensional and three-dimensional software measurement techniques. Image measurements were compared with caliper measurements of the skulls. Study design Cone beam computed tomography volumes of 28 skulls in ideal, shifted, and rotated positions were assessed by measuring distances between anatomic points and reference wires by using panoramic reconstructions (two-dimensional) and direct measurements from axial slices (three-dimensional). Differences between caliper measurements on skulls and software measurements in images were assessed with paired t tests and analysis of variance (ANOVA). Results Accuracy of measurement was not significantly affected by alterations in skull position or measurement of right or left sides. For easily visualized orthodontic wires, measurement accuracy was expressed by average errors less than 1.2% for two-dimensional measurement techniques and less than 0.6% for three-dimensional measurement techniques. Anatomic measurements were significantly more variable regardless of measurement technique. Conclusions Both two-dimensional and three-dimensional techniques provide acceptably accurate measurement of mandibular anatomy. Cone beam computed tomography measurement was not significantly influenced by variation in skull orientation during image acquisition. PMID:17395068

  17. Evaluation of the mandibular canal visibility on cone-beam computed tomography images of the mandible.

    Science.gov (United States)

    Shokri, Abbas; Shakibaei, Zahra; Langaroodi, Adineh Javadian; Safaei, Mehran

    2014-05-01

    The mandibular canal (MC) is an important and necessary landmark that should be considered before any surgery in the posterior region of the mandible. This study is aimed to evaluate the visibility and position of the MC in an Iranian population using cone-beam computed tomography. In this cross-sectional study, cone-beam computed tomography images of 69 patients, which were available as soft copies in the archives of the databases in the Department of Oral Radiology at Hamadan University of Medical Sciences (Hamadan, Iran), were analyzed. The visibility, corticalization, and position of the MC were assessed by 2 expert oral radiologists independently. The χ2 test, unpaired t test, and 1-way analysis of variance were used for analysis. The right and left MCs were clearly visible in 89.6% and 84.7% of the cases, respectively. Among 87.5% of cases, the MC was observed simultaneously in 2 sides. Position of the MC in relation to surrounding structures showed lowest asymmetry at the second premolar area. There were no statistically significant difference between sex and the evaluated parameters. Cone-beam computed tomography was successful in most cases in displaying the MC. The areas with most MC visibility in the right and left sides were the second and third molar regions, respectively. This visibility declined forwardly in both sides.

  18. Use of cone beam computed tomography in implant dentistry: current concepts, indications and limitations for clinical practice and research.

    Science.gov (United States)

    Bornstein, Michael M; Horner, Keith; Jacobs, Reinhilde

    2017-02-01

    Diagnostic radiology is an essential component of treatment planning in the field of implant dentistry. This narrative review will present current concepts for the use of cone beam computed tomography imaging, before and after implant placement, in daily clinical practice and research. Guidelines for the selection of three-dimensional imaging will be discussed, and limitations will be highlighted. Current concepts of radiation dose optimization, including novel imaging modalities using low-dose protocols, will be presented. For preoperative cross-sectional imaging, data are still not available which demonstrate that cone beam computed tomography results in fewer intraoperative complications such as nerve damage or bleeding incidents, or that implants inserted using preoperative cone beam computed tomography data sets for planning purposes will exhibit higher survival or success rates. The use of cone beam computed tomography following the insertion of dental implants should be restricted to specific postoperative complications, such as damage of neurovascular structures or postoperative infections in relation to the maxillary sinus. Regarding peri-implantitis, the diagnosis and severity of the disease should be evaluated primarily based on clinical parameters and on radiological findings based on periapical radiographs (two dimensional). The use of cone beam computed tomography scans in clinical research might not yield any evident beneficial effect for the patient included. As many of the cone beam computed tomography scans performed for research have no direct therapeutic consequence, dose optimization measures should be implemented by using appropriate exposure parameters and by reducing the field of view to the actual region of interest.

  19. Cone Beam CT vs. Fan Beam CT: A Comparison of Image Quality and Dose Delivered Between Two Differing CT Imaging Modalities

    Science.gov (United States)

    Weidlich, Georg A.

    2016-01-01

    A comparison of image quality and dose delivered between two differing computed tomography (CT) imaging modalities—fan beam and cone beam—was performed. A literature review of quantitative analyses for various image quality aspects such as uniformity, signal-to-noise ratio, artifact presence, spatial resolution, modulation transfer function (MTF), and low contrast resolution was generated. With these aspects quantified, cone beam computed tomography (CBCT) shows a superior spatial resolution to that of fan beam, while fan beam shows a greater ability to produce clear and anatomically correct images with better soft tissue differentiation. The results indicate that fan beam CT produces superior images to that of on-board imaging (OBI) cone beam CT systems, while providing a considerably less dose to the patient. PMID:27752404

  20. Gambaran densitas kamar pulpa gigi sulung menggunakan cone beam CT-3D (Description of pulp chamber density in deciduous teeth using cone beam CT-3D

    Directory of Open Access Journals (Sweden)

    Herdiyati Y

    2013-06-01

    Full Text Available Background: Dental caries is the most common chronic diseases. Detection of caries is needed, especially on the deciduous teeth. An examination such as radiological examination is essential. The radiographic figures distinguish radiolucent of the crown. Digital radiography cone beam computed tomography (CBCT is able to show a more detailed picture. Purpose: This study was aimed to get value of the density of pulp chamber of caries and non caries deciduous teeth using CBCT radiographs. Methods: The study was conducted by using simple descriptive. The samples were all the data CBCT of pediatric patients aged 7-10 years who visited the Dental Hospital of the Faculty of Dentistry, University of Padjadjaran. The samples were teeth with single and double root. Results: The results showed that the value of the normal pulp density is 422.56 Hu, while the condition of caries decreased becomes -77.89 Hu. Conclusion: The tooth with caries showed a lower density than the non caries/tooth.Latar belakang: Karies gigi merupakan penyakit kronis yang sering terjadi. Deteksi terhadap karies sangat diperlukan terutama pada gigi decidius. Pemeriksaan penunjang berupa pemeriksaan radiologis sangat diperlukan. Secara umum gambaran radiografi dapat membedakan karies berupa gambaran radiolusent pada mahkota. Radiografi digital cone beam computed tomografi (CBCT, merupakan jenis radiografi yang mampu memperlihatkan gambaran yang lebih detail. Tujuan: Penelitian ini bertujuan mendapatkan nilai densitas kamar pulpa gigi sulung yang karies dan non karies menggunakan radiografi CBCT. Metode: Penelitian dilakukan dengan metode simple deskriptif. Sampel penelitian adalah semua data CBCT dari pasien anak berusia 7 - 10 tahun yang berkunjung ke RSGM Fakultas Kedokteran Gigi Universitas Padjadjaran. Gigi yang dianalisa meliputi gigi berakar tunggal dan berakar ganda. Hasil: Hasil penelitian menunjukkan bahwa nilai densitas pulpa normal adalah 422,56 Hu, sedangkan pada kondisi

  1. Investigation of the dose distribution for a cone beam CT system dedicated to breast imaging.

    Science.gov (United States)

    Lanconelli, Nico; Mettivier, Giovanni; Lo Meo, Sergio; Russo, Paolo

    2013-06-01

    Cone-beam breast Computed Tomography (bCT) is an X-ray imaging technique for breast cancer diagnosis, in principle capable of delivering a much more homogeneous dose spatial pattern to the breast volume than conventional mammography, at dose levels comparable to two-view mammography. We present an investigation of the three-dimensional dose distribution for a cone-beam CT system dedicated to breast imaging. We employed Monte Carlo simulations for estimating the dose deposited within a breast phantom having a hemiellipsoidal shape placed on a cylinder of 3.5 cm thickness that simulates the chest wall. This phantom represents a pendulant breast in a bCT exam with the average diameter at chest wall, assumed to correspond to a 5-cm-thick compressed breast in mammography. The phantom is irradiated in a circular orbit with an X-ray cone beam selected from four different techniques: 50, 60, 70, and 80 kVp from a tube with tungsten anode, 1.8 mm Al inherent filtration and additional filtration of 0.2 mm Cu. Using the Monte Carlo code GEANT4 we simulated a system similar to the experimental apparatus available in our lab. Simulations were performed at a constant free-in-air air kerma at the isocenter (1 μGy); the corresponding total number of photon histories per scan was 288 million at 80 kVp. We found that the more energetic beams provide a more uniform dose distribution than at low energy: the 50 kVp beam presents a frequency distribution of absorbed dose values with a coefficient of variation almost double than that for the 80 kVp beam. This is confirmed by the analysis of the relative dose profiles along the radial (i.e. parallel to the "chest wall") and longitudinal (i.e. from "chest wall" to "nipple") directions. Maximum radial deviations are on the order of 25% for the 80 kVp beam, whereas for the 50 kVp beam variations around 43% were observed, with the lowest dose values being found along the central longitudinal axis of the phantom. Copyright © 2012

  2. Maxillary first molar with 7 root canals diagnosed using cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Evaldo Rodrigues

    2017-02-01

    Full Text Available Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This case report describes the importance of cone beam computed tomographyic (CBCT imaging during endodontic treatment. A 23 year old woman was referred by her general dental practitioner with the chief complaint of spontaneous pain in her right posterior maxilla. From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis was made and endodontic treatment was suggested to the patient. The patient underwent CBCT examination, and CBCT scan slices revealed seven canals: three mesiobuccal (MB1, MB2, and MB3, two distobuccal (DB1 and DB2, and two palatal (P1 and P2. Canals were successfully treated with reciprocating files and filled using single-cone filling technique. Precise knowledge of root canal morphology and its variation is important during root canal treatment. CBCT examination is an excellent tool for identifying and managing these complex root canal systems.

  3. Maxillary first molar with 7 root canals diagnosed using cone-beam computed tomography

    Science.gov (United States)

    Rodrigues, Evaldo; Braitt, Antônio Henrique; Galvão, Bruno Ferraz

    2017-01-01

    Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This case report describes the importance of cone beam computed tomographyic (CBCT) imaging during endodontic treatment. A 23 year old woman was referred by her general dental practitioner with the chief complaint of spontaneous pain in her right posterior maxilla. From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis was made and endodontic treatment was suggested to the patient. The patient underwent CBCT examination, and CBCT scan slices revealed seven canals: three mesiobuccal (MB1, MB2, and MB3), two distobuccal (DB1 and DB2), and two palatal (P1 and P2). Canals were successfully treated with reciprocating files and filled using single-cone filling technique. Precise knowledge of root canal morphology and its variation is important during root canal treatment. CBCT examination is an excellent tool for identifying and managing these complex root canal systems.

  4. Modulation transfer function determination using the edge technique for cone-beam micro-CT

    Science.gov (United States)

    Rong, Junyan; Liu, Wenlei; Gao, Peng; Liao, Qimei; Lu, Hongbing

    2016-03-01

    Evaluating spatial resolution is an essential work for cone-beam computed tomography (CBCT) manufacturers, prototype designers or equipment users. To investigate the cross-sectional spatial resolution for different transaxial slices with CBCT, the slanted edge technique with a 3D slanted edge phantom are proposed and implemented on a prototype cone-beam micro-CT. Three transaxial slices with different cone angles are under investigation. An over-sampled edge response function (ERF) is firstly generated from the intensity of the slightly tiled air to plastic edge in each row of the transaxial reconstruction image. Then the oversampled ESF is binned and smoothed. The derivative of the binned and smoothed ERF gives the line spread function (LSF). At last the presampled modulation transfer function (MTF) is calculated by taking the modulus of the Fourier transform of the LSF. The spatial resolution is quantified with the spatial frequencies at 10% MTF level and full-width-half-maximum (FWHM) value. The spatial frequencies at 10% of MTFs are 3.1+/-0.08mm-1, 3.0+/-0.05mm-1, and 3.2+/-0.04mm-1 for the three transaxial slices at cone angles of 3.8°, 0°, and -3.8° respectively. The corresponding FWHMs are 252.8μm, 261.7μm and 253.6μm. Results indicate that cross-sectional spatial resolution has no much differences when transaxial slices being 3.8° away from z=0 plane for the prototype conebeam micro-CT.

  5. Three-Dimensional Reconstruction from Cone-Beam Projections for Flat and Curved Detectors: Reconstruction Method Development.

    Science.gov (United States)

    Hu, Hui

    This dissertation is principally concerned with improving the performance of a prototype image-intensifier -based cone-beam volume computed tomography system by removing or partially removing two of its restricting factors, namely, the inaccuracy of current cone-beam reconstruction algorithm and the image distortion associated with the curved detecting surface of the image intensifier. To improve the accuracy of cone-beam reconstruction, first, the currently most accurate and computationally efficient cone-beam reconstruction method, the Feldkamp algorithm, is investigated by studying the relation of an original unknown function with its Feldkamp estimate. From this study, a partial knowledge on the unknown function can be derived in the Fourier domain from its Feldkamp estimate. Then, based on the Gerchberg-Papoulis algorithm, a modified iterative algorithm efficiently incorporating the Fourier knowledge as well as the a priori spatial knowledge on the unknown function is devised and tested to improve the cone-beam reconstruction accuracy by postprocessing the Feldkamp estimate. Two methods are developed to remove the distortion associated with the curved surface of image intensifier. A calibrating method based on a rubber-sheet remapping is designed and implemented. As an alternative, the curvature can be considered in the reconstruction algorithm. As an initial effort along this direction, a generalized convolution -backprojection reconstruction algorithm for fan-beam and any circular detector arrays is derived and studied.

  6. Minimal residual cone-beam reconstruction with attenuation correction in SPECT

    Science.gov (United States)

    La, Valérie; Grangeat, Pierre

    1998-04-01

    This paper presents an iterative method based on the minimal residual algorithm for tomographic attenuation compensated reconstruction from attenuated cone-beam projections given the attenuation distribution. Unlike conjugate-gradient based reconstruction techniques, the proposed minimal residual based algorithm solves directly a quasisymmetric linear system, which is a preconditioned system. Thus it avoids the use of normal equations, which improves the convergence rate. Two main contributions are introduced. First, a regularization method is derived for quasisymmetric problems, based on a Tikhonov-Phillips regularization applied to the factorization of the symmetric part of the system matrix. This regularization is made spatially adaptive to avoid smoothing the region of interest. Second, our existing reconstruction algorithm for attenuation correction in parallel-beam geometry is extended to cone-beam geometry. A circular orbit is considered. Two preconditioning operators are proposed: the first one is Grangeat's inversion formula and the second one is Feldkamp's inversion formula. Experimental results obtained on simulated data are presented and the shadow zone effect on attenuated data is illustrated.

  7. Scattering-compensated cone beam x-ray luminescence computed tomography

    Science.gov (United States)

    Gao, Peng; Rong, Junyan; Pu, Huangsheng; Liu, Wenlei; Liao, Qimei; Lu, Hongbing

    2016-04-01

    X-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging with x-ray. It is a dual modality imaging technique based on the principle that some nanophosphors can emit near-infrared (NIR) light when excited by x-rays. The x-ray scattering effect is a great issue in both CT and XLCT reconstruction. It has been shown that if the scattering effect compensated, the reconstruction average relative error can be reduced from 40% to 12% in the in the pencil beam XLCT. However, the scattering effect in the cone beam XLCT has not been proved. To verify and reduce the scattering effect, we proposed scattering-compensated cone beam x-ray luminescence computed tomography using an added leading to prevent the spare x-ray outside the irradiated phantom in order to decrease the scattering effect. Phantom experiments of two tubes filled with Y2O3:Eu3+ indicated that the proposed method could reduce the scattering by a degree of 30% and can reduce the location error from 1.8mm to 1.2mm. Hence, the proposed method was feasible to the general case and actual experiments and it is easy to implement.

  8. Study of effective dose of various protocols in equipment cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Soares, M. R.; Maia, A. F. [Universidade Federale de Sergipe, Departamento de Fisica, Cidade Universitaria Prof. Jose Aloisio de Campos, Marechal Rondon s/n, Jardim Rosa Elze, 49-100000 Sao Cristovao, Sergipe (Brazil); Batista, W. O. [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho, Salvador, 40301015 Bahia (Brazil); Caldas, L. V. E.; Lara, P. A., E-mail: mrs2206@gmail.com [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    Currently the cone beam computed tomography is widely used in various procedures of dental radiology. Although the doses values associated with the procedures of cone beam CT are low compared to typical values associated with dental radiology procedure in multi slices CT. However can be high compared to typical values of other techniques commonly used in dental radiology. The present scenario is a very wide range of designs of equipment and, consequently, lack of uniformity in all parameters associated with x-ray generation and geometry. In this context, this study aimed to evaluate and calculate the absorbed dose in organs and tissues relevant and estimate effective dose for different protocols with different geometries of exposure in five cone beam CT equipment. For this, a female Alderson anthropomorphic phantom, manufactured by Radiology Support Devices was used. The phantom was irradiated with 26 dosimeters LiF: Mg, Ti (TLD-100), inserted in organs and tissues along the layers forming the head and neck of the phantom. The equipment used, in this present assessment, was: i-CAT Classical, Kodak 9000 3D, Gendex GXCB 500, Sirona Orthophos X G 3D and Planmeca Pro Max 3D. The effective doses were be determined by the ICRP 103 weighting factors. The values were between 7.0 and 111.5 micro Sv, confirming the broad dose range expected due to the diversity of equipment and protocols used in each equipment. The values of effective dose per Fov size were: between 7 and 51.2 micro Sv for located Fov; between 17.6 and 52.0 micro Sv for medium Fov; and between 11.5 and 43.1 micro Sv to large Fov (maxillofacial). In obtaining the effective dose the measurements highlighted a relevance contribution of dose absorbed by the remaining organs (36%), Salivary glands (30%), thyroid (12%) and bone marrow (12%). (Author)

  9. Phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography

    Science.gov (United States)

    Ludlow, John B.; Walker, Cameron

    2013-01-01

    Introduction Increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern with the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. Methods Effective doses resulting from various combinations of field size, and field location comparing child and adult anthropomorphic phantoms using the recently introduced i-CAT FLX cone-beam computed tomography unit were measured with Optical Stimulated Dosimetry using previously validated protocols. Scan protocols included High Resolution (360° rotation, 600 image frames, 120 kVp, 5 mA, 7.4 sec), Standard (360°, 300 frames, 120 kVp, 5 mA, 3.7 sec), QuickScan (180°, 160 frames, 120 kVp, 5 mA, 2 sec) and QuickScan+ (180°, 160 frames, 90 kVp, 3 mA, 2 sec). Contrast-to-noise ratio (CNR) was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. Results Child phantom doses were on average 36% greater than Adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than Standard protocols for child (p=0.0167) and adult (p=0.0055) phantoms. 13×16 cm cephalometric fields of view ranged from 11–85 μSv in the adult phantom and 18–120 μSv in the child for QuickScan+ and Standard protocols respectively. CNR was reduced by approximately 2/3rds comparing QuickScan+ to Standard exposure parameters. Conclusions QuickScan+ effective doses are comparable to conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off may be acceptable for certain diagnostic tasks such as interim assessment of treatment results. PMID:24286904

  10. A multiscale filter for noise reduction of low-dose cone beam projections.

    Science.gov (United States)

    Yao, Weiguang; Farr, Jonathan B

    2015-08-21

    The Poisson or compound Poisson process governs the randomness of photon fluence in cone beam computed tomography (CBCT) imaging systems. The probability density function depends on the mean (noiseless) of the fluence at a certain detector. This dependence indicates the natural requirement of multiscale filters to smooth noise while preserving structures of the imaged object on the low-dose cone beam projection. In this work, we used a Gaussian filter, exp(-x2/2σ(2)(f)) as the multiscale filter to de-noise the low-dose cone beam projections. We analytically obtained the expression of σ(f), which represents the scale of the filter, by minimizing local noise-to-signal ratio. We analytically derived the variance of residual noise from the Poisson or compound Poisson processes after Gaussian filtering. From the derived analytical form of the variance of residual noise, optimal σ(2)(f)) is proved to be proportional to the noiseless fluence and modulated by local structure strength expressed as the linear fitting error of the structure. A strategy was used to obtain the reliable linear fitting error: smoothing the projection along the longitudinal direction to calculate the linear fitting error along the lateral direction and vice versa. The performance of our multiscale filter was examined on low-dose cone beam projections of a Catphan phantom and a head-and-neck patient. After performing the filter on the Catphan phantom projections scanned with pulse time 4 ms, the number of visible line pairs was similar to that scanned with 16 ms, and the contrast-to-noise ratio of the inserts was higher than that scanned with 16 ms about 64% in average. For the simulated head-and-neck patient projections with pulse time 4 ms, the visibility of soft tissue structures in the patient was comparable to that scanned with 20 ms. The image processing took less than 0.5 s per projection with 1024   ×   768 pixels.

  11. Feasibility study of phase-contrast cone beam CT imaging systems

    Science.gov (United States)

    Cai, Weixing

    Attenuation-based x-ray imaging techniques have been developed for many decades. One of the state-of-the-art imaging modalities is the cone beam computed tomography (CBCT) that efficiently scans an object and reproduces high-resolution and isotropic three-dimensional images of it. However, attenuation-based imaging shows a limitation in soft tissue imaging where the absorption contrast is low. Recently several phase-contrast techniques have been developed that are expected to improve low-contrast details by using the phase information of the object. The idea of this thesis is to incorporate the phase-contrast techniques into the current cone beam CT systems to combine the advantages of both phase-contrast imaging and CBCT. From a practical view of medical imaging, two phase-contrast cone beam CT systems are proposed by using the in-line phase-contrast technique and the differential phase-contrast technique, respectively. An in-line phase-contrast image is a Fresnel diffraction pattern in the near field. The image is edge-enhanced, and for soft tissues it is possible to retrieve the phase projection from a single in-line image. Therefore, this technique can be utilized in either of two methods. The first method is to produce edge-enhanced reconstruction images of the attenuation coefficient, and the second is to reconstruct the phase coefficient using the retrieved phase projections. In order to investigate this modality, computer simulations were performed for both working modes. The results using the in-line phase-contrast technique demonstrate superior image quality than that of the attenuation-based technique. A bench-top in-line PC-CBCT system was designed and constructed on top of an optical table, and a simple phantom was imaged and reconstructed using both modes to validate the principle of the proposed imaging scheme. The grating-based differential phase-contrast technique is able to produce the first derivative of phase projections using the principle of

  12. Florid cemento-osseous dysplasia: A rare case report evaluated with cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Eren Yildirim

    2016-01-01

    Full Text Available A 29-year-old systemically healthy female patient presented to our department. Cone-beam computed tomographic images showed multiple well-defined sclerotic masses with radiolucent border in both right and left molar regions of the mandible. These sclerotic masses were surrounded by a thin radiolucent border. We diagnosed the present pathology as florid cemento-osseous dysplasia and decided to follow the patient without taking biopsy. For the patient, who did not have any clinical complaints, radiographic followupis recommended twice a year. The responsibility of the dentist is to ensure the follow-up of the diagnosed patients and take necessary measures for preventing the infections.

  13. Patient radiation dose and protection from cone-beam computed tomography

    OpenAIRE

    Li,Gang

    2013-01-01

    After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from 19 µSv to 1073 µSv and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply...

  14. Clinical applications of cone beam computed tomography in endodontics: A comprehensive review.

    Science.gov (United States)

    Cohenca, Nestor; Shemesh, Hagay

    2015-09-01

    The use of cone beam computed tomography (CBCT) in endodontics has been extensively reported in the literature. Compared with the traditional spiral computed tomography, limited field of view (FOV) CBCT results in a fraction of the effective absorbed dose of radiation. The purpose of this manuscript is to review the application and advantages associated with advanced endodontic problems and complications, while reducing radiation exposure during complex endodontic procedures. The benefits of the added diagnostic information provided by intraoperative CBCT images in select cases justify the risk associated with the limited level of radiation exposure.

  15. History of imaging in orthodontics from Broadbent to cone-beam computed tomography.

    Science.gov (United States)

    Hans, Mark G; Palomo, J Martin; Valiathan, Manish

    2015-12-01

    The history of imaging and orthodontics is a story of technology informing biology. Advances in imaging changed our thinking as our understanding of craniofacial growth and the impact of orthodontic treatment deepened. This article traces the history of imaging in orthodontics from the invention of the cephalometer by B. Holly Broadbent in 1930 to the introduction of low-cost, low-radiation-dose cone-beam computed tomography imaging in 2015. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  16. Cone-beam computed tomography: Time to move from ALARA to ALADA

    Energy Technology Data Exchange (ETDEWEB)

    Jaju, Prashant P.; Jaju, Sushma P. [Rishiraj College of Dental Sciences and Research Centre, Bhopa(Indonesia)

    2015-12-15

    Cone-beam computed tomography (CBCT) is routinely recommended for dental diagnosis and treatment planning. CBCT exposes patients to less radiation than does conventional CT. Still, lack of proper education among dentists and specialists is resulting in improper referral for CBCT. In addition, aiming to generate high-quality images, operators may increase the radiation dose, which can expose the patient to unnecessary risk. This letter advocates appropriate radiation dosing during CBCT to the benefit of both patients and dentists, and supports moving from the concept of 'as low as reasonably achievable' (ALARA) to 'as low as diagnostically acceptable' (ALADA.

  17. Conservative Management of Type III Dens in Dente Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    K Pradeep

    2012-01-01

    Full Text Available Dens in dente, also known as dens invaginatus, dilated composite odontoma, or deep foramen caecum, is a developmental malformation that usually affects maxillary incisor teeth, particularly lateral incisors. It may occur in teeth anywhere within the jaws, other locations are comparatively rare. It can occur within both the crown and the root, although crown invaginations are more common. The use of cone beam computed tomography (CBCT is very helpful in endodontic diagnosis of complex anatomic variations. In this case we demonstrate the use of CBCT in the evaluation and endodontic management of a Type III dens in dente (Oehler′s Type III.

  18. Florid cemento-osseous dysplasia: A rare case report evaluated with cone-beam computed tomography.

    Science.gov (United States)

    Yildirim, Eren; Bağlar, Serdar; Ciftci, Mehmet Ertugrul; Ozcan, Erdal

    2016-01-01

    A 29-year-old systemically healthy female patient presented to our department. Cone-beam computed tomographic images showed multiple well-defined sclerotic masses with radiolucent border in both right and left molar regions of the mandible. These sclerotic masses were surrounded by a thin radiolucent border. We diagnosed the present pathology as florid cemento-osseous dysplasia and decided to follow the patient without taking biopsy. For the patient, who did not have any clinical complaints, radiographic followupis recommended twice a year. The responsibility of the dentist is to ensure the follow-up of the diagnosed patients and take necessary measures for preventing the infections.

  19. Clinical applications of cone beam computed tomography in endodontics: A comprehensive review.

    Science.gov (United States)

    Cohenca, Nestor; Shemesh, Hagay

    2015-06-01

    Cone beam computed tomography (CBCT) is a new technology that produces three-dimensional (3D) digital imaging at reduced cost and less radiation for the patient than traditional CT scans. It also delivers faster and easier image acquisition. By providing a 3D representation of the maxillofacial tissues in a cost- and dose-efficient manner, a better preoperative assessment can be obtained for diagnosis and treatment. This comprehensive review presents current applications of CBCT in endodontics. Specific case examples illustrate the difference in treatment planning with traditional periapical radiography versus CBCT technology.

  20. Cone beam computed tomography aided diagnosis and treatment of endodontic cases: Critical analysis

    Institute of Scientific and Technical Information of China (English)

    Funda Y?lmaz; K?van? Kamburoglu; Naz Yakar Yeta; Meltem Dartar ?ztan

    2016-01-01

    Although intraoral radiographs still remain the imaging method of choice for the evaluation of endodontic patients, in recent years, the utilization of cone beam computed tomography(CBCT) in endodontics showed a significant jump. This case series presentation shows the importance of CBCT aided diagnosis and treatment of complex endodontic cases such as; root resorption, missed extra canal, fusion, oblique root fracture, nondiagnosed periapical pathology and horizontal root fracture. CBCT may be a useful diagnostic method in several endodontic cases where intraoral radiography and clinical examination alone are unable to provide sufficient information.

  1. A multiscale filter for noise reduction of low-dose cone beam projections

    Science.gov (United States)

    Yao, Weiguang; Farr, Jonathan B.

    2015-08-01

    The Poisson or compound Poisson process governs the randomness of photon fluence in cone beam computed tomography (CBCT) imaging systems. The probability density function depends on the mean (noiseless) of the fluence at a certain detector. This dependence indicates the natural requirement of multiscale filters to smooth noise while preserving structures of the imaged object on the low-dose cone beam projection. In this work, we used a Gaussian filter, \\text{exp}≤ft(-{{x}2}/2σ f2\\right) as the multiscale filter to de-noise the low-dose cone beam projections. We analytically obtained the expression of {σf} , which represents the scale of the filter, by minimizing local noise-to-signal ratio. We analytically derived the variance of residual noise from the Poisson or compound Poisson processes after Gaussian filtering. From the derived analytical form of the variance of residual noise, optimal σ f2 is proved to be proportional to the noiseless fluence and modulated by local structure strength expressed as the linear fitting error of the structure. A strategy was used to obtain the reliable linear fitting error: smoothing the projection along the longitudinal direction to calculate the linear fitting error along the lateral direction and vice versa. The performance of our multiscale filter was examined on low-dose cone beam projections of a Catphan phantom and a head-and-neck patient. After performing the filter on the Catphan phantom projections scanned with pulse time 4 ms, the number of visible line pairs was similar to that scanned with 16 ms, and the contrast-to-noise ratio of the inserts was higher than that scanned with 16 ms about 64% in average. For the simulated head-and-neck patient projections with pulse time 4 ms, the visibility of soft tissue structures in the patient was comparable to that scanned with 20 ms. The image processing took less than 0.5 s per projection with 1024   ×   768 pixels.

  2. Automated volume of interest delineation and rendering of cone beam CT images in interventional cardiology

    Science.gov (United States)

    Lorenz, Cristian; Schäfer, Dirk; Eshuis, Peter; Carroll, John; Grass, Michael

    2012-02-01

    Interventional C-arm systems allow the efficient acquisition of 3D cone beam CT images. They can be used for intervention planning, navigation, and outcome assessment. We present a fast and completely automated volume of interest (VOI) delineation for cardiac interventions, covering the whole visceral cavity including mediastinum and lungs but leaving out rib-cage and spine. The problem is addressed in a model based approach. The procedure has been evaluated on 22 patient cases and achieves an average surface error below 2mm. The method is able to cope with varying image intensities, varying truncations due to the limited reconstruction volume, and partially with heavy metal and motion artifacts.

  3. [Radiographic evaluation of cone-beam computed tomography for oral implants: maxillary sinus].

    Science.gov (United States)

    Wang, Hu

    2015-08-01

    Cone-beam computed tomography (CBCT) has an important function in understanding implant operations. CBCT can be used to evaluate the basic condition of implant site before implant operation and decide whether it is suitable for implanting. CBCT also ensures whether the direction of implant and the operation method are satisfactory. CBCT can be used pre- or post-operation as long as the case involves the maxillary sinus. Clinical implant cases using CBCT were introduced to evaluate the maxillary sinus pre- or post-operation.

  4. La tomografía computarizada cone beam en la ortodoncia, ortopedia facial y funcional

    OpenAIRE

    Roque-Torres,Gina D.; Meneses-López, Abraham; Norberto Bóscolo, Frab; De Almeida, Solange María; HAITER NETO Francisco

    2015-01-01

    La Tomografía Computarizada Cone Beam (TCCB) es una tecnología en rápido desarrollo que proporciona imágenes de alta resolución espacial del complejo craneofacial en tres dimensiones (3D). Durante la última década, el número de publicaciones relacionadas a la TCCB en la literatura se ha incrementado de manera significativa, pero la cuestión fundamental es si esta tecnología conduce a mejores resultados. La TCCB y su aplicación en la ortodoncia es muy importante ya que esta nueva tecnología va...

  5. A service for monitoring the quality of intraoperative cone beam CT images

    Directory of Open Access Journals (Sweden)

    Heckel Frank

    2016-09-01

    Full Text Available In recent years, operating rooms (ORs have transformed into integrated operating rooms, where devices are able to communicate, exchange data, or even steer and control each other. However, image data processing is commonly done by dedicated workstations for specific clinical use-cases. In this paper, we propose a concept for a dynamic service component for image data processing on the example of automatic image quality assessment (AQUA of intraoperative cone beam computed tomography (CBCT images. The service is build using the Open Surgical Communication Protocol (OSCP and the standard for Digital Imaging and Communications in Medicine (DICOM. We have validated the proposed concept in an integrated demonstrator OR.

  6. Role of cone beam computed tomography in the prompt diagnosis of a nasopalatine duct cyst

    Directory of Open Access Journals (Sweden)

    Sapna Panjwani

    2014-01-01

    Full Text Available The nasopalatine duct cyst (NPDC is the most common of all the developmental, epithelial, and non-odontogenic cysts of the maxilla, believed to originate from the epithelial remnants of the nasopalatine duct. Typically, the lesion is asymptomatic and is detected accidentally on a radiograph. The definite diagnosis must be based on the clinical, radiological, and histopathological findings. Frequently misdiagnosed, the NPDC is not rare. The motive of reporting an entity that is not very rare is that the lesion is mostly misdiagnosed, and to emphasize the importance of cone-beam computed tomography (CBCT in the diagnosis and optimized treatment planning of NPDCs.

  7. Scattering correction based on regularization de-convolution for Cone-Beam CT

    OpenAIRE

    Xie, Shi-peng; Yan, Rui-ju

    2016-01-01

    In Cone-Beam CT (CBCT) imaging systems, the scattering phenomenon has a significant impact on the reconstructed image and is a long-lasting research topic on CBCT. In this paper, we propose a simple, novel and fast approach for mitigating scatter artifacts and increasing the image contrast in CBCT, belonging to the category of convolution-based method in which the projected data is de-convolved with a convolution kernel. A key step in this method is how to determine the convolution kernel. Co...

  8. Should cavitation in proximal surfaces be reported in cone beam computed tomography examination?

    DEFF Research Database (Denmark)

    Sansare, K; Singh, D; Sontakke, S

    2014-01-01

    Aim: A clinical study was done to assess the clinical diagnostic accuracy of cone beam computed tomography (CBCT) in detecting proximal cavitated carious lesions in order to determine whether cavitation should be reported when a CBCT examination is available. Materials and Methods: 79 adjacent...... proximal surfaces without restorations in permanent teeth were examined. Patients suspected to have carious lesions after a visual clinical and a bitewing examination participated in a CBCT examination (Kodak 9000 3D, 5 × 3.7 cm field of view, voxel size 0.07 mm). Ethical approval and informed consent were...

  9. Enhancement of breast calcification visualization and detection using a modified PG method in Cone Beam Breast CT.

    Science.gov (United States)

    Liu, Jiangkun; Ning, Ruola; Cai, Weixing; Benitez, Ricardo Betancourt

    2012-01-01

    Cone Beam Breast CT is a promising diagnostic modality in breast imaging. Its isotropic 3D spatial resolution enhances the characterization of micro-calcifications in breasts that might not be easily distinguishable in mammography. However, due to dose level considerations, it is beneficial to further enhance the visualization of calcifications in Cone Beam Breast CT images that might be masked by noise. In this work, the Papoulis-Gerchberg method was modified and implemented in Cone Beam Breast CT images to improve the visualization and detectability of calcifications. First, the PG method was modified and applied to the projections acquired during the scanning process; its effects on the reconstructed images were analyzed by measuring the Modulation Transfer Function and the Noise Power Spectrum. Second, Cone Beam Breast CT images acquired at different dose levels were pre-processed using this technique to enhance the visualization of calcification. Finally, a computer-aided diagnostic algorithm was utilized to evaluate the efficacy of this method to improve calcification detectability. The results demonstrated that this technique can effectively improve image quality by improving the Modulation Transfer Function with a minor increase in noise level. Consequently, the visualization and detectability of calcifications were improved in Cone Beam Breast CT images. This technique was also proved to be useful in reducing the x-ray dose without degrading visualization and detectability of calcifications.

  10. Assessment of protocols in cone beam CT with symmetric and asymmetric beam using effective dose and P{sub ka}

    Energy Technology Data Exchange (ETDEWEB)

    Batista, W. O.; Linhares de O, M. V. [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho, Salvador, 40301015 Bahia (Brazil); Soares, M. R.; Maia, A. F. [Universidade Federal de Sergipe, Departamento de Fisica, Cidade Universitaria Prof. Jose Aloisio de Campos, Marechal Rondon s/n, Jardim Rosa Elze, 49-100000 Sao Cristovao, Sergipe (Brazil); Caldas, L. V. E., E-mail: wilsonottobatista@gmail.com [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The cone beam CT is an emerging technology in dental radiology with significant differences the point of view of design technology between the various manufacturers on the world market. This study aims to evaluate and compare protocols with similar purposes in a cone beam CT scanner using TLDs and air kerma - area product (P{sub ka}) as kerma index. Measurements were performed on two protocols used to obtain the image the maxilla-mandible in equipment Gendex GXCB 500: Protocol [GX1] extended diameter and asymmetric beam (14 cm x 8.5 cm - maxilla / mandible) and protocol [GX2] symmetrical beam (8.5 cm x 8.5 cm - maxillary / mandible). Was used LiF dosimeters (TLD 100) inserted into a female anthropomorphic phantom manufactured by Radiology Support Devices. For all protocols evaluated the value of P{sub ka} using a meter Diamentor E2 and PTW system Radcal Rapidose. The results obtained for Effective Dose / P{sub ka} these measurements were separated by protocol image. Protocol [GX1]: 44.5 μSv/478 mGy cm{sup 2}; protocol [GX2]: 54.8 μSv/507 mGy cm{sup 2}. These values indicate that the relationship between the diameter of the image acquired in the protocol [GX1] and the diameter of the image in the protocol [GX2] is equal to 1.65, the Effective Dose for the first protocol has lower value at 18%. P{sub ka} values reveal very similar results between the two protocols, although, common sense leads to the interpretation that imaging protocols with field of view (Fov) of large diameters imply high values of effective dose when compared to small diameters. However, in this particular case, this is not true due to the asymmetrical beam technology. Conclude that for the cases where the scanner uses asymmetric beam to obtain images with large diameters that cover the entire face there are advantages from the point of view of reducing the exposure of patients with respect to the use of symmetrical beam and / or to Fov images with a smaller diameter. (Author)

  11. Reconstruction-plane-dependent weighted FDK algorithm for cone beam volumetric CT

    Science.gov (United States)

    Tang, Xiangyang; Hsieh, Jiang

    2005-04-01

    The original FDK algorithm has been extensively employed in medical and industrial imaging applications. With an increased cone angle, cone beam (CB) artifacts in images reconstructed by the original FDK algorithm deteriorate, since the circular trajectory does not satisfy the so-called data sufficiency condition (DSC). A few "circular plus" trajectories have been proposed in the past to reduce CB artifacts by meeting the DSC. However, the circular trajectory has distinct advantages over other scanning trajectories in practical CT imaging, such as cardiac, vascular and perfusion applications. In addition to looking into the DSC, another insight into the CB artifacts of the original FDK algorithm is the inconsistency between conjugate rays that are 180° apart in view angle. The inconsistence between conjugate rays is pixel dependent, i.e., it varies dramatically over pixels within the image plane to be reconstructed. However, the original FDK algorithm treats all conjugate rays equally, resulting in CB artifacts that can be avoided if appropriate view weighting strategy is exercised. In this paper, a modified FDK algorithm is proposed, along with an experimental evaluation and verification, in which the helical body phantom and a humanoid head phantom scanned by a volumetric CT (64 x 0.625 mm) are utilized. Without extra trajectories supplemental to the circular trajectory, the modified FDK algorithm applies reconstruction-plane-dependent view weighting on projection data before 3D backprojection, which reduces the inconsistency between conjugate rays by suppressing the contribution of one of the conjugate rays with a larger cone angle. Both computer-simulated and real phantom studies show that, up to a moderate cone angle, the CB artifacts can be substantially suppressed by the modified FDK algorithm, while advantages of the original FDK algorithm, such as the filtered backprojection algorithm structure, 1D ramp filtering, and data manipulation efficiency, can be

  12. Simulation of Cone Beam CT System Based on Monte Carlo Method

    CERN Document Server

    Wang, Yu; Cao, Ruifen; Hu, Liqin; Li, Bingbing

    2014-01-01

    Adaptive Radiation Therapy (ART) was developed based on Image-guided Radiation Therapy (IGRT) and it is the trend of photon radiation therapy. To get a better use of Cone Beam CT (CBCT) images for ART, the CBCT system model was established based on Monte Carlo program and validated against the measurement. The BEAMnrc program was adopted to the KV x-ray tube. Both IOURCE-13 and ISOURCE-24 were chosen to simulate the path of beam particles. The measured Percentage Depth Dose (PDD) and lateral dose profiles under 1cm water were compared with the dose calculated by DOSXYZnrc program. The calculated PDD was better than 1% within the depth of 10cm. More than 85% points of calculated lateral dose profiles was within 2%. The correct CBCT system model helps to improve CBCT image quality for dose verification in ART and assess the CBCT image concomitant dose risk.

  13. Patient dose and image quality from mega-voltage cone beam computed tomography imaging.

    Science.gov (United States)

    Gayou, Olivier; Parda, David S; Johnson, Mark; Miften, Moyed

    2007-02-01

    The evolution of ever more conformal radiation delivery techniques makes the subject of accurate localization of increasing importance in radiotherapy. Several systems can be utilized including kilo-voltage and mega-voltage cone-beam computed tomography (MV-CBCT), CT on rail or helical tomography. One of the attractive aspects of mega-voltage cone-beam CT is that it uses the therapy beam along with an electronic portal imaging device to image the patient prior to the delivery of treatment. However, the use of a photon beam energy in the mega-voltage range for volumetric imaging degrades the image quality and increases the patient radiation dose. To optimize image quality and patient dose in MV-CBCT imaging procedures, a series of dose measurements in cylindrical and anthropomorphic phantoms using an ionization chamber, radiographic films, and thermoluminescent dosimeters was performed. Furthermore, the dependence of the contrast to noise ratio and spatial resolution of the image upon the dose delivered for a 20-cm-diam cylindrical phantom was evaluated. Depending on the anatomical site and patient thickness, we found that the minimum dose deposited in the irradiated volume was 5-9 cGy and the maximum dose was between 9 and 17 cGy for our clinical MV-CBCT imaging protocols. Results also demonstrated that for high contrast areas such as bony anatomy, low doses are sufficient for image registration and visualization of the three-dimensional boundaries between soft tissue and bony structures. However, as the difference in tissue density decreased, the dose required to identify soft tissue boundaries increased. Finally, the dose delivered by MV-CBCT was simulated using a treatment planning system (TPS), thereby allowing the incorporation of MV-CBCT dose in the treatment planning process. The TPS-calculated doses agreed well with measurements for a wide range of imaging protocols.

  14. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Zimmermann, S. J.; Rowshanfarzad, P.; Ebert, M. A.

    2015-01-01

    radiation isocentre prior to routine use of the cone-beam CT system. The isocentre determination method used in the XVI software is not available to users. The aim of this work is to perform an independent evaluation of the Elekta XVI 4.5 software for isocentre verification with focus on the robustness......Purpose/Objective: Most modern radiotherapy treatments are based on cone-beam CT images to ensure precise positioning of the patient relative to the linac. This requires alignment of the cone-beam CT system to the linac MV radiation isocentre. Therefore, it is important to precisely localize the MV......) and the radiation field centre (RFC) is calculated. A software package was developed for accurate calculation of the linac isocentre position. This requires precise determination of the position of the ball bearing and the RFC. Results: Data were acquired for 6 MV, 18 MV and flattening filter free (FFF) 6 MV FFF...

  15. Few-view and limited-angle cone-beam megavoltage CT for breast localization in radiation therapy

    Science.gov (United States)

    Yu, Lifeng; Pan, Xiaochuan; Pelizzari, Charles A.; Martel, Mary

    2004-05-01

    In radiation therapy for breast cancer treatment, information about the external (skin) and internal (lung) boundaries is highly useful for determining the relative locations of the target and lung. In this work, we investigate the feasibility of tomographic reconstruction from few-view and limited-angle cone-beam projections acquired in radiation therapy unit for obtaining critical boundary information. From the few-view and limited-angle projections acquired directly in the treatment machine with an amorphous silicon electronic portal imaging device (EPID), We compared and evaluated the performance of the conventional cone-beam FDK algorithm and an iterative algorithm based upon the maximum-likelihood method for transmission tomography (ML-TR). Preliminary results demonstrated that the ML-TR algorithm is more promising than is the cone-beam FDK algorithm. Useful boundary information for breast localization can be obtained with very few projections in a limited angle range from the reconstruction of ML-TR algorithm.

