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Sample records for beam computed tomography

  1. Noninvasive coronary angioscopy using electron beam computed tomography and multidetector computed tomography

    NARCIS (Netherlands)

    van Ooijen, PMA; Nieman, K; de Feyter, PJ; Oudkerk, M

    2002-01-01

    With the advent of noninvasive coronary imaging techniques like multidetector computed tomography and electron beam computed tomography, new representation methods such as intracoronary visualization. have been introduced. We explore the possibilities of these novel visualization techniques and comp

  2. 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)

  3. Cone beam computed tomography in endodontic

    International Nuclear Information System (INIS)

    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)

  4. Skeletal dosimetry in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Walters, B. R. B.; Ding, G. X.; Kramer, R.; Kawrakow, I. [Ionizing Radiation Standards, National Research Council of Canada, Ottawa K1A OR6 (Canada); Department of Radiation Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-5671 (United States); Departamento de Energia Nuclear, Universidade Federal de Pernambuco, Avenida Professor Luiz Freire 1000, Cidade Universitaria, CEP 50740-540, Recife, Pernambuco (Brazil); Ionizing Radiation Standards, National Research Council of Canada, Ottawa K1A OR6 (Canada)

    2009-07-15

    Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. In this study, voxelized human phantoms, FAX06 (adult female) and MAX06 (adult male), are used together with phase-space data collected from a realistic model of a CBCT imager to calculate dose in the red bone marrow (RBM) and bone surface cells (BSCs), the two organs at risk within the bone spongiosa, during simulated head and neck, chest and pelvis CBCT scans. The FAX06/MAX06 phantoms model spongiosa based on micro-CT images, filling the relevant phantom voxels, which are 0.12x0.12x0.12 cm{sup 3}, with 17x17x17 {mu}m{sup 3} microvoxels to form a micromatrix of trabecular bone and bone marrow. FAX06/MAX06 have already been implemented in an EGSnrc-based Monte Carlo code to simulate radiation transport in the phantoms; however, this study required significant modifications of the code to allow use of phase-space data from a simulated CBCT imager as a source and to allow scoring of total dose, RBM dose and BSC dose on a voxel-by-voxel basis. In simulated CBCT scans, the BSC dose is significantly greater than the dose to other organs at risk. For example, in a simulated head and neck scan, the average BSC dose is 25% higher than the average dose to eye lens ({approx}8.3 cGy), and 80% greater than the average dose to brain (5.7 cGy). Average dose to RBM, on the other hand, is typically only {approx}50% of the average BSC dose and less than the dose to other organs at risk (54% of the dose to eye lens and 76% of dose to brain in a head and neck scan). Thus, elevated dose in bone due to CBCT results in elevated BSC dose. This is potentially of concern when using CBCT in conjunction with radiotherapy treatment.

  5. Skeletal dosimetry in cone beam computed tomography.

    Science.gov (United States)

    Walters, B R B; Ding, G X; Kramer, R; Kawrakow, I

    2009-07-01

    Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. In this study, voxelized human phantoms, FAX06 (adult female) and MAX06 (adult male), are used together with phase-space data collected from a realistic model of a CBCT imager to calculate dose in the red bone marrow (RBM) and bone surface cells (BSCs), the two organs at risk within the bone spongiosa, during simulated head and neck, chest and pelvis CBCT scans. The FAX06/MAX06 phantoms model spongiosa based on micro-CT images, filling the relevant phantom voxels, which are 0.12 x 0.12 x 0.12 cm3, with 17 x 17 x 17 microm3 microvoxels to form a micromatrix of trabecular bone and bone marrow. FAX06/ MAX06 have already been implemented in an EGSnrc-based Monte Carlo code to simulate radiation transport in the phantoms; however, this study required significant modifications of the code to allow use of phase-space data from a simulated CBCT imager as a source and to allow scoring of total dose, RBM dose and BSC dose on a voxel-by-voxel basis. In simulated CBCT scans, the BSC dose is significantly greater than the dose to other organs at risk. For example, in a simulated head and neck scan, the average BSC dose is 25% higher than the average dose to eye lens (approximately 8.3 cGy), and 80% greater than the average dose to brain (5.7 cGy). Average dose to RBM, on the other hand, is typically only approximately 50% of the average BSC dose and less than the dose to other organs at risk (54% of the dose to eye lens and 76% of dose to brain in a head and neck scan). Thus, elevated dose in bone due to CBCT results in elevated BSC dose. This is potentially of concern when using CBCT in conjunction with radiotherapy treatment. PMID:19673190

  6. Skeletal dosimetry in cone beam computed tomography

    International Nuclear Information System (INIS)

    Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. In this study, voxelized human phantoms, FAX06 (adult female) and MAX06 (adult male), are used together with phase-space data collected from a realistic model of a CBCT imager to calculate dose in the red bone marrow (RBM) and bone surface cells (BSCs), the two organs at risk within the bone spongiosa, during simulated head and neck, chest and pelvis CBCT scans. The FAX06/MAX06 phantoms model spongiosa based on micro-CT images, filling the relevant phantom voxels, which are 0.12x0.12x0.12 cm3, with 17x17x17 μm3 microvoxels to form a micromatrix of trabecular bone and bone marrow. FAX06/MAX06 have already been implemented in an EGSnrc-based Monte Carlo code to simulate radiation transport in the phantoms; however, this study required significant modifications of the code to allow use of phase-space data from a simulated CBCT imager as a source and to allow scoring of total dose, RBM dose and BSC dose on a voxel-by-voxel basis. In simulated CBCT scans, the BSC dose is significantly greater than the dose to other organs at risk. For example, in a simulated head and neck scan, the average BSC dose is 25% higher than the average dose to eye lens (∼8.3 cGy), and 80% greater than the average dose to brain (5.7 cGy). Average dose to RBM, on the other hand, is typically only ∼50% of the average BSC dose and less than the dose to other organs at risk (54% of the dose to eye lens and 76% of dose to brain in a head and neck scan). Thus, elevated dose in bone due to CBCT results in elevated BSC dose. This is potentially of concern when using CBCT in conjunction with radiotherapy treatment.

  7. 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.

  8. Use of dentomaxillofacial cone beam computed tomography in dentistry

    OpenAIRE

    KAMBUROĞLU, Kıvanç

    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 ina...

  9. Use of Cone Beam Computed Tomography in Endodontics

    OpenAIRE

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

    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...

  10. Use of Cone Beam Computed Tomography in Endodontics

    Directory of Open Access Journals (Sweden)

    William C. Scarfe

    2009-01-01

    Full Text Available 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.

  11. High Resolution Muon Computed Tomography at Neutrino Beam Facilities

    CERN Document Server

    Suerfu, Burkhant

    2015-01-01

    X-ray computed tomography (CT) has an indispensable role in constructing 3D images of objects made from light materials. However, limited by absorption coefficients, X-rays cannot deeply penetrate materials such as copper and lead. Here we show via simulation that muon beams can provide high resolution tomographic images of dense objects and of structures within the interior of dense objects. The effects of resolution broadening from multiple scattering diminish with increasing muon momentum. As the momentum of the muon increases, the contrast of the image goes down and therefore requires higher resolution in the muon spectrometer to resolve the image. The variance of the measured muon momentum reaches a minimum and then increases with increasing muon momentum. The impact of the increase in variance is to require a higher integrated muon flux to reduce fluctuations. The flux requirements and level of contrast needed for high resolution muon computed tomography are well matched to the muons produced in the pio...

  12. Beam standardization and dosimetric methodology in computed tomography

    International Nuclear Information System (INIS)

    Special ionization chambers, named pencil ionization chambers, are used in dosimetric procedures in computed tomography beams (CT). In this work, an extensive study about pencil ionization chambers was performed, as a contribution to the accuracy of the dosimetric procedures in CT beams. The international scientific community has recently been discussing the need of the establishment of a specific calibration procedure for CT ionization chambers, once these chambers present special characteristics that differentiate them from other ionization chambers used in diagnostic radiology beams. In this work, an adequate calibration procedure for pencil ionization chambers was established at the Calibration Laboratory, of the Institute de Pesquisas Energeticas e Nucleares, in accordance with the most recent international recommendations. Two calibration methodologies were tested and analyzed by comparative studies. Moreover, a new extended length parallel plate ionization chamber, with a transversal section very similar to pencil ionization chambers, was developed. The operational characteristics of this chamber were determined and the results obtained showed that its behaviour is adequate as a reference system in CT standard beams. Two other studies were performed during this work, both using CT ionization chambers. The first study was about the performance of a pencil ionization chamber in standard radiation beams of several types and energies, and the results showed that this chamber presents satisfactory behaviour in other radiation qualities as of diagnostic radiology, mammography and radiotherapy. In the second study, a tandem system for verification of hal'-value layer variations in CT equipment, using a pencil ionization chamber, was developed. Because of the X rays tube rotation, the determination of half-value layers in computed tomography equipment is not an easy task, and it is usually not performed within quality control programs. (author)

  13. 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

  14. Finger fractures imaging: accuracy of cone-beam computed tomography and multislice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, Niccolo; Foti, Giovanni; Barillari, Marco; Mucelli, Roberto Pozzi [University of Verona, Department of Radiology, G.B. Rossi Hospital, Verona (Italy); Atzei, Andrea [University of Verona, Department of Hand Surgery, G.B. Rossi Hospital, Verona (Italy)

    2010-11-15

    To compare the diagnostic accuracy and radiation exposure of cone beam computed tomography (CBCT) and multislice computed tomography (MSCT) in the evaluation of finger fractures. In a 3-year period, 57 consecutive patients with post-traumatic fractures of the metacarpal-phalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints with involvement of the articular surface were studied by means of CBCT and MSCT. Student's t test was used to compare CBCT and MSCT accuracy in evaluating the percentage of joint surface involvement and in detecting bone fragments. The average tissue-absorbed doses of CBCT and MSCT were also compared. A value of p < 0.05 was considered statistically significant. Inter-observer agreement was calculated. In all cases, CBCT allowed the percentage of articular involvement to be correctly depicted compared with MSCT, showing 100% sensitivity and specificity (p < 0.001). A total of 103 bone fragments were depicted on MSCT (mean 3.8 per patient, range 1-23). CBCT indicated 92 out of 103 fragments (89.3%) compared with MSCT (mean diameter of missed fragments 0.9 mm, range 0.6-1.3 mm), with no statistically significant difference between CBCT and MSCT (p < 0.025). Multislice CT radiation exposure was significantly higher than that of CBCT (0.18 mSv vs 0.06 mSv, p < 0.0025). Inter-observer agreement was good (overall {kappa} = 0.89-0.96). Cone beam CT may be considered a valuable imaging tool in the preoperative assessment of finger fractures, when MSCT is not available. (orig.)

  15. High resolution muon computed tomography at neutrino beam facilities

    International Nuclear Information System (INIS)

    X-ray computed tomography (CT) has an indispensable role in constructing 3D images of objects made from light materials. However, limited by absorption coefficients, X-rays cannot deeply penetrate materials such as copper and lead. Here we show via simulation that muon beams can provide high resolution tomographic images of dense objects and of structures within the interior of dense objects. The effects of resolution broadening from multiple scattering diminish with increasing muon momentum. As the momentum of the muon increases, the contrast of the image goes down and therefore requires higher resolution in the muon spectrometer to resolve the image. The variance of the measured muon momentum reaches a minimum and then increases with increasing muon momentum. The impact of the increase in variance is to require a higher integrated muon flux to reduce fluctuations. The flux requirements and level of contrast needed for high resolution muon computed tomography are well matched to the muons produced in the pion decay pipe at a neutrino beam facility and what can be achieved for momentum resolution in a muon spectrometer. Such an imaging system can be applied in archaeology, art history, engineering, material identification and whenever there is a need to image inside a transportable object constructed of dense materials

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

    Science.gov (United States)

    Mupparapu, Mel

    2016-01-01

    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. PMID:27051639

  17. 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.

  18. A pencil beam approach to proton computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rescigno, Regina, E-mail: regina.rescigno@iphc.cnrs.fr; Bopp, Cécile; Rousseau, Marc; Brasse, David [Université de Strasbourg, IPHC, 23 rue du Loess, Strasbourg 67037, France and CNRS, UMR7178, Strasbourg 67037 (France)

    2015-11-15

    Purpose: A new approach to proton computed tomography (pCT) is presented. In this approach, protons are not tracked one-by-one but a beam of particles is considered instead. The elements of the pCT reconstruction problem (residual energy and path) are redefined on the basis of this new approach. An analytical image reconstruction algorithm applicable to this scenario is also proposed. Methods: The pencil beam (PB) and its propagation in matter were modeled by making use of the generalization of the Fermi–Eyges theory to account for multiple Coulomb scattering (MCS). This model was integrated into the pCT reconstruction problem, allowing the definition of the mean beam path concept similar to the most likely path (MLP) used in the single-particle approach. A numerical validation of the model was performed. The algorithm of filtered backprojection along MLPs was adapted to the beam-by-beam approach. The acquisition of a perfect proton scan was simulated and the data were used to reconstruct images of the relative stopping power of the phantom with the single-proton and beam-by-beam approaches. The resulting images were compared in a qualitative way. Results: The parameters of the modeled PB (mean and spread) were compared to Monte Carlo results in order to validate the model. For a water target, good agreement was found for the mean value of the distributions. As far as the spread is concerned, depth-dependent discrepancies as large as 2%–3% were found. For a heterogeneous phantom, discrepancies in the distribution spread ranged from 6% to 8%. The image reconstructed with the beam-by-beam approach showed a high level of noise compared to the one reconstructed with the classical approach. Conclusions: The PB approach to proton imaging may allow technical challenges imposed by the current proton-by-proton method to be overcome. In this framework, an analytical algorithm is proposed. Further work will involve a detailed study of the performances and limitations of

  19. A pencil beam approach to proton computed tomography

    International Nuclear Information System (INIS)

    Purpose: A new approach to proton computed tomography (pCT) is presented. In this approach, protons are not tracked one-by-one but a beam of particles is considered instead. The elements of the pCT reconstruction problem (residual energy and path) are redefined on the basis of this new approach. An analytical image reconstruction algorithm applicable to this scenario is also proposed. Methods: The pencil beam (PB) and its propagation in matter were modeled by making use of the generalization of the Fermi–Eyges theory to account for multiple Coulomb scattering (MCS). This model was integrated into the pCT reconstruction problem, allowing the definition of the mean beam path concept similar to the most likely path (MLP) used in the single-particle approach. A numerical validation of the model was performed. The algorithm of filtered backprojection along MLPs was adapted to the beam-by-beam approach. The acquisition of a perfect proton scan was simulated and the data were used to reconstruct images of the relative stopping power of the phantom with the single-proton and beam-by-beam approaches. The resulting images were compared in a qualitative way. Results: The parameters of the modeled PB (mean and spread) were compared to Monte Carlo results in order to validate the model. For a water target, good agreement was found for the mean value of the distributions. As far as the spread is concerned, depth-dependent discrepancies as large as 2%–3% were found. For a heterogeneous phantom, discrepancies in the distribution spread ranged from 6% to 8%. The image reconstructed with the beam-by-beam approach showed a high level of noise compared to the one reconstructed with the classical approach. Conclusions: The PB approach to proton imaging may allow technical challenges imposed by the current proton-by-proton method to be overcome. In this framework, an analytical algorithm is proposed. Further work will involve a detailed study of the performances and limitations of

  20. Beam standardization of X radiation in computed tomography

    International Nuclear Information System (INIS)

    The ionization chamber used in dosimetric procedures in computed tomography beams (CT), is a cylindrical chamber, unsealed, with the sensitive length between 10 and 15 cm, named pencil ionization chamber. Because the doses involved in CT procedures are higher s than those in the procedures in radiology, it is very important to ensure the appropriate calibration of pencil ionization chambers and thus the accuracy of Dosimetric procedures. Recently, only the Calibration Laboratory, from Institute de Pesquisas Energeticas e Nucleares, had standards fields of conventional radiodiagnostic, but not arrived to include the energy range used in CT. In this work, will be shown the results obtained in standard field of radiodiagnostic - all qualities of radiodiagnostic of series RQR (direct beam) and RQA (attenuated beam) described in IEC 61267 norm - in an industrial X-ray equipment of the Calibration Laboratory. The recommended qualities for the calibration of TC chambers are the qualities RQA9 and RQR9. The other qualities will be used for calibration of other radiodiagnostic dosimeters and also for a larger study of the energy dependence of the pencil ionization chambers

  1. 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.

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

    OpenAIRE

    Jaju PP; Jaju SP

    2014-01-01

    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 an...

  3. SADMFR Guidelines for the Use of Cone-Beam Computed Tomography/Digital Volume Tomography

    OpenAIRE

    Dula, Karl; Benic, Goran I; Bornstein, Michael; Dagassan-Berndt, Dorothea; Filippi, Andreas; Hicklin, Stefan; Kissling-Jeger, Franziska; Luebbers, Heinz-Theo; Sculean, Anton; Sequeira-Byron, Patrick; Walter, Clemens; Zehnder, Matthias

    2015-01-01

    In 2011, the first consensus conference on guidelines for the use of cone-beam computed tomography (CBCT) was convened by the Swiss Society of Dentomaxillofacial Radiology (SGDMFR). This conference covered topics of oral and maxillofacial surgery, temporomandibular joint dysfunctions and disorders, and orthodontics. In 2014, a second consensus conference was convened on guidelines for the use of CBCT in endodontics, periodontology, reconstructive dentistry and pediatric dentistry. The guideli...

  4. Effective dose range for dental cone beam computed tomography scanners

    International Nuclear Information System (INIS)

    Objective: To estimate the absorbed organ dose and effective dose for a wide range of cone beam computed tomography scanners, using different exposure protocols and geometries. Materials and methods: Two Alderson Radiation Therapy anthropomorphic phantoms were loaded with LiF detectors (TLD-100 and TLD-100H) which were evenly distributed throughout the head and neck, covering all radiosensitive organs. Measurements were performed on 14 CBCT devices: 3D Accuitomo 170, Galileos Comfort, i-CAT Next Generation, Iluma Elite, Kodak 9000 3D, Kodak 9500, NewTom VG, NewTom VGi, Pax-Uni3D, Picasso Trio, ProMax 3D, Scanora 3D, SkyView, Veraviewepocs 3D. Effective dose was calculated using the ICRP 103 (2007) tissue weighting factors. Results: Effective dose ranged between 19 and 368 μSv. The largest contributions to the effective dose were from the remainder tissues (37%), salivary glands (24%), and thyroid gland (21%). For all organs, there was a wide range of measured values apparent, due to differences in exposure factors, diameter and height of the primary beam, and positioning of the beam relative to the radiosensitive organs. Conclusions: The effective dose for different CBCT devices showed a 20-fold range. The results show that a distinction is needed between small-, medium-, and large-field CBCT scanners and protocols, as they are applied to different indication groups, the dose received being strongly related to field size. Furthermore, the dose should always be considered relative to technical and diagnostic image quality, seeing that image quality requirements also differ for patient groups. The results from the current study indicate that the optimisation of dose should be performed by an appropriate selection of exposure parameters and field size, depending on the diagnostic requirements.

  5. Cone beam computed tomography findings of impacted upper canines

    International Nuclear Information System (INIS)

    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.

  6. 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.

  7. 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.

  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. Sparse-view proton computed tomography using modulated proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jiseoc; Kim, Changhwan; Cho, Seungryong, E-mail: scho@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejon 305-701 (Korea, Republic of); Min, Byungjun [Department of Radiation Oncology, Kangbuk Samsung Hospital, 110–746 (Korea, Republic of); Kwak, Jungwon [Department of Radiation Oncology, Asan Medical Center, 138–736 (Korea, Republic of); Park, Seyjoon; Lee, Se Byeong [Proton Therapy Center, National Cancer Center, 410–769 (Korea, Republic of); Park, Sungyong [Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan 48532 (United States)

    2015-02-15

    Purpose: Proton imaging that uses a modulated proton beam and an intensity detector allows a relatively fast image acquisition compared to the imaging approach based on a trajectory tracking detector. In addition, it requires a relatively simple implementation in a conventional proton therapy equipment. The model of geometric straight ray assumed in conventional computed tomography (CT) image reconstruction is however challenged by multiple-Coulomb scattering and energy straggling in the proton imaging. Radiation dose to the patient is another important issue that has to be taken care of for practical applications. In this work, the authors have investigated iterative image reconstructions after a deconvolution of the sparsely view-sampled data to address these issues in proton CT. Methods: Proton projection images were acquired using the modulated proton beams and the EBT2 film as an intensity detector. Four electron-density cylinders representing normal soft tissues and bone were used as imaged object and scanned at 40 views that are equally separated over 360°. Digitized film images were converted to water-equivalent thickness by use of an empirically derived conversion curve. For improving the image quality, a deconvolution-based image deblurring with an empirically acquired point spread function was employed. They have implemented iterative image reconstruction algorithms such as adaptive steepest descent-projection onto convex sets (ASD-POCS), superiorization method–projection onto convex sets (SM-POCS), superiorization method–expectation maximization (SM-EM), and expectation maximization-total variation minimization (EM-TV). Performance of the four image reconstruction algorithms was analyzed and compared quantitatively via contrast-to-noise ratio (CNR) and root-mean-square-error (RMSE). Results: Objects of higher electron density have been reconstructed more accurately than those of lower density objects. The bone, for example, has been reconstructed

  10. Trends in maxillofacial cone-beam computed tomography usage

    International Nuclear Information System (INIS)

    Cone-beam computed tomography (CBCT) is making inroads into dental practice worldwide, both in terms of adding the third dimension to diagnosis, and also in terms of enabling image-guided treatment strategies. This article reports trends in the early referral pattern of patients to a CBCT facility in the United States. With institutional review board approval, a retrospective study was made of sequential CBCT radiographic reports made by a specialist oral and maxillofacial radiology service from May 2004 through January 2006 (n=329). Demographic and referral data were extracted from the reports. Descriptive statistics identified referral patterns, trends, and indications for CBCT. Comparisons were made with the Rogers' Product Innovation Adoption curve. The mean age of referred patients was 45±21 years, and there was a predominance of women (62%). Oral and maxillofacial surgeons (51%) and periodontology specialists (17%) made most patient referrals. The listed reasons for CBCT referrals were dental implant planning (40%), suspected surgical pathology (24%), and temporomandibular joint analysis (16%). Other uses included planning extraction of impacted teeth and orthodontic assessment. Over the period of the study, the numbers of pathology diagnosis cases remained relatively constant, while adoption of CBCT for dental implant planning followed closely the first three stages of the Rogers' Product Innovation Adoption curve. Alongside this increased CBCT adoption for dental implant planning, there was an associated increased demand for use of Digital Imaging and Communications in Medicine (DICOM) image sets for laser modeling and provision of surgical guides. Diagnosis will probably remain a constant source of referral for CBCT examination by oral and maxillofacial radiologists. Nevertheless, more specialized applications such as laser-guided model fabrication and image-guided surgery are expanding indications for CBCT referrals by dentists and also expanding the

  11. Positioning variation analysis using Cone Beam Computed Tomography volumetric images

    International Nuclear Information System (INIS)

    Radiotherapy is one of the main treatment modalities of malignancies, either associated with other techniques or not. The successful use of radiation depends on several factors, such as the choice of treatment technique, dosimetric accuracy and geometric precision. The movement of internal organs plays a role quite significant in the calculation of setup margins, but during treatment, the most important variation is the patient’s positioning error. This study evaluated the geometric accuracy in positioning patients with anal canal, prostate, and head and neck cancer, who were treated at ICESP. Cone Beam Computed Tomography (CBCT) images of 40 patients were used, totalizing 224 images. For every CBCT image, the displacement was calculated through the fusion between the images acquired before the treatment and CT images obtained in the simulation.The average deviation was 0.24±0.10 cm to the left-right direction, 0.21±0.12 cm in the anterior-posterior and 0.30±0.18 cm in the superior-inferior direction for cases of anal canal; 0.20±0.10 cm in the left-right, 0.20±0.10 cm in the anterior-posterior and 0.23±0.11 cm in superior-inferior direction for prostate treatments; and 0.11±0.07 cm in the left-right, 0.13±0.06 cm in the anterior-posterior and 0.15±0.10 cm in superior-inferior direction for the treatment of head and neck. The results found were within the predicted PTV margins used at the Institution. (author)

  12. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    International Nuclear Information System (INIS)

    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

  13. Assessment of vertical fracture using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Moudi, Ehsan; Madani, Zahrasadat; Alhavaz, Abdolhamid; Bijani, Ali [Dental Material Research Center, Dental School, Babol University of Medical Sciences, Babol, (Korea, Republic of); Bagheri, Mohammad [Social Determinants of Health Research Center, Babol University of Medical Sciences, Babol (Korea, Republic of)

    2014-03-15

    The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) in the diagnosis of vertical root fractures in a tooth with gutta-percha and prefabricated posts. This study selected 96 extracted molar and premolar teeth of the mandible. These teeth were divided into six groups as follows: Groups A, B, and C consisted of teeth with vertical root fractures, and groups D, E, and F had teeth without vertical root fractures; groups A and D had teeth with gutta-percha and prefabricated posts; groups B and E had teeth with gutta-percha but without prefabricated posts, and groups C and F had teeth without gutta-percha or prefabricated posts. Then, the CBCT scans were obtained and examined by three oral and maxillofacial radiologists in order to determine the presence of vertical root fractures. The data were analyzed using IBM SPSS 20.0 (IBM Corp., Armonk, NY, USA). The kappa coefficient was 0.875 ± 0.049. Groups A and D showed a sensitivity of 81% and a specificity of 100%; groups E and B, a sensitivity of 94% and a specificity of 100%; and groups C and F, a sensitivity of 88% and a specificity of 100%. The CBCT scans revealed a high accuracy in the diagnosis of vertical root fractures; the accuracy did not decrease in the presence of gutta-percha. The presence of prefabricated posts also had little effect on the accuracy of the system, which was, of course, not statistically significant.

  14. 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.

  15. Beam Hardening Artifacts: Comparison between Two Cone Beam Computed Tomography Scanners

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2012-04-01

    Full Text Available Background and aims. At present, cone beam computed tomography (CBCT has become a substitute for computed tomography (CT in dental procedures. The metallic materials used in dentistry can produce artifacts due to the beam hardening phenomenon. These artifacts decrease the quality of images. In the present study, the number of artifacts as a result of beam hardening in the images of dental implants was compared between two NewTom VG and Planmeca Promax 3D Max CBCT machines. Materials and methods. An implant drilling model was used in the present study. The implants (Dentis were placed in the canine, premolar and molar areas. Scanning procedures were carried out by two CBCT machines. The corresponding sections (coronal and axial of the implants were evaluated by two radiologists. The number of artifacts in each image was determined using the scale provided. Mann-Whitney U test was used for two-by-two comparisons at a significance level of P<0.05. Results. There were statistically significant differences in beam hardening artifacts in axial and coronal sections between the two x-ray machines (P<0.001, with a higher quality in the images produced by the NewTom VG. Conclusion. Given the higher quality of the images produced by the NewTom VG x-ray machine, it is recommended for imaging of patients with extensive restorations, multiple prostheses or previous implant treatments.

  16. Evaluation of enamel pearls by cone-beam computed tomography (CBCT)

    OpenAIRE

    AKGÜL, Nilgün; Caglayan, Fatma; Durna, Nurhan; Sümbüllü, Muhammed A.; Akgül, Hayati M.; Durna, Dogan

    2012-01-01

    Objective: The aim of this study was to evaluate the frequency of enamel pearls according to population, sex and tooth groups on Cone-Beam Computed Tomography (CBCT) or Dental Volumetric Tomography (DVT) scans of patients, retrospectively. Study Design: In this study, 15185 teeth belonging to 768 patients, 430 female and 338 male, was performed cross-sectional examination by CBCT. The volumetric Computed Tomography used in the study is Newton FP based on flat-panel. The data were analyzed wit...

  17. Rotational artifacts in on-board cone beam computed tomography

    Science.gov (United States)

    Ali, E. S. M.; Webb, R.; Nyiri, B. J.

    2015-02-01

    Rotational artifacts in image guidance systems lead to registration errors that affect non-isocentric treatments and dose to off-axis organs-at-risk. This study investigates a rotational artifact in the images acquired with the on-board cone beam computed tomography system XVI (Elekta, Stockholm, Sweden). The goals of the study are to identify the cause of the artifact, to characterize its dependence on other quantities, and to investigate possible solutions. A 30 cm diameter cylindrical phantom is used to acquire clockwise and counterclockwise scans at five speeds (120 to 360 deg min-1) on six Elekta linear accelerators from three generations (MLCi, MLCi2 and Agility). Additional scans are acquired with different pulse widths and focal spot sizes for the same mAs. Image quality is evaluated using a common phantom with an in-house three dimensional contrast transfer function attachment. A robust, operator-independent analysis is developed which quantifies rotational artifacts with 0.02° accuracy and imaging system delays with 3 ms accuracy. Results show that the artifact is caused by mislabelling of the projections with a lagging angle due to various imaging system delays. For the most clinically used scan speed (360 deg min-1), the artifact is ˜0.5°, which corresponds to ˜0.25° error per scan direction with the standard Elekta procedure for angle calibration. This leads to a 0.5 mm registration error at 11 cm off-center. The artifact increases linearly with scan speed, indicating that the system delay is independent of scan speed. For the most commonly used pulse width of 40 ms, this delay is 34 ± 1 ms, part of which is half the pulse width. Results are consistent among the three linac generations. A software solution that corrects the angles of individual projections is shown to eliminate the rotational error for all scan speeds and directions. Until such a solution is available from the manufacturer, three clinical solutions are presented, which reduce the

  18. Rotational artifacts in on-board cone beam computed tomography

    International Nuclear Information System (INIS)

    Rotational artifacts in image guidance systems lead to registration errors that affect non-isocentric treatments and dose to off-axis organs-at-risk. This study investigates a rotational artifact in the images acquired with the on-board cone beam computed tomography system XVI (Elekta, Stockholm, Sweden). The goals of the study are to identify the cause of the artifact, to characterize its dependence on other quantities, and to investigate possible solutions. A 30 cm diameter cylindrical phantom is used to acquire clockwise and counterclockwise scans at five speeds (120 to 360 deg min−1) on six Elekta linear accelerators from three generations (MLCi, MLCi2 and Agility). Additional scans are acquired with different pulse widths and focal spot sizes for the same mAs. Image quality is evaluated using a common phantom with an in-house three dimensional contrast transfer function attachment. A robust, operator-independent analysis is developed which quantifies rotational artifacts with 0.02° accuracy and imaging system delays with 3 ms accuracy. Results show that the artifact is caused by mislabelling of the projections with a lagging angle due to various imaging system delays. For the most clinically used scan speed (360 deg min−1), the artifact is ∼0.5°, which corresponds to ∼0.25° error per scan direction with the standard Elekta procedure for angle calibration. This leads to a 0.5 mm registration error at 11 cm off-center. The artifact increases linearly with scan speed, indicating that the system delay is independent of scan speed. For the most commonly used pulse width of 40 ms, this delay is 34 ± 1 ms, part of which is half the pulse width. Results are consistent among the three linac generations. A software solution that corrects the angles of individual projections is shown to eliminate the rotational error for all scan speeds and directions. Until such a solution is available from the manufacturer, three clinical solutions are

  19. Liabilities and risks of using cone beam computed tomography.

    Science.gov (United States)

    Friedland, Bernard; Miles, Dale A

    2014-07-01

    The use of conebeam computed tomography (CBCT) carries with it medicolegal risks of which the practitioner should be aware. These include licensing and malpractice liability concerns. A practitioner who intends to take and/or use CBCT scans should seek advice from his malpractice carrier before doing so. All scans should be read by someone competent to interpret them. Using the services of an out-of-state radiologist to read scans poses its own set of risks. Consultation with a malpractice carrier and dental boards is advisable in this situation. PMID:24993928

  20. 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

  1. Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2009-12-01

    Full Text Available "nBackground and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT and computed tomography (CT."nMaterials and Methods: Thermoluminescent dosimeters (TLD were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ."nResults: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin to 0.308 mGY (submandibular gland, linear tomography ranged from 0.048 mGY (Lens to 0.510 mGY (submandibular gland,CBCT ranged from 0.322 mGY (thyroid glad to 1.144 mGY (Parotid gland and in CT ranged from 2.495 mGY (sublingual gland to 3.424 mGY (submandibular gland. Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT."nConclusion: For obtaining 3-dimensional (3D information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.

  2. 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.

  3. SADMFR Guidelines for the Use of Cone-Beam Computed Tomography/Digital Volume Tomography.

    Science.gov (United States)

    Dula, Karl; Benic, Goran I; Bornstein, Michael; Dagassan-Berndt, Dorothea; Filippi, Andreas; Hicklin, Stefan; Kissling-Jeger, Franziska; Luebbers, Heinz-Theo; Sculean, Anton; Sequeira-Byron, Patrick; Walter, Clemens; Zehnder, Matthias

    2015-01-01

    In 2011, the first consensus conference on guidelines for the use of cone-beam computed tomography (CBCT) was convened by the Swiss Society of Dentomaxillofacial Radiology (SGDMFR). This conference covered topics of oral and maxillofacial surgery, temporomandibular joint dysfunctions and disorders, and orthodontics. In 2014, a second consensus conference was convened on guidelines for the use of CBCT in endodontics, periodontology, reconstructive dentistry and pediatric dentistry. The guidelines are intended for all dentists in order to facilitate the decision as to when the use of CBCT is justified. As a rule, the use of CBCT is considered restrictive, since radiation protection reasons do not allow its routine use. CBCT should therefore be reserved for complex cases where its application can be expected to provide further information that is relevant to the choice of therapy. In periodontology, sufficient information is usually available from clinical examination and periapical radiographs; in endodontics alternative methods can often be used instead of CBCT; and for implant patients undergoing reconstructive dentistry, CT is of interest for the workflow from implant planning to the superstructure. For pediatric dentistry no application of CBCT is seen for caries diagnosis. PMID:26399521

  4. Estimation of computed tomography dose index in cone beam computed tomography: MOSFET measurements and Monte Carlo simulations.

    Science.gov (United States)

    Kim, Sangroh; Yoshizumi, Terry; Toncheva, Greta; Yoo, Sua; Yin, Fang-Fang; Frush, Donald

    2010-05-01

    To address the lack of accurate dose estimation method in cone beam computed tomography (CBCT), we performed point dose metal oxide semiconductor field-effect transistor (MOSFET) measurements and Monte Carlo (MC) simulations. A Varian On-Board Imager (OBI) was employed to measure point doses in the polymethyl methacrylate (PMMA) CT phantoms with MOSFETs for standard and low dose modes. A MC model of the OBI x-ray tube was developed using BEAMnrc/EGSnrc MC system and validated by the half value layer, x-ray spectrum and lateral and depth dose profiles. We compared the weighted computed tomography dose index (CTDIw) between MOSFET measurements and MC simulations. The CTDIw was found to be 8.39 cGy for the head scan and 4.58 cGy for the body scan from the MOSFET measurements in standard dose mode, and 1.89 cGy for the head and 1.11 cGy for the body in low dose mode, respectively. The CTDIw from MC compared well to the MOSFET measurements within 5% differences. In conclusion, a MC model for Varian CBCT has been established and this approach may be easily extended from the CBCT geometry to multi-detector CT geometry. PMID:20386198

  5. Registration-based Reconstruction of Four-dimensional Cone Beam Computed Tomography

    DEFF Research Database (Denmark)

    Christoffersen, Christian; Hansen, David Christoffer; Poulsen, Per Rugaard; Sørensen, Thomas Sangild

    2013-01-01

    We present a new method for reconstruction of four-dimensional (4D) cone beam computed tomography from an undersampled set of X-ray projections. The novelty of the proposed method lies in utilizing optical flow based registration to facilitate that each temporal phase is reconstructed from the full...

  6. 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

  7. Movement of the patient and the cone beam computed tomography scanner: objectives and possible solutions

    Czech Academy of Sciences Publication Activity Database

    Hanzelka, T.; Dušek, J.; Ocásek, F.; Kučera, J.; Šedý, Jiří; Beneš, J.; Pavlíková, G.; Foltán, R.

    2013-01-01

    Roč. 116, č. 6 (2013), s. 769-773. ISSN 2212-4403 Institutional support: RVO:67985823 Keywords : cone beam computed tomography * movement artifacts * dry-run scan Subject RIV: ED - Physiology Impact factor: 1.265, year: 2013

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

    OpenAIRE

    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.

  9. 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.

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

    Science.gov (United States)

    Strindberg, Jerker Edén; Hol, Caroline; Torgersen, Gerald; Møystad, Anne; Nilsson, Mats; Hellén-Halme, Kristina

    2015-01-01

    ABSTRACT 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. PMID:26904179

  11. Ultrasonic divergent-beam scanner for time-of-flight tomography with computer evaluation

    International Nuclear Information System (INIS)

    The rotatable ultrasonic divergent-beam scanner is designed for time-of-flight tomography with computer evaluation. With it there can be measured parameters that are of importance for the structure of soft tissues, e.g. time as a function of the velocity distribution along a certain path of flight(the method is analogous to the transaxial X-ray tomography). Moreover it permits to perform the quantitative measurement of two-dimensional velocity distributions and may therefore be applied to serial examinations for detecting cancer of the breast. As computers digital memories as well as analog-digital-hybrid systems are suitable. (ORU)

  12. Use of cone-beam computed tomography in early detection of implant failure.

    Science.gov (United States)

    Yepes, Juan F; Al-Sabbagh, Mohanad

    2015-01-01

    Preimplant planning with complex imaging techniques has long been a recommended practice for assessing the quality and quantity of alveolar bone before dental implant placement. When maxillofacial imaging is necessary, static film or digital images lack the depth and dimension offered by computed tomography. Cone-beam computed tomography (CBCT) offers the dentist not only a radiographic volumetric view of alveolar bone but also a 3-dimensional reconstruction. This article reviews the use of CBCT for assessing implant placement and early detection of failure, and compares the performance of CBCT with that of other imaging modalities in the early detection of implant failure. PMID:25434558

  13. Comparison of the radiation dose from cone beam computed tomography and multidetector computed tomography in examinations of the hand

    International Nuclear Information System (INIS)

    Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand. Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures < 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose. The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT. Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization.

  14. Comparison of Adsorbed Skin Dose Received by Patients in Cone Beam Computed Tomography, Spiral and Conventional Computed Tomography Scanninng

    Directory of Open Access Journals (Sweden)

    Rahimi A

    2011-12-01

    Full Text Available Background and Aims: The evaluation of absorbed dose received by patients could give useful information for radiation risk estimation. This study was performed to compare the entrance skin dose received by patients in cone beam computed tomography (CBCT, conventional and spiral computed tomography (CT.Materials and Methods: In this experimental study, 81 calibrated TLD chips were used. the TLD chips were placed on facial, thyroid and end of sternum skin surface in patients referred for CT of the paranasal sinuses(3 TLD chips for each area to estimate the absorbed dose received by central part of radiation field, thyroid and out of field areas, respectively. The data were analyzed using one-way ANOVA and Tukey tests. Results: The dose delivered to the center of irradiated field was about 0.79±0.09 mGy in CBCT technique compared with 16.31±3.71 and 18.84±4.12 mGy for spiral and conventional CT, respectively. The received dose by the out of field areas was about 54 percent of central area dose. There was statistical significant relationship between the imaging modalities and absorbed dose received by patients (P=0.016. The least absorbed dose was for CBCT and the greatest dose was for conventional CT imaging technique.Conclusion: The dose delivered to central area of irradiated field in conventional and spiral CT imaging modalities was about 24 times greater than of that in CBCT. Also, the highest received dose was for central area of radiated field and the lowest dose was for the out of field areas.

  15. Image-Guided Radiotherapy for Liver Cancer Using Respiratory-Correlated Computed Tomography and Cone-Beam Computed Tomography

    International Nuclear Information System (INIS)

    Purpose: To evaluate a novel four-dimensional (4D) image-guided radiotherapy (IGRT) technique in stereotactic body RT for liver tumors. Methods and Materials: For 11 patients with 13 intrahepatic tumors, a respiratory-correlated 4D computed tomography (CT) scan was acquired at treatment planning. The target was defined using CT series reconstructed at end-inhalation and end-exhalation. The liver was delineated on these two CT series and served as a reference for image guidance. A cone-beam CT scan was acquired after patient positioning; the blurred diaphragm dome was interpreted as a probability density function showing the motion range of the liver. Manual contour matching of the liver structures from the planning 4D CT scan with the cone-beam CT scan was performed. Inter- and intrafractional uncertainties of target position and motion range were evaluated, and interobserver variability of the 4D-IGRT technique was tested. Results: The workflow of 4D-IGRT was successfully practiced in all patients. The absolute error in the liver position and error in relation to the bony anatomy was 8 ± 4 mm and 5 ± 2 mm (three-dimensional vector), respectively. Margins of 4-6 mm were calculated for compensation of the intrafractional drifts of the liver. The motion range of the diaphragm dome was reproducible within 5 mm for 11 of 13 lesions, and the interobserver variability of the 4D-IGRT technique was small (standard deviation, 1.5 mm). In 4 patients, the position of the intrahepatic lesion was directly verified using a mobile in-room CT scanner after application of intravenous contrast. Conclusion: The results of our study have shown that 4D image guidance using liver contour matching between respiratory-correlated CT and cone-beam CT scans increased the accuracy compared with stereotactic positioning and compared with IGRT without consideration of breathing motion

  16. Algorithm Study on Reconstruction of Refractive Angles in Fan Beam Diffraction Enhanced Computed Tomography

    Institute of Scientific and Technical Information of China (English)

    WANG Min; CEN Yu-Wan; ZHU Pei-Ping; HU Xiao-Fang; YU Xiao-Liu

    2008-01-01

    @@ Based on the 360°computing method of refractive angle for parallel beam diffraction enhanced imaging computed tomography(DE-CT)technique,a new algorithm used to calculate the refractive angle for fan-beam DE-CT technique is developed.The refractive index gradient can be obtained by using the new algorithm with projection data of an object in the range of 0-360°.and the new algorithm only needs to set the analyser at half slope position of the rocking curve.

  17. Limited cone-beam computed tomography imaging of the middle ear: a comparison with multislice helical computed tomography

    International Nuclear Information System (INIS)

    Purpose: To determine the applicability of cone-beam computed tomography (CBCT) in otological imaging, and to compare its accuracy with the routinely used multislice helical CT (MSCT) for imaging of the middle- and inner-ear areas. Material and Methods: Thirteen unoperated human cadaver temporal bones were imaged with CBCT and MSCT. Sixteen landmarks of the middle and adjacent inner ear were evaluated and compared for their conspicuity according to a modified Likert scale. Total scores and scores for subgroups including landmarks of specific clinical interest were also compared. Results: No significant differences were found between the imaging techniques or subgroups when scores of individual structures were compared. While the middle ear itself was visible in all cases with CBCT, parts of the inner ear were 'cut off' in four cases due to the limited field of view. For the same reason, the evaluation of the whole mastoid was not possible with CBCT. The cochlear and vestibular aqueducts were not visualized in either CT techniques. The contrast-to-noise ratio was more than 50% lower in CBCT than in MSCT, but still adequate for diagnostic task. Conclusion: CBCT proved to be at least as accurate as routinely used MSCT in revealing the clinically and surgically important middle-ear structures. The results show that high-quality imaging of the middle ear is possible with the current CBCT device

  18. Limited cone-beam computed tomography imaging of the middle ear: a comparison with multislice helical computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Peltonen, L.I.; Aarnisalo, A.A.; Kortesniemi, M.K.; Suomalainen, A.; Jero, J.; Robinson, S. [Dept. of Otorhinolaryngology and Dept. of Radiology, Helsinki Univ. Central Hospital (Finland)

    2007-02-15

    Purpose: To determine the applicability of cone-beam computed tomography (CBCT) in otological imaging, and to compare its accuracy with the routinely used multislice helical CT (MSCT) for imaging of the middle- and inner-ear areas. Material and Methods: Thirteen unoperated human cadaver temporal bones were imaged with CBCT and MSCT. Sixteen landmarks of the middle and adjacent inner ear were evaluated and compared for their conspicuity according to a modified Likert scale. Total scores and scores for subgroups including landmarks of specific clinical interest were also compared. Results: No significant differences were found between the imaging techniques or subgroups when scores of individual structures were compared. While the middle ear itself was visible in all cases with CBCT, parts of the inner ear were 'cut off' in four cases due to the limited field of view. For the same reason, the evaluation of the whole mastoid was not possible with CBCT. The cochlear and vestibular aqueducts were not visualized in either CT techniques. The contrast-to-noise ratio was more than 50% lower in CBCT than in MSCT, but still adequate for diagnostic task. Conclusion: CBCT proved to be at least as accurate as routinely used MSCT in revealing the clinically and surgically important middle-ear structures. The results show that high-quality imaging of the middle ear is possible with the current CBCT device.

  19. Cone beam computed tomography and intraoral radiography for diagnosis of dental abnormalities in dogs and cats

    International Nuclear Information System (INIS)

    The development of veterinary dentistry has substantially improved the ability to diagnose canine and feline dental abnormalities. Consequently, examinations previously performed only on humans are now available for small animals, thus improving the diagnostic quality. This has increased the need for technical qualification of veterinary professionals and increased technological investments. This study evaluated the use of cone beam computed tomography and intraoral radiography as complementary exams for diagnosing dental abnormalities in dogs and cats. Cone beam computed tomography was provided faster image acquisition with high image quality, was associated with low ionizing radiation levels, enabled image editing, and reduced the exam duration. Our results showed that radiography was an effective method for dental radiographic examination with low cost and fast execution times, and can be performed during surgical procedures

  20. Cone beam computed tomography in veterinary dentistry: description and standardization of the technique

    International Nuclear Information System (INIS)

    Eleven dogs and four cats with buccodental alterations, treated in the Centro Veterinario do Gama, in Brasilia, DF, Brazil, were submitted to cone beam computed tomography. The exams were carried out in a i-CAT tomograph, using for image acquisition six centimeters height, 40 seconds time, 0.2 voxel, 120 kilovolts and 46.72 milli amperes per second. The ideal positioning of the animal for the exam was also determined in this study and it proved to be fundamental for successful examination, which required a simple and safe anesthetic protocol due to the relatively short period of time necessary to obtain the images. Several alterations and diseases were identified with accurate imaging, demonstrating that cone beam computed tomography is a safe, accessible and feasible imaging method which could be included in the small animal dentistry routine diagnosis. (author)

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

    International Nuclear Information System (INIS)

    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

  2. Cracked Tooth: A Report of Two Cases and Role of Cone Beam Computed Tomography in Diagnosis

    Directory of Open Access Journals (Sweden)

    Pishipati Vinayak Kalyan Chakravarthy

    2012-01-01

    Full Text Available Cracked tooth is a distinct type of longitudinal tooth fracture which occurs very commonly and its diagnosis can be challenging. This type of fracture tends to grow and change over time. Clinical diagnosis is difficult because the signs and symptoms are variable or nonspecific and may even resemble post-treatment disease following root canal treatment or periodontal disease. This variety and unpredictability make the cracked tooth a challenging diagnostic entity. The use of cone beam computed tomography (CBCT in diagnosis of complex endodontic cases has been well documented in the literature. In this paper we present two cases of cracked tooth and emphasise on the timely use of cone beam computed tomography as an aid in diagnosis and as a prognostic determinant.

  3. A Rare Presentation of Bilateral Maxillary Dens Invaginatus Diagnosed Using Cone Beam Computed Tomography

    OpenAIRE

    Sainath Dinapadu; Swathi Aravelli; Srikanth Pasari; Narender Reddy Marukala

    2013-01-01

    Dens invaginatus is a developmental variation in the formation of a tooth that causes changes in the internal anatomy of the tooth. The presence of double dens invaginatus is extremely rare. Understanding the type, extension, and complex morphology of dens invaginatus is essential. Diagnosis of this condition using conventional radiographic techniques is not easy. Advanced imaging techniques, such as cone beam computed tomography (CBCT) are very helpful in diagnosis of these complex anatomic ...

  4. Unusual bilateral dentigerous cysts in a nonsyndromic patient assessed by cone beam computed tomography

    OpenAIRE

    Thais Sumie Imada; V. Tieghi Neto; G. F. Bernini; Silva Santos, P. S.; Rubira-Bullen, I. R. F.; D. Bravo-Calderon; Oliveira, D.T.; E. S. Goncales

    2014-01-01

    In the absence of syndromes, bilateral dentigerous cysts (DC) located on the jaws are unusual. In English based language literature review, we only found eight reports of nonsyndromic bilateral dentigerous cyst associated with mandibular third molars. Therefore, we report the unusual occurrence of sizable nonsyndromic bilateral DC associated with mandibular impacted third molars in a 42-year-old Caucasian woman. The lesions were assessed by cone beam computed tomography (CBCT) the right lesio...

  5. Reasons of cone-beam computed tomography examination requests in a dental faculty

    OpenAIRE

    Akarslan, Zühre; Peker, İlkay

    2015-01-01

    OBJECTIVE: Cone-beam computed tomography (CBCT) is a radiographic technique that allows the three-dimensional visualization of the dental and maxillofacial tissues. In recent years, the use of this technique in our country has been increasing continuously. The aim of this study was to assess the reasons and distribution of the CBCT requests in a Dentomaxillofacial Radiology department of a dental faculty.MATERIALS AND METHOD: CBCT request forms belonging to 1087 patients attending the Dentoma...

  6. Versatility of the cone beam computed tomography in oral surgery: an overview

    OpenAIRE

    Kishan G. Panicker; Anuroopa Pudukulangara Nair; Bipin Chandra Reddy

    2011-01-01

    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 posterio...

  7. Rare appearance of an odontogenic myxoma in cone-beam computed tomography: a case report

    OpenAIRE

    Dabbaghi, Arash; Nikkerdar, Nafiseh; Bayati, Soheyla; Golshah, Amin

    2016-01-01

    Odontogenic myxoma (OM) is an infiltrative benign bone tumor that occurs almost exclusively in the facial skeleton. The radiographic characteristics of odontogenic myxoma may produce several patterns, making diagnosis difficult. Cone-beam computed tomography (CBCT) may prove extremely useful in clarifying the intraosseous extent of the tumor and its effects on surrounding structures. Here, we report a case of odontogenic myxoma of the mandible in a 27-year-old female. The patient exhibited a ...

  8. Evaluation of radiation dose and image quality for the Varian cone beam computed tomography system

    OpenAIRE

    Kwong, DLW; Cheng, HCY; Wu, VWC; Liu, ESF

    2011-01-01

    Purpose: To compare the image quality and dosimetry on the Varian cone beam computed tomography (CBCT) system between software Version 1.4.13 and Version 1.4.11 (referred to as "new" and "old" protocols, respectively, in the following text). This study investigated organ absorbed dose, total effective dose, and image quality of the CBCT system for the head-and-neck and pelvic regions. Methods and Materials: A calibrated Farmer chamber and two standard cylindrical Perspex CT dosimetry phantoms...

  9. Assessment of the relationship between the maxillary molars and adjacent structures using cone beam computed tomography

    OpenAIRE

    Jung, Yun-Hoa; Cho, Bong-Hae

    2012-01-01

    Purpose 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. Materials and Methods The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars...

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

    OpenAIRE

    Rangel, Frits A.; Maal, Thomas J. J.; Stefaan J. Bergé; Anne Marie Kuijpers-Jagtman

    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 reported methods have drawbacks. The aim of this feasibility study is to present a new simplified method to integrate digital dental casts into CBCT scans. In a patient scheduled for orthognathic ...

  11. The Applications of Cone-Beam Computed Tomography in Endodontics: A Review of Literature

    OpenAIRE

    Kiarudi, Amir Hosein; Eghbal, Mohammad Jafar; Safi, Yaser; Aghdasi, Mohammad Mehdi; Fazlyab, Mahta

    2014-01-01

    By producing undistorted three-dimensional images of the area under examination, cone-beam computed tomography (CBCT) systems have met many of the limitations of conventional radiography. These systems produce images with small field of view at low radiation doses with adequate spatial resolution that are suitable for many applications in endodontics from diagnosis to treatment and follow-up. This review article comprehensively assembles all the data from literature regarding the potential ap...

  12. The impact of cone beam computed tomography on the choice of endodontic diagnosis

    OpenAIRE

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

    2015-01-01

    Aim To determine whether the outcome of cone beam computed tomography (CBCT) examinations performed in accordance with the European Commission guidelines in a clinical setting has an impact on choosing diagnoses in endodontics. Methodology A prospective observational study was conducted. Fifty-three consecutive patients (81 teeth) from two different endodontic specialist clinics in Sweden were followed. After performing a thorough clinical examination (based on the history, clinical findings,...

  13. 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.

  14. Evaluation of a Cone Beam Computed Tomography Geometry for Image Guided Small Animal Irradiation

    OpenAIRE

    Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

    2015-01-01

    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 (SARRP) developed at Johns Hopkins University employs the pancake geometry where a prone-positioned anima...

  15. Maximal thickness of the normal human pericardium assessed by electron-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Delille, J.P.; Hernigou, A.; Sene, V.; Chatellier, G.; Boudeville, J.C.; Challande, P.; Plainfosse, M.C. [Service de Radiologie Centrale, Hopital Broussais, Paris (France)

    1999-08-01

    The purpose of this study was to determine the maximal value of normal pericardial thickness with an electron-beam computed tomography unit allowing fast scan times of 100 ms to reduce cardiac motion artifacts. Electron-beam computed tomography was performed in 260 patients with hypercholesterolemia and/or hypertension, as these pathologies have no effect on pericardial thickness. The pixel size was 0.5 mm. Measurements could be performed in front of the right ventricle, the right atrioventricular groove, the right atrium, the left ventricle, and the interventricular groove. Maximal thickness of normal pericardium was defined at the 95th percentile. Inter-observer and intra-observer reproducibility studies were assessed from additional CT scans by the Bland and Altman method [24]. The maximal thickness of the normal pericardium was 2 mm for 95 % of cases. For the reproducibility studies, there was no significant relationship between the inter-observer and intra-observer measurements, but all pericardial thickness measurements were {<=} 1.6 mm. Using electron-beam computed tomography, which assists in decreasing substantially cardiac motion artifacts, the threshold of detection of thickened pericardium is statistically established as being 2 mm for 95 % of the patients with hypercholesterolemia and/or hypertension. However, the spatial resolution available prevents a reproducible measure of the real thickness of thin pericardium. (orig.) With 6 figs., 1 tab., 31 refs.

  16. Maximal thickness of the normal human pericardium assessed by electron-beam computed tomography

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the maximal value of normal pericardial thickness with an electron-beam computed tomography unit allowing fast scan times of 100 ms to reduce cardiac motion artifacts. Electron-beam computed tomography was performed in 260 patients with hypercholesterolemia and/or hypertension, as these pathologies have no effect on pericardial thickness. The pixel size was 0.5 mm. Measurements could be performed in front of the right ventricle, the right atrioventricular groove, the right atrium, the left ventricle, and the interventricular groove. Maximal thickness of normal pericardium was defined at the 95th percentile. Inter-observer and intra-observer reproducibility studies were assessed from additional CT scans by the Bland and Altman method [24]. The maximal thickness of the normal pericardium was 2 mm for 95 % of cases. For the reproducibility studies, there was no significant relationship between the inter-observer and intra-observer measurements, but all pericardial thickness measurements were ≤ 1.6 mm. Using electron-beam computed tomography, which assists in decreasing substantially cardiac motion artifacts, the threshold of detection of thickened pericardium is statistically established as being 2 mm for 95 % of the patients with hypercholesterolemia and/or hypertension. However, the spatial resolution available prevents a reproducible measure of the real thickness of thin pericardium. (orig.)

  17. Performance of three pencil-type ionization chambers (10 cm) in computed tomography standard beams

    Science.gov (United States)

    de Castro, Maysa C.; Xavier, Marcos; Caldas, Linda V. E.

    2016-07-01

    The use of computed tomography (CT) has increased over the years, thus generating a concern about the doses received by patients undergoing this procedure. Therefore, it is necessary to perform routinely beam dosimetry with the use of a pencil-type ionization chamber. This detector is the most utilized in the procedures of quality control tests on this kind of equipment. The objective of this work was to perform some characterization tests in standard CT beams, as the saturation curve, polarity effect, ion collection efficiency and linearity of response, using three ionization chambers, one commercial and two developed at the IPEN.

  18. Quality control and radioprotection in dental cone beam computed tomography - case study

    International Nuclear Information System (INIS)

    The radiological protection in medical and odontologic radiology follows The Order (Portaria) 453/98 of the Ministry of Health, which presents the minimum set of tests for the constancy X-ray equipment. These tests follow the procedures set forth in the Resolution no. 64, the National Agency for Sanitary Vigilance. This work aims to show a study on dental cone beam computed tomography (CBCT), evaluating the physical parameters that influence the performance and image quality and presenting the appropriate tests to this new system. The authors analyzed the tests specific for computed tomography (CT) of the Resolution no. 64, feasibility assessment of them and if their interpretations are compatible with CBCT. Once determined if testing is feasible, compare with those presented in the manual provided by the equipment manufacturer. The CT scanner used was the Mini-Cat Tomography Scanner Xoran Technologies of KAVO. In the study it was verified that four tests could be reproduced in CBCT: noise, accuracy and uniformity in the number of CT of water and spatial resolution. Considering experimental data, the methodology and tolerance of manufacturer for the first two tests were more appropriate. For the uniformity test of the CT number, we recommend using the phantom quality control. Three new tests were suggested to be made in the quality control of the Cone Beam: linearity, artifacts and alignment of the beam. (author)

  19. Quality control and radioprotection in dental cone beam computed tomography - case study

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Ligiane C.N.; Ferreira, Nadya M.P.D., E-mail: lnadya@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    The radiological protection in medical and odontologic radiology follows The Order (Portaria) 453/98 of the Ministry of Health, which presents the minimum set of tests for the constancy X-ray equipment. These tests follow the procedures set forth in the Resolution no. 64, the National Agency for Sanitary Vigilance. This work aims to show a study on dental cone beam computed tomography (CBCT), evaluating the physical parameters that influence the performance and image quality and presenting the appropriate tests to this new system. The authors analyzed the tests specific for computed tomography (CT) of the Resolution no. 64, feasibility assessment of them and if their interpretations are compatible with CBCT. Once determined if testing is feasible, compare with those presented in the manual provided by the equipment manufacturer. The CT scanner used was the Mini-Cat Tomography Scanner Xoran Technologies of KAVO. In the study it was verified that four tests could be reproduced in CBCT: noise, accuracy and uniformity in the number of CT of water and spatial resolution. Considering experimental data, the methodology and tolerance of manufacturer for the first two tests were more appropriate. For the uniformity test of the CT number, we recommend using the phantom quality control. Three new tests were suggested to be made in the quality control of the Cone Beam: linearity, artifacts and alignment of the beam. (author)

  20. Accuracy and reliability of a novel method for fusion of digital dental casts and cone beam computed tomography scans

    OpenAIRE

    Rangel, Frits A.; Maal, Thomas J. J.; Ewald M Bronkhorst; K Hero Breuning; Schols, Jan G. J. H.; Bergé, Stefaan J.; Anne Marie Kuijpers-Jagtman

    2013-01-01

    Several methods have been proposed to integrate digital models into Cone Beam Computed Tomography scans. Since all these methods have some drawbacks such as radiation exposure, soft tissue deformation and time-consuming digital handling processes, we propose a new method to integrate digital dental casts into Cone Beam Computed Tomography scans. Plaster casts of 10 patients were randomly selected and 5 titanium markers were glued to the upper and lower plaster cast. The plaster models were sc...

  1. 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)

  2. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses What is CT (Computed Tomography) of ... of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  3. Computed Tomography (CT) -- Sinuses

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  4. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  5. Electron beam computed tomography and ventilation perfusion scintigraphy in the diagnosis of pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Kettner, Beatrice I.; Sandrock, Dirk; Reisinger, Ingrid; Munz, Dieter L. [Clinic for Nuclear Medicine, Humboldt University of Berlin (Germany); Enzweiler, Christian N.H. [Department of Radiology, Humboldt University of Berlin (Germany)

    2002-05-01

    The purpose of this study, performed in patients with suspected pulmonary embolism (PE), was to compare V/Q scans and electron beam computed tomography (CT) scans on a patient-by-patient and segment-by-segment basis. Both a segment-based and a lobe-based analysis was performed in those patients positive for PE. The diagnosis of PE was assumed on the basis of a mismatch at V/Q scanning or a filling defect in a pulmonary vessel at contrast-enhanced electron beam CT. In 37/45 patients (24 female, 21 male, 58{+-}16 years) with suspected PE, the diagnosis of PE was confirmed or excluded by both modalities, resulting in a correlation of 82% between electron beam CT and V/Q scanning. In the 28 patients positive for PE according to one or both modalities, 504 segments were evaluated. Of these 504 segments, 248 (nearly 50%) showed perfusion defects on V/Q scans, of which only 90 (36%) displayed emboli at electron beam CT. Overall, a total of only 135 of the 504 segments (27%) were abnormal at electron beam CT. More than 50% of the patients with discrepant results did not show an embolus at electron beam CT. It is concluded that there is a good correlation (82%) between V/Q scanning and electron beam CT on a patient-by-patient basis but a markedly less good correlation (62%) in a segment-based analysis. (orig.)

  6. 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.

  7. Cone Beam Computed Tomography for Detection of Intrabony and Furcation Defects

    DEFF Research Database (Denmark)

    Nikolic-Jakoba, Natasa; Spin-Neto, Rubens; Wenzel, Ann

    OBJECTIVES: To make a systematic review assessing the diagnostic efficacy of cone beam computed tomography (CBCT) for the diagnosis of and/or treatment plan for intrabony and furcation defects, using a well-known six-tiered hierarchical model for diagnostic efficacy. METHODS: The MEDLINE, EMBASE......, and Cochrane Library bibliographic databases were searched until August 2015 for studies evaluating CBCT imaging for the diagnosis of and/or treatment plan for intrabony and/or furcation defects. The search strategy was restricted to English language publications using the combination of MeSH terms...

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

    Science.gov (United States)

    Yılmaz, Funda; Kamburoglu, Kıvanç; Yeta, Naz Yakar; Öztan, Meltem Dartar

    2016-07-28

    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, non-diagnosed 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. PMID:27551342

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

    International Nuclear Information System (INIS)

    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.

  10. Experimental study of beam hardening artifacts in photon counting breast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bisogni, M.G.; Del Guerra, A. [Dip. di Fisica, Univ. di Pisa and INFN, Pisa (Italy); Lanconelli, N. [Dip. di Fisica, Univ. di Bologna and INFN, Bologna (Italy); Lauria, A.; Mettivier, G. [Dip. di Scienze Fisiche, Univ. di Napoli Federico II and INFN, Naples (Italy); Montesi, M.C. [Dip. di Scienze Fisiche, Univ. di Napoli Federico II and INFN, Naples (Italy)], E-mail: montesi@na.infn.it; Panetta, D. [Dip. di Fisica, Univ. di Pisa and INFN, Pisa (Italy); Pani, R. [Dip. di Medicina Sperimentale, Univ. La Sapienza and INFN, Rome (Italy); Quattrocchi, M.G. [Dip. di Fisica, Univ. di Pisa and INFN, Pisa (Italy); Randaccio, P. [Dip. di Fisica, Univ. di Cagliari and INFN, Cagliari (Italy); Rosso, V. [Dip. di Fisica, Univ. di Pisa and INFN, Pisa (Italy); Russo, P. [Dip. di Scienze Fisiche, Univ. di Napoli Federico II and INFN, Naples (Italy)

    2007-10-21

    We are implementing an X-ray breast Computed Tomography (CT) system on the gantry of a dedicated single photon emission tomography system for breast Tc-99 imaging. For the breast CT system we investigated the relevance of the beam hardening artifact. We studied the use of a single photon counting silicon pixel detector (0.3 mm thick, 256x256 pixel, 55{mu}m pitch, bump-bonded to the Medipix2 photon counting readout chip) as detector unit in our X-ray CT system. We evaluated the beam hardening 'cupping' artifact using homogeneous PMMA slabs and phantoms up to 14 cm in diameter, used as uncompressed breast tissue phantoms, imaged with a tungsten anode tube at 80 kVp with 4.2 mm Al filtration. For beam hardening evaluation we used a bimodal energy model. The CT data show a 'cupping' artifact going from 4% (4-cm thick material) to 18% (14-cm thick material). This huge artifacts is influenced by the low detection efficiency and the charge sharing effect of the silicon pixel detector.

  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. Computed tomography dose assessment for a 160 mm wide, 320 detector row, cone beam CT scanner

    International Nuclear Information System (INIS)

    Computed tomography (CT) dosimetry should be adapted to the rapid developments in CT technology. Recently a 160 mm wide, 320 detector row, cone beam CT scanner that challenges the existing Computed Tomography Dose Index (CTDI) dosimetry paradigm was introduced. The purpose of this study was to assess dosimetric characteristics of this cone beam scanner, to study the appropriateness of existing CT dose metrics and to suggest a pragmatic approach for CT dosimetry for cone beam scanners. Dose measurements with a small Farmer-type ionization chamber and with 100 mm and 300 mm long pencil ionization chambers were performed free in air to characterize the cone beam. According to the most common dose metric in CT, namely CTDI, measurements were also performed in 150 mm and 350 mm long CT head and CT body dose phantoms with 100 mm and 300 mm long pencil ionization chambers, respectively. To explore effects that cannot be measured with ionization chambers, Monte Carlo (MC) simulations of the dose distribution in 150 mm, 350 mm and 700 mm long CT head and CT body phantoms were performed. To overcome inconsistencies in the definition of CTDI100 for the 160 mm wide cone beam CT scanner, doses were also expressed as the average absorbed dose within the pencil chamber (D-bar100). Measurements free in air revealed excellent correspondence between CTDI300air and D-bar100air, while CTDI100air substantially underestimates CTDI300air. Results of measurements in CT dose phantoms and corresponding MC simulations at centre and peripheral positions were weighted and revealed good agreement between CTDI300w, D-bar100w and CTDI600w, while CTDI100w substantially underestimates CTDI300w. D-bar100w provides a pragmatic metric for characterizing the dose of the 160 mm wide cone beam CT scanner. This quantity can be measured with the widely available 100 mm pencil ionization chamber within 150 mm long CT dose phantoms. CTDI300w measured in 350 mm long CT dose phantoms serves as an appropriate

  13. Asymptomatic radiopaque lesions of the jaws: a radiographic study using cone-beam computed tomography.

    Science.gov (United States)

    Araki, Masao; Matsumoto, Naoyuki; Matsumoto, Kunihito; Ohnishi, Masaaki; Honda, Kazuya; Komiyama, Kazuo

    2011-12-01

    Panoramic radiography and cone-beam computed tomography (CT) were used to analyze asymptomatic radiopaque lesions in the jaw bones and determine the diagnostic relevance of the lesions based on their relationships to teeth and site of origin. One hundred radiopaque lesions detected between 1998 and 2002 were examined by both panoramic radiography and cone-beam CT. On the basis of panoramic radiographs, the region was classified as periapical, body, or edentulous, and the site was classified as molar or premolar. Follow-up data from medical records were available for only 36 of these cases. The study protocol for simultaneous use of cone-beam CT was approved by the ethics review board of our institution. A large majority of radiopaque lesions were observed in premolar and molar sites of the mandible; 60% of lesions were periapical, 24% were in the body, and 16% were in the edentulous region. An interesting type of radiopaque lesion, which we named a pearl shell structure (PSS), was observed on cone-beam CT in 34 of the 100 lesions. The PSS is a distinctive structure, and this finding on cone-beam CT likely represents the start of bone formation before bone sclerosis. PMID:22167028

  14. Asymptomatic radiopaque lesions of the jaws. A radiographic study using cone-beam computed tomography

    International Nuclear Information System (INIS)

    Panoramic radiography and cone-beam computed tomography (CT) were used to analyze asymptomatic radiopaque lesions in the jaw bones and determine the diagnostic relevance of the lesions based on their relationships to teeth and site of origin. One hundred radiopaque lesions detected between 1998 and 2002 were examined by both panoramic radiography and cone-beam CT. On the basis of panoramic radiographs, the region was classified as periapical, body, or edentulous, and the site was classified as molar or premolar. Follow-up data from medical records were available for only 36 of these cases. The study protocol for simultaneous use of cone-beam CT was approved by the ethics review board of our institution. A large majority of radiopaque lesions were observed in premolar and molar sites of the mandible; 60% of lesions were periapical, 24% were in the body, and 16% were in the edentulous region. An interesting type of radiopaque lesion, which we named a pearl shell structure (PSS), was observed on cone-beam CT in 34 of the 100 lesions. The PSS is a distinctive structure, and this finding on cone-beam CT likely represents the start of bone formation before bone sclerosis. (author)

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

    Science.gov (United States)

    Bapst, Blanche; Lagadec, Matthieu; Breguet, Romain; Vilgrain, Valérie; Ronot, Maxime

    2016-01-01

    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. PMID:26178776

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

    International Nuclear Information System (INIS)

    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

  17. 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.

  18. 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.

  19. Effect of beam spectrum on quantitativeness of cold neutron computed tomography

    International Nuclear Information System (INIS)

    In case of radiography by a cold neutron beam having a continuous beam spectrum, neutron attenuation coefficients of many materials decrease with increasing the transmitting path length. As a result, quantitative analyses, such as determining the composition and density of the object quantitatively, with cold neutron computed tomography (CN-CT) has been difficult. In order to improve quantitativeness of CN-CT, we examined two procedures for reducing the effect of the thickness-dependent attenuation coefficient, and confirmed their effectiveness experimentally. One procedure is modifying projected images by using the neutron transmission curve as a kind of calibration curve, which is called the inverse function method. Another, the spectrum-narrowing method, is depressing change of the attenuation coefficient by making the width of the neutron beam spectrum narrower with a neutron filter. Each procedure was demonstrated experimentally to enable quantitative CN-CT. The inverse function method is simple, but it emphasizes noises of the projected image in, especially, the low neutron transmittance region. The spectrum-narrowing method has an advantage of obtaining the simple exponential attenuation property on neutron radiograph, though the longer exposure time was required because of beam intensity loss. (author)

  20. Neutron beam tomography software

    International Nuclear Information System (INIS)

    When a sample is traversed by a neutron beam, inhomogeneities in the sample will cause deflections, and the deflections will permit conclusions to be drawn concerning the location and size of the inhomogeneities. The associated computation is similar to problems in tomography, analogous to X-ray tomography though significantly different in detail. We do not have any point-sample information, but only mean values over short line segments. Since each mean value is derived from a separate neutron counter, the quantity of available data has to be modest; also, since each datum is an integral, its geometric precision is inferior to that of X-ray data. Our software is designed to cope with these difficulties. (orig.)

  1. Capabilities of Cone-Beam Computed Tomography in the Assessment of the Structure of Wrist and Hand Bones

    OpenAIRE

    А.Yu. Vasiliev, PhD, MD; N.N. Blinov, PhD, MD; Е.A. Egorova, PhD, MD; D.V. Makarova; E.G. Gorlycheva; M.O. Dutova

    2013-01-01

    An analysis of the capabilities of cone-beam computed tomography (CBCT) in the assessment of the form and structure of wrist and hand bones was the aim of the research. Cone-beam CT of wrist and hand was conducted in a group of voluntary patients, which included 40 members aged 22- 68 years. Magnetic resonance imaging (МRI) was carried out in 80.0% (n = 32) of cases, multislice computed tomography (MSCT) in 40.0% (n=16) of cases. In 62.5 % (n=25) of cases, digital microfocus radiography on X-...

  2. Effective dose estimates for cone beam computed tomography in interventional radiology

    International Nuclear Information System (INIS)

    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.)

  3. A review of setup error in supine breast radiotherapy using cone-beam computed tomography.

    Science.gov (United States)

    Batumalai, Vikneswary; Holloway, Lois; Delaney, Geoff P

    2016-01-01

    Setup error in breast radiotherapy (RT) measured with 3-dimensional cone-beam computed tomography (CBCT) is becoming more common. The purpose of this study is to review the literature relating to the magnitude of setup error in breast RT measured with CBCT. The different methods of image registration between CBCT and planning computed tomography (CT) scan were also explored. A literature search, not limited by date, was conducted using Medline and Google Scholar with the following key words: breast cancer, RT, setup error, and CBCT. This review includes studies that reported on systematic and random errors, and the methods used when registering CBCT scans with planning CT scan. A total of 11 relevant studies were identified for inclusion in this review. The average magnitude of error is generally less than 5mm across a number of studies reviewed. The common registration methods used when registering CBCT scans with planning CT scan are based on bony anatomy, soft tissue, and surgical clips. No clear relationships between the setup errors detected and methods of registration were observed from this review. Further studies are needed to assess the benefit of CBCT over electronic portal image, as CBCT remains unproven to be of wide benefit in breast RT. PMID:27311516

  4. 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.

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

    International Nuclear Information System (INIS)

    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.

  6. 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.

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

    International Nuclear Information System (INIS)

    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). It was concluded that CBCT improves the ability of predicting the actual implant length and reduces inaccuracy in surgical dental implant planning. (author)

  8. 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.

  9. 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.

  10. Slice image pretreatment for cone-beam computed tomography based on adaptive filter

    International Nuclear Information System (INIS)

    According to the noise properties and the serial slice image characteristics in Cone-Beam Computed Tomography (CBCT) system, a slice image pretreatment for CBCT based on adaptive filter was proposed. The judging criterion for the noise is established firstly. All pixels are classified into two classes: adaptive center weighted modified trimmed mean (ACWMTM) filter is used for the pixels corrupted by Gauss noise and adaptive median (AM) filter is used for the pixels corrupted by impulse noise. In ACWMTM filtering algorithm, the estimated Gauss noise standard deviation in the current slice image with offset window is replaced by the estimated standard deviation in the adjacent slice image to the current with the corresponding window, so the filtering accuracy of the serial images is improved. The pretreatment experiment on CBCT slice images of wax model of hollow turbine blade shows that the method makes a good performance both on eliminating noises and on protecting details. (authors)

  11. 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.

  12. Endodontic management of mandibular first molar with seven canals using cone-beam computed tomography

    Science.gov (United States)

    Banode, Ankur Mahesh; Gade, Vandana; Patil, Sanjay; Gade, Jaykumar

    2016-01-01

    The endodontic treatment of a mandibular molar with aberrant canal configuration can be diagnostically and clinically challenging. Successful endodontic therapy thus depends on the clinician's ability to anticipate and look for these aberrant variations. A mandibular first molar with seven canals represents a rare anatomical variant, particularly when four canals are found in distal root. Based on in vitro studies, its incidence is reported to be between 0.2% and 3%. With the advent of cone-beam computed tomography (CBCT) as an adjunctive diagnostic aid, the determination of root canal anatomy in teeth with complex canal configurations has become more precise. The present case report discusses successful nonsurgical management of radix entomolaris along with middle mesial canal and middle distal canal in mandibular first molar with seven canals (four canals in distal and three in mesial) employing CBCT as an adjunctive diagnostic aid to conventional radiography. PMID:27307680

  13. Computed Tomography (CT) -- Head

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  14. 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

  15. X-ray cone-beam computed tomography: principles, applications, challenges and solutions

    Science.gov (United States)

    Noo, Frederic

    2010-03-01

    In the nineties, x-ray computed tomography, commonly referred to as CT, seemed to be on the track to become old technology, bound to be replaced by more sophisticated techniques such as magnetic resonance imaging, due in particular to the harmful effects of x-ray radiation exposure. Yet, the new century brought with it new technology that allowed a complete change in trends and re-affirmed CT as an essential tool in radiology. For instance, the popularity of CT in 2007 was such that approximately 68.7 million CT examinations were performed in the United States, which was nearly 2.5 times the number of magnetic resonance (MRI) examinations. More than that, CT has expanded beyond its conventional diagnostic role; CT is now used routinely in interventional radiology and also in radiation therapy treatment. The technology advances that allowed the revival of CT are those that made fast, accurate cone-beam data acquisition possible. Nowadays, cone-beam data acquisition allows scanning large volumes with isotropic sub-millimeter spatial resolution in a very fast time, which can be as short as 500ms for cardiac imaging. The principles of cone-beam imaging will be first reviewed. Then a discussion of its applications will be given. Old and new challenges will be presented along the way with current solutions.

  16. A post-reconstruction method to correct cupping artifacts in cone beam breast computed tomography

    International Nuclear Information System (INIS)

    In cone beam breast computed tomography (CT), scattered radiation leads to nonuniform biasing of CT numbers known as a cupping artifact. Besides being visual distractions, cupping artifacts appear as background nonuniformities, which impair efficient gray scale windowing and pose a problem in threshold based volume visualization/segmentation. To overcome this problem, we have developed a background nonuniformity correction method specifically designed for cone beam breast CT. With this technique, the cupping artifact is modeled as an additive background signal profile in the reconstructed breast images. Due to the largely circularly symmetric shape of a typical breast, the additive background signal profile was also assumed to be circularly symmetric. The radial variation of the background signals was estimated by measuring the spatial variation of adipose tissue signals in front view breast images. To extract adipose tissue signals in an automated manner, a signal sampling scheme in polar coordinates and a background trend fitting algorithm were implemented. The background fits compared with targeted adipose tissue signal value (constant throughout the breast volume) to get an additive correction value for each tissue voxel. To test the accuracy, we applied the technique to cone beam CT images of mastectomy specimens. After correction, the images demonstrated significantly improved signal uniformity in both front and side view slices. The reduction of both intraslice and interslice variations in adipose tissue CT numbers supported our observations

  17. Anatomical and Morphological Characterization of the Nasopalatine Canal: A Cone-Beam Computed Tomography Study.

    Science.gov (United States)

    Rodricks, D; Gupta, A; Phulambrikar, T; Singh, S K; Sharma, B K; Agrawal, P

    2016-04-01

    The anterior maxilla, also called pre-maxilla, is an area frequently requiring surgical interventions. Rehabilitation of this area remains a complex restorative challenge. The most prominent anatomical structure within the anterior maxilla is the Nasopalatine Canal. Thorough knowledge about this anatomical structure plays an important role in the successful outcomes of surgical procedures. This retrospective study was done to evaluate the anatomy and morphology of the Nasopalatine Canal using cone-beam computed tomography (CBCT). The study included 125 subjects aged between 15 and 78 years who were divided into the following 5 groups: i) 15-30 years, ii) 30-45 years, iii) 45-60 years, iv) 60-75 years, v) ≥75 years in the Department of Oral Medicine & Radiology, Sri Aurobindo College of Dentistry, Indore, Madhya Pradesh, India from January 2012 to January 2015. Cone-beam computed tomography (CBCT) was performed using a standard exposure and patient positioning protocol. The data of the CBCT images were sliced in three dimensions. Image planes on the three axes (X, Y, and Z) were sequentially analyzed for the location, morphology and dimensions of the Nasopalatine Canal. The correlation of age and gender with all the variables were evaluated. ANOVA and Z-test was used. P value <0.05 was considered statistically significant. Males and females showed significant differences in the length of the canal and anterior bone width in the sagittal sections. Inverted L was identified as a new dimension to the morphological shape of Nasopalatine Canal in central Madhya Pradesh population. The present study highlighted important variability observed in the anatomy and morphology of the Nasopalatine Canal. PMID:27277370

  18. 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.

  19. 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...

  20. 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

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

    NARCIS (Netherlands)

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

    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

  2. Neutron Computed Tomography

    International Nuclear Information System (INIS)

    Computed tomography is a non-destructive testing method which can visualize cross-section of materials based on their nuclear characteristics. In the previous work, X-ray was used as its radiation media. The aim of this experiment was to improve the computed tomography technique using neutron beam. For reconstructing the cross-section image of materials, a filtered back projection was used. Result indicated that a minimum hole shown was 3 mm in diameter using a black and white presentation. While using eight colour levels, a hole of 2 mm in diameter could be seen clearly. It is expected that neutron computed tomography can improve the results of non-destructive testing. (author). 5 refs., 6 figs

  3. 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.

  4. 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.

  5. Determination and comparison of computed tomography quantities in standard beams using standard adult and pediatric phantoms

    International Nuclear Information System (INIS)

    The computed tomography (CT) is a segment of diagnostic radiology that uses higher radiation dose comparing to others fields of conventional radiology. In 2011, for decreasing the uncertainty in the diagnostic radiology beams dosimetry, the International Atomic Energy Agency (IAEA) published an implementation on the Technical Reports Series no. 457 from 2007, which is a code of practice recommending procedures for calibration and dosimetry in diagnostic radiology field. The objective of this study was to compare CT measurements on standards beams using adult and pediatric phantoms. The same procedure was used for two types of phantoms. Measurements were performed on the surface of the phantoms obtaining values of entrance surface air kerma (Ke). Measurements were taken from 100 to 150 kV (RQT 8, 9 and RQT 10), with the center of the simulators positioned at a distance of 100 cm from the focal spot. The values for the CT quantities air kerma index (in free air, CK, and in phantom, CPMMA,C / CPMMA,P) and air kerma length product (PKA) were found. The results were significant and the largest difference between the two phantoms was found for the radiation quality RQT 10. (author)

  6. Planar cone-beam computed tomography with a flat-panel detector

    Science.gov (United States)

    Kim, S. H.; Kim, D. W.; Youn, H.; Kim, D.; Kam, S.; Jeon, H.; Kim, H. K.

    2015-12-01

    For a dedicated x-ray inspection of printed-circuit boards (PCBs), a bench-top planar cone-beam computed tomography (pCT) system with a flat-panel detector has been built in the laboratory. The system adopts the tomosynthesis technique that can produce cross-sectional images parallel to the axis of rotation for a limited angular range. For the optimal operation of the system and further improvement in the next design, we have evaluated imaging performances, such as modulation-transfer function, noise-power spectrum, and noise-equivalent number of quanta. The performances are comparatively evaluated with the coventional cone-beam CT (CBCT) acquisition for various scanning angular ranges, applied tube voltages, and geometrical magnification factors. The pCT scan shows a poorer noise performance than the conventional CBCT scan because of less number of projection views used for reconstruction. However, the pCT shows a better spatial-resolution performance than the CBCT. Because the image noise can be compensated by an elevated exposure level during scanning, the pCT can be a useful modality for the PCB inspection that requires higher spatial-resolution performance.

  7. 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.

  8. Planar cone-beam computed tomography with a flat-panel detector

    International Nuclear Information System (INIS)

    For a dedicated x-ray inspection of printed-circuit boards (PCBs), a bench-top planar cone-beam computed tomography (pCT) system with a flat-panel detector has been built in the laboratory. The system adopts the tomosynthesis technique that can produce cross-sectional images parallel to the axis of rotation for a limited angular range. For the optimal operation of the system and further improvement in the next design, we have evaluated imaging performances, such as modulation-transfer function, noise-power spectrum, and noise-equivalent number of quanta. The performances are comparatively evaluated with the coventional cone-beam CT (CBCT) acquisition for various scanning angular ranges, applied tube voltages, and geometrical magnification factors. The pCT scan shows a poorer noise performance than the conventional CBCT scan because of less number of projection views used for reconstruction. However, the pCT shows a better spatial-resolution performance than the CBCT. Because the image noise can be compensated by an elevated exposure level during scanning, the pCT can be a useful modality for the PCB inspection that requires higher spatial-resolution performance

  9. Determination and comparison of computed tomography quantities in standard beams using standard adult and pediatric phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Elaine Wirney; Potiens, Maria da Penha A., E-mail: ewmartins@ipen.br, E-mail: mppalbu@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The computed tomography (CT) is a segment of diagnostic radiology that uses higher radiation dose comparing to others fields of conventional radiology. In 2011, for decreasing the uncertainty in the diagnostic radiology beams dosimetry, the International Atomic Energy Agency (IAEA) published an implementation on the Technical Reports Series no. 457 from 2007, which is a code of practice recommending procedures for calibration and dosimetry in diagnostic radiology field. The objective of this study was to compare CT measurements on standards beams using adult and pediatric phantoms. The same procedure was used for two types of phantoms. Measurements were performed on the surface of the phantoms obtaining values of entrance surface air kerma (K{sub e}). Measurements were taken from 100 to 150 kV (RQT 8, 9 and RQT 10), with the center of the simulators positioned at a distance of 100 cm from the focal spot. The values for the CT quantities air kerma index (in free air, C{sub K}, and in phantom, C{sub PMMA,C} / C{sub PMMA,P}) and air kerma length product (P{sub KA}) were found. The results were significant and the largest difference between the two phantoms was found for the radiation quality RQT 10. (author)

  10. 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.

  11. In Vitro Detection of Dental Root Fractures with Cone Beam Computed Tomography (CBCT)

    International Nuclear Information System (INIS)

    Since the diagnosis of non-displaced longitudinal fractures present difficulties for the dentist, three-dimensional evaluation is necessary. The aim of this study is to demonstrate the accuracy of cone beam computed tomography (CBCT) in detecting dental root fractures in vitro. An in vitro model consisting of 210 recently extracted human mandibular teeth was used. Root fractures were created by mechanical force. The teeth were placed randomly in the empty dental alveoli of a dry human mandible and 15 different dental arcs were created. Images were taken with a unit Iluma ultra cone-beam CT scanner (Imtec Corporation, Germany). Three dental radiologists separately evaluated the images. According to the fracture types and fracture presence, there was an overall statistically significant agreement between the key and readings. Kappa values for intra observer agreement ranged between 0.705 and 0.804 indicating that each observer gave acceptable ratings for the type and presence of fractures. Detailed information about root fractures may be obtained using CBCT

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

    International Nuclear Information System (INIS)

    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

  13. Intravenous contrast media application using cone-beam computed tomography in a rabbit model

    International Nuclear Information System (INIS)

    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.

  14. 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.