  16. Direct aneurysm sac catheterization and embolization of an enlarging internal iliac aneurysm using cone-beam CT

    Science.gov (United States)

    Merchant, Monish; Shah, Rohan; Resnick, Scott

    2015-01-01

    Since cone-beam computed tomography (CT) has been adapted for use with a C-arm system it has brought volumetric CT capabilities in the interventional suite. Although cone-beam CT image resolution is far inferior to that generated by traditional CT scanners, the system offers the ability to place an access needle into position under tomographic guidance and use the access to immediately begin a fluoroscopic procedure without moving the patient. We describe a case of a “jailed” enlarging internal iliac artery aneurysm secondary to abdominal aortic aneurysm repair, in which direct percutaneous puncture of the internal iliac artery aneurysm sac was performed under cone-beam CT guidance. PMID:25858522

  17. Analytic image reconstruction from partial data for a single-scan cone-beam CT with scatter correction

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jonghwan; Pua, Rizza; Cho, Seungryong, E-mail: scho@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Insoo; Han, Bumsoo [EB Tech, Co., Ltd., 550 Yongsan-dong, Yuseong-gu, Daejeon 305-500 (Korea, Republic of)

    2015-11-15

    Purpose: A beam-blocker composed of multiple strips is a useful gadget for scatter correction and/or for dose reduction in cone-beam CT (CBCT). However, the use of such a beam-blocker would yield cone-beam data that can be challenging for accurate image reconstruction from a single scan in the filtered-backprojection framework. The focus of the work was to develop an analytic image reconstruction method for CBCT that can be directly applied to partially blocked cone-beam data in conjunction with the scatter correction. Methods: The authors developed a rebinned backprojection-filteration (BPF) algorithm for reconstructing images from the partially blocked cone-beam data in a circular scan. The authors also proposed a beam-blocking geometry considering data redundancy such that an efficient scatter estimate can be acquired and sufficient data for BPF image reconstruction can be secured at the same time from a single scan without using any blocker motion. Additionally, scatter correction method and noise reduction scheme have been developed. The authors have performed both simulation and experimental studies to validate the rebinned BPF algorithm for image reconstruction from partially blocked cone-beam data. Quantitative evaluations of the reconstructed image quality were performed in the experimental studies. Results: The simulation study revealed that the developed reconstruction algorithm successfully reconstructs the images from the partial cone-beam data. In the experimental study, the proposed method effectively corrected for the scatter in each projection and reconstructed scatter-corrected images from a single scan. Reduction of cupping artifacts and an enhancement of the image contrast have been demonstrated. The image contrast has increased by a factor of about 2, and the image accuracy in terms of root-mean-square-error with respect to the fan-beam CT image has increased by more than 30%. Conclusions: The authors have successfully demonstrated that the

  18. Assessment of simulated mandibular condyle bone lesions by cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Alexandre Perez; Perrella, Andreia; Arita, Emiko Saito; Pereira, Marlene Fenyo Soeiro de Matos; Cavalcanti, Marcelo de Gusmao Paraiso, E-mail: alexperez34@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Odontologia. Dept. de Estomatologia

    2010-10-15

    There are many limitations to image acquisition, using conventional radiography, of the temporomandibular joint (TMJ) region. The Computed Tomography (CT) scan is a better option, due to its higher accuracy, for purposes of diagnosis, surgical planning and treatment of bone injuries. The aim of the present study was to analyze two protocols of cone beam computed tomography for the evaluation of simulated mandibular condyle bone lesions. Spherical lesions were simulated in 30 dry mandibular condyles, using dentist drills and drill bits sizes 1, 3 and 6. Each of the mandibular condyles was submitted to cone beam computed tomography (CBCT) using two protocols: axial, coronal and sagittal multiplanar reconstruction (MPR); and sagittal plus coronal slices throughout the longitudinal axis of the mandibular condyles. For these protocols, 2 observers analyzed the CBCT images independently, regarding the presence or not of injuries. Only one of the observers, however, performed on 2 different occasions. The results were compared to the gold standard, evaluating the percentage of agreement, degree of accuracy of CBCT protocols and observers' examination. The z test was used for the statistical analysis. The results showed there were no statistically significant differences between the 2 protocols. There was greater difficulty in the assessment of small-size simulated lesions (drill no.1). From the results of this study, it can be concluded that CBCT is an accurate tool for analyzing mandibular condyle bone lesions, with the MPR protocol showing slightly better results than the sagittal plus coronal slices throughout the longitudinal axis. (author)

  19. Augmented reality and cone beam CT guidance for transoral robotic surgery.

    Science.gov (United States)

    Liu, Wen P; Richmon, Jeremy D; Sorger, Jonathan M; Azizian, Mahdi; Taylor, Russell H

    2015-09-01

    In transoral robotic surgery preoperative image data do not reflect large deformations of the operative workspace from perioperative setup. To address this challenge, in this study we explore image guidance with cone beam computed tomographic angiography to guide the dissection of critical vascular landmarks and resection of base-of-tongue neoplasms with adequate margins for transoral robotic surgery. We identify critical vascular landmarks from perioperative c-arm imaging to augment the stereoscopic view of a da Vinci si robot in addition to incorporating visual feedback from relative tool positions. Experiments resecting base-of-tongue mock tumors were conducted on a series of ex vivo and in vivo animal models comparing the proposed workflow for video augmentation to standard non-augmented practice and alternative, fluoroscopy-based image guidance. Accurate identification of registered augmented critical anatomy during controlled arterial dissection and en bloc mock tumor resection was possible with the augmented reality system. The proposed image-guided robotic system also achieved improved resection ratios of mock tumor margins (1.00) when compared to control scenarios (0.0) and alternative methods of image guidance (0.58). The experimental results show the feasibility of the proposed workflow and advantages of cone beam computed tomography image guidance through video augmentation of the primary stereo endoscopy as compared to control and alternative navigation methods.

  20. Differences between panoramic and Cone Beam-CT in the surgical evaluation of lower third molars

    Science.gov (United States)

    Rodriguez y Baena, Ruggero; Beltrami, Riccardo; Tagliabo, Angelo; Rizzo, Silvana

    2017-01-01

    Background The aim of this study was to evaluate the ability to identify the contiguity between the root of the mandibular third molar and the mandibular canal (MC) in panoramic radiographs compared with Cone Beam-CT. Material and Methods Panoramic radiographs of 326 third molars and CBCT radiographs of 86 cases indicated for surgery and considered at risk were evaluated. The following signs were assessed in panoramic radiographs as risk factors: radiolucent band, loss of MC border, change in MC direction, MC narrowing, root narrowing, root deviation, bifid apex, superimposition, and contact between the root third molar and the MC. Results Radiographic signs associated with absence of MC cortical bone are: radiolucent band, loss of MC border, change in MC direction, and superimposition. The number of risk factors was significantly increased with an increasing depth of inclusion. CBCT revealed a significant association between the absence of MC cortical bone and a lingual or interradicular position of the MC. Conclusions In cases in which panoramic radiographs do not exclude contiguity between the MC and tooth, careful assessment the signs and risks on CBCT radiographs is indicated for proper identification of the relationships between anatomic structures. Key words:Panoramic radiography, Cone-Beam computed tomography, third molar, mandibular nerve. PMID:28210446

  1. Initial Experience with a Cone-beam Breast Computed Tomography-guided Biopsy System

    Science.gov (United States)

    Seifert, Posy J; Morgan, Renee C; Conover, David L; Arieno, Andrea L

    2017-01-01

    Objective: To evaluate our initial experience with a cone-beam breast computed tomography (BCT)-guided breast biopsy system for lesion retrieval in phantom studies for use with a cone-beam BCT imaging system. Materials and Methods: Under the Institutional Review Board approval, a phantom biopsy study was performed using a dedicated BCT-guided biopsy system. Fifteen biopsies were performed on each of the small, medium, and large anthropomorphic breast phantoms with both BCT and stereotactic guidance for comparison. Each set of the 45 phantoms contained masses and calcification clusters of varying sizes. Data included mass/calcium retrieval rate and dose and length of procedure time for phantom studies. Results: Phantom mass and calcium retrieval rate were 100% for BCT and stereotactic biopsy. BCT dose for small and medium breast phantoms was found to be equivalent to or less than the corresponding stereotactic approach. Stereotactic-guided biopsy dose was 34.2 and 62.5 mGy for small and medium breast phantoms, respectively. BCT-guided biopsy dose was 15.4 and 30.0 mGy for small and medium breast phantoms, respectively. Both computed tomography biopsy and stereotactic biopsy study time ranged from 10 to 20 min. Conclusion: Initial experience with a BCT-guided biopsy system has shown to be comparable to stereotactic biopsy in phantom studies with equivalent or decreased dose. PMID:28217404

  2. A denoising algorithm for projection measurements in cone-beam computed tomography.

    Science.gov (United States)

    Karimi, Davood; Ward, Rabab

    2016-02-01

    The ability to reduce the radiation dose in computed tomography (CT) is limited by the excessive quantum noise present in the projection measurements. Sinogram denoising is, therefore, an essential step towards reconstructing high-quality images, especially in low-dose CT. Effective denoising requires accurate modeling of the photon statistics and of the prior knowledge about the characteristics of the projection measurements. This paper proposes an algorithm for denoising low-dose sinograms in cone-beam CT. The proposed algorithm is based on minimizing a cost function that includes a measurement consistency term and two regularizations in terms of the gradient and the Hessian of the sinogram. This choice of the regularization is motivated by the nature of CT projections. We use a split Bregman algorithm to minimize the proposed cost function. We apply the algorithm on simulated and real cone-beam projections and compare the results with another algorithm based on bilateral filtering. Our experiments with simulated and real data demonstrate the effectiveness of the proposed algorithm. Denoising of the projections with the proposed algorithm leads to a significant reduction of the noise in the reconstructed images without oversmoothing the edges or introducing artifacts.

  3. Assessment of simulated mandibular condyle bone lesions by cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Alexandre Perez Marques

    2010-12-01

    Full Text Available There are many limitations to image acquisition, using conventional radiography, of the temporomandibular joint (TMJ region. The Computed Tomography (CT scan is a better option, due to its higher accuracy, for purposes of diagnosis, surgical planning and treatment of bone injuries. The aim of the present study was to analyze two protocols of cone beam computed tomography for the evaluation of simulated mandibular condyle bone lesions. Spherical lesions were simulated in 30 dry mandibular condyles, using dentist drills and drill bits sizes 1, 3 and 6. Each of the mandibular condyles was submitted to cone beam computed tomography (CBCT using two protocols: 1 axial, coronal and sagittal multiplanar reconstruction (MPR; and 2 sagittal plus coronal slices throughout the longitudinal axis of the mandibular condyles. For these protocols, 2 observers analyzed the CBCT images independently, regarding the presence or not of injuries. Only one of the observers, however, performed on 2 different occasions. The results were compared to the gold standard, evaluating the percentage of agreement, degree of accuracy of CBCT protocols and observers' examination. The z test was used for the statistical analysis. The results showed there were no statistically significant differences between the 2 protocols. There was greater difficulty in the assessment of small-size simulated lesions (drill # 1. From the results of this study, it can be concluded that CBCT is an accurate tool for analyzing mandibular condyle bone lesions, with the MPR protocol showing slightly better results than the sagittal plus coronal slices throughout the longitudinal axis.

  4. Ring artifacts removal via spatial sparse representation in cone beam CT

    Science.gov (United States)

    Li, Zhongyuan; Li, Guang; Sun, Yi; Luo, Shouhua

    2016-03-01

    This paper is about the ring artifacts removal method in cone beam CT. Cone beam CT images often suffer from disturbance of ring artifacts which caused by the non-uniform responses of the elements in detectors. Conventional ring artifacts removal methods focus on the correlation of the elements and the ring artifacts' structural characteristics in either sinogram domain or cross-section image. The challenge in the conventional methods is how to distinguish the artifacts from the intrinsic structures; hence they often give rise to the blurred image results due to over processing. In this paper, we investigate the characteristics of the ring artifacts in spatial space, different from the continuous essence of 3D texture feature of the scanned objects, the ring artifacts are displayed discontinuously in spatial space, specifically along z-axis. Thus we can easily recognize the ring artifacts in spatial space than in cross-section. As a result, we choose dictionary representation for ring artifacts removal due to its high sensitivity to structural information. We verified our theory both in spatial space and coronal-section, the experimental results demonstrate that our methods can remove the artifacts efficiently while maintaining image details.

  5. Superimposition of 3-dimensional cone-beam computed tomography models of growing patients

    Science.gov (United States)

    Cevidanes, Lucia H. C.; Heymann, Gavin; Cornelis, Marie A.; DeClerck, Hugo J.; Tulloch, J. F. Camilla

    2009-01-01

    Introduction The objective of this study was to evaluate a new method for superimposition of 3-dimensional (3D) models of growing subjects. Methods Cone-beam computed tomography scans were taken before and after Class III malocclusion orthopedic treatment with miniplates. Three observers independently constructed 18 3D virtual surface models from cone-beam computed tomography scans of 3 patients. Separate 3D models were constructed for soft-tissue, cranial base, maxillary, and mandibular surfaces. The anterior cranial fossa was used to register the 3D models of before and after treatment (about 1 year of follow-up). Results Three-dimensional overlays of superimposed models and 3D color-coded displacement maps allowed visual and quantitative assessment of growth and treatment changes. The range of interobserver errors for each anatomic region was 0.4 mm for the zygomatic process of maxilla, chin, condyles, posterior border of the rami, and lower border of the mandible, and 0.5 mm for the anterior maxilla soft-tissue upper lip. Conclusions Our results suggest that this method is a valid and reproducible assessment of treatment outcomes for growing subjects. This technique can be used to identify maxillary and mandibular positional changes and bone remodeling relative to the anterior cranial fossa. PMID:19577154

  6. A novel image-domain-based cone-beam computed tomography enhancement algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Li Tianfang; Yang Yong; Heron, Dwight E; Huq, M Saiful, E-mail: lix@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232 (United States)

    2011-05-07

    Kilo-voltage (kV) cone-beam computed tomography (CBCT) plays an important role in image-guided radiotherapy. However, due to a large cone-beam angle, scatter effects significantly degrade the CBCT image quality and limit its clinical application. The goal of this study is to develop an image enhancement algorithm to reduce the low-frequency CBCT image artifacts, which are also called the bias field. The proposed algorithm is based on the hypothesis that image intensities of different types of materials in CBCT images are approximately globally uniform (in other words, a piecewise property). A maximum a posteriori probability framework was developed to estimate the bias field contribution from a given CBCT image. The performance of the proposed CBCT image enhancement method was tested using phantoms and clinical CBCT images. Compared to the original CBCT images, the corrected images using the proposed method achieved a more uniform intensity distribution within each tissue type and significantly reduced cupping and shading artifacts. In a head and a pelvic case, the proposed method reduced the Hounsfield unit (HU) errors within the region of interest from 300 HU to less than 60 HU. In a chest case, the HU errors were reduced from 460 HU to less than 110 HU. The proposed CBCT image enhancement algorithm demonstrated a promising result by the reduction of the scatter-induced low-frequency image artifacts commonly encountered in kV CBCT imaging.

  7. Investigation of saddle trajectories for cardiac CT imaging in cone-beam geometry

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Jed D [Department of Radiology, University of Utah, Salt Lake City, UT 84112 (United States); Noo, Frederic [Department of Radiology, University of Utah, Salt Lake City, UT 84112 (United States); Kudo, H [Department of Computer Science, Graduate School of Systems and Information Engineering, University of Tsukuba (Japan)

    2004-06-07

    This paper investigates cone-beam tomography for a wide class of x-ray source trajectories called saddles. In particular, a mathematical analysis of the number of intersections between a saddle and an arbitrary plane is given. This analysis demonstrates that axially truncated cone-beam projections acquired along a saddle can be used for exact reconstruction at any point in a large volume. The reconstruction can be achieved either using a new algorithm presented herein or using a formula recently introduced by Katsevich (2003 Int. J. Math. Math. Sci. 21 1305-21). The shape of the reconstructed volume and the properties of saddles make saddles attractive for cardiac imaging. Three examples of saddles are presented with a discussion of implementation on devices similar to modern C-arm systems and multislice CT scanners. Reconstruction with one of these saddles has been tested using computer-simulated data, with and without truncation. The imaged phantom for the truncated data is a FORBILD head phantom (representing the heart) that has been modified and embedded inside the FORBILD thorax phantom. The non-truncated data were generated by excluding the thorax. The reconstructed images demonstrate the accuracy of the mathematical results.

  8. External cervical resorption: an analysis using cone beam and microfocus computed tomography and scanning electron microscopy.

    Science.gov (United States)

    Gunst, V; Mavridou, A; Huybrechts, B; Van Gorp, G; Bergmans, L; Lambrechts, P

    2013-09-01

    To provide a three-dimensional representation of external cervical resorption (ECR) with microscopy, stereo microscopy, cone beam computed tomography (CT), microfocus CT and scanning electron microscopy (SEM). External cervical resorption is an aggressive form of root resorption, leading to a loss of dental hard tissues. This is due to clastic action, activated by a damage of the covering cementum and stimulated probably by infection. Clinically, it is a challenging situation as it is characterized by a late symptomatology. This is due to the pericanalar protection from a resorption-resistant sheet, composed of pre-dentine and surrounding dentine. The clastic activity is often associated with an attempt to repair, seen by the formation of osteoid tissue. Cone beam CT is extremely useful in the diagnoses and treatment planning of ECR. SEM analyses provide a better insight into the activity of osteoclasts. The root canal is surrounded by a layer of dentine that is resistant to resorption. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  9. Cone-beam CT angiography of the thorax. An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Katsuya; Shimada, Kazuhiro [Chiba Univ. (Japan). School of Medicine; Tadokoro, Hiroyuki (and others)

    1999-10-01

    The authors recently developed a cone-beam computed tomography (CT) scanner and this report presents their evaluation of its potential for thoracic vascular imaging. An X-ray tube and a video-fluoroscopic system were rotated around the objects and 360 projected images were collected in a 12-s scan. Each image was digitized and a 3 dimensional (D) image (256 x 256 x 256 voxel volume with a voxel dimension of 0.9 x 0.9 x 0.9 mm) was reconstructed. Two different 3D-CT angiographies were investigated in 2 pigs: right atriography and thoracic aortography. Each pig was anesthetized, mechanically ventilated and positioned within the scanner. Contrast agent was infused through the right atrium or the aortic root at a rate of 3 ml/s during the scan. The right atriography scan clearly delineated the anatomy of the pulmonary artery, heart chambers and thoracic aorta. The thoracic aortography scan also clearly delineated the aortic anatomy including the internal thoracic and intercostal arteries. In conclusion, cone-beam CT angiography is potentially useful for thoracic vascular imaging. (author)

  10. Dose optimisation for intraoperative cone-beam flat-detector CT in paediatric spinal surgery

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Asger Greval [Region of Northern Jutland, Department of X-ray Physics, Broenderslev (Denmark); Eiskjaer, Soeren; Kaspersen, Jon [Aalborg University Hospital, The Spinal Unit, Department of Orthopaedic Surgery, Aalborg (Denmark)

    2012-08-15

    During surgery for spinal deformities, accurate placement of pedicle screws may be guided by intraoperative cone-beam flat-detector CT. The purpose of this study was to identify appropriate paediatric imaging protocols aiming to reduce the radiation dose in line with the ALARA principle. Using O-arm registered (Medtronic, Inc.), three paediatric phantoms were employed to measure CTDI{sub w} doses with default and lowered exposure settings. Images from 126 scans were evaluated by two spinal surgeons and scores were compared (Kappa statistics). Effective doses were calculated. The recommended new low-dose 3-D spine protocols were then used in 15 children. The lowest acceptable exposure as judged by image quality for intraoperative use was 70 kVp/40 mAs, 70 kVp/80 mAs and 80 kVp/40 mAs for the 1-, 5- and 12-year-old-equivalent phantoms respectively (kappa = 0,70). Optimised dose settings reduced CTDI{sub w} doses 89-93%. The effective dose was 0.5 mSv (91-94,5% reduction). The optimised protocols were used clinically without problems. Radiation doses for intraoperative 3-D CT using a cone-beam flat-detector scanner could be reduced at least 89% compared to manufacturer settings and still be used to safely navigate pedicle screws. (orig.)

  11. Cone Beam Computed Tomographic Evaluation of Mandibular Asymmetry in Patients With Cleft Lip and Palate.

    Science.gov (United States)

    Paknahad, Maryam; Shahidi, Shoaleh; Bahrampour, Ehsan; Beladi, Amir Saied; Khojastepour, Leila

    2016-07-21

      The purpose of the present study was to compare mandibular vertical asymmetry in patients with unilateral and bilateral cleft lip and palate and subjects with normal occlusion.   Cone beam computed tomography scans of three groups consisting of 20 patients with unilateral cleft lip and palate, 20 patients affected by bilateral cleft lip and palate, and a control group of 20 subjects with normal occlusion were analyzed for this study. Condylar, ramal, and condylar plus ramal asymmetry indices were measured for all subjects using the method of Habets et al. Kruskal-Wallis and Mann-Whitney tests were used to determine any significant differences between the groups for all indices at the 95% level of confidence.   There were no significant differences regarding sex for all mandibular asymmetry indices in all three groups. All Asymmetry indices (condylar, ramal, and condylar plus ramal asymmetry) were significantly higher in the unilateral cleft group compared with the other two groups.   Cone beam computed tomography images showed that patients with cleft lip and palate suffered from mandibular asymmetry. Subjects with unilateral cleft lip and palate had a more asymmetric mandible compared with the bilateral cleft lip and palate and control groups. Therefore, the mandible appears to be the leading factor in facial asymmetry in subjects with unilateral cleft lip and palate.

  12. [The potential of cone beam computed tomography of the temporal bones in the patients presenting with otosclerosis].

    Science.gov (United States)

    Karpishchenko, S A; Zubareva, A A; Filimonov, V N; Shavgulidze, M A; Azovtseva, E A

    The objective of the present study was to analyze the potential of cone beam computed tomography of the temporal bones in the patients presenting with otosclerosis for the detection of surgically significant specific structural features of the labyrinth wall of the tympanic cavity. More than 400 tomograms of the temporal bones were obtained with the use of a cone beam tomographwere available for the investigation during the period from 2012 till 2016. The study was carried out in several steps, viz. the search for the optimal (for the given instrument) position of the patient, the experimental stage, the retrospective analysis of the tomograms and the comparison of the temporal bones of different types (pneumatic, mixed, and sclerotic) in individual patients, the comparison of the results of cone beam computed tomography (CBCT) with the intraoperative observations, and the modification of the algorithm for the analysis of temporal bone cone beam tomograms. The study included a total of 16 patients (15 women at the age from 32 to 56 years and one managed 58 years) presenting with the clinical diagnosis of otosclerosis. The results of the study were used to elaborate the algorithm for the analysis of cone beam tomograms of the temporal bones to be performed inthe stage by stage manner including the qualitative analysis of tomograms, evaluation of their quantitative parameters and additional characteristics to be taken into consideration when planning the surgical interventions on the labyrinth wall and the tympanic cavity as a preparation for the stapedoplastic treatment. The results of CBCT obtained in the present study were compared with the surgical observations. The diagnostic sensitivity and specificity of the method were estimated to be 100% and 83% respectively. It is concluded that cone beam computed tomography can be employed as a component of the diagnostic algorithm prior to the planning of surgical interventions onthe medial wall of the tympanic cavity

  13. Value of cone-beam computed tomography in the process of diagnosis and management of disorders of the temporomandibular joint.

    Science.gov (United States)

    de Boer, E W J; Dijkstra, P U; Stegenga, B; de Bont, L G M; Spijkervet, F K L

    2014-03-01

    The objective of this study was to assess the value of cone-beam computed tomographic (CT) images in the primary diagnosis and management of 128 outpatients with disorders of the temporomandibular joint (TMJ). Before a diagnosis was made and treatment planned, the history was taken, physical examination made, and the orthopantomogram studied. After assessment of the cone-beam CT, the oral and maxillofacial surgeon (specialist or resident) was allowed to revise the provisional primary diagnosis and management. The degree of certainty was rated by the clinician before and after the cone-beam CT had been assessed. The primary diagnosis was changed in 32 patients (25%), additional diagnostic procedures were changed in 57 (45%), and the treatment was changed in 15 (12%) (in 4 the treatment was changed to a (minimally) invasive procedure). A total of 74 patients (58%) had their diagnosis and management changed after the cone-beam CT had been assessed. Changes in diagnosis and management were clinically relevant in 9/32 and 9/61 patients, respectively. The clinician's certainty about the primary diagnosis increased after the cone-beam CT had been assessed in 57 patients. Logistic regression analysis showed that the odds in favour of changes in primary diagnosis and management increased when limited mandibular function was a primary symptom, the patient was taking medication for pain, and the articular eminence could not be assessed on OPT. Assessment of cone-beam CT led to changes in primary diagnosis and management in more than half the patients with disorders of the TMJ.

  14. Breathing Motion Analysis Based on Cone Beam CT Images%基于Cone Beam CT图像的呼吸运动分析

    Institute of Scientific and Technical Information of China (English)

    白相志; 周付根

    2008-01-01

    呼吸运动是有一定规律性的运动,传统呼吸运动模型用公式描述,不能准确反映不同病人的特点或同一病人不同时期的特点,无法满足实时准确分析的需要.为此,我们提出了一种通过跟踪病人自由呼吸状态下所采集的Cone Beam CT图像序列中的横隔膜的运动来建立病人呼吸运动模型的方法.该方法建立的模型与传统的呼吸运动理论模型非常相似,证明了它是可行且有效的,同时该方法更能实时准确地反映病人的呼吸运动规律,具有很高的临床实用价值.

  15. Dose cone-beam CT alter treatment plans? Comparison of preoperative implant planning using panoramic versus cone-beam CT images

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, Maria Eugenia; Jacobs, Reinhilde [Dept. of Oral and Maxillofacial Surgery, University Hospitals, Leuven (Belgium); Norge, Jorge; Castro, Carmen [Master of Periodontology, Universidad San Martin de Porres, Lima (Peru)

    2014-06-15

    The present study was performed to compare the planning of implant placement based on panoramic radiography (PAN) and cone-beam computed tomography (CBCT) images, and to study the impact of the image dataset on the treatment planning. One hundred five partially edentulous patients (77 males, 28 females, mean age: 46 years, range: 26-67 years) seeking oral implant rehabilitation were referred for presurgical imaging. Imaging consisted of PAN and CBCT imaging. Four observers planned implant treatment based on the two-dimensional (2D) image datasets and at least one month later on the three-dimensional (3D) image dataset. Apart from presurgical diagnostic and dimensional measurement tasks, the observers needed to indicate the surgical confidence levels and assess the image quality in relation to the presurgical needs. All observers confirmed that both imaging modalities (PAN and CBCT) gave similar values when planning implant diameter. Also, the results showed no differences between both imaging modalities for the length of implants with an anterior location. However, significant differences were found in the length of implants with a posterior location. For implant dimensions, longer lengths of the implants were planned with PAN, as confirmed by two observers. CBCT provided images with improved scores for subjective image quality and surgical confidence levels. Within the limitations of this study, there was a trend toward PAN-based preoperative planning of implant placement leading towards the use of longer implants within the posterior jaw bone.

  16. Development of an optimization concept for arc-modulated cone beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Silke; Nill, Simeon; Oelfke, Uwe [Department of Medical Physics in Radiation Therapy, Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

    2007-07-21

    In this paper, we propose an optimization concept for a rotation therapy technique which is referred to as arc-modulated cone beam therapy (AMCBT). The aim is a reduction of the treatment time while achieving a treatment plan quality equal to or better than that of IMRT. Therefore, the complete dose is delivered in one single gantry rotation and the beam is modulated by a multileaf collimator. The degrees of freedom are the field shapes and weights for a predefined number of beam directions. In the new optimization loop, the beam weights are determined by a gradient algorithm and the field shapes by a tabu search algorithm. We present treatment plans for AMCBT for two clinical cases. In comparison to step-and-shoot IMRT treatment plans, it was possible by AMCBT to achieve dose distributions with a better dose conformity to the target and a lower mean dose for the most relevant organ at risk. Furthermore, the number of applied monitor units was reduced for AMCBT in comparison to IMRT treatment plans.

  17. Small field dose delivery evaluations using cone beam optical computed tomography-based polymer gel dosimetry

    Directory of Open Access Journals (Sweden)

    Timothy Olding

    2011-01-01

    Full Text Available This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparison to dose readout by magnetic resonance imaging (MRI. For example, only 60% of the voxels from an optical CT dose readout of a 1 l dosimeter passed a two-dimensional Low′s gamma test (at a 3%, 3 mm criteria, relative to a treatment plan for a well-characterized pencil beam delivery. When the same dosimeter was probed by MRI, a 93% pass rate was observed. The optical dose measurement was improved after modifications to the dosimeter preparation, matching its performance with the imaging capabilities of the scanner. With the new dosimeter preparation, 99.7% of the optical CT voxels passed a Low′s gamma test at the 3%, 3 mm criteria and 92.7% at a 2%, 2 mm criteria. The fitted interjar dose responses of a small sample set of modified dosimeters prepared (a from the same gel batch and (b from different gel batches prepared on the same day were found to be in agreement to within 3.6% and 3.8%, respectively, over the full dose range. Without drawing any statistical conclusions, this experiment gives a preliminary indication that intrabatch or interbatch NIPAM dosimeters prepared on the same day should be suitable for dose sensitivity calibration.

  18. Motion compensation for cone-beam CT using Fourier consistency conditions

    Science.gov (United States)

    Berger, M.; Xia, Y.; Aichinger, W.; Mentl, K.; Unberath, M.; Aichert, A.; Riess, C.; Hornegger, J.; Fahrig, R.; Maier, A.

    2017-09-01

    In cone-beam CT, involuntary patient motion and inaccurate or irreproducible scanner motion substantially degrades image quality. To avoid artifacts this motion needs to be estimated and compensated during image reconstruction. In previous work we showed that Fourier consistency conditions (FCC) can be used in fan-beam CT to estimate motion in the sinogram domain. This work extends the FCC to 3\\text{D} cone-beam CT. We derive an efficient cost function to compensate for 3\\text{D} motion using 2\\text{D} detector translations. The extended FCC method have been tested with five translational motion patterns, using a challenging numerical phantom. We evaluated the root-mean-square-error and the structural-similarity-index between motion corrected and motion-free reconstructions. Additionally, we computed the mean-absolute-difference (MAD) between the estimated and the ground-truth motion. The practical applicability of the method is demonstrated by application to respiratory motion estimation in rotational angiography, but also to motion correction for weight-bearing imaging of knees. Where the latter makes use of a specifically modified FCC version which is robust to axial truncation. The results show a great reduction of motion artifacts. Accurate estimation results were achieved with a maximum MAD value of 708 μm and 1184 μm for motion along the vertical and horizontal detector direction, respectively. The image quality of reconstructions obtained with the proposed method is close to that of motion corrected reconstructions based on the ground-truth motion. Simulations using noise-free and noisy data demonstrate that FCC are robust to noise. Even high-frequency motion was accurately estimated leading to a considerable reduction of streaking artifacts. The method is purely image-based and therefore independent of any auxiliary data.

  19. Accuracy of implant placement based on pre-surgical planning of three-dimensional cone-beam images: a pilot study.

    NARCIS (Netherlands)

    Assche, N. Van; Steenberghe, D van; Guerrero, M.E.; Hirsch, E.; Schutyser, F.A.C.; Quirynen, M.; Jacobs, R.

    2007-01-01

    AIM: To evaluate the precision of transfer of a computer-based three-dimensional (3D) planning, using re-formatted cone-beam images, for oral implant placement in partially edentulous jaws. MATERIAL AND METHODS: Four formalin-fixed cadaver jaws were imaged in a 3D Accuitomo FPD cone-beam computed to

  20. Performance evaluation of the backprojection filtered (BPF) algorithm in circular fan-beam and cone-beam CT

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this article we introduce an exact backprojecfion filtered (BPF) type reconstruction algorithm for cone-beam scans based on Zou and Pan's work. The algorithm can reconstruct images using only the projection data passing through the parallel PI-line segments in reduced scans. Computer simulations and practical experiments are carried out to evaluate this algorithm. The BPF algorithm has a higher computational efficiency than the famous FDK algorithm. The BPF algorithm is evaluated using the practical CT projection data on a 450 keV X-ray CT system with a flat-panel detector (FPD). From the practical experiments, we get the spatial resolution of this CT system. The algorithm could achieve the spatial resolution of 2.4 lp/mm and satisfies the practical applications in industrial CT inspection.

  1. Development of Kilovoltage X-ray Dosimetry Methods and Their Application to Cone Beam Computed Tomography

    Science.gov (United States)

    Lawless, Michael J.

    The increase in popularity of pre-treatment imaging procedures in radiation therapy, such as kilovoltage cone beam computed tomography (CBCT), has been accompanied by an increase in the dose delivered to the patient from these imaging procedures. The measurement of dose from CBCT scans is complicated, as currently available kilovoltage dosimetry protocols are based on air-kerma standards and radiation detectors exhibit large energy responses at the low photon energies used in the imaging procedures. This work aims to provide the tools and methodology needed to measure the dose from these scans more accurately and precisely. Through the use of a validated Monte Carlo (MC) model of the moderately filtered (M-series) x-ray beams at the University of Wisconsin Accredited Dosimetry Calibration Laboratory, dose-to-water rates were obtained in a water phantom for the M-series x-ray beams with tube potentials from 40-250 kVp. The resulting dose-to-water rates were consistent with previously established methods, but had significantly reduced uncertainties. While detectors are commonly used to measure dose in phantom, previous investigations of the energy response of common detectors in the kilovoltage energy range have been limited to in-air geometries. The newly determined dose-to-water rates were used to characterize the in-phantom energy and depth response of thermoluminescent dosimeters and ionization chambers. When compared to previous investigations of the in-air detector response, the impact of scatter and absorption of the photon beam by the water medium was found to have a significant impact on the response of certain detectors. The dose to water in the NIST-traceable M-series x-ray beams was transferred to clinical CBCT beams and the resulting doses agreed with other dose-to-water measurement techniques. The dose to water in the CBCT beams was used to characterize the energy and depth responses of a number of detectors. The energy response in the CBCT beams agreed

  2. Influence of lead apron shielding on absorbed doses from cone-beam computed tomography.

    Science.gov (United States)

    Rottke, Dennis; Andersson, Jonas; Ejima, Ken-Ichiro; Sawada, Kunihiko; Schulze, Dirk

    2016-09-24

    The aim of the present work was to investigate absorbed and to calculate effective doses (EDs) in cone-beam computed tomography (CBCT). The study was conducted using examination protocols with and without lead apron shielding. A full-body male RANDO(®) phantom was loaded with 110 GR200A thermoluminescence dosemeter chips at 55 different sites and set up in two different CBCT systems (CS 9500(®), ProMax(®) 3D). Two different protocols were performed: the phantom was set up (1) with and (2) without a lead apron. No statistically significant differences in organ and absorbed doses from regions outside the primary beam could be found when comparing results from exposures with and without lead apron shielding. Consequently, calculating the ED showed no significant differences between the examination protocols with and without lead apron shielding. For the ProMax(®) 3D with shielding, the ED was 149 µSv, and for the examination protocol without shielding 148 µSv (SD = 0.31 µSv). For the CS 9500(®), the ED was 88 and 86 µSv (SD = 0.95 µSv), respectively, with and without lead apron shielding. The results revealed no statistically significant differences in the absorbed doses between examination with and without lead apron shielding, especially in organs outside the primary beam.

  3. Passive breath gating equipment for cone beam CT-guided RapidArc gastric cancer treatments.

    Science.gov (United States)

    Hu, Weigang; Li, Guichao; Ye, Jinsong; Wang, Jiazhou; Peng, Jiayuan; Gong, Min; Yu, Xiaoli; Studentski, Matthew T; Xiao, Ying; Zhang, Zhen

    2015-01-01

    To report preliminary results of passive breath gating (PBG) equipment for cone-beam CT image-guided gated RapidArc gastric cancer treatments. Home-developed PBG equipment integrated with the real-time position management system (RPM) for passive patient breath hold was used in CT simulation, online partial breath hold (PBH) CBCT acquisition, and breath-hold gating (BHG) RapidArc delivery. The treatment was discontinuously delivered with beam on during BH and beam off for free breathing (FB). Pretreatment verification PBH CBCT was obtained with the PBG-RPM system. Additionally, the reproducibility of the gating accuracy was evaluated. A total of 375 fractions of breath-hold gating RapidArc treatments were successfully delivered and 233 PBH CBCTs were available for analysis. The PBH CBCT images were acquired with 2-3 breath holds and 1-2 FB breaks. The imaging time was the same for PBH CBCT and conventional FB CBCT (60s). Compared to FB CBCT, the motion artifacts seen in PBH CBCT images were remarkably reduced. The average BHG RapidArc delivery time was 103 s for one 270-degree arc and 269 s for two full arcs. The PBG-RPM based PBH CBCT verification and BHG RapidArc delivery was successfully implemented clinically. The BHG RapidArc treatment was accomplished using a conventional RapidArc machine with high delivery efficiency. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    DEFF Research Database (Denmark)

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto

    2016-01-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five ...

  5. Influence of object location in different FOVs on trabecular bone microstructure measurements of human mandible: a cone beam CT study

    NARCIS (Netherlands)

    Ibrahim, N.; Parsa, A.; Hassan, B.; van der Stelt, P.; Aartman, I.H.A.; Nambiar, P.

    2014-01-01

    The aim of this study was to assess the influence of different object locations in different fields of view (FOVs) of two cone beam CT (CBCT) systems on trabecular bone microstructure measurements of a human mandible. A block of dry human mandible was scanned at five different locations (centre,

  6. Comparison of in vivo cone-beam and multidetector computed tomographic scans by three-dimensional merging software.

    Science.gov (United States)

    Rostetter, Claudio; Metzler, Philipp; Schenkel, Jan S; Seifert, Burkhardt; Luebbers, Heinz-Theo

    2015-12-01

    In dentomaxillofacial radiology, cone-beam computed tomography (CT) is used to give fast and high-resolution 3-dimensional images of bone with a low dose of radiation. However, its use for quantitative measurement of bone density based on absolute values (Hounsfield units, HU) as in multidetector CT is still controversial. We know of no in vivo study of 3-dimensional merging software that will reliably match identical bone areas of cone-beam and multidetector CT datasets. We studied 19 multidetector, and 19 cone-beam, CT scans of the skull. The two datasets were fused, corresponding points were identified for measurement, and we compared mean density. We used linear regression to analyse the relation between the two different scanning methods, and studied a total of 4180 measurements. The mean time interval between scans was 5.2 (4.7) months. Mean R(2) over all measurements was 0.63 (range 0.22 - 0.79) with a mean internal consistency (Cronbach's α) of 0.86 (range 0.61 - 0.93). The strongest linearity, seen at the left mastoid, was R(2)=0.79 with high internal consistency (Cronbach's α 0.89), and the weakest was at the left zygomatic bone with R(2)=0.22 and Cronbach's α=0.61. Measurements of bone density based on cone-beam and multidetector CT scans generated in vivo showed high and reproducible internal consistency but poor linearity.

  7. Cone beam computed tomography guided treatment delivery and planning verification for magnetic resonance imaging only radiotherapy of the brain

    DEFF Research Database (Denmark)

    Edmund, Jens M.; Andreasen, Daniel; Mahmood, Faisal;

    2015-01-01

    Background. Radiotherapy based on MRI only (MRI-only RT) shows a promising potential for the brain. Much research focuses on creating a pseudo computed tomography (pCT) from MRI for treatment planning while little attention is often paid to the treatment delivery. Here, we investigate if cone beam...

  8. Optimizing cone beam CT scatter estimation in egs_cbct for a clinical and virtual chest phantom

    DEFF Research Database (Denmark)

    Slot Thing, Rune; Mainegra-Hing, Ernesto

    2014-01-01

    PURPOSE: Cone beam computed tomography (CBCT) image quality suffers from contamination from scattered photons in the projection images. Monte Carlo simulations are a powerful tool to investigate the properties of scattered photons.egs_cbct, a recent EGSnrc user code, provides the ability...

  9. Radiation dose response of normal lung assessed by Cone Beam CT - a potential tool for biologically adaptive radiation therapy

    DEFF Research Database (Denmark)

    Bertelsen, Anders; Schytte, Tine; Bentzen, Søren M;

    2011-01-01

    Density changes of healthy lung tissue during radiotherapy as observed by Cone Beam CT (CBCT) might be an early indicator of patient specific lung toxicity. This study investigates the time course of CBCT density changes and tests for a possible correlation with locally delivered dose....

  10. Value of cone-beam computed tomography in the process of diagnosis and management of disorders of the temporomandibular joint

    NARCIS (Netherlands)

    de Boer, E. W. J.; Dijkstra, P. U.; Stegenga, B.; de Bont, L. G. M.; Spijkervet, F. K. L.

    2014-01-01

    The objective of this study was to assess the value of cone-beam computed tomographic (CT) images in the primary diagnosis and management of 128 outpatients with disorders of the temporomandibular joint (TMJ). Before a diagnosis was made and treatment planned, the history was taken, physical examina

  11. Assessment of bone segmentation quality of cone-beam CT versus multislice spiral CT: a pilot study.

    NARCIS (Netherlands)

    Loubele, M.; Maes, F.; Schutyser, F.A.C.; Marchal, G.; Jacobs, R.; Suetens, P.

    2006-01-01

    OBJECTIVES: The objective of this study was to quantitatively assess the quality of jawbone models generated from cone beam computed tomography (CBCT) by comparison with similar models obtained from multislice spiral computed tomography (MSCT). MATERIAL AND METHODS: Three case studies were performed

  12. Outcome of root canal treatment in dogs determined by periapical radiography and cone-beam computed tomography scans

    NARCIS (Netherlands)

    de Paula-Silva, F.W.G.; Hassan, B.; da Silva, L.A.B.; Leonardo, M.R.; Wu, M.K.

    2009-01-01

    The purpose of this study was to compare the favorable outcome of root canal treatment determined by periapical radiographs (PRs) and cone beam computed tomography (CBCT) scans. Ninety-six roots of dogs' teeth were used to form four groups (n= 24). In group 1, root canal treatments were performed in

  13. Laser Guidance in C-Arm Cone-Beam CT-Guided Radiofrequency Ablation of Osteoid Osteoma Reduces Fluoroscopy Time

    NARCIS (Netherlands)

    Kroes, M.W.; Busser, W.M.H.; Hoogeveen, Y.L.; Lange, F. de; Schultze Kool, L.J.

    2017-01-01

    PURPOSE: To assess whether laser guidance can reduce fluoroscopy and procedure time of cone-beam computed tomography (CBCT)-guided radiofrequency (RF) ablations of osteoid osteoma compared to freehand CBCT guidance. MATERIALS AND METHODS: 32 RF ablations were retrospectively analyzed, 17

  14. Designing a novel dental root analogue implant using cone beam computed tomography and CAD/CAM technology

    NARCIS (Netherlands)

    Moin, D.A.; Hassan, B.; Mercelis, P.; Wismeijer, D.

    2013-01-01

    Objectives The study aim is to introduce a novel preemptively constructed dental root analogue implant (RAI) based on three-dimensional (3D) root surface models obtained from a cone beam computed tomography (CBCT) scan, computer aided designing and computer aided manufacturing technology. Materials

  15. A cone-beam CT based technique to augment the 3D virtual skull model with a detailed dental surface.

    NARCIS (Netherlands)

    Swennen, G.R.; Mommaerts, M.Y.; Abeloos, J.V.S.; Clercq, C. De; Lamoral, P.; Neyt, N.; Casselman, J.W.; Schutyser, F.A.C.

    2009-01-01

    Cone-beam computed tomography (CBCT) is used for maxillofacial imaging. 3D virtual planning of orthognathic and facial orthomorphic surgery requires detailed visualisation of the interocclusal relationship. This study aimed to introduce and evaluate the use of a double CBCT scan procedure with a mod

  16. Accuracy of trabecular bone microstructural measurement at planned dental implant sites using cone-beam CT datasets

    NARCIS (Netherlands)

    Ibrahim, N.; Parsa, A.; Hassan, B.; van der Stelt, P.; Aartman, I.H.A.; Wismeijer, D.

    2014-01-01

    Objective Cone-beam CT (CBCT) images are infrequently utilized for trabecular bone microstructural measurement due to the system's limited resolution. The aim of this study was to determine the accuracy of CBCT for measuring trabecular bone microstructure in comparison with micro CT (μCT). Materials

  17. The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study

    OpenAIRE

    Huang, Yan; Dessel, Jeroen Van; Nicolielo, Laura; Van de Casteele, Elke; Slagmolen, Pieter; Jacobs, Reinhilde

    2015-01-01

    Huang Y., Van Dessel J., Nicolielo L., Van de Casteele E., Slagmolen P., Jacobs R., ''The reliability of cone-beam computed tomography to analyze trabecular and cortical bone structures: an in-vitro study'', 24th annual congress of the European Association for Osseointegration - EAO 2015, September 24-26, 2015, Stockholm, Sweden.

  18. Clinical relevance of cone beam computed tomography in mandibular third molar removal: A multicentre, randomised, controlled trial

    NARCIS (Netherlands)

    Ghaeminia, H.; Gerlach, N.L.; Hoppenreijs, T.J.; Kicken, M.; Dings, J.P.; Borstlap, W.A.; Haan, T. de; Berge, S.J.; Meijer, G.J.; Maal, T.J.J.

    2015-01-01

    PURPOSE: The aims of this study were to investigate the effectiveness of cone beam computed tomography (CBCT) compared to panoramic radiography (PR), prior to mandibular third molar removal, in reducing patient morbidity, and to identify risk factors associated with inferior alveolar nerve (IAN) inj

  19. Accuracy of linear measurements from cone-beam computed tomography-derived surface models of different voxel sizes

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Huddleston Slater, James J R; Ren, Yijin

    2010-01-01

    INTRODUCTION: The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the li

  20. Segmentation process significantly influences the accuracy of 3D surface models derived from cone beam computed tomography

    NARCIS (Netherlands)

    Fourie, Zacharias; Damstra, Janalt; Schepers, Rutger H; Gerrits, Pieter; Ren, Yijin

    2012-01-01

    AIMS: To assess the accuracy of surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols. MATERIALS AND METHODS: Seven fresh-frozen cadaver heads were used. There was no conflict of interests in this study. CBCT scans were made of the heads and 3D

  1. Impacted maxillary canines and root resorptions of neighbouring teeth: a radiographic analysis using cone-beam computed tomography

    NARCIS (Netherlands)

    Lai, C.S.; Bornstein, M.M.; Mock, L.; Heuberger, B.M.; Dietrich, T.; Katsaros, C.

    2013-01-01

    The study analyses the location of impacted maxillary canines and factors influencing root resorptions of adjacent teeth using cone-beam computed tomography (CBCT). In addition, the interrater reliability between observers of two different dental specialties for radiographic parameters will be evalu

  2. The influence of the segmentation process on 3D measurements from cone beam computed tomography-derived surface models

    NARCIS (Netherlands)

    Engelbrecht, Willem P.; Fourie, Zacharias; Damstra, Janalt; Gerrits, Peter O.; Ren, Yijin

    2013-01-01

    To compare the accuracy of linear and angular measurements between cephalometric and anatomic landmarks on surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols was the aim of this study. CBCT scans were made of cadaver heads and 3D surface mod

  3. Influence of object location in different FOVs on trabecular bone microstructure measurements of human mandible: a cone beam CT study

    NARCIS (Netherlands)

    Ibrahim, N.; Parsa, A.; Hassan, B.; van der Stelt, P.; Aartman, I.H.A.; Nambiar, P.