  15. Radiation dose evaluation of dental cone beam computed tomography using an anthropomorphic adult head phantom

    International Nuclear Information System (INIS)

    Dental cone beam computed tomography (CBCT) provides high-resolution tomographic images and has been gradually used in clinical practice. Thus, it is important to examine the amount of radiation dose resulting from dental CBCT examinations. In this study, we developed an in-house anthropomorphic adult head phantom to evaluate the level of effective dose. The anthropomorphic phantom was made of acrylic and filled with plaster to replace the bony tissue. The contour of the head was extracted from a set of adult computed tomography (CT) images. Different combinations of the scanning parameters of CBCT were applied. Thermoluminescent dosimeters (TLDs) were used to measure the absorbed doses at 19 locations in the head and neck regions. The effective doses measured using the proposed phantom at 65, 75, and 85 kVp in the D-mode were 72.23, 100.31, and 134.29 µSv, respectively. In the I-mode, the effective doses were 108.24, 190.99, and 246.48 µSv, respectively. The maximum percent error between the doses measured by the proposed phantom and the Rando phantom was l4.90%. Therefore, the proposed anthropomorphic adult head phantom is applicable for assessing the radiation dose resulting from clinical dental CBCT. - Highlights: • A home-made anthropomorphic adult head phantom was proposed. • The proposed phantom can be easily built with lower price than the standard Rando phantom. • The proposed phantom can be used for evaluating the effective dose during dental CBCT scanning

  16. Quality assessment and enhancement for cone-beam computed tomography in dental imaging

    International Nuclear Information System (INIS)

    Cone-beam CT will become increasingly important in diagnostic imaging modality in the dental practice over the next decade. For dental diagnostic imaging, cone-beam computed tomography (CBCT) system based on large area flat panel imager has been designed and developed for three-dimensional volumetric image. The new CBCT system can provide a 3-D volumetric image during only one circular scanning with relatively short times (20-30 seconds) and requires less radiation dose than that of conventional CT. To reconstruct volumetric image from 2-D projection images, FDK algorithm was employed. The prototype of our CBCT system gives the promising results that can be efficiently diagnosed. This dissertation deals with assessment, enhancement, and optimization for dental cone-beam computed tomography with high performance. A new blur estimation method was proposed, namely model based estimation algorithm. Based on the empirical model of the PSF, an image restoration is applied to radiological images. The accuracy of the PSF estimation under Poisson noise and readout electronic noise is significantly better for the R-L estimator than the Wiener estimator. In the image restoration experiment, the result showed much better improvement in the low and middle range of spatial frequency. Our proposed algorithm is more simple and effective method to determine 2-D PSF of the x-ray imaging system than traditional methods. Image based scatter correction scheme to reduce the scatter effects was proposed. This algorithm corrects scatter on projection images based on convolution, scatter fraction, and angular interpolation. The scatter signal was estimated by convolving a projection image with scatter point spread function (SPSF) followed by multiplication with scatter fraction. Scatter fraction was estimated using collimator which is similar to SPECS method. This method does not require extra x-ray dose and any additional phantom. Maximum estimated error for interpolation was less than 7

  17. Kilovoltage Rotational External Beam Radiotherapy on a Breast Computed Tomography Platform: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Prionas, Nicolas D.; McKenney, Sarah E. [Department of Radiology, University of California, Davis, Medical Center, Sacramento, California (United States); Stern, Robin L. [Department of Radiation Oncology, University of California, Davis, Medical Center, Sacramento, California (United States); Boone, John M., E-mail: jmboone@ucdavis.edu [Department of Radiology, University of California, Davis, Medical Center, Sacramento, California (United States)

    2012-10-01

    Purpose: To demonstrate the feasibility of a dedicated breast computed tomography (bCT) platform to deliver rotational kilovoltage (kV) external beam radiotherapy (RT) for partial breast irradiation, whole breast irradiation, and dose painting. Methods and Materials: Rotational kV-external beam RT using the geometry of a prototype bCT platform was evaluated using a Monte Carlo simulator. A point source emitting 178 keV photons (approximating a 320-kVp spectrum with 4-mm copper filtration) was rotated around a 14-cm voxelized polyethylene disk (0.1 cm tall) or cylinder (9 cm tall) to simulate primary and primary plus scattered photon interactions, respectively. Simulations were also performed using voxelized bCT patient images. Beam collimation was varied in the x-y plane (1-14 cm) and in the z-direction (0.1-10 cm). Dose painting for multiple foci, line, and ring distributions was demonstrated using multiple rotations with varying beam collimation. Simulations using the scanner's native hardware (120 kVp filtered by 0.2-mm copper) were validated experimentally. Results: As the x-y collimator was narrowed, the two-dimensional dose profiles shifted from a cupped profile with a high edge dose to an increasingly peaked central dose distribution with a sharp dose falloff. Using a 1-cm beam, the cylinder edge dose was <7% of the dose deposition at the cylinder center. Simulations using 120-kVp X-rays showed distributions similar to the experimental measurements. A homogeneous dose distribution (<2.5% dose fluctuation) with a 20% decrease in dose deposition at the cylinder edge (i.e., skin sparing) was demonstrated by weighted summation of four dose profiles using different collimation widths. Simulations using patient bCT images demonstrated the potential for treatment planning and image-guided RT. Conclusions: Rotational kV-external beam RT for partial breast irradiation, dose painting, and whole breast irradiation with skin sparing is feasible on a bCT platform

  18. Cone-beam breast computed tomography with a displaced flat panel detector array

    Energy Technology Data Exchange (ETDEWEB)

    Mettivier, Giovanni; Russo, Paolo; Lanconelli, Nico; Meo, Sergio Lo [Universita di Napoli Federico II, Dipartimento di Scienze Fisiche, and INFN, Sezione di Napoli, I-80126 Napoli (Italy); Alma Mater Studiorum-Universita di Bologna, Dipartimento di Fisica, and INFN, Sezione di Bologna, I-40127 Bologna (Italy)

    2012-05-15

    Purpose: In cone-beam computed tomography (CBCT), and in particular in cone-beam breast computed tomography (CBBCT), an important issue is the reduction of the image artifacts produced by photon scatter and the reduction of patient dose. In this work, the authors propose to apply the detector displacement technique (also known as asymmetric detector or ''extended view'' geometry) to approach this goal. Potentially, this type of geometry, and the accompanying use of a beam collimator to mask the unirradiated half-object in each projection, permits some reduction of radiation dose with respect to conventional CBBCT and a sizeable reduction of the overall amount of scatter in the object, for a fixed contrast-to-noise ratio (CNR). Methods: The authors consider a scan configuration in which the projection data are acquired from an asymmetrically positioned detector that covers only one half of the scan field of view. Monte Carlo simulations and measurements, with their CBBCT laboratory scanner, were performed using PMMA phantoms of cylindrical (70-mm diameter) and hemiellipsoidal (140-mm diameter) shape simulating the average pendant breast, at 80 kVp. Image quality was evaluated in terms of contrast, noise, CNR, contrast-to-noise ratio per unit of dose (CNRD), and spatial resolution as width of line spread function for high contrast details. Results: Reconstructed images with the asymmetric detector technique deviate less than 1% from reconstruction with a conventional symmetric detector (detector view) and indicate a reduction of the cupping artifact in CT slices. The maximum scatter-to-primary ratio at the center of the phantom decreases by about 50% for both small and large diameter phantoms (e.g., from 0.75 in detector view to 0.40 in extended view geometry at the central axis of the 140-mm diameter PMMA phantom). Less cupping produces an increase of the CT number accuracy and an improved image detail contrast, but the associated increase of

  19. Scatter correction for cone-beam computed tomography using self-adaptive scatter kernel superposition

    International Nuclear Information System (INIS)

    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. (authors)

  20. 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

  1. 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.

  2. A comparative study for image quality and radiation dose of a cone beam computed tomography scanner and a multislice computed tomography scanner for paranasal sinus imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cock, Jens de; Canning, John [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Zanca, Federica; Hermans, Robert [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); KU Leuven, Imaging and Pathology Department, Leuven (Belgium); Pauwels, Ruben [KU Leuven, Imaging and Pathology Department, Leuven (Belgium)

    2015-07-15

    To evaluate image quality and radiation dose of a state of the art cone beam computed tomography (CBCT) system and a multislice computed tomography (MSCT) system in patients with sinonasal poliposis. In this retrospective study two radiologists evaluated 57 patients with sinonasal poliposis who underwent a CBCT or MSCT sinus examination, along with a control group of 90 patients with normal radiological findings. Tissue doses were measured using a phantom model with thermoluminescent dosimeters (TLD). Overall image quality in CBCT was scored significantly higher than in MSCT in patients with normal radiologic findings (p-value: 0.00001). In patients with sinonasal poliposis, MSCT scored significantly higher than CBCT (p-value: 0.00001). The average effective dose for MSCT was 42 % higher compared to CBCT (108 μSv vs 63 μSv). CBCT and MSCT are both suited for the evaluation of sinonasal poliposis. In patients with sinonasal poliposis, clinically important structures of the paranasal sinuses can be better delineated with MSCT, whereas in patients without sinonasal poliposis, CBCT turns out to define the important structures of the sinonasal region better. However, given the lower radiation dose, CBCT can be considered for the evaluation of the sinonasal structures in patients with sinonasal poliposis. (orig.)

  3. 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. PMID:27563194

  4. 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.

  5. Volumetric analysis of the mandibular condyle using cone beam computed tomography

    International Nuclear Information System (INIS)

    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.

  6. 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.

  7. Unusual bilateral dentigerous cysts in a nonsyndromic patient assessed by cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Thais Sumie Imada

    2014-01-01

    Full Text Available In the absence of syndromes, bilateral dentigerous cysts (DC located on the jaws are unusual. In English based language literature review, we only found eight reports of nonsyndromic bilateral dentigerous cyst associated with mandibular third molars. Therefore, we report the unusual occurrence of sizable nonsyndromic bilateral DC associated with mandibular impacted third molars in a 42-year-old Caucasian woman. The lesions were assessed by cone beam computed tomography (CBCT the right lesion showed approximately 23.64 mm and the left one, 16.57 mm diameter, both located intimately next to the mandibular canal. Bilateral surgical enucleation, related teeth excision of both third molars and plate for fixation placement on the right and bigger lesion, under general anesthesia was the final treatment choice. Clinical, radiographic and histopathological features confirmed diagnose of bilateral dentigerous cyst. Now-a-days, the patient is on 18 months radiograph follow-up with favorable osseous formation with no evidence of recurrence of the cysts.

  8. Effect of root canal filling materials on dimensions of cone-beam computed tomography images

    Directory of Open Access Journals (Sweden)

    Daniel Almeida Decurcio

    2012-04-01

    Full Text Available OBJECTIVE:To evaluate the discrepancy of root canal filling (RCF measurements obtained from original root specimens and cone-beam computed tomography (CBCT images. MATERIAL AND METHODS: Seventy-two human maxillary anterior teeth were prepared up to an ISO #50 K-File 1 mm short of the apical foramen. Thus, the teeth were randomly divided into 8 groups, according to the root canal filling material: Sealapex ®, Sealapex®+gutta-percha points, Sealer 26®, Sealer 26®+gutta-percha points, AH PlusTM, AH PlusTM+gutta-percha points, Grossman Sealer, and Grossman Sealer+gutta-percha points. After root canal preparation and RCF, CBCT scans were acquired and the specimens were sectioned in axial, sagittal and coronal planes. The RCF measurements were obtained in different planes and thicknesses to determine the discrepancy between the original root specimens (using a digital caliper and the CBCT images (using the scanner’s proprietary software. One-way analysis of variance and Tukey tests were used for statistical analyses. The significance level was set at α=5%. RESULTS: Measurements of the different endodontic filling materials were 9% to 100% greater on the CBCT images than on the original root specimens. Greater RCF dimensions were found when only sealers were used, with statistically significant difference among the groups. CONCLUSIONS: RCF dimensions were greater on CBCT images than on the original root specimens, especially when only sealer was used.

  9. 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.)

  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. PMID:27563194

  11. Dosimetric evaluation of dental implant planning examinations with cone-beam computed tomography

    International Nuclear Information System (INIS)

    The aim of this work was to perform a dosimetric evaluation of two cone-beam computed tomography scanners. The study was performed with two scanners: i-CAT classic and PreXion 3D. Air kerma-area product (PKA) was measured for all full-arch dental implant planning protocols. Surface air kerma was also estimated at the region of the eyes, salivary glands and thyroid using thermoluminescence dosemeters positioned on an anthropomorphic phantom. The PKA values for the i-CAT classic ranged from 24 to 180 μGym2 and, for the PreXion, from 70 to 138 μGym2. The large variation of these values was mainly caused by acquisition time and field of views. The surface air kerma values were from 0.08 to 3.39 mGy at the eyes, 0.50 to 3.96 mGy at the parotids, 0.11 to 2.95 mGy at the submandibular glands and 0.05 to 1.32 mGy at the thyroid. These values are comparable with those found in the literature. (authors)

  12. 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.

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

    Science.gov (United States)

    Zahedpasha, Samir; Rathore, Sonali A.; Mupparapu, Mel

    2016-01-01

    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. PMID:27358822

  14. 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.

  15. 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.

  16. Image characteristics of cone beam computed tomography using a CT performance phantom

    International Nuclear Information System (INIS)

    To evaluate the characteristics of (widely used) cone beam computed tomography (CBCT) images. Images were obtained with CT performance phantoms (The American Association of Physicists in Medicine; AAPM). CT phantom as the destination by using PSR 9000N TM dental CT system (Asahi Roentgen Ind. Co., Ltd., Japan) and i-CAT CBCT (Imaging Science International Inc., USA) that have different kinds of detectors and field of view, and compared these images with the CT number for linear attenuation, contrast resolution, and spatial resolution. CT number of both PSR 9000N TM dental CT system and i-CAT CBCT did not conform to the base value of CT performance phantom. The contrast of i-CAT CBCT is higher than that of PSR 9000N TM dental CT system. Both contrasts were increased according to thickness of cross section. Spatial resolution and shapes of reappearance was possible up to 0.6 mm in PSR 9000N TM dental CT system and up to 1.0 mm in i-CAT CBCT. Low contrast resolution in region of low contrast sensitivity revealed low level at PSR 9000N TM dental CT system and i-CAT CBCT. CBCT images revealed higher spatial resolution, however, contrast resolution in region of low contrast sensitivity was the inferiority of image characteristics

  17. 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)

  18. 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  DP algorithm performed similarly (1.5+/- 0.8 mm versus 1.6+/- 0.9 mm, p  =  0.48) compared to the manual setup matching the fiducial markers in the 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.

  19. Three-dimensional maxillary and mandibular regional superimposition using cone beam computed tomography: a validation study.

    Science.gov (United States)

    Koerich, L; Burns, D; Weissheimer, A; Claus, J D P

    2016-05-01

    This study aimed to validate a novel method for fast regional superimposition of cone beam computed tomography (CBCT) scans. The method can be used with smaller field of view scans, thereby allowing for a lower radiation dose. This retrospective study used two dry skulls and secondary data from 15 patients who had more than one scan taken using the same machine. Two observers tested two types of regional voxel-based superimposition: maxillary and mandibular. The registration took 10-15s. Three-dimensional surface models of the maxillas and mandibles were generated via standardized threshold segmentation, and the accuracy and reproducibility of the superimpositions were assessed using the iterative closest point technique to measure the root mean square (RMS) distance between the images. Five areas were measured and a RMS≤0.25 was considered successful. Descriptive statistics and the intra-class correlation coefficient (ICC) were used to compare the intra-observer measurement reproducibility. The ICC was ≥0.980 for all of the variables and the highest RMS found was 0.241. The inter-observer reproducibility was assessed case by case and was perfect (RMS 0) for 68% (23 out of 34) of the superimpositions done and not clinically significant (RMS≤0.25) for the other 32%. The method is fast, accurate, and reproducible and is an alternative to cranial base superimposition. PMID:26794399

  20. Assessment of Mandibular Distraction Regenerate Using Ultrasonography and Cone Beam Computed Tomography: A Clinical Study.

    Science.gov (United States)

    Dabas, Jitender; Mohanty, Sujata; Chaudhary, Zainab; Rani, Amita

    2016-03-01

    Distraction osteogenesis (DO) is becoming a popular method of reconstruction for maxillofacial bony deformities or defects secondary to trauma or surgical tumor ablation. However, the technique is very sensitive in terms of the rate and rhythm of distraction. Because of this, there is a need for monitoring of the distraction regenerate during the distraction as well as the consolidation period. The present study was conducted to assess the regenerate using two imaging modalities, namely, ultrasonography (USG) and cone beam computed tomography (CBCT) to determine their relative efficacies and to weigh their clinical usefulness in assessment of DO regenerate. The study was conducted on 12 patients (18 sites) who underwent mandibular distraction for correction of facial deformities. The results showed that overall USG correlated better with the condition of regenerate (r = 0.606) as compared with CBCT (r = 0.476). However, USG was less effective as compared with CBCT in assessing the regenerate once corticomedullary differentiation occurred in the bone. PMID:26889351

  1. The evaluation of palatal bone thickness for implant insertion with cone beam computed tomography.

    Science.gov (United States)

    Sumer, A P; Caliskan, A; Uzun, C; Karoz, T B; Sumer, M; Cankaya, S

    2016-02-01

    The palate is an alternative anchoring site for orthodontic implants and screws. The use of osseointegrated implants in the intermaxillary suture has recently been described as a fast, effective, and low-cost technique for patients with atrophy of the maxillae. The aim of this study was to use cone beam computed tomography (CBCT) to evaluate the thickness of the bone surrounding the intermaxillary suture in relation to the insertion of osseointegrated implants. CBCT images of 144 patients (72 males, 72 females) aged 35-86 years were evaluated. The vertical bone height of the intermaxillary suture was measured using coronal and sagittal Images 5, 10, 15, 20, and 25 mm posterior to the incisive foramen. The mean bone thicknesses from the anterior to the posterior region were 5.59, 4.38, 3.91, 3.95, and 3.94 mm, respectively. Bone thickness was significantly different among the five anteroposterior areas of the suture, but there were no significant differences between males and females, or among age groups. The highest part of the intermaxillary suture was in the anterior region. Three-dimensional imaging is recommended to accurately identify palate bone thickness for implant placement. PMID:26458537

  2. Osteoporosis prediction from the mandible using cone-beam computed tomography

    International Nuclear Information System (INIS)

    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.

  3. 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.

  4. Does hyrax expansion therapy affect maxillary sinus volume? A cone-beam computed tomography report

    International Nuclear Information System (INIS)

    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.

  5. 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.

  6. Assessment of the relationship between the maxillary molars and adjacent structures using cone beam computed tomography

    International Nuclear Information System (INIS)

    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.

  7. Detectability of hepatic tumors during 3D post-processed ultrafast cone-beam computed tomography

    International Nuclear Information System (INIS)

    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  <  0.05) diagnostic ability for hepatic tumors compared to UCBCT or PBV image data. The detectability of small hepatic tumors (<5 mm) was significantly reduced (all P  <  0.05) using UCBCT cross-sectional images compared to MRI or fused image data; however, PBV improved tumor detectability using a 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. (paper)

  8. Dosimetry of cone beam computed tomography scanning for diagnosis and planning in implant dentistry

    International Nuclear Information System (INIS)

    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)

  9. Mandibular incisive canal in Han Chinese using cone beam computed tomography.

    Science.gov (United States)

    Kong, N; Hui, M; Miao, F; Yuan, H; Du, Y; Chen, N

    2016-09-01

    The aim of this study was to provide reference information for implantology and chin bone harvesting in people of Han Chinese ethnicity by studying the mandibular incisive canal (MIC) using cone beam computed tomography (CBCT). Fifty subjects were included in the study. CBCT scans were obtained for all subjects, and 22 also underwent panoramic radiography to evaluate the visibility of the MIC. The CBCT data of the 50 subjects were reconstructed to measure MIC diameter, length, and location within the mandible. A MIC was identified in 38.6% of panoramic radiographs, with good clarity in 13.6%, while a MIC was identified in 100% of CBCT images, with good clarity in 63.6%. The diameter of the MIC decreased from origin to end. The left and right average MIC lengths were 17.84mm and 17.73mm, respectively. The MIC was close to the buccal cortical border and lower margin of the mandible. In conclusion, the MIC is an anatomical structure in the mandible that can be identified reliably with CBCT. On insertion, implants should be inclined slightly towards the lingual aspect of the anterior mandible to protect the MIC. The chin bone harvesting depth should be limited to 4mm; the harvesting site can be adjusted to the region above or below the MIC. PMID:27184354

  10. Selective doxorubicin drug eluting beads chemoembolization of hypovascular hepatocellular carcinoma using cone beam computed tomography

    Directory of Open Access Journals (Sweden)

    Naveen Kalra

    2012-01-01

    Full Text Available Hepatocellular carcinoma (HCC of the liver is the third most common cause of cancer-related deaths in the world. Only one-third of patients with HCC are suitable candidates for hepatic resection. Transarterial chemoembolization (TACE is performed in unresectable HCC. Drug-eluting beads (DEB TACE is a modification of TACE, in which doxorubicin beads are used as embolizing material.These beads deliver the drug and embolize the vessels; however, it carries the risk of non-target embolization and it is difficult in cases with absent arterial blush on digital subtraction angiography (DSA. This is resolved using C-arm cone-beam computed tomography in the DSA suite. It identifies the tumor-feeding vessels, their area of supply, and differentiates between tumor and normal liver parenchyma. In addition, it is very useful in the embolization of hypovascular HCC. It helps and guides the radiologist in performing TACE effectively and also prevents non-target embolization of normal liver parenchyma.

  11. Selective doxorubicin drug eluting beads chemoembolization of hypovascular hepatocellular carcinoma using cone beam computed tomography.

    Science.gov (United States)

    Kalra, Naveen; Mahajan, Divyesh; Chawla, Yogesh; Khandelwal, N

    2012-10-01

    Hepatocellular carcinoma (HCC) of the liver is the third most common cause of cancer-related deaths in the world. Only one-third of patients with HCC are suitable candidates for hepatic resection. Transarterial chemoembolization (TACE) is performed in unresectable HCC. Drug-eluting beads (DEB) TACE is a modification of TACE, in which doxorubicin beads are used as embolizing material. These beads deliver the drug and embolize the vessels; however, it carries the risk of non-target embolization and it is difficult in cases with absent arterial blush on digital subtraction angiography (DSA). This is resolved using C-arm cone-beam computed tomography in the DSA suite. It identifies the tumor-feeding vessels, their area of supply, and differentiates between tumor and normal liver parenchyma. In addition, it is very useful in the embolization of hypovascular HCC. It helps and guides the radiologist in performing TACE effectively and also prevents non-target embolization of normal liver parenchyma. PMID:23833414

  12. The relationship between dental implant stability and trabecular bone structure using cone-beam computed tomography

    Science.gov (United States)

    2016-01-01

    Purpose The objective of this study was to investigate the relationships between primary implant stability as measured by impact response frequency and the structural parameters of trabecular bone using cone-beam computed tomography(CBCT), excluding the effect of cortical bone thickness. Methods We measured the impact response of a dental implant placed into swine bone specimens composed of only trabecular bone without the cortical bone layer using an inductive sensor. The peak frequency of the impact response spectrum was determined as an implant stability criterion (SPF). The 3D microstructural parameters were calculated from CT images of the bone specimens obtained using both micro-CT and CBCT. Results SPF had significant positive correlations with trabecular bone structural parameters (BV/TV, BV, BS, BSD, Tb.Th, Tb.N, FD, and BS/BV) (P<0.01) while SPF demonstrated significant negative correlations with other microstructural parameters (Tb.Sp, Tb.Pf, and SMI) using micro-CT and CBCT (P<0.01). Conclusions There was an increase in implant stability prediction by combining BV/TV and SMI in the stepwise forward regression analysis. Bone with high volume density and low surface density shows high implant stability. Well-connected thick bone with small marrow spaces also shows high implant stability. The combination of bone density and architectural parameters measured using CBCT can predict the implant stability more accurately than the density alone in clinical diagnoses. PMID:27127692

  13. 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. PMID:26194774

  14. 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.

  15. 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.

  16. 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)

  17. 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.

  18. A cone beam computed tomography inspection method for fuel rod cladding tubes

    Science.gov (United States)

    Fu, Jian; Tan, Renbo; Wang, Qianli; Deng, Jingshan; Liu, Ming

    2012-10-01

    Fuel rods in nuclear power plants consist of UO2 pellets enclosed in Zirconium alloy (Zircaloy) cladding tube, which is composed of a body and a plug. The body is manufactured separately from the plug and, before its use, the plug is welded with the body. It is vitally important for the welding zone to remain free from defects after the fuel pellets are loaded into the cladding tube to prevent the radioactive fission products from leaking. X-ray computed tomography (CT) is in principle a feasible inspection method for the welding zone, but it faces several challenges due to the high attenuation of Zircaloy. In this paper, a cone beam CT method is proposed to address these issues and perform the welding flaw inspection. A Zircaloy compensator is adopted to narrow the signal range, a structure-based background removal technique to reveal the defects, a linear extension technique to determine the reference X-ray intensity signal and FDK algorithm to reconstruct the slice images. A prototype system, based on X-ray tube source and flat panel detector, has been developed and the experiments in this system have demonstrated that the welding void and the incomplete joint penetrations could be detected by this method. This approach may find applications in the quality control of nuclear fuel rods.

  19. Accuracy of digital peripical radiography and cone-beam computed tomography in detecting external root resorption

    International Nuclear Information System (INIS)

    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

  20. A cone beam computed tomography inspection method for fuel rod cladding tubes

    International Nuclear Information System (INIS)

    Fuel rods in nuclear power plants consist of UO2 pellets enclosed in Zirconium alloy (Zircaloy) cladding tube, which is composed of a body and a plug. The body is manufactured separately from the plug and, before its use, the plug is welded with the body. It is vitally important for the welding zone to remain free from defects after the fuel pellets are loaded into the cladding tube to prevent the radioactive fission products from leaking. X-ray computed tomography (CT) is in principle a feasible inspection method for the welding zone, but it faces several challenges due to the high attenuation of Zircaloy. In this paper, a cone beam CT method is proposed to address these issues and perform the welding flaw inspection. A Zircaloy compensator is adopted to narrow the signal range, a structure-based background removal technique to reveal the defects, a linear extension technique to determine the reference X-ray intensity signal and FDK algorithm to reconstruct the slice images. A prototype system, based on X-ray tube source and flat panel detector, has been developed and the experiments in this system have demonstrated that the welding void and the incomplete joint penetrations could be detected by this method. This approach may find applications in the quality control of nuclear fuel rods.

  1. Metal artifact reduction in cone beam computed tomography using forward projected reconstruction information

    International Nuclear Information System (INIS)

    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.)

  2. Electron-beam computed tomography findings of left atrial appendage in patients with cardiogenic cerebral embolism

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Makiko; Takahashi, Satoshi; Yonezawa, Hisashi [Iwate Medical Univ., Morioka (Japan). School of Medicine

    2002-04-01

    We studied electron-beam computed tomography (EBCT) findings in the left atrial appendage of 72 patients with cerebral embolism [27 in the acute phase (<48 hours) and 45 in the chronic phase], 9 cases with nonvalvular atrial fibrillation (NVAF) but without stroke, and 13 controls. EBCT was performed in the early (during injection of contrast medium), late-1 (5 min after injection), and-2 (10 min after injection) phases. In the acute phase patients, 41% showed filling defect (FD) in the early phase alone (FDE), 15% showed FD until late phase-1 (FDL-1), and 15% showed FD until late phase-2 (FDL-2). The chronic phase patients showed FDE in 33% of cases, FDL-1 in 8% and FDL-2 11%. Only FDE was observed in 44% in NVAF cases without stroke. No FDs were observed in controls. Flow velocity in the appendage measured by transesophageal echocardiography was 23{+-}10 cm/sec in 21 FDE cases, 14{+-}3 cm/sec in 3 FDL-1 cases, 29{+-}23 cm/sec in 4 FDL-2 cases, significantly lower in comparison with 58{+-}25 cm/s in the 23 cases with no FD. FDL-1 and -2 suggested severe stasis or presence of thrombus in the appendage, which indicated high risk of embolism slower the movement of MES through the sample volume. (author)

  3. Accuracy and reliability of stitched cone-beam computed tomography images

    International Nuclear Information System (INIS)

    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.

  4. Cone Beam Computed Tomography Image Guidance System for a Dedicated Intracranial Radiosurgery Treatment Unit

    International Nuclear Information System (INIS)

    Purpose: Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. Methods and Materials: A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210° of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Results: Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited <0.2 mm peak-to-peak variation. With a 0.5-mm voxel pitch, the maximum targeting error was 0.4 mm. Images of 2 patients were analyzed offline and submillimeter agreement was confirmed with conventional frame. Conclusions: A cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of producing

  5. Cone Beam Computed Tomography Image Guidance System for a Dedicated Intracranial Radiosurgery Treatment Unit

    Energy Technology Data Exchange (ETDEWEB)

    Ruschin, Mark, E-mail: Mark.Ruschin@sunnybrook.ca [Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Komljenovic, Philip T.; Ansell, Steve [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Menard, Cynthia [Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Bootsma, Gregory [Department of Medical Biophysics, University of Toronto, Ontario (Canada); Cho, Young-Bin; Chung, Caroline; Jaffray, David [Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada)

    2013-01-01

    Purpose: Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. Methods and Materials: A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210 Degree-Sign of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Results: Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited <0.2 mm peak-to-peak variation. With a 0.5-mm voxel pitch, the maximum targeting error was 0.4 mm. Images of 2 patients were analyzed offline and submillimeter agreement was confirmed with conventional frame. Conclusions: A cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of

  6. Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation

    International Nuclear Information System (INIS)

    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

  7. Radiation Dose From Kilovoltage Cone Beam Computed Tomography in an Image-Guided Radiotherapy Procedure

    International Nuclear Information System (INIS)

    Purpose: Image-guided radiation therapy has emerged as the new paradigm in radiotherapy. This work is to provide detailed information concerning the additional imaging doses to patients' radiosensitive organs from a kilovoltage cone beam computed tomography (kV CBCT) scan procedure. Methods and Materials: The Vanderbilt-Monte-Carlo-Beam-Calibration (VMCBC; Vanderbilt University, Nashville, TN) algorithm was used to calculate radiation dose to organs resulting from a kV CBCT imaging guidance procedure. Eight patients, including 3 pediatric and 5 adult patients, were investigated. The CBCT scans in both full- and half-fan modes were studied. Results: For a head-and-neck scan in half-fan mode, dose-volume histogram analyses show mean doses of 7 and 8 cGy to the eyes, 5 and 6 cGy to the spinal cord, 5 and 6 cGy to the brain, and 18 and 23 cGy to the cervical vertebrae for an adult and a 29-month-old child, respectively. The dose from a scan in full-fan mode is 10-20% lower than that in half-fan mode. For an abdominal scan, mean doses are 3 and 7 cGy to prostate and 7 and 17 cGy to femoral heads for a large adult patient and a 31-month-old pediatric patient, respectively. Conclusions: Doses to radiosensitive organs can total 300 cGy accrued over an entire treatment course if kV CBCT scans are acquired daily. These findings provide needed data for clinicians to make informed decisions concerning additional imaging doses. The dose to bone is two to four times greater than dose to soft tissue for kV x-rays, which should be considered, especially for pediatric patients

  8. 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

  9. Accuracy and feasibility of cone-beam computed tomography for stereotactic radiosurgery setup

    International Nuclear Information System (INIS)

    Image fusion, target localization, and setup accuracy of cone-beam computed tomography (CBCT) for stereotactic radiosurgery (SRS) were investigated in this study. A Rando head phantom rigidly attached to a stereotactic Brown-Roberts-Wells (BRW) frame was utilized to study the geometric accuracy of CBCT. Measurements of distances and angular separations between selected pairs of multiple radio-opaque targets embedded in the head phantom from a conventional simulation CT provided comparative data for geometric accuracy analysis. Localization accuracy of the CBCT scan was investigated from an analysis of BRW localization of four cylindrical objects (9 mm in diameter and 25 mm in length) independently computed from CBCT and conventional CT scans. Image fusion accuracy was quantitatively evaluated from BRW localization of multiple simulated targets from the CBCT and conventional CT scan. Finally, a CBCT setup procedure for stereotactic radiosurgery treatments was proposed and its accuracy was assessed using orthogonal target verification imaging. Our study showed that CBCT did not present any significant geometric distortions. Stereotactic coordinates of the four cylindrical objects as determined from the CBCT differed from those determined from the conventional CT on average by 0.30 mm with a standard deviation (SD) of 0.09 mm. The mean image registration accuracy of CBCT with conventional CT was 0.28 mm (SD=0.10 mm). Setup uncertainty of our proposed CBCT setup procedure was on the same order as the conventional framed-based stereotactic systems reported in the literature (mean=1.34 mm, SD=0.33 mm). In conclusion, CBCT can be used to guide SRS treatment setup with accuracy comparable to the currently used frame-based stereotactic radiosurgery systems provided that intra-treatment patient motion is prevented

  10. Cone-beam Computed Tomography-guided Stereotactic Liver Punctures: A Phantom Study

    Energy Technology Data Exchange (ETDEWEB)

    Toporek, Grzegorz, E-mail: grzegorz.toporek@artorg.unibe.ch; Wallach, Daphne, E-mail: daphne.wallach@artorg.unibe.ch; Weber, Stefan [ARTORG Center for Biomedical Engineering Research, University of Bern (Switzerland); Bale, Reto; Widmann, Gerlig [Innsbruck Medical University, Section of Microinvasive Therapy, Department of Radiology (Austria)

    2013-12-15

    Purpose: Images from computed tomography (CT), combined with navigation systems, improve the outcomes of local thermal therapies that are dependent on accurate probe placement. Although the usage of CT is desired, its availability for time-consuming radiological interventions is limited. Alternatively, three-dimensional images from C-arm cone-beam CT (CBCT) can be used. The goal of this study was to evaluate the accuracy of navigated CBCT-guided needle punctures, controlled with CT scans. Methods: Five series of five navigated punctures were performed on a nonrigid phantom using a liver specific navigation system and CBCT volumetric dataset for planning and navigation. To mimic targets, five titanium screws were fixed to the phantom. Target positioning accuracy (TPE{sub CBCT}) was computed from control CT scans and divided into lateral and longitudinal components. Additionally, CBCT-CT guidance accuracy was deducted by performing CBCT-to-CT image coregistration and measuring TPE{sub CBCT-CT} from fused datasets. Image coregistration was evaluated using fiducial registration error (FRE{sub CBCT-CT}) and target registration error (TRE{sub CBCT-CT}). Results: Positioning accuracies in lateral directions pertaining to CBCT (TPE{sub CBCT} = 2.1 {+-} 1.0 mm) were found to be better to those achieved from previous study using CT (TPE{sub CT} = 2.3 {+-} 1.3 mm). Image coregistration error was 0.3 {+-} 0.1 mm, resulting in an average TRE of 2.1 {+-} 0.7 mm (N = 5 targets) and average Euclidean TPE{sub CBCT-CT} of 3.1 {+-} 1.3 mm. Conclusions: Stereotactic needle punctures might be planned and performed on volumetric CBCT images and controlled with multidetector CT with positioning accuracy higher or similar to those performed using CT scanners.

  11. Computed tomography from photon statistics to modern cone-beam CT

    CERN Document Server

    Buzug, T M

    2008-01-01

    Tis book provides an overview of X-ray technology, the historic developmental milestones of modern CT systems, and gives a comprehensive insight into the main reconstruction methods used in computed tomography. Te basis of reconstr- tion is, undoubtedly, mathematics. However, the beauty of computed tomography cannot be understood without a detailed knowledge of X-ray generation, photon- matter interaction, X-ray detection, photon statistics, as well as fundamental signal processing concepts and dedicated measurement systems. Terefore, the reader will ?nd a number of references to these basic d

  12. Capabilities of Cone-Beam Computed Tomography in the Assessment of the Structure of Wrist and Hand Bones

    Directory of Open Access Journals (Sweden)

    А.Yu. Vasiliev, PhD, MD

    2013-06-01

    Full Text Available An analysis of the capabilities of cone-beam computed tomography (CBCT in the assessment of the form and structure of wrist and hand bones was the aim of the research. Cone-beam CT of wrist and hand was conducted in a group of voluntary patients, which included 40 members aged 22- 68 years. Magnetic resonance imaging (МRI was carried out in 80.0% (n = 32 of cases, multislice computed tomography (MSCT in 40.0% (n=16 of cases. In 62.5 % (n=25 of cases, digital microfocus radiography on X-ray unit Pardus (Russia and standard radiography of wrist and hand were conducted. According to the results of the research, CBCT shows a high efficiency in detection of form, measurements and structural changes of bones of the anatomic region.

  13. Development of CCD-based optical computed tomography and comparison with single-beam optical CT scanner

    International Nuclear Information System (INIS)

    This study reports on the development of CCD-based optical computed tomography (CT) CT-s2. A commercially available 10× fast optical computed tomography scanner (OCTOPUSTM-10X, MGS Research, Inc., Madison, CT, USA) was used for comparison. NIPAM polymer gel dosimeter was used to validate the performance of CT-s2. The gamma pass rate can reach 96.00% when using a 3% dose difference and 3 mm dose-to-agreement criteria. The results of CT-s2 are as good as those of the single-beam optical-CT scanner, but the scanning time of CT-s2 is only one-tenth of that of the single-beam optical-CT scanner

  14. Crown and root lengths of incisors, canines, and premolars measured by cone-beam computed tomography in patients with malocclusions

    OpenAIRE

    Kim, Seon-Young; Lim, Sung-Hoon; Gang, Sung-Nam; Kim, Hee-Jin

    2013-01-01

    Objective The purposes of this study were to determine the accuracy of crown and root length measurements of premolars using cone-beam computed tomography (CBCT) and to generate reference CBCT-based data on incisor, canine, and premolar lengths in patients with malocclusions. Methods Imaging was performed using a CBCT scanner with a 0.292-mm voxel size and 12-bit grayscale. The CBCT-based length measurements were compared with direct measurements of 94 subsequently extracted premolars without...

  15. A local shift-variant Fourier model and experimental validation of circular cone-beam computed tomography artifacts

    OpenAIRE

    Bartolac, Steven; Clackdoyle, Rolf; Noo, Frederic; Siewerdsen, Jeff; Moseley, Douglas; Jaffray, David

    2009-01-01

    Large field of view cone-beam computed tomography (CBCT) is being achieved using circular source and detector trajectories. These circular trajectories are known to collect insufficient data for accurate image reconstruction. Although various descriptions of the missing information exist, the manifestation of this lack of data in reconstructed images is generally nonintuitive. One model predicts that the missing information corresponds to a shift-variant cone of missing frequency components. ...

  16. Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

    OpenAIRE

    Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin; Hwang, Hyeon-Shik

    2016-01-01

    Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions wer...

  17. Cone beam computed tomography findings of ectopic mandibular third molar in the mandibular condyle: report of a case

    OpenAIRE

    Kim, Jin-Soo

    2011-01-01

    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.

  18. 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.

  19. Assessment of the Airway Characteristics in Children with Cleft Lip and Palate using Cone Beam Computed Tomography

    Science.gov (United States)

    Marwah, Nikhil

    2016-01-01

    ABSTRACT Objective: The aim of our study is to use cone beam computed tomography (CBCT) to assess the dimensional changes in the nasopharyngeal soft-tissue characteristics in children of Indian origin with repaired cleft lip and palate (CLP) and to compare the results with patients with ideal occlusion. Materials and methods: A sample of 20 children (10 girls, 10 boys) with repaired CLP was selected. Cone beam computed tomography scans were taken to measure the nasopharyngeal airway changes in terms of linear measurements and sagittal cross-sectional areas. Error analysis was performed to prevent systematic or random errors. Independent means t-tests and Pearson correlation analysis were used to evaluate sex differences and the correlations among the variables. Results: Nasopharyngeal soft-tissue characteristics were different in the control and the study groups. Subjects with repaired CLP had lesser lower aerial width, lower adenoidal width and lower airway width. The upper airway width was also significantly lesser. The retropalatal and the total airway area were significantly greater in the control group. Conclusion: The narrow pharyngeal airway in patients with CLP might result in functional impairment of breathing in patients. Further investigations are necessary to clarify the relationship between pharyngeal structure and airway function in patients with CLP. How to cite this article: Agarwal A, Marwah N. Assessment of the Airway Characteristics in Children with Cleft Lip and Palate using Cone Beam Computed Tomography. Int J Clin Pediatr Dent 2016;9(1):5-9. PMID:27274147

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head What is CT Scanning of the ... Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  1. Comparison between cone beam computed tomography and magnetic resonance imaging of the temporomandibular joint

    International Nuclear Information System (INIS)

    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.

  2. 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.

  3. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT)

    International Nuclear Information System (INIS)

    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.

  4. Evaluation of condyle defects using different reconstruction protocols of cone-beam computed tomography

    International Nuclear Information System (INIS)

    This study was conducted to investigate how well cone-beam computed tomography (CBCT) can detect simulated cavitary defects in condyles, and to test the influence of the reconstruction protocols. Defects were created with spherical diamond burs (numbers 1013, 1016, 3017) in superior and / or posterior surfaces of twenty condyles. The condyles were scanned, and cross-sectional reconstructions were performed with nine different protocols, based on slice thickness (0.2, 0.6, 1.0 mm) and on the filters (original image, Sharpen Mild, S9) used. Two observers evaluated the defects, determining their presence and location. Statistical analysis was carried out using simple Kappa coefficient and McNemar’s test to check inter- and intra-rater reliability. The chi-square test was used to compare the rater accuracy. Analysis of variance (Tukey's test) assessed the effect of the protocols used. Kappa values for inter- and intra-rater reliability demonstrate almost perfect agreement. The proportion of correct answers was significantly higher than that of errors for cavitary defects on both condyle surfaces (p < 0.01). Only in identifying the defects located on the posterior surface was it possible to observe the influence of the 1.0 mm protocol thickness and no filter, which showed a significantly lower value. Based on the results of the current study, the technique used was valid for identifying the existence of cavities in the condyle surface. However, the protocol of a 1.0 mm-thick slice and no filter proved to be the worst method for identifying the defects on the posterior surface. (author)

  5. 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)

  6. 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.

  7. Cone-beam computed tomography imaging: therapeutic staff dose during chemoembolisation procedure

    International Nuclear Information System (INIS)

    Cone-beam computed tomography (CBCT) imaging is an important requirement to perform real-time therapeutic image-guided procedures on patients. The purpose of this study is to estimate the personal-dose-equivalent and annual-personal-dose from CBCT imaging during transarterial chemoembolisation (TACE). Therapeutic staff doses (therapeutic and assistant physician) were collected during 200 patient (65  ±  15 years, range: 40–86) CBCT examinations over six months. Absorbed doses were assessed using thermo-luminescent dosimeters during patient hepatic TACE therapy. We estimated personal-dose-equivalent (PDE) and annual-personal-dose (APD) from absorbed dose based on international atomic energy agency protocol. APD for therapeutic procedure was calculated (therapeutic physician: 5.6 mSv; assistant physician: 5.08 mSv) based on institutional work load. Regarding PDE, the hands of the staff members received a greater dose compared to other anatomical locations (therapeutic physician: 56 mSv, 72 mSv; assistant physician: 12 mSv, 14 mSv). Annual radiation doses to the eyes and hands of the staff members were lower compared to the prescribed limits by the International Commission on Radiological Protection (ICRP). PDE and APD of both therapeutic staff members were within the recommended ICRP-103 annual limit. Dose to the assistant physician was lower than the dose to the therapeutic physician during imaging. Annual radiation doses to eye-lenses and hands of both staff members were lower than prescribed limits. (paper)

  8. Anatomy and morphology of the nasopalatine canal using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, Arpita Rai [Dept. of Oral Medicine and Radiology, Faculty of Dentistry, Jamia Millia Islamia University, New Delhi (India); Burde, Krishna; Guttai, Kruthika; Naikmasu, Venkatesh [Dept. of Oral Medicine and Radiology, S.D.M. College of Dental Sciences and Hospital, Dharwad (India)

    2013-12-15

    This study was performed to evaluate the general anatomy and morphology of the nasopalatine canal using cone-beam computed tomography (CBCT) and to determine the human anatomic variability of the nasopalatine canal in relation to age and gender. The study included 100 subjects aged between 20 and 86 years who were divided into the following 3 groups: 1) 20-34 years old; 2) 35-49 years old; 3) ≥50 years old. The subjects were equally distributed between the genders. CBCT was performed using a standard exposure and patient positioning protocol. The data of the CBCT images were sliced in three dimensions. Image planes on the three axes (X, Y, and Z) were sequentially analyzed for the location, morphology and dimensions of the nasopalatine canal by two independent observers. The correlation of age and gender with all the variables was evaluated. The present study did not reveal statistically significant differences in the number of openings at the nasal fossa; diameter of the nasal fossa openings; diameter of the incisive fossa; shape, curvature, and angulation of the canal as viewed in the sagittal sections; antero-posterior dimensions and length of the canal in the sagittal sections; or the level of division of the canal in the coronal plane by age. However, males and females showed significant differences in the length of the canal in the sagittal sections and level of the division of the canal in the coronal plane. The present study highlighted important variability observed in the anatomy and morphology of the nasopalatine canal.