    2014-01-01

    The aim of this study was to assess the influence of different object locations in different fields of view (FOVs) of two cone beam CT (CBCT) systems on trabecular bone microstructure measurements of a human mandible. A block of dry human mandible was scanned at five different locations (centre, lef

  4. The accuracy of the imaging reformation of cone beam computed tomography for the assessment of bone defect healing

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ho Duk; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Kyung Hee Univ., Seoul (Korea, Republic of)

    2007-06-15

    To evaluate the accuracy of the imaging reformation of cone beam computed tomography for the assessment of bone defect healing in rat model. Sprague-Dawely strain rats weighing about 350 gms were selected. Then critical size bone defects were done at parietal bone with implantation of collagen sponge. The rats were divided into seven groups of 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, and 8 weeks. The healing of surgical defect was assessed by multiplanar reconstruction (MPR) images and three-dimensional (3-D) images of cone beam computed tomography, compared with soft X-ray radiograph and histopathologic examination. MPR images and 3-D images showed similar reformation of the healing amount at 3 days, 1 week, 2 weeks, and 8 weeks, however, lower reformation at 3 weeks, 4 weeks, and 6 weeks. According to imaging-based methodologies, MPR images revealed similar reformation of the healing mount than 3-D images compare with soft X-ray image. Among the four threshold values for 3-D images, 400-500 HU revealed similar reformation of the healing amount. Histopathologic examination confirmed the newly formed trabeculation correspond with imaging-based mythologies. MPR images revealed higher accuracy of the imaging reformation of cone beam computed tomography and cone beam computed tomography is a clinically useful diagnostic tool for the assessment of bone defect healing.

  5. Accuracy of linear measurements from cone-beam computed tomography-derived surface models of different voxel sizes

    NARCIS (Netherlands)

    Damstra, Janalt; Fourie, Zacharias; Huddleston Slater, James J R; Ren, Yijin

    2010-01-01

    INTRODUCTION: The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the li

  6. Radiologic evaluation of an unusually sized complex odontoma involving the maxillary sinus by cone beam computed tomography.

    Science.gov (United States)

    Isler, Sabri Cemil; Demircan, Sabit; Soluk, Merva; Cebi, Zerrin

    2009-01-01

    As a group, odontomas are the most common odontogenic neoplasms. This case report illustrates the benefits of cone beam computed tomography, in terms of treatment planning and surgical technique, to localize a large maxillary odontoma and accurately establish its relationship with the maxillary sinus and molar.

  7. A dual centre study of setup accuracy for thoracic patients based on Cone-Beam CT data

    DEFF Research Database (Denmark)

    Nielsen, Tine B; Hansen, Vibeke N; Westberg, Jonas;

    2011-01-01

    BACKGROUND AND PURPOSE: To compare setup uncertainties at two different institutions by using identical imaging and analysis techniques for thoracic patients with different fixation equipments. METHODS AND MATERIALS: Patient registration results from Cone-Beam CT (CBCT) scans of 174 patients were...

  8. Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

    NARCIS (Netherlands)

    Vos, W. De; Casselman, J.W.; Swennen, G.R.

    2009-01-01

    This study reviewed the literature on cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial (OMF) region. A PUBMED search (National Library of Medicine, NCBI; revised 1 December 2007) from 1998 to December 2007 was conducted. This search revealed 375 papers, which were scree

  9. Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature.

    NARCIS (Netherlands)

    Guijarro-Martinez, R.; Swennen, G.R.J.

    2011-01-01

    A systematic review of the literature concerning upper airway imaging and analysis using cone-beam computed tomography (CBCT) was performed. A PubMed search (National Library of Medicine, NCBI; revised 9th January 2011) yielded 382 papers published between 1968 and 2010. The 382 full papers were scr

  10. High-dose-rate prostate brachytherapy based on registered transrectal ultrasound and in-room cone-beam CT images

    NARCIS (Netherlands)

    Even, Aniek J.G.; Nuver, Tonnis T.; Westendorp, Hendrik; Hoekstra, Carel J.; Slump, C.H.; Minken, Andre W.

    2014-01-01

    Purpose To present a high-dose-rate (HDR) brachytherapy procedure for prostate cancer using transrectal ultrasound (TRUS) to contour the regions of interest and registered in-room cone-beam CT (CBCT) images for needle reconstruction. To characterize the registration uncertainties between the two ima

  11. Unilateral Fusion of Maxillary Lateral Incisor: Diagnosis Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Iury Oliveira Castro

    2014-01-01

    Full Text Available Objective. The objective of this paper is to report a dental fusion case focusing on clinical and radiographic features for the diagnosis. Method. To report a case of right maxillary lateral incisor fusion and a supernumerary tooth, the anatomy of the root canal and dental united portion were assessed by cone beam computed tomography (CBCT. Results. The clinical examination showed dental juxtaposition with the absence of interdental papilla and esthetic impairment in the right maxillary lateral incisor region. The periapical radiography did not provide enough information for the differential diagnosis due to the inherent limitations of this technique. CBCT confirmed the presence of tooth fusion. Conclusion. CBCT examination supports the diagnosis and provides both the identification of changes in tooth development and the visualization of their extent and limits.

  12. Maxillary first molar with seven root canals diagnosed with cone-beam computed tomography scanning

    Directory of Open Access Journals (Sweden)

    Anil Munavalli

    2015-01-01

    Full Text Available Nonsurgical endodontic therapy of a right maxillary first molar with three roots and seven root canals. This unusual morphology was diagnosed using a dental operating microscope (DOM and confirmed with the help of cone-beam computed tomography (CBCT images. CBCT axial images showed that both the palatal and distobuccal root have a Vertucci type II canal pattern, whereas the mesiobuccal root showed a Sert and Bayirli type XVIII canal configuration. The use of a DOM and CBCT imaging in endodontically challenging cases can facilitate a better understanding of the complex root canal anatomy, which ultimately enables the clinician to explore the root canal system and clean, shape, and obturate it more efficiently.

  13. Limited-angle reverse helical cone-beam CT for pipeline with low rank decomposition

    Science.gov (United States)

    Wu, Dong; Zeng, Li

    2014-10-01

    In this paper, tomographic imaging of pipeline in service by cone-beam computed tomography (CBCT) is studied. With the developed scanning strategy and image model, the quality of reconstructed image is improved. First, a limited-angle reverse helical scanning strategy based on C-arm computed tomography (C-arm CT) is developed for the projection data acquisition of pipeline in service. Then, an image model which considering the resemblance among slices of pipeline is developed. Finally, split Bregman method based algorithm is implemented in solving the model aforementioned. Preliminary results of simulation experiments show that the projection data acquisition strategy and reconstruction method are efficient and feasible, and our method is superior to Feldkamp-Davis-Kress (FDK) algorithm and simultaneous algebraic reconstruction technique (SART).

  14. Anatomical Variation of the Maxillary Sinus in Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Marcelo Lupion Poleti

    2014-01-01

    Full Text Available Purpose. The aim of this paper is to report a case in which the cone beam computed tomography (CBCT was important for the confirmation of the presence of maxillary sinus septum and, therefore, the absence of a suspected pathologic process. Case Description. A 27-year-old male patient was referred for the assessment of a panoramic radiograph displaying a radiolucent area with radiopaque border located in the apical region of the left upper premolars. The provisional diagnosis was either anatomical variation of the maxillary sinuses or a bony lesion. Conclusion. The CBCT was important for an accurate assessment and further confirmation of the presence of maxillary septum, avoiding unnecessary surgical explorations.

  15. Geometric Parameters Estimation and Calibration in Cone-Beam Micro-CT

    Directory of Open Access Journals (Sweden)

    Jintao Zhao

    2015-09-01

    Full Text Available The quality of Computed Tomography (CT images crucially depends on the precise knowledge of the scanner geometry. Therefore, it is necessary to estimate and calibrate the misalignments before image acquisition. In this paper, a Two-Piece-Ball (TPB phantom is used to estimate a set of parameters that describe the geometry of a cone-beam CT system. Only multiple projections of the TPB phantom at one position are required, which can avoid the rotation errors when acquiring multi-angle projections. Also, a corresponding algorithm is derived. The performance of the method is evaluated through simulation and experimental data. The results demonstrated that the proposed method is valid and easy to implement. Furthermore, the experimental results from the Micro-CT system demonstrate the ability to reduce artifacts and improve image quality through geometric parameter calibration.

  16. Scattering correction based on regularization de-convolution for Cone-Beam CT

    CERN Document Server

    Xie, Shi-peng

    2016-01-01

    In Cone-Beam CT (CBCT) imaging systems, the scattering phenomenon has a significant impact on the reconstructed image and is a long-lasting research topic on CBCT. In this paper, we propose a simple, novel and fast approach for mitigating scatter artifacts and increasing the image contrast in CBCT, belonging to the category of convolution-based method in which the projected data is de-convolved with a convolution kernel. A key step in this method is how to determine the convolution kernel. Compared with existing methods, the estimation of convolution kernel is based on bi-l1-l2-norm regularization imposed on both the intermediate the known scatter contaminated projection images and the convolution kernel. Our approach can reduce the scatter artifacts from 12.930 to 2.133.

  17. Cone Beam Computed Tomography Findings in Calcifying Cystic Odontogenic Tumor Associated with Odontome: A Case Report

    Directory of Open Access Journals (Sweden)

    Tushar Phulambrikar

    2015-12-01

    Full Text Available The calcifying cystic odontogenic tumor (CCOT is a rare cystic odontogenic neoplasm frequently found in association with odontome. This report documents a case of CCOT associated with an odontome arising in the anterior maxilla in a 28-year-old man. Conventional radiographs showed internal calcification within the lesion but were unable to visualize its relation with the adjacent structures and its accurate extent. In this case cone beam computed tomography (CBCT could accurately reveal the extent and the internal structure of the lesion which aided the presumptive diagnosis of the lesion as CCOT. This advanced imaging technique proved to be extremely useful in the radiographic assessment and management of this neoplasm of the maxilla.

  18. Evaluation of canalis basilaris medianus using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Syed, Ali Z.; Zahedpasha, Samir [Dept. of Oral and Maxillofacial Medicine and Diagnostic Sciences, CWRU School of Dental Medicine, Cleveland (United States); Rathore, Sonali A. [Dept. of Oral Diagnostic Sciences, VCU School of Dentistry, Richmond (United States); Mupparapu, Mel [Dept. of Radiology, University of Pennsylvania School of Dental Medicine, Philadelphia (United States)

    2016-06-15

    The aim of this report is to present two cases of canalis basilaris medianus as identified on cone-beam computed tomography (CBCT) in the base of the skull. The CBCT data sets were sent for radiographic consultation. In both cases, multi-planar views revealed an osseous defect in the base of the skull in the clivus region, the sagittal view showed a unilateral, well-defined, non-corticated, track-like low-attenuation osseous defect in the clivus. The appearance of the defect was highly reminiscent of a fracture of the clivus. The borders of osseous defect were smooth, and no other radiographic signs suggestive of osteolytic destructive processes were noted. Based on the overall radiographic examination, a radiographic impression of canalis basilaris medianus was made. Canalis basilaris medianus is a rare anatomical variant and is generally observed on the clivus. Due to its potential association with meningitis, it should be recognized and reported to avoid potential complications.

  19. Artefacts in Cone Beam CT Mimicking an Extrapalatal Canal of Root-Filled Maxillary Molar.

    Science.gov (United States)

    Camilo, Carla Cristina; Brito-Júnior, Manoel; Faria-E-Silva, André Luis; Quintino, Alex Carvalho; de Paula, Adrianne Freire; Cruz-Filho, Antônio Miranda; Sousa-Neto, Manoel Damião

    2013-01-01

    Despite the advantages of cone-beam computed tomography (CBCT), the images provided by this diagnostic tool can produce artifacts and compromise accurate diagnostic assessment. This paper describes an endodontic treatment of a maxillary molar where CBCT images suggested the presence of a nonexistent third root canal in the palatal root. An endodontic treatment was performed in a first maxillary molar with palatal canals, and the tooth was restored with a cast metal crown. The patient returned four years later presenting with a discomfort in chewing, which was reduced after occlusal adjustment. CBCT was prescribed to verify additional diagnostic information. Axial scans on coronal, middle, and apical palatal root sections showed images similar to a third root canal. However, sagittal scans demonstrated that these images were artifacts caused by root canal fillings. A careful interpretation of CBCT images in root-filled teeth must be done to avoid mistakes in treatment.

  20. Patient radiation dose and protection from cone-beam computed tomography.

    Science.gov (United States)

    Li, Gang

    2013-06-01

    After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from 19 µSv to 1073 µSv and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply understand the potential risk from CBCT, this report also reviewed the effective doses from literatures on intra-oral radiograph, panoramic radiograph, lateral and posteroanterior cephalometric radiograph, multi-slice CT, and so on. The protection effect of thyroid collar and leaded glasses were also reviewed.

  1. Patient radiation dose and protection from cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gang [Peking University School and Hospital of Stomatology, Beijing (China)

    2013-06-15

    After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from 19 {mu}Sv to 1073 {mu}Sv and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply understand the potential risk from CBCT, this report also reviewed the effective doses from literatures on intra-oral radiograph, panoramic radiograph, lateral and posteroanterior cephalometric radiograph, multi-slice CT, and so on. The protection effect of thyroid collar and leaded glasses were also reviewed.

  2. Robust scatter correction method for cone-beam CT using an interlacing-slit plate

    CERN Document Server

    Huang, Kuidong; Zhang, Dinghua; Zhang, Hua; Shi, Wenlong

    2015-01-01

    Cone-beam computed tomography (CBCT) has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate (ISP) is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification. The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corre...

  3. Cone Beam CT在口腔种植外科中的应用

    Institute of Scientific and Technical Information of China (English)

    陈宁

    2011-01-01

    Cone beam CT技术已成为口腔颌面部疾病诊断和临床研究的重要方法,与常规的平片以及口腔全景片相比有着许多明显的优势。在口腔种植外科的应用中能够提供精确的、定量的、三维图像信息,这对于解剖学研究、临床评价、术前诊断和随访观察是非常重要的,可以有效地提高种植的成功率,避免并发症。

  4. [Use of Cone Beam Computed Tomography in endodontics: rational case selection criteria].

    Science.gov (United States)

    Rosen, E; Tsesis, I

    2016-01-01

    To present rational case selection criteria for the use of CBCT (Cone Beam Computed Tomography) in endodontics. This article reviews the literature concerning the benefits of CBCT in endodontics, alongside its radiation risks, and present case selection criteria for referral of endodontic patients to CBCT. Up to date, the expected ultimate benefit of CBCT to the endodontic patient is yet uncertain, and the current literature is mainly restricted to its technical efficacy. In addition, the potential radiation risks of CBCT scan are stochastic in nature and uncertain, and are worrying especially in pediatric patients. Both the efficacy of CBCT in supporting the endodontic practitioner decision making and in affecting treatment outcomes, and its long term potential radiation risks are yet uncertain. Therefore, a cautious rational decision making is essential when a CBCT scan is considered in endodontics. Risk-benefit considerations are presented.

  5. Cone Beam Computed Tomographic Evaluation and Diagnosis of Mandibular First Molar with 6 Canals

    Directory of Open Access Journals (Sweden)

    Shiraz Pasha

    2016-01-01

    Full Text Available Root canal treatment of tooth with aberrant root canal morphology is very challenging. So thorough knowledge of both the external and internal anatomy of teeth is an important aspect of root canal treatment. With the advancement in technology it is imperative to use modern diagnostic tools such as magnification devices, CBCT, microscopes, and RVG to confirm the presence of these aberrant configurations. However, in everyday endodontic practice, clinicians have to treat teeth with atypical configurations for root canal treatment to be successful. This case report presents the management of a mandibular first molar with six root canals, four in mesial and two in distal root, and also emphasizes the use and importance of Cone Beam Computed Tomography (CBCT as a diagnostic tool in endodontics.

  6. A Model-Based Scatter Artifacts Correction for Cone Beam CT

    CERN Document Server

    Zhao, Wei; Zhu, Jun; Wang, Luyao; Xing, Lei

    2016-01-01

    The purpose of this work is to provide a fast and accurate scatter artifacts correction algorithm for cone beam CT (CBCT) imaging. The method starts with an estimation of coarse scatter profiles for a set of CBCT data in either image domain or projection domain. A denoising algorithm designed specifically for Poisson signals is then applied to derive the final scatter distribution. Qualitative and quantitative evaluations using thorax and abdomen phantoms with Monte Carlo (MC) simulations, experimental Catphan phantom data, and in vivo human data acquired for a clinical image guided radiation therapy were performed. Results show that the proposed algorithm can significantly reduce scatter artifacts and recover the correct HU in either projection domain or image domain. For the MC thorax phantom study, four components segmentation yield the best results, while the results of three components segmentation are still acceptable. For the Catphan phantom data, the mean value over all pixels in the residual image is...

  7. Cone-beam computed tomography exploration and surgical management of palatal, inverted, and impacted mesiodens

    Directory of Open Access Journals (Sweden)

    Mounir Omami

    2015-01-01

    Full Text Available Supernumerary teeth are extra teeth or toothlike structures which may have either erupted or unerupted in addition to the 20 deciduous teeth and the 32 permanent teeth. Mesiodens is one of these located in the midline between the two central incisors. Their presence may give rise to a variety of clinical problems. This paper describes a rare case of palatal placed, inverted and impacted mesiodens associated to two supernumerary teeth which were detected during a radiographic examination for delayed eruption of permanent central incisors in the case of a healthy 8-year-old girl monitored at the oral surgery service while discussing the usefulness of cone beam computed tomography for accurate diagnosis and management.

  8. Calculating tumor trajectory and dose-of-the-day using cone-beam CT projections

    CERN Document Server

    Jones, Bernard L; Miften, Moyed

    2015-01-01

    Purpose: Cone-beam CT (CBCT) projection images provide anatomical data in real-time over several respiratory cycles, forming a comprehensive picture of tumor movement. We developed and validated a method which uses these projections to determine the trajectory of and dose to highly mobile tumors during each fraction of treatment. Methods: CBCT images of a respiration phantom were acquired, the trajectory of which mimicked a lung tumor with high amplitude (up to 2.5 cm) and hysteresis. A template-matching algorithm was used to identify the location of a steel BB in each CBCT projection, and a Gaussian probability density function for the absolute BB position was calculated which best fit the observed trajectory of the BB in the imager geometry. Two modifications of the trajectory reconstruction were investigated: first, using respiratory phase information to refine the trajectory estimation (Phase), and second, using the Monte Carlo (MC) method to sample the estimated Gaussian tumor position distribution. Resu...

  9. Developmental salivary gland depression in the ascending mandibular ramous: A cone-beam computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Christine A.; Ahn, Yoon Hee; Odell, Scott; Mupparapu, Mel; Graham, David Mattew [University of Pennsylvania School of Dental Medicine, Philadelphia (United States)

    2016-09-15

    A static, unilateral, and focal bone depression located lingually within the ascending ramous, identical to the Stafne's bone cavity of the angle of the mandible, is being reported. During development of the mandible, submandibular gland inclusion may lead to the formation of a lingual concavity, which could contain fatty tissue, blood vessels, or soft tissue. However, similar occurrences in the ascending ramous at the level of the parotid gland are extremely rare. Similar cases were previously reported in dry, excavated mandibles, and 3 cases were reported in living patients. A 52-year-old African American male patient was seen for pain in the mandibular teeth. Panoramic radiography showed an unusual concavity within the left ascending ramous. Cone-beam computed tomography confirmed this incidental finding. The patient was cleared for the extraction of non-restorable teeth and scheduled for annual follow-up.

  10. Cone beam CT for diagnosis and treatment planning in trauma cases.

    Science.gov (United States)

    Palomo, Leena; Palomo, J Martin

    2009-10-01

    Three-dimensional imaging offers many advantages in making diagnoses and planning treatment. This article focuses on cone beam CT (CBCT) for making diagnoses and planning treatment in trauma-related cases. CBCT equipment is smaller and less expensive than traditional medical CT equipment and is tailored to address challenges specific to the dentoalveolar environment. Like medical CT, CBCT offers a three-dimensional view that conventional two-dimensional dental radiography fails to provide. CBCT combines the strengths of medical CT with those of conventional dental radiography to accommodate unique diagnostic and treatment-planning applications that have particular utility in dentoalveolar trauma cases. CBCT is useful, for example, in identifying tooth fractures relative to surrounding alveolar bone, in determining alveolar fracture location and morphology, in analyzing ridge-defect height and width, and in imaging temporomandibular joints. Treatment-planning applications include those involving extraction of fractured teeth, placement of implants, exposure of impacted teeth, and analyses of airways.

  11. Cone-beam computed tomography in endodontics: are we there yet?

    Science.gov (United States)

    Nesari, Royeen; Rossman, Louis E; Kratchman, Samuel I

    2009-01-01

    From digital radiography units to office computer systems, there are several pieces of equipment that make up today's high-tech dental office. Recently, advances in dental imaging have allowed cone-beam computed tomography (CBCT), which is a form of 3-dimensional radiography, to gain increasing popularity as another major office component. In consideration of the current economic conditions, cost has become a definite obstacle for many practitioners. With several brands available, this technology has nonetheless generated considerable attention for use in presurgical treatment planning and diagnosis. However, is there enough evidence for its use in endodontics? This article aims to bring to light the many exciting features of CBCT, including its operation, impact, and feasibility in endodontics.

  12. Cone-Beam Computed Tomography contrast validation of an artificial periodontal phantom for use in endodontics.

    Science.gov (United States)

    Michetti, Jerome; Basarab, Adrian; Tran, Michel; Diemer, Franck; Kouame, Denis

    2015-01-01

    Validation of image processing techniques such as endodontic segmentations in cone-beam computed tomography (CBCT) is a challenging issue because of the lack of ground truth in in vivo experiments. The purpose of our study was to design an artificial surrounding tissues phantom able to provide CBCT image quality of real extracted teeth, similar to in vivo conditions. Note that these extracted teeth could be previously scanned using micro computed tomography (μCT) to access true quantitative measurements of the root canal anatomy. Different design settings are assessed in our study by comparison to in vivo images, in terms of the contrast-to-noise ratio (CNR) obtained between different anatomical structures. Concerning the root canal and the dentine, the best design setup allowed our phantom to provide a CNR difference of only 3% compared to clinical cases.

  13. Cone Beam Computed Tomography (CBCT) in the Field of Interventional Oncology of the Liver

    Energy Technology Data Exchange (ETDEWEB)

    Bapst, Blanche, E-mail: blanchebapst@hotmail.com; Lagadec, Matthieu, E-mail: matthieu.lagadec@bjn.aphp.fr [Beaujon Hospital, University Hospitals Paris Nord Val de Seine, Beaujon, Department of Radiology (France); Breguet, Romain, E-mail: romain.breguet@hcuge.ch [University Hospital of Geneva (Switzerland); Vilgrain, Valérie, E-mail: Valerie.vilgrain@bjn.aphp.fr; Ronot, Maxime, E-mail: maxime.ronot@bjn.aphp.fr [Beaujon Hospital, University Hospitals Paris Nord Val de Seine, Beaujon, Department of Radiology (France)

    2016-01-15

    Cone beam computed tomography (CBCT) is an imaging modality that provides computed tomographic images using a rotational C-arm equipped with a flat panel detector as part of the Angiography suite. The aim of this technique is to provide additional information to conventional 2D imaging to improve the performance of interventional liver oncology procedures (intraarterial treatments such as chemoembolization or selective internal radiation therapy, and percutaneous tumor ablation). CBCT provides accurate tumor detection and targeting, periprocedural guidance, and post-procedural evaluation of treatment success. This technique can be performed during intraarterial or intravenous contrast agent administration with various acquisition protocols to highlight liver tumors, liver vessels, or the liver parenchyma. The purpose of this review is to present an extensive overview of published data on CBCT in interventional oncology of the liver, for both percutaneous ablation and intraarterial procedures.

  14. Establishment of reference mandibular plane for anterior alveolar morphology evaluation using cone beam computed tomography

    Institute of Scientific and Technical Information of China (English)

    Rong-yang WANG; Min HAN; Hong LIU; Chun-ling WANG; Hong-hong XIAN; Lei ZHANG; Shi-jie ZHANG; Dong-xu LIU

    2012-01-01

    To propose a method of establishing the reference mandibular plane (MP),which could be reestablished according to the coordinates of the reference points,and then facilitate the assessment of anterior alveolar morphology using cone beam computed tomography (CBCT),sixty patients with bimaxillary protrusion were randomly selected and CBCT scans were taken.The CBCT scans were transferred to Materialism's interactive medical image control system 10.01 (MIMICS 10.01),and three dimensional models of the entire jaws were constructed.Reference points determining the reference MP were positioned in the coronal,axial,sagittal windows,and the points were exactly located by recording their coordinates in the interfaces of software.The reference MP provided high intra-observer reliability (Pearson's r 0.992 to 0.999),and inter-observer reliability (intra-class correlation coefficients (ICCs)0.996 to 0.999).

  15. Current status of dental caries diagnosis using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Seok; Ahn, Jin Soo; Kwon, Ho Beom; Lee, Seung Pyo [School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    2011-06-15

    The purpose of this article is to review the current status of dental caries diagnosis using cone beam computed tomography (CBCT). An online PubMed search was performed to identify studies on caries research using CBCT. Despite its usefulness, there were inherent limitations in the detection of caries lesions through conventional radiograph mainly due to the two-dimensional (2D) representation of caries lesions. Several efforts were made to investigate the three-dimensional (3D) image of lesion, only to gain little popularity. Recently, CBCT was introduced and has been used for diagnosis of caries in several reports. Some of them maintained the superiority of CBCT systems, however it is still under controversies. The CBCT systems are promising, however they should not be considered as a primary choice of caries diagnosis in everyday practice yet. Further studies under more standardized condition should be performed in the near future.

  16. Cone Beam Computed Tomography (CBCT Features of a Rare Fibro-Osseous Lesion: A Case Report

    Directory of Open Access Journals (Sweden)

    Mahrokh Imanimoghaddam

    2013-03-01

    Full Text Available Cone beam computed tomography is a useful technique for imaging the craniofacial lesions. It produces more realistic images that facilitate interpretation. Juvenile ossifying fibroma (JOF is a rare and benign fibro-osseous neoplasm that arises within the craniofacial bones, especially in the maxilla. Mandibular lesions can be seen in 10% of the cases.In both jaws, it has a predilection for the premolar and molar regions (it is mostly seen in premolar and molar regions. Radiographically, it can be present as a radiolucent, mixed or radiopaque lesion. Radiodensity varies from purely radiolucent masses to mixed densities with prominent radiopacity as the lesion matures.This case report highlights a JOF with large foci of odontome-like radiopacities in a 6-year-old boy's mandibular anterior region. The location of the lesion in the anterior mandible and comparatively rapid formation of large odontome-like radiopaque foci at this early agehas made it a rare entity.

  17. Diagnosis and Treatment of a Type III Dens Invagination Using Cone-Beam Computed Tomography

    Science.gov (United States)

    Bahmani, Mohsen; Adl, Alireza; Javanmardi, Samane; Naghizadeh, Sina

    2016-01-01

    A 20-year-old man presented with the history of pain and swelling in the anterior maxillary segment. The periapical radiography was indicative of a dental anomaly in right maxillary lateral incisor. Due to the insufficient information from conventional radiography, cone-beam computed tomography (CBCT) was ordered. CBCT showed apical root resorption, large apical lucency and two separate canals with distinct apical foramen (Oehlers type III dens invagination). The CBCT image was used as a guide for dentine removal with an ultrasonic tip. Conventional root canal therapy was done using lateral compaction technique. One-and two-year follow-up radiographies revealed periapical repair and absence of symptoms. PMID:27790268

  18. Multiple idiopathic external and internal resorption: Case report with cone-beam computed tomography findings

    Energy Technology Data Exchange (ETDEWEB)

    Celikten, Berkan; Uzuntas, Ceren Feriha; Kurt, Hakan [Faculty of Dentistry, Ankara University, Ankara (Turkmenistan)

    2014-12-15

    Root resorption is loss of dental hard tissue as a result of clastic activities. The dental hard tissue of permanent teeth does not normally undergo resorption, except in cases of inflammation or trauma. However, there are rare cases of tooth resorption of an unknown cause, known as 'idiopathic root resorption.' This report would discuss a rare case of multiple idiopathic resorption in the permanent maxillary and mandibular teeth of an otherwise healthy 36-year-old male patient. In addition to a clinical examination, the patient was imaged using conventional radiography and cone-beam computed tomography (CBCT). The examinations revealed multiple external and internal resorption of the teeth in all four quadrants of the jaws with an unknown cause. Multiple root resorption is a rare clinical phenomenon that should be examined using different radiographic modalities. Cross-sectional CBCT is useful in the diagnosis and examination of such lesions.

  19. Multiple idiopathic external and internal resorption: Case report with cone-beam computed tomography findings.

    Science.gov (United States)

    Celikten, Berkan; Uzuntas, Ceren Feriha; Kurt, Hakan

    2014-12-01

    Root resorption is loss of dental hard tissue as a result of clastic activities. The dental hard tissue of permanent teeth does not normally undergo resorption, except in cases of inflammation or trauma. However, there are rare cases of tooth resorption of an unknown cause, known as "idiopathic root resorption." This report would discuss a rare case of multiple idiopathic resorption in the permanent maxillary and mandibular teeth of an otherwise healthy 36-year-old male patient. In addition to a clinical examination, the patient was imaged using conventional radiography and cone-beam computed tomography (CBCT). The examinations revealed multiple external and internal resorption of the teeth in all four quadrants of the jaws with an unknown cause. Multiple root resorption is a rare clinical phenomenon that should be examined using different radiographic modalities. Cross-sectional CBCT is useful in the diagnosis and examination of such lesions.

  20. Role of C-arm cone-beam CT in chemoembolization for hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Cheol [Dept. of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul (Korea, Republic of)

    2015-02-15

    With the advent of C-arm cone-beam computed tomography (CBCT), minimally-invasive procedures in the angiography suite made a new leap beyond the limitations of 2-dimensional (D) angiography alone. C-arm CBCT can help interventional radiologists in several ways with the treatment of hepatocellular carcinoma (HCC); visualization of small tumors and tumor-feeding arteries, identification of occult lesion and 3D configuration of tortuous hepatic arteries, assurance of completeness of chemoembolization, suggestion of presence of extrahepatic collateral arteries supplying HCCs, and prevention of nontarget embolization. With more improvements in the technology, C-arm CBCT may be essential in all kinds of interventional procedures in the near future.

  1. Cone-beam computed tomography exploration and surgical management of palatal, inverted, and impacted mesiodens.

    Science.gov (United States)

    Omami, Mounir; Chokri, Abdellatif; Hentati, Hajer; Selmi, Jamil

    2015-09-01

    Supernumerary teeth are extra teeth or toothlike structures which may have either erupted or unerupted in addition to the 20 deciduous teeth and the 32 permanent teeth. Mesiodens is one of these located in the midline between the two central incisors. Their presence may give rise to a variety of clinical problems. This paper describes a rare case of palatal placed, inverted and impacted mesiodens associated to two supernumerary teeth which were detected during a radiographic examination for delayed eruption of permanent central incisors in the case of a healthy 8-year-old girl monitored at the oral surgery service while discussing the usefulness of cone beam computed tomography for accurate diagnosis and management.

  2. Accessory mental foramen: A rare anatomical variation detected by cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Marianna Guanaes Gomes; De Faro Valverde, Ludmila; Vidal, Manuela Torres Andion; Crusoe-Rebello, Ieda Margarida [Dept. of Oral Radiology, School of Dentistry, Federal University of Bahia, Salvador (Brazil)

    2015-03-15

    The mental foramen is a bilateral opening in the vestibular portion of the mandible through which nerve endings, such as the mental nerve, emerge. In general, the mental foramen is located between the lower premolars. This region is a common area for the placement of dental implants. It is very important to identify anatomical variations in presurgical imaging exams since damage to neurovascular bundles may have a direct influence on treatment success. In the hemimandible, the mental foramen normally appears as a single structure, but there are some rare reports on the presence and number of anatomical variations; these variations may include accessory foramina. The present report describes the presence of accessory mental foramina in the right mandible, as detected by cone-beam computed tomography before dental implant placement.

  3. Fast Scatter Artifacts Correction for Cone-Beam CT without System Modification and Repeat Scan

    CERN Document Server

    Zhao, Wei; Wang, Luyao

    2015-01-01

    We provide a fast and accurate scatter artifacts correction algorithm for cone beam CT (CBCT) imaging. The method starts with an estimation of coarse scatter profile for a set of CBCT images. A total-variation denoising algorithm designed specifically for Poisson signal is then applied to derive the final scatter distribution. Qualitatively and quantitatively evaluations using Monte Carlo (MC) simulations, experimental CBCT phantom data, and \\emph{in vivo} human data acquired for a clinical image guided radiation therapy were performed. Results show that the proposed algorithm can significantly reduce scatter artifacts and recover the correct HU within either projection domain or image domain. Further test shows the method is robust with respect to segmentation procedure.

  4. Commissioning and validation of BrainLAB cones for 6X FFF and 10X FFF beams on a Varian TrueBeam STx.

    Science.gov (United States)

    Wiant, David B; Terrell, Jonathon A; Maurer, Jacqueline M; Yount, Caroline L; Sintay, Benjamin J

    2013-11-04

    Small field dosimetry is a challenging task. The difficulties of small field measurements, particularly stereotactic field size measurements, are highlighted by the large interinstitution variability that can be observed for circular cone collimator commissioning measurements. We believe the best way to improve the consistency of small field measurements is to clearly document and share the results of small field measurements. In this work we report on the commissioning and validation of a BrainLAB cone system for 6 MV and 10 MV flattening filter-free (FFF) beams on a Varian TrueBeam STx. Commissioning measurements consisted of output factors, percent depth dose, and off-axis factor measurements with a diode. Validation measurements were made in a polystyrene slab phantom at depths of 5 cm, 10 cm, and 15 cm using radiochromic film. Output factors for the 6xFFF cones are 0.689, 0.790, 0.830, 0.871, 0.890, and 0.901 for 4 mm, 6 mm, 7.5 mm, 10 mm, 12.5 mm, and the 15 mm cones, respectively. Output factors for the 10xFFF cones are 0.566, 0.699, 0.756, 0.826, 0.864, and 0.888 for 4 mm, 6 mm, 7.5 mm, 10 mm, 12.5 mm, and the 15 mm cones, respectively. The full width half maximum values of the off-axis factors agreed with the nominal cone size to within 0.5 mm. Validation measurements showed an agreement of absolute dose between calculation and plan of < 3.6%, and an agreement of field sizes of ≤ 0.3 mm in all cases. Radiochromic film validation measurements show reasonable agreement with beam models for circular collimators based on diode commissioning measurements.

  5. Ion and electron beam effects on kinetic Alfven wave with general loss-cone distribution function-kinetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Nidhi; Mishra, Ruchi; Varma, P; Tiwari, M S [Department of Physics and Electronics, Dr H S Gour University, Sagar (MP) 470003 (India)

    2008-02-15

    This work studies the effect of ion and electron beam on kinetic Alfven wave (KAW) with general loss-cone distribution function. The kinetic theory has been adopted to evaluate the dispersion relation and damping rate of the wave in the presence of loss-cone distribution indices J. The variations in wave frequency {omega} and damping rate with perpendicular wave number k{sub perpendicular}{rho}{sub i} (k{sub perpendicular} is perpendicular wave number and {rho}{sub i} is ion gyroradius) and parallel wave number k{sub parallel} are studied. It is found that the distribution index J and ion beam velocity enhance the wave frequency at lower k{sub perpendicular}{rho}{sub i}, whereas the electron beam velocity enhances the wave frequency at higher k{sub perpendicular}{rho}{sub i}. The calculated values of frequency correspond to the observed values in the range 0.1-4 Hz. Increase in damping rate due to higher distribution indices J and ion beam velocity is observed. The effect of electron beam is to reduce the damping rate at higher k{sub perpendicular}{rho}{sub i}. The plasma parameters appropriate to plasma sheet boundary layer are used. The results may explain the transfer of Poynting flux from the magnetosphere to the ionosphere. It is also found that in the presence of the loss-cone distribution function the ion beam becomes a sensitive parameter to reduce the Poynting flux of KAW propagating towards the ionosphere.

  6. Evaluation of bone changes in the temporomandibular joint using cone beam CT

    Science.gov (United States)

    dos Anjos Pontual, ML; Freire, JSL; Barbosa, JMN; Frazão, MAG; dos Anjos Pontual, A; Fonseca da Silveira, MM

    2012-01-01

    Objective The aim of this study was to assess bone changes and mobility in temporomandibular joints (TMJs) using cone beam CT (CBCT) in a population sample in Recife, PE, Brazil. Methods The TMJ images of patients treated by a radiologist at a private dental radiology service over a period of 1 year were retrieved from the computer database and assessed using a computer with a 21-inch monitor and the iCAT Cone Beam 3D Dental Imaging System Workstation program (Imaging Sciences International, Hatfield, PA). The Pearson χ2 test was used to analyse the differences in percentage of bone changes among the categories of mobility (p ≤ 0.05). The McNemar test was used to compare the presence of bone changes in TMJs on the right and left sides (p ≤ 0.05). Results An adjusted logistic regression model was used to assess the effect of age and gender on the occurrence of bone changes (p ≤ 0.05). Bone changes were present in 227 (71%) patients. Age group and gender showed a statistically significant association with presence of bone changes (p ≤ 0.05). There was no significant difference between the right and left sides (p = 0.556) and in condylar mobility (p = 0.925) with regard to the presence of degenerative bone changes. Conclusions There is a high prevalence of degenerative bone alteration in TMJs, which is more frequent in women and mostly located in the condyle. The prevalence of degenerative bone changes increases with age. There is no correlation between condylar mobility and the presence of degenerative bony changes in TMJs. PMID:22184625

  7. In-treatment 4D cone-beam CT with image-based respiratory phase recognition.

    Science.gov (United States)

    Kida, Satoshi; Masutani, Yoshitaka; Yamashita, Hideomi; Imae, Toshikazu; Matsuura, Taeko; Saotome, Naoya; Ohtomo, Kuni; Nakagawa, Keiichi; Haga, Akihiro

    2012-07-01

    The use of respiration-correlated cone-beam computed tomography (4D-CBCT) appears to be crucial for implementing precise radiation therapy of lung cancer patients. The reconstruction of 4D-CBCT images requires a respiratory phase. In this paper, we propose a novel method based on an image-based phase recognition technique using normalized cross correlation (NCC). We constructed the respiratory phase by searching for a region in an adjacent projection that achieves the maximum correlation with a region in a reference projection along the cranio-caudal direction. The data on 12 lung cancer patients acquired just prior to treatment and on 3 lung cancer patients acquired during volumetric modulated arc therapy treatment were analyzed in the search for the effective area of cone-beam projection images for performing NCC with 12 combinations of registration area and segment size. The evaluation was done by a "recognition rate" defined as the ratio of the number of peak inhales detected with our method to that detected by eye (manual tracking). The average recognition rate of peak inhale with the most efficient area in the present method was 96.4%. The present method was feasible even when the diaphragm was outside the field of view. With the most efficient area, we reconstructed in-treatment 4D-CBCT by dividing the breathing signal into four phase bins; peak exhale, peak inhale, and two intermediate phases. With in-treatment 4D-CBCT images, it was possible to identify the tumor position and the tumor size in moments of inspiration and expiration, in contrast to in-treatment CBCT reconstructed with all projections.

  8. Region-of-interest cone beam computed tomography (ROI CBCT) with a high resolution CMOS detector

    Science.gov (United States)

    Jain, A.; Takemoto, H.; Silver, M. D.; Nagesh, S. V. S.; Ionita, C. N.; Bednarek, D. R.; Rudin, S.

    2015-03-01

    Cone beam computed tomography (CBCT) systems with rotational gantries that have standard flat panel detectors (FPD) are widely used for the 3D rendering of vascular structures using Feldkamp cone beam reconstruction algorithms. One of the inherent limitations of these systems is limited resolution (<3 lp/mm). There are systems available with higher resolution but their small FOV limits them to small animal imaging only. In this work, we report on region-of-interest (ROI) CBCT with a high resolution CMOS detector (75 μm pixels, 600 μm HR-CsI) mounted with motorized detector changer on a commercial FPD-based C-arm angiography gantry (194 μm pixels, 600 μm HL-CsI). A cylindrical CT phantom and neuro stents were imaged with both detectors. For each detector a total of 209 images were acquired in a rotational protocol. The technique parameters chosen for the FPD by the imaging system were used for the CMOS detector. The anti-scatter grid was removed and the incident scatter was kept the same for both detectors with identical collimator settings. The FPD images were reconstructed for the 10 cm x10 cm FOV and the CMOS images were reconstructed for a 3.84 cm x 3.84 cm FOV. Although the reconstructed images from the CMOS detector demonstrated comparable contrast to the FPD images, the reconstructed 3D images of the neuro stent clearly showed that the CMOS detector improved delineation of smaller objects such as the stent struts (~70 μm) compared to the FPD. Further development and the potential for substantial clinical impact are suggested.

  9. A One-Step Cone-Beam CT-Enabled Planning-to-Treatment Model for Palliative Radiotherapy-From Development to Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Rebecca K.S., E-mail: rebecca.wong@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Letourneau, Daniel; Varma, Anita [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Bissonnette, Jean Pierre; Fitzpatrick, David; Grabarz, Daniel; Elder, Christine [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Martin, Melanie; Bezjak, Andrea [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Panzarella, Tony [Department of Biostatistics, Princess Margaret Hospital, Toronto, Ontario (Canada); Gospodarowicz, Mary [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada)

    2012-11-01

    Purpose: To develop a cone-beam computed tomography (CT)-enabled one-step simulation-to-treatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry ({<=}2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CT-enabled planning process at the treatment unit. Phase C evaluated the online cone-beam CT-enabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n = 9) established the adequacy of cone-beam CT images for target definition. Phase B (n = 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% {+-} 11% and 97% {+-} 4%, respectively. The oncologist's decision to accept the plan under a time-pressured environment remained of high quality, with the cone-beam CT-generated treatment plan delivering at least 90% of the prescribed dose to 100% {+-} 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CT-generated treatment plan delivered at least 90% and at least 95% of dose to 98% {+-} 2% and 97% {+-} 5% of the PCT PTV, respectively. The mean time for the online planning and treatment process was 32.7 {+-} 4.0 minutes. Patient satisfaction was high, with a trend for superior satisfaction with the cone-beam CT-enabled process. Conclusions: The cone-beam

  10. A system to track skin dose for neuro-interventional cone-beam computed tomography (CBCT)

    Science.gov (United States)

    Vijayan, Sarath; Xiong, Zhenyu; Rudin, Stephen; Bednarek, Daniel R.

    2016-03-01

    The skin-dose tracking system (DTS) provides a color-coded illustration of the cumulative skin-dose distribution on a closely-matching 3D graphic of the patient during fluoroscopic interventions in real-time for immediate feedback to the interventionist. The skin-dose tracking utility of DTS has been extended to include cone-beam computed tomography (CBCT) of neurointerventions. While the DTS was developed to track the entrance skin dose including backscatter, a significant part of the dose in CBCT is contributed by exit primary radiation and scatter due to the many overlapping projections during the rotational scan. The variation of backscatter inside and outside the collimated beam was measured with radiochromic film and a curve was fit to obtain a scatter spread function that could be applied in the DTS. Likewise, the exit dose distribution was measured with radiochromic film for a single projection and a correction factor was determined as a function of path length through the head. Both of these sources of skin dose are added for every projection in the CBCT scan to obtain a total dose mapping over the patient graphic. Results show the backscatter to follow a sigmoidal falloff near the edge of the beam, extending outside the beam as far as 8 cm. The exit dose measured for a cylindrical CTDI phantom was nearly 10 % of the entrance peak skin dose for the central ray. The dose mapping performed by the DTS for a CBCT scan was compared to that measured with radiochromic film and a CTDI-head phantom with good agreement.

  11. SU-E-J-69: Evaluation of the Lens Dose On the Cone Beam IGRT Procedures

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    Palomo-Llinares, R; Gimeno-Olmos, J; Carmona Meseguer, V; Lliso-Valverde, F; Candela-Juan, C; Perez-Calatayud, J [Hospital La Fe, Valencia, Valencia (Spain); Pujades, M [National Dosimetry Center, Valencia, Valencia (Spain); Ballester, F [University of Valencia, Burjassot (Spain)

    2014-06-01

    Purpose: With the establishment of the IGRT as a standard technique, the extra dose that is given to the patients should be taken into account. Furthermore, it has been a recent decrease of the dose threshold in the lens, reduced to 0.5 Gy (ICRP ref 4825-3093-1464 on 21st April, 2011).The purpose of this work was to evaluate the extra dose that the lens is receive due to the Cone-Beam (CBCT) location systems in Head-and-Neck treatments. Methods: The On-Board Imaging (OBI) v 1.5 of the two Varian accelerators, one Clinac iX and one True Beam, were used to obtain the dose that this OBI version give to the lens in the Head-and-Neck location treatments. All CBCT scans were acquired with the Standard Dose Head protocol (100 kVp, 80 mA, 8 ms and 200 degree of rotation).The measurements were taken with thermoluminescence (TLD) EXTRAD (Harshaw) dosimeters placed in an anthropomorphic phantom over the eye and under 3 mm of bolus material to mimic the lens position. The center of the head was placed at the isocenter. To reduce TLD energy dependence, they were calibrated at the used beam quality. Results: The average lens dose at the lens in the OBI v 1.5 systems of the Clinac iX and the True Beam is 0.071 and 0.076 cGy/CBCT, respectively. Conclusions: The extra absorbed doses that receive the eye lenses due to one CBCT acquisition with the studied protocol is far below the new ICRP recommended threshold for the lens. However, the addition effect of several CBCT acquisition during the whole treatment should be taken into account.

  12. Low-dose 2.5 MV cone-beam computed tomography with thick CsI flat-panel imager.

    Science.gov (United States)

    Tang, Grace; Moussot, Christopher; Morf, Daniel; Seppi, Edward; Amols, Howard

    2016-07-08

    Most of the treatment units, both new and old models, are equipped with a megavoltage portal imager but its use for volumetric imaging is limited. This is mainly due to the poor image quality produced by the high-energy treatment beam (> 6MV). A linac at our center is equipped with a prototype 2.5 MV imaging beam. This study evaluates the feasibility of low-dose megavoltage cone-beam imaging with the 2.5MV beam and a thick cesium iodide detector, which is a high-efficiency imager. Basic imaging properties such as spatial resolution and modulation transfer function were assessed for the 2.5 MV prototype imaging system. For image quality and imaging dose, a series of megavoltage cone-beam scans were acquired for the head, thorax, and pelvis of an anthropomorphic phantom and were compared to kilovoltage cone-beam and 6X megavoltage cone-beam images. To demonstrate the advantage of MV imaging, a phantom with metallic inserts was scanned and the image quality was compared to CT and kilovoltage cone-beam scans. With a lower energy beam and higher detector efficiency, the 2.5 MV imaging system generally yields better image quality than does the 6 MV imaging system with the conventional MV imager. In particular, with the anthropomorphic phantom studies, the contrast to noise of bone to tissue is generally improved in the 2.5 MV images compared to 6 MV. With an image quality sufficient for bony alignment, the imaging dose for 2.5 MV cone-beam images is 2.4-3.4 MU compared to 26 MU in 6 MV cone-beam scans for the head, thorax, and pelvis regions of the phantom. Unlike kilovoltage cone-beam, the 2.5 MV imaging system does not suffer from high-Z image artifacts. This can be very useful for treatment planning in cases where high-Z prostheses are present.

  13. Volume-of-interest cone-beam CT using a 2.35 MV beam generated with a carbon target.

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    Robar, James L; Parsons, David; Berman, Avery; Macdonald, Alex

    2012-07-01

    This is a proof-of-concept study addressing volume of interest (VOI) cone beam CT (CBCT) imaging using an x-ray beam produced by 2.35 MeV electrons incident on a carbon linear accelerator target. Methodology is presented relevant to VOI CBCT image acquisition and reconstruction. Sample image data are given to demonstrate and compare two approaches to minimizing artifacts arising from reconstruction with truncated projections. Dosimetric measurements quantify the potential dose reduction of VOI acquisition relative to full-field CBCT. The dependence of contrast-to-noise ratio (CNR) on VOI dimension is investigated. A paradigm is presented linking the treatment planning process with the imaging technique, allowing definition of an imaging VOI to be tailored to the geometry of the patient. Missing data in truncated projection images are completed using a priori information in the form of digitally reconstructed radiographs (DRRs) generated from the planning CT set. This method is compared to a simpler technique of extrapolating truncated projection data prior to reconstruction. The utility of these approaches is shown through imaging of a geometric phantom and the head-and-neck section of a lamb. The total scatter factor of the 2.35 MV∕carbon beam on field size is measured and compared to a standard therapeutic beam to estimate the comparative dose reduction inside the VOI. Thermoluminescent dosimeters and Gafchromic film measurements are used to compare the imaging dose distributions for the 2.35 MV∕carbon beam between VOI and full-field techniques. The dependence of CNR on VOI dimension is measured for VOIs ranging from 4 to 15 cm diameter. Without compensating for missing data outside of truncated projections prior to reconstruction, pronounced boundary artifacts are present, in three dimensions, within 2-3 cm of the edges of the VOI. These artifacts, as well as cupping inside the VOI, can be reduced substantially using either the DRR filling or extrapolation

  14. The use of cone beam computed tomography for the assessment of trichorhinophalangeal syndrome, type I – a case report

    Science.gov (United States)

    Ghoneima, Ahmed; Sachdeva, Kanwar; Hartsfield, James; Weaver, David; Kula, Katherine

    2016-01-01

    Trichorhinophalangeal syndrome type I is a rare autosomal dominant disorder characterized by cone-shaped epiphysis, sparse fine hair, pear-shaped nose and variable growth retardation. The typical craniofacial features include thin upper lip, elongated philtrum, large outstanding ears, shortened posterior facial height associated with short mandibular ramus and reduced and superiorly deflected posterior cranial base. This report describes a 17-year-old male patient with trichorhinophalangeal syndrome type I and a detailed description of the craniofacial radiographic findings, including the use of cone beam computed tomography images for determination of the airway and temporomandibular joint discrepancies. PMID:23524547

  15. Use of Monte Carlo simulation software for calculating effective dose in cone beam computed tomography

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    Gomes B, W. O., E-mail: wilsonottobatista@gmail.com [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho 40301-015, Salvador de Bahia (Brazil)

    2016-10-15

    This study aimed to develop a geometry of irradiation applicable to the software PCXMC and the consequent calculation of effective dose in applications of the Computed Tomography Cone Beam (CBCT). We evaluated two different CBCT equipment s for dental applications: Care stream Cs 9000 3-dimensional tomograph; i-CAT and GENDEX GXCB-500. Initially characterize each protocol measuring the surface kerma input and the product kerma air-area, P{sub KA}, with solid state detectors RADCAL and PTW transmission chamber. Then we introduce the technical parameters of each preset protocols and geometric conditions in the PCXMC software to obtain the values of effective dose. The calculated effective dose is within the range of 9.0 to 15.7 μSv for 3-dimensional computer 9000 Cs; within the range 44.5 to 89 μSv for GXCB-500 equipment and in the range of 62-111 μSv for equipment Classical i-CAT. These values were compared with results obtained dosimetry using TLD implanted in anthropomorphic phantom and are considered consistent. Os effective dose results are very sensitive to the geometry of radiation (beam position in mathematical phantom). This factor translates to a factor of fragility software usage. But it is very useful to get quick answers to regarding process optimization tool conclusions protocols. We conclude that use software PCXMC Monte Carlo simulation is useful assessment protocols for CBCT tests in dental applications. (Author)

  16. A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

    Directory of Open Access Journals (Sweden)

    Kuo Men

    2015-01-01

    Full Text Available Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT device. Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images. Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously. Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

  17. Fractionated changes in prostate cancer radiotherapy using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung City, Taiwan (China); Chou, Kuei-Ting [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan (China); Yang, Shih-Neng [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan (China); Department of Biomedical Informatics, Asia University, Taichung City, Taiwan (China); Chang, Chih-Kai [Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung City, Taiwan (China); Liang, Ji-An [Department of Radiation Oncology, China Medical University Hospital, Taichung City, Taiwan (China); Zhang, Geoffrey [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL (United States)

    2015-10-01

    The high mobility of the bladder and the rectum causes uncertainty in radiation doses prescribed to patients with prostate cancer who undergo radiotherapy (RT) multifraction treatments. The purpose of this study was to estimate the dose received by the bladder, rectum, and prostate from multifraction treatments using daily cone-beam computed tomography (CBCT). Overall, 28 patients with prostate cancer who planned to receive radiation treatments were enrolled in the study. The acquired CBCT before the treatment delivery was registered with the planning CT to map the dose distribution used in the treatment plan for estimating the received dose during clinical treatment. For all 28 patients with 112 data sets, the mean percentage differences (± standard deviation) in the volume and radiation dose were 44% (± 41) and 18% (± 17) for the bladder, 20% (± 21) and 2% (± 2) for the prostate, and 36% (± 29) and 22% (± 15) for the rectum, respectively. Substantial differences between the volumes and radiation dose and those specified in treatment plans were observed. Besides the use of image-guided RT to improve patient setup accuracy, further consideration of large changes in bladder and rectum volumes is strongly suggested when using external beam radiation for prostate cancer.

  18. X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT

    Directory of Open Access Journals (Sweden)

    Sorapong Aootaphao

    2016-01-01

    Full Text Available Soft tissue images from portable cone beam computed tomography (CBCT scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.

  19. Cone beam computed tomography in paediatric dentistry: overview of recent literature.

    Science.gov (United States)

    Aps, J K M

    2013-06-01

    The use of cone beam computed tomography (CBCT) in paediatric dentistry has been mentioned in numerous publications and case reports. The indications for the use of CBCT in paediatric dentistry, however, have not yet been properly addressed. On the other hand, the three basic principles of radiation protection (justification, limitation and optimisation) should suffice. A review of the current literature was used to assess the indications and contra-indications for the use of CBCT in paediatric dentistry. Paramount is the fact that CBCT generates a higher effective dose to the tissues than traditional dental radiographic exposures do. The effective radiation dose should not be underestimated, especially not in children, who are much more susceptible to stochastic biological effects. The thyroid gland in particular should be kept out of the primary beam as much as possible. As with any other radiographical technique, routine use of CBCT is not acceptable clinical practice. CBCT certainly has a place in paediatric dentistry, but its use must be justified on a patient case individual basis.

  20. Hybrid simulation of scatter intensity in industrial cone-beam computed tomography

    Science.gov (United States)

    Thierry, R.; Miceli, A.; Hofmann, J.; Flisch, A.; Sennhauser, U.

    2009-01-01

    A cone-beam computed tomography (CT) system using a 450 kV X-ray tube has been developed to challenge the three-dimensional imaging of parts of the automotive industry in short acquisition time. Because the probability of detecting scattered photons is high regarding the energy range and the area of detection, a scattering correction becomes mandatory for generating reliable images with enhanced contrast detectability. In this paper, we present a hybrid simulator for the fast and accurate calculation of the scattering intensity distribution. The full acquisition chain, from the generation of a polyenergetic photon beam, its interaction with the scanned object and the energy deposit in the detector is simulated. Object phantoms can be spatially described in form of voxels, mathematical primitives or CAD models. Uncollided radiation is treated with a ray-tracing method and scattered radiation is split into single and multiple scattering. The single scattering is calculated with a deterministic approach accelerated with a forced detection method. The residual noisy signal is subsequently deconvoluted with the iterative Richardson-Lucy method. Finally the multiple scattering is addressed with a coarse Monte Carlo (MC) simulation. The proposed hybrid method has been validated on aluminium phantoms with varying size and object-to-detector distance, and found in good agreement with the MC code Geant4. The acceleration achieved by the hybrid method over the standard MC on a single projection is approximately of three orders of magnitude.

  1. Interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme

    Science.gov (United States)

    Saedjalil, N.; Mehrangiz, M.; Jafari, S.; Ghasemizad, A.

    2016-06-01

    In this paper, the interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme has been presented. We propose here to merge a plasma-loaded cone with the precompressed DT target in order to strongly focus the incident laser beam on the core to improve the fusion gain. The WKB approximation is used to derive a differential equation that governs the evolution of beamwidth of the incident laser beam with the distance of propagation in the plasma medium. The effects of initial plasma and laser parameters, such as initial plasma electron temperature, initial radius of the laser beam, initial laser beam intensity and plasma density, on self-focusing and defocusing of the Gaussian laser beam have been studied. Numerical results indicate that with increasing the plasma frequency (or plasma density) in the cone, the laser beam will be self-focused noticeably, while for a thinner laser beam (with small radius), it will diverge as propagate in the cone. By evaluating the energy deposition of the relativistic electron ignitors in the fuel, the importance of electron transportation in the cone-attached shell was demonstrated. Moreover, by lessening the least energy needed for ignition, the electrons coupling with the pellet enhances. Therefore, it increases the fusion efficiency. In this scheme, with employing a plasma-loaded cone, the fusion process improves without needing an ultrahigh-intensity laser beam in a conventional ICF.

  2. Algorithm for X-ray scatter, beam-hardening, and beam profile correction in diagnostic (kilovoltage) and treatment (megavoltage) cone beam CT.

    Science.gov (United States)

    Maltz, Jonathan S; Gangadharan, Bijumon; Bose, Supratik; Hristov, Dimitre H; Faddegon, Bruce A; Paidi, Ajay; Bani-Hashemi, Ali R

    2008-12-01

    Quantitative reconstruction of cone beam X-ray computed tomography (CT) datasets requires accurate modeling of scatter, beam-hardening, beam profile, and detector response. Typically, commercial imaging systems use fast empirical corrections that are designed to reduce visible artifacts due to incomplete modeling of the image formation process. In contrast, Monte Carlo (MC) methods are much more accurate but are relatively slow. Scatter kernel superposition (SKS) methods offer a balance between accuracy and computational practicality. We show how a single SKS algorithm can be employed to correct both kilovoltage (kV) energy (diagnostic) and megavoltage (MV) energy (treatment) X-ray images. Using MC models of kV and MV imaging systems, we map intensities recorded on an amorphous silicon flat panel detector to water-equivalent thicknesses (WETs). Scattergrams are derived from acquired projection images using scatter kernels indexed by the local WET values and are then iteratively refined using a scatter magnitude bounding scheme that allows the algorithm to accommodate the very high scatter-to-primary ratios encountered in kV imaging. The algorithm recovers radiological thicknesses to within 9% of the true value at both kV and megavolt energies. Nonuniformity in CT reconstructions of homogeneous phantoms is reduced by an average of 76% over a wide range of beam energies and phantom geometries.

  3. Comparison measurements of DQE for two flat panel detectors: fluoroscopic detector vs. cone beam CT detector

    Science.gov (United States)

    Betancourt Benítez, Ricardo; Ning, Ruola; Conover, David

    2006-03-01

    The physical performance of two flat panel detectors (FPD) has been evaluated using a standard x-ray beam quality set by IEC, namely RQA5. The FPDs evaluated in this study are based on an amorphous silicon photodiode array that is coupled to a thallium-doped Cesium Iodide scintillator and to a thin film transistor (TFT) array. One detector is the PaxScan 2520 that is designed for fluoro imaging, and has a small dynamic range and a large image lag. The other detector is the PaxScan 4030CB that is designed for cone beam CT, and has a large dynamic range (>16-bit), a reduced image lag and many imaging modes. Varian Medical Systems manufactured both detectors. The linearity of the FPDs was investigated by using an ionization chamber and aluminum filtration in order to obtain the beam quality. Since the FPDs are used in fluoroscopic mode, image lag of the FPD was measured in order to investigate its effect on this study, especially its effect on DQE. The spatial resolution of the FPDs was determined by obtaining the pre-sampling modulation transfer function for each detector. A sharp edge was used in accordance to IEC 62220-1. Next, the Normalized Noise Power Spectrum (NNPS) was calculated for various exposures levels at RQA5 radiation quality. Finally, the DQE of each FPD was obtained with a modified version of the international standard set by IEC 62220-1. The results show that the physical performance in DQE and MTF of the PaxScan 4030CB is superior to that of PaxScan2520.

  4. Dosimetric characterization and application of an imaging beam line with a carbon electron target for megavoltage cone beam computed tomography.

    Science.gov (United States)

    Flynn, Ryan T; Hartmann, Julia; Bani-Hashemi, Ali; Nixon, Earl; Alfredo, R; Siochi, C; Pennington, Edward C; Bayouth, John E

    2009-06-01

    Imaging dose from megavoltage cone beam computed tomography (MVCBCT) can be significantly reduced without loss of image quality by using an imaging beam line (IBL), with no flattening filter and a carbon, rather than tungsten, electron target. The IBL produces a greater keV-range x-ray fluence than the treatment beam line (TBL), which results in a more optimal detector response. The IBL imaging dose is not necessarily negligible, however. In this work an IBL was dosimetrically modeled with the Philips Pinnacle3 treatment planning system (TPS), verified experimentally, and applied to clinical cases. The IBL acquisition dose for a 200 degrees gantry rotation was verified in a customized acrylic cylindrical phantom at multiple imaging field sizes with 196 ion chamber measurements. Agreement between the measured and calculated IBL dose was quantified with the 3D gamma index. Representative IBL and TBL imaging dose distributions were calculated for head and neck and prostate patients and included in treatment plans using the imaging dose incorporation (IDI) method. Surface dose was measured for the TBL and IBL for four head and neck cancer patients with MOSFETs. The IBL model, when compared to the percentage depth dose and profile measurements, had 97% passing gamma indices for dosimetric and distance acceptance criteria of 3%, 3 mm, and 100% passed for 5.2%, 5.2 mm. For the ion chamber measurements of phantom image acquisition dose, the IBL model had 93% passing gamma indices for acceptance criteria of 3%, 3 mm, and 100% passed for 4%, 4 mm. Differences between the IBL- and TBL-based IMRT treatment plans created with the IDI method were dosimetrically insignificant for both the prostate and head and neck cases. For IBL and TBL beams with monitor unit values that would result in the delivery of the same dose to the depth of maximum dose under standard calibration conditions, the IBL imaging surface dose was higher than the TBL imaging surface dose by an average of 18

  5. Task-driven image acquisition and reconstruction in cone-beam CT.

    Science.gov (United States)

    Gang, Grace J; Stayman, J Webster; Ehtiati, Tina; Siewerdsen, Jeffrey H

    2015-04-21

    This work introduces a task-driven imaging framework that incorporates a mathematical definition of the imaging task, a model of the imaging system, and a patient-specific anatomical model to prospectively design image acquisition and reconstruction techniques to optimize task performance. The framework is applied to joint optimization of tube current modulation, view-dependent reconstruction kernel, and orbital tilt in cone-beam CT. The system model considers a cone-beam CT system incorporating a flat-panel detector and 3D filtered backprojection and accurately describes the spatially varying noise and resolution over a wide range of imaging parameters in the presence of a realistic anatomical model. Task-based detectability index (d') is incorporated as the objective function in a task-driven optimization of image acquisition and reconstruction techniques. The orbital tilt was optimized through an exhaustive search across tilt angles ranging ± 30°. For each tilt angle, the view-dependent tube current and reconstruction kernel (i.e. the modulation profiles) that maximized detectability were identified via an alternating optimization. The task-driven approach was compared with conventional unmodulated and automatic exposure control (AEC) strategies for a variety of imaging tasks and anthropomorphic phantoms. The task-driven strategy outperformed the unmodulated and AEC cases for all tasks. For example, d' for a sphere detection task in a head phantom was improved by 30% compared to the unmodulated case by using smoother kernels for noisy views and distributing mAs across less noisy views (at fixed total mAs) in a manner that was beneficial to task performance. Similarly for detection of a line-pair pattern, the task-driven approach increased d' by 80% compared to no modulation by means of view-dependent mA and kernel selection that yields modulation transfer function and noise-power spectrum optimal to the task. Optimization of orbital tilt identified the tilt

  6. Quantification of dental prostheses on cone-beam CT images by the Taguchi method.

    Science.gov (United States)

    Kuo, Rong-Fu; Fang, Kwang-Ming; Ty, Wong; Hu, Chia Yu

    2016-01-08

    The gray values accuracy of dental cone-beam computed tomography (CBCT) is affected by dental metal prostheses. The distortion of dental CBCT gray values could lead to inaccuracies of orthodontic and implant treatment. The aim of this study was to quantify the effect of scanning parameters and dental metal prostheses on the accuracy of dental cone-beam computed tomography (CBCT) gray values using the Taguchi method. Eight dental model casts of an upper jaw including prostheses, and a ninth prosthesis-free dental model cast, were scanned by two dental CBCT devices. The mean gray value of the selected circular regions of interest (ROIs) were measured using dental CBCT images of eight dental model casts and were compared with those measured from CBCT images of the prosthesis-free dental model cast. For each image set, four consecutive slices of gingiva were selected. The seven factors (CBCTs, occlusal plane canting, implant connection, prosthesis position, coping material, coping thickness, and types of dental restoration) were used to evaluate scanning parameter and dental prostheses effects. Statistical methods of signal to noise ratio (S/N) and analysis of variance (ANOVA) with 95% confidence were applied to quantify the effects of scanning parameters and dental prostheses on dental CBCT gray values accuracy. For ROIs surrounding dental prostheses, the accuracy of CBCT gray values were affected primarily by implant connection (42%), followed by type of restoration (29%), prostheses position (19%), coping material (4%), and coping thickness (4%). For a single crown prosthesis (without support of implants) placed in dental model casts, gray value differences for ROIs 1-9 were below 12% and gray value differences for ROIs 13-18 away from pros-theses were below 10%. We found the gray value differences set to be between 7% and 8% for regions next to a single implant-supported titanium prosthesis, and between 46% and 59% for regions between double implant

  7. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    Science.gov (United States)

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  8. Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2014-03-01

    Full Text Available Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT. We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1 FDK reconstruction using raw projection data; 2 Rigid Registration of planning CT to the FDK results; 3 MC scatter calculation at sparse view angles using the planning CT; 4 Interpolation of the calculated scatter signals to other angles; 5 Removal of scatter from the raw projections; 6 FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this

  9. Low-contrast visualization in megavoltage cone-beam CT at one beam pulse per projection using thick segmented scintillators

    Science.gov (United States)

    El-Mohri, Youcef; Antonuk, Larry E.; Zhao, Qihua; Choroszucha, Richard B.; Wang, Yi

    2010-04-01

    Megavoltage cone-beam computed tomography (MV CBCT) using an electronic portal imaging device (EPID) is a highly promising technique for providing valuable volumetric information for image guidance in radiotherapy. However, active matrix flat-panel imagers (AMFPIs), which are the established gold standard in portal imaging, require a relatively large dose to create images that are clinically useful. This is a consequence of the inefficiency of the phosphor screens employed in conventional MV AMFPIs, which utilize only ~2% of the incident radiation at 6 MV. Fortunately, the incorporation of thick, segmented scintillators can significantly improve the performance of MV AMFPIs, leading to improved image quality for projection imaging at extremely low dose. It is therefore of interest to explore the performance of such thick scintillators for MV CBCT toward the goal of soft-tissue contrast visualization. In this study, prototype AMFPIs incorporating segmented scintillators based on CsI:Tl and BGO crystals with thicknesses ranging from ~11 to 25 mm have been constructed and evaluated. Each prototype incorporates a detector consisting of a matrix of 120 × 60 scintillator elements separated by reflective septal walls, with an element-to-element pitch of 1.016 mm, coupled to an overlying ~1 mm thick Cu plate. The prototype AMFPIs were incorporated into a bench-top CBCT system, allowing the acquisition of tomographic images of a contrast phantom using a 6 MV radiotherapy photon beam. The phantom consists of a water-equivalent (solid water) cylinder, embedded with tissue-equivalent inserts having electron densities, relative to water, varying from ~0.43 to ~1.47. Reconstructed images of the phantom were obtained down to the lowest available dose (one beam pulse per projection), corresponding to a total scan dose of ~4 cGy using 180 projections. In this article, reconstructed images, contrast, noise and contrast-to-noise ratio for the tissue-equivalent objects using the

  10. Patient dose from kilovoltage cone beam computed tomography imaging in radiation therapy.

    Science.gov (United States)

    Islam, Mohammad K; Purdie, Thomas G; Norrlinger, Bernhard D; Alasti, Hamideh; Moseley, Douglas J; Sharpe, Michael B; Siewerdsen, Jeffrey H; Jaffray, David A

    2006-06-01

    Kilovoltage cone-beam computerized tomography (kV-CBCT) systems integrated into the gantry of linear accelerators can be used to acquire high-resolution volumetric images of the patient in the treatment position. Using on-line software and hardware, patient position can be determined accurately with a high degree of precision and, subsequently, set-up parameters can be adjusted to deliver the intended treatment. While the patient dose due to a single volumetric imaging acquisition is small compared to the therapy dose, repeated and daily image guidance procedures can lead to substantial dose to normal tissue. The dosimetric properties of a clinical CBCT system have been studied on an Elekta linear accelerator (Synergy RP, XVI system) and additional measurements performed on a laboratory system with identical geometry. Dose measurements were performed with an ion chamber and MOSFET detectors at the center, periphery, and surface of 30 and 16-cm-diam cylindrical shaped water phantoms, as a function of x-ray energy and longitudinal field-of-view (FOV) settings of 5,10,15, and 26 cm. The measurements were performed for full 360 degrees CBCT acquisition as well as for half-rotation scans for 120 kVp beams using the 30-cm-diam phantom. The dose at the center and surface of the body phantom were determined to be 1.6 and 2.3 cGy for a typical imaging protocol, using full rotation scan, with a technique setting of 120 kVp and 660 mAs. The results of our measurements have been presented in terms of a dose conversion factor fCBCT, expressed in cGy/R. These factors depend on beam quality and phantom size as well as on scan geometry and can be utilized to estimate dose for any arbitrary mAs setting and reference exposure rate of the x-ray tube at standard distance. The results demonstrate the opportunity to manipulate the scanning parameters to reduce the dose to the patient by employing lower energy (kVp) beams, smaller FOV, or by using half-rotation scan.

  11. Impacted lower third molar fused with a supernumerary tooth--diagnosis and treatment planning using cone-beam computed tomography.

    Science.gov (United States)

    Ferreira-Junior, Osny; de Avila, Luciana Dorigatti; Sampieri, Marcelo Bonifácio da Silva; Dias-Ribeiro, Eduardo; Chen, Wei-liang; Fan, Song

    2009-12-01

    This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan's radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography-which provides precise three-dimensional information-was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomography.

  12. A new method to determine the projected coordinate origin of a cone-beam CT system using elliptical projection

    Institute of Scientific and Technical Information of China (English)

    YANG Min; JIN Xu-Ling; LI Bao-Lei

    2010-01-01

    In order to determine the projected coordinate origin in the cone-beam CT scanning system with respect to the Feldkamp-Davis-Kress(FDK)algorithm,we propose a simple yet feasible method to accurately measure the projected coordinate origin.This method was established on the basis of the theory that the projection of a spherical object in the cone-beam field is an ellipse.We first utilized image processing and the least square estimation method to get each major axis of the elliptical Digital Radiography(DR)projections of a group of spherical objects.Then we determined the intersection point of the group of major axis by solving an over-determined equation set that was composed by the major axis equations of all the elliptical projections.Based on the experimental results,this new method was proved to be easy to implement in practical scanning systems with high accuracy and anti-noise capability.

  13. Small peripheral developing odontoma of the maxilla in a 3-year-old patient depicted on cone-beam tomograms.

    Science.gov (United States)

    Friedrich, Reinhard E; Fuhrmann, Andreas; Scheuer, Hanna A; Zustin, Jozef

    2010-01-01

    A 3-year-old male patient was referred to the Maxillofacial Surgery Clinic due to a painless swelling of the right palatal region. Conventional radiographs revealed no alteration of the dentition and did not delineate a lesion in the region of interest. Cone-beam tomography depicted small radiopaque, extraosseous deposits inside the palatal space. Histological examination revealed a minute mixed epithelial-mesenchymal lesion of odontogenic origin. We made the diagnosis of a peripheral developing odontoma, taking into consideration the components and arrangements of structures of the lesion. Early intervention is advisable to prevent these odontogenic lesions from eventually deforming the jaw and displacing adjacent teeth. Cone-beam tomography was a valuable pre-operative diagnostic tool to assess the lesion as being composed in part of hard tissue.

  14. Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Adam K., E-mail: Adam.K.Glaser@dartmouth.edu, E-mail: Brian.W.Pogue@dartmouth.edu; Andreozzi, Jacqueline M. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Zhang, Rongxiao [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Pogue, Brian W., E-mail: Adam.K.Glaser@dartmouth.edu, E-mail: Brian.W.Pogue@dartmouth.edu [Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Gladstone, David J. [Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States)

    2015-07-15

    Purpose: To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). Methods: An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp–Davis–Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. Results: 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm{sup 3} volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%–99% pass fraction depending on the chosen threshold dose. Conclusions: The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.

  15. Bone mineral density in cone beam computed tomography:Only a few shades of gray

    Institute of Scientific and Technical Information of China (English)

    Marcio; José; da; Silva; Campos; Thainara; Salgueiro; de; Souza; Sergio; Luiz; Mota; Júnior; Marcelo; Reis; Fraga; Robert; Willer; Farinazzo; Vitral

    2014-01-01

    Cone beam computed tomography(CBCT) has often been used to determine the quality of craniofacial bone structures through the determination of mineral density, which is based on gray scales of the images obtained. However, there is no consensus regarding the accuracy of the determination of the gray scales in these exams. This study aims to provide a literature review concerning the reliability of CBCT to determine bone mineral density. The gray values obtained with CBCT show a linear relationship with the attenuation coefficients of the materials, Hounsfield Units values obtained with medical computed tomography, and density values from dual energy X-ray absorciometry. However, errors are expected when CBCT images are used to define the quality of the scanned structures be-cause these images show inconsistencies and arbitrari-ness in the gray values, particularly when related to abrupt change in the density of the object, X-ray beam hardening effect, scattered radiation, projection data discontinuity-related effect, differences between CBCTdevices, changes in the volume of the field of view(FOV), and changes in the relationships of size and position between the FOV and the object evaluated. A few methods of mathematical correction of the gray scales in CBCT have been proposed; however, they do not generate consistent values that are independent of the devices and their configurations or of the scanned objects. Thus, CBCT should not be considered the ex-amination of choice for the determination of bone and soft tissue mineral density at the current stage, par-ticularly when values obtained are to be compared to predetermined standard values. Comparisons between symmetrically positioned structures inside the FOV and in relation to the exomass of the object, as it occurs with the right and left sides of the skull, seem to be viable because the effects on the gray scale in the re-gions of interest are the same.

  16. Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation.

    Science.gov (United States)

    Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

    2015-07-01

    The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal ('tubular' geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal ('pancake' geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry, respectively.

  17. Characterization of Scattered X-Ray Photons in Dental Cone-Beam Computed Tomography.

    Directory of Open Access Journals (Sweden)

    Ching-Ching Yang

    Full Text Available Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT, which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction.Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and the projection obtained by extrapolating the model fitted to the raw projections acquired with 2 different sizes of axial field-of-view (FOV. The function for curve fitting was optimized by using Monte Carlo simulation. To validate the proposed method, an anthropomorphic phantom and a water-filled cylindrical phantom with rod inserts simulating different tissue materials were scanned using 120 kVp, 5 mA and 9-second scanning time covering an axial FOV of 4 cm and 13 cm. The detectability of the CT image was evaluated by calculating the contrast-to-noise ratio (CNR.Beam hardening and cupping artifacts were observed in CBCT images without scatter correction, especially in those acquired with 13 cm FOV. These artifacts were reduced in CBCT images corrected by the proposed method, demonstrating its efficacy on scatter correction. After scatter correction, the image quality of CBCT was improved in terms of target detectability which was quantified as the CNR for rod inserts in the cylindrical phantom.Hopefully the calculations performed in this work can provide a route to reach a high level of diagnostic image quality for CBCT imaging used in oral and maxillofacial structures whilst ensuring patient dose as low as reasonably achievable, which may ultimately make CBCT scan a reliable and safe tool in clinical practice.

  18. Electron beam radiotherapy for tongue cancer using an intra-oral cone.

    Science.gov (United States)

    Kakimoto, Naoya; Murakami, Shumei; Nakatani, Atsutoshi; Yoshioka, Yasuo; Shimizutani, Kimishige; Furukawa, Souhei

    2012-05-01

    To explain the adaptation technique using an intra-oral cone (IOC) for radiation therapy, and to determine the optimal schedule resulting in a high local control rate and an acceptable complication rate using direct electron beam radiation for the treatment of tongue cancer. Thirty patients with the tongue cancer (T1:T2:T3=16:11:3) were treated with 6-15 MeV electron radiation using an IOC. Twenty-six patients were treated with electron radiation using an IOC with or without an excisional biopsy. The other four patients were treated with a combination of the external beam radiation and electron radiation using the IOC. In order to formulate a safe and effective treatment program, we calculated the biologically effective dose (BED). The two- and five-year local control rates for all patients were 63% and 52%, respectively. The two- and five-year overall survival rates for all patients were 73% and 69%, respectively. Local control was achieved in 12 of 15 patients who were irradiated with a BED of 90.9 Gy(10) or more, whereas it was not achieved in nine of the 15 patients who were treated with less than a BED of 90.9 Gy(10) (p=0.03). The application of electron radiation using an IOC for the treatment of tongue cancer provides acceptable local control and adverse effect rates, especially for elderly patients considered to be high risk for complications from anesthesia. The optimum BED(10) value for the treatment of early tongue cancer using the IOC technique appears to be at least 90.9 Gy(10). Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. An investigation into factors affecting electron density calibration for a megavoltage cone-beam CT system.

    Science.gov (United States)

    Hughes, Jessica; Holloway, Lois C; Quinn, Alexandra; Fielding, Andrew

    2012-09-06

    There is a growing interest in the use of megavoltage cone-beam computed tomography (MV CBCT) data for radiotherapy treatment planning. To calculate accurate dose distributions, knowledge of the electron density (ED) of the tissues being irradiated is required. In the case of MV CBCT, it is necessary to determine a calibration-relating CT number to ED, utilizing the photon beam produced for MV CBCT. A number of different parameters can affect this calibration. This study was undertaken on the Siemens MV CBCT system, MVision, to evaluate the effect of the following parameters on the reconstructed CT pixel value to ED calibration: the number of monitor units (MUs) used (5, 8, 15 and 60 MUs), the image reconstruction filter (head and neck, and pelvis), reconstruction matrix size (256 by 256 and 512 by 512), and the addition of extra solid water surrounding the ED phantom. A Gammex electron density CT phantom containing EDs from 0.292 to 1.707 was imaged under each of these conditions. The linear relationship between MV CBCT pixel value and ED was demonstrated for all MU settings and over the range of EDs. Changes in MU number did not dramatically alter the MV CBCT ED calibration. The use of different reconstruction filters was found to affect the MV CBCT ED calibration, as was the addition of solid water surrounding the phantom. Dose distributions from treatment plans calculated with simulated image data from a 15 MU head and neck reconstruction filter MV CBCT image and a MV CBCT ED calibration curve from the image data parameters and a 15 MU pelvis reconstruction filter showed small and clinically insignificant differences. Thus, the use of a single MV CBCT ED calibration curve is unlikely to result in any clinical differences. However, to ensure minimal uncertainties in dose reporting, MV CBCT ED calibration measurements could be carried out using parameter-specific calibration measurements.

  20. The development and role of megavoltage cone beam computerized tomography in radiation oncology

    Science.gov (United States)

    Morin, Olivier

    External beam radiation therapy has now the ability to deliver doses that conform tightly to a tumor volume. The steep dose gradients planned in these treatments make it increasingly important to reproduce the patient position and anatomy at each treatment fraction. For this reason, considerable research now focuses on in-room three-dimensional imaging. This thesis describes the first clinical megavoltage cone beam computed tomography (MVCBCT) system, which utilizes a conventional linear accelerator equipped with an amorphous silicon flat panel detector. The document covers the system development and investigation of its clinical applications over the last 4-5 years. The physical performance of the system was evaluated and optimized for soft-tissue contrast resolution leading to recommendations of imaging protocols to use for specific clinical applications and body sites. MVCBCT images can resolve differences of 5% in electron density for a mean dose of 9 cGy. Hence, the image quality of this system is sufficient to differentiate some soft-tissue structures. The absolute positioning accuracy with MVCBCT is better than 1 mm. The accuracy of isodose lines calculated using MVCBCT images of head and neck patients is within 3% and 3 mm. The system shows excellent stability in image quality, CT# calibration, radiation exposure and absolute positioning over a period of 8 months. A procedure for MVCBCT quality assurance was developed. In our clinic, MVCBCT has been used to detect non rigid spinal cord distortions, to position a patient with a paraspinous tumor close to metallic hardware, to position prostate cancer patients using gold markers or soft-tissue landmarks, to monitor head and neck anatomical changes and their dosimetric consequences, and to complement the convention CT for treatment planning in presence of metallic implants. MVCBCT imaging is changing the clinical practice of our department by increasingly revealing patient-specific errors. New verification

  1. Evaluation of Root Fracture in endodontically treated Teeth using Cone Beam Computed Tomography.

    Science.gov (United States)

    Tiepo, Mariana; Magrin, Gabriel; Kovalik, Ana C; Marmora, Belkiss; Silva, Milena F; Raitz, Ricardo

    2017-02-01

    Our objective was to perform an in vitro evaluation of root fracture in endodontically treated teeth using two cone beam computed tomography (CBCT) machines. The sample comprised 86 single-rooted human premolars that had been fractured by a universal testing machine. The tomographic images were acquired using an Orthopantomograph OP300(®) and an Orthophos XG 3D(®) and evaluated by three examiners, by means of specific software. The teeth were classified into presence or absence of root fracture, then the root third where the fracture occurred, was determined. With regard to the detection of the fracture, the Kappa statistic was used for intra and interexaminer repro-ducibility at two distinct points in time. Chi-squared test was employed to analyze the sensitivity and specificity of the two tomographs (p < 0.05). The results showed a good or excellent Kappa index between examiners. As for the absolute frequency, the sensitivity (0.6) of the Orthophos XG 3D(®) equipment was superior, while specificity (0.91) was higher with the Orthopantomograph OP300(®). On the receiver operating characteristics curve, moderate performance was found with an accuracy of 0.73 (OrthopantomographOP300(®)) and 0.74 (Orthophos XG 3D(®)) respectively. As far as the location of the root fracture is concerned, moderate agreement was verified using the Kappa statistic (k = 0.56). Although the regular CBCTs represent the imaging examination of choice for assisting root fracture diagnosis in endodontically treated teeth, their performance in this study demonstrated an imprecise diagnosis of fractures in a good many cases, irrespective of the tomography machine used. An early and precise detection of root fractures is of the utmost clinical importance, but the radiopaque and/or metallic filling materials in the CBCT viewing field may generate artifacts, known as the beam-hardening effect, which could compromise root fracture detection.

  2. Use of cone-beam CT and live 3-D needle guidance to facilitate percutaneous nephrostomy and nephrolithotripsy access in children and adolescents

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, C.M. [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States); Kukreja, Kamlesh [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Singewald, Timothy; Johnson, Neil D.; Racadio, John M. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Minevich, Eugene; Reddy, Pramod [Cincinnati Children' s Hospital Medical Center, Department of Urology, Cincinnati, OH (United States)

    2016-04-15

    Gaining access into non-dilated renal collecting systems for percutaneous nephrolithotripsy, particularly in patients with prohibitive body habitus and/or scoliosis, is often challenging using conventional techniques. To evaluate the feasibility of cone-beam CT for percutaneous nephrostomy placement for subsequent percutaneous nephrolithotripsy in children and adolescents. A retrospective review of percutaneous nephrostomy revealed use of cone-beam CT and 3-D guidance in 12 percutaneous nephrostomy procedures for 9 patients between 2006 and 2015. All cone-beam CT-guided percutaneous nephrostomies were for pre-lithotripsy access and all 12 were placed in non-dilated collecting systems. Technical success was 100%. There were no complications. Cone-beam CT with 3-D guidance is a technically feasible technique for percutaneous nephrostomy in children and adolescents, specifically for nephrolithotripsy access in non-dilated collecting systems. (orig.)

  3. Upper airway alterations/abnormalities in a case series of obstructive sleep apnea patients identified with cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Shigeta, Y.; Shintaku, W.H.; Clark, G.T. [Orofacial Pain/Oral Medicine Center, Div. of Diagnostic Sciences, School of Dentistry, Univ. of Southern California, Los Angeles, CA (United States); Enciso, R. [Div. of Craniofacial Sciences and Therapeutics, School of Dentistry, Univ. of Southern California, Los Angeles, CA (United States); Ogawa, T. [Dept. of Fixed Prosthodontic Dentistry, Tsurumi Univ., School of Dental Medicine, Tsurumi (Japan)

    2007-06-15

    There are many factors that influence the configuration of the upper airway and may contribute to the development of obstructive sleep apnea (OSA). This paper presents a series of 12 consecutive OSA cases where various upper airway alteration/abnormalities were identified using 3D anatomic reconstructions generated from cone-beam CT (CBCT) images. Some cases exhibited more than one type of abnormality and below we describe each of the six types identified with CBCT in this case series. (orig.)

  4. Using corrected Cone-Beam CT image for accelerated partial breast irradiation treatment dose verification: the preliminary experience

    OpenAIRE

    Wang, Jiazhou; Hu, Weigang; Cai, Gang; Peng, Jiayuan; Pan, Ziqiang; Guo, Xiaomao; Chen, Jiayi

    2013-01-01

    Background Accurate target localization is mandatory in the accelerated partial breast irradiation (APBI) delivery. Dosimetric verification for positional error will further guarantee the accuracy of treatment delivery. The purpose of this study is to evaluate the clinical feasibility of a cone beam computer tomographic (CBCT) image correction method in APBI. Methods A CBCT image correction method was developed. First, rigid image registration was proceeded for CTs and CBCTs; second, these im...

  5. Use of Reference Ear Plug to improve accuracy of lateral cephalograms generated from cone-beam computed tomography scans

    OpenAIRE

    Hwang, Hyeon-Shik; Lee, Kyung-Min; Uhm, Gi-Soo; Cho, Jin-Hyoung; McNamara, James A.

    2013-01-01

    Objective The purpose of this study was to evaluate the effectiveness of the use of Reference Ear Plug (REP) during cone-beam computed tomography (CBCT) scan for the generation of lateral cephalograms from CBCT scan data. Methods Two CBCT scans were obtained from 33 adults. One CBCT scan was acquired using conventional methods, and the other scan was acquired with the use of REP. Virtual lateral cephalograms created from each CBCT image were traced and compared with tracings of the real cepha...

  6. Accuracy of Cone Beam Computed Tomography in Diagnosis and Treatment Planning of Periodontal Bone Defects: A Case Report

    OpenAIRE

    Songa, Vajra Madhuri; Jampani, Narendra Dev; Babu, Venkateshwara; Buggapati, Lahari; Mittapally, Sowjanya

    2014-01-01

    Diagnosis of periodontitis depend mostly on traditional two-dimensional (2-D) radiographic assessment. Regardless of efforts in improving reliability, present methods of detecting bone level changes over time or determining three-dimensional (3-D) architecture of osseous defects are lacking. To improve the diagnostic potential, an imaging modality which would give an undistorted 3-D vision of a tooth and surrounding structures is imperative. Cone beam computed tomography (CBCT) generates 3D v...

  7. Theoretical aspects of implementation of kilovoltage cone-beam CT onboard linear accelerator for image-guided radiotherapy.

    Science.gov (United States)

    Rodríguez Cordón, Marta; Ferrer Albiach, Carlos

    2009-08-01

    The main objective of image-guided radiation therapy (IGRT) equipment is to reduce and correct inherent errors in external radiotherapy processes. At the present time, there are different IGRT systems available, but here we will refer exclusively to the kilovoltage cone-beam CT onboard linear accelerator (CBkVCT) and the different aspects that, from a clinical point of view, should be taken into consideration before the implementation of this equipment.

  8. Cone beam computed tomography findings of ectopic mandibular third molar in the mandibular condyle: report of a case

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Soo [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2011-09-15

    Impaction of third molar is a common developmental abnormality. However, ectopic impaction of the mandibular third molar in condylar region is an extremely rare condition. This report describes a case of impacted tooth in the mandibular condyle without any associated pathologic condition. Also, this report presents the spatial relationship of the impacted mandibular third molar to the surrounding anatomic structures using cone beam computed tomography.

  9. Maxillary First Molars with Six Canals Diagnosed with the Aid of Cone Beam Computed Tomography: A Report of Two Cases

    Directory of Open Access Journals (Sweden)

    Mamta Kaushik

    2013-01-01

    Full Text Available The case reports present the endodontic management of two maxillary first molars with six canals. The diagnosis of morphology of multiple canal systems was identified under magnification of the dental operating microscope and was confirmed with the help of cone beam computed tomography. This paper discusses the variations in the canal morphology and the use of the latest adjuncts in successfully diagnosing and treating unusual canal anatomy.

  10. Identification and Endodontic Management of Middle Mesial Canal in Mandibular Second Molar Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Bonny Paul

    2015-01-01

    Full Text Available Endodontic treatments are routinely done with the help of radiographs. However, radiographs represent only a two-dimensional image of an object. Failure to identify aberrant anatomy can lead to endodontic failure. This case report presents the use of three-dimensional imaging with cone beam computed tomography (CBCT as an adjunct to digital radiography in identification and management of mandibular second molar with three mesial canals.

  11. Tomografía computada cone beam en articulación témporo mandibular (ATM

    Directory of Open Access Journals (Sweden)

    DR. B. Andrés Briner

    2014-09-01

    El propósito del presente artículo es exponer imágenes de alta resolución obtenidas mediante la técnica de Cone Beam, mostrando la elevada capacidad que esta técnica tiene para detectar cambios óseos morfológicos sutiles, que permiten el diagnóstico de las diversas etapas del proceso óseo degenerativo.

  12. Reduction of Cone-Beam CT scan time without compromising the accuracy of the image registration in IGRT

    DEFF Research Database (Denmark)

    Westberg, Jonas; Jensen, Henrik R; Bertelsen, Anders;

    2010-01-01

    In modern radiotherapy accelerators are equipped with 3D cone-beam CT (CBCT) which is used to verify patient position before treatment. The verification is based on an image registration between the CBCT acquired just before treatment and the CT scan made for the treatment planning. The purpose...... of this study is to minimise the scan time of the CBCT without compromising the accuracy of the image registration in IGRT....

  13. Impact of cone-beam computed tomography on implant planning and on prediction of implant size

    Energy Technology Data Exchange (ETDEWEB)

    Pedroso, Ludmila Assuncao de Mello; Silva, Maria Alves Garcia Santos, E-mail: ludmilapedroso@hotmail.com [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia; Garcia, Robson Rodrigues [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Medicina Oral; Leles, Jose Luiz Rodrigues [Universidade Paulista (UNIP), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Cirurgia; Leles, Claudio Rodrigues [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Prevencao e Reabilitacao Oral

    2013-11-15

    The aim was to investigate the impact of cone-beam computed tomography (CBCT) on implant planning and on prediction of final implant size. Consecutive patients referred for implant treatment were submitted to clinical examination, panoramic (PAN) radiography and a CBCT exam. Initial planning of implant length and width was assessed based on clinical and PAN exams, and final planning, on CBCT exam to complement diagnosis. The actual dimensions of the implants placed during surgery were compared with those obtained during initial and final planning, using the McNemmar test (p < 0.05). The final sample comprised 95 implants in 27 patients, distributed over the maxilla and mandible. Agreement in implant length was 50.5% between initial and final planning, and correct prediction of the actual implant length was 40.0% and 69.5%, using PAN and CBCT exams, respectively. Agreement in implant width assessment ranged from 69.5% to 73.7%. A paired comparison of the frequency of changes between initial or final planning and implant placement (McNemmar test) showed greater frequency of changes in initial planning for implant length (p < 0.001), but not for implant width (p = 0.850). The frequency of changes was not influenced by implant location at any stage of implant planning (chi-square test, p > 0.05). It was concluded that CBCT improves the ability of predicting the actual implant length and reduces inaccuracy in surgical dental implant planning. (author)

  14. Condylar asymmetry in children with juvenile idiopathic arthritis assessed by cone-beam computed tomography.

    Science.gov (United States)

    Huntjens, Elisabeth; Kiss, Gabriel; Wouters, Carine; Carels, Carine

    2008-12-01

    The purpose of this study was to determine the degree of condylar asymmetry in children with juvenile idiopathic arthritis (JIA) using cone-beam computed tomography (CBCT) and analysis software. For 20 patients (14 girls and six boys; mean age 11.21 +/- 3.54 years), resultant cross-sectional images of the left and right temporomandibular joints (TMJs) were semi-automatically segmented, and exact registration of the right, with respect to the flipped left grey-level condyle, was obtained. Visual inspection of the volume images in 360 degree rotation showed a wide variety of condylar destruction patterns, ranging from small erosions within the cortex to almost complete deformation of the condylar head. Because segmentation was restricted to the delineation of the cortical region, possible changes in the deeper zones were not reproduced. Descriptive statistics [median and interquartile range (IQR)] and diagrams (frequency distribution) were used to assess the results. Initial analysis of condylar volume (including both flipped left and right) showed a median value for volume of 0.844 cm(3) (IQR 0.323), while the median value for volume difference between both condyles was 0.051 cm(3) (IQR 0.098). Analysis of the degree of asymmetry showed a median value of 26.18 per cent (IQR 14.46). Using the CBCT-based method, it was shown that condylar asymmetry was a common feature in children with JIA. The degree of asymmetry was variable, but significant in the majority of the subjects.