  9. Poster — Thur Eve — 08: Rotational errors with on-board cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ali, E. S. M. [The Ottawa Hospital Cancer Centre, Ottawa (Canada); Webb, R. [Elekta, Ottawa (Canada); Nyiri, B. [The Ottawa Hospital Cancer Centre, Ottawa (Canada); University of Ottawa, Ottawa (Canada)

    2014-08-15

    The focus of this study is on the Elekta XVI on-board cone beam computed tomography (CBCT) system. A rotational mismatch as large as 0.5° is observed between clockwise (CW) and counter-clockwise (CCW) CBCT scans. The error could affect non-isocentric treatments (e.g., lung SBRT and acoustic neuroma), as well as off-axis organs-at-risk. The error is caused by mislabeling of the projections with a lagging gantry angle, which is caused by the finite image acquisition time and delays in the imaging system. A 30 cm diameter cylindrical phantom with 5 mm diameter holes is used for the scanning. CW and CCW scans are acquired for five gantry speeds (360 to 120 deg./min.) on six linacs from three generations (MLCi, MLCi2, and Agility). Additional scans are acquired with different x-ray pulse widths for the same mAs. In the automated CBCT analysis (using ImageJ), the CW/CCW mismatch in a series of line profiles is identified and used to calculate the rotational error. Results are consistent among all linacs and indicate that the error varies linearly with gantry speed. The finite width of the x-ray pulses is a major but predictable contributor to the delay causing the error. For 40 ms pulses, the delay is 34 ± 1 ms. A simple solution applied in our clinic is adjusting the gantry angle offset to make the CCW one-minute scans correct. A more involved approach we are currently investigating includes adjustments of pulse width and mA, resulting in focal spot changes, with potential impact on image quality.

  10. Assessment of bifid and trified mandicular canals using cone beam computed tomography

    International Nuclear Information System (INIS)

    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. 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 diameter, length, and angles were measured using PACSPLUS Viewer and ImageJ 1.46r. Statistical analysis with chi-squared and analysis of variance (ANOVA) tests was performed. Bifid and trifid mandibular canals were found in 22.6% of the 500 patients and 16.2% of the 755 sides. There was no significant difference between genders and among age groups. The retromolar canal type accounted for 71.3% of the identified canals; the dental canal type, 18.8%; the forward canal type, 4.1%; and the trifid canal type, 5.8%. Interestingly, seven cases of the trifid canal type, which has been rarely reported, were observed. The mean diameter of the bifid and trifid mandibular canals was 2.2 mm and that of the main mandibular canal was 4.3 mm. Their mean length was 16.9 mm; the mean superior angle was 149.2 degrees, and the mean inferior angle was 37.7 degrees. Bifid and trifid mandibular canals in the Korean population were observed at a relatively high rate through a CBCT evaluation, and the most common type was the retromolar canal. CBCT is suggested for a detailed evaluation of bifid and trifid mandibular canals before mandibular surgery.

  11. Anatomy and morphology of the nasopalatine canal using cone-beam computed tomography

    International Nuclear Information System (INIS)

    This study was performed to evaluate the general anatomy and morphology of the nasopalatine canal using cone-beam computed tomography (CBCT) and to determine the human anatomic variability of the nasopalatine canal in relation to age and gender. The study included 100 subjects aged between 20 and 86 years who were divided into the following 3 groups: 1) 20-34 years old; 2) 35-49 years old; 3) ≥50 years old. The subjects were equally distributed between the genders. CBCT was performed using a standard exposure and patient positioning protocol. The data of the CBCT images were sliced in three dimensions. Image planes on the three axes (X, Y, and Z) were sequentially analyzed for the location, morphology and dimensions of the nasopalatine canal by two independent observers. The correlation of age and gender with all the variables was evaluated. The present study did not reveal statistically significant differences in the number of openings at the nasal fossa; diameter of the nasal fossa openings; diameter of the incisive fossa; shape, curvature, and angulation of the canal as viewed in the sagittal sections; antero-posterior dimensions and length of the canal in the sagittal sections; or the level of division of the canal in the coronal plane by age. However, males and females showed significant differences in the length of the canal in the sagittal sections and level of the division of the canal in the coronal plane. The present study highlighted important variability observed in the anatomy and morphology of the nasopalatine canal.

  12. Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

    International Nuclear Information System (INIS)

    This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0 degrees), +10 degrees, +12 degrees, -12 degrees, and -10 degrees with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12 degrees, -0.66 to -0.11 at -10 degrees, -0.51 to +0.19 at 0 degrees, -0.64 to +0.08 at +10 degrees, and -0.64 to +0.1 at +12 degrees. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Changing the slice orientation in the range of -12 degrees to +12 degrees reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

  13. Poster — Thur Eve — 08: Rotational errors with on-board cone beam computed tomography

    International Nuclear Information System (INIS)

    The focus of this study is on the Elekta XVI on-board cone beam computed tomography (CBCT) system. A rotational mismatch as large as 0.5° is observed between clockwise (CW) and counter-clockwise (CCW) CBCT scans. The error could affect non-isocentric treatments (e.g., lung SBRT and acoustic neuroma), as well as off-axis organs-at-risk. The error is caused by mislabeling of the projections with a lagging gantry angle, which is caused by the finite image acquisition time and delays in the imaging system. A 30 cm diameter cylindrical phantom with 5 mm diameter holes is used for the scanning. CW and CCW scans are acquired for five gantry speeds (360 to 120 deg./min.) on six linacs from three generations (MLCi, MLCi2, and Agility). Additional scans are acquired with different x-ray pulse widths for the same mAs. In the automated CBCT analysis (using ImageJ), the CW/CCW mismatch in a series of line profiles is identified and used to calculate the rotational error. Results are consistent among all linacs and indicate that the error varies linearly with gantry speed. The finite width of the x-ray pulses is a major but predictable contributor to the delay causing the error. For 40 ms pulses, the delay is 34 ± 1 ms. A simple solution applied in our clinic is adjusting the gantry angle offset to make the CCW one-minute scans correct. A more involved approach we are currently investigating includes adjustments of pulse width and mA, resulting in focal spot changes, with potential impact on image quality

  14. Evaluation of condyle defects using different reconstruction protocols of cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, Luana Costa; Campos, Paulo Sergio Flores, E-mail: bastosluana@ymail.com [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Odontologia. Dept. de Radiologia Oral e Maxilofacial; Ramos-Perez, Flavia Maria de Moraes [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Fac. de Odontologia. Dept. de Clinica e Odontologia Preventiva; Pontual, Andrea dos Anjos [Universidade Federal de Pernambuco (UFPE), Camaragibe, PE (Brazil). Fac. de Odontologia. Dept. de Radiologia Oral; Almeida, Solange Maria [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Fac. de Odontologia. Dept. de Radiologia Oral

    2013-11-15

    This study was conducted to investigate how well cone-beam computed tomography (CBCT) can detect simulated cavitary defects in condyles, and to test the influence of the reconstruction protocols. Defects were created with spherical diamond burs (numbers 1013, 1016, 3017) in superior and / or posterior surfaces of twenty condyles. The condyles were scanned, and cross-sectional reconstructions were performed with nine different protocols, based on slice thickness (0.2, 0.6, 1.0 mm) and on the filters (original image, Sharpen Mild, S9) used. Two observers evaluated the defects, determining their presence and location. Statistical analysis was carried out using simple Kappa coefficient and McNemar’s test to check inter- and intra-rater reliability. The chi-square test was used to compare the rater accuracy. Analysis of variance (Tukey's test) assessed the effect of the protocols used. Kappa values for inter- and intra-rater reliability demonstrate almost perfect agreement. The proportion of correct answers was significantly higher than that of errors for cavitary defects on both condyle surfaces (p < 0.01). Only in identifying the defects located on the posterior surface was it possible to observe the influence of the 1.0 mm protocol thickness and no filter, which showed a significantly lower value. Based on the results of the current study, the technique used was valid for identifying the existence of cavities in the condyle surface. However, the protocol of a 1.0 mm-thick slice and no filter proved to be the worst method for identifying the defects on the posterior surface. (author)

  15. 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)

  16. 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.

  17. 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.

  18. A new cone-beam computed tomography system for dental applications with innovative 3D software

    Energy Technology Data Exchange (ETDEWEB)

    Pasini, Alessandro; Bianconi, D.; Rossi, A. [University of Bologna, Department of Physics, Bologna (Italy); NECTAR Imaging srl Imola (Italy); Casali, F. [University of Bologna, Department of Physics, Bologna (Italy); Bontempi, M. [CEFLA Dental Group Imola (Italy)

    2007-02-15

    Objective Cone beam computed tomography (CBCT) is an important image technique for oral surgery (dentoalveolar surgery and dental implantology) and maxillofacial applications. This technique requires compact sized scanners with a relatively low radiation dosage, which makes them suitable for imaging of the craniofacial region. This article aims to present the concept and the preliminary findings obtained with the prototype of a new CBCT scanner with dedicated 3D software, specifically designed for dental imaging. Methods The prototype implements an X-ray tube with a nominal focal spot of 0.5 mm operating at 70-100 kVp and 1-4 mA. The detector is a 6 in. image intensifier coupled with a digital CCD camera. Dosimetry was performed on a RANDO anthropomorphic phantom using Beryllium Oxide thermo-luminescent dosimeters positioned in the phantom in the following site: eyes, thyroid, skin (lips, cheeks, back of the neck), brain, mandible, maxilla and parotid glands. Doses were measured using four configurations, changing the field-of-view (4'' and 6'') and acquisition time (10 and 20 s) of the CBCT. Acquisitions were performed with different parameters regarding the x-ray tube, pixel size and acquisition geometries to evaluate image quality in relation to modulation transfer function (MTF), noise and geometric accuracy. Results The prototype was able to acquire a complete maxillofacial scan in 10-15 s. The CT reconstruction algorithm delivered images that were judged to have high quality, allowing for precise volume rendering. The radiation dose was determined to be 1-1.5 times that of the dose applied during conventional dental panoramic studies. Conclusion Preliminary studies using the CBCT prototype indicate that this device provides images with acceptable diagnostic content at a relatively low radiation dosage, if compared to systems currently available on the market. (orig.)

  19. Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

    Energy Technology Data Exchange (ETDEWEB)

    Nikneshan, Nikneshan; Aval, Shadi Hamidi [Dept. of Dental and Maxillofacial Radiology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Bakhshalian, Neema [Dept. of Advanced Periodontology, School of Dentistry, University of Southern California, Los Angeles (United States); Shahab, Shahriyar [Dept. of Dental and Maxillofacial Radiology, School of Dentistry, Shahed University of Medical Sciences, Tehran (Korea, Republic of); Mohammadpour, Mahdis [Dept. of Dental and Maxillofacial Radiology, School of Dentistry, Qazvin University of Medical Sciences, Qazvin (Iran, Islamic Republic of); SarikhanI, Soodeh [Dept. of Dental and Maxillofacial Radiology, School of Dentistry, Golestan University of Medical Sciences, Golestan (Iran, Islamic Republic of)

    2014-12-15

    This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0 degrees), +10 degrees, +12 degrees, -12 degrees, and -10 degrees with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12 degrees, -0.66 to -0.11 at -10 degrees, -0.51 to +0.19 at 0 degrees, -0.64 to +0.08 at +10 degrees, and -0.64 to +0.1 at +12 degrees. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Changing the slice orientation in the range of -12 degrees to +12 degrees reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

  20. Nutrient canals on mandibular anterior region in cone beam computed tomography

    International Nuclear Information System (INIS)

    To evaluate location, distribution, diameter, and length of the nutrient canals on mandibular anterior region using a cone beam computed tomography (CBCT). Mandibular CBCT was performed on 33 adults (18 males and 15 female) with no history of systemic disease, and any other dental surgery history. Location, distribution, diameter, and length of the nutrient canals on mandibular anterior region were radiographically evaluated. A statistical comparison was done by SPSS. In the location and distribution of nutrient canals, they were found in 6.8% at labial portion above root apex, in 93.28% at lingual portion above root apex in 46.2% at labial portion below root apex, and in 53.6% at lingual portion below root apex. Nutrient canals at lingual portion above root apex were most frequently observed between central and lateral incisors, and those at labial and lingual portion below root apex were most frequently observed between central incisors. The mean diameters of nutrient canals were 0.54 mm at labial portion above root apex, 0.61 mm at lingual portion above root apex, 0.66 mm at labial portion below root apex, and 0.76 mm at lingual portion below root apex. The mean lengths of nutrient canals were 2.63 mm at labial portion above root apex, 3.74 mm at lingual portion above root apex, 4.51 mm at labial portion below root apex, and 6.77 mm at lingual portion below root apex. CBCT is useful device to evaluate the anatomical structure of nutrient canals on mandibular anterior region

  1. Assessment of bifid and trified mandicular canals using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rashsyren, Oyuntugs [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Mongolian National University Medical Science, Ulaanbaatar (United States); Choi, Jin Woo; Han, Won Jeong; Kim Eun Kyung [Dept. of Oral and Maxillofacial Radiology, Dankook University College of Dentistry, Cheonan (Korea, Republic of)

    2014-09-15

    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. 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 diameter, length, and angles were measured using PACSPLUS Viewer and ImageJ 1.46r. Statistical analysis with chi-squared and analysis of variance (ANOVA) tests was performed. Bifid and trifid mandibular canals were found in 22.6% of the 500 patients and 16.2% of the 755 sides. There was no significant difference between genders and among age groups. The retromolar canal type accounted for 71.3% of the identified canals; the dental canal type, 18.8%; the forward canal type, 4.1%; and the trifid canal type, 5.8%. Interestingly, seven cases of the trifid canal type, which has been rarely reported, were observed. The mean diameter of the bifid and trifid mandibular canals was 2.2 mm and that of the main mandibular canal was 4.3 mm. Their mean length was 16.9 mm; the mean superior angle was 149.2 degrees, and the mean inferior angle was 37.7 degrees. Bifid and trifid mandibular canals in the Korean population were observed at a relatively high rate through a CBCT evaluation, and the most common type was the retromolar canal. CBCT is suggested for a detailed evaluation of bifid and trifid mandibular canals before mandibular surgery.

  2. A cone-beam computed tomography evaluation of buccal bone thickness following maxillary expansion

    International Nuclear Information System (INIS)

    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.

  3. 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.

  4. Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography

    International Nuclear Information System (INIS)

    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)

  5. Vertical bone measurements from cone beam computed tomography images using different software packages

    International Nuclear Information System (INIS)

    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)

  6. A new cone-beam computed tomography system for dental applications with innovative 3D software

    International Nuclear Information System (INIS)

    Objective Cone beam computed tomography (CBCT) is an important image technique for oral surgery (dentoalveolar surgery and dental implantology) and maxillofacial applications. This technique requires compact sized scanners with a relatively low radiation dosage, which makes them suitable for imaging of the craniofacial region. This article aims to present the concept and the preliminary findings obtained with the prototype of a new CBCT scanner with dedicated 3D software, specifically designed for dental imaging. Methods The prototype implements an X-ray tube with a nominal focal spot of 0.5 mm operating at 70-100 kVp and 1-4 mA. The detector is a 6 in. image intensifier coupled with a digital CCD camera. Dosimetry was performed on a RANDO anthropomorphic phantom using Beryllium Oxide thermo-luminescent dosimeters positioned in the phantom in the following site: eyes, thyroid, skin (lips, cheeks, back of the neck), brain, mandible, maxilla and parotid glands. Doses were measured using four configurations, changing the field-of-view (4'' and 6'') and acquisition time (10 and 20 s) of the CBCT. Acquisitions were performed with different parameters regarding the x-ray tube, pixel size and acquisition geometries to evaluate image quality in relation to modulation transfer function (MTF), noise and geometric accuracy. Results The prototype was able to acquire a complete maxillofacial scan in 10-15 s. The CT reconstruction algorithm delivered images that were judged to have high quality, allowing for precise volume rendering. The radiation dose was determined to be 1-1.5 times that of the dose applied during conventional dental panoramic studies. Conclusion Preliminary studies using the CBCT prototype indicate that this device provides images with acceptable diagnostic content at a relatively low radiation dosage, if compared to systems currently available on the market. (orig.)

  7. Cone-Beam Computed Tomography Correlates with Conventional Helical Computed Tomography in Evaluation of Lipiodol Accumulation in HCC after Chemoembolization.

    Directory of Open Access Journals (Sweden)

    Toru Ishikawa

    Full Text Available The amount of drug-loaded lipiodol in an HCC tumor post-transarterial chemoembolization (TACE correlates with the risk of local tumor recurrence. Lipiodol enhancement of a tumor on conventional CT, measured in Hounsfield units (HU, can predict tumor response. Here we investigate whether cone-beam CT (CBCT can also be used to predict tumor response, providing the benefit of being able to optimize the patient's treatment plan intra-procedurally.A total of 82 HCC nodules (82 patients, ≤5 cm in diameter, were treated with balloon-occluded TACE using miriplatin between December 2013 and November 2014. For each patient, both CBCT and conventional CT images were obtained post-TACE. The degree of correlation between CBCT and conventional CT was determined by comparing identical regions of interest for each imaging modality using pixel values.The pixel values from conventional CT and CBCT were highly correlated, with a Pearson correlation coefficient of 0.912 (p<0.001. The location of the nodules within the liver did not affect the results; the correlation coefficient was 0.891 (p<0.001 for the left lobe and 0.926 (p<0.001 for the right lobe. The mean pixel value for conventional CT was 439 ± 279 HU, and the mean pixel value for CBCT was 416 ± 311 HU.CBCT may be used as a substitute for conventional CT to quantitatively evaluate the amount of drug-loaded lipiodol within an HCC nodule and, hence, the efficacy of TACE treatment. The major benefit of using CBCT is the ability to predict the likelihood of local recurrence intra-procedurally, enabling subsequent treatment optimization.

  8. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  9. Clinical Implementation of Intrafraction Cone Beam Computed Tomography Imaging During Lung Tumor Stereotactic Ablative Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To develop and clinically evaluate a volumetric imaging technique for assessing intrafraction geometric and dosimetric accuracy of stereotactic ablative radiation therapy (SABR). Methods and Materials: Twenty patients received SABR for lung tumors using volumetric modulated arc therapy (VMAT). At the beginning of each fraction, pretreatment cone beam computed tomography (CBCT) was used to align the soft-tissue tumor position with that in the planning CT. Concurrent with dose delivery, we acquired fluoroscopic radiograph projections during VMAT using the Varian on-board imaging system. Those kilovolt projections acquired during millivolt beam-on were automatically extracted, and intrafraction CBCT images were reconstructed using the filtered backprojection technique. We determined the time-averaged target shift during VMAT by calculating the center of mass of the tumor target in the intrafraction CBCT relative to the planning CT. To estimate the dosimetric impact of the target shift during treatment, we recalculated the dose to the GTV after shifting the entire patient anatomy according to the time-averaged target shift determined earlier. Results: The mean target shift from intrafraction CBCT to planning CT was 1.6, 1.0, and 1.5 mm; the 95th percentile shift was 5.2, 3.1, 3.6 mm; and the maximum shift was 5.7, 3.6, and 4.9 mm along the anterior-posterior, left-right, and superior-inferior directions. Thus, the time-averaged intrafraction gross tumor volume (GTV) position was always within the planning target volume. We observed some degree of target blurring in the intrafraction CBCT, indicating imperfect breath-hold reproducibility or residual motion of the GTV during treatment. By our estimated dose recalculation, the GTV was consistently covered by the prescription dose (PD), that is, V100% above 0.97 for all patients, and minimum dose to GTV >100% PD for 18 patients and >95% PD for all patients. Conclusions: Intrafraction CBCT during VMAT can provide

  10. Clinical Implementation of Intrafraction Cone Beam Computed Tomography Imaging During Lung Tumor Stereotactic Ablative Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruijiang; Han, Bin; Meng, Bowen [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Maxim, Peter G.; Xing, Lei; Koong, Albert C. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Diehn, Maximilian, E-mail: Diehn@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States); Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California (United States); Loo, Billy W., E-mail: BWLoo@Stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California (United States)

    2013-12-01

    Purpose: To develop and clinically evaluate a volumetric imaging technique for assessing intrafraction geometric and dosimetric accuracy of stereotactic ablative radiation therapy (SABR). Methods and Materials: Twenty patients received SABR for lung tumors using volumetric modulated arc therapy (VMAT). At the beginning of each fraction, pretreatment cone beam computed tomography (CBCT) was used to align the soft-tissue tumor position with that in the planning CT. Concurrent with dose delivery, we acquired fluoroscopic radiograph projections during VMAT using the Varian on-board imaging system. Those kilovolt projections acquired during millivolt beam-on were automatically extracted, and intrafraction CBCT images were reconstructed using the filtered backprojection technique. We determined the time-averaged target shift during VMAT by calculating the center of mass of the tumor target in the intrafraction CBCT relative to the planning CT. To estimate the dosimetric impact of the target shift during treatment, we recalculated the dose to the GTV after shifting the entire patient anatomy according to the time-averaged target shift determined earlier. Results: The mean target shift from intrafraction CBCT to planning CT was 1.6, 1.0, and 1.5 mm; the 95th percentile shift was 5.2, 3.1, 3.6 mm; and the maximum shift was 5.7, 3.6, and 4.9 mm along the anterior-posterior, left-right, and superior-inferior directions. Thus, the time-averaged intrafraction gross tumor volume (GTV) position was always within the planning target volume. We observed some degree of target blurring in the intrafraction CBCT, indicating imperfect breath-hold reproducibility or residual motion of the GTV during treatment. By our estimated dose recalculation, the GTV was consistently covered by the prescription dose (PD), that is, V100% above 0.97 for all patients, and minimum dose to GTV >100% PD for 18 patients and >95% PD for all patients. Conclusions: Intrafraction CBCT during VMAT can provide

  11. Late enhancement of the left ventricular myocardium in young patients with hypertrophic cardiomyopathy by electron beam computed tomography

    International Nuclear Information System (INIS)

    In the assessment of myocardial characteristics with computed tomography, late enhancement (intense stain in delayed phase image of contrast enhancement) is an abnormal finding and thought to represent fibrotic change. The purpose of this study was to investigate the clinical importance of late enhancement in young patients with hypertrophic cardiomyopathy. Forty-five patients with hypertrophic cardiomyopathy, aged 1 to 24 years, were examined by electron beam computed tomography. We also assessed the clinical data on these patients. Late enhancement was found in 29 (64%) patients, usually as a patchy, stained area in the myocardium. In 29 patients with late enhancement, seven (24%) has syncopal episode and seven (24%) had a family history of sudden death. In contrast, none (0%) of 16 patients without late enhancement had syncopal episode nor a family history of sudden death (p<0.05). Twenty-four hour electrocardiographic monitoring was performed for 31 patients. Al patients with ventricular tachycardia were in the group with late enhancement [10/23 (43%) vs 0/8 (0%), p<0.05]. Thirty-seven patients were examined by thallium scintigraphy. The perfusion defect was more frequently found in patients with late enhancement than in patients without [14/26 (54%) vs 2/11 (18%), p<0.05]. These data suggest that late enhancement shown with electron beam computed tomography is related to syncopal episode, family history of sudden death, ventricular tachycardia, and myocardial damage in young patients with hypertrophic cardiomyopathy. (author)

  12. Imaging a moving lung tumor with megavoltage cone beam computed tomography

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    Gayou, Olivier, E-mail: ogayou@wpahs.org; Colonias, Athanasios [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 and Allegheny Campus, Temple University School of Medicine, Pittsburgh, Pennsylvania 15212 (United States)

    2015-05-15

    Purpose: Respiratory motion may affect the accuracy of image guidance of radiation treatment of lung cancer. A cone beam computed tomography (CBCT) image spans several breathing cycles, resulting in a blurred object with a theoretical size equal to the sum of tumor size and breathing motion. However, several factors may affect this theoretical relationship. The objective of this study was to analyze the effect of tumor motion on megavoltage (MV)-CBCT images, by comparing target sizes on simulation and pretreatment images of a large cohort of lung cancer patients. Methods: Ninety-three MV-CBCT images from 17 patients were analyzed. Internal target volumes were contoured on each MV-CBCT dataset [internal target volume (ITV{sub CB})]. Their extent in each dimension was compared to that of two volumes contoured on simulation 4-dimensional computed tomography (4D-CT) images: the combination of the tumor contours of each phase of the 4D-CT (ITV{sub 4D}) and the volume contoured on the average CT calculated from the 4D-CT phases (ITV{sub ave}). Tumor size and breathing amplitude were assessed by contouring the tumor on each CBCT raw projection where it could be unambiguously identified. The effect of breathing amplitude on the quality of the MV-CBCT image reconstruction was analyzed. Results: The mean differences between the sizes of ITV{sub CB} and ITV{sub 4D} were −1.6 ± 3.3 mm (p < 0.001), −2.4 ± 3.1 mm (p < 0.001), and −7.2 ± 5.3 mm (p < 0.001) in the anterior/posterior (AP), left/right (LR), and superior/inferior (SI) directions, respectively, showing that MV-CBCT underestimates the full target size. The corresponding mean differences between ITV{sub CB} and ITV{sub ave} were 0.3 ± 2.6 mm (p = 0.307), 0.0 ± 2.4 mm (p = 0.86), and −4.0 ± 4.3 mm (p < 0.001), indicating that the average CT image is more representative of what is visible on MV-CBCT in the AP and LR directions. In the SI directions, differences between ITV{sub CB} and ITV{sub ave} could be

  13. Correction for patient table-induced scattered radiation in cone-beam computed tomography (CBCT)

    Energy Technology Data Exchange (ETDEWEB)

    Sun Mingshan; Nagy, Tamas; Virshup, Gary; Partain, Larry; Oelhafen, Markus; Star-Lack, Josh [Ginzton Technology Center, Varian Medical Systems, 3120 Hansen Way, Palo Alto, California 94304 (United States); Imaging Laboratory, Varian Medical Systems, Tafernstrasse 7, CH-5405 Baden-Dattwil (Switzerland); Ginzton Technology Center, Varian Medical Systems, 3120 Hansen Way, Palo Alto, California 94304 (United States); Imaging Laboratory, Varian Medical Systems, Tafernstrasse 7, CH-5405 Baden-Dattwil (Switzerland); Ginzton Technology Center, Varian Medical Systems, 3120 Hansen Way, Palo Alto, California 94304 (United States)

    2011-04-15

    Purpose: In image-guided radiotherapy, an artifact typically seen in axial slices of x-ray cone-beam computed tomography (CBCT) reconstructions is a dark region or ''black hole'' situated below the scan isocenter. The authors trace the cause of the artifact to scattered radiation produced by radiotherapy patient tabletops and show it is linked to the use of the offset-detector acquisition mode to enlarge the imaging field-of-view. The authors present a hybrid scatter kernel superposition (SKS) algorithm to correct for scatter from both the object-of-interest and the tabletop. Methods: Monte Carlo simulations and phantom experiments were first performed to identify the source of the black hole artifact. For correction, a SKS algorithm was developed that uses separate kernels to estimate scatter from the patient tabletop and the object-of-interest. Each projection is divided into two regions, one defined by the shadow cast by the tabletop on the imager and one defined by the unshadowed region. The region not shadowed by the tabletop is processed using the recently developed fast adaptive scatter kernel superposition (fASKS) method which employs asymmetric kernels that best model scatter transport through bodylike objects. The shadowed region is convolved with a combination of slab-derived symmetric SKS kernels and asymmetric fASKS kernels. The composition of the hybrid kernels is projection-angle-dependent. To test the algorithm, pelvis phantom and in vivo data were acquired using a CBCT test stand, a Varian Acuity simulator, and a Varian On-Board Imager, all of which have similar geometries and components. Artifact intensities and Hounsfield unit (HU) accuracies in the reconstructions were assessed before and after the correction. Results: The hybrid kernel algorithm provided effective correction and produced substantially better scatter estimates than the symmetric SKS or asymmetric fASKS methods alone. HU nonuniformities in the reconstructed

  14. Impact of Immobilization on Intrafraction Motion for Spine Stereotactic Body Radiotherapy Using Cone Beam Computed Tomography

    International Nuclear Information System (INIS)

    Purpose: Spine stereotactic body radiotherapy (SBRT) involves tight planning margins and steep dose gradients to the surrounding organs at risk (OAR). This study aimed to assess intrafraction motion using cone beam computed tomography (CBCT) for spine SBRT patients treated using three immobilization devices. Methods and Materials: Setup accuracy using CBCT was retrospectively analyzed for 102 treated spinal metastases in 84 patients. Thoracic and lumbar spine patients were immobilized with either an evacuated cushion (EC, n = 24) or a semirigid vacuum body fixation (BF, n = 60). For cases treated at cervical/upper thoracic (thoracic [T]1–T3) vertebrae, a thermoplastic S-frame (SF) mask (n = 18) was used. Patient setup was corrected by using bony anatomy image registration and couch translations only (no rotation corrections) with shifts confirmed on verification CBCTs. Repeat imaging was performed mid- and post-treatment. Patient translational and rotational positioning data were recorded to calculate means, standard deviations (SD), and corresponding margins ± 2 SD for residual setup errors and intrafraction motion. Results: A total of 355 localizations, 333 verifications, and 248 mid- and 280 post-treatment CBCTs were analyzed. Residual translations and rotations after couch corrections (verification scans) were similar for all immobilization systems, with SDs of 0.6 to 0.9 mm in any direction and 0.9° to 1.6°, respectively. Margins to encompass residual setup errors after couch corrections were within 2 mm. Including intrafraction motion, as measured on post-treatment CBCTs, SDs for total setup error in the left-right, cranial-caudal, and anterior-posterior directions were 1.3, 1.2, and 1.0 mm for EC; 0.9, 0.7, and 0.9 mm for BF; and 1.3, 0.9, and 1.1 mm for SF, respectively. The calculated margins required to encompass total setup error increased to 3 mm for EC and SF and remained within 2 mm for BF. Conclusion: Following image guidance, residual setup

  15. Assessment of equivalent dose on the lens in cone beam computed tomography

    International Nuclear Information System (INIS)

    The Cone Beam Computed Tomography (CBCT) is presented as a useful test method for the evaluation of craniofacial structures. Among them stands the temporomandibular joint (T MJ) imaging as complementary to clinical evaluation. It must be considered that there is no reference levels established for diagnosis of this imaging modality. In this same context, recently the limit for crystalline lens was reviewed by ICRP which set new values to the equivalent dose. The aim of this study was to evaluate the kerma at the surface of the crystalline lens in T MJ CBCT and derive the equivalent dose. It was used an anthropomorphic phantom of the head and neck (manufactured by: Radiation Support Devices, model; Rs-230) containing equivalent tissue with dimensions of a typical patient. The dosimetric measurements were obtained by using seven pairs of thermoluminescent dosimetry (TLD) dosimeters (LiF: Mg, Ti) positioned on the surface of the crystalline lens, divided into two pairs (one pair for each eye) per scanner evaluated. The tomographic images were obtained in three CBCT equipment s (Kodak 9000, Gendex GXCB 500 and i-Cat). Values of equivalent dose obtained were: 5.82 mSv (Kodak 9000); 5.38 mSv (Gendex GXCB 500) and 7.98 mSv (i-Cat). These results demonstrate that for this type of procedure the doses are below the annual limit but may vary in accordance with the scanner and the exposure factors used in the image acquisition. The Gendex GXCB500 uses larger Fov and higher kV. It results in levels close to those obtained on Kodak 9000. Larger doses are associated with the i-Cat. Another factor that rises is the repetition of examinations due to positioning errors and / or patient movement, which may exceed the annual limit established by ICRP. Although the ICRP limits are not applied to medical exposures, it is advisable to consider the sensitivity of the organ. For this reason, it is concluded that doses per T MJ procedure on CBCT are below the annual limit and may vary

  16. Assessment of mandibular posterior regional landmarks using cone-beam computed tomography in dental implant surgery.

    Science.gov (United States)

    de Souza, Lílian Azevedo; Souza Picorelli Assis, Neuza Maria; Ribeiro, Rosangela Almeida; Pires Carvalho, Antônio Carlos; Devito, Karina Lopes

    2016-05-01

    The aim of this study has been to evaluate and correlate the anatomical features of the posterior mandibular region (submandibular fossa depth, bone height and thickness, and mandibular canal corticalization) to improve accident prevention and allow safe planning in implantology. Four parasagittal sections of cone-beam computed tomography (CBCT) from 100 patients were bilaterally analyzed. Linear measurements of the submandibular fossa depth, bone height and thickness were performed. The submandibular fossa was also classified into non-influential undercuts and influential undercuts for implant placement. Mandibular canal corticalization was also evaluated and classified according to the visualization. Data on patient age and gender were also collected. Forty-one scans (41%) were from male patients, and 59 (59%) were from female patients. Patient age ranged between 18 and 84 years, with an average age of 51.37 years. The submandibular fossa depth and implant bone thickness had a significant effect on the variability of the sample (46.1% and 22.3%, respectively). The submandibular fossa depth was quite variable, and the highest values were observed in the posterior regions. In 18.27% of the cases, the presence of the fossa directly influenced implant placement, considering a bone height of 10mm (standard implant). A significant correlation was observed between fossa depth and bone thickness. Thus, greater attention should be paid to thick ridges; although thick ridges are favorable, they may be associated with deeper submandibular fossae. The mandibular canal was the most influential anatomical structure in the premolar region due to the reduced bone height in this region and the greater difficulty in viewing the canal, and the submandibular fossa was the most influential structure in the molar region due to lower bone height leading up to the fossa and the greater fossa depth in this region. Therefore, CBCT is an important tool for assessing the mandibular region

  17. Assessment of equivalent dose on the lens in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M. V. L.; Campos, P. S. F. [Federal University of Bahia, Department of Health Sciences, Salvador (Brazil); Andrade, M. E. A. [Federal University of Pernambuco, Department of Nuclear Energy, Recife (Brazil); Soares, M. R. [Federal University of Sergipe, Department of Physics, Sao Cristovao (Brazil); Batista, W. O., E-mail: marcusradiology@gmail.com [Federal Institute of Bahia, Department of Applied Sciences, 40.301-015 Salvador (Brazil)

    2014-08-15

    The Cone Beam Computed Tomography (CBCT) is presented as a useful test method for the evaluation of craniofacial structures. Among them stands the temporomandibular joint (T MJ) imaging as complementary to clinical evaluation. It must be considered that there is no reference levels established for diagnosis of this imaging modality. In this same context, recently the limit for crystalline lens was reviewed by ICRP which set new values to the equivalent dose. The aim of this study was to evaluate the kerma at the surface of the crystalline lens in T MJ CBCT and derive the equivalent dose. It was used an anthropomorphic phantom of the head and neck (manufactured by: Radiation Support Devices, model; Rs-230) containing equivalent tissue with dimensions of a typical patient. The dosimetric measurements were obtained by using seven pairs of thermoluminescent dosimetry (TLD) dosimeters (LiF: Mg, Ti) positioned on the surface of the crystalline lens, divided into two pairs (one pair for each eye) per scanner evaluated. The tomographic images were obtained in three CBCT equipment s (Kodak 9000, Gendex GXCB 500 and i-Cat). Values of equivalent dose obtained were: 5.82 mSv (Kodak 9000); 5.38 mSv (Gendex GXCB 500) and 7.98 mSv (i-Cat). These results demonstrate that for this type of procedure the doses are below the annual limit but may vary in accordance with the scanner and the exposure factors used in the image acquisition. The Gendex GXCB500 uses larger Fov and higher kV. It results in levels close to those obtained on Kodak 9000. Larger doses are associated with the i-Cat. Another factor that rises is the repetition of examinations due to positioning errors and / or patient movement, which may exceed the annual limit established by ICRP. Although the ICRP limits are not applied to medical exposures, it is advisable to consider the sensitivity of the organ. For this reason, it is concluded that doses per T MJ procedure on CBCT are below the annual limit and may vary

  18. Estimation of Rectal Dose Using Daily Megavoltage Cone-Beam Computed Tomography and Deformable Image Registration

    International Nuclear Information System (INIS)

    Purpose: The actual dose delivered to critical organs will differ from the simulated dose because of interfractional organ motion and deformation. Here, we developed a method to estimate the rectal dose in prostate intensity modulated radiation therapy with consideration to interfractional organ motion using daily megavoltage cone-beam computed tomography (MVCBCT). Methods and Materials: Under exemption status from our institutional review board, we retrospectively reviewed 231 series of MVCBCT of 8 patients with prostate cancer. On both planning CT (pCT) and MVCBCT images, the rectal contours were delineated and the CT value within the contours was replaced by the mean CT value within the pelvis, with the addition of 100 Hounsfield units. MVCBCT images were rigidly registered to pCT and then nonrigidly registered using B-Spline deformable image registration (DIR) with Velocity AI software. The concordance between the rectal contours on MVCBCT and pCT was evaluated using the Dice similarity coefficient (DSC). The dose distributions normalized for 1 fraction were also deformed and summed to estimate the actual total dose. Results: The DSC of all treatment fractions of 8 patients was improved from 0.75±0.04 (mean ±SD) to 0.90 ±0.02 by DIR. Six patients showed a decrease of the generalized equivalent uniform dose (gEUD) from total dose compared with treatment plans. Although the rectal volume of each treatment fraction did not show any correlation with the change in gEUD (R2=0.18±0.13), the displacement of the center of gravity of rectal contours in the anterior-posterior (AP) direction showed an intermediate relationship (R2=0.61±0.16). Conclusion: We developed a method for evaluation of rectal dose using DIR and MVCBCT images and showed the necessity of DIR for the evaluation of total dose. Displacement of the rectum in the AP direction showed a greater effect on the change in rectal dose compared with the rectal volume

  19. Regional pulmonary blood flow measurement in humans with electron beam computed tomography

    International Nuclear Information System (INIS)

    Electron beam computed tomography (EBCT) is a potentially useful modality to quantitate regional pulmonary flow (RPF) with minimal invasiveness, in part because it has good spatial and temporal resolution. The present studies used a single compartment model of indicator transport and EBCT to measure regional tissue flow in the lungs of human subjects. The model postulates that flow is proportional to maximal enhancement and assumes complete tissue accumulation of indicator before significant indicator washout (WO). EBCT flow studies were retrospectively analyzed with respect to regional pulmonary flow (RPF) in 10 adult patients who had undergone clinically indicated or research cardiovascular studies. Time density curves from the left atrial (LA) cavity and one-third segments of left (LL) and right (RL) lungs (A: anterior, M: middle and P: posterior segments) were used to calculate RPF. Washout was determined as the percent of the LA curve at the time of peak parenchymal opacification using gamma curve fits to both tissue data and the LA curve data. Mean ± standard deviation RPF in ml/min/ml was 0.8 ± 0.4, 1.1 ± 0.4 and 1.3 ± 0.4 for A, M and P respectively for one-third regions in the left lung. Similar results were found in the right lung. No difference in RPF was found when images were measured either by including the largest of visible parenchymal vessels or when such vessels were excluded. Flow in A of LL and RL was less than that in M or P. Average WO was about 10%, with a range of 0--41% of the LA curve area. There was no significant difference between one-third segment WO using pairwise comparison on the left and right sides when tested separately. RPF values were greater in the posterior vs anterior regions of these supine patients. In conclusion, EBCT can detect gravity related flow differences in the human lung. EBCT has potential for clinical assessment of absolute regional pulmonary flow determination in animals and man

  20. Cone beam computed tomography imaging as a primary diagnostic tool for computer-guided surgery and CAD-CAM interim removable and fixed dental prostheses.

    Science.gov (United States)

    Charette, Jyme R; Goldberg, Jack; Harris, Bryan T; Morton, Dean; Llop, Daniel R; Lin, Wei-Shao

    2016-08-01

    This article describes a digital workflow using cone beam computed tomography imaging as the primary diagnostic tool in the virtual planning of the computer-guided surgery and fabrication of a maxillary interim complete removable dental prosthesis and mandibular interim implant-supported complete fixed dental prosthesis with computer-aided design and computer-aided manufacturing technology. Diagnostic impressions (conventional or digital) and casts are unnecessary in this proposed digital workflow, providing clinicians with an alternative treatment in the indicated clinical scenario. PMID:27086108

  1. Accuracy of Digital Radiography and Cone Beam Computed Tomography on Periapical Radiolucency Detection in Endodontically Treated Teeth

    Directory of Open Access Journals (Sweden)

    Tadas Venskutonis

    2014-07-01

    Full Text Available Objectives: The aim of the present study was to compare the accuracy of intraoral digital periapical radiography and cone beam computed tomography in the detection of periapical radiolucencies in endodontically treated teeth. Material and Methods: Radiographic images (cone beam computed tomography [CBCT] scans and digital periapical radiography [PR] images from 60 patients, achieved from September 2008 to July 2013, were retrieved from databases of the Department of Oral Diseases, Lithuanian University of Health Sciences. Twenty patients met inclusion criteria and were selected for further evaluation. Results: In 20 patients (42.4 [SD 12.1] years, 65% men and 35% women a total of 35 endodontically treated teeth (1.75 [SD 0.91]; 27 in maxilla and 8 in mandible were evaluated. Overall, it was observed a statistical significant difference between the number of periapical lesions observed in the CBCT (n = 42 and radiographic (n = 24 examinations (P < 0.05. In molar teeth, CBCT identify a significantly higher amount of periapical lesions than with the radiographic method (P < 0.05. There were significant differences between CBCT and PR in the mean number of lesions identified per tooth (1.2 vs 0.66, P = 0.03, number of teeth with lesions (0.71 vs 0.46, P = 0.03 and number of lesions identified per canal (0.57 vs 0.33, P = 0.005. Considering CBCT as “gold standard” in lesion detection with the sensitivity, specificity and accuracy considering as score 1, then the same parameters of PR were 0.57, 1 and 0.76 respectively. Conclusions: Within the limitations of the present study, it can be concluded that cone beam computed tomography scans were more accurate compared to digital periapical radiographs for detecting periapical radiolucencies in endodontically treated teeth. The difference was more pronounced in molar teeth.

  2. Adaptive-Predictive Organ Localization Using Cone-Beam Computed Tomography for Improved Accuracy in External Beam Radiotherapy for Bladder Cancer

    International Nuclear Information System (INIS)

    Purpose: To examine patterns of bladder wall motion during high-dose hypofractionated bladder radiotherapy and to validate a novel adaptive planning method, A-POLO, to prevent subsequent geographic miss. Methods and Materials: Patterns of individual bladder filling were obtained with repeat computed tomography planning scans at 0, 15, and 30 minutes after voiding. A series of patient-specific plans corresponding to these time-displacement points was created. Pretreatment cone-beam computed tomography was performed before each fraction and assessed retrospectively for adaptive intervention. In fractions that would have required intervention, the most appropriate plan was chosen from the patient's 'library,' and the resulting target coverage was reassessed with repeat cone-beam computed tomography. Results: A large variation in patterns of bladder filling and interfraction displacement was seen. During radiotherapy, predominant translations occurred cranially (maximum 2.5 cm) and anteriorly (maximum 1.75 cm). No apparent explanation was found for this variation using pretreatment patient factors. A need for adaptive planning was demonstrated by 51% of fractions, and 73% of fractions would have been delivered correctly using A-POLO. The adaptive strategy improved target coverage and was able to account for intrafraction motion also. Conclusions: Bladder volume variation will result in geographic miss in a high proportion of delivered bladder radiotherapy treatments. The A-POLO strategy can be used to correct for this and can be implemented from the first fraction of radiotherapy; thus, it is particularly suited to hypofractionated bladder radiotherapy regimens.

  3. Image Registration of Cone-Beam Computer Tomography and Preprocedural Computer Tomography Aids in Localization of Adrenal Veins and Decreasing Radiation Dose in Adrenal Vein Sampling

    International Nuclear Information System (INIS)

    PurposeWe assessed whether image registration of cone-beam computed tomography (CT) (CBCT) and contrast-enhanced CT (CE-CT) images indicating the locations of the adrenal veins can aid in increasing the success rate of first-attempts adrenal vein sampling (AVS) and therefore decreasing patient radiation dose.Materials and Methods CBCT scans were acquired in the interventional suite (Philips Allura Xper FD20) and rigidly registered to the vertebra in previously acquired CE-CT. Adrenal vein locations were marked on the CT image and superimposed with live fluoroscopy and digital-subtraction angiography (DSA) to guide the AVS. Seventeen first attempts at AVS were performed with image registration and retrospectively compared with 15 first attempts without image registration performed earlier by the same 2 interventional radiologists. First-attempt AVS was considered successful when both adrenal vein samples showed representative cortisol levels. Sampling time, dose-area product (DAP), number of DSA runs, fluoroscopy time, and skin dose were recorded.ResultsWithout image registration, the first attempt at sampling was successful in 8 of 15 procedures indicating a success rate of 53.3 %. This increased to 76.5 % (13 of 17) by adding CBCT and CE-CT image registration to AVS procedures (p = 0.266). DAP values (p = 0.001) and DSA runs (p = 0.026) decreased significantly by adding image registration guidance. Sampling and fluoroscopy times and skin dose showed no significant changes.ConclusionGuidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required

  4. Image Registration of Cone-Beam Computer Tomography and Preprocedural Computer Tomography Aids in Localization of Adrenal Veins and Decreasing Radiation Dose in Adrenal Vein Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Busser, Wendy M. H., E-mail: wendy.busser@radboudumc.nl; Arntz, Mark J.; Jenniskens, Sjoerd F. M. [Radboud University Medical Center, Department of Radiology, Section of Interventional Radiology (Netherlands); Deinum, Jaap [Radboud University Medical Center, Department of General Internal Medicine (Netherlands); Hoogeveen, Yvonne L.; Lange, Frank de; Schultze Kool, Leo J. [Radboud University Medical Center, Department of Radiology, Section of Interventional Radiology (Netherlands)

    2015-08-15

    PurposeWe assessed whether image registration of cone-beam computed tomography (CT) (CBCT) and contrast-enhanced CT (CE-CT) images indicating the locations of the adrenal veins can aid in increasing the success rate of first-attempts adrenal vein sampling (AVS) and therefore decreasing patient radiation dose.Materials and Methods CBCT scans were acquired in the interventional suite (Philips Allura Xper FD20) and rigidly registered to the vertebra in previously acquired CE-CT. Adrenal vein locations were marked on the CT image and superimposed with live fluoroscopy and digital-subtraction angiography (DSA) to guide the AVS. Seventeen first attempts at AVS were performed with image registration and retrospectively compared with 15 first attempts without image registration performed earlier by the same 2 interventional radiologists. First-attempt AVS was considered successful when both adrenal vein samples showed representative cortisol levels. Sampling time, dose-area product (DAP), number of DSA runs, fluoroscopy time, and skin dose were recorded.ResultsWithout image registration, the first attempt at sampling was successful in 8 of 15 procedures indicating a success rate of 53.3 %. This increased to 76.5 % (13 of 17) by adding CBCT and CE-CT image registration to AVS procedures (p = 0.266). DAP values (p = 0.001) and DSA runs (p = 0.026) decreased significantly by adding image registration guidance. Sampling and fluoroscopy times and skin dose showed no significant changes.ConclusionGuidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required.

  5. Applications of linac-mounted kilovoltage Cone-beam Computed Tomography in modern radiation therapy: A review

    International Nuclear Information System (INIS)

    The use of Cone-beam Computed Tomography (CBCT) in radiotherapy is increasing due to the widespread implementation of kilovoltage systems on the currently available linear accelerators. Cone beam CT acts as an effective Image-Guided Radiotherapy (IGRT) tool for the verification of patient position. It also opens up the possibility of real-time re-optimization of treatment plans for Adaptive Radiotherapy (ART). This paper reviews the most prominent applications of CBCT (linac-mounted) in radiation therapy, focusing on CBCT-based planning and dose calculation studies. This is followed by a concise review of the main issues associated with CBCT, such as imaging artifacts, dose and image quality. It explores how medical physicists and oncologists can best apply CBCT for therapeutic applications

  6. Comparison of the accuracy of electron-beam computed tomography and conventional cineangiography in left ventricular volume measurement

    International Nuclear Information System (INIS)

    Purpose: To compare the relative accuracy of left ventricular volume measured by electron-beam computed tomography (EBCT) and conventional cineangiography. Materials and methods: Fourteen human left ventricular casts underwent electron-beam computed tomography scanning and conventional biplane cineangiography. The true left ventricular volume was measured by displacement of water. EBCT left ventricular volume was calculated with modified Simpson's method, the cineangiographic left ventricular volume was calculated with biplane area-length method. Results: The actual left ventricular cast volume was 55.57 +- 28.91 ml, EBCT left ventricular volume was 66.50 +- 33.04 ml for long-axis view, and 60.36 +- 29.90 ml for short-axis view, ventricular volume from biplane cineangiography was 82.09 +- 40.40 ml. Left ventricular volume from biplane cineangiography was significantly larger than those from EBCT and the actual volume (P0.98). Conclusion: EBCT is more accurate for left ventricular volume measurement and should become the gold standard

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses What is CT (Computed Tomography) of the Sinuses? What are ...

  8. Patient dose from kilovoltage cone beam computed tomography imaging in radiation therapy

    International Nuclear Information System (INIS)

    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[reg] 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 deg.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

  9. 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. PMID:27601835

  10. 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.

  11. Electron beam diagnostic system using computed tomography and an annular sensor

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, John W.; Teruya, Alan T.

    2015-08-11

    A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

  12. Electron beam diagnostic system using computed tomography and an annular sensor

    Science.gov (United States)

    Elmer, John W.; Teruya, Alan T.

    2014-07-29

    A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

  13. Children's (Pediatric) CT (Computed Tomography)

    Science.gov (United States)

    ... Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  14. Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

    Directory of Open Access Journals (Sweden)

    Joo JH

    2016-05-01

    Full Text Available Ji Hyeon Joo, Yeon Joo Kim, Young Seok Kim, Young Pil Cho, Ho Yeon Lee, Chang Young Jeong, Jungwon Kwak, Byung Chul Cho Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Republic of Korea Background: The authors conducted this prospective study to analyze the amount of interfractional prostate bed motion (PBM and quantify its components with the use of an endorectal balloon (ERB.Methods: A total of 1,348 cone beam computed tomography images from 46 patients who underwent postprostatectomy radiotherapy were analyzed. For the pilot image, electronic portal imaging, guided by skin marks was performed to ensure proper positioning and inflation of the ERB. Then, for bone matching, manual or automatic registration of the planning and each cone beam computed tomography was performed, based on the bony anatomy of the pelvis. Shifts (bony misalignment [BM] in three directions were recorded at each treatment session. For prostate bed matching, manual matching was conducted based on the anterior rectal wall and the shift (PBM was recorded. Total setup error was defined as the shift from the skin mark to the prostate bed matching, based on anterior rectal wall stretched by the ERB. PBM was defined as the difference between the total setup error and BM.Results: Systematic errors for the total setup error were 1.0, 1.3, and 1.0 mm in the right–left, anterior–posterior, and superior–inferior directions, with random errors of 1.9, 2.4, and 1.9 mm, respectively. Systematic errors were 1.6, 1.6, and 0.3 mm for BM and 0.8, 1.1, and 0.9 mm for PBM, with random errors of 2.4, 2.5, and 1.1 mm for BM and 1.8, 2.2, and 1.9 mm for PBM.Conclusion: The BM was the main component of the total setup error, suggesting that interfractional PBM was well controlled by the ERB device. Planning target volume margins of <5 mm were needed to include 95% of the interfractional variations when using an ERB. Keywords

  15. Osteogenesis effect of guided bone regeneration combined with alveolar cleft grafting: assessment by cone beam computed tomography.

    Science.gov (United States)

    Xiao, W-L; Zhang, D-Z; Chen, X-J; Yuan, C; Xue, L-F

    2016-06-01

    Cone beam computed tomography (CBCT) allows for a significantly lower radiation dose than conventional computed tomography (CT) scans and provides accurate images of the alveolar cleft area. The osteogenic effect of guided bone regeneration (GBR) vs. conventional alveolar bone grafting alone for alveolar cleft defects was evaluated in this study. Sixty alveolar cleft patients were divided randomly into two groups. One group underwent GBR using acellular dermal matrix film combined with alveolar bone grafting using iliac crest bone grafts (GBR group), while the other group underwent alveolar bone grafting only (non-GBR group). CBCT images were obtained at 1 week and at 3 months following the procedure. Using Simplant 11.04 software, the bone resorption rate was calculated and compared between the two groups. The bone resorption rate from 1 week to 3 months following bone grafting without the GBR technique was 36.50±5.04%, whereas the bone resorption rate using the GBR technique was 31.69±5.50% (P=0.017). The application of autogenous iliac bone combined with the GBR technique for alveolar bone grafting of alveolar cleft patients can reduce bone resorption and result in better osteogenesis. PMID:26876144

  16. Development and implementation of a low-cost phantom for quality control in cone beam computed tomography.

    Science.gov (United States)

    Batista, W O; Navarro, M V T; Maia, A F

    2013-12-01

    A phantom for quality control in cone beam computed tomography (CBCT) scanners was designed and constructed, and a methodology for testing was developed. The phantom had a polymethyl methacrylate structure filled with water and plastic objects that allowed the assessment of parameters related to quality control. The phantom allowed the evaluation of essential parameters in CBCT as well as the evaluation of linear and angular dimensions. The plastics used in the phantom were chosen so that their density and linear attenuation coefficient were similar to those of human facial structures. Three types of CBCT equipment, with two different technological concepts, were evaluated. The results of the assessment of the accuracy of linear and angular dimensions agreed with the existing standards. However, other parameters such as computed tomography number accuracy, uniformity and high-contrast detail did not meet the tolerances established in current regulations or the manufacturer's specifications. The results demonstrate the importance of establishing specific protocols and phantoms, which meet the specificities of CBCT. The practicality of implementation, the quality control test results for the proposed phantom and the consistency of the results using different equipment demonstrate its adequacy. PMID:23838096

  17. Development and implementation of a low-cost phantom for quality control in cone beam computed tomography

    International Nuclear Information System (INIS)

    A phantom for quality control in cone beam computed tomography (CBCT) scanners was designed and constructed, and a methodology for testing was developed. The phantom had a polymethyl methacrylate structure filled with water and plastic objects that allowed the assessment of parameters related to quality control. The phantom allowed the evaluation of essential parameters in CBCT as well as the evaluation of linear and angular dimensions. The plastics used in the phantom were chosen so that their density and linear attenuation coefficient were similar to those of human facial structures. Three types of CBCT equipment, with two different technological concepts, were evaluated. The results of the assessment of the accuracy of linear and angular dimensions agreed with the existing standards. However, other parameters such as computed tomography number accuracy, uniformity and high-contrast detail did not meet the tolerances established in current regulations or the manufacturer's specifications. The results demonstrate the importance of establishing specific protocols and phantoms, which meet the specificities of CBCT. The practicality of implementation, the quality control test results for the proposed phantom and the consistency of the results using different equipment demonstrate its adequacy. (authors)

  18. Cardiovascular measurement and cardiac function analysis with electron beam computed tomography in health Chinese people (50 cases report)

    International Nuclear Information System (INIS)

    Purpose: To quantitatively measure cardiovascular diameters and function parameters by using electron beam computed tomography, EBCT. Methods: Men 50 health Chinese people accepted EBCT common transverse and short-axis enhanced movie scan (27 men, 23 women, average age 47.7 years.). The transverse scan was used to measure the diameters of the ascending aorta, descending aorta, pulmonary artery and left atrium. The movie study was used to measure the left ventricular myocardium thickness and analysis global, sectional and segmental function of the right and left ventricles. Results: The cardiovascular diameters and cardiac functional parameters were calculated. The diameters and most functional parameters (end syspoble volume, syspole volume, ejection fraction, cardiac-output, cardiac index) of normal Chinese men were greater than those of women (P>0.05). However, the EDV and MyM(myocardium mass) of both ventricles were significant (p<0.01). Conclusion: EBCT is a minimally invasive method for cardiovascular measurement and cardiac function evaluation

  19. Clival Lesion incidentally discovered on cone-beam computed tomography: A case report and review of the literature

    International Nuclear Information System (INIS)

    An osteolytic lesion with a small central area of mineralization and sclerotic borders was discovered incidentally in the clivus on the cone-beam computed tomography (CBCT) of a 27-year-old male patient. This benign appearance indicated a primary differential diagnosis of non-aggressive lesions such as fibro-osseous lesions and arrested pneumatization. Further, on magnetic resonance imaging (MRI), the lesion showed a homogenously low T1 signal intensity with mild internal enhancement after post-gadolinium and a heterogeneous T2 signal intensity. These signal characteristics might be attributed to the fibrous tissues, chondroid matrix, calcific material, or cystic component of the lesion; thus, chondroblastoma and chondromyxoid fibroma were added to the differential diagnosis. Although this report was limited by the lack of final diagnosis and the patient lost to follow-up, the incidental skull base finding would be important for interpreting the entire volume of CBCT by a qualified oral and maxillofacial radiologist.

  20. Cone Beam Computed Tomography Evaluation of Bone Remodeling Following the Osteotome Sinus Floor Elevation Technique for Future Site Development.

    Science.gov (United States)

    Nakajima, Kazutoshi; Kusama, Yukio

    2016-01-01

    The effectiveness of the osteotome technique for sinus augmentation was evaluated using cone beam computed tomography (CBCT) analysis. Clinical results of two-stage sinus floor elevation using the osteotome technique performed on 15 patients at the Nakajima Dental Clinic between 2006 and 2013 were evaluated retrospectively. CBCT imaging revealed that the maxillary sinus floor was elevated by an average of 7.28 mm (SD 1.62) immediately following surgery, with a mean bone height of 9.55 mm (SD 1.43). In all cases, the osteotome technique provided sufficient bone height for implant placement. No pre- or postoperative complications (eg, mucosal perforation) were reported. The minimal surgical stress and morbidity further underscore the practicality of this approach for two-stage maxillary sinus floor augmentation. PMID:27333007

  1. Endodontic Treatment of a Maxillary First Molar with Seven Root Canals Confirmed with Cone Beam Computer Tomography – Case Report

    Science.gov (United States)

    2014-01-01

    The most common configuration of the maxillary first molar is the presence of three roots and four root canals, although the presence of several other configurations have already been reported. The objective of this work is to present a rare anatomic configuration with seven root canals diagnosed during an endodontic therapy. Endodontic treatment was performed using a dental operating microscope. Exploring the grooves surrounding the main canals with ultrasonic troughing was able expose unexpected root canals. Instrumentation with files of smaller sizes and tapers was performed to prevent root physical weakness. The anatomic configuration was confirmed with a Cone Beam Computer Tomography image analysis which was able to clearly show the presence of seven root canals. An electronic database search was conducted to identify all the published similar cases and the best techniques to approach them are discussed. PMID:25121069

  2. Clival Lesion incidentally discovered on cone-beam computed tomography: A case report and review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, Aniket B.; Tadinada, Aditya; Rengasamy, Kandasamy; Lurie, Alan G. [Dept. of Oral and Maxillofacial Radiology, University of Connecticut School of Dental Medicine, Farmington (United States); Douglas, Fellows [Division of Diagnostic Sciences and Therapeutics, University of Connecticut School of Medicine, Farmington (United States)

    2014-06-15

    An osteolytic lesion with a small central area of mineralization and sclerotic borders was discovered incidentally in the clivus on the cone-beam computed tomography (CBCT) of a 27-year-old male patient. This benign appearance indicated a primary differential diagnosis of non-aggressive lesions such as fibro-osseous lesions and arrested pneumatization. Further, on magnetic resonance imaging (MRI), the lesion showed a homogenously low T1 signal intensity with mild internal enhancement after post-gadolinium and a heterogeneous T2 signal intensity. These signal characteristics might be attributed to the fibrous tissues, chondroid matrix, calcific material, or cystic component of the lesion; thus, chondroblastoma and chondromyxoid fibroma were added to the differential diagnosis. Although this report was limited by the lack of final diagnosis and the patient lost to follow-up, the incidental skull base finding would be important for interpreting the entire volume of CBCT by a qualified oral and maxillofacial radiologist.

  3. Computed Tomography (CT) -- Head

    Medline Plus

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  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Images related to Computed Tomography (CT) - Sinuses About this Site RadiologyInfo.org is produced by: Please note ... you can search the ACR-accredited facilities database . This website does not provide cost information. The costs ...

  5. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses ...

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head ...

  7. Practically acquired and modified cone-beam computed tomography images for accurate dose calculation in head and neck cancer

    International Nuclear Information System (INIS)

    On-line cone-beam computed tomography (CBCT) may be used to reconstruct the dose for geometric changes of patients and tumors during radiotherapy course. This study is to establish a practical method to modify the CBCT for accurate dose calculation in head and neck cancer. Fan-beam CT (FBCT) and Elekta's CBCT were used to acquire images. The CT numbers for different materials on CBCT were mathematically modified to match them with FBCT. Three phantoms were scanned by FBCT and CBCT for image uniformity, spatial resolution, and CT numbers, and to compare the dose distribution from orthogonal beams. A Rando phantom was scanned and planned with intensity-modulated radiation therapy (IMRT). Finally, two nasopharyngeal cancer patients treated with IMRT had their CBCT image sets calculated for dose comparison. With 360 acquisition of CBCT and high-resolution reconstruction, the uniformity of CT number distribution was improved and the otherwise large variations for background and high-density materials were reduced significantly. The dose difference between FBCT and CBCT was < 2% in phantoms. In the Rando phantom and the patients, the dose-volume histograms were similar. The corresponding isodose curves covering ≥ 90% of prescribed dose on FBCT and CBCT were close to each other (within 2 mm). Most dosimetric differences were from the setup errors related to the interval changes in body shape and tumor response. The specific CBCT acquisition, reconstruction, and CT number modification can generate accurate dose calculation for the potential use in adaptive radiotherapy.

  8. Tilting the jaw to improve the image quality or to reduce the dose in cone-beam computed tomography

    International Nuclear Information System (INIS)

    Objective: The image quality in cone-beam computed tomography (CBCT) should be improved tilting the mandible that contains two dental titanium implants, within the relevant range of motion. Materials and methods: Using the mandible of a five-month-old pig, CBCT was performed varying the accelerating voltage, beam current, the starting rotation angle of the mandible in the source-detector plane and the tilt angles of the jaw with respect to the source-detector plane. The different datasets were automatically registered with respect to micro CT data to extract the common volume and the deviance to the pre-defined standard that characterizes the image quality. Results: The variations of the accelerating voltage, beam current and the rotation within the source-detection plane provided the expected quantitative behavior indicating the appropriate choice of the imaging quality factor. The tilting of the porcine mandible by about 14° improves the image quality by almost a factor of two. Conclusions: The tilting of the mandible with two dental implants can be used to significantly reduce the artifacts of the strongly X-ray absorbing materials in the CBCT images. The comparison of 14° jaw tilting with respect to the currently recommended arrangement in plane with the teeth demonstrates that the applied exposure time and the related dose can be reduced by a factor of four without decreasing the image quality.

  9. Practically acquired and modified cone-beam computed tomography images for accurate dose calculation in head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chih-Chung [National Taiwan Univ. Hospital and College of Medicine, Taipei (China). Division of Radiation Oncology; Yuanpei Univ., Hsinchu (China). Dept. of Radiological Technology; Huang, Wen-Tao [Yuanpei Univ., Hsinchu (China). Dept. of Radiological Technology; Tsai, Chiao-Ling; Chao, Hsiao-Ling; Huang, Guo-Ming; Wang, Chun-Wei [National Taiwan Univ. Hospital and College of Medicine, Taipei (China). Division of Radiation Oncology; Wu, Jian-Kuen [National Taiwan Univ. Hospital and College of Medicine, Taipei (China). Division of Radiation Oncology; National Taiwan Normal Univ., Taipei (China). Inst. of Electro-Optical Science and Technology; Wu, Chien-Jang [National Taiwan Normal Univ., Taipei (China). Inst. of Electro-Optical Science and Technology; Cheng, Jason Chia-Hsien [National Taiwan Univ. Hospital and College of Medicine, Taipei (China). Division of Radiation Oncology; National Taiwan Univ. Taipei (China). Graduate Inst. of Oncology; National Taiwan Univ. Taipei (China). Graduate Inst. of Clinical Medicine; National Taiwan Univ. Taipei (China). Graduate Inst. of Biomedical Electronics and Bioinformatics

    2011-10-15

    On-line cone-beam computed tomography (CBCT) may be used to reconstruct the dose for geometric changes of patients and tumors during radiotherapy course. This study is to establish a practical method to modify the CBCT for accurate dose calculation in head and neck cancer. Fan-beam CT (FBCT) and Elekta's CBCT were used to acquire images. The CT numbers for different materials on CBCT were mathematically modified to match them with FBCT. Three phantoms were scanned by FBCT and CBCT for image uniformity, spatial resolution, and CT numbers, and to compare the dose distribution from orthogonal beams. A Rando phantom was scanned and planned with intensity-modulated radiation therapy (IMRT). Finally, two nasopharyngeal cancer patients treated with IMRT had their CBCT image sets calculated for dose comparison. With 360 acquisition of CBCT and high-resolution reconstruction, the uniformity of CT number distribution was improved and the otherwise large variations for background and high-density materials were reduced significantly. The dose difference between FBCT and CBCT was < 2% in phantoms. In the Rando phantom and the patients, the dose-volume histograms were similar. The corresponding isodose curves covering {>=} 90% of prescribed dose on FBCT and CBCT were close to each other (within 2 mm). Most dosimetric differences were from the setup errors related to the interval changes in body shape and tumor response. The specific CBCT acquisition, reconstruction, and CT number modification can generate accurate dose calculation for the potential use in adaptive radiotherapy.

  10. Effect of time lapse on the diagnostic accuracy of cone beam computed tomography for detection of vertical root fractures

    Energy Technology Data Exchange (ETDEWEB)

    Eskandarloo, Amir; Shokri, Abbas, E-mail: Dr.a.shokri@gmail.com [Dental Research Center, Department of Oral and Maxillofacial Radiology, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Asl, Amin Mahdavi [Department of Oral and Maxillofacial Radiology, Golestan University of Medical Sciences, Gorgan (Iran, Islamic Republic of); Jalalzadeh, Mohsen [Department of Endodontics, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Tayari, Maryam [Department of Pedodontics, Golestan University of Medical Sciences, Gorgan (Iran, Islamic Republic of); Hosseinipanah, Mohammad [Department of Anatomy, School of Medicine, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Fardmal, Javad [Research Center for Health Sciences and Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of)

    2016-01-15

    Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog’s teeth. Forty eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans. (author)

  11. Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table

    International Nuclear Information System (INIS)

    Purpose: To scrutinize the positioning accuracy and reproducibility of a commercial hexapod robot treatment table (HRTT) in combination with a commercial cone-beam computed tomography system for image-guided radiotherapy (IGRT). Methods and Materials: The mechanical stability of the X-ray volume imaging (XVI) system was tested in terms of reproducibility and with a focus on the moveable parts, i.e., the influence of kV panel and the source arm on the reproducibility and accuracy of both bone and gray value registration using a head-and-neck phantom. In consecutive measurements the accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated. The operational range of the HRTT was also determined and analyzed. Results: The system performance of the XVI system alone was very stable with mean translational and rotational errors of below 0.2 mm and below 0.2o, respectively. The mean positioning accuracy of the HRTT in combination with the XVI system summarized over all measurements was below 0.3 mm and below 0.3o for translational and rotational corrections, respectively. The gray value match was more accurate than the bone match. Conclusion: The XVI image acquisition and registration procedure were highly reproducible. Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement cone-beam computed tomography to take full advantage of position correction in six degrees of freedom for IGRT. The combination of XVI and the HRTT has the potential to improve the accuracy of high-precision treatments

  12. Evaluation of cortical bone thickness of mandible with cone beam computed tomography for orthodontic mini implant installation

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Moslemzade

    2014-07-01

    Full Text Available Background: Achieving maximum anchorage without movement of the teeth in anchorage unit has been a great challenge in orthodontics and the success of the treatment plan highly depends on it. In this case, using orthodontic mini-implants can make a huge difference. The objective of this retrospective study was to measure thickness of cortical bone at prospective mini-implant placement sites in mandible in order to understand stability aspects of mini-implant placement by using cone-beam computed tomography (CBCT images.Materials and Methods: Initial 3-dimensional images of 40 adult patients were studied. The cortical bone thickness was obtained at the alveolar processes from canine to second molar at 5 different vertical levels from the cementoenamel junction (CEJ. To determine the cortical bone thickness, tangent lines were drawn buccolingually to the roots in axial section and a third line was drawn from the middle of these two lines, and the cortical bone thickness was measured where the third line crossed the buccal cortex. Results: Mandibular and buccal cortical bone thicknesses were 0.79 to 2.49 mm, respectively. There was a statistically significant increase from the CEJ to the apex (P<0.001, while this increase was not statically significant at interdental area of teeth #3 and #4. Comparing the 4 mm section in all sites showed significant increase from anterior to posterior.Conclusion: Based on our results, the cortical bone thickness mostly follows a pattern and depends on the interradicular site rather than individual differences.  Key words: Cone-beam computed tomography; orthodontic anchorage procedures

  13. Effect of time lapse on the diagnostic accuracy of cone beam computed tomography for detection of vertical root fractures

    International Nuclear Information System (INIS)

    Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog’s teeth. Forty eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans. (author)

  14. Validity, reliability, and reproducibility of linear measurements on digital models obtained from intraoral and cone-beam computed tomography scans of alginate impressions

    NARCIS (Netherlands)

    Wiranto, Matthew G.; Engelbrecht, W. Petrie; Nolthenius, Heleen E. Tutein; van der Meer, W. Joerd; Ren, Yijin

    2013-01-01

    INTRODUCTION: Digital 3-dimensional models are widely used for orthodontic diagnosis. The aim of this study was to assess the validity, reliability, and reproducibility of digital models obtained from the Lava Chairside Oral scanner (3M ESPE, Seefeld, Germany) and cone-beam computed tomography scans

  15. Locoregional control of non-small cell lung cancer in relation to automated early assessment of tumor regression on cone beam computed tomography

    DEFF Research Database (Denmark)

    Brink, Carsten; Bernchou, Uffe; Bertelsen, Anders;

    2014-01-01

    PURPOSE: Large interindividual variations in volume regression of non-small cell lung cancer (NSCLC) are observable on standard cone beam computed tomography (CBCT) during fractionated radiation therapy. Here, a method for automated assessment of tumor volume regression is presented and its poten...

  16. A Novel Region-Growing Based Semi-Automatic Segmentation Protocol for Three-Dimensional Condylar Reconstruction Using Cone Beam Computed Tomography (CBCT)

    NARCIS (Netherlands)

    Xi, Tong; Schreurs, Ruud; Heerink, Wout J.; Berge, Stefaan J.; Maal, Thomas J. J.

    2014-01-01

    Objective: To present and validate a semi-automatic segmentation protocol to enable an accurate 3D reconstruction of the mandibular condyles using cone beam computed tomography (CBCT). Materials and Methods: Approval from the regional medical ethics review board was obtained for this study. Bilatera

  17. Influence of object location in cone beam computed tomography (NewTom 5G and 3D Accuitomo 170) on gray value measurements at an implant site

    NARCIS (Netherlands)

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

    2014-01-01

    Objectives The aim of this study was to determine the gray value variation at an implant site with different object location within the selected field of view (FOV) in two cone beam computed tomography (CBCT) scanners. Methods A 1-cm-thick section from the edentulous region of a dry human mandible w

  18. Position of the impacted third molar in relation to the mandibular canal. Diagnostic accuracy of cone beam computed tomography compared with panoramic radiography.

    NARCIS (Netherlands)

    Ghaeminia, H.; Meijer, G.J.; Soehardi, A.; Borstlap, W.A.; Mulder, J.; Berge, S.J.

    2009-01-01

    This study investigated the diagnostic accuracy of cone beam computed tomography (CBCT) compared to panoramic radiography in determining the anatomical position of the impacted third molar in relation with the mandibular canal. The study sample comprised 53 third molars from 40 patients with an incr

  19. Maxillary sinus pneumatization after maxillary molar extraction assessed with cone beam computed tomography

    International Nuclear Information System (INIS)

    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.

  20. Empirical cupping correction: A first-order raw data precorrection for cone-beam computed tomography

    International Nuclear Information System (INIS)

    We propose an empirical cupping correction (ECC) algorithm to correct for CT cupping artifacts that are induced by nonlinearities in the projection data. The method is raw data based, empirical, and requires neither knowledge of the x-ray spectrum nor of the attenuation coefficients. It aims at linearizing the attenuation data using a precorrection function of polynomial form. The coefficients of the polynomial are determined once using a calibration scan of a homogeneous phantom. Computing the coefficients is done in image domain by fitting a series of basis images to a template image. The template image is obtained directly from the uncorrected phantom image and no assumptions on the phantom size or of its positioning are made. Raw data are precorrected by passing them through the once-determined polynomial. As an example we demonstrate how ECC can be used to perform water precorrection for an in vivo micro-CT scanner (TomoScope 30 s, VAMP GmbH, Erlangen, Germany). For this particular case, practical considerations regarding the definition of the template image are given. ECC strives to remove the cupping artifacts and to obtain well-calibrated CT values. Although ECC is a first-order correction and cannot compete with iterative higher-order beam hardening or scatter correction algorithms, our in vivo mouse images show a significant reduction of bone-induced artifacts as well. A combination of ECC with analytical techniques yielding a hybrid cupping correction method is possible and allows for channel-dependent correction functions

  1. Comparison of the radiation dose from cone beam computed tomography and multidetector computed tomography in examinations of the hand; Vergleich der Strahlendosis von Cone-Beam Computertomografie und Multidetektor Computertomografie in Untersuchungen der Hand

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, J.; Neubauer, C.; Gerstmair, A.; Krauss, T.; Kotter, E.; Langer, M. [University Medical Center Freiburg (Germany). Dept. of Radiology; Reising, K. [University Medical Center Freiburg (Germany). Dept. of Orthopedics and Trauma Surgery; Zajonc, H. [University Medical Center Freiburg (Germany). Dept. of Plastic and Hand Surgery; Fiebich, M.; Voigt, J. [University of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection

    2016-05-15

    Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand. Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures < 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose. The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT. Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization.

  2. A rare case of dilated invaginated odontome with talon cusp in a permanent maxillary central incisor diagnosed by cone beam computed tomography

    International Nuclear Information System (INIS)

    It has been a challenge to establish the accurate diagnosis of developmental tooth anomalies based on periapical radiographs. Recently, three-dimensional imaging by cone beam computed tomography has provided useful information to investigate the complex anatomy of and establish the proper management for tooth anomalies. The most severe variant of dens invaginatus, known as dilated odontome, is a rare occurrence, and the cone beam computed tomographic findings of this anomaly have never been reported for an erupted permanent maxillary central incisor. The occurrence of talon cusp occurring along with dens invaginatus is also unusual. The aim of this report was to show the importance of cone beam computed tomography in contributing to the accurate diagnosis and evaluation of the complex anatomy of this rare anomaly.

  3. A rare case of dilated invaginated odontome with talon cusp in a permanent maxillary central incisor diagnosed by cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jaya, Ranganathan; Kumar, Rangarajan Sundaresan Mohan; Srinivasan, Ramasamy [Dept. of Conservative Dentistry and Endodontics, Priyadarshini Dental College and Hospital, Chennai (India)

    2013-09-15

    It has been a challenge to establish the accurate diagnosis of developmental tooth anomalies based on periapical radiographs. Recently, three-dimensional imaging by cone beam computed tomography has provided useful information to investigate the complex anatomy of and establish the proper management for tooth anomalies. The most severe variant of dens invaginatus, known as dilated odontome, is a rare occurrence, and the cone beam computed tomographic findings of this anomaly have never been reported for an erupted permanent maxillary central incisor. The occurrence of talon cusp occurring along with dens invaginatus is also unusual. The aim of this report was to show the importance of cone beam computed tomography in contributing to the accurate diagnosis and evaluation of the complex anatomy of this rare anomaly.

  4. A Standardized Protocol for Cone-Beam Computed Tomography of the Hand and Wrist in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    D.V. Makarova

    2015-12-01

    Full Text Available The aim of the investigation was to develop a standardized protocol for description of the results of cone-beam computed tomography (CBCT of the hand and wrist in rheumatoid arthritis. Materials and Methods. The results of 112 hand and wrist CBCT examinations (n=56 were analyzed in patients aged from 36 to 67 with medium-active seropositive rheumatoid arthritis in anamnesis. The hand and wrist CBCT was carried out using a NewTom 5G cone-beam computed unit (QR s.r.l., Italy having a 200×250 mm flat-panel detector, 180×160 mm field of view (maximum, and a 360° gantry rotation around the region of interest. The hand and wrist scanning was carried out from the distal metaphysis of the forearm bones to the nail ends of the distal phalanges of the fingers. Scan mode — patient scan (exposure time — 3.6 s, X-ray tube boosting voltage — 110 kW, current — 0.6‒0.8 mA, scan pattern — regular scan, scan time — 18 s. The CBCT examinations of the wrists and hands were performed using special-purpose setups allowing complete coverage of the region of interest. Results. A standardized protocol was designed for the description of hand and wrist cone-beam examination that documents all the major changes resulting from rheumatoid arthritis: soft tissue thickening, erosions and cystic-like changes, osteoporosis, narrowing of the joint spaces, incomplete dislocations, bone deformities and areas of osteolysis. Significant changes are recorded in point form, according to the Sharp or SENS methods. Application of the standardized protocol allows unification of the structuring of the examination description, and facilitates X-ray assessment of changes in the hand and wrist during CBCT in patients with rheumatoid arthritis.

  5. Cervical computed tomography

    International Nuclear Information System (INIS)

    This book describes the possibilities of cervical computed tomography with the apparatus available at present. The normal anatomy of the cervical region as it appears in computed tomography is described with special regard to its compartimental structure and functional aspects; this is supplemented by anatomically normal measures obtained from cervical computed tomograms of 60 healthy individuals of different age and both sexes. The morphology of cervical anomalies obtained via CT and of the various acquired cervical disease processes is discussed and illustrated by means of the authors' own observations; the diagnostic value of the findings obtained by CT is discussed, a diagnosis is set up. (orig./MG)

  6. The effects of field-of-view and patient size on CT numbers from cone-beam computed tomography

    Science.gov (United States)

    Seet, Katrina Y. T.; Barghi, Arvand; Yartsev, Slav; Van Dyk, Jake

    2009-10-01

    Cone-beam computed tomography (CBCT) is used for patient alignment before treatment and is ideal for use in adaptive radiotherapy to account for tumor shrinkage, organ deformation and weight loss. However, CBCT images are prone to artifacts such as streaking and cupping effects, reducing image quality and CT number accuracy. Our goal was to determine the optimum combination of cone-beam imaging options to increase the accuracy of image CT numbers. Several phantoms with and without inserts of known relative electron densities were imaged using the Varian on-board imaging system. It was found that CT numbers are most influenced by the selection of field-of-view and are dependent on object size and filter type. Image acquisition in half-fan mode consistently produced more accurate CT numbers, regardless of phantom size. Values measured using full-fan mode can differ by up to 7% from planning CT values. No differences were found between CT numbers of all phantom images with low and standard dose modes.

  7. The effects of field-of-view and patient size on CT numbers from cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Seet, Katrina Y T; Barghi, Arvand; Yartsev, Slav; Van Dyk, Jake [London Regional Cancer Program, London Health Sciences Centre, London, Ontario (Canada)], E-mail: slav.yartsev@lhsc.on.ca

    2009-10-21

    Cone-beam computed tomography (CBCT) is used for patient alignment before treatment and is ideal for use in adaptive radiotherapy to account for tumor shrinkage, organ deformation and weight loss. However, CBCT images are prone to artifacts such as streaking and cupping effects, reducing image quality and CT number accuracy. Our goal was to determine the optimum combination of cone-beam imaging options to increase the accuracy of image CT numbers. Several phantoms with and without inserts of known relative electron densities were imaged using the Varian on-board imaging system. It was found that CT numbers are most influenced by the selection of field-of-view and are dependent on object size and filter type. Image acquisition in half-fan mode consistently produced more accurate CT numbers, regardless of phantom size. Values measured using full-fan mode can differ by up to 7% from planning CT values. No differences were found between CT numbers of all phantom images with low and standard dose modes.

  8. Computed tomography apparatus

    International Nuclear Information System (INIS)

    In fan-beam computed tomography apparatus, timing reference pulses, normally occurring at intervals t, for data transfer and reset of approx. 500 integrators in the signal path from the detector array, are generated from the scan displacement, e.g. using a graticule and optical sensor to relate the measurement paths geometrically to the body section. Sometimes, a slow scan rate is required to provide a time-averaged density image, e.g. for planning irradiation therapy, and then the sensed impulses will occur at extended intervals and can cause integrator overload. An improvement is described which provides a pulse generator which responds to a reduced scan rate by generating a succession of further transfer and reset pulses at intervals approximately equal to t starting a time t after each timing reference pulse. Then, using an adding device and RAM, all the transferred signals integrated in the interval t' between two successive slow scan reference pulses are accumulated in order to form a corresponding measurement signal. (author)

  9. Observation of positional relation between mandibular third molars and the mandibular canal on limited cone beam computed tomography

    International Nuclear Information System (INIS)

    We describe the preoperative use of limited cone beam computed tomography (CT) with a dental CT scanner for the assessment of mandibular third molars before extraction. Cone beam CT provides 42.7-mm-high and 30-mm-wide rectangular solid images, with a resolution of less than 0.2 mm. The positional relationship between the mandibular third molars and the mandibular canal was examined by dental CT. Sixty-eight lower third molars of 62 patients whose teeth were superimposed on the mandibular canal on periapical or panoramic radiographs were studied. Dental CT scans clearly demonstrated the positional relationship between the mandibular canal and the teeth. The mandibular canal was located buccally to the roots of 16 teeth, lingually to the roots of 27 teeth, inferiorly to the roots of 23 teeth, and between the roots of 2 teeth. The presence of bone between the mandibular canal and the teeth was not noted in 7 of 16 buccal cases, 24 of 27 lingual cases, and 10 of 23 inferior cases on dental CT scans, suggesting that the canal was in contact with the teeth. Fifty-nine of the 68 mandibular third molars were surgically removed, and postoperative transient hypoesthesia occurred in 4 patients. Dental CT scans showed no bone between the mandibular canal and the teeth in all 4 patients. Hypoesthesia was not related to the bucco-lingual location of the mandibular canal or to the extent of bone loss between the canal and the teeth. However, hypoesthesia did not occur in patients with bone between the mandibular canal and the teeth. Thus, information on the distance between the canal and teeth on dental CT scans was useful for predicting the risk of inferior alveolar nerve damage. Because of its high resolution and low radiation dose, cone beam CT was useful for examination before mandibular third molar surgery. (author)

  10. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore

  11. Organ doses can be estimated from the computed tomography (CT) dose index for cone-beam CT on radiotherapy equipment.

    Science.gov (United States)

    Martin, Colin J; Abuhaimed, Abdullah; Sankaralingam, Marimuthu; Metwaly, Mohamed; Gentle, David J

    2016-06-01

    Cone beam computed tomography (CBCT) systems are fitted to radiotherapy linear accelerators and used for patient positioning prior to treatment by image guided radiotherapy (IGRT). Radiotherapists' and radiographers' knowledge of doses to organs from CBCT imaging is limited. The weighted CT dose index for a reference beam of width 20 mm (CTDIw,ref) is displayed on Varian CBCT imaging equipment known as an On-Board Imager (OBI) linked to the Truebeam linear accelerator. This has the potential to provide an indication of organ doses. This knowledge would be helpful for guidance of radiotherapy clinicians preparing treatments. Monte Carlo simulations of imaging protocols for head, thorax and pelvic scans have been performed using EGSnrc/BEAMnrc, EGSnrc/DOSXYZnrc, and ICRP reference computational male and female phantoms to derive the mean absorbed doses to organs and tissues, which have been compared with values for the CTDIw,ref displayed on the CBCT scanner console. Substantial variations in dose were observed between male and female phantoms. Nevertheless, the CTDIw,ref gave doses within  ±21% for the stomach and liver in thorax scans and 2  ×  CTDIw,ref can be used as a measure of doses to breast, lung and oesophagus. The CTDIw,ref could provide indications of doses to the brain for head scans, and the colon for pelvic scans. It is proposed that knowledge of the link between CTDIw for CBCT should be promoted and included in the training of radiotherapy staff. PMID:26975735

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

    NARCIS (Netherlands)

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

    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

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head What is CT Scanning of the Head? What are some ...

  14. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography ( ... used in your exam. You should inform your physician of all medications you are taking and if ...

  15. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography ( ... used in your exam. You should inform your physician of all medications you are taking and if ...

  16. Chest computed tomography

    DEFF Research Database (Denmark)

    Loeve, Martine; Krestin, Gabriel P.; Rosenfeld, Margaret;

    2013-01-01

    are not suitable to study CF lung disease in young children. Chest computed tomography (CT) holds great promise for use as a sensitive surrogate endpoint in CF. A large body of evidence has been produced to validate the use of chest CT as primary endpoint to study CF lung disease. However, before...

  17. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head ... CT exam to be stressful. The technologist or nurse, under the direction of a physician, may offer ...

  18. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses ... visibility of certain tissues or blood vessels. A nurse or technologist will insert an intravenous (IV) line ...

  19. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  1. Prediction of beam hardening artefacts in computed tomography using Monte Carlo simulations

    Science.gov (United States)

    Thomsen, M.; Knudsen, E. B.; Willendrup, P. K.; Bech, M.; Willner, M.; Pfeiffer, F.; Poulsen, M.; Lefmann, K.; Feidenhans'l, R.