  15. Prevalence of incidental maxillary sinus pathologies in dental patients on cone-beam computed tomographic images

    Directory of Open Access Journals (Sweden)

    Mamta Raghav

    2014-01-01

    Full Text Available Objectives: The aim of the present study was to infer and to record the prevalence of incidental maxillary sinus pathologies in patients presenting with dental problems using the cone-beam computed tomography (CBCT scans performed for maxillofacial diagnostic purposes. Materials and Methods: This retrospective study has evaluated 201 patients (402 maxillary sinuses consecutive CBCT for various incidental maxillary sinus pathologies by two observers. Pathologic findings were categorized as mucosal thickening (MT, opacification (OPA, polypoidal-mucosal thickening (PT, others (antrolith and discontinuity of the sinus fl oor and no pathologic findings. Correlations for pathologic findings and the factors of age and gender were calculated. Results: The prevalence for total incidental findings is 59.7%. The present study showed MT (35.1% as most prevalent finding followed by OPA in (16.6%, PT in 7.2% and others in 0.7%. There was no statistically significant difference between gender and between the age groups. There was no statistically significant difference between different indications groups for CBCT scans. Conclusions: The incidental maxillary sinus abnormalities are highly prevalent in the asymptomatic dental patients; hence oral radiologists should be aware of these incidental findings and comprehensively evaluate the entire captured CBCT volume, which can help in early diagnosis, treatment and follow-up of the patient.

  16. Ultrafast cone-beam computed tomography imaging and postprocessing data during image-guided therapeutic practice

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jijo; Vogl, Thomas J. [University Hospital Frankfurt, Diagnostic and Interventional Radiology, Frankfurt/Main (Germany); Mbalisike, Emmanuel C. [Hospital of the Bad Salzungen GmbH, Diagnostic and Interventional Radiology, Bad Salzungen (Germany)

    2014-11-15

    Our objective was to evaluate ultrafast cone-beam computed tomography (u-CBCT) image data using cross-sectional images, perfusion blood volume (PBV), and image fusion during tumour detection at the course of transarterial chemoembolization. One hundred and fifty patients (63 ± 20 years; 33-82) were examined from February to October 2013 with u-CBCT. Tumour delineation and conspicuity were determined using u-CBCT cross-sectional PBV and u-CBCT-magnetic resonance imaging (MRI) fused data sets for hyperenhanced (HYET), heterogeneously enhanced (HEET), and unenhanced (UET) tumour categories. Catheter localisation and tumour feeding vessels were assessed using all data sets. Quantitative and qualitative analyses were performed using appropriate statistical tests. Qualitative and quantitative tumour delineation showed significant difference (all P < 0.05) among tumour categories. Mean tumour-liver-contrast was higher in HYET than in HEET, and UET; moreover, differences between tumour categories were statistically significant (all P < 0.0001). Fused data showed higher value with statistical significance (P < 0.05) compared with other data sets during catheter localisation and feeding-vessel identification. Tumour delineation was clearly possible using u-CBCT cross sections with contrast material. PBV uses color-coded images to increase detection and produces good tumour differentiation. Image fusion helps accurately identify tumour and feeding vessels and locate contrast material injection sites and catheter tips without additional data acquisition. (orig.)

  17. Detectability of hepatic tumors during 3D post-processed ultrafast cone-beam computed tomography

    Science.gov (United States)

    Paul, Jijo; Vogl, Thomas J.; Chacko, Annamma

    2015-10-01

    To evaluate hepatic tumor detection using ultrafast cone-beam computed tomography (UCBCT) cross-sectional and 3D post-processed image datasets. 657 patients were examined using UCBCT during hepatic transarterial chemoembolization (TACE), and data were collected retrospectively from January 2012 to September 2014. Tumor detectability, diagnostic ability, detection accuracy and sensitivity were examined for different hepatic tumors using UCBCT cross-sectional, perfusion blood volume (PBV) and UCBCT-MRI (magnetic resonance imaging) fused image datasets. Appropriate statistical tests were used to compare collected sample data. Fused image data showed the significantly higher (all P  color display. Fused image data produced 100% tumor sensitivity due to the simultaneous availability of MRI and UCBCT information during tumor diagnosis. Fused image data produced excellent hepatic tumor sensitivity, detectability and diagnostic ability compared to other datasets assessed. Fused image data is extremely reliable and useful compared to UCBCT cross-sectional or PBV image datasets to depict hepatic tumors during TACE. Partial anatomical visualization on cross-sectional images was compensated by fused image data during tumor diagnosis.

  18. Determination of size-specific exposure settings in dental cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Pauwels, Ruben [Chulalongkorn University, Department of Radiology, Faculty of Dentistry, Patumwan, Bangkok (Thailand); University of Leuven, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Jacobs, Reinhilde [University of Leuven, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Bogaerts, Ria [University of Leuven, Laboratory of Experimental Radiotherapy, Department of Oncology, Biomedical Sciences Group, Leuven (Belgium); Bosmans, Hilde [University of Leuven, Medical Physics and Quality Assessment, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Panmekiate, Soontra [Chulalongkorn University, Department of Radiology, Faculty of Dentistry, Patumwan, Bangkok (Thailand)

    2017-01-15

    To estimate the possible reduction of tube output as a function of head size in dental cone-beam computed tomography (CBCT). A 16 cm PMMA phantom, containing a central and six peripheral columns filled with PMMA, was used to represent an average adult male head. The phantom was scanned using CBCT, with 0-6 peripheral columns having been removed in order to simulate varying head sizes. For five kV settings (70-90 kV), the mAs required to reach a predetermined image noise level was determined, and corresponding radiation doses were derived. Results were expressed as a function of head size, age, and gender, based on growth reference charts. The use of 90 kV consistently resulted in the largest relative dose reduction. A potential mAs reduction ranging from 7 % to 50 % was seen for the different simulated head sizes, showing an exponential relation between head size and mAs. An optimized exposure protocol based on head circumference or age/gender is proposed. A considerable dose reduction, through reduction of the mAs rather than the kV, is possible for small-sized patients in CBCT, including children and females. Size-specific exposure protocols should be clinically implemented. (orig.)

  19. An experimental cone-beam micro-CT system for small animal imaging

    Science.gov (United States)

    Zhu, Shouping; Tian, Jie; Yan, Guorui; Qin, Chenghu; Liu, Junting

    2009-02-01

    An experimental cone-beam Micro-CT system for small animal imaging is presented in the paper. The system is designed to obtain high-resolution anatomic information and will be integrated with our bioluminescence tomography system. A flat panel X-ray detector (CMOS technology with a column CsI scintillator plate, 50 micron pixel size, 120 mm × 120 mm photodiode area) and a micro-focus X-ray source (13 to 40 μm of focal spot size) are used in the system. The object (mouse or rat) is placed on a three-degree (two translations and one rotation) programming stage and could be located to an accurate position in front of the detector. The large field of view (FOV) of the system allows us to acquire the whole body imaging of a normal mouse in one scanning which usually takes about 6 to 15 minutes. Raw data from X-ray detector show spatial variation caused by dark image offset, pixel gain and defective pixels, therefore data pre-processing is needed before reconstruction. Geometry calibrations are also used to reduce the artifacts caused by geometric misalignment. In order to accelerate FDK filtered backprojection method, we develop a reconstruction software using GPU hardware in our system. System spacial resolution and image uniformity and voxel noise have been assessed and mouse reconstruction images are illuminated in the paper. Experiment results show that this system is suitable for small animal imaging.

  20. Scatter correction for cone-beam computed tomography using self-adaptive scatter kernel superposition

    Institute of Scientific and Technical Information of China (English)

    XIE Shi-Peng; LUO Li-Min

    2012-01-01

    The authors propose a combined scatter reduction and correction method to improve image quality in cone beam computed tomography (CBCT).The scatter kernel superposition (SKS) method has been used occasionally in previous studies.However,this method differs in that a scatter detecting blocker (SDB) was used between the X-ray source and the tested object to model the self-adaptive scatter kernel.This study first evaluates the scatter kernel parameters using the SDB,and then isolates the scatter distribution based on the SKS.The quality of image can be improved by removing the scatter distribution.The results show that the method can effectively reduce the scatter artifacts,and increase the image quality.Our approach increases the image contrast and reduces the magnitude of cupping.The accuracy of the SKS technique can be significantly improved in our method by using a self-adaptive scatter kernel.This method is computationally efficient,easy to implement,and provides scatter correction using a single scan acquisition.

  1. Fast three-dimensional superimposition of cone beam computed tomography for orthopaedics and orthognathic surgery evaluation.

    Science.gov (United States)

    Weissheimer, A; Menezes, L M; Koerich, L; Pham, J; Cevidanes, L H S

    2015-09-01

    The aim of this study was to validate a method for fast three-dimensional (3D) superimposition of cone beam computed tomography (CBCT) in growing patients and adults (surgical cases). The sample consisted of CBCT scans of 18 patients. For 10 patients, as the gold standard, the spatial position of the pretreatment CBCT was reoriented, saved as a reoriented volume, and then superimposed on the original image. For eight patients, four non-growing and four growing, the pre- and post-treatment scans were superimposed. Fast voxel-based superimposition was performed, with registration at the anterior cranial base. This superimposition process took 10-15s. The fit of the cranial base superimposition was verified by qualitative visualization of the semi-transparent axial, sagittal, and coronal cross-sectional slices of all corresponding anatomical structures. Virtual 3D surface models of the skull were generated via threshold segmentation, and superimposition errors in the reoriented models and the results of treatment for the treated cases were evaluated by 3D surface distances on colour-coded maps. The superimposition error of the spatial reorientation and for growing and non-growing patients was <0.5mm, which is acceptable and clinically insignificant. The voxel-based superimposition method evaluated was reproducible in different clinical conditions, rapid, and applicable for research and clinical practice. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  2. Versatility of the cone beam computed tomography in oral surgery: an overview

    Directory of Open Access Journals (Sweden)

    Kishan G. Panicker

    2011-11-01

    Full Text Available Cone beam CT (CBCT produces threedimensional information on the facial skeleton, teeth and their surrounding tissues; and is increasingly being used in many of the dental specialties. This is usually achieved with a substantially lower effective dose compared with conventional medical computed tomography (CT. Periapical pathologies, root fractures, root canal anatomy and the true nature of the alveolar bone topography around teeth may be assessed. CBCT scans are desirable to assess posterior teeth prior to periapical surgery, as the thickness of the cortical and cancellous bone can be accurately determined as can the inclination of roots in relation to the surrounding jaw. The relationship of anatomical structures such as the maxillary sinus and inferior dental nerve to the root apices may also be clearly visualized. Measurements on CBCT are more accurate when compared with OPG. Therefore, CBCT permits the clinician to have all necessary information when planning dental implants. The purpose of this article is to provide an overview of the unique image display capabilities of maxillofacial CBCT systems and to illustrate specific applications in clinical practice.

  3. Management of Oehler’s Type III Dens Invaginatus Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Jaya Ranganathan

    2016-01-01

    Full Text Available Dens Invaginatus is a dental malformation that poses diagnostic difficulties in the clinical context. This anomaly may increase the risk of pulp disease and can potentially complicate endodontic procedure due to the aberrant root canal anatomy. Compared to conventional radiographs, three-dimensional images obtained with Cone Beam Computed Tomography (CBCT are invaluable in the diagnosis of the extent of this anomaly and in the appropriate treatment planning. Oehler’s classification (1957 for Dens Invaginatus (DI into three types depending on the depth of the invagination has been used for treatment planning. Of the three types Type III DI is characterized by infolding of the enamel into the tooth up to the root apex and is considered as the most severe variant of DI and hence the most challenging to treat endodontically, due to the morphological complexities. This report describes a case of Oehler’s Type III DI in a necrotic permanent maxillary lateral incisor in which CBCT images played a key role in diagnosis and treatment planning. The case was managed successfully by a combination of nonsurgical and surgical endodontic therapy with orthograde and retrograde thermoplastic gutta percha obturation.

  4. Assessment of the relationship between the maxillary molars and adjacent structures using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2012-09-15

    This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.

  5. Accuracy and precision of cone beam computed tomography in periodontal defects measurement (systematic review

    Directory of Open Access Journals (Sweden)

    Enas Anter

    2016-01-01

    Full Text Available Systematic review of literature was made to assess the extent of accuracy of cone beam computed tomography (CBCT as a tool for measurement of alveolar bone loss in periodontal defect. A systematic search of PubMed electronic database and a hand search of open access journals (from 2000 to 2015 yielded abstracts that were potentially relevant. The original articles were then retrieved and their references were hand searched for possible missing articles. Only articles that met the selection criteria were included and criticized. The initial screening revealed 47 potentially relevant articles, of which only 14 have met the selection criteria; their CBCT average measurements error ranged from 0.19 mm to 1.27 mm; however, no valid meta-analysis could be made due to the high heterogeneity between the included studies. Under the limitation of the number and strength of the available studies, we concluded that CBCT provides an assessment of alveolar bone loss in periodontal defect with a minimum reported mean measurements error of 0.19 ± 0.11 mm and a maximum reported mean measurements error of 1.27 ± 1.43 mm, and there is no agreement between the studies regarding the direction of the deviation whether over or underestimation. However, we should emphasize that the evidence to this data is not strong.

  6. Pseudo super-resolution for improved calcification characterization for cone beam breast CT (CBBCT)

    Science.gov (United States)

    Liu, Jiangkun; Ning, Ruola; Cai, Weixing

    2010-04-01

    Cone Beam Breast CT imaging (CBBCT) is a promising tool for diagnosis of breast tumors and calcifications. However, as the sizes of calcifications in early stages are very small, it is not easy to distinguish them from background tissues because of the relatively high noise level. Therefore, it is necessary to enhance the visualization of calcifications for accurate detection. In this work, the Papoulis-Gerchberg (PG) method was introduced and modified to improve calcification characterization. PG method is an iterative algorithm of signal extrapolation and has been demonstrated to be very effective in image restoration like super-resolution (SR) and inpainting. The projection images were zoomed by bicubic interpolation method, then the modified PG method were applied to improve the image quality. The reconstruction from processed projection images showed that this approach can effectively improve the image quality by improving the Modulation Transfer Function (MTF) with a limited increase in noise level. As a result, the detectability of calcifications was improved in CBBCT images.

  7. Detection performance study for cone-beam differential phase contrast CT

    Science.gov (United States)

    Li, Ke; Bevins, Nicholas; Zambelli, Joseph; Qi, Zhihua; Chen, Guang-Hong

    2012-03-01

    X-ray phase sensitive imaging methods have seen tremendous growth and increased interest in recent years. Each method has its advantages and disadvantages, but all have shown the ability to improve the detection of various objects because of the additional phase measurements. Of the various methods, grating-based differential phase contrast computed tomography (DPC-CT) imaging has shown greater quantitative and diagnostic capabilities than traditional absorption CT. Although it has been shown that DPC-CT provides superior contrast of certain materials, one question has not been fully addressed to date is whether DPC-CT can provide improved accuracy in detecting low contrast masses using the same radiation dose as that given in absorption CT. The detectability is not only related to contrast to noise ratio, but also to the noise texture. The purpose of this study is to investigate how the peculiar noise texture found in cone-beam DPC-CT affects low contrast objects' detectability through human observer ROC analysis. Studies for both axial and sagittal planes were carried out, as both could potentially be used in clinical practice for a 3D image. The results demonstrate that noise texture found in conebeam DPC-CT strongly affects human visual perception, and that object detectabilities in axial and sagittal images of DPC-CT are different.

  8. Automatic Calibration Method of Voxel Size for Cone-beam 3D-CT Scanning System

    CERN Document Server

    Yang, Min; Liu, Yipeng; Men, Fanyong; Li, Xingdong; Liu, Wenli; Wei, Dongbo

    2013-01-01

    For cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary table along X-ray direction. In order to realize the automatic calibration of the voxel size, a new easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least square fitting. Through these interpolation values, a linear equation is obtained, which reflects the relationship between the rotary table displacement distance from its nominal zero position and the voxel size. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system, and when the rotary table is moving along X-ray direction, the accurate value of the voxel size is dynamically expo...

  9. Occurrence of maxillary sinus abnormalities detected by cone beam CT in asymptomatic patients

    Directory of Open Access Journals (Sweden)

    Rege Inara Carneiro

    2012-08-01

    Full Text Available Abstract Background Although cone beam computed tomography (CBCT images of the maxillofacial region allow the inspection of the entire volume of the maxillary sinus (MS, identifying anatomic variations and abnormalities in the image volume, this is frequently neglected by oral radiologists when interpreting images of areas at a distance from the dentoalveolar region, such as the full anatomical aspect of the MS. The aim of this study was to investigate maxillary sinus abnormalities in asymptomatic patients by using CBCT. Methods 1113 CBCT were evaluated by two examiners and identification of abnormalities, the presence of periapical lesions and proximity to the lower sinus wall were recorded. Data were analyzed using descriptive statistics, chi-square tests and Kappa statistics. Results Abnormalities were diagnosed in 68.2% of cases (kappa = 0.83. There was a significant difference between genders (p Conclusions Abnormalities in maxillary sinus emphasizes how important it is for the dentomaxillofacial radiologist to undertake an interpretation of the whole volume of CBCT images.

  10. Imaging characteristics of distance-driven method in a prototype cone-beam computed tomography (CBCT)

    Science.gov (United States)

    Choi, Sunghoon; Kim, Ye-seul; Lee, Haenghwa; Lee, Donghoon; Seo, Chang-Woo; Kim, Hee-Joung

    2016-03-01

    Cone-beam computed tomography (CBCT) has widely been used and studied in both medical imaging and radiation therapy. The aim of this study was to evaluate our newly developed CBCT system by implementing a distance-driven system modeling technique in order to produce excellent and accurate cross-sectional images. For the purpose of comparing the performance of the distance-driven methods, we also performed pixel-driven and ray-driven techniques when conducting forward- and back-projection schemes. We conducted the Feldkamp-Davis-Kress (FDK) algorithm and simultaneous algebraic reconstruction technique (SART) to retrieve a volumetric information of scanned chest phantom. The results indicated that contrast-to-noise (CNR) of the reconstructed images by using FDK and SART showed 8.02 and 15.78 for distance-driven, whereas 4.02 and 5.16 for pixel-driven scheme and 7.81 and 13.01 for ray-driven scheme, respectively. This could demonstrate that distance-driven method described more closely the chest phantom compared to pixel- and ray-driven. However, both elapsed time for modeling a system matrix and reconstruction time took longer time when performing the distance-driven scheme. Therefore, future works will be directed toward reducing computational time to acceptable limits for real applications.

  11. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Directory of Open Access Journals (Sweden)

    João Paulo SCHWARTZ

    2015-10-01

    Full Text Available Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT.Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0 and after Herbst treatment (T1. All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%.Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders.Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance.

  12. View-dependent geometric calibration for offset flat-panel cone beam computed tomography systems

    Science.gov (United States)

    Nguyen, Van-Giang

    2016-04-01

    Geometric parameters that define the geometry of imaging systems are crucial for image reconstruction and image quality in x-ray computed tomography (CT). The problem of determining geometric parameters for an offset flat-panel cone beam CT (CBCT) system, a recently introduced modality with a large field of view, with the assumption of an unstable mechanism and geometric parameters that vary in each view, is considered. To accurately and rapidly find the geometric parameters for each projection view, we use the projection matrix method and design a dedicated phantom that is partially visible in all projection views. The phantom consists of balls distributed symmetrically in a cylinder to ensure the inclusion of the phantom in all views, and a large portion of the phantom is covered in the projection image. To efficiently use calibrated geometric information in the reconstruction process and get rid of approximation errors, instead of decomposing the projection matrix into actual geometric parameters that are manually corrected before being used in reconstruction, as in conventional methods, we directly use the projection matrix and its pseudo-inverse in projection and backprojection operations of reconstruction algorithms. The experiments illustrate the efficacy of the proposed method with a real offset flat-panel CBCT system in dental imaging.

  13. Robust scatter correction method for cone-beam CT using an interlacing-slit plate

    Science.gov (United States)

    Huang, Kui-Dong; Xu, Zhe; Zhang, Ding-Hua; Zhang, Hua; Shi, Wen-Long

    2016-06-01

    Cone-beam computed tomography (CBCT) has been widely used in medical imaging and industrial nondestructive testing, but the presence of scattered radiation will cause significant reduction of image quality. In this article, a robust scatter correction method for CBCT using an interlacing-slit plate (ISP) is carried out for convenient practice. Firstly, a Gaussian filtering method is proposed to compensate the missing data of the inner scatter image, and simultaneously avoid too-large values of calculated inner scatter and smooth the inner scatter field. Secondly, an interlacing-slit scan without detector gain correction is carried out to enhance the practicality and convenience of the scatter correction method. Finally, a denoising step for scatter-corrected projection images is added in the process flow to control the noise amplification The experimental results show that the improved method can not only make the scatter correction more robust and convenient, but also achieve a good quality of scatter-corrected slice images. Supported by National Science and Technology Major Project of the Ministry of Industry and Information Technology of China (2012ZX04007021), Aeronautical Science Fund of China (2014ZE53059), and Fundamental Research Funds for Central Universities of China (3102014KYJD022)

  14. Automated patient setup and gating using cone beam computed tomography projections

    Science.gov (United States)

    Wan, Hanlin; Bertholet, Jenny; Ge, Jiajia; Poulsen, Per; Parikh, Parag

    2016-03-01

    In radiation therapy, fiducial markers are often implanted near tumors and used for patient positioning and respiratory gating purposes. These markers are then used to manually align the patients by matching the markers in the cone beam computed tomography (CBCT) reconstruction to those in the planning CT. This step is time-intensive and user-dependent, and often results in a suboptimal patient setup. We propose a fully automated, robust method based on dynamic programming (DP) for segmenting radiopaque fiducial markers in CBCT projection images, which are then used to automatically optimize the treatment couch position and/or gating window bounds. The mean of the absolute 2D segmentation error of our DP algorithm is 1.3+/- 1.0 mm for 87 markers on 39 patients. Intrafraction images were acquired every 3 s during treatment at two different institutions. For gated patients from Institution A (8 patients, 40 fractions), the DP algorithm increased the delivery accuracy (96+/- 6% versus 91+/- 11% , p  CBCT to the mean position. Our proposed automated patient setup algorithm only takes 1-2 s to run, requires no user intervention, and performs as well as or better than the current clinical setup.

  15. CT to Cone-beam CT Deformable Registration With Simultaneous Intensity Correction

    CERN Document Server

    Zhen, Xin; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B

    2012-01-01

    Computed tomography (CT) to cone-beam computed tomography (CBCT) deformable image registration (DIR) is a crucial step in adaptive radiation therapy. Current intensity-based registration algorithms, such as demons, may fail in the context of CT-CBCT DIR because of inconsistent intensities between the two modalities. In this paper, we propose a variant of demons, called Deformation with Intensity Simultaneously Corrected (DISC), to deal with CT-CBCT DIR. DISC distinguishes itself from the original demons algorithm by performing an adaptive intensity correction step on the CBCT image at every iteration step of the demons registration. Specifically, the intensity correction of a voxel in CBCT is achieved by matching the first and the second moments of the voxel intensities inside a patch around the voxel with those on the CT image. It is expected that such a strategy can remove artifacts in the CBCT image, as well as ensuring the intensity consistency between the two modalities. DISC is implemented on computer g...

  16. A GPU Tool for Efficient, Accurate, and Realistic Simulation of Cone Beam CT Projections

    CERN Document Server

    Jia, Xun; Cervino, Laura; Folkerts, Michael; Jiang, Steve B

    2012-01-01

    Simulation of x-ray projection images plays an important role in cone beam CT (CBCT) related research projects. A projection image contains primary signal, scatter signal, and noise. It is computationally demanding to perform accurate and realistic computations for all of these components. In this work, we develop a package on GPU, called gDRR, for the accurate and efficient computations of x-ray projection images in CBCT under clinically realistic conditions. The primary signal is computed by a tri-linear ray-tracing algorithm. A Monte Carlo (MC) simulation is then performed, yielding the primary signal and the scatter signal, both with noise. A denoising process is applied to obtain a smooth scatter signal. The noise component is then obtained by combining the difference between the MC primary and the ray-tracing primary signals, and the difference between the MC simulated scatter and the denoised scatter signals. Finally, a calibration step converts the calculated noise signal into a realistic one by scali...

  17. GPU-based Iterative Cone Beam CT Reconstruction Using Tight Frame Regularization

    CERN Document Server

    Jia, Xun; Lou, Yifei; Jiang, Steve B

    2010-01-01

    X-ray imaging dose from serial cone-beam CT (CBCT) scans raises a clinical concern in most image guided radiation therapy procedures. It is the goal of this paper to develop a fast GPU-based algorithm to reconstruct high quality CBCT images from undersampled and noisy projection data so as to lower the imaging dose. For this purpose, we have developed an iterative tight frame (TF) based CBCT reconstruction algorithm. A condition that a real CBCT image has a sparse representation under a TF basis is imposed in the iteration process as regularization to the solution. To speed up the computation, a multi-grid method is employed. Our GPU implementation has achieved high computational efficiency and a CBCT image of resolution 512x512x70 can be reconstructed in about ~139 sec. We have tested our algorithm on a digital NCAT phantom and a physical Catphan phantom. It is found that our TF-based algorithm leads to much higher CBCT quality than those obtained from a conventional FDK algorithm in the context of undersamp...

  18. GPU-based Cone Beam CT Reconstruction via Total Variation Regularization

    CERN Document Server

    Jia, Xun; Lewis, John; Li, Ruijiang; Gu, Xuejun; Men, Chunhua; Jiang, Steve B

    2010-01-01

    Cone-beam CT (CBCT) reconstruction is of central importance in image guided radiation therapy due to its broad applications in many clinical contexts. However, the high image dose in CBCT scans is a clinical concern, especially when it is used repeatedly for patient setup purposes before each radiotherapy treatment fraction. A desire for lower imaging does has motivated a vast amount of interest in the CBCT reconstruction based on a small number of X-ray projections. Recently, advances in image processing and compressed sensing have led to tremendous success in recovering signals based on extremely low sampling rates, laying the mathematical foundation for reconstructing CBCT from few projections. In this paper, we present our recent development on a GPU-based iterative algorithm for the highly under-sampled CBCT reconstruction problem. We considered an energy functional consisting of a data fidelity term and a regularization term of a total variation norm. In order to solve our model, we developed a modified...

  19. Evaluation of accuracy of cone beam computed tomography for measurement of periodontal defects: A clinical study

    Directory of Open Access Journals (Sweden)

    Akshaya Bhupesh Banodkar

    2015-01-01

    Full Text Available Aims: The aim of the present study was to evaluate the accuracy of Cone Beam Computed Tomography (CBCT measurements of alveolar bone defects caused due to periodontal disease, by comparing it with actual surgical measurements which is the gold standard. Methods and Material: Hundred periodontal bone defects in fifteen patients suffering from periodontitis and scheduled for flap surgery were included in the study. On the day of surgery prior to anesthesia, CBCT of the quadrant to be operated was taken. After reflection of the flap, clinical measurements of periodontal defect were made using a reamer and digital vernier caliper. The measurements taken during surgery were then compared to the measurements done with CBCT and subjected to statistical analysis using the Pearson′s correlation test. Results: Overall there was a very high correlation of 0.988 between the surgical and CBCT measurements. In case of type of defects the correlation was higher in horizontal defects as compared to vertical defects. Conclusions: CBCT is highly accurate in measurement of periodontal defects and proves to be a very useful tool in periodontal diagnosis and treatment assessment.

  20. Comparison between cone-beam and multislice computed tomography for identification of simulated bone lesions

    Energy Technology Data Exchange (ETDEWEB)

    Gaia, Bruno Felipe [University of Sao Paulo (USP), SP (Brazil). Dental School. Stomatology Dept.; Sales, Marcelo Augusto Oliveira de [University of Paraiba (UFPB), Joao Pessoa, PB (Brazil). Dental School. Dept. of Radiology; Perrella, Andreia; Fenyo-Pereira, Marlene; Cavalcanti, Marcelo Gusmao Paraiso, E-mail: mgpcaval@usp.b [University of Sao Paulo (USP), SP (Brazil). Dental School. Dept. of Radiology

    2011-07-15

    There are many studies that compare the accuracy of multislice (MSCT) and cone beam (CBCT) computed tomography for evaluations in the maxillofacial region. However, further studies comparing both acquisition techniques for the evaluation of simulated mandibular bone lesions are needed. The aim of this study was to compare the accuracy of MSCT and CBCT in the diagnosis of simulated mandibular bone lesions by means of cross sectional images and axial/MPR slices. Lesions with different dimensions, shape and locularity were produced in 15 dry mandibles. The images were obtained following the cross sectional and axial/MPR (Multiplanar Reconstruction) imaging protocols and were interpreted independently. CBCT and MSCT showed similar results in depicting the percentage of cortical bone involvement, with great sensitivity and specificity (p < 0.005). There were no significant intra- or inter-examiner differences between axial/MPR images and cross sectional images with regard to sensitivity and specificity. CBCT showed results similar to those of MSCT for the identification of the number of simulated bone lesions. Cross sectional slices and axial/MPR images presented high accuracy, proving useful for bone lesion diagnosis. (author)

  1. Digital orthodontic radiographic set versus cone-beam computed tomography: an evaluation of the effective dose

    Directory of Open Access Journals (Sweden)

    Lillian Atsumi Simabuguro Chinem

    Full Text Available ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digital radiographic methods (panoramic, lateral cephalometric and periapical with cone-beam computed tomography (CBCT. Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA, representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany, Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany and i-CAT (Imaging Sciences International, Hatfield, PA, USA. The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990 and 47.2% (ICRP 2007 of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination.

  2. Pediatric Phantom Dosimetry of Kodak 9000 Cone-beam Computed Tomography.

    Science.gov (United States)

    Yepes, Juan F; Booe, Megan R; Sanders, Brian J; Jones, James E; Ehrlich, Ygal; Ludlow, John B; Johnson, Brandon

    2017-05-15

    The purpose of the study was to evaluate the radiation dose of the Kodak 9000 cone-beam computed tomography (CBCT) device for different anatomical areas using a pediatric phantom. Absorbed doses resulting from maxillary and mandibular region three by five cm CBCT volumes of an anthropomorphic 10-year-old child phantom were acquired using optical stimulated dosimetry. Equivalent doses were calculated for radiosensitive tissues in the head and neck area, and effective dose for maxillary and mandibular examinations were calculated following the 2007 recommendations of the International Commission on Radiological Protection (ICRP). Of the mandibular scans, the salivary glands had the highest equivalent dose (1,598 microsieverts [μSv]), followed by oral mucosa (1,263 μSv), extrathoracic airway (pharynx, larynx, and trachea; 859 μSv), and thyroid gland (578 μSv). For the maxilla, the salivary glands had the highest equivalent dose (1,847 μSv), followed closely by oral mucosa (1,673 μSv), followed by the extrathoracic airway (pharynx, larynx, and trachea; 1,011 μSv) and lens of the eye (202 μSv). Compared to previous research of the Kodak 9000, completed with the adult phantom, a child receives one to three times more radiation for mandibular scans and two to 10 times more radiation for maxillary scans.

  3. Cone beam CT dose reduction in prostate radiotherapy using Likert scale methods.

    Science.gov (United States)

    Langmack, Keith A; Newton, Louise A; Jordan, Suzanne; Smith, Ruth

    2016-01-01

    To use a Likert scale method to optimize image quality (IQ) for cone beam CT (CBCT) soft-tissue matching for image-guided radiotherapy of the prostate. 23 males with local/locally advanced prostate cancer had the CBCT IQ assessed using a 4-point Likert scale (4 = excellent, no artefacts; 3 = good, few artefacts; 2 = poor, just able to match; 1 = unsatisfactory, not able to match) at three levels of exposure. The lateral separations of the subjects were also measured. The Friedman test and Wilcoxon signed-rank tests were used to determine if the IQ was associated with the exposure level. We used the point-biserial correlation and a χ(2) test to investigate the relationship between the separation and IQ. The Friedman test showed that the IQ was related to exposure (p = 2 × 10(-7)) and the Wilcoxon signed-rank test demonstrated that the IQ decreased as exposure decreased (all p-values Likert scales are a useful tool for measuring IQ in the optimization of CBCT IQ for soft-tissue matching in radiotherapy image guidance applications.

  4. Location and classification of Canalis sinuosus for cone beam computed tomography: avoiding misdiagnosis.

    Science.gov (United States)

    Manhães Júnior, Luiz Roberto Coutinho; Villaça-Carvalho, Maria Fernanda Lima; Moraes, Mari Eli Leonelli; Lopes, Sérgio Lúcio Pereira de Castro; Silva, Milena Bortolotto Felippe; Junqueira, José Luiz Cintra

    2016-01-01

    The aim of this study was to assess the presence, location and, multiplanar distance of the canalis sinuosus (CS) between the incisive foramen and the anterior maxillary alveolar ridge using cone beam computed tomography (CBCT). Therefore, 500 CBCT maxillary images obtained from male and female patients aged 20 to 80 years were selected to assist in the dental treatment. Low-quality tomographic images were discarded. All images were captured with the i-CATTM Classic tomograph and assessed using the XoranCatTM software. The axial sections were analyzed at the incisive foramen in order to verify the CS presence in laterality and location. Furthermore, linear measurements of the nasal cavity floor, buccal cortical bone, and alveolar ridge crest were made. All the collected data were statistically analyzed. Results show a variation of the CS in relation to the classification and distance of anatomical structures, but no significant difference between the right and left sides. It should be highlighted that CBCT is necessary before invasive procedures in order to preserve important anatomical structures. In conclusion, the location of the CS varies in relation to the alveolar ridge crest and buccal cortical bone, assuming that it is going to be located by the upper lateral incisor palatine.

  5. Configuration of the inferior alveolar canal as detected by cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Umadevi P Nair

    2013-01-01

    Full Text Available Aims: The aim of this study is to evaluate the course of the inferior alveolar canal (IAC including its frequently seen variations in relation to root apices and the cortices of the mandible at fixed pre-determined anatomic reference points using cone beam volumetric computed tomography (CBVCT. Material and Methods: This retrospective study utilized CBVCT images from 44 patients to obtain quantifiable data to localize the IAC. Measurements to the IAC were made from the buccal and lingual cortical plates (BCP/LCP, inferior border of the mandible and the root apices of the mandibular posterior teeth and canine. Descriptive analysis was used to map out the course of the IAC. Results: IACs were noted to course superiorly toward the root apices from the second molar to the first premolar and closer to the buccal cortical plate anteriorly. The canal was closest to the LCP at the level of the second molar. In 32.95% of the cases, the canal was seen at the level of the canine. Conclusions: This study indicates that caution needs to be exercised during endodontic surgical procedures in the mandible even at the level of the canine. CBVCT seems to provide an optimal, low-dose, 3D imaging modality to help address the complexities in canal configuration.

  6. Direct comparison of conventional radiography and cone-beam CT in small bone and joint trauma

    Energy Technology Data Exchange (ETDEWEB)

    Smet, E. de [Antwerp University Hospital, Department of Radiology, Edegem (Belgium); Praeter, G. de [Sint-Maartenziekenhuis, Department of Radiology, Duffel (Belgium); Verstraete, K.L.A. [Ghent University Hospital, Department of Radiology, Ghent (Belgium); Wouters, K. [Antwerp University Hospital, Department of Scientific Coordination and Biostatistics, Edegem (Belgium); Beuckeleer, Luc de [GZA Sint-Augustinus, Department of Radiology, Wilrijk (Belgium); Vanhoenacker, F.M.H.M. [Antwerp University Hospital, Department of Radiology, Edegem (Belgium); Sint-Maartenziekenhuis, Department of Radiology, Duffel (Belgium); Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2015-08-15

    To compare the diagnostic value of cone-beam computed tomography (CBCT) and conventional radiography (CR) after acute small bone or joint trauma. Between March 2013 and January 2014, 231 patients with recent small bone or joint trauma underwent CR and subsequent CBCT. CR and CBCT examinations were independently assessed by two readers, blinded to the result of the other modality. The total number of fractures as well as the number of complex fractures were compared, and inter- and intraobserver agreement for CBCT was calculated. In addition, radiation doses and evaluation times for both modalities were noted and statistically compared. Fracture detection on CBCT increased by 35 % and 37 % for reader 1 and reader 2, respectively, and identification of complex fractures increased by 236 % and 185 %. Interobserver agreement for CBCT was almost perfect, as was intraobserver agreement for reader 1. The intraobserver agreement for reader 2 was substantial. Radiation doses and evaluation time were significantly higher for CBCT. CBCT detects significantly more small bone and joint fractures, in particular complex fractures, than CR. In the majority of cases, the clinical implication of the additionally detected fractures is limited, but in some patients (e.g., fracture-dislocations), the management is significantly influenced by these findings. As the radiation dose for CBCT substantially exceeds that of CR, we suggest adhering to CR as the first-line examination after small bone and joint trauma and keeping CBCT for patients with clinical-radiographic discordance or suspected complex fractures in need of further (preoperative) assessment. (orig.)

  7. Effect of anatomical backgrounds on detectability in volumetric cone beam CT images

    Science.gov (United States)

    Han, Minah; Park, Subok; Baek, Jongduk

    2016-03-01

    As anatomical noise is often a dominating factor affecting signal detection in medical imaging, we investigate the effects of anatomical backgrounds on signal detection in volumetric cone beam CT images. Signal detection performances are compared between transverse and longitudinal planes with either uniform or anatomical backgrounds. Sphere objects with diameters of 1mm, 5mm, 8mm, and 11mm are used as the signals. Three-dimensional (3D) anatomical backgrounds are generated using an anatomical noise power spectrum, 1/fβ, with β=3, equivalent to mammographic background [1]. The mean voxel value of the 3D anatomical backgrounds is used as an attenuation coefficient of the uniform background. Noisy projection data are acquired by the forward projection of the uniform and anatomical 3D backgrounds with/without sphere lesions and by the addition of quantum noise. Then, images are reconstructed by an FDK algorithm [2]. For each signal size, signal detection performances in transverse and longitudinal planes are measured by calculating the task SNR of a channelized Hotelling observer with Laguerre-Gauss channels. In the uniform background case, transverse planes yield higher task SNR values for all sphere diameters but 1mm. In the anatomical background case, longitudinal planes yield higher task SNR values for all signal diameters. The results indicate that it is beneficial to use longitudinal planes to detect spherical signals in anatomical backgrounds.

  8. Temporomandibular joint osteoarthritis: cone beam computed tomography findings, clinical features, and correlations.

    Science.gov (United States)

    Cömert Kiliç, S; Kiliç, N; Sümbüllü, M A

    2015-10-01

    The aim of this study was to determine the prevalence of and associations between clinical signs and symptoms and cone beam computed tomography (CBCT) findings of temporomandibular joint osteoarthritis (TMJ-OA). Seventy-six patients (total 117 TMJ) with osteoarthritis were included in this study. Clinical signs and symptoms and CBCT findings were reviewed retrospectively. A considerable decrease in mandibular motions and mastication efficiency, and considerable increase in joint sounds and general pain complaints were observed. The most frequent condylar bony changes were erosion (110 joints, 94.0%), followed by flattening (108 joints, 92.3%), osteophytes (93 joints, 79.5%), hypoplasia (22 joints, 18.8%), sclerosis (14 joints, 12.0%), and subchondral cyst (four joints, 3.4%). Flattening of the articular eminence and pneumatization were each observed in five joints. Forty-one patients had bilateral degeneration and 35 had unilateral degeneration. Hypermobility was detected in 47 degenerative joints. Masticatory efficiency was negatively correlated with both condylar flattening and sclerosis, and general pain complaints was positively correlated with condylar flattening. Condylar erosion, flattening, osteophytes, pain, joint sounds, reduced jaw movements, and worsened mastication were common findings in TMJ-OA in the present study. Poor correlations were found between osseous changes and clinical signs and symptoms of TMJ-OA. CBCT is a powerful diagnostic tool for the diagnosis of TMJ-OA. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  9. Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Imanimoghaddam, Mahrokh; Mahdavi, Pirooze; Bagherpour, Ali; Darijani, Mansoreh; Ebrahimnejad, Hamed [Dept. of Oral and Maxillofacial Radiology, Oral and Maxillofacial Diseases Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Madani, Azam Sadat [Dept. of Oral and Maxillofacial Radiology, Oral and Maxillofacial Diseases Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

    2016-06-15

    This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients.

  10. Signs and symptoms after temporomandibular joint washing and cannula placement assessed by cone beam computerized tomography.

    Science.gov (United States)

    Kristensen, Kasper Dahl; Stoustrup, Peter; Alstergren, Per; Küseler, Annelise; Herlin, Troels; Pedersen, Thomas Klit

    2015-08-01

    Analyses of temporomandibular joint synovial fluid using the hydroxocobalamin push-pull technique are increasingly used. However, objective complications and subjective experiences from this procedure have not been described. Firstly, this study aimed to describe discomfort and potential side-effects of this method with special emphasis on symptoms related to the arthrocentesis to be used for future patient information and Ethical Committee applications. Secondly, this study aimed to evaluate the use of cone beam computed tomography (CBCT) as control of intra-capsular cannula placement. Twenty healthy, young adult volunteers were included. Extensive objective and subjective questionnaires were completed before and 14 days after the synovial fluid sampling. With the cannula inside the joints a CBCT was done to investigate if this procedure can be used to verify intra-capsular cannula position. The subjective findings: Most subjects did experience mild pain or discomfort post-operatively. In 12 of 20 subjects symptoms had resolved after 2 days and no subjects had symptoms for more than a week. The longer lasting symptoms were mainly transient joint sounds on mandibular movement. Objective findings: 14 days after the sampling mandibular protrusion had improved 1 mm, but all other objective measures were equal compared to baseline. CBCT showed a large variation in cannula position and no conclusions could be drawn from this. The hydroxocobalamin push-pull synovial fluid sampling may cause minor, transient symptoms. CBCT does not seem to provide any clinical benefits concerning the correct cannula position in relation to the upper joint compartment and disc.

  11. Usefulness of cone beam computed tomography in temporomandibular joints with soft tissue pathology

    Science.gov (United States)

    Alkhader, M; Kuribayashi, A; Ohbayashi, N; Nakamura, S; Kurabayashi, T

    2010-01-01

    Objective The aim of the study was to evaluate the usefulness of cone beam CT (CBCT) in temporomandibular joints (TMJs) with soft tissue pathology. Methods 106 TMJs of 55 patients with temporomandibular disorder (TMD) were examined by MRI and CBCT. MR images were used for the evaluation of disc displacement, disc deformity, joint effusion and obscurity of temporal posterior attachment (TPA). CBCT images were evaluated for the presence or absence of osseous abnormalities. The χ2 test was used to analyse the association between MRI and CBCT findings. Results MRI of 106 TMJs revealed disc displacement, disc deformity, joint effusion and obscurity of the TPA in 68, 73, 28 and 27 joints, respectively. Of the 68 TMJs with disc displacement, anterior disc displacement without reduction (ADDWR) was seen most frequently (47/68). CBCT imaging found 65 TMJs were characterized by the presence of osseous abnormalities and were significantly associated with disc deformity and ADDWR (P joint effusion and obscurity of TPA and TMJ osseous abnormalities. Conclusions TMD patients with confirmed ADDWR or disc deformity on MRI are at risk of having osseous abnormalities in the TMJ and further examination with CBCT is recommended. PMID:20729183

  12. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Science.gov (United States)

    SCHWARTZ, João Paulo; RAVELI, Taísa Boamorte; ALMEIDA, Kélei Cristina de Mathias; SCHWARTZ-FILHO, Humberto Osvaldo; RAVELI, Dirceu Barnabé

    2015-01-01

    Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT). Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years) with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0) and after Herbst treatment (T1). All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%. Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders. Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance. PMID:26537718

  13. Cone beam CT evaluation of patient set-up accuracy as a QA tool

    DEFF Research Database (Denmark)

    Nielsen, Morten; Bertelsen, Anders; Westberg, Jonas;

    2009-01-01

    and methods. Eighty four cancer patients have been cone beam CT scanned at treatment sessions 1, 2, 3, 10 and 20. Translational and rotational errors are analyzed. Results and conclusions. For the first three treatment sessions the mean translational error in the AP direction is 1 mm; this indicates a small...... error in the calibration of coronal isocentric laser. The observed SD of the systematic error in each direction is 1 mm if a correction is made after the third fraction with an action limit of 4 mm. The SD of the random errors of the patient group is approximately 1 mm in each direction. The rotational...... errors have a vanishing mean and a systematic error of 0.5 1.2 degrees and a random error of 0.40.7 degrees. The uncertainties from the first three treatment sessions (disregarding rotations) lead to a margin of 4 mm from ITV to PTV for Head-and-Neck patients (all directions) and Thorax patients (AP...

  14. Implementation of sensitivity and resolution modeling for SPECT with cone-beam collimator

    Science.gov (United States)

    Krol, Andrzej; Kunniyur, Vikram R.; Lee, Wei; Gangal, Kedar R.; Coman, Ioana L.; Lipson, Edward D.; Karczewski, Deborah A.; Thomas, F. Deaver; Feiglin, David H.