    2015-01-01

    We show how radiological images of both single and multi material samples can be simulated using the Monte Carlo simulation tool McXtrace and how these images can be used to make a three dimensional reconstruction. Good numerical agreement between the X-ray attenuation coefficient in experimental and simulated data can be obtained, which allows us to use simulated projections in the linearisation procedure for single material samples and in that way reduce beam hardening artefacts. The simulations can be used to predict beam hardening artefacts in multi material samples with complex geometry, illustrated with an example. Linearisation requires knowledge about the X-ray transmission at varying sample thickness, but in some cases homogeneous calibration phantoms are hard to manufacture, which affects the accuracy of the calibration. Using simulated data overcomes the manufacturing problems and in that way improves the calibration.

  2. Prediction of beam hardening artefacts in computed tomography using Monte Carlo simulations

    International Nuclear Information System (INIS)

    We show how radiological images of both single and multi material samples can be simulated using the Monte Carlo simulation tool McXtrace and how these images can be used to make a three dimensional reconstruction. Good numerical agreement between the X-ray attenuation coefficient in experimental and simulated data can be obtained, which allows us to use simulated projections in the linearisation procedure for single material samples and in that way reduce beam hardening artefacts. The simulations can be used to predict beam hardening artefacts in multi material samples with complex geometry, illustrated with an example. Linearisation requires knowledge about the X-ray transmission at varying sample thickness, but in some cases homogeneous calibration phantoms are hard to manufacture, which affects the accuracy of the calibration. Using simulated data overcomes the manufacturing problems and in that way improves the calibration

  3. Cone beam optical computed tomography for gel dosimetry I: scanner characterization

    Energy Technology Data Exchange (ETDEWEB)

    Olding, Tim; Holmes, Oliver; Schreiner, L John, E-mail: tim.olding@krcc.on.c [Department of Physics, Queen' s University, Kingston, ON, K7L 3N6 (Canada)

    2010-05-21

    The ongoing development of easily accessible, fast optical readout tools promises to remove one of the barriers to acceptance of gel dosimetry as a viable tool in cancer clinics. This paper describes the characterization of a number of basic properties of the Vista(TM) cone beam CCD-based optical scanner, which can obtain high resolution reconstructed data in less than 20 min total imaging and reconstruction time. The suitability of a filtered back projection cone beam reconstruction algorithm is established for optically absorbing dosimeters using this scanner configuration. The system was then shown to be capable of imaging an optically absorbing media-filled 1 L polyethylene terephthalate (PETE) jar dosimeter to a reconstructed voxel resolution of 0.5 x 0.5 x 0.5 mm{sup 3}. At this resolution, more than 60% of the imaged volume in the dosimeter exhibits minimal spatial distortion, a measurement accuracy of 3-4% and the mean to standard deviation signal-to-noise ratio greater than 100 over an optical absorption range of 0.06-0.18 cm{sup -1}. An inter-day scan precision of 1% was demonstrated near the upper end of this range. Absorption measurements show evidence of stray light perturbation causing artifacts in the data, which if better managed would improve the accuracy of optical readout. Cone beam optical attenuation measurements of scattering dosimeters, on the other hand, are nonlinearly affected by angled scatter stray light. Scatter perturbation leads to significant cupping artifacts and other inaccuracies that greatly limit the readout of scattering polymer gel dosimeters with cone beam optical CT.

  4. Beam hardening correction for X-ray computed tomography of heterogeneous natural materials

    Science.gov (United States)

    Ketcham, Richard A.; Hanna, Romy D.

    2014-06-01

    We present a new method for correcting beam hardening artifacts in polychromatic X-ray CT data. On most industrial CT systems, software beam-hardening correction employs some variety of linearization, which attempts to transform the polychromatic attenuation data into its monochromatic equivalent prior to image reconstruction. However, determining optimal coefficients for the transform equation is not straightforward, especially if the material is not well known or characterized, as is the usual case when imaging geological materials. Our method uses an iterative optimization algorithm to find a generalized spline-interpolated transform that minimizes artifacts as defined by an expert user. This generality accesses a richer set of linearization functions that may better accommodate the effects of multiple materials in heterogeneous samples. When multiple materials are present in the scan field, there is no single optimal correction, and the solution can vary depending on which aspects of the beam-hardening and other image artifacts the user wants to minimize. For example, the correction can be optimized to maximize the fidelity of the object outline for solid model creation rather than simply to minimize variation of CT numbers within the material. We demonstrate our method on a range of specimens of varying difficulty and complexity, with consistently positive results.

  5. Cone-Beam Computed Tomography Assessment of Root Canal Transportation by Neoniti and Reciproc Single-File Systems

    Science.gov (United States)

    Moazzami, Fariborz; Khojastepour, Leila; Nabavizadeh, Mohammadreza; Seied Habashi, Mina

    2016-01-01

    Introduction: The aim of this in vitro study was to compare the canal transportation of two single-file engine-driven systems, Neoniti and Reciproc, using cone-beam computed tomography (CBCT). Methods and Materials: Forty-five non-calcified roots with mature apices and apical curvature of 15-30 degrees were selected from extracted human maxillary molars for this study. Samples were randomly divided into two groups (n=20) and a control group (n=5) and canal preparation with either system was performed according to manufacturers' instructions. Pre- and post-instrumentation CBCT images were captured and the amount of canal transportation within the files was calculated at levels of 3, 4, and 5 mm from the apex. The independent sample t-test was used to analyze the statistical significance between the two groups. The level of significance was defined at 0.05. Results: Reciproc created more canal transportation compared to Neoniti in both mesiodistal and buccolingual directions. The difference between the two systems was statistically significant in all evaluated distances from the apex (PReciproc systems have significant difference in terms of creating canal transportation. Reciproc created more canal transportation in buccolingual and mesiodistal dimensions. PMID:27141215

  6. Feasibility Study of Needle Placement in Percutaneous Vertebroplasty: Cone-Beam Computed Tomography Guidance Versus Conventional Fluoroscopy

    International Nuclear Information System (INIS)

    ObjectiveTo investigate the accuracy, procedure time, fluoroscopy time, and dose area product (DAP) of needle placement during percutaneous vertebroplasty (PVP) using cone-beam computed tomography (CBCT) guidance versus fluoroscopy.Materials and MethodsOn 4 spine phantoms with 11 vertebrae (Th7–L5), 4 interventional radiologists (2 experienced with CBCT guidance and two inexperienced) punctured all vertebrae in a bipedicular fashion. Each side was randomization to either CBCT guidance or fluoroscopy. CBCT guidance is a sophisticated needle guidance technique using CBCT, navigation software, and real-time fluoroscopy. The placement of the needle had to be to a specific target point. After the procedure, CBCT was performed to determine the accuracy, procedure time, fluoroscopy time, and DAP. Analysis of the difference between methods and experience level was performed.ResultsMean accuracy using CBCT guidance (2.61 mm) was significantly better compared with fluoroscopy (5.86 mm) (p 2, respectively (p < 0.0001). There was a significant difference in favor of experienced CBCT guidance users regarding accuracy for both methods, procedure time of CBCT guidance, and added DAP values for fluoroscopy.ConclusionCBCT guidance allows users to perform PVP more accurately at the cost of higher patient dose and longer procedure time. Because procedural complications (e.g., cement leakage) are related to the accuracy of the needle placement, improvements in accuracy are clinically relevant. Training in CBCT guidance is essential to achieve greater accuracy and decrease procedure time/dose values

  7. Accuracy and speed of robotic assisted needle interventions using a modern cone beam computed tomography intervention suite: a phantom study

    International Nuclear Information System (INIS)

    To analyse the feasibility and accuracy of robotic aided interventions on a phantom when using a modern C-arm-mounted cone beam computed tomography (CBCT) device in combination with needle guidance software. A small robotic device capable of holding and guiding needles was attached to the intervention table. After acquiring a 3D data set the access path was planned on the CBCT workstation and shown on the intervention monitor. Then the robot was aligned to the live fluoroscopic image. A total of 40 punctures were randomly conducted on a phantom armed with several targets (diameter 2 mm) in single and double oblique trajectory (n = 20 each). Target distance, needle deviation and time for the procedures were analysed. All phantom interventions (n = 40) could be performed successfully. Mean target access path within the phantom was 8.5 cm (min 4.2 cm, max 13.5 cm). Average needle tip deviation was 1.1 mm (min 0 mm, max 4.5 mm), time duration was 3:59 min (min 2:07 min, max 10:37 min). When using the proposed robot device in a CBCT intervention suite, highly accurate needle-based interventional punctures are possible in a reasonable timely manner in single as well as in double oblique trajectories. (orig.)

  8. Diagnostic performance of cone-beam computed tomography on detection of mechanically-created artificial secondary caries

    International Nuclear Information System (INIS)

    The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve (Az) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). The mean Az values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest Az value. Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

  9. Comparison of Cone-Beam Computed Tomography and Periapical Radiography in Predicting Treatment Decision for Periapical Lesions: A Clinical Study

    Directory of Open Access Journals (Sweden)

    Ashok Balasundaram

    2012-01-01

    Full Text Available Objectives. To compare the ability of endodontists to determine the size of apical pathological lesions and select the most appropriate choice of treatment based on lesions’ projected image characteristics using 2 D and 3 D images. Study Design. Twenty-four subjects were selected. Radiographic examination of symptomatic study teeth with an intraoral periapical radiograph revealed periapical lesions equal to or greater than 3 mm in the greatest diameter. Cone-beam Computed tomography (CBCT images were made of the involved teeth after the intraoral periapical radiograph confirmed the size of lesion to be equal to greater than 3 mm. Six observers (endodontists viewed both the periapical and CBCT images. Upon viewing each of the images from the two imaging modalities, observers (1 measured lesion size and (2 made decisions on treatment based on each radiograph. Chi-square test was used to look for differences in the choice of treatment among observers. Results. No significant difference was noted in the treatment plan selected by observers using the two modalities (χ2(3=.036, P>0.05. Conclusion. Lesion size and choice of treatment of periapical lesions based on CBCT radiographs do not change significantly from those made on the basis of 2 D radiographs.

  10. The effect of voxel size on the measurement of mandibular thickness in cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Ehsan Hekmatian

    2014-01-01

    Full Text Available Background: Cone-beam computed tomography (CBCT is a new imaging technology that has been widely used in implantology, oral and maxillofacial surgery and orthodontics. This method provides 3-D images that are composed of voxel, which is the smallest image unit, and determines image resolution. Smaller voxel is associated with the higher resolution and also greater radiation exposure. This study was aimed to find out the effect of voxel size on the measurement of mandibular thickness. Materials and Methods: Using voxel sizes of 0.30 mm and 0.15 mm, two CBCT protocols (protocol 1: Field of view (FOV of 15 cm, 85 kVp, 42 mAs, 0.15 mm voxel, 14 s scan time; protocol 2: FOV of 15 cm, 85 kVp, 10 mAs, 0.30 mm voxel, 14 s scan time were carried out on 16 dry human mandibles with permanent dentition. Mandibular thickness was measured at seven different sites (midline region, bilateral canine regions, bilateral mental foramen regions and bilateral molar regions. Analysis of variance was used for analysis of data using the Statistical Package for the Social Sciences version 20 (SPSS Inc., Chicago, IL, USA. P 0.05. Conclusion: Considering the insignificant differences of the mandibular thickness measurements using different voxel sizes, it would be more reasonable to use 0.30 mm voxel size instead of 0.15 mm voxel size to avoid unnecessary radiation exposure.

  11. Cone-beam computed tomography study of root and canal morphology of mandibular premolars in a western Chinese population

    International Nuclear Information System (INIS)

    Traditional radiography is limited in its ability to give reliable information on the number and morphology of root canals. The application of cone-beam computed tomography (CBCT) provides a non-invasive three-dimensional confirmatory diagnosis as a complement to conventional radiography. The aim of this study was to evaluate the root and canal morphology of mandibular premolars in a western Chinese population using CBCT scanning. The sample included 149 CBCT images comprising 178 mandibular first premolars and 178 second premolars. The tooth position, number of roots and canals, and canal configuration according to Vertucci’s classification were recorded. The results showed that 98% of mandibular first premolars had one root and 2% had two roots; 87.1% had one canal, 11.2% had two canals and 0.6% had three canals. The prevalence of C-shaped canals was 1.1%. All mandibular second premolars had one root; 97.2% had one canal and 2.2% had two canals. The prevalence of C-shaped canals was 0.6%. The prevalence of multiple canals in mandibular first premolars was mainly of Type V, and mandibular second premolars had a low rate of canal variation in this western Chinese population. Root canal bifurcation occurred at the middle or apical third in most bicanal mandibular premolars. CBCT scanning can be used in the management of mandibular premolars with complex canal morphology

  12. Correlation between hyoid bone position and airway dimensions in Chinese adolescents by cone beam computed tomography analysis.

    Science.gov (United States)

    Jiang, Y-Y

    2016-07-01

    This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery. PMID:26949129

  13. Accuracy and speed of robotic assisted needle interventions using a modern cone beam computed tomography intervention suite: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Boris [Goethe University Hospital, Institute for Diagnostic and Interventional Radiology, Frankfurt (Germany); Goethe University Hospital, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Eichler, Katrin; Siebenhandl, Petra; Gruber-Rouh, Tatjana; Vogl, Thomas Josef; Zangos, Stephan [Goethe University Hospital, Institute for Diagnostic and Interventional Radiology, Frankfurt (Germany); Czerny, Christoph [Goethe University Hospital, Department of Trauma Surgery, Frankfurt (Germany)

    2013-01-15

    To analyse the feasibility and accuracy of robotic aided interventions on a phantom when using a modern C-arm-mounted cone beam computed tomography (CBCT) device in combination with needle guidance software. A small robotic device capable of holding and guiding needles was attached to the intervention table. After acquiring a 3D data set the access path was planned on the CBCT workstation and shown on the intervention monitor. Then the robot was aligned to the live fluoroscopic image. A total of 40 punctures were randomly conducted on a phantom armed with several targets (diameter 2 mm) in single and double oblique trajectory (n = 20 each). Target distance, needle deviation and time for the procedures were analysed. All phantom interventions (n = 40) could be performed successfully. Mean target access path within the phantom was 8.5 cm (min 4.2 cm, max 13.5 cm). Average needle tip deviation was 1.1 mm (min 0 mm, max 4.5 mm), time duration was 3:59 min (min 2:07 min, max 10:37 min). When using the proposed robot device in a CBCT intervention suite, highly accurate needle-based interventional punctures are possible in a reasonable timely manner in single as well as in double oblique trajectories. (orig.)

  14. Idiosyncratic Presentation of Cemento-Osseous Dysplasia – An in Depth Analysis Using Cone Beam Computed Tomography

    Science.gov (United States)

    Pachigolla, Ramaswamy; Govada, Vanya Mahitha; Alapati, Satish; Balla, Smitha

    2016-01-01

    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. PMID:27437374

  15. Evaluation of danger zone in mesial root of mandibular first molar by cone beam computed tomography (CBCT)

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yoo Rhee; Choi, Yong Suk; Choi, Gi Woon; Park, Sang Hyuk [Kyung Hee Univ., Seoul (Korea, Republic of)

    2007-06-15

    To examine the danger zone of medial root of mandibular first molar of patient without extraction using CBCT (cone-beam computed tomography) to avoid the risk of root perforation. 20 mandibular first molars without caries and restorations were collected. CT images were obtained by CBCT (PSR9000N {sup T}M, Asahi Roentgen Co., Japan), reformed and analyzed by V-work 5.0 (CyberMed Inc., Korea). Distance between canal orifice and furcation was measured. In cross sectional images at 3, 4 and 5 mm below the canal office, distal wall thickness of central part (C-D), medial wall thickness of mesiobuccal canal (MB-M) and mesial wall thickness of mesiolongual canal (ML-M) were measured. The mean distance between the canal orifice and the furcation of the roots is 2.40 mm. Distal wall is found to be thinner than medial wall. Mean dentinal wall thickness of distal wall is about 1 mm. The wall thickness is thinner as the distance from the canal orifice is farther. But significant differences and not noted between 4 mm and 5 mm in MB-D and C-D. MB-D is thinner than ML-D although the differences is not significant. The present study confirmed the anatomical weakness of distal surface of the coronol part of the medial roots of mandibular first molar by CBCT and provided an anatomical guide line of wall thickness during endodontic treatment.

  16. Radiographical measurements for distal intra-articular fractures of the radius using plain radiographs and cone beam computed tomography images

    Energy Technology Data Exchange (ETDEWEB)

    Suojaervi, Nora; Lindfors, N. [Helsinki University Central Hospital, Department of Hand Surgery, Helsinki (Finland); Sillat, T.; Koskinen, S.K. [HUS Helsinki Medical Imaging Center, Helsinki University Central Hospital, Department of Radiology, Helsinki (Finland)

    2015-12-15

    Operative treatment of an intra-articular distal radius fracture is one of the most common procedures in orthopedic and hand surgery. The intra- and interobserver agreement of common radiographical measurements of these fractures using cone beam computed tomography (CBCT) and plain radiographs were evaluated. Thirty-seven patients undergoing open reduction and volar fixation for a distal radius fracture were studied. Two radiologists analyzed the preoperative radiographs and CBCT images. Agreement of the measurements was subjected to intra-class correlation coefficient and the Bland-Altman analyses. Plain radiographs provided a slightly poorer level of agreement. For fracture diastasis, excellent intraobserver agreement was achieved for radiographs and good or excellent agreement for CBCT, compared to poor interobserver agreement (ICC 0.334) for radiographs and good interobserver agreement (ICC 0.621) for CBCT images. The Bland-Altman analyses indicated a small mean difference between the measurements but rather large variation using both imaging methods, especially in angular measurements. For most of the measurements, radiographs do well, and may be used in clinical practice. Two different measurements by the same reader or by two different readers can lead to different decisions, and therefore a standardization of the measurements is imperative. More detailed analysis of articular surface needs cross-sectional imaging modalities. (orig.)

  17. Tracheomalacia before and after aortosternopexy: dynamic and quantitative assessment by electron-beam computed tomography with clinical correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kao, S.C.S. [Dept. of Radiology, The Univ. of Iowa Coll. of Medicine, Iowa City, IA (United States); Kimura, K. [Dept. of Surgery, The Univ. of Iowa Coll. of Medinice, Iowa City, IA (United States); Smith, W.L. [Dept. of Radiology, The Univ. of Iowa Coll. of Medicine, Iowa City, IA (United States); Sato, Y. [Dept. of Radiology, The Univ. of Iowa Coll. of Medicine, Iowa City, IA (United States)

    1995-11-01

    To correlate the dynamics of tracheal collapse with clinical upper airway obstruction before and after aortosternopexy, seven boys and three girls (mean age, 10 months) underwent dynamic evaluation of the trachea by electron-beam computed tomography (EBCT). The site, extent, and severity of collapse were correlated with symptomatology and details of operative procedure. When >50% area collapse was used as the criterion for tracheomalacia, segmental involvement occurred above the aortic arch in all patients, extending to the aortic arch level in only four. Tracheomalacia involved two or fewer 8-mm levels in seven patients and more than two levels in three. Eight patients underwent one aortosternopexy procedure, resulting in clinical improvement in six and correlating well with EBCT findings. Of the remaining two patients who had single aortosternopexy and did not show clinical and radiographic improvement, one required operative repair of a vascular ring and the other continued to have recurrent respiratory tract infections. On the basis of EBCT findings, two patients required additional innominate arteriopexies: One improved, and the other remained symptomatic, requiring tracheostomy. EBCT is a noninvasive modality that allows preoperative diagnosis of tracheomalacia. More importantly, the operative decision and technique are guided by an objective and quantitative assessment of tracheal collapse. (orig.)

  18. Role of Cone Beam Computed Tomography in Rehabilitation of a Traumatised Deficient Maxillary Alveolar Ridge Using Symphyseal Block Graft Placement

    Directory of Open Access Journals (Sweden)

    Shipra Arora

    2013-01-01

    Full Text Available Deficiencies in the alveolar ridges cause multiple problems in achieving aesthetic and functional outcome of implant therapy and are commonly restored by using onlay graft from intraoral source. Careful assessment of the recipient as well as the donor site using cone beam computed tomography (CBCT is a prerequisite to ideal treatment planning. This paper highlights the critical role of CBCT in planning a successful rehabilitation of traumatised deficient anterior maxillary alveolar ridge using autogenous block graft from mandibular symphysis, followed by implant placement. A 21-year-old male reported with missing right maxillary lateral incisor due to traumatic avulsion 6 months back. A concavity was found on the labial aspect of edentulous area. Serial transplanar images on CBCT revealed gross irregular radiolucency in place of labial cortical plate. Using CBCT, size of the required block was estimated, and mandibular symphyseal area was evaluated for the feasibility of harvesting a graft of suitable dimension. Onlay block graft was harvested from mandibular symphysis and placed at the edentulous site to augment the alveolar ridge. Implants were placed 5 months later and loaded successfully after osseointegration. After 1 year of followup, implant-based prosthesis is working well, without any complications.

  19. The relationship between pharyngeal morphology measured with cone-beam computed tomography and maxillary morphology measured by lateral cephalogram

    International Nuclear Information System (INIS)

    This study examined the relationship between pharyngeal morphology measured with cone-beam computed tomography (CBCT) and maxillary morphology measured from lateral cephalograms. The subjects comprised 45 women, with a mean age of 27.9 years (range, 16-50 years), who attended the Department of Orthodontics at Showa University. The evaluation of pharyngeal morphology was based on 9 variables measured by CBCT: pharyngeal space volume, pharyngeal vertical length, pharyngeal sagittal length, pharyngeal coronal length, epiglottis length, epiglottis width, the distance from the genion to the hyoidale, the distance from the hyoidale to the aditus larynges base, and the distance from the aditus larynges base to the genion. Maxillary morphology was evaluated from 5 measured sites: SNA, S'-Ptm', A'-Ptm', the occiusal plane angle, and the palatal plane angle. Pearson's correlation coefficient was used to detect associations between pharyngeal and maxillary morphological variables. There were significant correlations between pharyngeal coronal length and SNA, the distance from the genion to the hyoidale and the occlusal plane angle, pharyngeal coronal length and A'-Ptm', pharyngeal vertical length and the palatal plane angle, as well as the aditus larynges base to the genion and the occlusal plane. This information has potential clinical value for better understanding obstructive sleep apnea in adult patients, and for structurally based treatments such as surgical orthodontics. (author)

  20. Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

    Science.gov (United States)

    Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

    2016-01-01

    Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

  1. Cone-beam computed tomography analysis of the apical third of curved roots after mechanical preparation with different automated systems

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cesar Augusto Pereira; Pascoalato, Cristina [University of Southern Santa Catarina (UNISUL), Tubarao, SC (Brazil); Meurer, Maria Ines [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil); Silva, Silvio Rocha Correa, E-mail: silvio@foar.unesp.b [Sao Paulo State University (UNESP), Araraquara, SP (Brazil)

    2009-07-01

    The present study evaluated by cone-beam computed tomography (CBCT) the apical canal transportation and centralizing ability of different automated systems after root canal preparation. The mesiobuccal canals of maxillary first molars (n=10 per group) were prepared with: GI - reciprocating system with K-Flexofile; GII - reciprocating system with NiTiFlex files; GIII - rotary system with K3 instruments; GIV - rotary system with RaCe instruments. CBCT scans were taken before and after biomechanical preparation up to a 40.02 diameter. Canal transportation was determined by measuring the smallest distance between the inner canal walls and the mesial and distal sides of the root. The centralization ability corresponded to the difference between the measurements from transportation evaluation, using the linear voxel to voxel method of analysis. The mean transportation was 0.06 +- 0.14 mm, with a tendency to deviate to the mesial side of the root (n=22), with no statistically significant difference among the groups (p=0.4153). The mean centralization index was 0.15 +- 0.65 also without statistically significant difference among the groups (p=0.0881). It may be concluded that apical canal transportation and centralization ability were not influenced by the type of mechanical movement and instruments used. (author)

  2. Diagnostic performance of cone-beam computed tomography on detection of mechanically-created artificial secondary caries

    Energy Technology Data Exchange (ETDEWEB)

    Charuakkra, Arnon; Prapayasatok, Sangsom; Janhom, Apirum; Pongsirwet, Surawut; Verochana, Karune; Mahasantipiya, Phattaranant [Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand)

    2011-12-15

    The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve (Az) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). The mean Az values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest Az value. Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

  3. Auto-masked 2D/3D image registration and its validation with clinical cone-beam computed tomography

    International Nuclear Information System (INIS)

    Image-guided alignment procedures in radiotherapy aim at minimizing discrepancies between the planned and the real patient setup. For that purpose, we developed a 2D/3D approach which rigidly registers a computed tomography (CT) with two x-rays by maximizing the agreement in pixel intensity between the x-rays and the corresponding reconstructed radiographs from the CT. Moreover, the algorithm selects regions of interest (masks) in the x-rays based on 3D segmentations from the pre-planning stage. For validation, orthogonal x-ray pairs from different viewing directions of 80 pelvic cone-beam CT (CBCT) raw data sets were used. The 2D/3D results were compared to corresponding standard 3D/3D CBCT-to-CT alignments. Outcome over 8400 2D/3D experiments showed that parametric errors in root mean square were <0.18° (rotations) and <0.73 mm (translations), respectively, using rank correlation as intensity metric. This corresponds to a mean target registration error, related to the voxels of the lesser pelvis, of <2 mm in 94.1% of the cases. From the results we conclude that 2D/3D registration based on sequentially acquired orthogonal x-rays of the pelvis is a viable alternative to CBCT-based approaches if rigid alignment on bony anatomy is sufficient, no volumetric intra-interventional data set is required and the expected error range fits the individual treatment prescription. (paper)

  4. Evaluation of danger zone in mesial root of mandibular first molar by cone beam computed tomography (CBCT)

    International Nuclear Information System (INIS)

    To examine the danger zone of medial root of mandibular first molar of patient without extraction using CBCT (cone-beam computed tomography) to avoid the risk of root perforation. 20 mandibular first molars without caries and restorations were collected. CT images were obtained by CBCT (PSR9000N TM, Asahi Roentgen Co., Japan), reformed and analyzed by V-work 5.0 (CyberMed Inc., Korea). Distance between canal orifice and furcation was measured. In cross sectional images at 3, 4 and 5 mm below the canal office, distal wall thickness of central part (C-D), medial wall thickness of mesiobuccal canal (MB-M) and mesial wall thickness of mesiolongual canal (ML-M) were measured. The mean distance between the canal orifice and the furcation of the roots is 2.40 mm. Distal wall is found to be thinner than medial wall. Mean dentinal wall thickness of distal wall is about 1 mm. The wall thickness is thinner as the distance from the canal orifice is farther. But significant differences and not noted between 4 mm and 5 mm in MB-D and C-D. MB-D is thinner than ML-D although the differences is not significant. The present study confirmed the anatomical weakness of distal surface of the coronol part of the medial roots of mandibular first molar by CBCT and provided an anatomical guide line of wall thickness during endodontic treatment

  5. Three-dimensional observations of the incisive canal and the surrounding bone using cone-beam computed tomography

    International Nuclear Information System (INIS)

    The shape of the anterior region of the maxilla is critical when planning implant treatment. The purpose of the present study was to assess the typical morphology of the incisive canal and surrounding bone. In total, 70 maxillae of Japanese dry skulls were used after being divided into dentate and edentulous groups. Cone-beam computed tomography (CBCT) images of the maxilla were acquired by using standardized methods. Using the anterior nasal spine as a reference point, the change in position was measured and analyzed statistically. Also, three-dimensional (3-D) images of the incisive canal were classified into five subsets: cylinder, groove, penetration, bifurcation at the superior portion, and bifurcation at the inferior portion. The quantity of alveolar bone in the incisor region was greatly reduced from the alveolar ridge and labial surface. Moreover, the vertical position of the incisive foramen was significantly (P<0.05) superior in the edentulous groups. Regarding the classification of maxillae by the 3-D shape of the incisive canal, many canals were cylindrical. Horizontal bone reduction from the labial side and vertical bone reduction from the alveolar crest were conspicuous; thus, the angle of the anterior alveolar bone changed after the loss of teeth. The incisive canal diameter in the edentulous group was larger than in the dentate group. The nondestructive assessment of the incisive canals and surrounding bone with CBCT showed two typical shapes for the presence or absence of the incisors. These findings indicate the importance of image diagnosis before esthetic restoration. (author)

  6. Staged ridge-split evaluated using cone beam computed tomography and peri-implant plastic surgery in the mandibular arch

    Directory of Open Access Journals (Sweden)

    Nikhil Vasant Jain

    2015-01-01

    Full Text Available Lack of sufficient bone to place an implant at a functionally and an esthetically appropriate position is a common problem, especially in the mandibular posterior region. Narrow edentulous alveolar ridges <5 mm wide require bone augmentation before implant placement to establish a bony wall of at least 1 mm around the endosseous implant. Various surgical widening techniques are available, including lateral augmentation with or without guided bone regeneration, ridge-split technique and horizontal distraction osteogenesis. The ridge-split technique aims at creating a new implant bed by longitudinal osteotomy of the alveolar bone. The buccal cortex is repositioned laterally by greenstick fracture, and the space between the buccal and lingual cortices is filled with a graft material. Peri-implant plastic surgery focuses on harmonizing peri-implant structures by means of hard- and soft-tissue engineering and includes bone structure enhancement, soft-tissue enhancement, precision in implant placement and improves quality of the prosthetic restoration. The rationale for the peri-implant plastic surgery approach goes well beyond pure esthetics as it creates peri-implant keratinized mucosa and interimplant soft-tissue height in order to avoid food impaction, interimplant airflow, and speech problems. This case report demonstrates a staged ridge-split technique evaluated with cone beam computed tomography using a piezosurgical unit and a surgical technique to restore a papilla-like tissue at the time of the second-stage implant surgery.

  7. Observation of the anterior loop and mental foramen of the mandibular canal using cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Kwang Jun; Kim, Kyoung A [Department of Oral and Maxillofacial Radiology, School of Dentistry, and Institute of Oral Bioscience, Chonbuk National University, Jeonju (Korea, Republic of)

    2009-06-15

    To evaluate the anteroposterior length and buccal angle of the anterior loop, and the size and location of the mental foramen using cone beam computed tomography (CBCT). 100 CBCT images from 87 adults (43 males and 44 females) ranging in age from 20 to 73 years (average 50 years) with edentulous ridge of the mandibular premolar region were obtained. Axial, sagittal, coronal images were reconstructed from Dental and Block Images of CBCT. The anteroposterior length, shape and buccal angle of the anterior loop, and the size and location of the mental foramen were calculated from reconstructed images of axial, sagittal and coronal CBCT. The anteroposterior length and buccal angle of the mental canal was 4.0 {+-} 1.2 mm, 37.8 {+-} 11.6 .deg. C respectively. The loop type with straight course was the most common shape of the mental canal. The location of the mental foramen below the apex of the lower second premolar (78%) was the most common. The maximum size of the mental foramen was 4.6 {+-} 1.0 mm in width and 3.0 {+-} 0.6 mm in height. The inner size of the mental canal was 2.6 {+-} 0.6 mm in width and 2.1 mm {+-} 0.4 mm in height. CBCT is useful to evaluate the anterior loop and mental foramen of the mandibular canal. Safe guideline of 4 mm from the most anterior point of the mental foramen is recommended for implant and surgical treatment.

  8. Regenerative Endodontic Treatment of an Infected Immature Dens Invaginatus with the Aid of Cone-Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Işıl Kaya-Büyükbayram

    2014-01-01

    Full Text Available Dens invaginatus is a developmental anomaly that results in an enamel-lined cavity intruding into the crown or root before the mineralization phase. This report presents regenerative endodontic treatment of a necrotic immature tooth with Oehler’s type III dens invaginatus of a nine-year-old female patient. A diagnosis of dens invaginatus (Oehler’s type III and a large periapical lesion was established with the aid of cone-beam computed tomography (CBCT. In the presented case contrary to the classic revascularization protocol, mechanical instrumentation was performed which apparently did not interfere with the regeneration process. After mechanical instrumentation of the invaginated canal by manual K-files, the invaginated canal space was disinfected by triple antibiotic paste followed by blood clot induction from the periapical tissues and the placement of mineral trioxide aggregate. At one-year follow-up, the tooth remained clinically asymptomatic. Radiographic examination revealed complete healing of the periapical lesion. At the 20-month follow-up, the radiographic examination also showed that the open apex was closed and the walls of the root canal were thickened.

  9. Guided access cavity preparation using cone-beam computed tomography and optical surface scans - an ex vivo study

    DEFF Research Database (Denmark)

    Buchgreitz, J; Buchgreitz, M; Mortensen, D;

    2016-01-01

    AIM: To evaluate ex vivo, the accuracy of a preparation procedure planned for teeth with pulp canal obliteration (PCO) using a guide rail concept based on a cone-beam computed tomography (CBCT) scan merged with an optical surface scan. METHODOLOGY: A total of 48 teeth were mounted in acrylic blocks....... An apical canal preparation was created to simulate remnants of an apical root canal that acted as the target for a drill path. The test blocks were surface scanned, and merged with a CBCT scan, and a guide rail was made. A pathway for the bur was created through a metal sleeve within the guide rail...... into dentine. The distance was measured between the centres of the performed drill path and the apical target by two examiners. A maximum distance of 0.7 mm was defined based on the radius of the bur (0.6 mm) and the radius of a root canal just visible on a radiograph (0.1 mm). The t-test was used for...

  10. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... ray beam follows a spiral path. A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body, which are then displayed on a ... by computer software, the result is a very detailed multidimensional ...

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... ray beam follows a spiral path. A special computer program processes this large volume of data to create two-dimensional cross-sectional images of your body, which are then displayed on a ... by computer software, the result is a very detailed multidimensional ...

  12. Successful treatment of a free-moving abdominal mass with radiation therapy guided by cone-beam computed tomography: a case report

    Directory of Open Access Journals (Sweden)

    Shihadeh Ferial

    2010-10-01

    Full Text Available Abstract Introduction Because tumors in the abdomen can change position, targeting these tumors for radiation therapy should be done with caution; use of daily image-guided radiation therapy is advised. Case presentation We report the case of a 72-year-old Caucasian man with recurrent mantle cell lymphoma who was referred for palliative radiation therapy for an abdominopelvic tumor. Computed tomography was used to generate images for radiation treatment planning. Comparison of those planning images with a positron emission tomography/computed tomography scan ordered during the planning period revealed that the tumor had moved from one side of the abdomen to the other during the three-day interval between scans. To account for this unusual tumor movement, we obtained a second set of planning computed tomography scans and used a Varian cone-beam computed tomography scanner with on-board imaging capability to target the tumor before each daily treatment session, leading to successful treatment and complete resolution of the mass. Conclusion Abdominal masses associated with the mesentery should be considered highly mobile; thus, radiation therapy for such masses should be used with the utmost caution. Modern radiation therapy techniques offer the ability to verify the tumor location in real time and shift the treatment ports accordingly over the course of treatment.

  13. Characterization of Scattered X-Ray Photons in Dental Cone-Beam Computed Tomography

    Science.gov (United States)

    Yang, Ching-Ching

    2016-01-01

    Purpose 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. Methods 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). Results 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. Conclusions 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. PMID:26950435

  14. 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.

  15. Cone beam computed tomography in veterinary dentistry: description and standardization of the technique; Tomografia computadorizada de feixe conico na odontologia veterinaria: descricao e padronizacao da tecnica

    Energy Technology Data Exchange (ETDEWEB)

    Roza, Marcello R. [Universidade Federal de Goias (UFG), Goianai, GO (Brazil)], e-mail: marcelloroza@gmail.com; Silva, Luiz A.F.; Fioravanti, Maria C. S. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Escola de Veterinaria. Dept. de Medicina Veterinaria; Januario, Alessandro L. [International Team for Implantology (ITI), Sao Paulo, SP (Brazil); Barriviera, Mauricio [Universidade Catolica de Brasilia (UCB), DF (Brazil). Faculdade de Odontologia. Dept. de Radiologia; Oliveira, Alexandre C.A. [Faculdade de Odontologia Sao Leopoldo Mandic, Campinas, SP (Brazil)

    2009-08-15

    Eleven dogs and four cats with buccodental alterations, treated in the Centro Veterinario do Gama, in Brasilia, DF, Brazil, were submitted to cone beam computed tomography. The exams were carried out in a i-CAT tomograph, using for image acquisition six centimeters height, 40 seconds time, 0.2 voxel, 120 kilovolts and 46.72 milli amperes per second. The ideal positioning of the animal for the exam was also determined in this study and it proved to be fundamental for successful examination, which required a simple and safe anesthetic protocol due to the relatively short period of time necessary to obtain the images. Several alterations and diseases were identified with accurate imaging, demonstrating that cone beam computed tomography is a safe, accessible and feasible imaging method which could be included in the small animal dentistry routine diagnosis. (author)

  16. An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries

    Energy Technology Data Exchange (ETDEWEB)

    Kayipmaz, Saadettin, E-mail: kayipmaz@ktu.edu.tr [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Sezgin, Omer Said, E-mail: omersaidsezgin@gmail.com [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Saricaoglu, Senem Tugra, E-mail: senem_tugra@hotmail.com [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Diagnosis and Radiology, Farabi, 61080 Trabzon (Turkey); Can, Gamze, E-mail: gcanktu@yahoo.com [Karadeniz Technical University Faculty of Medicine Department of Public Health (Turkey)

    2011-11-15

    Aim: The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries. Methods: A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8x magnification. Results: CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found. Conclusion: The CBCT system may be used as an auxiliary method for the detection of caries.

  17. An in vitro comparison of diagnostic abilities of conventional radiography, storage phosphor, and cone beam computed tomography to determine occlusal and approximal caries

    International Nuclear Information System (INIS)

    Aim: The aim of this study was to compare conventional radiography, storage phosphor plate, and cone beam computed tomography for in vitro determination of occlusal and approximal caries. Methods: A total of 72 extracted human premolar and molar teeth were selected. Teeth were radiographed with conventional intraoral radiography, a storage phosphor plate system, and cone beam computed tomography and evaluated by two observers. The teeth were then separated and examined with a stereomicroscope and a scanner at approximately 8x magnification. Results: CBCT was statistically superior to conventional radiography and phosphor plate for determining occlusal caries. No significant difference from CBCT, conventional radiography and the phosphor plate system for determining approximal caries was found. Conclusion: The CBCT system may be used as an auxiliary method for the detection of caries.

  18. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  19. Cone-beam computed tomography based evaluation of rotational patterns of dentofacial structures in skeletal Class III deformity with mandibular asymmetry

    OpenAIRE

    Ryu, Hyeong-Seok; An, Ki-Yong; Kang, Kyung-Hwa

    2015-01-01

    Objective The purpose of this study was to assess rotational patterns of dentofacial structures according to different vertical skeletal patterns by cone-beam computed tomography (CBCT) and analyze their influence on menton deviation in skeletal Class III deformity with mandibular asymmetry. Methods The control group consisted of 30 young adults (15 men, 15 women) without any severe skeletal deformity. The asymmetry group included 55 adults (28 men, 27 women) with skeletal Class III deformity...

  20. Evaluation of the neurovascular bundle position at the palate with cone beam computed tomography: an observational study

    OpenAIRE

    Yilmaz, Hasan Guney; Ayali, Aysa

    2015-01-01

    Background The aim of this study was to investigate the neurovascular bundle (NVB) position with cone-beam computerized tomography (CBCT). Methods CBCT images of 345 patients were evaluated. The distance from the neurovascular bundle to the cemento-enamel junction (CEJ) was measured (DNB). The distance from mid-palatal suture to the alveolar crest was used to determine the palatal depth. Palatal junction angle (PA) was measured using the junction angle between the hard palate and alveolar cre...

  1. Computed Tomography Status

    Science.gov (United States)

    Hansche, B. D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  2. Computed Tomography. Chapter 11

    International Nuclear Information System (INIS)

    After its clinical introduction in 1971, computed tomography (CT) developed from an X ray modality that was limited to axial imaging of the brain in neuroradiology into a versatile 3-D whole body imaging modality for a wide range of applications, including oncology, vascular radiology, cardiology, traumatology and interventional radiology. CT is applied for diagnosis and follow-up studies of patients, for planning of radiotherapy, and even for screening of healthy subpopulations with specific risk factors

  3. Megavoltage cone beam computed tomography: commissioning and evaluation of patient dose

    International Nuclear Information System (INIS)

    The improvement in conformal radiotherapy techniques enables us to achieve steep dose gradients around the target which allows the delivery of higher doses to a tumor volume while maintaining the sparing of surrounding normal tissue. One of the reasons for this improvement was the implementation of intensity-modulated radio therapy (IMRT) by using linear accelerators fitted with multi-leaf collimator (MLC), Tomo therapy and Rapid arc. In this situation, verification of patient set-up and evaluation of internal organ motion just prior to radiation delivery become important. To this end, several volumetric image-guided techniques have been developed for patient localization, such as Siemens OPTIVUE/MVCB and MVision megavoltage cone beam CT (MV-CBCT) system. Quality assurance for MV-CBCT is important to insure that the performance of the Electronic portal image device (EPID) and MV-CBCT is suitable for the required treatment accuracy. In this work, the commissioning and clinical implementation of the OPTIVUE/MVCB system was presented. The geometry and gain calibration procedures for the system were described. The image quality characteristics of the OPTIVUE/MVCB system were measured and assessed qualitatively and quantitatively, including the image noise and uniformity, low-contrast resolution, and spatial resolution. The image reconstruction and registration software were evaluated. Dose at isocenter from CBCT and the EPID were evaluated using ionization chamber and thermo-luminescent dosimeters; then compared with that calculated by the treatment planning system (TPS- XiO 4.4). The results showed that there are no offsets greater than 1 mm in the flat panel alignment in the lateral and longitudinal direction over 18 months of the study. The image quality tests showed that the image noise and uniformity were within the acceptable range, and that a 2 cm large object with 1% electron density contrast can be detected with the OPTIVUE/MVCB system with 5 monitor units (MU

  4. Isotope computed tomography using cone-beam geometry: a comparison of two reconstruction algorithms

    International Nuclear Information System (INIS)

    A CT scanner has been constructed specifically to determine the three-dimensional distribution of bone mineral in the medullary cavities of the radius, ulna and femur. A source of x-rays (153Gd) and a multiwire proportional counter (MWPC) are mounted at opposite ends of a diameter of an annular mounting. The limb is placed on the axis of rotation of the annulus and a series of two-dimensional transmission projections are obtained at equal angular spacings over 3600. Distribution of bone mineral is reconstructed from the projections either by maximum entropy (ME) or by convolution and back projection (CBP). These two methods have been evaluated by reconstructing a single slice of a phantom, representing the forearm, from projection simulated by computer. With a clinically acceptable exposure time, the mean medullary densities of the ulna and radius were determined with systematic errors of less than 3.5% (ME) and 11% (CBP), although for the latter method of reconstruction the systematic error was reduced to less than 2% by increasing the number of views. The mean medullary densities of the ulna and radius were determined with precisions better than 2.5% (ME) and 3.5% (CBP). (author)

  5. Cone beam computed tomography analysis of root and canal morphology of mandibular premolars in a Spanish population

    International Nuclear Information System (INIS)

    This study aimed to investigate the clinical anatomy of lower premolar roots in a Spanish population by using cone-beam computed tomography (CBCT), correlating findings with patient gender and tooth type. Using 70 CBCT images, we evaluated 126 healthy, untreated, well-developed lower premolars. The number and morphology of roots and root canals, and the foramina number were assessed. Results for gender and tooth type were compared using the chi-squared and ANOVA tests. The average length of teeth and roots was significantly higher in men (p=0.00). All 126 premolars had a single root. One canal was found in 83.3% of the premolars, with no gender or tooth type differences; Vertucci configuration types I and V were the most prevalent. The first premolars showed significantly greater variability than the second premolars (p=0.03). A single apical foramen was found in 89.7% of the premolars, with no differences by tooth type. Women had a significantly higher prevalence of two apical foramina than men (p=0.04). Some degree of curvature was observed in 65% of the premolars, with no differences by gender or tooth type. A root angle of more than 20 degrees was found in 12.98% of the premolars, without any differences by gender or tooth. All premolars were single-rooted. One canal had the most prevalent morphology. More variability in canal anatomy was found in the first premolars. Curvatures greater than 20 degrees were found at less than 5 mm from the apex.

  6. Daily cone-beam computed tomography used to determine tumour shrinkage and localisation in lung cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Marquard Knap, Marianne; Nordsmark, Marianne (Aarhus Univ. Hospital, Dept. of Oncology, Aarhus (Denmark)), E-mail: mariknap@rm.dk; Hoffmann, Lone; Vestergaard, Anne (Aarhus Univ. Hospital, Dept. of Medical Physics, Aarhus (Denmark))

    2010-10-15

    Purpose/Objective. Daily Cone-beam computed tomography (CBCT) in room imaging is used to determine tumour shrinkage during a full radiotherapy (RT) course. In addition, relative interfractional tumour and lymph node motion is determined for each RT fraction. Material and methods. From November 2009 to March 2010, 20 consecutive lung cancer patients (14 NSCLC, 6 SCLC) were followed with daily CBCT during RT. The gross tumour volume for lung tumour (GTV-t) was visible in all daily CBCT scans and was delineated at the beginning, at the tenth and the 20th fraction, and at the end of treatment. Whenever visible, the gross tumour volume for lymph nodes (GTV-n) was also delineated. The GTV-t and GTV-n volumes were determined. All patients were setup according to an online bony anatomy match. Retrospectively, matching based on the internal target volume (ITV), the GTV-t or the GTV-n was performed. Results. In eight patients, we observed a significant GTV-t shrinkage (15-40%) from the planning CT until the last CBCT. Only five patients presented a significant shrinkage (21-37%) in the GTV-n. Using the daily CBCT imaging, it was found that the mean value of the difference between a setup using the skin tattoo and an online matching using the ITV was 7.3+-2.9 mm (3D vector in the direction of ITV). The mean difference between the ITV and bony anatomy matching was 3.0+-1.3 mm. Finally, the mean distance between the GTV-t and the GTV-N was 2.9+-1.6 mm. Conclusion. One third of all patients with lung cancer undergoing chemo-RT achieved significant tumour shrinkage from planning CT until the end of the radiotherapy. Differences in GTV-t and GTV-n motion was observed and matching using the ITV including both GTV-t and GTV-n is therefore preferable.

  7. Feasibility Study of Needle Placement in Percutaneous Vertebroplasty: Cone-Beam Computed Tomography Guidance Versus Conventional Fluoroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Braak, Sicco J., E-mail: sjbraak@gmail.com [St. Antonius Hospital, Department of Radiology (Netherlands); Zuurmond, Kirsten, E-mail: kirsten.zuurmond@philips.com; Aerts, Hans C. J., E-mail: hans.cj.aerts@philips.com [Philips Medical, Department of Clinical Development (Netherlands); Leersum, Marc van, E-mail: m.van.leersum@antoniusziekenhuis.nl; Overtoom, Timotheus T. Th., E-mail: overtm@knoware.nl; Heesewijk, Johannes P. M. van, E-mail: j.heesewijk@antoniusziekenhuis.nl; Strijen, Marco J. L. van, E-mail: m.van.strijen@antoniusziekenhuis.nl [St. Antonius Hospital, Department of Radiology (Netherlands)

    2013-08-01

    ObjectiveTo investigate the accuracy, procedure time, fluoroscopy time, and dose area product (DAP) of needle placement during percutaneous vertebroplasty (PVP) using cone-beam computed tomography (CBCT) guidance versus fluoroscopy.Materials and MethodsOn 4 spine phantoms with 11 vertebrae (Th7-L5), 4 interventional radiologists (2 experienced with CBCT guidance and two inexperienced) punctured all vertebrae in a bipedicular fashion. Each side was randomization to either CBCT guidance or fluoroscopy. CBCT guidance is a sophisticated needle guidance technique using CBCT, navigation software, and real-time fluoroscopy. The placement of the needle had to be to a specific target point. After the procedure, CBCT was performed to determine the accuracy, procedure time, fluoroscopy time, and DAP. Analysis of the difference between methods and experience level was performed.ResultsMean accuracy using CBCT guidance (2.61 mm) was significantly better compared with fluoroscopy (5.86 mm) (p < 0.0001). Procedure time was in favor of fluoroscopy (7.39 vs. 10.13 min; p = 0.001). Fluoroscopy time during CBCT guidance was lower, but this difference is not significant (71.3 vs. 95.8 s; p = 0.056). DAP values for CBCT guidance and fluoroscopy were 514 and 174 mGy cm{sup 2}, respectively (p < 0.0001). There was a significant difference in favor of experienced CBCT guidance users regarding accuracy for both methods, procedure time of CBCT guidance, and added DAP values for fluoroscopy.ConclusionCBCT guidance allows users to perform PVP more accurately at the cost of higher patient dose and longer procedure time. Because procedural complications (e.g., cement leakage) are related to the accuracy of the needle placement, improvements in accuracy are clinically relevant. Training in CBCT guidance is essential to achieve greater accuracy and decrease procedure time/dose values.

  8. Assessment of the anterior loop of the mandibular canal: A study using cone-beam computed tomography

    Science.gov (United States)

    do Nascimento, Eduarda Helena Leandro; dos Anjos Pontual, Maria Luiza; dos Anjos Pontual, Andréa; da Cruz Perez, Danyel Elias; Figueiroa, José Natal; Frazão, Marco Antônio Gomes

    2016-01-01

    Purpose Sufficient area in the interforaminal region is required for dental implant placement, and the anterior loop of the mandibular canal is located within the limits of this area. The aim of this study was to evaluate the prevalence and extent of the anterior loop in a Brazilian sample population using cone-beam computed tomography (CBCT). Materials and Methods CBCT images from 250 patients (500 hemimandibles) obtained for various clinical indications were randomly selected and evaluated to determine the presence and length of the anterior loop. The length of the anterior loop was then compared based on gender, age, and the side of the mandible. The data were analyzed using the Pearson chi-square test and linear regression analysis. Results An anterior loop was identified in 41.6% of the cases, and its length ranged from 0.25 mm to 4.00 mm (mean, 1.1±0.8 mm). The loop had a greater mean length and was significantly more prevalent in males (p=0.014). No significant differences were found between the right and left sides regarding length (p=0.696) or prevalence (p=0.650). Conclusion In this study, a high prevalence of the anterior loop of the mandibular canal was found, and although its length varied greatly, in most cases it was less than 1 mm long. Although this is a prevalent anatomical variation, safety limits for the placement of implants in this region cannot be established before an accurate evaluation using imaging techniques in order to identify and preserve the neurovascular bundles. PMID:27358813

  9. The incidence and configuration of the bifid mandibular canal in Koreans by using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ju Han; Lee, Kook Sun; Oh, Min Gyu; Choi, Hwa Young; Lee, Sae Rom; Oh, Song Hee; Choi, Yoon Joo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)

    2014-03-15

    This study was performed to investigate the incidence and configuration of the bifid mandibular canal in a Korean population by using cone-beam computed tomography (CBCT) imaging. CBCT images of 1933 patients (884 male and 1049 female) were evaluated using PSR-9000N and Alphard-Vega 3030 Dental CT units (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan). Image analysis was performed by using OnDemand3D software (CyberMed Inc., Seoul, Korea). The bifid mandibular canal was identified and classified into four types, namely, the forward canal, buccolingual canal, dental canal, and retromolar canal. Statistical analysis was performed by using the chi-squared test and one-way analysis of variance (ANOVA). Bifid mandibular canals were observed in 198 (10.2%) of 1933 patients. The most frequently observed type of bifid mandibular canal was the retromolar canal (n=104, rate: 52.5%) without any significant difference among the incidence of each age and gender. The mean diameter of the accessory canal was 1.27 mm (range: 0.27-3.29 mm) without any significant difference among the mean diameter of each type of the bifid mandibular canal. The mean length of the bifid mandibular canals was 14.97mm(range: 2.17-38.8 mm) with only a significant difference between the dental canal and the other types. The bifid mandibular canal is not uncommon in Koreans and has a prevalence of 10.2% as indicated in the present study. It is suggested that a CBCT examination be recommended for detecting a bifid canal.

  10. A local shift-variant Fourier model and experimental validation of circular cone-beam computed tomography artifacts.

    Science.gov (United States)

    Bartolac, Steven; Clackdoyle, Roll; Noo, Frederic; Siewerdsen, Jeff; Moseley, Douglas; Jaffray, David

    2009-02-01

    Large field of view cone-beam computed tomography (CBCT) is being achieved using circular source and detector trajectories. These circular trajectories are known to collect insufficient data for accurate image reconstruction. Although various descriptions of the missing information exist, the manifestation of this lack of data in reconstructed images is generally nonintuitive. One model predicts that the missing information corresponds to a shift-variant cone of missing frequency components. This description implies that artifacts depend on the imaging geometry, as well as the frequency content of the imaged object. In particular, objects with a large proportion of energy distributed over frequency bands that coincide with the missing cone will be most compromised. These predictions were experimentally verified by imaging small, localized objects (acrylic spheres, stacked disks) at varying positions in the object space and observing the frequency spectrums of the reconstructions. Measurements of the internal angle of the missing cone agreed well with theory, indicating a right circular cone for points on the rotation axis, and an oblique, circular cone elsewhere. In the former case, the largest internal angle with respect to the vertical axis corresponds to the (half) cone angle of the CBCT system (typically approximately 5 degrees - 7.5 degrees in IGRT). Object recovery was also found to be strongly dependent on the distribution of the object's frequency spectrum relative to the missing cone, as expected. The observed artifacts were also reproducible via removal of local frequency components, further supporting the theoretical model. Larger objects with differing internal structures (cellular polyurethane, solid acrylic) were also imaged and interpreted with respect to the previous results. Finally, small animal data obtained using a clinical CBCT scanner were observed for evidence of the missing cone. This study provides insight into the influence of incomplete

  11. Bilateral cleft lip and palate: A morphometric analysis of facial skeletal form using cone beam computed tomography.

    Science.gov (United States)

    Starbuck, John M; Ghoneima, Ahmed; Kula, Katherine

    2015-07-01

    Bilateral cleft lip and palate (BCLP) is caused by a lack of merging of maxillary and nasal facial prominences during development and morphogenesis. BCLP is associated with congenital defects of the oronasal facial region that can impair ingestion, mastication, speech, and dentofacial development. Using cone beam computed tomography (CBCT) images, 7- to 18-year old individuals born with BCLP (n = 15) and age- and sex-matched controls (n = 15) were retrospectively assessed. Coordinate values of three-dimensional facial skeletal anatomical landmarks (n = 32) were measured from each CBCT image. Data were evaluated using principal coordinates analysis (PCOORD) and Euclidean Distance Matrix Analysis (EDMA). PCOORD axes 1-3 explain approximately 45% of the morphological variation between samples, and specific patterns of morphological differences were associated with each axis. Approximately, 30% of facial skeletal measures significantly differ by confidence interval testing (α = 0.10) between samples. While significant form differences occur across the facial skeleton, strong patterns of differences are localized to the lateral and superioinferior aspects of the nasal aperture. In conclusion, the BCLP deformity significantly alters facial skeletal morphology of the midface and oronasal regions of the face, but morphological differences were also found in the upper facial skeleton and to a lesser extent, the lower facial skeleton. This pattern of strong differences in the oronasal region of the facial skeleton combined with differences across the rest of the facial complex underscores the idea that bones of the craniofacial skeleton are integrated. PMID:25752824

  12. Cone-beam computed tomography arthrography: an innovative modality for the evaluation of wrist ligament and cartilage injuries

    International Nuclear Information System (INIS)

    Cone-beam computed tomography (CBCT) has become an important modality in dento-facial imaging but remains poorly used in the exploration of the musculoskeletal system. The purpose of this study was to prospectively evaluate the performance and radiation exposure of CBCT arthrography in the evaluation of ligament and cartilage injuries in cadaveric wrists, with gross pathology findings as the standard of reference. Conventional arthrography was performed under fluoroscopic guidance on 10 cadaveric wrists, followed by MDCT acquisition and CBCT acquisition. CBCT arthrography and MDCT arthrography images were independently analyzed by two musculoskeletal radiologists working independently and then in consensus. The following items were observed: scapholunate and lunotriquetral ligaments, triangular fibrocartilage complex (TFCC) (tear, integrity), and proximal carpal row cartilage (chondral tears). Wrists were dissected and served as the standard of reference for comparisons. Interobserver agreement, sensitivity, specificity, and accuracy were determined. Radiation dose (CTDI) of both modalities was recorded. CBCT arthrography provides equivalent results to MDCT arthrography in the evaluation of ligaments and cartilage with sensitivity and specificity between 82 and 100%, and interobserver agreement between 0.83 and 0.97. However, radiation dose was significantly lower (p < 0.05) for CBCT arthrography than for MDCT arthrography with a mean CTDI of 2.1 mGy (range 1.7-2.2) versus a mean of 15.1 mGy (range 14.7-16.1). CBCT arthrography appears to be an innovative alternative to MDCT arthrography of the wrist as it allows an accurate and low radiation dose evaluation of ligaments and cartilage. (orig.)

  13. Cone-Beam Computed Tomography (CBCT) Hepatic Arteriography in Chemoembolization for Hepatocellular Carcinoma: Performance Depicting Tumors and Tumor Feeders

    International Nuclear Information System (INIS)

    PurposeThis study was designed to analyze retrospectively the performance of cone-beam computed tomography (CBCT) hepatic arteriography in depicting tumors and their feeders and to investigate the related determining factors in chemoembolization for hepatocellular carcinoma (HCC).MethodsEighty-six patients with 142 tumors satisfying the imaging diagnosis criteria of HCC were included in this study. The performance of CBCT hepatic arteriography for chemoembolization per tumor and per patient was evaluated using maximum intensity projection images alone (MIP analysis) or MIP combined with multiplanar reformation images (MIP + MPR analysis) regarding the following three aspects: tumor depiction, confidence of tumor feeder detection, and trackability of tumor feeders. Tumor size, tumor enhancement, tumor location, number of feeders, diaphragmatic motion, portal vein enhancement, and hepatic artery to parenchyma enhancement ratio were regarded as potential determining factors.ResultsTumors were depicted in 125 (88.0 %) and 142 tumors (100 %) on MIP and MIP + MPR analysis, respectively. Imaging performances on MIP and MIP + MPR analysis were good enough to perform subsegmental chemoembolization without additional angiographic investigation in 88 (62.0 %) and 128 tumors (90.1 %) on per-tumor basis and in 43 (50 %) and 73 (84.9 %) on per-patient basis, respectively. Significant determining factors for performance in MIP + MPR analysis on per tumor basis were tumor size (p = 0.030), tumor enhancement (0.005), tumor location (p = 0.001), and diaphragmatic motion (p < 0.001).ConclusionsCBCT hepatic arteriography provided sufficient information for subsegmental chemoembolization by depicting tumors and their feeders in the vast majority of patients. Combined analysis of MIP and MPR images was essential to enhance the performance of CBCT hepatic arteriography

  14. Cone beam computed tomography analysis of root and canal morphology of mandibular premolars in a Spanish population

    Energy Technology Data Exchange (ETDEWEB)

    Llena, Carmen; Ortolani, Pablo Sebastian; Forner, Leopoldo [Dept. of of Stomatology, Universitat de Valencia, Valencia (Spain); Fernandez, Jaime [Ferneandez Ugedo y Chaves Clinic, Alicante (Spain)

    2014-09-15

    This study aimed to investigate the clinical anatomy of lower premolar roots in a Spanish population by using cone-beam computed tomography (CBCT), correlating findings with patient gender and tooth type. Using 70 CBCT images, we evaluated 126 healthy, untreated, well-developed lower premolars. The number and morphology of roots and root canals, and the foramina number were assessed. Results for gender and tooth type were compared using the chi-squared and ANOVA tests. The average length of teeth and roots was significantly higher in men (p=0.00). All 126 premolars had a single root. One canal was found in 83.3% of the premolars, with no gender or tooth type differences; Vertucci configuration types I and V were the most prevalent. The first premolars showed significantly greater variability than the second premolars (p=0.03). A single apical foramen was found in 89.7% of the premolars, with no differences by tooth type. Women had a significantly higher prevalence of two apical foramina than men (p=0.04). Some degree of curvature was observed in 65% of the premolars, with no differences by gender or tooth type. A root angle of more than 20 degrees was found in 12.98% of the premolars, without any differences by gender or tooth. All premolars were single-rooted. One canal had the most prevalent morphology. More variability in canal anatomy was found in the first premolars. Curvatures greater than 20 degrees were found at less than 5 mm from the apex.

  15. Using cone-beam computed tomography to evaluate the impact of bladder filling status on target position in prostate radiotherapy

    International Nuclear Information System (INIS)

    Purpose: to assess bladder filling status and its impact on target position during daily intensity-modulated radiation therapy (IMRT) using cone-beam computed tomography (CBCT) in prostate cancer patients. Patients and methods: 23 patients with prostate cancer undergoing image-guided IMRT (78 Gy in 39 fractions) were included. On-board CBCT images were acquired daily and an endorectal balloon was placed daily. All patients were instructed to have a full bladder. The interfraction changes in bladder dimensions in left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions were measured from CBCT images. Distances from the uppermost part of prostate to pubic bone (PP) and from the uppermost part of prostate to treatment isocenter (PI) were measured to determine changes in target position. Standard deviation (SD) in all fractions of each patient was used to compare the variations between patients. Bladder dimension change ratio and Z-score were used to normalize data between patients. Results: a total of 867 CBCT images were evaluated. The average LR, AP, and SI bladder dimensions were 7.8 ± 1.5 cm, 6.7 ± 1.4 cm, and 5.6 ± 1.7 cm, respectively. The average LR, AP, and SI bladder dimension change ratios were 0.88 ± 0.17, 0.90 ± 0.15, and 0.86 ± 0.32, respectively. The SD was significantly greater in SI dimension than in LR (p < 0.001) and AP (p < 0.001) dimensions. The interfraction changes in the three bladder dimensions were significantly larger than those of target position, and did not correlate with target position changes. Conclusion: though they were not negligible, changes in bladder filling status did not have a significant impact on target position. (orig.)

  16. A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

    Energy Technology Data Exchange (ETDEWEB)

    Haghanifar, Sina; Moudi, Ehsan; Mesgarani, Abbas; Abbaszadeh, Naghi [Dental Material Research Center, Dental Faculty, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of); Bijani, Ali [Non-Communicable Pediatric Diseases Research Center, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of)

    2014-06-15

    The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ({sup r}oot perforation{sup )}. Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

  17. Cone Beam Computed Tomography Study of Root and Canal Morphology of Maxillary first Molar in an Iranian Population

    Directory of Open Access Journals (Sweden)

    Faramarzi

    2015-06-01

    Full Text Available Background The success of endodontic treatment depends on detection of all root canals so that they could be cleaned, shaped and obturated appropriately. To achieve this, it is essential to know root canals complexities such as the number of canals and types of each root canal, which are genetically determined. Besides, the highest failure rates occur in maxillary first molars. Objectives Therefore, the aim of this study was to investigate the root and canal morphology of maxillary first molars in an Iranian population using cone-beam computed tomography (CBCT. Materials and Methods In this study, images of 156 extracted maxillary first molars placed in the waxed blocks were produced using CBCT. Two professional investigators checked images by NNT software in New Tom 3G system. Axial view and cross section of 1 mm thickness were used. The number of roots, canals, each roots canal, MB1-MB2 orifice distances and canal types of the Vertucci classification were recorded. Finally, data was analyzed using SPSS16 software. Results We found 100% of cases with three separated roots, from which 69.23% had four canals including MB2 and 30.77% with three canals. 71.3% of mesiobuccal roots were two canals of type two Vertucci and 28.7% type 4 with the mean distance value of 2.55 ± 0.57 mm between MB1 and MB2 orifice. Conclusions Most extracted maxillary first molars were three rooted and four canals. CBCT has relatively high reproducibility and accuracy of distinguishing MB2 canal.

  18. Cone-Beam Computed Tomography (CBCT) Hepatic Arteriography in Chemoembolization for Hepatocellular Carcinoma: Performance Depicting Tumors and Tumor Feeders

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Joon [National Cancer Center, Department of Radiology (Korea, Republic of); Chung, Jin Wook, E-mail: chungjw@snu.ac.kr; Yin, Yong Hu; Kim, Hyo-Cheol; Kim, Young Il; Jae, Hwan Jun; Park, Jae Hyung [Seoul National University College of Medicine, Seoul National University Hospital, Department of Radiology (Korea, Republic of)

    2015-10-15

    PurposeThis study was designed to analyze retrospectively the performance of cone-beam computed tomography (CBCT) hepatic arteriography in depicting tumors and their feeders and to investigate the related determining factors in chemoembolization for hepatocellular carcinoma (HCC).MethodsEighty-six patients with 142 tumors satisfying the imaging diagnosis criteria of HCC were included in this study. The performance of CBCT hepatic arteriography for chemoembolization per tumor and per patient was evaluated using maximum intensity projection images alone (MIP analysis) or MIP combined with multiplanar reformation images (MIP + MPR analysis) regarding the following three aspects: tumor depiction, confidence of tumor feeder detection, and trackability of tumor feeders. Tumor size, tumor enhancement, tumor location, number of feeders, diaphragmatic motion, portal vein enhancement, and hepatic artery to parenchyma enhancement ratio were regarded as potential determining factors.ResultsTumors were depicted in 125 (88.0 %) and 142 tumors (100 %) on MIP and MIP + MPR analysis, respectively. Imaging performances on MIP and MIP + MPR analysis were good enough to perform subsegmental chemoembolization without additional angiographic investigation in 88 (62.0 %) and 128 tumors (90.1 %) on per-tumor basis and in 43 (50 %) and 73 (84.9 %) on per-patient basis, respectively. Significant determining factors for performance in MIP + MPR analysis on per tumor basis were tumor size (p = 0.030), tumor enhancement (0.005), tumor location (p = 0.001), and diaphragmatic motion (p < 0.001).ConclusionsCBCT hepatic arteriography provided sufficient information for subsegmental chemoembolization by depicting tumors and their feeders in the vast majority of patients. Combined analysis of MIP and MPR images was essential to enhance the performance of CBCT hepatic arteriography.

  19. Observation of the anterior loop and mental foramen of the mandibular canal using cone beam computed tomography

    International Nuclear Information System (INIS)

    To evaluate the anteroposterior length and buccal angle of the anterior loop, and the size and location of the mental foramen using cone beam computed tomography (CBCT). 100 CBCT images from 87 adults (43 males and 44 females) ranging in age from 20 to 73 years (average 50 years) with edentulous ridge of the mandibular premolar region were obtained. Axial, sagittal, coronal images were reconstructed from Dental and Block Images of CBCT. The anteroposterior length, shape and buccal angle of the anterior loop, and the size and location of the mental foramen were calculated from reconstructed images of axial, sagittal and coronal CBCT. The anteroposterior length and buccal angle of the mental canal was 4.0 ± 1.2 mm, 37.8 ± 11.6 .deg. C respectively. The loop type with straight course was the most common shape of the mental canal. The location of the mental foramen below the apex of the lower second premolar (78%) was the most common. The maximum size of the mental foramen was 4.6 ± 1.0 mm in width and 3.0 ± 0.6 mm in height. The inner size of the mental canal was 2.6 ± 0.6 mm in width and 2.1 mm ± 0.4 mm in height. CBCT is useful to evaluate the anterior loop and mental foramen of the mandibular canal. Safe guideline of 4 mm from the most anterior point of the mental foramen is recommended for implant and surgical treatment.

  20. Association Between the Lateral Wall Thickness of the Maxillary Sinus and the Dental Status: Cone Beam Computed Tomography Evaluation

    International Nuclear Information System (INIS)

    Assessment of the lateral wall thickness of the maxillary sinus is very important in decision making for many surgical interventions. The association between the thickness of the lateral wall of the maxillary sinus and the dental status is not well identified. To compare the thickness of the lateral wall of the maxillary sinus in individuals with and without teeth to determine if extraction of the teeth can lead to a significant reduction in the thickness of the maxillary sinus lateral wall or not. In a retrospective study on fifty patients with an edentulous space, the thickness of the lateral wall of the maxillary sinus,one centimeter above the sinus floor in the second premolar (P2), first molar (M1) and second molar (M2) areas was determined by cone beam computed tomography scans(CBCTs) and a digital ruler in Romexis F software (Planmeca Romexis 2.4.2.R) and it was compared with values measured in fifty dentated individuals. Three way analysis of variance was applied for comparison after confirmation of the normal distribution of data. The mean of the wall thickness in each of these points was lower in patients with edentulous spaces; however it was not significant. There was no association between gender and the thickness of the lateral wall of the maxillary sinus, but location was associated with different thicknesses. The differences in the thickness based on the location and dental status necessitates assessment of the wall thickness of the maxillary sinus in addition to the current evaluation of bone thickness between the sinus floor and the edentulous crest before maxillary sinus surgery

  1. A comparative study of cone-beam computed tomography and digital periapical radiography in detecting mandibular molars root perforations

    International Nuclear Information System (INIS)

    The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface (root perforation). Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

  2. Evaluation of subjective image quality in relation to diagnostic task for cone beam computed tomography with different fields of view

    International Nuclear Information System (INIS)

    Aims: To evaluate subjective image quality for two diagnostic tasks, periapical diagnosis and implant planning, for cone beam computed tomography (CBCT) using different exposure parameters and fields of view (FOVs). Materials and methods: Examinations were performed in posterior part of the jaws on a skull phantom with 3D Accuitomo (FOV 3 cm x 4 cm) and 3D Accuitomo FPD (FOVs 4 cm x 4 cm and 6 cm x 6 cm). All combinations of 60, 65, 70, 75, 80 kV and 2, 4, 6, 8, 10 mA with a rotation of 180o and 360o were used. Dose-area product (DAP) value was determined for each combination. The images were presented, displaying the object in axial, cross-sectional and sagittal views, without scanning data in a random order for each FOV and jaw. Seven observers assessed image quality on a six-point rating scale. Results: Intra-observer agreement was good (κw = 0.76) and inter-observer agreement moderate (κw = 0.52). Stepwise logistic regression showed kV, mA and diagnostic task to be the most important variables. Periapical diagnosis, regardless jaw, required higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Overall ranking of FOVs gave 4 cm x 4 cm, 6 cm x 6 cm followed by 3 cm x 4 cm. Conclusions: This study has shown that exposure parameters should be adjusted according to diagnostic task. For this particular CBCT brand a rotation of 180o gave good subjective image quality, hence a substantial dose reduction can be achieved without loss of diagnostic information.

  3. Evaluation of subjective image quality in relation to diagnostic task for cone beam computed tomography with different fields of view

    Energy Technology Data Exchange (ETDEWEB)

    Lofthag-Hansen, Sara, E-mail: sara.lofthag-hansen@vgregion.se [Department of Oral and Maxillofacial Radiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden); Clinic of Oral and Maxillofacial Radiology, Public Dental Health, Gothenburg (Sweden); Thilander-Klang, Anne, E-mail: anne.thilander-klang@vgregion.se [Department of Radiation Physics, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden); Groendahl, Kerstin, E-mail: kerstin.grondahl@lj.se [Department of Oral and Maxillofacial Radiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg (Sweden); Department of Oral and Maxillofacial Radiology, The Institute for Postgraduate Dental Education, Joenkoeping (Sweden)

    2011-11-15

    Aims: To evaluate subjective image quality for two diagnostic tasks, periapical diagnosis and implant planning, for cone beam computed tomography (CBCT) using different exposure parameters and fields of view (FOVs). Materials and methods: Examinations were performed in posterior part of the jaws on a skull phantom with 3D Accuitomo (FOV 3 cm x 4 cm) and 3D Accuitomo FPD (FOVs 4 cm x 4 cm and 6 cm x 6 cm). All combinations of 60, 65, 70, 75, 80 kV and 2, 4, 6, 8, 10 mA with a rotation of 180{sup o} and 360{sup o} were used. Dose-area product (DAP) value was determined for each combination. The images were presented, displaying the object in axial, cross-sectional and sagittal views, without scanning data in a random order for each FOV and jaw. Seven observers assessed image quality on a six-point rating scale. Results: Intra-observer agreement was good ({kappa}{sub w} = 0.76) and inter-observer agreement moderate ({kappa}{sub w} = 0.52). Stepwise logistic regression showed kV, mA and diagnostic task to be the most important variables. Periapical diagnosis, regardless jaw, required higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Overall ranking of FOVs gave 4 cm x 4 cm, 6 cm x 6 cm followed by 3 cm x 4 cm. Conclusions: This study has shown that exposure parameters should be adjusted according to diagnostic task. For this particular CBCT brand a rotation of 180{sup o} gave good subjective image quality, hence a substantial dose reduction can be achieved without loss of diagnostic information.

  4. Trabecular bone structure parameters from 3D image processing of clinical multi-slice and cone-beam computed tomography data

    Energy Technology Data Exchange (ETDEWEB)

    Klintstroem, Eva; Smedby, Oerjan [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); UHL County Council of Oestergoetland, Department of Radiology, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Moreno, Rodrigo [Linkoeping University, Center for Medical Image Science and Visualization (CMIV), Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences (IMH)/Radiology, Linkoeping (Sweden); Brismar, Torkel B. [KUS Huddinge, Department of Clinical Science, Intervention and Technology at Karolinska Institutet and Department of Radiology, Stockholm (Sweden)

    2014-02-15

    Bone strength depends on both mineral content and bone structure. The aim of this in vitro study was to develop a method of quantitatively assessing trabecular bone structure by applying three-dimensional image processing to data acquired with multi-slice and cone-beam computed tomography using micro-computed tomography as a reference. Fifteen bone samples from the radius were examined. After segmentation, quantitative measures of bone volume, trabecular thickness, trabecular separation, trabecular number, trabecular nodes, and trabecular termini were obtained. The clinical machines overestimated bone volume and trabecular thickness and underestimated trabecular nodes and number, but cone-beam CT to a lesser extent. Parameters obtained from cone beam CT were strongly correlated with μCT, with correlation coefficients between 0.93 and 0.98 for all parameters except trabecular termini. The high correlation between cone-beam CT and micro-CT suggest the possibility of quantifying and monitoring changes of trabecular bone microarchitecture in vivo using cone beam CT. (orig.)

  5. A quality assurance framework for the fully automated and objective evaluation of image quality in cone-beam computed tomography

    International Nuclear Information System (INIS)

    Purpose: Thousands of cone-beam computed tomography (CBCT) scanners for vascular, maxillofacial, neurological, and body imaging are in clinical use today, but there is no consensus on uniform acceptance and constancy testing for image quality (IQ) and dose yet. The authors developed a quality assurance (QA) framework for fully automated and time-efficient performance evaluation of these systems. In addition, the dependence of objective Fourier-based IQ metrics on direction and position in 3D volumes was investigated for CBCT. Methods: The authors designed a dedicated QA phantom 10 cm in length consisting of five compartments, each with a diameter of 10 cm, and an optional extension ring 16 cm in diameter. A homogeneous section of water-equivalent material allows measuring CT value accuracy, image noise and uniformity, and multidimensional global and local noise power spectra (NPS). For the quantitative determination of 3D high-contrast spatial resolution, the modulation transfer function (MTF) of centrally and peripherally positioned aluminum spheres was computed from edge profiles. Additional in-plane and axial resolution patterns were used to assess resolution qualitatively. The characterization of low-contrast detectability as well as CT value linearity and artifact behavior was tested by utilizing sections with soft-tissue-equivalent and metallic inserts. For an automated QA procedure, a phantom detection algorithm was implemented. All tests used in the dedicated QA program were initially verified in simulation studies and experimentally confirmed on a clinical dental CBCT system. Results: The automated IQ evaluation of volume data sets of the dental CBCT system was achieved with the proposed phantom requiring only one scan for the determination of all desired parameters. Typically, less than 5 min were needed for phantom set-up, scanning, and data analysis. Quantitative evaluation of system performance over time by comparison to previous examinations was also

  6. Three-dimensional cone-beam computed tomography-based virtual treatment planning and fabrication of a surgical splint for asymmetric patients: surgery first approach.

    Science.gov (United States)

    Uribe, Flavio; Janakiraman, Nandakumar; Shafer, David; Nanda, Ravindra

    2013-11-01

    Virtual 3-dimensional planning in orthognathic surgery allows for a detailed visualization and analysis of skeletal and dental deformities, especially in patients with asymmetries. This approach also eliminates conventional stone model surgery through computer-aided fabrication of surgical stents. This article presents a new approach with 3-dimensional cone-beam computed tomography-based treatment planning for the surgical correction of facial asymmetry in conjunction with the surgery first approach. Good esthetic and occlusal outcomes were obtained for 2 patients after orthognathic surgery and orthodontic treatment with a short total treatment time. PMID:24182591

  7. Quantitative Computed Tomography

    OpenAIRE

    Balda, Michael

    2011-01-01

    Computed Tomography (CT) is a wide-spread medical imaging modality. Traditional CT yields information on a patient's anatomy in form of slice images or volume data. Hounsfield Units (HU) are used to quantify the imaged tissue properties. Due to the polychromatic nature of X-rays in CT, the HU values for a specific tissue depend on its density and composition but also on CT system parameters and settings and the surrounding materials. The main objective of Quantitative CT (QCT) is measuring ch...

  8. Stored Luminescence Computed Tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Ge

    2013-01-01

    The phosphor nanoparticles made of doped semiconductors, pre-excited by well-collimated X-ray radiation, were recently reported for their light emission upon NIR light stimulation. The characteristics of X-ray energy storage and NIR stimulated emission is highly desirable to design targeting probes and improve molecular and cellular imaging. Here we propose stored luminescence computed tomography (SLCT), perform realistic numerical simulation, and demonstrate a much-improved spatial resolution in a preclinical research context. The future opportunities are also discussed along this direction.

  9. Computed tomography device

    International Nuclear Information System (INIS)

    A computed tomography device comprising a subtraction unit which obtains differential data strings representing the difference between each time-serial projection data string of a group of projection data strings corresponding to a prospective reconstruction image generated by projection data strings acquired by a data acquisition system, a convolution unit which convolves each time-serial projection data string of the group of projection data strings corresponding to the prospective reconstruction image, and a back-projection unit which back-projects the convolved data strings

  10. Prediction of lung density changes after radiotherapy by cone beam computed tomography response markers and pre-treatment factors for non-small cell lung cancer patients

    DEFF Research Database (Denmark)

    Bernchou, Uffe; Hansen, Olfred; Schytte, Tine; Bertelsen, Anders; Hope, Andrew; Moseley, Douglas; Brink, Carsten

    2015-01-01

    BACKGROUND AND PURPOSE: This study investigates the ability of pre-treatment factors and response markers extracted from standard cone-beam computed tomography (CBCT) images to predict the lung density changes induced by radiotherapy for non-small cell lung cancer (NSCLC) patients. METHODS AND...... MATERIALS: Density changes in follow-up computed tomography scans were evaluated for 135 NSCLC patients treated with radiotherapy. Early response markers were obtained by analysing changes in lung density in CBCT images acquired during the treatment course. The ability of pre-treatment factors and CBCT...... markers to predict lung density changes induced by radiotherapy was investigated. RESULTS: Age and CBCT markers extracted at 10th, 20th, and 30th treatment fraction significantly predicted lung density changes in a multivariable analysis, and a set of response models based on these parameters were...

  11. Detection of the posterior superior alveolar artery in the lateral sinus wall using computed tomography/cone beam computed tomography: a prevalence meta-analysis study and systematic review.

    Science.gov (United States)

    Varela-Centelles, P; Loira-Gago, M; Seoane-Romero, J M; Takkouche, B; Monteiro, L; Seoane, J

    2015-11-01

    A systematic search of MEDLINE, Embase, and Proceedings Web of Science was undertaken to assess the prevalence of the posterior superior alveolar artery (PSAA) in the lateral sinus wall in sinus lift patients, as identified using computed tomography (CT)/cone beam computed tomography (CBCT). For inclusion, the article had to report PSAA detection in the bony wall using CT and/or CBCT in patients with subsinus edentulism. Studies on post-mortem findings, mixed samples (living and cadaveric), those presenting pooled results only, or studies performed for a sinus pathology were excluded. Heterogeneity was checked using an adapted version of the DerSimonian and Laird Q test, and quantified by calculating the proportion of the total variance due to between-study variance (Ri statistic). Eight hundred and eleven single papers were reviewed and filtered according to the inclusion/exclusion criteria. Ten studies were selected (1647 patients and 2740 maxillary sinuses (study unit)). The pooled prevalence of PSAA was 62.02 (95% confidence interval (CI) 46.33-77.71). CBCT studies detected PSAA more frequently (78.12, 95% CI 61.25-94.98) than CT studies (51.19, 95% CI 42.33-60.05). Conventional CT revealed thicker arteries than CBCT. It is concluded that PSAA detection is more frequent when CBCT explorations are used. Additional comparative studies controlling for potential confounding factors are needed to ascertain the actual diagnostic value of radiographic explorations for assessing the PSAA prior to sinus floor elevation procedures. PMID:26215383

  12. Computed tomography of electronics

    Science.gov (United States)

    Bossi, Richard H.; Kruse, Robert J.; Knutson, Benjamin W.

    1989-12-01

    The application of Computed Tomography (CT) and laminography was tested on a variety of electronic components. The effort was performed as a preliminary testing task assignment in the Advanced Development of X ray Computed Tomography Application program. A key area for testing was printed circuit boards for the inspection of solder bonds and in particular for leadless chip carrier devices. During the course of the task assignment several other categories of electronic devices were examined including transformers, connectors, switches from solution and contrast sensitivity phantoms developed for the programs were used to establish quantitative measures of capability used to generate images. This preliminary testing of electronics lead to the conclusion that higher resolution CT scanning is needed to resolve details of interest. CT testing on commercially available system could resolve high contrast details in the range of 2 to 4 lp/mm; however, in many electronic components finer resolution is needed to detect microcracking, voiding and other features. Further testing on high resolution system is recommended. Two areas of immediate potential economic payback for electronics inspection were identified; the inspection of high volume printed circuit board production using high speed laminography and nondestructive failure analysis studies components using high-resolution CT.

  13. Dosimetric Evaluation Between Megavoltage Cone-Beam Computed Tomography and Body Mass Index for Intracranial, Thoracic, and Pelvic Localization

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate radiation dose for organs at risk (OAR) within the cranium, thorax, and pelvis from megavoltage cone-beam computed tomography (MV-CBCT). Using a clinical treatment planning system, CBCT doses were calculated from 60 patient datasets using 27.4 x 27.4 cm2 field size and 200o arc length. The body mass indices (BMIs) for these patients range from 17.2-48.4 kg/m2. A total of 60 CBCT plans were created and calculated with heterogeneity corrections, with monitor units (MU) that varied from 8, 4, and 2 MU per plan. The isocenters of these plans were placed at defined anatomical structures. The maximum dose, dose to the isocenter, and mean dose to the selected critical organs were analyzed. The study found that maximum and isocenter doses were weakly associated with BMI, but linearly associated with the total MU. Average maximum/isocenter doses in the cranium were 10.0 (± 0.18)/7.0 (± 0.08) cGy, 5.0 (± 0.09)/3.5 (± 0.05) cGy, and 2.5 (± .04)/1.8 (± 0.05) cGy for 8, 4, and 2 MU, respectively. Similar trends but slightly larger maximum/isocenter doses were found in the thoracic and pelvic regions. For the cranial region, the average mean doses with a total of 8 MU to the eye, lens, and brain were 9.7 (± 0.12) cGy, 9.1 (± 0.16) cGy, and 7.2 (± 0.10) cGy, respectively. For the thoracic region, the average mean doses to the lung, heart, and spinal cord were 6.6 (± 0.05) cGy, 6.9 (± 1.2) cGy, and 4.7 (± 0.8) cGy, respectively. For the pelvic region, the average mean dose to the femoral heads was 6.4 (± 1.1) cGy. The MV-CBCT doses were linearly associated with the total MU but weakly dependent on patients' BMIs. Daily MV-CBCT has a cumulative effect on the total body dose and critical organs, which should be carefully considered for clinical impacts.