    2005-04-01

    We implemented a fully-3D ordered-subsets expectation-maximization (OSEM) algorithm with attenuation compensation, distance-dependent blurring (DDB), and sensitivity modeling for SPECT performed with a cone-beam collimator (CBC). The experimentally obtained detector response to point sources across FOV was fitted to a two-dimensional Gaussian function with its width (FWHM) varying linearly with the source-to-detector distance and with very weak sensitivity dependence on the emission angle. We obtained CBC SPECT scans of a physical point-source phantom, a Defrise phantom, and a female patient, and we investigated performance of our algorithm. To correctly simulate DDB and sensitivity, a blurring kernel with a radius of up to 10 elements had to be used for a 128¥128 acquisition matrix, and volumetric ray tracing rather than line-element-based ray tracing has to be implemented. In the point-source phantom reconstruction we evaluated the uniformity of FWHM for the radial, tangential and longitudinal directions, and sensitivity vs. distance. An isotropic and stationary resolution was obtained at any location by OSEM with DDB and sensitivity modeling, only when volumetric ray tracing was used. We analyzed axial and transaxial profiles obtained for the Defrise phantom and evaluated the reconstructed breast SPECT patient images. The proposed fully-3D OSEM reconstruction algorithm with DBB and sensitivity modeling, and attenuation compensation with volumetric rays tracing is efficient and effective with significant resolution and sensitivity recovery.

  15. Cone-beam CT analysis of patients with obstructive sleep apnea compared to normal controls

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, Allison; Kalathingal Sajitha; De Rossi, Scott [Dept. of Oral Health and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta (United States); Cohen, Ruben [Park Avenue Oral and Facial Surgery, New York (United States); Loony, Stephen [Dept. of Biostatistics and Epidemiology, Augusta University Medical College of Georgia, Augusta (United States)

    2016-03-15

    To evaluate the upper airway dimensions of obstructive sleep apnea (OSA) and control subjects using a cone-beam computed tomography (CBCT) unit commonly applied in clinical practice in order to assess airway dimensions in the same fashion as that routinely employed in a clinical setting. This was a retrospective analysis utilizing existing CBCT scans to evaluate the dimensions of the upper airway in OSA and control subjects. The CBCT data of sixteen OSA and sixteen control subjects were compared. The average area, average volume, total volume, and total length of the upper airway were computed. Width and anterior-posterior (AP) measurements were obtained on the smallest axial slice. OSA subjects had a significantly smaller average airway area, average airway volume, total airway volume, and mean airway width. OSA subjects had a significantly larger airway length measurement. The mean A-P distance was not significantly different between groups. OSA subjects have a smaller upper airway compared to controls with the exception of airway length. The lack of a significant difference in the mean A-P distance may indicate that patient position during imaging (upright vs. supine) can affect this measurement. Comparison of this study with a future prospective study design will allow for validation of these results.

  16. Diagnosis and planning in apical surgery: use of cone-beam tomography

    Directory of Open Access Journals (Sweden)

    Regina Karla de Pontes Lima

    2010-10-01

    Full Text Available Introduction and objective: The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT and radiography. Moreover, its clinical applications in apical surgery are discussed. Literature review and conclusion: Unlikely CT, CBCT captures a volume of data in a single 360° rotation, providing benefits such as higher accuracy, better resolution, reduced scanning time and reduced radiation dose. In the maxillofacial region, CBCT has been mainly used in the assessment of dento-alveolar pathology and oral traumatology. CBCT provides a better diagnosis and quantitative information on periodontal bone levels than conventional radiography. It has also been used for patients requiring surgical facial reconstruction, orthognathic surgery, dental implants, and more complex tooth extractions. Besides that, it seems to be a significant tool in modern endodontic practice, presenting useful applications in apical surgery.

  17. Cone-beam local reconstruction based on a Radon inversion transformation

    Institute of Scientific and Technical Information of China (English)

    Wang Xian-Chao; Yan Bin; Li Lei; Hu Guo-En

    2012-01-01

    The local reconstruction from truncated projection data is one area of interest in image reconstruction for computed tomography (CT),which creates the possibility for dose reduction.In this paper,a filtered-backprojection (FBP)algorithm based on the Radon inversion transform is presented to deal with the three-dimensional (3D) local reconstruction in the circular geometry.The algorithm achieves the data filtering in two steps.The first step is the derivative of projections,which acts locally on the data and can thus be carried out accurately even in the presence of data truncation.The second step is the nonlocal Hilbert filtering.The numerical simulations and the real data reconstructions have been conducted to validate the new reconstruction algorithm.Compared with the approximate truncation resistant algorithm for computed tomography (ATRACT),not only it has a comparable ability to restrain truncation artifacts,but also its reconstruction efficiency is improved.It is about twice as fast as that of the ATRACT.Therefore,this work provides a simple and efficient approach for the approximate reconstruction from truncated projections in the circular cone-beam CT.

  18. The effect of cone beam CT (CBCT) on therapeutic decision-making in endodontics.

    Science.gov (United States)

    Mota de Almeida, F J; Knutsson, K; Flygare, L

    2014-01-01

    The aim was to assess to what extent cone beam CT (CBCT) used in accordance with current European Commission guidelines in a normal clinical setting has an impact on therapeutic decisions in a population referred for endodontic problems. The study includes data of consecutively examined patients collected from October 2011 to December 2012. From 2 different endodontic specialist clinics, 57 patients were referred for a CBCT examination using criteria in accordance with current European guidelines. The CBCT examinations were performed using similar equipment and standardized among clinics. After a thorough clinical examination, but before CBCT, the examiner made a preliminary therapy plan which was recorded. After the CBCT examination, the same examiner made a new therapy plan. Therapy plans both before and after the CBCT examination were plotted for 53 patients and 81 teeth. As four patients had incomplete protocols, they were not included in the final analysis. 4% of the patients referred to endodontic clinics during the study period were examined with CBCT. The most frequent reason for referral to CBCT examination was to differentiate pathology from normal anatomy, this was the case in 24 patients (45% of the cases). The primary outcome was therapy plan changes that could be attributed to CBCT examination. There were changes in 28 patients (53%). CBCT has a significant impact on therapeutic decision efficacy in endodontics when used in concordance with the current European Commission guidelines.

  19. Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography.

    Science.gov (United States)

    Kim, Jooseong; Heo, Giseon; Lagravère, Manuel O

    2014-05-01

    To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

  20. Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Isabela Maria de Carvalho Crusoé Silva

    2012-12-01

    Full Text Available The aim of this study was to evaluate the validity of the bone density value of potential implant sites in HU obtained by a specific cone-beam computed tomography (CBCT device. In this study, the HU values obtained using a MSCT scanner were used as the gold standard. Twenty mandibles (40 potential implant sites were scanned using an MSCT scanner (Somatom Sensation 40 and a CBCT scanner (i-CAT. The MSCT images were evaluated using the Syngo CT Workplace software and the CBCT images, using the XoranCat software. The images were evaluated twice by three oral radiologists, at 60 day intervals. The trabecular bone density of the same area was evaluated on both images. Intraclass coefficients (ICC were calculated to examine the agreement between the examiners and between the two periods of evaluation. The bone density and area of the ROI were compared by the Student t test and Bland-Altman analysis. ICCs were excellent. The mean HU value obtained using CBCT (418.06 was higher than that obtained using MSCT (313.13, with a statistically significant difference (p < 0.0001. In addition, Bland-Altman analysis showed that the HU measures were not equivalent. In conclusion, the bone density in HU with CBCT images obtained using the device studied proved unreliable, since it was higher than that obtained using MSCT.

  1. Salivary calculus diagnosis with 3-dimensional cone-beam computed tomography.

    Science.gov (United States)

    Dreiseidler, Timo; Ritter, Lutz; Rothamel, Daniel; Neugebauer, Jörg; Scheer, Martin; Mischkowski, Robert A

    2010-07-01

    The objective of this study was to evaluate cone-beam CT (CBCT) diagnoses of sialoliths in the major salivary glands. Twenty-nine CBCT images containing salivary calculi were retrospectively evaluated for image quality and artifact influence. Additionally, the reproducibility of calculus measurement and the differences between CBCT measurements and ultrasonography (US) and histomorphometry (HM) measurements were determined. Diagnostic sensitivity and specificity calculations were based on the observations of 3 masked clinicians, who reviewed a total of 58 CBCT volumes. Salivary calculi were sufficiently visualized in all patients. Metal artifacts were detected in images of 7 patients, and movement artifacts in 2. CBCT calculi measurements were highly reproducible, with mean differences of less than 350 microm. Mean CBCT measurements of calculi diameters differed from mean US measurements by approximately 500 microm and differed from mean HM measurements by approximately 1 mm. For calculus diagnoses, the mean sensitivity and specificity were both 98.85%. Although poor image qualities and artifacts can reduce diagnostic information, salivary calculi can be evaluated adequately with CBCT. CBCT measurements of calculi are highly reproducible and differ little from measurements made with US and HM. Diagnostic sensitivity and specificity levels with CBCT are as high as or higher than those obtained with other diagnostic methods. Because of its high diagnostic-information-to-radiation-dose ratio, CBCT is the preferable imaging modality for salivary calculus diagnosis. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  2. The current status of cone beam computed tomography imaging in orthodontics.

    Science.gov (United States)

    Kapila, S; Conley, R S; Harrell, W E

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations.

  3. Volumetric analysis of the mandibular condyle using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Mehmet, E-mail: dtmehmetbayram@yahoo.com [Karadeniz Technical University, Faculty of Dentistry, Department of Orthodontics, 61080 Trabzon (Turkey); Kayipmaz, Saadettin; Sezgin, Oemer Said [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Radiology, Trabzon (Turkey); Kuecuek, Murat [Karadeniz Technical University, Faculty of Arts and Sciences, Department of Chemistry, Trabzon (Turkey)

    2012-08-15

    Objective: The aim was to determine the accuracy of volumetric analysis of the mandibular condyle using cone-beam computed tomography (CBCT). Materials and methods: Five dry mandibles containing 9 condyles were used. CBCT scans of the mandibles and an impression of each condylar area were taken. The physical volumes of the condyles were calculated as the gold standard using the water displacement technique. After isolating, the condylar volume was sectioned in the sagittal plane, and 0.3 mm thick sections with 0.9 mm intervals were obtained from 3D reconstructions. Using the Cavalieri principle, the volume of each condyle was estimated from the CBCT images by three observers. The accuracy of the CBCT volume measurements and the relation agreements between the results of the three observers were assessed using the Wilcoxon Signed Rank test and Pearson correlation test. The level of statistical significance was set at 0.05. Results: The results of the Pearson correlation showed that there were highly significant positive correlations between the observers' measurements. According to the results of the Wilcoxon Signed Rank test comparing the physical and observers' measurements, there were no statistically significant differences (p > 0.05). Conclusion: The Cavalieri principle, used in conjunction with a planimetry method, is a valid and effective method for volume estimation of the mandibular condyle on CBCT images.

  4. Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Mi Ree; Moon, Young Mi; Seo, Min Seock [Dept. of Conservative Dentistry, Wonkang University Daejeon Dental Hospital, Daejeon (Korea, Republic of)

    2015-12-15

    This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

  5. Upper airway segmentation and dimensions estimation from cone-beam CT image datasets

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Hongjian; Scarfe, W.C. [Louisville Univ., KY (United States). School of Dentistry; Farman, A.G. [Louisville Univ., KY (United States). School of Dentistry; Louisville Univ., KY (United States). Div. of Radiology and Imaging Science

    2006-11-15

    Objective: To segment and measure the upper airway using cone-beam computed tomography (CBCT). This information may be useful as an imaging biomarker in the diagnostic assessment of patients with obstructive sleep apnea and in the planning of any necessary therapy. Methods: With Institutional Review Board Approval, anonymous CBCT datasets from subjects who had been imaged for a variety of conditions unrelated to the airway were evaluated. DICOM images were available. A segmentation algorithm was developed to separate the bounded upper airway and measurements were performed manually to determine the smallest cross-sectional area and the anteriorposterior distance of the retropalatal space (RP-SCA and RP-AP, respectively) and retroglossal space (RG-SCA and RG-AP, respectively). A segmentation algorithm was developed to separate the bounded upper airway and it was applied to determine RP-AP, RG-AP, the smallest transaxial-sectional area (TSCA) and largest sagittal view airway area (LCSA). A second algorithm was created to evaluate the airway volume within this bounded upper airway. Results: Measurements of the airway segmented automatically by the developed algorithm agreed with those obtained using manual segmentation. The corresponding volumes showed only very small differences considered clinically insignificant. Conclusion: Automatic segmentation of the airway imaged using CBCT is feasible and this method can be used to evaluate airway cross-section and volume comparable to measurements extracted using manual segmentation. (orig.)

  6. Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept.of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2015-12-15

    This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images.

  7. Accuracy of digital peripical radiography and cone-beam computed tomography in detecting external root resorption

    Energy Technology Data Exchange (ETDEWEB)

    Creanga, Adriana Gabriela [Division of Dental Diagnostic Science, Rutgers School of Dental Medicine, Newark (United States); Geha, Hassem; Sankar, Vidya; Mcmahan, Clyde Alex; Noujeim, Marcel [University of Texas Health Science Center San Antonio, San Antonio (United States); Teixeira, Fabrico B. [Dept. of Endodontics, University of Iowa, Iowa City (United States)

    2015-09-15

    The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities. Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement. A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level. CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

  8. Idiosyncratic Presentation of Cemento-Osseous Dysplasia - An in Depth Analysis Using Cone Beam Computed Tomography.

    Science.gov (United States)

    Chennoju, Sai Kiran; Pachigolla, Ramaswamy; Govada, Vanya Mahitha; Alapati, Satish; Balla, Smitha

    2016-05-01

    Bone dysplasias comprise of a condition where the normal bone is replaced with fibrous tissue. Periapical Cemento-Osseous Dysplasia (PCOD) is a benign fibro-osseous condition where bone tissue is supplanted with fibrous tissue and cementum-like material. This condition affects mostly mandibular anterior region and rarely occurs in the maxilla. PCOD is seen above 30 years of age and has slight female predilection. Generally the teeth related to such lesions appear to be vital and are usually asymptomatic. These lesions are mostly seen during routine radiographic examination whose presentation may vary from complete radiolucency to dense radiopacity. The advent of Cone Beam Computed Tomography (CBCT) has brought a massive change in the field of dentistry which has become an important tool for diagnosis. Hence we hereby present an unusual case of cemento-osseous dysplasia in an unfamiliar location with an atypical presentation. The shape of the pathology was completely idiosyncratic and different from an orthodox lesion of COD, as the lesion was observed to grow out of the palatal surface with a prominent palatal expansion. This case highlights the importance of CBCT in radiographic diagnosis and in evaluating the characteristics of such lesion, which present with high diagnostic dilemma.

  9. The geometric calibration of cone-beam imaging and delivery systems in radiation therapy

    CERN Document Server

    Matsinos, E; Kaissl, Wolfgang; Matsinos, Evangelos

    2006-01-01

    We propose a method to achieve the geometric calibration of cone-beam imaging and delivery systems in radiation therapy; our approach applies to devices where an X-ray source and a flat-panel detector, facing each other, move in circular orbits around the irradiated object. In order to extract the parameters of the geometry from the data, we use a light needle phantom which is easy to manufacture. A model with ten free parameters (spatial lengths and distortion angles) has been put forth to describe the geometry and the mechanical imperfections of the units being calibrated; a few additional parameters are introduced to account for residual effects (small effects which lie beyond our model). The values of the model parameters are determined from one complete scan of the needle phantom via a robust optimisation scheme. The application of this method to two sets of five counterclockwise (ccw) and five clockwise (cw) scans yielded consistent and reproducible results. A number of differences have been observed be...

  10. Accuracy and precision of cone beam computed tomography in periodontal defects measurement (systematic review).

    Science.gov (United States)

    Anter, Enas; Zayet, Mohammed Khalifa; El-Dessouky, Sahar Hosny

    2016-01-01

    Systematic review of literature was made to assess the extent of accuracy of cone beam computed tomography (CBCT) as a tool for measurement of alveolar bone loss in periodontal defect. A systematic search of PubMed electronic database and a hand search of open access journals (from 2000 to 2015) yielded abstracts that were potentially relevant. The original articles were then retrieved and their references were hand searched for possible missing articles. Only articles that met the selection criteria were included and criticized. The initial screening revealed 47 potentially relevant articles, of which only 14 have met the selection criteria; their CBCT average measurements error ranged from 0.19 mm to 1.27 mm; however, no valid meta-analysis could be made due to the high heterogeneity between the included studies. Under the limitation of the number and strength of the available studies, we concluded that CBCT provides an assessment of alveolar bone loss in periodontal defect with a minimum reported mean measurements error of 0.19 ± 0.11 mm and a maximum reported mean measurements error of 1.27 ± 1.43 mm, and there is no agreement between the studies regarding the direction of the deviation whether over or underestimation. However, we should emphasize that the evidence to this data is not strong.

  11. Bilateral and pseudobilateral tonsilloliths: Three dimensional imaging with cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Misirlioglu, Melda; Adisen, Mehmet Zahit; Yardimci, Selmi [Dept. of Oral and Maxillofacial Radiology, Faculty of Dentistry, Kirikkale University, Kirikkale (Turkmenistan); Nalcaci, Rana [Dept. of Oral and Maxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara (Turkmenistan)

    2013-09-15

    Tonsilloliths are calcifications found in the crypts of the palatal tonsils and can be detected on routine panoramic examinations. This study was performed to highlight the benefits of cone-beam computed tomography (CBCT) in the diagnosis of tonsilloliths appearing bilaterally on panoramic radiographs. The sample group consisted of 7 patients who had bilateral radiopaque lesions at the area of the ascending ramus on panoramic radiographs. CBCT images for every patient were obtained from both sides of the jaw to determine the exact locations of the lesions and to rule out other calcifications. The calcifications were evaluated on the CBCT images using Ez3D2009 software. Additionally, the obtained images in DICOM format were transferred to ITK SNAP 2.4.0 pc software for semiautomatic segmentation. Segmentation was performed using contrast differences between the soft tissues and calcifications on grayscale images, and the volume in mm{sup 3} of the segmented three dimensional models were obtained. CBCT scans revealed that what appeared on panoramic radiographs as bilateral images were in fact unilateral lesions in 2 cases. The total volume of the calcifications ranged from 7.92 to 302.5mm{sup 3}. The patients with bilaterally multiple and large calcifications were found to be symptomatic. The cases provided the evidence that tonsilloliths should be considered in the differential diagnosis of radiopaque masses involving the mandibular ramus, and they highlight the need for a CBCT scan to differentiate pseudo- or ghost images from true bilateral pathologies.

  12. Three-dimensional focus of attention for iterative cone-beam micro-CT reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Benson, T M; Gregor, J [Department of Computer Science, University of Tennessee, Knoxville, Tennessee 37996-3450 (United States)

    2006-09-21

    Three-dimensional iterative reconstruction of high-resolution, circular orbit cone-beam x-ray CT data is often considered impractical due to the demand for vast amounts of computer cycles and associated memory. In this paper, we show that the computational burden can be reduced by limiting the reconstruction to a small, well-defined portion of the image volume. We first discuss using the support region defined by the set of voxels covered by all of the projection views. We then present a data-driven preprocessing technique called focus of attention that heuristically separates both image and projection data into object and background before reconstruction, thereby further reducing the reconstruction region of interest. We present experimental results for both methods based on mouse data and a parallelized implementation of the SIRT algorithm. The computational savings associated with the support region are substantial. However, the results for focus of attention are even more impressive in that only about one quarter of the computer cycles and memory are needed compared with reconstruction of the entire image volume. The image quality is not compromised by either method.

  13. Contrast-enhanced angiographic cone-beam computed tomography without pre-diluted contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Jo, K.I.; Kim, S.R.; Choi, J.H.; Kim, K.H.; Jeon, P. [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Gangnam-gu, Seoul (Korea, Republic of)

    2015-11-15

    Contrast-enhanced cone-beam computed tomography (CBCT) has been introduced and accepted as a useful technique to evaluate delicate vascular anatomy and neurovascular stents. Current protocol for CBCT requires quantitative dilution of contrast medium to obtain adequate quality images. Here, we introduce simple methods to obtain contrast-enhanced CBCT without quantitative contrast dilution. A simple experiment was performed to estimate the change in flow rate in the internal carotid artery during the procedure. Transcranial doppler (TCD) was used to evaluate the velocity change before and after catheterization and fluid infusion. In addition, 0.3 cm{sup 3}/s (n = 3) and 0.2 cm{sup 3}/s (n = 7) contrast infusions were injected and followed by saline flushes using a 300 mmHg pressure bag to evaluate neurovascular stent and host arteries. Flow velocities changed -15 ± 6.8 % and +17 ± 5.5 % from baseline during catheterization and guiding catheter flushing with a 300 mmHg pressure bag, respectively. Evaluation of the stents and vascular structure was feasible using this technique in all patients. Quality assessment showed that the 0.2 cm{sup 3}/s contrast infusion protocol was better for evaluating the stent and host artery. Contrast-enhanced CBCT can be performed without quantitative contrast dilution. Adequate contrast dilution can be achieved with a small saline flush and normal blood flow. (orig.)

  14. Segmentation of cone-beam CT using a hidden Markov random field with informative priors

    Science.gov (United States)

    Moores, M.; Hargrave, C.; Harden, F.; Mengersen, K.

    2014-03-01

    Cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. The rich sources of prior information in IGRT are incorporated into a hidden Markov random field model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk. The voxel labels are estimated using iterated conditional modes. The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom. The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.

  15. Validating cone-beam computed tomography for peri-implant bone morphometric analysis

    Institute of Scientific and Technical Information of China (English)

    Yan Huang; Jeroen Van Dessel; Maarten Depypere; Mostafa EzEldeen; Alexandru Andrei Iliescu; Emanuela Dos Santos; Ivo Lambrichts; Xin Liang; Reinhilde Jacobs

    2014-01-01

    Cone-beam computed tomography (CBCT) has been recently used to analyse trabecular bone structure around dental implants. To validate the use of CBCT for three-dimensional (3D) peri-implant trabecular bone morphometry by comparing it to two-dimensional (2D) histology, 36 alveolar bone samples (with implants n527 vs. without implants n59) from six mongrel dogs, were scanned ex vivo using a high-resolution (80 mm) CBCT. After scanning, all samples were decalcified and then sectioned into thin histological sections (,6 mm) to obtain high contrast 2D images. By using CTAn imaging software, bone morphometric parameters including trabecular number (Tb.N), thickness (Tb.Th), separation (Tb.Sp) and bone volume fraction (BV/TV) were examined on both CBCT and corresponding histological images. Higher Tb.Th and Tb.Sp, lower BV/TV and Tb.N were found on CBCT images (P,0.001). Both measurements on the peri-implant trabecular bone structure showed moderate to high correlation (r50.65-0.85). The Bland-Altman plots showed strongest agreement for Tb.Th followed by Tb.Sp, Tb.N and BV/TV, regardless of the presence of implants. The current findings support the assumption that peri-implant trabecular bone structures based on high-resolution CBCT measurements are representative for the underlying histological bone characteristics, indicating a potential clinical diagnostic use of CBCT-based peri-implant bone morphometric characterisation.

  16. Effective dose estimates for cone beam computed tomography in interventional radiology

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Y.M.; Irani, F.G.; Tay, K.H.; Yang, C.C.; Padre, C.G.; Tan, B.S. [Singapore General Hospital, Department of Diagnostic Radiology, Singapore (Singapore)

    2013-11-15

    To compare radiation doses in cone beam computed tomography (CBCT) with those of multi-detector computed tomography (MDCT) using manufacturers' standard protocols. Dose-levels in head and abdominal imaging were evaluated using a dosimetric phantom. Effective dose estimates were performed by placing thermoluminescent dosimeters in the phantom. Selected protocols for two CBCT systems and comparable protocols for one MDCT system were evaluated. Organ doses were measured and effective doses derived by applying the International Commission on Radiological Protection 2007 tissue weighting factors. Effective doses estimated for the head protocol were 4.4 and 5.4 mSv for the two CBCT systems respectively and 4.3 mSv for MDCT. Eye doses for one CBCT system and MDCT were comparable (173.6 and 148.4 mGy respectively) but significantly higher compared with the second CBCT (44.6 mGy). Two abdominal protocols were evaluated for each system; the effective doses estimated were 15.0 and 18.6 mSv, 25.4 and 37.0 mSv, and 9.8 and 13.5 mSv, respectively, for each of the CBCT and MDCT systems. The study demonstrated comparable dose-levels for CBCT and MDCT systems in head studies, but higher dose levels for CBCT in abdominal studies. There was a significant difference in eye doses observed between the CBCT systems. (orig.)

  17. Tooth labeling in cone-beam CT using deep convolutional neural network for forensic identification

    Science.gov (United States)

    Miki, Yuma; Muramatsu, Chisako; Hayashi, Tatsuro; Zhou, Xiangrong; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

    2017-03-01

    In large disasters, dental record plays an important role in forensic identification. However, filing dental charts for corpses is not an easy task for general dentists. Moreover, it is laborious and time-consuming work in cases of large scale disasters. We have been investigating a tooth labeling method on dental cone-beam CT images for the purpose of automatic filing of dental charts. In our method, individual tooth in CT images are detected and classified into seven tooth types using deep convolutional neural network. We employed the fully convolutional network using AlexNet architecture for detecting each tooth and applied our previous method using regular AlexNet for classifying the detected teeth into 7 tooth types. From 52 CT volumes obtained by two imaging systems, five images each were randomly selected as test data, and the remaining 42 cases were used as training data. The result showed the tooth detection accuracy of 77.4% with the average false detection of 5.8 per image. The result indicates the potential utility of the proposed method for automatic recording of dental information.

  18. Precision of cephalometric landmark identification: Cone-beam computed tomography vs conventional cephalometric views

    Science.gov (United States)

    Ludlow, John B.; Gubler, Maritzabel; Cevidanes, Lucia; Mol, André

    2009-01-01

    Introduction In this study, we compared the precision of landmark identification using displays of multi-planar cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). Methods Twenty presurgical orthodontic patients were radiographed with conventional Ceph and CBCT techniques. Five observers plotted 24 landmarks using computer displays of multi-planer reconstruction (MPR) CBCT and Ceph views during separate sessions. Absolute differences between each observer’s plot and the mean of all observers were averaged as 1 measure of variability (ODM). The absolute difference of each observer from any other observer was averaged as a second measure of variability (DEO). ANOVA and paired t tests were used to analyze variability differences. Results Radiographic modality and landmark were significant at P <0.0001 for DEO and ODM calculations. DEO calculations of observer variability were consistently greater than ODM. The overall correlation of 1920 paired ODM and DEO measurements was excellent at 0.972. All bilateral landmarks had increased precision when identified in the MPR views. Mediolateral variability was statistically greater than anteroposterior or caudal-cranial variability for 5 landmarks in the MPR views. Conclusions The MPR displays of CBCT volume images provide generally more precise identification of traditional cephalometric landmarks. More precise location of condylion, gonion, and orbitale overcomes the problem of superimposition of these bilateral landmarks seen in Ceph. Greater variability of certain landmarks in the mediolateral direction is probably related to inadequate definition of the landmarks in the third dimension. PMID:19732656

  19. Image analysis and superimposition of 3-dimensional cone-beam computed tomography models

    Science.gov (United States)

    Cevidanes, Lucia H. S.; Styner, Martin A.; Proffit, William R.

    2013-01-01

    Three-dimensional (3D) imaging techniques can provide valuable information to clinicians and researchers. But as we move from traditional 2-dimensional (2D) cephalometric analysis to new 3D techniques, it is often necessary to compare 2D with 3D data. Cone-beam computed tomography (CBCT) provides simulation tools that can help bridge the gap between image types. CBCT acquisitions can be made to simulate panoramic, lateral, and posteroanterior cephalometric radioagraphs so that they can be compared with preexisting cephalometric databases. Applications of 3D imaging in orthodontics include initial diagnosis and superimpositions for assessing growth, treatment changes, and stability. Three-dimensional CBCT images show dental root inclination and torque, impacted and supernumerary tooth positions, thickness and morphology of bone at sites of mini-implants for anchorage, and osteotomy sites in surgical planning. Findings such as resorption, hyperplasic growth, displacement, shape anomalies of mandibular condyles, and morphological differences between the right and left sides emphasize the diagnostic value of computed tomography acquisitions. Furthermore, relationships of soft tissues and the airway can be assessed in 3 dimensions. PMID:16679201

  20. Pharyngeal airway volume and shape from cone-beam computed tomography: Relationship to facial morphology

    Science.gov (United States)

    Grauer, Dan; Cevidanes, Lucia S. H.; Styner, Martin A.; Ackerman, James L.; Proffit, William R.

    2010-01-01

    Introduction The aim of this study was to assess the differences in airway shape and volume among subjects with various facial patterns. Methods Cone-beam computed tomography records of 62 nongrowing patients were used to evaluate the pharyngeal airway volume (superior and inferior compartments) and shape. This was done by using 3-dimensional virtual surface models to calculate airway volumes instead of estimates based on linear measurements. Subgroups of the sample were determined by anteroposterior jaw relationships and vertical proportions. Results There was a statistically significant relationship between the volume of the inferior component of the airway and the anteroposterior jaw relationship (P = 0.02), and between airway volume and both size of the face and sex (P = 0.02, P = 0.01). No differences in airway volumes related to vertical facial proportions were found. Skeletal Class II patients often had forward inclination of the airway (P <0.001), whereas skeletal Class III patients had a more vertically oriented airway (P = 0.002). Conclusions Airway volume and shape vary among patients with different anteroposterior jaw relationships; airway shape but not volume differs with various vertical jaw relationships. The methods developed in this study make it possible to determine the relationship of 3-dimensional pharyngeal airway surface models to facial morphology, while controlling for variability in facial size. PMID:19962603

  1. Prevalence and characteristics of pneumatization of the temporal bone evaluated by cone beam computed tomography.

    Science.gov (United States)

    Ladeira, D B S; Barbosa, G L R; Nascimento, M C C; Cruz, A D; Freitas, D Q; Almeida, S M

    2013-06-01

    The aim of this study was to determine the prevalence and characteristics of pneumatization of the glenoid fossa and articular eminence by means of cone beam computed tomography (CBCT) images. CBCT images of 658 patients (1316 joints) were evaluated to determine pneumatization in the articular eminence (PAT) and roof of the glenoid fossa (PGF). Age and gender were recorded for all patients and, for the cases of pneumatization, laterality and type (unilocular or multilocular) were noted. Its prevalence was correlated with gender, age and laterality by statistical analyses. 21.3% of individuals presented with PAT and 38.3% presented with PGF. Considering the temporomandibular joint, PAT was in 15.5% and PGF in 30.2%. Of PAT cases, 54.3% were unilateral and 45.7% bilateral; 3.4% were unilocular and 96.6% were multilocular. In the PGF cases, 42.5% were unilateral and 57.5% bilateral; 0.02% was unilocular and 99.8% were multilocular. There was no statistical difference regarding gender and age; but there was statistical difference regarding laterality, with higher frequency on the left side. In conclusion, there was a significant prevalence of PAT and PGF in the studied population; their prevalence seems higher than has been previously supposed.

  2. Cone-beam computed tomography as a surgical guide to impacted anterior teeth

    Directory of Open Access Journals (Sweden)

    Fabiano Jeremias

    2016-01-01

    Full Text Available Surgical procedure for removal of impacted teeth is a challenge for clinicians as it involves accuracy in the diagnosis and localization of the dental elements. The cone-beam computed tomography (CBCT, compared to the conventional radiography, has a greater potential to provide complementary information because of its three-dimensional (3D images, reducing the possibility of failures in surgical procedures. Two 10-year-old boys presented with aesthetic issues associated with the juxtaposition of ectopic teeth with the permanent ones. Both two-dimensional and 3D preoperative radiographic diagnostic sets were produced. The occlusal and panoramic radiographs were not enough for proper localization of impacted incisors. Thus, the CBCT was used as a surgical guide. After 2 years of longitudinal following, no lesion was recorded, and the orthodontic treatment has proven successful. In all cases, CBCT contributed to both diagnosis and correct localization of supernumerary teeth, aiding the professional in the treatment planning, and consequently in the clinical success. The surgeries were completely safe, avoiding damage in noble structures, and providing a better recovering of the patients.

  3. Implementation of the FDK algorithm for cone-beam CT on the cell broadband engine architecture

    Science.gov (United States)

    Scherl, Holger; Koerner, Mario; Hofmann, Hannes; Eckert, Wieland; Kowarschik, Markus; Hornegger, Joachim

    2007-03-01

    In most of today's commercially available cone-beam CT scanners, the well known FDK method is used for solving the 3D reconstruction task. The computational complexity of this algorithm prohibits its use for many medical applications without hardware acceleration. The brand-new Cell Broadband Engine Architecture (CBEA) with its high level of parallelism is a cost-efficient processor for performing the FDK reconstruction according to the medical requirements. The programming scheme, however, is quite different to any standard personal computer hardware. In this paper, we present an innovative implementation of the most time-consuming parts of the FDK algorithm: filtering and back-projection. We also explain the required transformations to parallelize the algorithm for the CBEA. Our software framework allows to compute the filtering and back-projection in parallel, making it possible to do an on-the-fly-reconstruction. The achieved results demonstrate that a complete FDK reconstruction is computed with the CBEA in less than seven seconds for a standard clinical scenario. Given the fact that scan times are usually much higher, we conclude that reconstruction is finished right after the end of data acquisition. This enables us to present the reconstructed volume to the physician in real-time, immediately after the last projection image has been acquired by the scanning device.

  4. Cone-Beam Computed Tomography and Radiographs in Dentistry: Aspects Related to Radiation Dose

    Directory of Open Access Journals (Sweden)

    Diego Coelho Lorenzoni

    2012-01-01

    Full Text Available Introduction. The aim of this study was to discuss the radiation doses associated with plain radiographs, cone-beam computed tomography (CBCT, and conventional computed tomography (CT in dentistry, with a special focus on orthodontics. Methods. A systematic search for articles was realized by MEDLINE from 1997–March 2011. Results. Twenty-seven articles met the established criteria. The data of these papers were grouped in a table and discussed. Conclusions. Increases in kV, mA, exposure time, and field of view (FOV increase the radiation dose. The dose for CT is greater than other modalities. When the full-mouth series (FMX is performed with round collimation, the orthodontic radiographs transmit higher dose than most of the large FOV CBCT, but it can be reduced if used rectangular collimation, showing lower effective dose than large FOV CBCT. Despite the image quality, the CBCT does not replace the FMX. In addition to the radiation dose, image quality and diagnostic needs should be strongly taken into account.

  5. Digital orthodontic radiographic set versus cone-beam computed tomography: an evaluation of the effective dose

    Science.gov (United States)

    Chinem, Lillian Atsumi Simabuguro; Vilella, Beatriz de Souza; Maurício, Cláudia Lúcia de Pinho; Canevaro, Lucia Viviana; Deluiz, Luiz Fernando; Vilella, Oswaldo de Vasconcellos

    2016-01-01

    ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digital radiographic methods (panoramic, lateral cephalometric and periapical) with cone-beam computed tomography (CBCT). Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA), representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany), Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany) and i-CAT (Imaging Sciences International, Hatfield, PA, USA). The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP) issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990) and 47.2% (ICRP 2007) of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination. PMID:27653266

  6. SADMFR guidelines for the use of Cone-Beam Computed Tomography/ Digital Volume Tomography.

    Science.gov (United States)

    Dula, Karl; Bornstein, Michael M; Buser, Daniel; Dagassan-Berndt, Dorothea; Ettlin, Dominik A; Filippi, Andreas; Gabioud, François; Katsaros, Christos; Krastl, Gabriel; Lambrecht, J Thomas; Lauber, Roland; Luebbers, Heinz-Theo; Pazera, Pawel; Türp, Jens C

    2014-01-01

    Cone-Beam Computed Tomography (CBCT) has been introduced in 1998. This radiological imaging procedure has been provided for dentistry and is comparable to computed tomography (CT) in medicine. It is expected that CBCT will have the same success in dental diagnostic imaging as computed tomography had in medicine. Just as CT is responsible for a significant rise in radiation dose to the population from medical X-ray diagnostics, CBCT studies will be accompanied by a significant increase of the dose to our patients by dentistry. Because of the growing concern for an uncritical and consequently rapidly increasing use of CBCT the Swiss Society of Dentomaxillofacial Radiology convened a first consensus conference in 2011 to formulate indications for CBCT, which can be used as guidelines. In this meeting, oral and maxillofacial surgery, orthodontics and temporomandibular joint disorders and diseases were treated and the most important and most experienced users of DVT in these areas were asked to participate. In general, a highly restrictive use of CBCT is required. Justifying main criterion for CBCT application is that additional, therapy-relevant information is expected that should lead to a significant benefit in patient care. All users of CBCT should have completed a structured, high-level training, just like that offered by the Swiss Society of Dentomaxillofacial Radiology.

  7. Cone-Beam computed tomography evaluation of maxillary expansion in twins with cleft lip and palate

    Directory of Open Access Journals (Sweden)

    Luciane Macedo de Menezes

    2012-04-01

    Full Text Available OBJECTIVE: The establishment of normal occlusal relationships in patients with cleft lip and palate using rapid maxillary expansion may promote good conditions for future rehabilitation. OBJECTIVE: This study describes the clinical case of monozygotic twins with unilateral cleft lip and palate at the age of mixed dentition, who were treated using the same rapid maxillary expansion protocol, but with two different screws (conventional and fan-type expansion screw. Results were evaluated using plaster models, intraoral and extraoral photographs, and Cone-Beam computed tomography (CBCT scans obtained before the beginning of the treatment, (T1. METHODS: The patients were followed up for 6 months after maxillary expansion, when the same tests requested at T1 were obtained again for review (T2. T1 and T2 results were compared using lateral cephalometric tracings and measurements of the intercanine and intermolar distances in the plaster models using a digital caliper. RESULTS: The two types of expansion screws corrected the transverse discrepancy in patients with cleft lip and palate. The shape of the upper arches improved at 10 days after activation. CONCLUSION: CBCT scans provide detailed information about craniofacial, maxillary and mandibular changes resulting from rapid maxillary expansion. The most adequate screw for each type of malocclusion should be chosen after detailed examination of the dental arches.

  8. Reliability of a method to conduct upper airway analysis in cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Karen Regina Siqueira de Souza

    2013-02-01

    Full Text Available The aim of this study was to assess the reliability of a method to measure the following upper airway dimensions: total volume (TV, the nasopharyngeal narrowest areas (NNA, and the oropharyngeal narrowest areas (ONA. The sample consisted of 60 cone-beam computed tomography (CBCT scans, evaluated by two observers twice, using the Dolphin 3D software (Dolphin Imaging & Management solutions, Chatsworth, California, USA, which afforded image reconstruction, and measurement of the aforementioned dimensions. The data was submitted to reliability tests, by the intraclass correlation coefficient (ICC, and the Bland & Altman agreement tests, with their respective confidence intervals (CI set at 95%. Excellent intra- and interobserver reliability values were found for all variables assessed (TV, NNA and ONA, with ICC values ranging from 0.88 to 0.99. The data demonstrated an agreement between the two assessments of each observer and between the first evaluations of both observers, thus confirming the reliability of this methodology. The results suggest that this methodology can be used in further studies to investigate upper airway dimensions (TV, NNA, and ONA, thereby contributing to the diagnosis of upper airway obstructions.

  9. Dosimetry of cone beam computed tomography scanning for diagnosis and planning in implant dentistry

    Energy Technology Data Exchange (ETDEWEB)

    Santos Pinto de A, E. L.; Manzi, F. R.; Goncalves Z, E. [Pontifical Catholic University of Minas Gerais, Av. Jose Gaspar 500, 30535-901 Belo Horizonte, Minas Gerais (Brazil); Nogueira, M. S.; Fernandes Z, M. A., E-mail: madelon@cdtn.br [Development Center of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: The radiation dose and estimate the radiation induced risk of cancer and morpho functional alterations according to BEIR VII (2006) and recommendations of the ICRP 103 (2007) were measured in cone beam computed tomography (CBCT) scanning (Tc Kodak 9000C 3D) in different oral and maxillofacial regions for diagnosis and planning in implant dentistry for each examination protocol: jaw full, maxilla full and jaw and maxilla full associated. Thermoluminescent dosimeters (TLD- 100 H) were placed in an Alderson-Rando in regions corresponding to the crystalline, parotid, submandibular and thyroid glands and ovaries. The highest values for entrance skin dose were observed in the region of the parotid and submandibular glands, 9.612 mGy to 7.912 mGy and 8.818 mGy to 0.483 mGy, respectively. All examination protocols presented on the right and left sides in the region of the submandibular gland the highest values for absorbed dose (D). In the jaw full exam the thyroid glands on both sides presented highest dose values than maxilla full exam. This study allowed measuring the entrance skin dose and the absorbed dose (D) highlighting a dosimetric preponderance to the salivary glands. With danger of to radiation that induces cancer risk was observed that the age group most likely to have to risk of cancer was 20 years, compared to 30, 40, 50, 60,70 and 80 years. (Author)

  10. [Development of computer assisted learning program using cone beam projection for head radiography].

    Science.gov (United States)

    Nakazeko, Kazuma; Kajiwara, Hironori; Watanabe, Hiroyuki; Kuwayama, Jun; Karube, Shuhei; Araki, Misao; Hashimoto, Takeyuki; Shinohara, Hiroyuki

    2012-01-01

    We present a computer assisted learning (CAL) program to simulate head radiography. The program provides cone beam projections of a target volume, simulating three-dimensional computed tomography (CT) of a head phantom. The generated image is 512 x 512 x 512 pixels with each pixel 0.6 mm on a side. The imaging geometry, such as X-ray tube orientation and phantom orientation, can be varied. The graphical user interface (GUI) of the CAL program allows the study of the effects of varying the imaging geometry; each simulated projection image is shown quickly in an adjoining window. Simulated images with an assigned geometry were compared with the image obtained using the standard geometry in clinical use. The accuracy of the simulated image was verified through comparison with the image acquired using radiography of the head phantom, subsequently processed with a computed radiography system (CR image). Based on correlation coefficient analysis and visual assessment, it was concluded that the CAL program can satisfactorily simulate the CR image. Therefore, it should be useful for the training of head radiography.

  11. Simultaneous calibration phantom commission and geometry calibration in cone beam CT

    Science.gov (United States)

    Xu, Yuan; Yang, Shuai; Ma, Jianhui; Li, Bin; Wu, Shuyu; Qi, Hongliang; Zhou, Linghong

    2017-09-01

    Geometry calibration is a vital step for describing the geometry of a cone beam computed tomography (CBCT) system and is a prerequisite for CBCT reconstruction. In current methods, calibration phantom commission and geometry calibration are divided into two independent tasks. Small errors in ball-bearing (BB) positioning in the phantom-making step will severely degrade the quality of phantom calibration. To solve this problem, we propose an integrated method to simultaneously realize geometry phantom commission and geometry calibration. Instead of assuming the accuracy of the geometry phantom, the integrated method considers BB centers in the phantom as an optimized parameter in the workflow. Specifically, an evaluation phantom and the corresponding evaluation contrast index are used to evaluate geometry artifacts for optimizing the BB coordinates in the geometry phantom. After utilizing particle swarm optimization, the CBCT geometry and BB coordinates in the geometry phantom are calibrated accurately and are then directly used for the next geometry calibration task in other CBCT systems. To evaluate the proposed method, both qualitative and quantitative studies were performed on simulated and realistic CBCT data. The spatial resolution of reconstructed images using dental CBCT can reach up to 15 line pair cm-1. The proposed method is also superior to the Wiesent method in experiments. This paper shows that the proposed method is attractive for simultaneous and accurate geometry phantom commission and geometry calibration.

  12. A Comparison of the Amounts of Artifacts Produced by Five Cements in Cone-Beam CT

    Directory of Open Access Journals (Sweden)

    Moshfeghi

    2016-02-01

    Full Text Available Background Bidimensional radiographic methods, including periapical, occlusal, panoramic, and cephalometric radiographs, are widely used in dentistry. However, the superimposition of adjacent structures and consequent loss of anatomic details may occur. Objectives The purpose of this study is to evaluate the artifacts produced by different cements with different densities using cone-beam computed tomography (CBCT. Materials and Methods Samples of five cements with different densities including glass ionomers (or GI, from ChemFil Rock and Fuji IX, mineral trioxide aggregates (MTA, zinc oxide eugenol (ZOE, TempBond and a control sample (polyester were scanned by CBCT device and analyzed using OnDemand 3D application software. The amount of artifacts was measured by ∆ gray scale value (∆GSV, which was achieved by subtracting the gray level of the samples from the control group. Results According to the mean GSV of the five different materials, the majority of artifacts produced were as follows: TempBond > ZOE > MTA > GI (ChemFil Dentsply > GI (GC, Fuji ΙX. Conclusions The type of materials can influence the obtained GSV. Different materials cause various amounts of artifacts due to differences in density and atomic number.

  13. Clinical usefulness of c-arm cone-beam CT inpercutaneous drainage of inaccessible abscess

    Energy Technology Data Exchange (ETDEWEB)

    So, Young Ho; Choi, Young Ho; Woo, Hyun Sik; Moon, Min Hoan; Sung, Chang Kyu [Dept. of Radiology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Hur, Bo Yun [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of)

    2015-08-15

    The objective of this study was to evaluate the usefulness of C-arm cone-beam CT (CBCT) in drainage of inaccessible abscesses. To identify the trajectory of the needle or guide wire, CBCT was performed on 21 patients having an inaccessible abscess. CBCT was repeated until proper targeting of the abscess was achieved, before the insertion of a large bore catheter. The etiology, location of the abscess, causes of inaccessibility, radiation dose, technical and clinical success rates of drainage, and any complications confronted, were evaluated. A total of 29 CBCTs were performed for 21 abscesses. Postoperative and non-postoperative abscesses were 9 (42.9%) and 12 (57.1%) in number, respectively. Direct puncture was performed in 18 cases. In 3 cases, the surgical drain or the fistula opening was used as an access route. The causes of inaccessibility were narrow safe window due to adjacent or overlying organs (n = 9), irregularly dispersed abscess (n = 7), deep location with poor sonographic visualization (n = 4), and remote location of the abscess from surgical drain (n = 1). Technical and clinical successes were 95.5% and 100%, respectively. Cumulative air kerma and dose-area product were 21.62 ± 5.41 mGy and 9179.87 ± 2337.70 mGycm2, respectively. There were no procedure related complications. CBCT is a useful technique for identifying the needle and guide wire during drainage of inaccessible abscess.

  14. Dedicated scanner for laboratory investigations on cone-beam CT/SPECT imaging of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Mettivier, Giovanni, E-mail: mettivier@na.infn.i [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, I-80126 Napoli (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy); Russo, Paolo, E-mail: russo@na.infn.i [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, I-80126 Napoli (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy); Cesarelli, Mario; Ospizio, Roberto [Dipartimento di Ingegneria Biomedica, Elettronica e delle Telecomunicazioni, Universita di Napoli Federico II, I-80125 Napoli (Italy); Passeggio, Giuseppe; Roscilli, Lorenzo; Pontoriere, Giuseppe; Rocco, Raffaele [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy)

    2011-02-11

    We describe the design, realization and basic tests of a prototype Cone-Beam Breast Computed Tomography (CBBCT) scanner, combined with a SPECT head consisting of a compact pinhole gamma camera based on a photon counting CdTe hybrid pixel detector. The instrument features a 40 {mu}m focal spot X-ray tube, a 50 {mu}m pitch flat panel detector and a 1-mm-thick, 55 {mu}m pitch CdTe pixel detector. Preliminary imaging tests of the separate CT and gamma-ray units are presented showing a resolution in CT of 3.2 mm{sup -1} at a radial distance of 50 mm from the rotation axis and that the 5 and 8 mm hot masses ({sup 99m}Tc labeled with a 15:1 activity ratio with respect to the background) can be detected in planar gamma-ray imaging with a contrast-to-noise ratio of about 4.

  15. Cone beam computed tomography of plastinated hearts for instruction of radiological anatomy.

    Science.gov (United States)

    Chang, Chih-Wei; Atkinson, Gregory; Gandhi, Niket; Farrell, Michael L; Labrash, Steven; Smith, Alice B; Norton, Neil S; Matsui, Takashi; Lozanoff, Scott

    2016-09-01

    Radiological anatomy education is an important aspect of the medical curriculum. The purpose of this study was to establish and demonstrate the use of plastinated anatomical specimens, specifically human hearts, for use in radiological anatomy education. Four human hearts were processed with routine plastination procedures at room temperature. Specimens were subjected to cone beam computed tomography and a graphics program (ER3D) was applied to generate 3D cardiac models. A comparison was conducted between plastinated hearts and their corresponding computer models based on a list of morphological cardiac features commonly studied in the gross anatomy laboratory. Results showed significant correspondence between plastinations and CBCT-generated 3D models (98 %; p correspondence was achieved between plastinations and 2D CBCT slices. Complete correspondence (100 %) was achieved between key observations on the plastinations and internal radiological findings typically required of medical student. All pathologic features seen on the plastinated hearts were also visualized internally with the CBCT-generated models and 2D slices. These results suggest that CBCT-derived slices and models can be successfully generated from plastinated material and provide accurate representations for radiological anatomy education.

  16. Quantitative analysis of periapical lesions on cone beam computed tomograph and periapical radiograph

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hoa; Lee, Wan; Kim, Kyung Soo; Roh, Young Chea; Lee, Byung Do [Department of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Kim, De Sok [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Deajeon (Korea, Republic of)

    2009-03-15

    To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

  17. Facial soft tissue esthetic predictions: validation in craniomaxillofacial surgery with cone beam computed tomography data.

    Science.gov (United States)

    Bianchi, Alberto; Muyldermans, Louis; Di Martino, Mirko; Lancellotti, Lorenzo; Amadori, Sara; Sarti, Alessandro; Marchetti, Claudio

    2010-07-01

    Facial soft tissue prediction in orthognathic surgery could be a valuable aid to preview the results and determine the best surgical treatment. After many years, considerable difficulties are still present in the prediction of the clinical final aspect. The object of the present study was to validate new soft tissue simulation software (SurgiCase CMF; Materialise, Leuven, Belgium), using data acquired by cone beam computed tomography (CBCT), that makes it possible to foresee the final result. Ten patients with craniomaxillofacial deformations underwent CBCT before surgery. Using the SurgiCase CMF software, the data were reconstructed in 3 dimensions, and various osteotomies were simulated in a 3-dimensional virtual environment by applying different surgical procedures. At 6 months after surgery, the patients underwent repeat CBCT. Thus, it was possible to superimpose the pre- and postoperative CBCT studies to evaluate the reproducibility and reliability of the software. CBCT simulations defined an average absolute error of 0.94 mm, a standard deviation of 0.90 mm, and a percentage of error less than 2 mm of 86.80%. The preliminary results have allowed us to conclude that simulations in orthognathic surgery for skull-maxillofacial deformities using CBCT acquisition are reliable, in addition to the low radiation exposure, and could become the reference standard to plan surgical treatment. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Metal artifact reduction in cone beam computed tomography using forward projected reconstruction information

    Energy Technology Data Exchange (ETDEWEB)

    Meilinger, Manuel [Regensburg Univ. (Germany). CIML Group; Siemens Healthcare, Erlangen (Germany); Schmidgunst, Christian; Schuetz, Oliver [Siemens Healthcare, Erlangen (Germany); Lang, Elmar W. [Regensburg Univ. (Germany). CIML Group

    2011-07-01

    In this work we present a new method to reduce artifacts, produced by high-density objects, especially metal implants, in X-ray cone beam computed tomography (CBCT). These artifacts influence clinical diagnostics and treatments using CT data, if metal objects are located in the field of view (FOV). Our novel method reduces metal artifacts by virtually replacing the metal objects with tissue objects of the same shape. First, the considered objects must be segmented in the original 2D projection data as well as in a reconstructed 3D volume. The attenuation coefficients of the segmented voxels are replaced with adequate attenuation coefficients of tissue (or water), then the required parts of the volume are projected onto the segmented 2D pixels, to replace the original information. This corrected 2D data can then be reconstructed with reduced artifacts, i.e. all metal objects virtually vanished. After the reconstruction, the segmented 3D metal objects were re-inserted into the corrected 3D volume. Our method was developed for mobile C-arm CBCTs; as it is necessary that they are of low weight, the C-arm results in unpredictable distortion. This misalignment between the original 2D data and the forward projection of the reconstructed 3D volume must be adjusted before the correction of the segmented 2D pixels. We applied this technique to clinical data and will now present the results. (orig.)

  19. Hardware-accelerated cone-beam reconstruction on a mobile C-arm

    Science.gov (United States)

    Churchill, Michael; Pope, Gordon; Penman, Jeffrey; Riabkov, Dmitry; Xue, Xinwei; Cheryauka, Arvi

    2007-03-01

    The three-dimensional image reconstruction process used in interventional CT imaging is computationally demanding. Implementation on general-purpose computational platforms requires a substantial time, which is undesirable during time-critical surgical and minimally invasive procedures. Field Programmable Gate Arrays (FPGA)s and Graphics Processing Units (GPU)s have been studied as a platform to accelerate 3-D imaging. FPGA and GPU devices offer a reprogrammable hardware architecture, configurable for pipelining and high levels of parallel processing to increase computational throughput, as well as the benefits of being off-the-shelf and effective 'performance-to-watt' solutions. The main focus of this paper is on the backprojection step of the image reconstruction process, since it is the most computationally intensive part. Using the popular Feldkamp-Davis-Kress (FDK) cone-beam algorithm, our studies indicate the entire 256 3 image reconstruction process can be accelerated to real or near real-time (i.e. immediately after a finished scan of 15-30 seconds duration) on a mobile X-ray C-arm system using available resources on built-in FPGA board. High resolution 512 3 image backprojection can be also accomplished within the same scanning time on a high-end GPU board comprising up to 128 streaming processors.

  20. [Cone-beam CT study of bone septa during maxillary sinus lift among Changzhou population].

    Science.gov (United States)

    Chen, Min-zhen; Xie, Yong-fu; Xie, Hui; Wang, Guo-hai; He, Jia-cai

    2016-02-01

    To observe the incidence, location, morphological characteristics of sinus septa among Changzhou population, and to investigate the relationship between maxillary posterior teeth loss and bony septum, and the guiding significance for sinus lift. One hundred and twenty-four subjects were selected, the preoperative cone-beam CT (CBCT) data was analyzed by NNT software, which provided a three-dimensional measurement of the maxillary sinus septa. SPSS 13.0 software package was used for statistical analysis. 33.87%(42/124)subjects had sinus septa, 27.42%(68/248)sinus had septa. 66.18% (45/68) of the septa were located in the middle region, 22.06% (15/68)in the posterior region, 11.76%(8/68) in the anterior region. The occurrence of sinus septa had no relation with gender, age and loss of teeth. The sinus septa can be observed by CBCT for the position, pattern, to predict the difficulty of the surgery, and enhance the success rate.

  1. Association between Odontogenic Conditions and Maxillary Sinus Disease: A Study Using Cone-beam Computed Tomography.

    Science.gov (United States)

    Nascimento, Eduarda Helena Leandro; Pontual, Maria Luiza A; Pontual, Andrea A; Freitas, Deborah Q; Perez, Danyel E Cruz; Ramos-Perez, Flávia M M

    2016-10-01

    The maxillary sinus can be affected by dental infections because of its close relationship with upper teeth. This study aimed to assess the most common types of maxillary sinus alterations and to associate them with odontogenic conditions using cone-beam computed tomographic (CBCT) images. CBCT scans of 400 patients showing sinus disease in 1 or both maxillary sinuses were evaluated. Sinus alteration was considered as follows: generalized or localized mucosal thickening (MT), maxillary sinusitis (MS), and retention cysts (RCs). The odontogenic conditions evaluated were inadequate endodontic treatment, periapical lesions, and periodontal bone loss. Descriptive and multiple logistic regression analyses were performed. Sinus diseases were observed in 85.9% of the maxillary sinuses. The most prevalent condition was generalized MT (65.2%) followed by localized MT (24.8%), MS (6.4%), and RCs (3.6%). Generalized MT was more related to males (odds ratio = 1.45, P teeth and the sinus floor (odds ratio = 2.77, P sinus diseases were the generalized and localized MT, and they were the only ones related to odontogenic conditions (periodontal bone loss and periapical lesions, respectively). We emphasize that CBCT imaging is an appropriate method for evaluating the maxillary sinus findings and their associated odontogenic conditions. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Maxillary sinus pneumatization after maxillary molar extraction assessed with cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yu Hoa; Nah, Kyung Soo; Cho, Bong Hae [Department of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    2009-09-15

    The purpose of this study was to examine the inferior expansion of the maxillary sinus floor following maxillary molar extraction. Cone beam computed tomographic images of 59 subjects were used to evaluate the height difference of the maxillary sinus floor between extraction sites and contralateral dentate sites. The height of the maxillary sinus floor was defined as the vertical distance to the Frankfort plane from the level of the anterior nasal spine to the most inferior point of the sinus floor. We examined the difference in sinus pneumatization according to the number of missing teeth and the vertical relationship of the molar roots to the sinus floor. The inferior expansion of the maxillary sinus floor was 1.20 {+-} 1.86 mm on the maxillary first molar and 1.90 {+-} 2.42 mm on the maxillary second molar. Increased expansion was observed in cases where two proximate molars were extracted. There was no significant difference in sinus pneumatization following extraction according to the vertical relationship of the molar roots to the sinus floor. The results of this study confirm that sinus pneumatization occurs following maxillary molar extraction. In situations where pneumatization can affect treatment after molar extraction, three-dimensional radiography should be considered.

  3. Cone-beam computed tomography evaluation of Pont's index predictability for Malay population in orthodontics

    Science.gov (United States)

    Alam, Mohammad Khursheed; Shahid, Fazal; Purmal, Kathiravan; Khamis, Mohd Fadhli

    2015-01-01

    Introduction: In orthodontic treatment, three-dimensional (3D) dental casts has a significant role in diagnosis and treatment planning. The aim of this study was to evaluate Pont's index predictability in orthodontics. Materials and Methods: Premolar arch width, molar arch width and mesiodistal width of the maxillary incisors were measured three-dimensionally to assess shape of dental arches. The data source was cone beam computed tomography (CBCT) high volumetric data acquisitions from Malay ethnic background. Arch widths were measured and recorded from 53 subjects (32 male and 21 female with the mean age, 25.81), both the maxillary and mandibular arches, to obtain CBCT high volumetric data. All measurements were obtained through CBCT Planmeca Romexis TM Software 2.3.1.R (Helsinki, Finland). Results: Pont's formula overestimated the upper and lower interpremolar distance, with mean differences of 8.35 ± 3 mm and 12.02 ± 3.20 mm, respectively. Furthermore, the formula overestimated the upper and lower intermolar distance, with mean differences of 7.87 ± 3 mm and 16.14 ± 5.86 mm, respectively. Conclusions: The results indicate that Pont's index is not practical for use with the Malaysian population since the index overestimated interpremolar and intermolar widths. This raises questions whether the index is a true predictor of arch width measurements. PMID:26604597

  4. The current status of cone beam computed tomography imaging in orthodontics

    Science.gov (United States)

    Kapila, S; Conley, R S; Harrell, W E

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations. PMID:21159912

  5. Clinical Implementation Of Megavoltage Cone Beam CT As Part Of An IGRT Program

    Science.gov (United States)

    Gonzalez, Albin; Bauer, Lisa; Kinney, Vicki; Crooks, Cheryl

    2008-03-01

    Knowing where the tumor is at all times during treatment is the next challenge in the field of radiation therapy. This issue has become more important because with treatments such as Intensity Modulated Radiation Therapy (IMRT), healthy tissue is spared by using very tight margins around the tumor. These tight margins leave very small room for patient setup errors. The use of an imaging modality in the treatment room as a way to localize the tumor for patient set up is generally known as "Image Guided Radiation Therapy" or IGRT. This article deals with a form of IGRT known as Megavoltage Cone Beam Computed Tomography (MCBCT) using a Siemens Oncor linear accelerator currently in use at Firelands Regional Medical Center. With MCBCT, we are capable of acquiring CT images right before the treatment of the patient and then use this information to position the patient tumor according to the treatment plan. This article presents the steps followed in order to clinically implement this system, as well as some of the quality assurance tests suggested by the manufacturer and some tests developed in house

  6. Prostate image-guided radiotherapy by megavolt cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Zucca, Sergio; Carau, Barbara; Solla, Ignazio; Garibaldi, Elisabetta; Farace, Paolo; Lay, Giancarlo; Meleddu, Gianfranco; Gabriele, Pietro [Regional Oncological Hospital, Cagliari (Italy). Dept. of Radiooncology

    2011-08-15

    To test megavolt cone-beam CT (MV-CBCT) in order to evaluate setup errors in prostate radiotherapy. The setup of 9 patients was verified weekly by electronic portal imaging (EPI) and MV-CBCT, both performed in the same treatment session. EPI were compared with digitally reconstructed radiographies (DRRs). MV-CBCTs were matched to simulation CTs by manual registration based on bone markers (BMR), by manual registration based on soft tissues (STR) - rectum, bladder, and seminal vesicles - and by automatic registration (AR) performed by a mutual information algorithm. Shifts were evaluated along the three main axes: anteroposterior (AP), craniocaudal (CC), and laterolateral (LL). Finally, in 4 additional patients showing intraprostatic calcifications, the calcification mismatch error was used to evaluate the three MV-CBCT matching methods. A total of 50 pairs of orthogonal EPIs and 50 MV-CBCTs were analyzed. Assuming an overall tolerance of 2 mm, no significant differences were observed comparing EPI vs BMR in any axis. A significant difference (p < 0.001) was observed along the AP axis comparing EPI vs AR and EPI vs STR. On the calcification data set (22 measures), the calcification mismatch along the AP direction was significantly lower (p < 0.05) after STR than after BMR or AR. Bone markers were not an effective surrogate of the target position and significant differences were observed comparing EPI or BMR vs STR, supporting the assessment of soft tissue position by MVCBs to verify and correct patient setup in prostate radiotherapy. (orig.)

  7. Cone-beam micro-CT system based on LabVIEW software.

    Science.gov (United States)

    Ionita, Ciprian N; Hoffmann, Keneth R; Bednarek, Daniel R; Chityala, Ravishankar; Rudin, Stephen

    2008-09-01

    Construction of a cone-beam computed tomography (CBCT) system for laboratory research usually requires integration of different software and hardware components. As a result, building and operating such a complex system require the expertise of researchers with significantly different backgrounds. Additionally, writing flexible code to control the hardware components of a CBCT system combined with designing a friendly graphical user interface (GUI) can be cumbersome and time consuming. An intuitive and flexible program structure, as well as the program GUI for CBCT acquisition, is presented in this note. The program was developed in National Instrument's Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) graphical language and is designed to control a custom-built CBCT system but has been also used in a standard angiographic suite. The hardware components are commercially available to researchers and are in general provided with software drivers which are LabVIEW compatible. The program structure was designed as a sequential chain. Each step in the chain takes care of one or two hardware commands at a time; the execution of the sequence can be modified according to the CBCT system design. We have scanned and reconstructed over 200 specimens using this interface and present three examples which cover different areas of interest encountered in laboratory research. The resulting 3D data are rendered using a commercial workstation. The program described in this paper is available for use or improvement by other researchers.

  8. Evaluation of metal artefact reduction in cone-beam computed tomography images of different dental materials.

    Science.gov (United States)

    Queiroz, Polyane Mazucatto; Oliveira, Matheus Lima; Groppo, Francisco Carlos; Haiter-Neto, Francisco; Freitas, Deborah Queiroz

    2017-05-23

    The aim of this study is to evaluate the efficacy of metal artefact reduction (MAR) in different dental materials with Picasso Trio cone-beam computed tomography (CBCT) scanner. Three imaging phantoms were custom-made of acrylic resin. Each phantom presented three cylinders of the same material: dental amalgam alloy, gutta-percha or aluminium-copper alloy. CBCT scans were performed on Picasso Trio unit with and without MAR, and artefact expression (standard deviation of grey values) was obtained and compared by Kruskal-Wallis and Student-Newman-Keuls (post hoc) (α = 0.05). Significant reduction of artefact expression (p  0.05) was observed with or without MAR when gutta-percha was scanned. MAR was effective in reducing artefacts arising from dental alloys on CBCT images. Dental materials of high atomic number and density are widely used in dentistry and can produce artefact that compromise CBCT image. The present study demonstrated that metal artefact reduction algorithm is an effective tool to improve image quality.

  9. Digital panoramic radiography versus cone beam computed tomography in the delineation of maxillomandibular tumors.

    Science.gov (United States)

    Almeida-Barros, Renata Quirino de; Abilio, Vanessa Maria Freire; Yamamoto, Angela Toshie Araki; Melo, Daniela Pita de; Godoy, Gustavo Pina; Bento, Patricia Meira

    2015-01-01

    This research aimed to compare the efficacy of digital panoramic radiography (DPR) with that of cone beam computed tomography (CBCT) for delineation of odontogenic and nonodontogenic tumors. From November 2009 through March 2011, 23 tumors in the maxillomandibular complex were diagnosed by histopathological examination. All DPRs and CBCTs were obtained and analyzed by a single previously calibrated radiologist, who considered the following radiographic aspects: clarity of the lesion edges, relation with dental elements, involvement of adjacent anatomical structures, cortical bone expansion and disruption, and, if present, type of involved anatomical structures and site of bone expansion and disruption. Of 23 patients, 15 (65.2%) were male and 8 (34.8%) were female. The tumor was classified as odontogenic in 73.9% of patients and nonodontogenic in 26.1% of patients. Analysis revealed that 56.5% of the tumors were located in the mandible, 34.8% in the maxilla, and 8.7% in both arches. For all analyzed variables, CBCTs offered more accurate details than did DPRs. Panoramic radiography should not be the examination of choice to visualize lesions in the maxillomandibular complex.

  10. Quantitative Assessment of Cervical Vertebral Maturation Using Cone Beam Computed Tomography in Korean Girls

    Directory of Open Access Journals (Sweden)

    Bo-Ram Byun

    2015-01-01

    Full Text Available This study was aimed to examine the correlation between skeletal maturation status and parameters from the odontoid process/body of the second vertebra and the bodies of third and fourth cervical vertebrae and simultaneously build multiple regression models to be able to estimate skeletal maturation status in Korean girls. Hand-wrist radiographs and cone beam computed tomography (CBCT images were obtained from 74 Korean girls (6–18 years of age. CBCT-generated cervical vertebral maturation (CVM was used to demarcate the odontoid process and the body of the second cervical vertebra, based on the dentocentral synchondrosis. Correlation coefficient analysis and multiple linear regression analysis were used for each parameter of the cervical vertebrae (P<0.05. Forty-seven of 64 parameters from CBCT-generated CVM (independent variables exhibited statistically significant correlations (P<0.05. The multiple regression model with the greatest R2 had six parameters (PH2/W2, UW2/W2, (OH+AH2/LW2, UW3/LW3, D3, and H4/W4 as independent variables with a variance inflation factor (VIF of <2. CBCT-generated CVM was able to include parameters from the second cervical vertebral body and odontoid process, respectively, for the multiple regression models. This suggests that quantitative analysis might be used to estimate skeletal maturation status.

  11. Accuracy and reliability of stitched cone-beam computed tomography images

    Energy Technology Data Exchange (ETDEWEB)

    Egbert, Nicholas [Private Practice, Reconstructive Dental Specialists of Utah, Salt Lake (United States); Cagna, David R.; Ahuja, Swati; Wicks, Russell A. [Dept. of rosthodontics, University of Tennessee Health Science Center College of Dentistry, Memphis (United States)

    2015-03-15

    This study was performed to evaluate the linear distance accuracy and reliability of stitched small field of view (FOV) cone-beam computed tomography (CBCT) reconstructed images for the fabrication of implant surgical guides. Three gutta percha points were fixed on the inferior border of a cadaveric mandible to serve as control reference points. Ten additional gutta percha points, representing fiduciary markers, were scattered on the buccal and lingual cortices at the level of the proposed complete denture flange. A digital caliper was used to measure the distance between the reference points and fiduciary markers, which represented the anatomic linear dimension. The mandible was scanned using small FOV CBCT, and the images were then reconstructed and stitched using the manufacturer's imaging software. The same measurements were then taken with the CBCT software. The anatomic linear dimension measurements and stitched small FOV CBCT measurements were statistically evaluated for linear accuracy. The mean difference between the anatomic linear dimension measurements and the stitched small FOV CBCT measurements was found to be 0.34 mm with a 95% confidence interval of +0.24 - +0.44 mm and a mean standard deviation of 0.30 mm. The difference between the control and the stitched small FOV CBCT measurements was insignificant within the parameters defined by this study. The proven accuracy of stitched small FOV CBCT data sets may allow image-guided fabrication of implant surgical stents from such data sets.

  12. Does hyrax expansion therapy affect maxillary sinus volume? A cone-beam computed tomography report

    Energy Technology Data Exchange (ETDEWEB)

    Darsey, Drew M.; English, Jeryl D.; Ellis, Randy K.; Akyalcin, Sercan [School of Dentistry, University of Texas Health Science Center at Houston, Houston (United States); Kau, Chung H [School of Dentistry, University of Alabama at Birmingham, Birmingham (United States)

    2012-06-15

    The aim of this study was to investigate the initial effects of maxillary expansion therapy with Hyrax appliance and to evaluate the related changes in maxillary sinus volume. Thirty patients (20 females, 10 males; 13.8 years) requiring maxillary expansion therapy, as part of their comprehensive orthodontic treatment, were examined. Each patient had cone-beam computed tomography (CBCT) images taken before (T1) and after (T2) maxillary expansion therapy with a banded Hyrax appliance. Multiplanar slices were used to measure linear dimensions and palatal vault angle. Volumetric analysis was used to measure maxillary sinus volumes. Student t tests were used to compare the pre- and post-treatment measurements. Additionally, differences between two age groups were compared with Mann-Whitney U test. The level of significance was set at p=0.05. Comparison of pre-treatment to post-treatment variables revealed significant changes in the transverse dimension related to both maxillary skeletal and dental structures and palatal vault angle, resulting in a widened palatal vault (p<0.05). Hard palate showed no significant movement in the vertical and anteroposterior planes. Nasal cavity width increased on a mean value of 0.93 mm(SD=0.23, p<0.05). Maxillary sinus volume remained virtually stable. No significant age differences were observed in the sample. Hyrax expansion therapy did not have a significant impact on maxillary sinus volume.

  13. 3D Quantification of Mandibular Asymmetry through Cone Beam Computed Tomography

    Science.gov (United States)

    Cevidanes, Lucia H.S.; Alhadidi, Abeer; Paniagua, Beatriz; Styner, Martin; Ludlow, John; Mol, Andre; Turvey, Timothy; Proffit, William R.; Rossouw, Paul Emile

    2011-01-01

    Objective To determine if 3D shape analysis precisely diagnoses right and left differences in asymmetry patients Study Design Cone-beam CT data was acquired pretreatment from 20 patients with mandibular asymmetry. 3D shape analysis was used to localize and quantify the extent of virtually simulated asymmetry. Two approaches were used: (1) mirroring on the midsagittal plane determined from landmarks and (2) mirroring on an arbitrary plane, then registering on the cranial base of the original image. The validation presented in this study used simulated data and has been applied to three clinical cases. Results For mirroring on the midsagittal plane there was a >99% probability that the difference between measured and simulated asymmetry was less than 0.5 mm. For mirroring with cranial base registration, there was a >84% probability of differences less than 0.5 mm. Conclusions Mandibular asymmetry can be precisely quantified with both mirroring methods. Cranial base registration has the potential to be used for patients with trauma situations or when key landmarks are unreliable or absent. PMID:21497527

  14. Observer Reliability of Three-Dimensional Cephalometric Landmark Identification on Cone-Beam CT

    Science.gov (United States)

    de Oliveira, Ana Emilia F.; Cevidanes, Lucia Helena S.; Phillips, Ceib; Motta, Alexandre; Burke, Brandon; Tyndall, Donald

    2009-01-01

    Objective To evaluate reliability in 3D landmark identification using Cone-Beam CT. Study Design Twelve pre-surgery CBCTs were randomly selected from 159 orthognathic surgery patients. Three observers independently repeated three times the identification of 30 landmarks in the sagittal, coronal, and axial slices. A mixed effects ANOVA model estimated the Intraclass Correlations (ICC) and assessed systematic bias. Results The ICC was >0.9 for 86% of intra-observer assessments and 66% of inter-observer assessments. Only 1% of intra-observer and 3% of inter-observer coefficients were <0.45. The systematic difference among observers was greater in X and Z than in Y dimensions, but the maximum mean difference was quite small. Conclusion Overall, the intra- and inter-observer reliability was excellent. 3D landmark identification using CBCT can offer consistent and reproducible data, if a protocol for operator training and calibration is followed. This is particularly important for landmarks not easily specified in all three planes of space. PMID:18718796

  15. ANATOMICAL VARIATIONS FINDINGS ON CONE BEAM-COMPUTED TOMOGRAPHY IN CLEFT LIP AND PALATE PATIENTS

    Directory of Open Access Journals (Sweden)

    Yllka DECOLLI

    2015-09-01

    Full Text Available Introduction: Cone beam computed tomography (CBCT is frequently used in surgery treatment planning in patients with cleft lip and palate (CLP. The aim of this study was to investigate the presence of different anatomical variations of patients with cleft lip and palate using CBCT images. Materials and method: CBCTs taken from consecutive patients (n =25; mean age 10.7±4 years, range 6.5–23 years with a non-syndromic cleft lip and palate (CLP, between June 2014-2015, were systematically evaluated. Sinuses, nasopharynx, oropharynx, hypopharynx, temporo-mandibular joint (TMJ, maxilla and mandible were checked for incidental findings. Results: On 90.1 % of the CBCTs, incidental findings were found. The most prevalent ones were airway/sinus findings (78.1%, followed by dental problems, e.g. missing teeth (54%, nasal septum deviation (93%, middle ear and mastoid opacification, suggestive for otitis media (8% and (chronic mastoiditis (7%, abnormal TMJ anatomy (4.3%. Conclusions: Incidental findings are common on CBCTs in cleft lip and palate patients. Compared with the literature, CLP patients have more dental, nasal and ear problems. The CBCT scan should be reviewed by all specialists in the CLP team, stress being laid on their specific background knowledge concerning symptoms and treatment of these patients.

  16. High-resolution-cone beam tomography analysis of bone microarchitecture in patients with acromegaly and radiological vertebral fractures.

    Science.gov (United States)

    Maffezzoni, Filippo; Maddalo, Michele; Frara, Stefano; Mezzone, Monica; Zorza, Ivan; Baruffaldi, Fabio; Doglietto, Francesco; Mazziotti, Gherardo; Maroldi, Roberto; Giustina, Andrea

    2016-11-01

    Vertebral fractures are an emerging complication of acromegaly but their prediction is still difficult occurring even in patients with normal bone mineral density. In this study we evaluated the ability of high-resolution cone-beam computed tomography to provide information on skeletal abnormalities associated with vertebral fractures in acromegaly. 40 patients (24 females, 16 males; median age 57 years, range 25-72) and 21 healthy volunteers (10 females, 11 males; median age 60 years, range: 25-68) were evaluated for trabecular (bone volume/trabecular volume ratio, mean trabecular separation, and mean trabecular thickness) and cortical (thickness and porosity) parameters at distal radius using a high-resolution cone-beam computed tomography system. All acromegaly patients were evaluated for morphometric vertebral fractures and for mineral bone density by dual-energy X-ray absorptiometry at lumbar spine, total hip, femoral neck, and distal radius. Acromegaly patients with vertebral fractures (15 cases) had significantly (p cone-beam computed tomography at the distal radius may be useful to evaluate and predict the effects of acromegaly on bone microstructure.

  17. Evaluation of the potential of automatic segmentation of the mandibular canal using cone-beam computed tomography.

    Science.gov (United States)

    Gerlach, Nicolaas Lucius; Meijer, Gerrit Jacobus; Kroon, Dirk-Jan; Bronkhorst, Ewald Maria; Bergé, Stefaan Jozef; Maal, Thomas Jan Jaap

    2014-11-01

    We aimed to investigate the effectiveness of software for automatically tracing the mandibular canal on data from cone-beam computed tomography (CT). After the data had been collected from one dentate and one edentate fresh cadaver head, both a trained Active Shape Model (ASM) and an Active Appearance Model (AAM) were used to automatically segment the canals from the mandibular to the mental foramen. Semiautomatic segmentation was also evaluated by providing the models with manual annotations of the foramina. To find out if the tracings were in accordance with the actual anatomy, we compared the position of the automatic mandibular canal segmentations, as displayed on cross-sectional cone-beam CT views, with histological sections of exactly the same region. The significance of differences between results were analysed with the help of Fisher's exact test and Pearson's correlation coefficient. When tracings based on AAM and ASM were used, differences between cone-beam CT and histological measurements varied up to 3.45mm and 4.44mm, respectively. Manual marking of the mandibular and mental foramina did not improve the results, and there were no significant differences (p=0.097) among the methods. The accuracy of automatic segmentation of the mandibular canal by the AAM and ASM methods is inadequate for use in clinical practice.

  18. Cone-Beam Composite-Circling Scan and Exact Image Reconstruction for a Quasi-Short Object

    Directory of Open Access Journals (Sweden)

    Hengyong Yu

    2007-01-01

    Full Text Available Here we propose a cone-beam composite-circling mode to solve the quasi-short object problem, which is to reconstruct a short portion of a long object from longitudinally truncated cone-beam data involving the short object. In contrast to the saddle curve cone-beam scanning, the proposed scanning mode requires that the X-ray focal spot undergoes a circular motion in a plane facing the short object, while the X-ray source is rotated in the gantry main plane. Because of the symmetry of the proposed mechanical rotations and the compatibility with the physiological conditions, this new mode has significant advantages over the saddle curve from perspectives of both engineering implementation and clinical applications. As a feasibility study, a backprojection filtration (BPF algorithm is developed to reconstruct images from data collected along a composite-circling trajectory. The initial simulation results demonstrate the correctness of the proposed exact reconstruction method and the merits of the proposed mode.

  19. C-arm based cone-beam CT using a two-concentric-arc source trajectory: system evaluation

    Science.gov (United States)

    Zambelli, Joseph; Zhuang, Tingliang; Nett, Brian E.; Riddell, Cyril; Belanger, Barry; Chen, Guang-Hong

    2008-03-01

    The current x-ray source trajectory for C-arm based cone-beam CT is a single arc. Reconstruction from data acquired with this trajectory yields cone-beam artifacts for regions other than the central slice. In this work we present the preliminary evaluation of reconstruction from a source trajectory of two concentric arcs using a flat-panel detector equipped C-arm gantry (GE Healthcare Innova 4100 system, Waukesha, Wisconsin). The reconstruction method employed is a summation of FDK-type reconstructions from the two individual arcs. For the angle between arcs studied here, 30°, this method offers a significant reduction in the visibility of cone-beam artifacts, with the additional advantages of simplicity and ease of implementation due to the fact that it is a direct extension of the reconstruction method currently implemented on commercial systems. Reconstructed images from data acquired from the two arc trajectory are compared to those reconstructed from a single arc trajectory and evaluated in terms of spatial resolution, low contrast resolution, noise, and artifact level.

  20. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging.

    Science.gov (United States)

    Anas, Emran Mohammad Abu; Kim, Jae Gon; Lee, Soo Yeol; Hasan, Md Kamrul

    2011-10-07

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  1. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul [Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Kim, Jae Gon; Lee, Soo Yeol, E-mail: khasan@eee.buet.ac.b [Department of Biomedical Engineering, Kyung Hee University, Kyungki 446-701 (Korea, Republic of)

    2011-10-07

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  2. Determination and verification of a 2D pencil-beam kernel for a radiosurgery system with cones.

    Science.gov (United States)

    Vargas-Verdesoto, Milton Xavier; Álvarez-Romero, José Trinidad

    2013-01-01

    The quality and correctness of dosimetric data of small fields in stereotactic radiosurgery (SRS) depends significantly on the election of the detector employed in the measurements. This work provides an independent method of verification of these data through the determination of a polyenergetic 2-dimensional pencil-beam kernel for a BrainLAB SRS system with cones, employing the deconvolution/convolution of a reference experimental off-axis ratio (OAR) profile (cone diameter c0 = 35 mm). The kernel in real space k(c(0))(r,z(0)) is convolved with the ideal fluence Φ for the cones 7.5 to 35 mm in diameter to obtain the OAR profiles, and the total scatter factors, St, which are compared with experimental values of the same quantities. The experimental OARs and St factors are measured in water with a PTW 60003 diamond detector. Additionally, the reference OAR is corrected for beam divergence and spectral fluence fluctuations defining a function of boundary correction factors (BF). The BF and Φ functions are transformed to the conjugate space with the zeroth-order Hankel transform, appropriated to the radial symmetry of the cones. Therefore, the kernel in real space k(c(0))(r,z(0)) is the inverse Hankel transform of the ratio of the Hankel transforms of BF and Φ. Finally, an uncertainty analysis according to the Guide to the Expression of Uncertainty in Measurement is carried out for 3 different values of k(c(0))(r,z(0)). Calculated and measured OARs agree within the dose/distance-to-agreement criteria of 2%/0.12 mm; while, St factors agree within 2%. This procedure supplies an independent method to validate the dosimetric data necessary to feed treatment planning systems for SRS with cones.

  3. Determination and verification of a 2D pencil-beam kernel for a radiosurgery system with cones

    Energy Technology Data Exchange (ETDEWEB)

    Vargas-Verdesoto, Milton Xavier, E-mail: mxvv2003@hotmail.com [Centro Oncológico de Chihuahua, Hacienda de la Esperanza, Chihuahua, México (Mexico); Universidad Autónoma del Estado de México, Paseo Tollocan, Toluca, Edo. De México, México (Mexico); Álvarez-Romero, José Trinidad [SSDL, Instituto Nacional de Invesigaciones Nucleares, La Marquesa, Ocoyoacac, México (Mexico)

    2013-07-01

    The quality and correctness of dosimetric data of small fields in stereotactic radiosurgery (SRS) depends significantly on the election of the detector employed in the measurements. This work provides an independent method of verification of these data through the determination of a polyenergetic 2-dimensional pencil-beam kernel for a BrainLAB SRS system with cones, employing the deconvolution/convolution of a reference experimental off-axis ratio (OAR) profile (cone diameter c{sub 0} = 35 mm). The kernel in real space k{sub c{sub 0}}(r,z{sub 0}) is convolved with the ideal fluence Φ for the cones 7.5 to 35 mm in diameter to obtain the OAR profiles, and the total scatter factors, S{sub t}, which are compared with experimental values of the same quantities. The experimental OARs and S{sub t} factors are measured in water with a PTW 60003 diamond detector. Additionally, the reference OAR is corrected for beam divergence and spectral fluence fluctuations defining a function of boundary correction factors (BF). The BF and Φ functions are transformed to the conjugate space with the zeroth-order Hankel transform, appropriated to the radial symmetry of the cones. Therefore, the kernel in real space k{sub c{sub 0}}(r,z{sub 0}) is the inverse Hankel transform of the ratio of the Hankel transforms of BF and Φ. Finally, an uncertainty analysis according to the Guide to the Expression of Uncertainty in Measurement is carried out for 3 different values of k{sub c{sub 0}}(r,z{sub 0}). Calculated and measured OARs agree within the dose/distance-to-agreement criteria of 2%/0.12 mm; while, S{sub t} factors agree within 2%. This procedure supplies an independent method to validate the dosimetric data necessary to feed treatment planning systems for SRS with cones.

  4. High-fidelity artifact correction for cone-beam CT imaging of the brain

    Science.gov (United States)

    Sisniega, A.; Zbijewski, W.; Xu, J.; Dang, H.; Stayman, J. W.; Yorkston, J.; Aygun, N.; Koliatsos, V.; Siewerdsen, J. H.

    2015-02-01

    CT is the frontline imaging modality for diagnosis of acute traumatic brain injury (TBI), involving the detection of fresh blood in the brain (contrast of 30-50 HU, detail size down to 1 mm) in a non-contrast-enhanced exam. A dedicated point-of-care imaging system based on cone-beam CT (CBCT) could benefit early detection of TBI and improve direction to appropriate therapy. However, flat-panel detector (FPD) CBCT is challenged by artifacts that degrade contrast resolution and limit application in soft-tissue imaging. We present and evaluate a fairly comprehensive framework for artifact correction to enable soft-tissue brain imaging with FPD CBCT. The framework includes a fast Monte Carlo (MC)-based scatter estimation method complemented by corrections for detector lag, veiling glare, and beam hardening. The fast MC scatter estimation combines GPU acceleration, variance reduction, and simulation with a low number of photon histories and reduced number of projection angles (sparse MC) augmented by kernel de-noising to yield a runtime of ~4 min per scan. Scatter correction is combined with two-pass beam hardening correction. Detector lag correction is based on temporal deconvolution of the measured lag response function. The effects of detector veiling glare are reduced by deconvolution of the glare response function representing the long range tails of the detector point-spread function. The performance of the correction framework is quantified in experiments using a realistic head phantom on a testbench for FPD CBCT. Uncorrected reconstructions were non-diagnostic for soft-tissue imaging tasks in the brain. After processing with the artifact correction framework, image uniformity was substantially improved, and artifacts were reduced to a level that enabled visualization of ~3 mm simulated bleeds throughout the brain. Non-uniformity (cupping) was reduced by a factor of 5, and contrast of simulated bleeds was improved from ~7 to 49.7 HU, in good agreement

  5. Beam hardening artifacts by dental implants: Comparison of cone-beam and 64-slice computed tomography scanners

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2013-01-01

    Full Text Available Background: Cone beam computed tomography (CBCT is an alternative to a computed tomography (CT scan, which is appropriate for a wide range of craniomaxillofacial indications. The long-term use of metallic materials in dentistry means that artifacts caused by metallic restorations in the oral cavity should be taken into account when utilizing CBCT and CT scanners. The aim of this study was to quantitatively compare the beam hardening artifacts produced by dental implants between CBCT and a 64-Slice CT scanner. Materials and Methods: In this descriptive study , an implant drilling model similar to the human mandible was used in the present study. The implants (Dentis were placed in the canine, premolar and molar areas. Three series of scans were provided from the implant areas using Somatom Sensation 64-slice and NewTom VGi (CBCT CT scanners. Identical images were evaluated by three radiologists. The artifacts in each image were determined based on pre-determined criteria. Kruskal-Wallis test was used to compare mean values; Mann-Whitney U test was used for two-by-two comparisons when there was a statistical significance ( P < 0.05. Results: The images of the two scanners had similar resolutions in axial sections ( P = 0.299. In coronal sections, there were significant differences in the resolutions of the images produced by the two scanners ( P < 0.001, with a higher resolution in the images produced by NewTom VGi scanner. On the whole, there were significant differences between the resolutions of the images produced by the two CT scanners ( P < 0.001, with higher resolution in the images produced by NewTom VGi scanner in comparison to those of Somatom Sensation. Conclusion: Given the high quality of the images produced by NewTom VGi and the lower costs in comparison to CT, the use of the images of this scanner in dental procedures is recommended, especially in patients with extensive restorations, multiple prostheses and previous implants.

  6. TU-EF-207-05: Dedicated Cone-beam Breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, S. [Univ. of Massachusetts Medical School (United States)

    2015-06-15

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation.

  7. Diagnostic accuracy of cone beam computed tomography in detection of simulated mandibular condyle erosions

    Directory of Open Access Journals (Sweden)

    Shahriar Shahab

    2015-01-01

    Full Text Available Introduction: To determine the diagnostic accuracy of cone beam computed tomography (CBCT in the detection of simulated mandibular condyle erosions. Materials and Methods: Seventeen dry human mandibles were used in this in vitro study. NewTom VG CBCT scanner (New Tom VG, Verona, Veneto region, Italy was used for the condyles imaging (pre-erosion and post-erosion image. Thirty three lesions were created on the superior (11 cases, anterior (11 cases, and posterior surfaces (11 cases of the condyles. The pre- and post-erosion images were randomly presented to two previously calibrated oral and maxillofacial radiologists in order to evaluate the presence of simulated erosions and their position in the condyles using two protocols. In the first protocol, axial and coronal images and in the second protocol, axial, coronal, and sagittal/multiplanar reconstructed (MPR images were used to evaluate the lesions of the samples. Furthermore, the Cochran′s Q test and McNemar and Kappa statistical tests were used to assess the sensitivity, specificity, and accuracy of this study. Results: There was no statistically significant difference between the diagnostic methods and the reference value. There was substantial agreement between the two protocols (Kappa > 0.61. Protocol 2 showed relatively better results than protocol 1 but the difference was not statistically significant (P > 0.05. Sensitivity, specificity, and diagnostic accuracy levels in the erosion imaging were higher in the posterior region of condyle; however, there was no statistically significant difference between the condylar regions (P > 0.05. Conclusion: CBCT had high sensitivity, specificity, and diagnostic accuracy in the detection of simulated mandibular condyle erosions.

  8. Automatic intrinsic cardiac and respiratory gating from cone-beam CT scans of the thorax region

    Science.gov (United States)

    Hahn, Andreas; Sauppe, Sebastian; Lell, Michael; Kachelrieß, Marc

    2016-03-01

    We present a new algorithm that allows for raw data-based automated cardiac and respiratory intrinsic gating in cone-beam CT scans. It can be summarized in three steps: First, a median filter is applied to an initially reconstructed volume. The forward projection of this volume contains less motion information and is subtracted from the original projections. This results in new raw data that contain only moving and not static anatomy like bones, that would otherwise impede the cardiac or respiratory signal acquisition. All further steps are applied to these modified raw data. Second, the raw data are cropped to a region of interest (ROI). The ROI in the raw data is determined by the forward projection of a binary volume of interest (VOI) that includes the diaphragm for respiratory gating and most of the edge of the heart for cardiac gating. Third, the mean gray value in this ROI is calculated for every projection and the respiratory/cardiac signal is acquired using a bandpass filter. Steps two and three are carried out simultaneously for 64 or 1440 overlapping VOI inside the body for the respiratory or cardiac signal respectively. The signals acquired from each ROI are compared and the most consistent one is chosen as the desired cardiac or respiratory motion signal. Consistency is assessed by the standard deviation of the time between two maxima. The robustness and efficiency of the method is evaluated using simulated and measured patient data by computing the standard deviation of the mean signal difference between the ground truth and the intrinsic signal.

  9. Incidental findings from a retrospective study of 318 cone beam computed tomography consultation reports.

    Science.gov (United States)

    Pette, Gregory A; Norkin, Frederic J; Ganeles, Jeffrey; Hardigan, Patrick; Lask, Enrique; Zfaz, Samuel; Parker, William

    2012-01-01

    Cone beam computed tomography (CBCT) is a three-dimensional radiographic technique used in planning implant therapy to help clinicians determine the volume and dimension of bone available for implant placement, and CBCT images potentially depict coincident findings. Three hundred eighteen patients received CBCT scans prior to receiving implants, which were interpreted by blinded board-certified oral and maxillofacial radiologists. All incidental findings were defined as non-tooth-related pathologies or abnormalities. These findings were categorized and analyzed using descriptive statistics. The patients ranged in age from 16 to 91 years (mean age for men, 64.73 ± 15.05 years; for women, 62.47 ± 15.83 years). Controlling for age, men were 2.13 times more likely to have sinus pathology than women. Patients over age 65 were 5.01 times more likely to demonstrate vascular pathology (eg, carotid artery calcification) than patients ages 41 to 65; the likelihood versus patients ages 16 to 40 was 13.39. Women were 2.63 times more likely to display brain pathology (eg, pineal or pituitary calcifications). Controlling for gender, patients ages 41 to 65 were 3.17 times more likely to exhibit condylar pathology (eg, degenerative changes) than patients ages 16 to 40. Similarly, patients above age 65 were 3.53 times more likely to show condylar pathology than patients ages 16 to 40, and women were 1.61 times more likely to have condylar pathology than men. Versus patients ages 16 to 40, patients ages 41 to 65 were 17.69 times more likely to show signs of vertebral pathology (eg, degenerative disc changes) and patients over age 65 were 28.67 times more likely to display vertebral pathology. CBCT scans frequently reveal non-tooth-related pathologies and/or abnormalities in the head and neck region. Therefore, comprehensive review of the entire CBCT image set is necessary.

  10. Pediatric Percutaneous Osteoid Osteoma Ablation: Cone-Beam CT with Fluoroscopic Overlay Versus Conventional CT Guidance.

    Science.gov (United States)

    Perry, Brandon C; Monroe, Eric J; McKay, Tyler; Kanal, Kalpana M; Shivaram, Giridhar

    2017-05-11

    To compare technical success, clinical success, complications, radiation dose, and total room utilization time for osteoid osteoma thermal (radiofrequency or microwave) ablation using cone-beam computed tomography (CBCT) with two-axis fluoroscopic navigational overlay versus conventional computed tomography (CT) guidance. A retrospective review was performed to identify all osteoid osteoma ablations performed over a 5.5-year period at a single tertiary care pediatric hospital. Twenty-five ablations (15 radiofrequency and 10 microwave) in 23 patients undergoing fluoroscopic CBCT-guided osteoid osteoma ablation were compared to 35 ablations (35 radiofrequency) in 32 patients undergoing ablation via conventional CT guidance. Dose area product and dose length product were recorded for CBCT and conventional CT, respectively, and converted to effective doses. Technical success, clinical success (cessation of pain and medication use 1 month after ablation), complications, radiation dose, and total room utilization time were compared. All procedures were technically successful. Twenty-two of 25 (88.0%) CBCT and 31 of 35 (88.6%) conventional CT-guided ablations achieved immediate clinical success. There were two minor complications in each group and no major complications. Mean effective radiation dose was significantly lower for CBCT compared to CT guidance (0.12 vs. 0.39 mSv, p = 0.02). Mean total room utilization time for CBCT was longer (133.5 vs. 97.5 min, p = 0.0001). Fluoroscopic CBCT guidance for percutaneous osteoid osteoma ablation yields similar technical and clinical success, reduced radiation dose, and increased total room utilization time compared to conventional CT guidance.

  11. Use of cone beam computed tomography in identifying postmenopausal women with osteoporosis.

    Science.gov (United States)

    Brasileiro, C B; Chalub, L L F H; Abreu, M H N G; Barreiros, I D; Amaral, T M P; Kakehasi, A M; Mesquita, R A

    2017-12-01

    The aim of this study is to correlate radiometric indices from cone beam computed tomography (CBCT) images and bone mineral density (BMD) in postmenopausal women. Quantitative CBCT indices can be used to screen for women with low BMD. Osteoporosis is a disease characterized by the deterioration of bone tissue and the consequent decrease in BMD and increase in bone fragility. Several studies have been performed to assess radiometric indices in panoramic images as low-BMD predictors. The aim of this study is to correlate radiometric indices from CBCT images and BMD in postmenopausal women. Sixty postmenopausal women with indications for dental implants and CBCT evaluation were selected. Dual-energy X-ray absorptiometry (DXA) was performed, and the patients were divided into normal, osteopenia, and osteoporosis groups, according to the World Health Organization (WHO) criteria. Cross-sectional images were used to evaluate the computed tomography mandibular index (CTMI), the computed tomography index (inferior) (CTI (I)) and computed tomography index (superior) (CTI (S)). Student's t test was used to compare the differences between the indices of the groups' intraclass correlation coefficient (ICC). Statistical analysis showed a high degree of interobserver and intraobserver agreement for all measurements (ICC > 0.80). The mean values of CTMI, CTI (S), and CTI (I) were lower in the osteoporosis group than in osteopenia and normal patients (p < 0.05). In comparing normal patients and women with osteopenia, there was no statistically significant difference in the mean value of CTI (I) (p = 0.075). Quantitative CBCT indices may help dentists to screen for women with low spinal and femoral bone mineral density so that they can refer postmenopausal women for bone densitometry.

  12. Volume-of-change cone-beam CT for image-guided surgery

    Science.gov (United States)

    Lee, Junghoon; Webster Stayman, J.; Otake, Yoshito; Schafer, Sebastian; Zbijewski, Wojciech; Khanna, A. Jay; Prince, Jerry L.; Siewerdsen, Jeffrey H.

    2012-08-01

    C-arm cone-beam CT (CBCT) can provide intraoperative 3D imaging capability for surgical guidance, but workflow and radiation dose are the significant barriers to broad utilization. One main reason is that each 3D image acquisition requires a complete scan with a full radiation dose to present a completely new 3D image every time. In this paper, we propose to utilize patient-specific CT or CBCT as prior knowledge to accurately reconstruct the aspects of the region that have changed by the surgical procedure from only a sparse set of x-rays. The proposed methods consist of a 3D-2D registration between the prior volume and a sparse set of intraoperative x-rays, creating digitally reconstructed radiographs (DRRs) from the registered prior volume, computing difference images by subtracting DRRs from the intraoperative x-rays, a penalized likelihood reconstruction of the volume of change (VOC) from the difference images, and finally a fusion of VOC reconstruction with the prior volume to visualize the entire surgical field. When the surgical changes are local and relatively small, the VOC reconstruction involves only a small volume size and a small number of projections, allowing less computation and lower radiation dose than is needed to reconstruct the entire surgical field. We applied this approach to sacroplasty phantom data obtained from a CBCT test bench and vertebroplasty data with a fresh cadaver acquired from a C-arm CBCT system with a flat-panel detector. The VOCs were reconstructed from a varying number of images (10-66 images) and compared to the CBCT ground truth using four different metrics (mean squared error, correlation coefficient, structural similarity index and perceptual difference model). The results show promising reconstruction quality with structural similarity to the ground truth close to 1 even when only 15-20 images were used, allowing dose reduction by the factor of 10-20.

  13. Osteoporosis prediction from the mandible using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Barngkgei, Imad; Al Haffar, Iyad [Dept. of Oral Medicine, Faculty of Dentistry, Damascus University, Damascus (Syrian Arab Republic); Khattab, Razan [Dept. of Periodontology, Faculty of Dentistry, Damascus University, Damascus (Syrian Arab Republic)

    2014-12-15

    This study aimed to evaluate the use of dental cone-beam computed tomography (CBCT) in the diagnosis of osteoporosis among menopausal and postmenopausal women by using only a CBCT viewer program. Thirty-eight menopausal and postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) examination for hip and lumbar vertebrae were scanned using CBCT (field of view: 13 cmx15 cm; voxel size: 0.25 mm). Slices from the body of the mandible as well as the ramus were selected and some CBCT-derived variables, such as radiographic density (RD) as gray values, were calculated as gray values. Pearson's correlation, one-way analysis of variance (ANOVA), and accuracy (sensitivity and specificity) evaluation based on linear and logistic regression were performed to choose the variable that best correlated with the lumbar and femoral neck T-scores. RD of the whole bone area of the mandible was the variable that best correlated with and predicted both the femoral neck and the lumbar vertebrae T-scores; further, Pearson's correlation coefficients were 0.5/0.6 (p value=0.037/0.009). The sensitivity, specificity, and accuracy based on the logistic regression were 50%, 88.9%, and 78.4%, respectively, for the femoral neck, and 46.2%, 91.3%, and 75%, respectively, for the lumbar vertebrae. Lumbar vertebrae and femoral neck osteoporosis can be predicted with high accuracy from the RD value of the body of the mandible by using a CBCT viewer program.

  14. Deformable registration of CT and cone-beam CT with local intensity matching

    Science.gov (United States)

    Park, Seyoun; Plishker, William; Quon, Harry; Wong, John; Shekhar, Raj; Lee, Junghoon

    2017-02-01

    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. In this paper, we propose a method to accurately register CT and CBCT by iteratively matching local CT and CBCT intensities. We correct CBCT intensities by matching local intensity histograms slice by slice in conjunction with intensity-based deformable registration. The correction-registration steps are repeated in an alternating way until the result image converges. We integrate the intensity matching into three different deformable registration methods, B-spline, demons, and optical flow that are widely used for CT-CBCT registration. All three registration methods were implemented on a graphics processing unit for efficient parallel computation. We tested the proposed methods on twenty five head and neck cancer cases and compared the performance with state-of-the-art registration methods. Normalized cross correlation (NCC), structural similarity index (SSIM), and target registration error (TRE) were computed to evaluate the registration performance. Our method produced overall NCC of 0.96, SSIM of 0.94, and TRE of 2.26 → 2.27 mm, outperforming existing methods by 9%, 12%, and 27%, respectively. Experimental results also show that our method performs consistently and is more accurate than existing algorithms, and also computationally efficient.

  15. Motion-aware temporal regularization for improved 4D cone-beam computed tomography

    Science.gov (United States)

    Mory, Cyril; Janssens, Guillaume; Rit, Simon

    2016-09-01

    Four-dimensional cone-beam computed tomography (4D-CBCT) of the free-breathing thorax is a valuable tool in image-guided radiation therapy of the thorax and the upper abdomen. It allows the determination of the position of a tumor throughout the breathing cycle, while only its mean position can be extracted from three-dimensional CBCT. The classical approaches are not fully satisfactory: respiration-correlated methods allow one to accurately locate high-contrast structures in any frame, but contain strong streak artifacts unless the acquisition is significantly slowed down. Motion-compensated methods can yield streak-free, but static, reconstructions. This work proposes a 4D-CBCT method that can be seen as a trade-off between respiration-correlated and motion-compensated reconstruction. It builds upon the existing reconstruction using spatial and temporal regularization (ROOSTER) and is called motion-aware ROOSTER (MA-ROOSTER). It performs temporal regularization along curved trajectories, following the motion estimated on a prior 4D CT scan. MA-ROOSTER does not involve motion-compensated forward and back projections: the input motion is used only during temporal regularization. MA-ROOSTER is compared to ROOSTER, motion-compensated Feldkamp-Davis-Kress (MC-FDK), and two respiration-correlated methods, on CBCT acquisitions of one physical phantom and two patients. It yields streak-free reconstructions, visually similar to MC-FDK, and robust information on tumor location throughout the breathing cycle. MA-ROOSTER also allows a variation of the lung tissue density during the breathing cycle, similar to that of planning CT, which is required for quantitative post-processing.

  16. Radiological Protection in Cone Beam Computed Tomography (CBCT). ICRP Publication 129.

    Science.gov (United States)

    Rehani, M M; Gupta, R; Bartling, S; Sharp, G C; Pauwels, R; Berris, T; Boone, J M

    2015-07-01

    The objective of this publication is to provide guidance on radiological protection in the new technology of cone beam computed tomography (CBCT). Publications 87 and 102 dealt with patient dose management in computed tomography (CT) and multi-detector CT. The new applications of CBCT and the associated radiological protection issues are substantially different from those of conventional CT. The perception that CBCT involves lower doses was only true in initial applications. CBCT is now used widely by specialists who have little or no training in radiological protection. This publication provides recommendations on radiation dose management directed at different stakeholders, and covers principles of radiological protection, training, and quality assurance aspects. Advice on appropriate use of CBCT needs to be made widely available. Advice on optimisation of protection when using CBCT equipment needs to be strengthened, particularly with respect to the use of newer features of the equipment. Manufacturers should standardise radiation dose displays on CBCT equipment to assist users in optimisation of protection and comparisons of performance. Additional challenges to radiological protection are introduced when CBCT-capable equipment is used for both fluoroscopy and tomography during the same procedure. Standardised methods need to be established for tracking and reporting of patient radiation doses from these procedures. The recommendations provided in this publication may evolve in the future as CBCT equipment and applications evolve. As with previous ICRP publications, the Commission hopes that imaging professionals, medical physicists, and manufacturers will use the guidelines and recommendations provided in this publication for implementation of the Commission's principle of optimisation of protection of patients and medical workers, with the objective of keeping exposures as low as reasonably achievable, taking into account economic and societal factors, and

  17. Regularization design for high-quality cone-beam CT of intracranial hemorrhage using statistical reconstruction

    Science.gov (United States)

    Dang, H.; Stayman, J. W.; Xu, J.; Sisniega, A.; Zbijewski, W.; Wang, X.; Foos, D. H.; Aygun, N.; Koliatsos, V. E.; Siewerdsen, J. H.

    2016-03-01

    Intracranial hemorrhage (ICH) is associated with pathologies such as hemorrhagic stroke and traumatic brain injury. Multi-detector CT is the current front-line imaging modality for detecting ICH (fresh blood contrast 40-80 HU, down to 1 mm). Flat-panel detector (FPD) cone-beam CT (CBCT) offers a potential alternative with a smaller scanner footprint, greater portability, and lower cost potentially well suited to deployment at the point of care outside standard diagnostic radiology and emergency room settings. Previous studies have suggested reliable detection of ICH down to 3 mm in CBCT using high-fidelity artifact correction and penalized weighted least-squared (PWLS) image reconstruction with a post-artifact-correction noise model. However, ICH reconstructed by traditional image regularization exhibits nonuniform spatial resolution and noise due to interaction between the statistical weights and regularization, which potentially degrades the detectability of ICH. In this work, we propose three regularization methods designed to overcome these challenges. The first two compute spatially varying certainty for uniform spatial resolution and noise, respectively. The third computes spatially varying regularization strength to achieve uniform "detectability," combining both spatial resolution and noise in a manner analogous to a delta-function detection task. Experiments were conducted on a CBCT test-bench, and image quality was evaluated for simulated ICH in different regions of an anthropomorphic head. The first two methods improved the uniformity in spatial resolution and noise compared to traditional regularization. The third exhibited the highest uniformity in detectability among all methods and best overall image quality. The proposed regularization provides a valuable means to achieve uniform image quality in CBCT of ICH and is being incorporated in a CBCT prototype for ICH imaging.

  18. SU-E-I-11: A New Cone-Beam CT System for Bedside Head Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sun, H; Zeng, W; Xu, P; Wang, Z; Xing, X; Sun, M [Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Jiangsu (China)

    2015-06-15

    Purpose: To design and develop a new mobile cone-beam CT (CBCT) system for head imaging with good soft-tissue visibility, to be used bedside in ICU and neurosurgery department to monitor treatment and operation outcome in brain patients. Methods: The imaging chain consists of a 30cmx25cm amorphous silicon flat panel detector and a pulsed, stationary anode monoblock x-ray source of 100kVp at a maximal tube current of 10mA. The detector and source are supported on motorized mechanisms to provide detector lateral shift and source angular tilt, enabling a centered digital radiographic imaging mode and half-fan CBCT, while maximizing the use of the x-ray field and keep the source to detector distance short. A focused linear anti-scatter grid is mounted on the detector, and commercial software with scatter and other corrective algorithms is used for data processing and image reconstruction. The gantry rotates around a horizontal axis, and is able to adjust its height for different patient table positions. Cables are routed through a custom protective sleeve over a large bore with an in-plane twister band, facilitating single 360-degree rotation without a slip-ring at a speed up to 5 seconds per rotation. A UPS provides about 10 minutes of operation off the battery when unplugged. The gantry is on locked casters, whose brake is control by two push handles on both sides for easy reposition. The entire system is designed to have a light weight and a compact size for excellent maneuverability. Results: System design is complete and main imaging components are tested. Initial results will be presented and discussed later in the presentation. Conclusion: A new mobile CBCT system for head imaging is being developed. With its compact size, a large bore, and quality design, it is expected to be a useful imaging tool for bedside uses. The work is supported by a grant from Chinese Academy of Sciences.

  19. Image-based motion compensation for high-resolution extremities cone-beam CT

    Science.gov (United States)

    Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2016-03-01

    Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

  20. Cone-Beam Computed Tomography (CBCT) Versus CT in Lung Ablation Procedure: Which is Faster?

    Energy Technology Data Exchange (ETDEWEB)

    Cazzato, Roberto Luigi, E-mail: r.cazzato@unicampus.it; Battistuzzi, Jean-Benoit, E-mail: j.battistuzzi@bordeaux.unicancer.fr; Catena, Vittorio, E-mail: vittoriocatena@gmail.com [Institut Bergonié, Department of Radiology (France); Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it; Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Università Campus Bio-Medico di Roma, Department of Radiology and Diagnostic Imaging (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Università Campus Bio-Medico di Roma, Unit of Measurements and Biomedical Instrumentations, Biomedical Engineering Laboratory (Italy); Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr; Palussiere, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France)

    2015-10-15

    AimTo compare cone-beam CT (CBCT) versus computed tomography (CT) guidance in terms of time needed to target and place the radiofrequency ablation (RFA) electrode on lung tumours.Materials and MethodsPatients at our institution who received CBCT- or CT-guided RFA for primary or metastatic lung tumours were retrospectively included. Time required to target and place the RFA electrode within the lesion was registered and compared across the two groups. Lesions were stratified into three groups according to their size (<10, 10–20, >20 mm). Occurrences of electrode repositioning, repositioning time, RFA complications, and local recurrence after RFA were also reported.ResultsForty tumours (22 under CT, 18 under CBCT guidance) were treated in 27 patients (19 male, 8 female, median age 67.25 ± 9.13 years). Thirty RFA sessions (16 under CBCT and 14 under CT guidance) were performed. Multivariable linear regression analysis showed that CBCT was faster than CT to target and place the electrode within the tumour independently from its size (β = −9.45, t = −3.09, p = 0.004). Electrode repositioning was required in 10/22 (45.4 %) tumours under CT guidance and 5/18 (27.8 %) tumours under CBCT guidance. Pneumothoraces occurred in 6/14 (42.8 %) sessions under CT guidance and in 6/16 (37.5 %) sessions under CBCT guidance. Two recurrences were noted for tumours receiving CBCT-guided RFA (2/17, 11.7 %) and three after CT-guided RFA (3/19, 15.8 %).ConclusionCBCT with live 3D needle guidance is a useful technique for percutaneous lung ablation. Despite lesion size, CBCT allows faster lung RFA than CT.

  1. Deformable registration of CT and cone-beam CT by local CBCT intensity correction

    Science.gov (United States)

    Park, Seyoun; Plishker, William; Shekhar, Raj; Quon, Harry; Wong, John; Lee, Junghoon

    2015-03-01

    In this paper, we propose a method to accurately register CT to cone-beam CT (CBCT) by iteratively correcting local CBCT intensity. 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. To address this issue, we correct CBCT intensities by matching local intensity histograms slice by slice in conjunction with intensity-based deformable registration. This correction-registration step is repeated until the result image converges. We tested the proposed method on eight head-and-neck cancer cases and compared its performance with state-of-the-art registration methods, Bspline, demons, and optical flow, which are widely used for CT-CBCT registration. Normalized mutual-information (NMI), normalized cross-correlation (NCC), and structural similarity (SSIM) were computed as similarity measures for the performance evaluation. Our method produced overall NMI of 0.59, NCC of 0.96, and SSIM of 0.93, outperforming existing methods by 3.6%, 2.4%, and 2.8% in terms of NMI, NCC, and SSIM scores, respectively. Experimental results show that our method is more consistent and roust than existing algorithms, and also computationally efficient with faster convergence.

  2. Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Estrela, Carlos; Porto, Olavo Cesar Lyra; Rodrigues, Cleomar Donizeth [Federal University of Goias (UFG), Goiania, GO (Brazil). Dental School; Bueno, Mike Reis [University of Cuiaba (UNIC), MT (Brazil). Dental School; Pecora, Jesus Djalma, E-mail: estrela3@terra.com.b [University of Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Dental School

    2009-07-01

    The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at p<0.01. The kappa value was used to assess examiner variability. From a total of 591 intracanal posts, AP was observed in 15.06%, 18.78% and 7.95% using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20%, 26.40% and 11.84% observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92%) by periapical radiography and in 614 (60.19%) by CBCT scans (p<0.001). The distribution of intracanal posts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79%). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used. (author)

  3. Agreement between cone-beam computed tomography and nasoendoscopy evaluations of adenoid hypertrophy.

    Science.gov (United States)

    Major, Michael P; Witmans, Manisha; El-Hakim, Hamdy; Major, Paul W; Flores-Mir, Carlos

    2014-10-01

    The goals of this study were to evaluate (1) the reliability and accuracy of cone-beam computed tomography (CBCT) for assessing adenoid size compared with nasoendoscopy and (2) the influence of clinical experience on CBCT diagnosis. Adenoid size was graded on a 4-point scale for CBCT and nasoendoscopy by a pediatric otolaryngologist. Reliability was assessed with intraobserver and interobserver agreement. Accuracy was assessed with agreement between CBCT and nasoendoscopy, plus sensitivity and specificity analyses. The CBCT assessments were completed by a team of 4 evaluators: an oral and maxillofacial radiologist, an airway orthodontist who participates in the multidisciplinary team, an academic orthodontist whose primary research is in 3-dimensional imaging, and a highly experienced private practice orthodontist comfortable with CBCT imaging. Each evaluator was specifically chosen to represent a unique set of clinical and radiographic experiences. All evaluators were blinded to the subject's identity and clinical history, and they evaluated the images in a unique random order and evaluated each image 3 times separated by a minimum of 7 days. The same computer hardware and software were used. Thirty-nine consecutively assessed, nonsyndromic subjects (ages, 11.5 ± 2.8 years) were evaluated. The CBCT demonstrated excellent sensitivity (88%) and specificity (93%), strong accuracy (ICC, 0.80; 95% CI, ± 0.15), and good reliability, both within observers (ICC, 0.85; 95% CI, ± 0.08) and between observers (ICC, 0.84; 95% CI, ± 0.08). The clinical experience of the CBCT evaluator did not have a statistically significant effect. CBCT is a reliable and accurate tool for identifying adenoid hypertrophy. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  4. Fully automatic segmentation of arbitrarily shaped fiducial markers in cone-beam CT projections

    Science.gov (United States)

    Bertholet, J.; Wan, H.; Toftegaard, J.; Schmidt, M. L.; Chotard, F.; Parikh, P. J.; Poulsen, P. R.

    2017-02-01

    Radio-opaque fiducial markers of different shapes are often implanted in or near abdominal or thoracic tumors to act as surrogates for the tumor position during radiotherapy. They can be used for real-time treatment adaptation, but this requires a robust, automatic segmentation method able to handle arbitrarily shaped markers in a rotational imaging geometry such as cone-beam computed tomography (CBCT) projection images and intra-treatment images. In this study, we propose a fully automatic dynamic programming (DP) assisted template-based (TB) segmentation method. Based on an initial DP segmentation, the DPTB algorithm generates and uses a 3D marker model to create 2D templates at any projection angle. The 2D templates are used to segment the marker position as the position with highest normalized cross-correlation in a search area centered at the DP segmented position. The accuracy of the DP algorithm and the new DPTB algorithm was quantified as the 2D segmentation error (pixels) compared to a manual ground truth segmentation for 97 markers in the projection images of CBCT scans of 40 patients. Also the fraction of wrong segmentations, defined as 2D errors larger than 5 pixels, was calculated. The mean 2D segmentation error of DP was reduced from 4.1 pixels to 3.0 pixels by DPTB, while the fraction of wrong segmentations was reduced from 17.4% to 6.8%. DPTB allowed rejection of uncertain segmentations as deemed by a low normalized cross-correlation coefficient and contrast-to-noise ratio. For a rejection rate of 9.97%, the sensitivity in detecting wrong segmentations was 67% and the specificity was 94%. The accepted segmentations had a mean segmentation error of 1.8 pixels and 2.5% wrong segmentations.

  5. Determination of size-specific exposure settings in dental cone-beam CT.

    Science.gov (United States)

    Pauwels, Ruben; Jacobs, Reinhilde; Bogaerts, Ria; Bosmans, Hilde; Panmekiate, Soontra

    2017-01-01

    To estimate the possible reduction of tube output as a function of head size in dental cone-beam computed tomography (CBCT). A 16 cm PMMA phantom, containing a central and six peripheral columns filled with PMMA, was used to represent an average adult male head. The phantom was scanned using CBCT, with 0-6 peripheral columns having been removed in order to simulate varying head sizes. For five kV settings (70-90 kV), the mAs required to reach a predetermined image noise level was determined, and corresponding radiation doses were derived. Results were expressed as a function of head size, age, and gender, based on growth reference charts. The use of 90 kV consistently resulted in the largest relative dose reduction. A potential mAs reduction ranging from 7 % to 50 % was seen for the different simulated head sizes, showing an exponential relation between head size and mAs. An optimized exposure protocol based on head circumference or age/gender is proposed. A considerable dose reduction, through reduction of the mAs rather than the kV, is possible for small-sized patients in CBCT, including children and females. Size-specific exposure protocols should be clinically implemented. • Fixed exposure settings in CBCT results in overexposure for smaller patients • For children, considerable dose reduction is possible without compromising image quality • A reduction in mAs is more dose-efficient than a kV reduction • An optimized exposure protocol was proposed based on phantom measurements • This protocol should be validated in a clinical setting.

  6. Vertical bone measurements from cone beam computed tomography images using different software packages

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Taruska Ventorini; Neves, Frederico Sampaio; Moraes, Livia Almeida Bueno; Freitas, Deborah Queiroz, E-mail: tataventorini@hotmail.com [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Faculdade de Odontologia

    2015-03-01

    This article aimed at comparing the accuracy of linear measurement tools of different commercial software packages. Eight fully edentulous dry mandibles were selected for this study. Incisor, canine, premolar, first molar and second molar regions were selected. Cone beam computed tomography (CBCT) images were obtained with i-CAT Next Generation. Linear bone measurements were performed by one observer on the cross-sectional images using three different software packages: XoranCat®, OnDemand3D® and KDIS3D®, all able to assess DICOM images. In addition, 25% of the sample was reevaluated for the purpose of reproducibility. The mandibles were sectioned to obtain the gold standard for each region. Intraclass coefficients (ICC) were calculated to examine the agreement between the two periods of evaluation; the one-way analysis of variance performed with the post-hoc Dunnett test was used to compare each of the software-derived measurements with the gold standard. The ICC values were excellent for all software packages. The least difference between the software-derived measurements and the gold standard was obtained with the OnDemand3D and KDIS3D (‑0.11 and ‑0.14 mm, respectively), and the greatest, with the XoranCAT (+0.25 mm). However, there was no statistical significant difference between the measurements obtained with the different software packages and the gold standard (p > 0.05). In conclusion, linear bone measurements were not influenced by the software package used to reconstruct the image from CBCT DICOM data. (author)

  7. Prevalence and location of the posterior superior alveolar artery using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tehranchi, Maryam; Taleghani, Ferial; Shahab, Shahriar [Faculty of Dentistry, Shahed University, Tehran (Iran, Islamic Republic of); Nouri, Arash [Nouri' s Dental Clinic, Tehran (Iran, Islamic Republic of)

    2017-03-15

    Insufficient knowledge of the anatomy of the maxillary sinuses prior to sinus graft surgery may lead to perioperative or postoperative complications. This study sought to characterize the position of the posterior superior alveolar artery (PSAA) within the maxillary sinuses using cone-beam computed tomography (CBCT). A total of 300 patients with edentulous posterior maxillae, including 138 females and 162 males with an age range of 33-86 years, who presented to a radiology clinic between 2013 and 2015 were enrolled in this retrospective cross-sectional study. The distance from the inferior border of the PSAA to the alveolar crest according to the residual ridge classification by Lekholm and Zarb, the distance from the PSAA to the nasal septum and zygomatic arch, and the diameter and position of the PSAA were all assessed on patients' CBCT scans. The data were analyzed using the Mann-Whitney test and the t-test. The PSAA was detected on the CBCT scans of 87% of the patients; it was located beneath the sinus membrane in 47% of cases and was intraosseous in 47% of cases. The diameter of the artery was between 1 and 2 mm in most patients (72%). The mean diameter of the artery was 1.29±0.39 mm, and the mean distances from the PSAA to the zygomatic arch, nasal septum, and alveolar crest were 22.59±4.89 mm, 26.51±3.52 mm, and 16.7±3.96 mm, respectively. The likelihood of detecting the PSAA on CBCT scans is high; its location is intraosseous or beneath the sinus membrane in most patients. Determining the exact location of the PSAA on CBCT scans preoperatively can help prevent it from being damaged during surgery.

  8. Comparison between cone beam computed tomography and magnetic resonance imaging of the temporomandibular joint

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry and Institute of Oral Biology, Kyung Hee University, Seoul (Korea, Republic of)

    2008-09-15

    To compare and evaluate the diagnostic ability of cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). CBCT and MRI of 46 TMJs of 23 patients with TMJ disorders were evaluated. They were divided into 3 groups according to the position of the articular disc of the TMJ at closed mouth position and the reduction of the disc during open mouth position on MRI: no disc displacement group (NDD), disc displacement with reduction group (DDR), and disc displacement without reduction group (DDWR). With PACS viewing software, position of mandibular condyle in the articular fossa, osseous change of mandibular condyle, shape of articular fossa, and mediolateral and anteroposterior dimensions of mandibular condyle were evaluated on CBCT and MRI. Each value was tested statistically. The position of mandibular condyle in the articular fossa were concentric in the NDD, DDR, and DDWR of CBCT and NDD of MRI. However, condyle was positioned posteriorly in DDR and DDWR of MRI. Flattening, sclerosis and osteophyte of the mandibular condyle were much more apparent on DDR of CBCT than MRI. And the erosion of the condyle was much more apparent on DDWR of MRI than CBCT. Box and Sigmoid types of articular fossa were found most frequently in DDR of MRI. Flattened type was found most frequently in DDR of CBCT and deformed type was found most frequently in DDWR of CBCT. No significant difference in mediolateral and anteroposterior dimensions were shown on CBCT and MRI. Since MRI and CBCT has unique diagnostic imaging ability, both modalities should be used together to supplement each other to evaluate TMJ.

  9. Intravenous contrast media application using cone-beam computed tomography in a rabbit model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Sung; Kim, Bok Yeol; Choi, Hwa Young [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of); and others

    2015-03-15

    This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.

  10. Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Kazunori, E-mail: kazokada@sfsu.edu [Department of Computer Science, San Francisco State University, San Francisco, California 94132 (United States); Rysavy, Steven [Biomedical and Health Informatics Program, University of Washington, Seattle, Washington 98195 (United States); Flores, Arturo [Computer Science and Engineering, University of California, San Diego, California 92093 (United States); Linguraru, Marius George [Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Medical Center, Washington, DC 20010 and Departments of Radiology and Pediatrics, George Washington University, Washington, DC 20037 (United States)

    2015-04-15

    Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.

  11. Malocclusion Class II division 1 skeletal and dental relationships measured by cone-beam computed tomography.

    Science.gov (United States)

    Xu, Yiling; Oh, Heesoo; Lagravère, Manuel O

    2017-09-01

    The purpose of this study was to locate traditionally-used landmarks in two-dimensional (2D) images and newly-suggested ones in three-dimensional (3D) images (cone-beam computer tomographies [CBCTs]) and determine possible relationships between them to categorize patients with Class II-1 malocclusion. CBCTs from 30 patients diagnosed with Class II-1 malocclusion were obtained from the University of Alberta Graduate Orthodontic Program database. The reconstructed images were downloaded and visualized using the software platform AVIZO(®). Forty-two landmarks were chosen and the coordinates were then obtained and analyzed using linear and angular measurements. Ten images were analyzed three times to determine the reliability and measurement error of each landmark using Intra-Class Correlation coefficient (ICC). Descriptive statistics were done using the SPSS statistical package to determine any relationships. ICC values were excellent for all landmarks in all axes, with the highest measurement error of 2mm in the y-axis for the Gonion Left landmark. Linear and angular measurements were calculated using the coordinates of each landmark. Descriptive statistics showed that the linear and angular measurements used in the 2D images did not correlate well with the 3D images. The lowest standard deviation obtained was 0.6709 for S-GoR/N-Me, with a mean of 0.8016. The highest standard deviation was 20.20704 for ANS-InfraL, with a mean of 41.006. The traditional landmarks used for 2D malocclusion analysis show good reliability when transferred to 3D images. However, they did not reveal specific skeletal or dental patterns when trying to analyze 3D images for malocclusion. Thus, another technique should be considered when classifying 3D CBCT images for Class II-1malocclusion. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

  12. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT)

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Corpas, Livia, E-mail: LiviaCorpas@gmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Souza, Paulo Couto, E-mail: Paulo.CoutoSouza@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Martens, Wendy, E-mail: wendy.martens@uhasselt.b [Department of Basic Medical Sciences, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Shahbazian, Maryam, E-mail: Maryam.Shahbazian@student.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Alonso, Arie, E-mail: ariel.alonso@uhasselt.b [Department of Biostatistics and Statistical Bioinformatics, Universiteit Hasselt (Belgium)

    2010-08-15

    Aims: To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale. Results: Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p = 0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p = 0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise. Conclusions: CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.

  13. Design and optimization of a dedicated cone-beam CT system for musculoskeletal extremities imaging

    Science.gov (United States)

    Zbijewski, W.; De Jean, P.; Prakash, P.; Ding, Y.; Stayman, J. W.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Machado, A.; Carrino, J. A.; Siewerdsen, J. H.

    2011-03-01

    The design, initial imaging performance, and model-based optimization of a dedicated cone-beam CT (CBCT) scanner for musculoskeletal extremities is presented. The system offers a compact scanner that complements conventional CT and MR by providing sub-mm isotropic spatial resolution, the ability to image weight-bearing extremities, and the capability for integrated real-time fluoroscopy and digital radiography. The scanner employs a flat-panel detector and a fixed anode x-ray source and has a field of view of ~ (20x20x20) cm3. The gantry allows a "standing" configuration for imaging of weight-bearing lower extremities and a "sitting" configuration for imaging of upper extremities and unloaded lower extremities. Cascaded systems analysis guided the selection of x-ray technique (e.g., kVp, filtration, and dose) and system design (e.g., magnification factor), yielding input-quantum-limited performance at detector signal of 100 times the electronic noise, while maintaining patient dose below 5 mGy (a factor of ~2-3 less than conventional CT). A magnification of 1.3 optimized tradeoffs between source and detector blur for a 0.5 mm focal spot. A custom antiscatter grid demonstrated significant reduction of artifacts without loss of contrast-to-noise ratio or increase in dose. Image quality in cadaveric specimens was assessed on a CBCT bench, demonstrating exquisite bone detail, visualization of intra-articular morphology, and soft-tissue visibility approaching that of diagnostic CT. The capability to image loaded extremities and conduct multi-modality CBCT/fluoroscopy with improved workflow compared to whole-body CT could be of value in a broad spectrum of applications, including orthopaedics, rheumatology, surgical planning, and treatment assessment. A clinical prototype has been constructed for deployment in pilot study trials.

  14. Clinical Application of Cone-Beam Computed Tomography of the Rabbit Head: Part 1 - Normal Dentition

    Directory of Open Access Journals (Sweden)

    GG Comet Riggs

    2016-10-01

    Full Text Available Domestic rabbits (Oryctolagus cuniculus are increasingly popular as household pets; therefore, veterinarians need to be familiar with the most common diseases afflicting rabbits including dental diseases. Diagnostic approaches for dental disease include gross oral examination, endoscopic oral examination, skull radiography, and computed tomography (CT. CT overcomes many limitations of standard radiography by permitting cross-sectional images of the rabbit head in multiple planes without superimposition of anatomic structures. Cone-beam CT (CBCT is an oral and maxillofacial imaging modality that produces high-resolution images. The objective of this study was to describe and compare the normal anatomic features of the dentition and surrounding maxillofacial structures in healthy rabbits on CBCT and conventional CT. Ten New Zealand white rabbit cadaver heads were scanned using CBCT and conventional CT. Images were evaluated using Anatomage Invivo 5 software. The maxillofacial anatomy was labeled on CBCT images and the mean lengths and widths of the teeth were determined. The visibility of relevant dental and anatomic features (pulp cavity, germinal center, tooth outline, periodontal ligament were scored and compared between conventional CT and CBCT. The thinnest teeth were the maxillary second incisor teeth at 1.29 ± 0.26 mm and the maxillary third molar teeth at 1.04 ±0.10 mm. In general, it was found that CBCT was superior to conventional CT when imaging the dentition. Importantly, the periodontal ligament was significantly (P<0.01 more visible on CBCT than on conventional CT. Ability to see the periodontal ligament with such detail may allow earlier detection and treatment of periodontal disease in rabbits. This study is the first of its kind and shows the feasibility and yield of CBCT when evaluating the maxillofacial features and dentition in rabbits.

  15. A cone-beam computed tomography evaluation of buccal bone thickness following maxillary expansion

    Energy Technology Data Exchange (ETDEWEB)

    Akyalcin, Sercan; Englih, Jeryl D.; Stephens, Claude R.; Winkelmann, Sam [Dept. of Orthodontics, School of Dentistry, University of Texas Health Science Center at Houston, Houston (United States); Schaefer, Jeffrey S. [Todd Hughes Orthodontics, Houston (United States)

    2013-06-15

    This study was performed to determine the buccal alveolar bone thickness following rapid maxillary expansion (RME) using cone-beam computed tomography (CBCT). Twenty-four individuals (15 females, 9 males; 13.9 years) that underwent RME therapy were included. Each patient had CBCT images available before (T1), after (T2), and 2 to 3 years after (T3) maxillary expansion therapy. Coronal multiplanar reconstruction images were used to measure the linear transverse dimensions, inclinations of teeth, and thickness of the buccal alveolar bone. One-way ANOVA analysis was used to compare the changes between the three times of imaging. Pairwise comparisons were made with the Bonferroni method. The level of significance was established at p<0.05. The mean changes between the points in time yielded significant differences for both molar and premolar transverse measurements between T1 and T2 (p<0.05) and between T1 and T3 (p<0.05). When evaluating the effect of maxillary expansion on the amount of buccal alveolar bone, a decrease between T1 and T2 and an increase between T2 and T3 were found in the buccal bone thickness of both the maxillary first premolars and maxillary first molars. However, these changes were not significant. Similar changes were observed for the angular measurements. RME resulted in non-significant reduction of buccal bone between T1 and T2. These changes were reversible in the long-term with no evident deleterious effects on the alveolar buccal bone.

  16. Radiation dose of cone-beam computed tomography compared to conventional radiographs in orthodontics.

    Science.gov (United States)

    Signorelli, Luca; Patcas, Raphael; Peltomäki, Timo; Schätzle, Marc

    2016-01-01

    The aim of this study was to determine radiation doses of different cone-beam computed tomography (CBCT) scan modes in comparison to a conventional set of orthodontic radiographs (COR) by means of phantom dosimetry. Thermoluminescent dosimeter (TLD) chips (3 × 1 × 1 mm) were used on an adult male tissue-equivalent phantom to record the distribution of the absorbed radiation dose. Three different scanning modes (i.e., portrait, normal landscape, and fast scan landscape) were compared to CORs [i.e., conventional lateral (LC) and posteroanterior (PA) cephalograms and digital panoramic radiograph (OPG)]. The following radiation levels were measured: 131.7, 91, and 77 μSv in the portrait, normal landscape, and fast landscape modes, respectively. The overall effective dose for a COR was 35.81 μSv (PA: 8.90 μSv; OPG: 21.87 μSv; LC: 5.03 μSv). Although one CBCT scan may replace all CORs, one set of CORs still entails 2-4 times less radiation than one CBCT. Depending on the scan mode, the radiation dose of a CBCT is about 3-6 times an OPG, 8-14 times a PA, and 15-26 times a lateral LC. Finally, in order to fully reconstruct cephalograms including the cranial base and other important structures, the CBCT portrait mode must be chosen, rendering the difference in radiation exposure even clearer (131.7 vs. 35.81 μSv). Shielding radiation-sensitive organs can reduce the effective dose considerably. CBCT should not be recommended for use in all orthodontic patients as a substitute for a conventional set of radiographs. In CBCT, reducing the height of the field of view and shielding the thyroid are advisable methods and must be implemented to lower the exposure dose.

  17. Evidence supporting the use of cone-beam computed tomography in orthodontics.

    Science.gov (United States)

    van Vlijmen, Olivier J C; Kuijpers, Mette A R; Bergé, Stefaan J; Schols, Jan G J H; Maal, Thomas J J; Breuning, Hero; Kuijpers-Jagtman, Anne Marie

    2012-03-01

    The authors conducted a systematic review of cone-beam computed tomography (CBCT) applications in orthodontics and evaluated the level of evidence to determine whether the use of CBCT is justified in orthodontics. The authors identified articles by searching the Cochrane Library, PubMed, MEDLINE, Embase, Scopus and Cumulative Index to Nursing and Allied Health Literature databases. They searched the articles' reference lists manually for additional articles and had no language limitations. They did not search the gray literature. Inclusion criteria were CBCT use in orthodontics and that the participants be human. The lowest level of evidence accepted for inclusion was a case series with five or more participants. The authors evaluated the studies' methodological quality according to 13 criteria related to study design, measurements and statistical analysis. The authors identified 550 articles, and 50 met the inclusion criteria. Study topics included temporary anchorage devices, cephalometry, combined orthodontic and surgical treatment, airway measurements, root resorption and tooth impactions, and cleft lip and palate. The methodological quality averaged 53 percent (range, 15-77 percent) of the maximum score. The authors found no high-quality evidence regarding the benefits of CBCT use in orthodontics. Limited evidence shows that CBCT offers better diagnostic potential, leads to better treatment planning or results in better treatment outcome than do conventional imaging modalities. Only the results of studies on airway diagnostics provided sound scientific data suggesting that CBCT use has added value. The additional radiation exposure should be weighed against possible benefits of CBCT, which have not been supported in the literature. In future studies, investigators should evaluate the effects of CBCT on treatment procedures, progression and outcome quantitatively.

  18. Prevalence and location of the posterior superior alveolar artery using cone-beam computed tomography

    Science.gov (United States)

    Tehranchi, Maryam; Shahab, Shahriar; Nouri, Arash

    2017-01-01

    Purpose Insufficient knowledge of the anatomy of the maxillary sinuses prior to sinus graft surgery may lead to perioperative or postoperative complications. This study sought to characterize the position of the posterior superior alveolar artery (PSAA) within the maxillary sinuses using cone-beam computed tomography (CBCT). Materials and Methods A total of 300 patients with edentulous posterior maxillae, including 138 females and 162 males with an age range of 33-86 years, who presented to a radiology clinic between 2013 and 2015 were enrolled in this retrospective cross-sectional study. The distance from the inferior border of the PSAA to the alveolar crest according to the residual ridge classification by Lekholm and Zarb, the distance from the PSAA to the nasal septum and zygomatic arch, and the diameter and position of the PSAA were all assessed on patients' CBCT scans. The data were analyzed using the Mann-Whitney test and the t-test. Results The PSAA was detected on the CBCT scans of 87% of the patients; it was located beneath the sinus membrane in 47% of cases and was intraosseous in 47% of cases. The diameter of the artery was between 1 and 2 mm in most patients (72%). The mean diameter of the artery was 1.29±0.39 mm, and the mean distances from the PSAA to the zygomatic arch, nasal septum, and alveolar crest were 22.59±4.89 mm, 26.51±3.52 mm, and 16.7±3.96 mm, respectively. Conclusion The likelihood of detecting the PSAA on CBCT scans is high; its location is intraosseous or beneath the sinus membrane in most patients. Determining the exact location of the PSAA on CBCT scans preoperatively can help prevent it from being damaged during surgery. PMID:28361028

  19. A suggested technique for the application of the cone beam computed tomography periapical index.

    Science.gov (United States)

    Esposito, S; Cardaropoli, M; Cotti, E

    2011-12-01

    Cone beam CT (CBCT) produces undistorted three-dimensional (3D) images of the maxillofacial region with a radiation dosage lower than conventional CT. The periapical index score (PAI) is commonly used to follow up the lesions in the bone using periapical radiographs. Recently, a new PAI based on CBCT was introduced (CBCT-PAI). The aim of this technical report is to present a modified reproducible method to assess the CBCT-PAI. CBCT was used to evaluate a periapical bone lesion observed in the area of tooth number 13 before treatment and 2 years after treatment. The modified CBCT-PAI was applied to both the examinations to measure the lesion. The dimensional analysis of the lesion was performed in each plane, assessing three fixed and reproducible dimensions: mesiodistal (M-D), buccolingual (B-L) and coronoapical (C-A). The images were evaluated by three mutually independent examiners. Data were collected and reported in a chart. The results were compared with each other and with the PAI score from the periapical radiographs. The three observers reported the same measurements of the lesion for each plane. The CBCT-PAI follow-up showed a reduction of the size of the lesion (5D vs 4D) but also an increase in the erosion of the buccal cortical plate. The comparison of CBCT-PAI with classic PAI showed the first method to be more precise. This technical report shows how the CBCT-PAI can be applied to the CBCT exam of a periapical lesion in a reproducible way.

  20. Three-dimensional cone-beam computed tomography for assessment of mandibular changes after orthognathic surgery

    Science.gov (United States)

    Cevidanes, Lucia H. S.; Bailey, L'Tanya J.; Tucker, Scott F.; Styner, Martin A.; Mol, Andre; Phillips, Ceib L.; Proffit, William R.; Turvey, Timothy

    2013-01-01

    Introduction The purpose of this study was to assess alterations in the 3-dimensional (3D) position of the mandibular rami and condyles in patients receiving either maxillary advancement and mandibular setback or maxillary surgery only. Methods High-resolution cone-beam computed tomography scans were taken of 21 patients before and after orthognathic surgery. Ten patients with various malocclusions underwent maxillary surgery only, and 11 Class III patients received maxillary advancement and mandibular setback. Presurgery and postsurgery 3D models were registered on the surface of the cranial base. A new tool was used for graphical overlay and 3D display with color maps to visually assess the locations and to quantify positional changes in the posterior border of the mandibular rami and condyles between superimposed models. Results The average displacements in condylar position were small—0.77 mm (SD, 0.12 mm) and 0.70 mm (SD, 0.08 mm)—for 2-jaw and 1-jaw surgeries, respectively (not significant, P >.05). All 2-jaw surgery patients had backward rotational displacements of the mandibular rami (mean, 1.98 mm; SD, 1.03 mm), with a maximum surface distance change of ≥2 mm in 8 of 11 subjects. For the 1-jaw surgery, all subjects had small backward rotational displacements of the mandibular rami (mean, 0.78 mm; SD, 0.25 mm), with only 1 subject having a maximum surface distance change ≥2 mm. The difference in mean backward rotational displacement was statistically significant (P <.01). Conclusions The visualization of 3D model superimposition clearly identified the location, magnitude, and direction of mandibular displacement. The 3D imaging allowed quantification of vertical, transverse, and anteroposterior ramus displacement that accompanied mandibular, but not maxillary only, surgery. PMID:17208105