  14. Personalized Assessment of kV Cone Beam Computed Tomography Doses in Image-guided Radiotherapy of Pediatric Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yibao [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Yan Yulong [Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas (United States); Nath, Ravinder [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States); Bao Shanglian [Beijing Key Lab of Medical Physics and Engineering, Peking University, Beijing (China); Deng Jun, E-mail: jun.deng@yale.edu [Department of Therapeutic Radiology, Yale University, New Haven, Connecticut (United States)

    2012-08-01

    Purpose: To develop a quantitative method for the estimation of kV cone beam computed tomography (kVCBCT) doses in pediatric patients undergoing image-guided radiotherapy. Methods and Materials: Forty-two children were retrospectively analyzed in subgroups of different scanned regions: one group in the head-and-neck and the other group in the pelvis. Critical structures in planning CT images were delineated on an Eclipse treatment planning system before being converted into CT phantoms for Monte Carlo simulations. A benchmarked EGS4 Monte Carlo code was used to calculate three-dimensional dose distributions of kVCBCT scans with full-fan high-quality head or half-fan pelvis protocols predefined by the manufacturer. Based on planning CT images and structures exported in DICOM RT format, occipital-frontal circumferences (OFC) were calculated for head-and-neck patients using DICOMan software. Similarly, hip circumferences (HIP) were acquired for the pelvic group. Correlations between mean organ doses and age, weight, OFC, and HIP values were analyzed with SigmaPlot software suite, where regression performances were analyzed with relative dose differences (RDD) and coefficients of determination (R{sup 2}). Results: kVCBCT-contributed mean doses to all critical structures decreased monotonically with studied parameters, with a steeper decrease in the pelvis than in the head. Empirical functions have been developed for a dose estimation of the major organs at risk in the head and pelvis, respectively. If evaluated with physical parameters other than age, a mean RDD of up to 7.9% was observed for all the structures in our population of 42 patients. Conclusions: kVCBCT doses are highly correlated with patient size. According to this study, weight can be used as a primary index for dose assessment in both head and pelvis scans, while OFC and HIP may serve as secondary indices for dose estimation in corresponding regions. With the proposed empirical functions, it is possible

  15. Volumetric Measurement of Root Resorption following Molar Mini-Screw Implant Intrusion Using Cone Beam Computed Tomography

    Science.gov (United States)

    Li, Wen; Chen, Fei; Zhang, Feng; Ding, Wanghui; Ye, Qingsong; Shi, Jiejun; Fu, Baiping

    2013-01-01

    Objective Molar intrusion by mini-screw implantation can cause different degrees of root resorption. However, most methods (2-D and 3-D) used for evaluating root resorption have focused on the root length without considering 3-D resorption. The purpose of this study was to volumetrically evaluate root resorption using cone beam computed tomography(CBCT) after mini-screw implant intrusion. Materials and Methods 1. The volumes of 32 teeth were measured using CBCT and laser scanning to verify the accuracy of CBCT. 2. Twelve overerupted molars from adult patients were investigated in this study. After mini-screw implants were inserted into the buccal and palatal alveolar bones, 150 g of force was applied to the mini-screw implants on each side to intrude the molars. CBCT images of all patients were taken immediately prior to intrusion and after intrusion. The volumes of the roots were calculated using the Mimics software program. The differences between the pre-intrusion and post-intrusion root volumes were statistically evaluated with a paired-samples t-test. In addition, the losses of the roots were statistically compared with each other using one-way analysis of variance at the P0.05). The overerupted molars were significantly intruded (P<0.05), and the average intrusion was 3.30±1.60 mm. The differences between the pre-intrusion and post-intrusion root volumes were statistically significant for all of the roots investigated (P<0.05). The roots were sorted by volume loss in descending order as follows: mesiobuccal, palatal, and distobuccal. Statistical significance was achieved among the three roots. The average total resorption for each tooth was 58.39±1.54 mm3. Conclusion Volume measurement using CBCT was able to effectively evaluate root resorption caused by mini-screw intrusion. The highest volume loss was observed in the mesiobuccal root among the three roots of the investigated first molar teeth. PMID:23585866

  16. Interfractional Position Variation of Pancreatic Tumors Quantified Using Intratumoral Fiducial Markers and Daily Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Horst, Astrid van der, E-mail: a.vanderhorst@amc.uva.nl [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Wognum, Silvia; Dávila Fajardo, Raquel; Jong, Rianne de [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Hooft, Jeanin E. van; Fockens, Paul [Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Tienhoven, Geertjan van; Bel, Arjan [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands)

    2013-09-01

    Purpose: The aim of this study was to quantify interfractional pancreatic position variation using fiducial markers visible on daily cone beam computed tomography (CBCT) scans. In addition, we analyzed possible migration of the markers to investigate their suitability for tumor localization. Methods and Materials: For 13 pancreatic cancer patients with implanted Visicoil markers, CBCT scans were obtained before 17 to 25 fractions (300 CBCTs in total). Image registration with the reference CT was used to determine the displacement of the 2 to 3 markers relative to bony anatomy and to each other. We analyzed the distance between marker pairs as a function of time to identify marker registration error (SD of linear fit residuals) and possible marker migration. For each patient, we determined the mean displacement of markers relative to the reference CT (systematic position error) and the spread in displacements (random position error). From this, we calculated the group systematic error, Σ, and group random error, σ. Results: Marker pair distances showed slight trends with time (range, −0.14 to 0.14 mm/day), possibly due to tissue deformation, but no shifts that would indicate marker migration. The mean SD of the fit residuals was 0.8 mm. We found large interfractional position variations, with for 116 of 300 (39%) fractions a 3-dimensional vector displacement of >10 mm. The spread in displacement varied significantly (P<.01) between patients, from a vector range of 9.1 mm to one of 24.6 mm. For the patient group, Σ was 3.8, 6.6, and 3.5 mm; and σ was 3.6, 4.7 and 2.5 mm, in left–right, superior–inferior, and anterior–posterior directions, respectively. Conclusions: We found large systematic displacements of the fiducial markers relative to bony anatomy, in addition to wide distributions of displacement. These results for interfractional position variation confirm the potential benefit of using fiducial markers rather than bony anatomy for daily online

  17. Interfractional Position Variation of Pancreatic Tumors Quantified Using Intratumoral Fiducial Markers and Daily Cone Beam Computed Tomography

    International Nuclear Information System (INIS)

    Purpose: The aim of this study was to quantify interfractional pancreatic position variation using fiducial markers visible on daily cone beam computed tomography (CBCT) scans. In addition, we analyzed possible migration of the markers to investigate their suitability for tumor localization. Methods and Materials: For 13 pancreatic cancer patients with implanted Visicoil markers, CBCT scans were obtained before 17 to 25 fractions (300 CBCTs in total). Image registration with the reference CT was used to determine the displacement of the 2 to 3 markers relative to bony anatomy and to each other. We analyzed the distance between marker pairs as a function of time to identify marker registration error (SD of linear fit residuals) and possible marker migration. For each patient, we determined the mean displacement of markers relative to the reference CT (systematic position error) and the spread in displacements (random position error). From this, we calculated the group systematic error, Σ, and group random error, σ. Results: Marker pair distances showed slight trends with time (range, −0.14 to 0.14 mm/day), possibly due to tissue deformation, but no shifts that would indicate marker migration. The mean SD of the fit residuals was 0.8 mm. We found large interfractional position variations, with for 116 of 300 (39%) fractions a 3-dimensional vector displacement of >10 mm. The spread in displacement varied significantly (P<.01) between patients, from a vector range of 9.1 mm to one of 24.6 mm. For the patient group, Σ was 3.8, 6.6, and 3.5 mm; and σ was 3.6, 4.7 and 2.5 mm, in left–right, superior–inferior, and anterior–posterior directions, respectively. Conclusions: We found large systematic displacements of the fiducial markers relative to bony anatomy, in addition to wide distributions of displacement. These results for interfractional position variation confirm the potential benefit of using fiducial markers rather than bony anatomy for daily online

  18. Evaluation of anatomy and morphology of human mandibular premolar teeth by cone-beam computed tomography in Iranian population

    Directory of Open Access Journals (Sweden)

    Amin Sobhani Mohhsen

    2013-08-01

    Full Text Available   Background and Aims: Successful root canal therapy requires knowledge of tooth anatomy and root canal morphology. For permanent mandibular premolars, great variety in size, shape and number of roots and root fusion expression has been reported in the literature. There is a wide variety of methods used in studies for evaluating the root canal morphology. One of these methods is Cone-beam Computed tomography (CBCT that reduces the limitations of two-dimensional X-ray imaging, with less exposure in comparison with other 3D radiographies. Thus, this study was designed to evaluate the differences in the root and canal morphology of permanent mandibular premolars in an Iranian population by means of CBCT images.   Materials and Methods: We searched a database of CBCT scans and evaluated 400 (20-60 years old patients who met the inclusion criteria and teeth in this images (CBCT were evaluated in three dimensions (Axial, Coronal and Sagital. Tooth length, number of roots, number of canals, canal type, root curvature and the effect of gender on any of the items mentioned were evaluated. Data were analyzed using T-test.   Results: The average length of the first premolar of mandibular was 22.27 mm and second premolar was 22.28 mm. 98.4% of the first premolar and 98.2% of the second premolar were single root., and 87.3% and 93.1% were single channel. The incidence of number of canals based on vertochy divisions were:type 1: 90.7% and 90.8%, type 0: 2.2% and 2.8%, type 4: 3.3% and 3.1%, type 6: 1.4% and 2.1% and type 3: 2.5% and 1.5% respectively. In any case, there was no significant difference between males and females (P<0.001.   Conclusion: Results indicate that dentists can obtain valuable information about the anatomy and morphology of the root canals using CBCT.

  19. Daily cone-beam computed tomography used to determine tumour shrinkage and localisation in lung cancer patients

    International Nuclear Information System (INIS)

    Purpose/Objective. Daily Cone-beam computed tomography (CBCT) in room imaging is used to determine tumour shrinkage during a full radiotherapy (RT) course. In addition, relative interfractional tumour and lymph node motion is determined for each RT fraction. Material and methods. From November 2009 to March 2010, 20 consecutive lung cancer patients (14 NSCLC, 6 SCLC) were followed with daily CBCT during RT. The gross tumour volume for lung tumour (GTV-t) was visible in all daily CBCT scans and was delineated at the beginning, at the tenth and the 20th fraction, and at the end of treatment. Whenever visible, the gross tumour volume for lymph nodes (GTV-n) was also delineated. The GTV-t and GTV-n volumes were determined. All patients were setup according to an online bony anatomy match. Retrospectively, matching based on the internal target volume (ITV), the GTV-t or the GTV-n was performed. Results. In eight patients, we observed a significant GTV-t shrinkage (15-40%) from the planning CT until the last CBCT. Only five patients presented a significant shrinkage (21-37%) in the GTV-n. Using the daily CBCT imaging, it was found that the mean value of the difference between a setup using the skin tattoo and an online matching using the ITV was 7.3±2.9 mm (3D vector in the direction of ITV). The mean difference between the ITV and bony anatomy matching was 3.0±1.3 mm. Finally, the mean distance between the GTV-t and the GTV-N was 2.9±1.6 mm. Conclusion. One third of all patients with lung cancer undergoing chemo-RT achieved significant tumour shrinkage from planning CT until the end of the radiotherapy. Differences in GTV-t and GTV-n motion was observed and matching using the ITV including both GTV-t and GTV-n is therefore preferable.

  20. Personalized Assessment of kV Cone Beam Computed Tomography Doses in Image-guided Radiotherapy of Pediatric Cancer Patients

    International Nuclear Information System (INIS)

    Purpose: To develop a quantitative method for the estimation of kV cone beam computed tomography (kVCBCT) doses in pediatric patients undergoing image-guided radiotherapy. Methods and Materials: Forty-two children were retrospectively analyzed in subgroups of different scanned regions: one group in the head-and-neck and the other group in the pelvis. Critical structures in planning CT images were delineated on an Eclipse treatment planning system before being converted into CT phantoms for Monte Carlo simulations. A benchmarked EGS4 Monte Carlo code was used to calculate three-dimensional dose distributions of kVCBCT scans with full-fan high-quality head or half-fan pelvis protocols predefined by the manufacturer. Based on planning CT images and structures exported in DICOM RT format, occipital-frontal circumferences (OFC) were calculated for head-and-neck patients using DICOMan software. Similarly, hip circumferences (HIP) were acquired for the pelvic group. Correlations between mean organ doses and age, weight, OFC, and HIP values were analyzed with SigmaPlot software suite, where regression performances were analyzed with relative dose differences (RDD) and coefficients of determination (R2). Results: kVCBCT-contributed mean doses to all critical structures decreased monotonically with studied parameters, with a steeper decrease in the pelvis than in the head. Empirical functions have been developed for a dose estimation of the major organs at risk in the head and pelvis, respectively. If evaluated with physical parameters other than age, a mean RDD of up to 7.9% was observed for all the structures in our population of 42 patients. Conclusions: kVCBCT doses are highly correlated with patient size. According to this study, weight can be used as a primary index for dose assessment in both head and pelvis scans, while OFC and HIP may serve as secondary indices for dose estimation in corresponding regions. With the proposed empirical functions, it is possible to

  1. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution : A cardiac phantom study

    NARCIS (Netherlands)

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-01-01

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative me

  2. A practical fan-beam design and reconstruction algorithm for Active and Passive Computed Tomography of radioactive waste barrels

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Tushar, E-mail: tushar@barc.gov.in; More, M.R.; Ratheesh, Jilju; Sinha, Amar

    2015-09-11

    Active and Passive CT (A&PCT) of waste barrels is mostly carried out in parallel beam configuration due to its relative ease of implementation. This necessitates either using a single detector–source pair and translating the barrel or using multiple detector–source pairs for increasing the scanning speed. Additionally, because the use of bulky HPGe detectors may limit the number of detectors used in both active and passive modes, we propose to use 1″×1″ LaBr{sub 3}(Ce) scintillators. This paper describes a practical fan-beam reconstruction for A&PCT imaging of waste barrels. A fan beam system model has been computed analytically and reconstruction done using MLEM algorithm. The results are compared with analytical reconstruction. - Highlights: • Fan beam geometry with equally spaced detectors implemented for A&PCT. • Analytical computation of system matrix for fan beam geometry. • Implementation of fan beam with single active source in A&PCT.

  3. The validity of cone-beam computed tomography in measuring root canal length using a gold standard

    NARCIS (Netherlands)

    Y.H. Liang; L. Jiang; C. Chen; X.J. Gao; P.R. Wesselink; M.K. Wu; H. Shemesh

    2013-01-01

    Introduction The distance between a coronal reference point and the major apical foramen is important for working length determination. The aim of this in vitro study was to determine the accuracy of root canal length measurements performed with cone-beam computed tomographic (CBCT) scans using a go

  4. Design of a digital beam attenuation system for computed tomography. Part II. Performance study and initial results

    International Nuclear Information System (INIS)

    reduction of ≈4 times relative to flat field CT. The dynamic range for the DBA prototype was 3.7 compared to 84.2 for the flat field scan. Conclusions: Based on the results presented in this paper and the companion paper [T. Szczykutowicz and C. Mistretta, “Design of a digital beam attenuation system for computed tomography. Part I. System design and simulation framework,” Med. Phys. 40, 021905 (2013)], FFMCT implemented via the DBA device seems feasible and should result in both a dose reduction and an improvement in image quality as judged by noise uniformity and scatter reduction. In addition, the dynamic range reduction achievable using the DBA may allow photon counting imaging to become a clinical reality. This study may allow for yet another step to be taken in the field of patient specific dose modulation.

  5. Computed tomography in neurocysticercosis

    International Nuclear Information System (INIS)

    Three hundred and fifty seven computed tomography (CT) from 100 different patients with neurocysticercosis (NC) were studied between 1979 and 1988. All patients were treated with praziquantel (PZQ). A new classification attempting to recognize the CT evolution profile in NC as well as assigning a possible link between CT findings and biological conditions of cysts is evaluated. It was possible to conclude that: intact cysts remain unchanged in consecutive CTs by 11 months and exhibit signs of degeneration in about 18 months after PZQ drug therapy; degenerating cysts can be detected by 10.5 months, disappear in 11 months and become nodular calcifications in about 25 months. Therefore, a time period of at least 36 months can be estimated for the complete evolution profile of cysts in the brain parenchyma. (author)

  6. Long-term stability of the Hounsfield unit to electron density calibration curve in cone-beam computed tomography images for adaptive radiotherapy treatment planning

    OpenAIRE

    Takemura, Akihiro; Tanabe, Shogo; Tokai, Mei; Ueda, Shinichi; Noto, Kimiya; Isomura, Naoki; Kojima, Hironori

    2015-01-01

    Aim To use cone-beam computed tomography (CBCT) images for treatment planning, the Hounsfield unit (HU)-electron density (ED) calibration table for CBCT should be stable. The purpose of this study was to verify the stability of the HU values for the CBCT system over 1 year and to evaluate the effects of variation in HU-ED calibration curves on dose calculation. Materials and Methods A tissue characterisation phantom was scanned with the field of view (FOV) of size S (FOV-S) and FOV of size M ...

  7. Multislice computed tomography coronary angiography

    OpenAIRE

    Cademartiri, Filippo

    2005-01-01

    markdownabstract__Abstract__ Computed Tomography (CT) imaging is also known as "CAT scanning" (Computed Axial Tomography). Tomography is from the Greek word "tomos" meaning "slice" or "section" and "graphia" meaning "describing". CT was invented in 1972 by British engineer Godfrey Hounsfield of EMI Laboratories, England, and independently by South Mrican born physicist Allan Cormack of Tufts University, Massachusetts.1 • 2 Hounsfield was later awarded the Nobel Peace Prize and honoured with K...

  8. Shadow effects in simulated ultrasound images derived from computed tomography images using a focused beam tracing model

    DEFF Research Database (Denmark)

    Pham, An Hoai; Lundgren, Bo; Stage, Bjarne;

    2012-01-01

    Simulation of ultrasound images based on computed tomography (CT) data has previously been performed with different approaches. Shadow effects are normally pronounced in ultrasound images, so they should be included in the simulation. In this study, a method to capture the shadow effects has been......Focus ultrasound scanner (BK Medical, Herlev, Denmark) equipped with a dedicated research interface giving access to beamformed radio frequency data. CT images were obtained with an Aquilion ONE Toshiba CT scanner (Toshiba Medical Systems Corp., Tochigi, Japan). CT data were mapped from Hounsfield units to...

  9. Computed Tomography Measuring Inside Machines

    Science.gov (United States)

    Wozniak, James F.; Scudder, Henry J.; Anders, Jeffrey E.

    1995-01-01

    Computed tomography applied to obtain approximate measurements of radial distances from centerline of turbopump to leading edges of diffuser vanes in turbopump. Use of computed tomography has significance beyond turbopump application: example of general concept of measuring internal dimensions of assembly of parts without having to perform time-consuming task of taking assembly apart and measuring internal parts on coordinate-measuring machine.

  10. Computed tomography of abdominal trauma

    International Nuclear Information System (INIS)

    Abdominal lesions following an accident or surgical interventions are becoming more frequently indications for investigations by computed tomography. Changes of spleen, liver, kidneys, pancreas, and of the retroperitoneal space are discussed. Advantages of computed tomography compared to other investigative methods are shown. (orig.)

  11. Evaluation of 4-dimensional Computed Tomography to 4-dimensional Cone-Beam Computed Tomography Deformable Image Registration for Lung Cancer Adaptive Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate 2 deformable image registration (DIR) algorithms for the purpose of contour mapping to support image-guided adaptive radiation therapy with 4-dimensional cone-beam CT (4DCBCT). Methods and Materials: One planning 4D fan-beam CT (4DFBCT) and 7 weekly 4DCBCT scans were acquired for 10 locally advanced non-small cell lung cancer patients. The gross tumor volume was delineated by a physician in all 4D images. End-of-inspiration phase planning 4DFBCT was registered to the corresponding phase in weekly 4DCBCT images for day-to-day registrations. For phase-to-phase registration, the end-of-inspiration phase from each 4D image was registered to the end-of-expiration phase. Two DIR algorithms—small deformation inverse consistent linear elastic (SICLE) and Insight Toolkit diffeomorphic demons (DEMONS)—were evaluated. Physician-delineated contours were compared with the warped contours by using the Dice similarity coefficient (DSC), average symmetric distance, and false-positive and false-negative indices. The DIR results are compared with rigid registration of tumor. Results: For day-to-day registrations, the mean DSC was 0.75 ± 0.09 with SICLE, 0.70 ± 0.12 with DEMONS, 0.66 ± 0.12 with rigid-tumor registration, and 0.60 ± 0.14 with rigid-bone registration. Results were comparable to intraobserver variability calculated from phase-to-phase registrations as well as measured interobserver variation for 1 patient. SICLE and DEMONS, when compared with rigid-bone (4.1 mm) and rigid-tumor (3.6 mm) registration, respectively reduced the average symmetric distance to 2.6 and 3.3 mm. On average, SICLE and DEMONS increased the DSC to 0.80 and 0.79, respectively, compared with rigid-tumor (0.78) registrations for 4DCBCT phase-to-phase registrations. Conclusions: Deformable image registration achieved comparable accuracy to reported interobserver delineation variability and higher accuracy than rigid-tumor registration. Deformable image registration

  12. Comparison of periapical radiography with cone beam computed tomography in the diagnosis of vertical root fractures in teeth with metallic post

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2014-01-01

    Full Text Available Aim: To compare the diagnostic accuracy of conventional periapical radiography and cone beam computed tomography (CBCT in detecting vertical root fracture (VRF in tooth with metallic post (MP. Materials and Methods: Twenty endodontically-treated teeth received MPs, artificial fractures were created in 10 teeth, and they were all examined with tomography and radiography. The sample consisted of periapical radiography with post and without post, and tomography with post and without post; each group with five fractured and five non-fractured teeth. The images were evaluated by three dental/maxillofacial radiologists and statistical validations were carried out using receiver operating characteristic (ROC analysis. Results: Sensitivity and specificity of the area under the ROC (Az of tomography with post (Az = 0.953 and without post (Az = 0.956 were significantly higher than those of periapical radiography with post (Az = 0.753 and without post (Az = 0.778. Conclusion: CBCT was more accurate than conventional periapical radiography in detecting VRF.

  13. Common-mask guided image reconstruction (c-MGIR) for enhanced 4D cone-beam computed tomography

    International Nuclear Information System (INIS)

    Compared to 3D cone beam computed tomography (3D CBCT), the image quality of commercially available four-dimensional (4D) CBCT is severely impaired due to the insufficient amount of projection data available for each phase. Since the traditional Feldkamp-Davis-Kress (FDK)-based algorithm is infeasible for reconstructing high quality 4D CBCT images with limited projections, investigators had developed several compress-sensing (CS) based algorithms to improve image quality. The aim of this study is to develop a novel algorithm which can provide better image quality than the FDK and other CS based algorithms with limited projections. We named this algorithm ‘the common mask guided image reconstruction’ (c-MGIR).In c-MGIR, the unknown CBCT volume is mathematically modeled as a combination of phase-specific motion vectors and phase-independent static vectors. The common-mask matrix, which is the key concept behind the c-MGIR algorithm, separates the common static part across all phase images from the possible moving part in each phase image. The moving part and the static part of the volumes were then alternatively updated by solving two sub-minimization problems iteratively. As the novel mathematical transformation allows the static volume and moving volumes to be updated (during each iteration) with global projections and ‘well’ solved static volume respectively, the algorithm was able to reduce the noise and under-sampling artifact (an issue faced by other algorithms) to the maximum extent. To evaluate the performance of our proposed c-MGIR, we utilized imaging data from both numerical phantoms and a lung cancer patient. The qualities of the images reconstructed with c-MGIR were compared with (1) standard FDK algorithm, (2) conventional total variation (CTV) based algorithm, (3) prior image constrained compressed sensing (PICCS) algorithm, and (4) motion-map constrained image reconstruction (MCIR) algorithm, respectively. To improve the efficiency of the

  14. Accuracy Assessment of Three-dimensional Surface Reconstructions of In vivo Teeth from Cone-beam Computed Tomography

    Science.gov (United States)

    Sang, Yan-Hui; Hu, Hong-Cheng; Lu, Song-He; Wu, Yu-Wei; Li, Wei-Ran; Tang, Zhi-Hui

    2016-01-01

    Background: The accuracy of three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) has been particularly important in dentistry, which will affect the effectiveness of diagnosis, treatment plan, and outcome in clinical practice. The aims of this study were to assess the linear, volumetric, and geometric accuracy of 3D reconstructions from CBCT and to investigate the influence of voxel size and CBCT system on the reconstructions results. Methods: Fifty teeth from 18 orthodontic patients were assigned to three groups as NewTom VG 0.15 mm group (NewTom VG; voxel size: 0.15 mm; n = 17), NewTom VG 0.30 mm group (NewTom VG; voxel size: 0.30 mm; n = 16), and VATECH DCTPRO 0.30 mm group (VATECH DCTPRO; voxel size: 0.30 mm; n = 17). The 3D reconstruction models of the teeth were segmented from CBCT data manually using Mimics 18.0 (Materialise Dental, Leuven, Belgium), and the extracted teeth were scanned by 3Shape optical scanner (3Shape A/S, Denmark). Linear and volumetric deviations were separately assessed by comparing the length and volume of the 3D reconstruction model with physical measurement by paired t-test. Geometric deviations were assessed by the root mean square value of the imposed 3D reconstruction and optical models by one-sample t-test. To assess the influence of voxel size and CBCT system on 3D reconstruction, analysis of variance (ANOVA) was used (α = 0.05). Results: The linear, volumetric, and geometric deviations were −0.03 ± 0.48 mm, −5.4 ± 2.8%, and 0.117 ± 0.018 mm for NewTom VG 0.15 mm group; −0.45 ± 0.42 mm, −4.5 ± 3.4%, and 0.116 ± 0.014 mm for NewTom VG 0.30 mm group; and −0.93 ± 0.40 mm, −4.8 ± 5.1%, and 0.194 ± 0.117 mm for VATECH DCTPRO 0.30 mm group, respectively. There were statistically significant differences between groups in terms of linear measurement (P < 0.001), but no significant difference in terms of volumetric measurement (P = 0.774). No statistically significant difference were

  15. Common-mask guided image reconstruction (c-MGIR) for enhanced 4D cone-beam computed tomography

    Science.gov (United States)

    Park, Justin C.; Zhang, Hao; Chen, Yunmei; Fan, Qiyong; Li, Jonathan G.; Liu, Chihray; Lu, Bo

    2015-12-01

    Compared to 3D cone beam computed tomography (3D CBCT), the image quality of commercially available four-dimensional (4D) CBCT is severely impaired due to the insufficient amount of projection data available for each phase. Since the traditional Feldkamp-Davis-Kress (FDK)-based algorithm is infeasible for reconstructing high quality 4D CBCT images with limited projections, investigators had developed several compress-sensing (CS) based algorithms to improve image quality. The aim of this study is to develop a novel algorithm which can provide better image quality than the FDK and other CS based algorithms with limited projections. We named this algorithm ‘the common mask guided image reconstruction’ (c-MGIR). In c-MGIR, the unknown CBCT volume is mathematically modeled as a combination of phase-specific motion vectors and phase-independent static vectors. The common-mask matrix, which is the key concept behind the c-MGIR algorithm, separates the common static part across all phase images from the possible moving part in each phase image. The moving part and the static part of the volumes were then alternatively updated by solving two sub-minimization problems iteratively. As the novel mathematical transformation allows the static volume and moving volumes to be updated (during each iteration) with global projections and ‘well’ solved static volume respectively, the algorithm was able to reduce the noise and under-sampling artifact (an issue faced by other algorithms) to the maximum extent. To evaluate the performance of our proposed c-MGIR, we utilized imaging data from both numerical phantoms and a lung cancer patient. The qualities of the images reconstructed with c-MGIR were compared with (1) standard FDK algorithm, (2) conventional total variation (CTV) based algorithm, (3) prior image constrained compressed sensing (PICCS) algorithm, and (4) motion-map constrained image reconstruction (MCIR) algorithm, respectively. To improve the efficiency of the

  16. Spinal computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sartor, K.

    1980-10-01

    Computed tomography (CT) of the spine and spinal cord is gaining more and more importance as a valuable investigative method in neuroradiology. Performed as a noninvasive procedure, with or without intravenous contrast enhancement, it can be used to diagnose paravertebral soft tissue lesions, constrictive lesions of the bony spinal canal, structure changes of the vertebral column or of individual vertebrae, vascular intraspinal lesions, and intraspinal tumors with abnormally high or abnormally low attenuation values. Performed as an invasive procedure, after intrathecal introduction of metrizamide, spinal CT can in selected cases be used in conjunction with conventional metrizamide myelography as an additional procedure (secondary CT-myelography) or even as initial procedure ( primary CT-myelography), taking advantage of its unique properties, namely to provide a transverse axial image of the spine and related soft tissue structures and to detect even small differences in density. Further improvement of spinal CT, particularly the routine non-invasive demonstration of the intraspinal soft tissues, is to be expected.

  17. Stray light in cone beam optical computed tomography: I. Measurement and reduction strategies with planar diffuse source

    Science.gov (United States)

    Granton, Patrick V.; Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2016-04-01

    Optical cone-beam computed tomographic (CBCT) scanning of 3D radiochromic dosimeters may provide a practical method for 3D dose verification in radiation therapy. However, in cone-beam geometry stray light contaminates the projection images, degrading the accuracy of reconstructed linear attenuation coefficients. Stray light was measured using a beam pass aperture array (BPA) and structured illumination methods. The stray-to-primary ray ratio (SPR) along the central axis was found to be 0.24 for a 5% gelatin hydrogel, representative of radiochromic hydrogels. The scanner was modified by moving the spectral filter from the detector to the source, changing the light’s spatial fluence pattern and lowering the acceptance angle by extending distance between the source and object. These modifications reduced the SPR significantly from 0.24 to 0.06. The accuracy of the reconstructed linear attenuation coefficients for uniform carbon black liquids was compared to independent spectrometer measurements. Reducing the stray light increased the range of accurate transmission readings. In order to evaluate scanner performance for the more challenging application to small field dosimetry, a carbon black finger gel phantom was prepared. Reconstructions of the phantom from CBCT and fan-beam CT scans were compared. The modified source resulted in improved agreement. Subtraction of residual stray light, measured with BPA or structured illumination from each projection further improved agreement. Structured illumination was superior to BPA for measuring stray light for the smaller 1.2 and 0.5 cm diameter phantom fingers. At the costs of doubling the scanner size and tripling the number of scans, CBCT reconstructions of low-scattering hydrogel dosimeters agreed with those of fan-beam CT scans.

  18. Quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Judith E. [Royal Infirmary and University, Manchester (United Kingdom)], E-mail: judith.adams@manchester.ac.uk

    2009-09-15

    Quantitative computed tomography (QCT) was introduced in the mid 1970s. The technique is most commonly applied to 2D slices in the lumbar spine to measure trabecular bone mineral density (BMD; mg/cm{sup 3}). Although not as widely utilized as dual-energy X-ray absortiometry (DXA) QCT has some advantages when studying the skeleton (separate measures of cortical and trabecular BMD; measurement of volumetric, as opposed to 'areal' DXA-BMDa, so not size dependent; geometric and structural parameters obtained which contribute to bone strength). A limitation is that the World Health Organisation (WHO) definition of osteoporosis in terms of bone densitometry (T score -2.5 or below using DXA) is not applicable. QCT can be performed on conventional body CT scanners, or at peripheral sites (radius, tibia) using smaller, less expensive dedicated peripheral CT scanners (pQCT). Although the ionising radiation dose of spinal QCT is higher than for DXA, the dose compares favorably with those of other radiographic procedures (spinal radiographs) performed in patients suspected of having osteoporosis. The radiation dose from peripheral QCT scanners is negligible. Technical developments in CT (spiral multi-detector CT; improved spatial resolution) allow rapid acquisition of 3D volume images which enable QCT to be applied to the clinically important site of the proximal femur, more sophisticated analysis of cortical and trabecular bone, the imaging of trabecular structure and the application of finite element analysis (FEA). Such research studies contribute importantly to the understanding of bone growth and development, the effect of disease and treatment on the skeleton and the biomechanics of bone strength and fracture.

  19. [Computed tomography of the heart

    DEFF Research Database (Denmark)

    Kristensen, T.S.; Kofoed, K.F.; der, Recke P. von;

    2009-01-01

    Noninvasive evaluation of the coronary arteries by multi-detector row computed tomography is a promising new alternative to conventional invasive coronary angiography. This article describes the technical background, methods, limitations and clinical applications and reviews current literature th...

  20. Linearity of patient positioning detection. A phantom study of skin markers, cone beam computed tomography, and 3D ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Ballhausen, Hendrik; Hieber, Sheila; Li, Minglun; Belka, Claus; Reiner, Michael [University Hospital of LMU, Department of Radiation Oncology, Munich (Germany); Parodi, Katia [Ludwig-Maximilian-University, Department of Experimental Physics - Medical Physics, Munich (Germany)

    2015-05-01

    Three-dimensional ultrasound (3D-US) is a modality complementary to kilovoltage cone beam computed tomography (kV-CBCT) and skin markers for patient positioning detection. This study compares the linearity of evaluations based on measurements using a modern 3D-US system (Elekta Clarity {sup registered}; Elekta, Stockholm, Sweden), a kV-CBCT system (Elekta iView {sup registered}), and skin markers. An investigator deliberately displaced a multimodal phantom by up to ± 30 mm along different axes. The following data points were acquired: 27 along the lateral axis, 29 along the longitudinal axis, 27 along the vertical axis, and 27 along the space diagonal. At each of these 110 positions, the displacements according to skin' markers were recorded and scans were performed using both 3D-US and kV-CBCT. Shifts were detected by matching bony anatomy or soft tissue density to a reference planning CT in the case of kV-CBCT and for 3D-US, by matching ultrasound volume data to a reference planning volume. A consensus value was calculated from the average of the four modalities. With respect to this consensus value, the linearity (offset and regression coefficient, i.e., slope), average offset, systematic error, and random error of all four modalities were calculated for each axis. Linearity was similar for all four modalities, with regression coefficients between 0.994 and 1.012, and all offsets below 1 mm. The systematic errors of skin markers and 3D-US were higher than for kV-CBCT, but random errors were similar. In particular, 3D-US demonstrated an average offset of 0.36 mm to the right, 0.08 mm inferiorly, and 0.15 mm anteriorly; the systematic error was 0.36 mm laterally, 0.35 mm longitudinally, and 0.22 mm vertically; the random error was 0.15 mm laterally, 0.30 mm longitudinally, and 0.12 mm vertically. A total of 109 out of 110 (99 %) 3D-US measurements were within 1 mm of the consensus value on either axis. The linearity of 3D-US was no worse than that of skin

  1. Comparative of radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dental imaging

    Directory of Open Access Journals (Sweden)

    Nasrollah Jabbari

    2016-03-01

    Full Text Available Background and Aims: With the increasing use of CT (Computed Tomoghraphy scans in dentistry especially in the implantology, there may be significant increases in the radiation exposure and its risk. During the last year’s ConeBeam Computed Tomoghraphy (CBCT has been introduced as an imaging modality for dentistry. The aim of this review article was to present comprehensive information have been published, regarding the  radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dentistry imaging. Materials and Methods: A review of the literature was carried out in PubMed, Google Scholar, Science Direct and Scopus database using key words (CBCT, MSCT, periapical radiography, radiation dose of dentistry and image quality. These searches were limited to the articles published between the years of 1993 to 2015. Conclusion: In comparison to MSCT, CBCT had a short scanning times and lower radiation dose, but in comparison to periapical radiography, CBCT had higher radiation dose. In contrast, CBCT with flat panel detector had higher spatial resolution to MSCT. The periapical radiography also had a good image contrast and relatively high resolution. Generally, CBCT was suitable for hard tissue imaging and MSCT was preferred for soft tissue imaging.

  2. Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners

    International Nuclear Information System (INIS)

    To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

  3. Comparative study of dobutamine stress electron-beam computed tomography and exercise thallium scintigraphy in the diagnosis of patients with suspected coronary artery disease

    International Nuclear Information System (INIS)

    To evaluate the diagnostic value of dobutamine stress electron-beam computed tomography (EBCT) as compared with exercise stress thallium-201 single-photon emission computed tomography (201Tl-SPECT) for the detection of myocardial ischemia, 10 patients with proven or suspected coronary artery disease underwent both tests. Nine of the 10 patients also underwent coronary angiography. EBCT images were analyzed objectively to evaluate systolic wall thickening and analyzed segmentally to determine the distribution of the coronary arteries. Dobutamine stress EBCT revealed the presence of ischemia in 59 segments, whereas exercise stress 201Tl-SPECT revealed ischemia in 51 segments (agreement=73%). The advantage of dobutamine stress EBCT was demonstrated in the inferior/posterior segments as compared with the results of exercise stress 201Tl-SPECT. The overall sensitivity for detecting ischemic regions supplied by coronary arteries with significant stenosis (diameter stenosis >50%) was 83% for dobutamine stress EBCT and 79% for exercise stress 201Tl-SPECT (p=NS), with specificities of 75% and 82% (p=NS). Thus, dobutamine stress EBCT presents a reasonable alternative to exercise stress 201Tl-SPECT for the objective assessment of patients with suspected coronary artery disease. (author)

  4. Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Matheus L. [Dept. of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Campinas (Brazil); Tosoni, Guilherme M. [Dept. of Oral Diagnosis and Surgery, Araraquara Dental School, Sao Paulo State University, Araraquara (Brazil); Lindsey, David H.; Mendoza, Kristopher; Tetradis, Sotirios; Mallya, Sanjay M. [Section of Oral and Maxillofacial Radiology, School of Dentistry, University of California, Los Angeles (United States)

    2014-12-15

    To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K{sub 2}HPO{sub 4} solutions were measured. The relationship between CT number and K{sub 2}HPO{sub 4} concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. The relationship between K{sub 2}HPO{sub 4} concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

  5. Mathematics in computed tomography and related techniques

    International Nuclear Information System (INIS)

    The mathematical basis of computed tomography (CT) was formulated in 1917 by Radon. His theorem states that the 2-D function f(x,y) can be determined at all points from a complete set of its line integrals. Modern methods of image reconstruction include three approaches: algebraic reconstruction techniques with simultaneous iterative reconstruction or simultaneous algebraic reconstruction; convolution back projection; and the Fourier transform method. There is no one best approach. Because the experimental data do not strictly satisfy theoretical models, a number of effects have to be taken into account; in particular, the problems of beam geometry, finite beam dimensions and distribution, beam scattering, and the radiation source spectrum. Tomography with truncated data is of interest, employing mathematical approximations to compensate for the unmeasured projection data. Mathematical techniques in image processing and data analysis are also extensively used. 13 refs

  6. Comparison of step-and-shoot and continuous scanning methods in cone-beam computed micro-tomography for NDT

    International Nuclear Information System (INIS)

    The purpose of this study is to compare the quality of images obtained from the step-and-shoot and continuous scanning methods in terms of system resolution. In addition, this study aims to determine the fastest continuous scanning speed with image quality enough for the defect inspection. Computed tomography (CT) is an emerging technology for the non-destructive testing (NDT) of high precision manufacturing to enhance the production reliability. In order to use the CT for the NDT, high-speed inspection is essential for a higher production yield. However, conventional high resolution CT systems usually require terms of minutes to take exam because they employ the step-and-shoot protocol to avoid motion blur during the image acquisition. Unlike the step-and-shoot protocol, continuous scan protocol, which simultaneously acquires projection images during the rotation, can only require terms of seconds because it can ignore the time delay between 'stop and go' steps of rotation. Continuous scan is used for medical CT systems. However, the loss of system resolution originated from the motion blur cannot be avoidable. In order to investigate the relationship between acquisition time and image quality of continuous scanning, the experiment will be conducted with varying rotational speed of object

  7. Cone beam computed tomography evaluation and endodontic management of permanent mandibular second molar with four roots: A rare case report and literature review

    Directory of Open Access Journals (Sweden)

    Subhashini Rajasekhara

    2014-01-01

    Full Text Available The morphological variation in the number of roots and root canals, especially in multi-rooted teeth is a constant challenge for diagnosis and successful endodontic therapy. Knowledge of the most common anatomic characteristics and their possible variations is fundamental. Although, endodontic management of four-rooted mandibular first molars have been observed on a few occasions in the literature, to the best of our knowledge four-rooted mandibular second molars having two mesial and two distal roots have not been reported. This paper highlights endodontic management of mandibular second molar with four roots (two mesial and two distal with one canal in each root and its cone beam computed tomography (CBCT evaluation which was primarily done for post treatment assessment for diagnosing post-endodontic complications, at the same time confirmed our radiographic diagnosis of this variation. This also helped us portraying the anatomy of this rare variation.

  8. Relationship among the structure of mandibular alveolar bone, occlusal force, the masseter muscle, and maxillofacial morphology. Evaluation using cone beam computed tomography

    International Nuclear Information System (INIS)

    We elucidated the relationship among the thickness of the mandibular alveolar cortical bone, the thickness of the mandibular alveolar cancellous bone, maxillofacial morphology, occlusal force, and the masseter muscle. The subjects were 18 adult male volunteers with a mean age of 29 years who had normal occlusion. The thickness of the cortical and cancellous bone were measured using a cone beam computed tomography scan. The maxillofacial morphology was observed with lateral cephalograms and the occlusal force was measured with pressure-sensitive film. The volume of the masseter muscle was determined from MRI images and correlations were determined with Student's t-test. We found that subjects with highly developed cortical and cancellous bone have a relatively dolicofacial morphology, while those with poorly developed cortical and cancellous bone have a relatively brachiofacial morphology. The results suggest that masticatory function is related to thickness of the cancellous bone. (author)

  9. Retrospective study of root canal configurations of maxillary third molars in Central India population using cone beam computed tomography Part- I

    Science.gov (United States)

    Rawtiya, Manjusha; Somasundaram, Pavithra; Wadhwani, Shefali; Munuga, Swapna; Agarwal, Manish; Sethi, Priyank

    2016-01-01

    Objective: The aim of this study was to investigate the root and canal morphology of maxillary third molars in Central India population using cone-beam computed tomography (CBCT) analysis. Materials and Methods: CBCT images of 116 maxillary third molars were observed, and data regarding the number of roots, the number of canals, and Vertucci's Classification in each root was statistically evaluated. Results: Majority of Maxillary third molars had three roots (55.2%) and three canals (37.9%). Most MB root (43.8%), DB root (87.5%), and palatal root (100%) of maxillary third molars had Vertucci Type I. Mesiobuccal root of three-rooted maxillary third molars had Vertucci Type I (43.8%) and Type IV (40.6%) configuration. Overall prevalence of C-shaped canals in maxillary third molars was 3.4%. Conclusion: There was a high prevalence of three-rooted maxillary molars with three canals. PMID:27011747

  10. Cone-Beam Computed Tomography-Guided Management of C-Shaped Type III Dens Invaginatus With Peri-invagination Periodontitis in a Maxillary Canine: A Case Report.

    Science.gov (United States)

    Mittal, Priya; Jadhav, Ganesh R; Syed, Shibli; Bhujbal, Nikita D

    2016-06-01

    Dens invaginatus (DI) is a developmental anomaly seen infrequently in maxillary canines. This article describes cone-beam computed tomography-guided nonsurgical management of type III (subtype B) DI in a permanent maxillary canine associated with a sinus tract and peri-invagination periodontitis in a 17-year-old female. After gaining access to the root canal, thorough chemo-mechanical preparation was performed and usage of intracanal medicament of calcium hydroxide was prescribed for 3 weeks, during which the sinus tract healed completely. Obturation was completed by a technique of down-packing master-cone gutta-percha, followed by backfilling with thermoplasticized gutta-percha. At 12-months follow-up, the patient was asymptomatic with complete resolution of the sinus tract and radiographic evidence of healing of periapical pathology. PMID:27525733

  11. Non-invasive endodontic management of fused mandibular second molar and a paramolar, using cone beam computed tomography as an adjunctive diagnostic aid: A case report

    Directory of Open Access Journals (Sweden)

    Priyanka Ghogre

    2014-01-01

    Full Text Available Tooth fusion is a developmental anomaly characterized by the union between the dentin and/or enamel of at least two separately developing teeth. Fusion is a rare occurrence, with overall prevalence to be approximately 0.5% in deciduous teeth and 0.1% in permanent dentition. The significance of this particular case was that the unilateral fusion occurred in a permanent mandibular second molar with a paramolar and successful endodontic management was done. The rarity with which this entity appears, along with its complex characteristics, often makes it difficult to treat. In this case, a new advanced three-dimensional imaging Cone Beam Computed Tomography (CBCT was used as an adjunctive diagnostic aid to differentiate between fusion occurred before or after root formation and help to reach the correct diagnosis.

  12. A unique functional craniofacial suture that may normally never ossify: A cone-beam computed tomography-based report of two cases.

    Science.gov (United States)

    Poorsattar Bejeh Mir, Karim; Poorsattar Bejeh Mir, Arash; Bejeh Mir, Morvarid Poorsattar; Haghanifar, Sina

    2016-01-01

    The premise of complete ossification of midpalatal suture in early adulthood still has its popularity, though conflicting data are emerging in the literature. A 49-year-old male and a 54-year-old female Iranian patient, both dentulous, were referred to a Maxillofacial Radiology Center to be evaluated for implant insertion. In cone-beam computed tomography (CBCT) evaluation, an in-ossified suture was found in anterior two-third of midpalatal region of both individuals. The application of clinical vignettes from CBCT findings for maxillofacial orthodontic and orthopedic purposes is of value. Existing cases of successful nonsurgical rapid palatal expansion of maxilla in adults could surrogate this dogma about timing for ossification of midpalatal suture which is considered as a purely chronologic-related phenomenon and transmitted masticatory forces may be one possible cause (functional hypothesis). PMID:27134455

  13. Cone Beam Computed Tomography Evaluation of the Periapical Status of Nonvital Tooth with Open Apex Obturated with Mineral Trioxide Aggregate: A Case Report

    Directory of Open Access Journals (Sweden)

    Vijay Shekhar

    2013-01-01

    Full Text Available Management of a tooth with open apex is a challenge to the dental practitioners. Evaluation of the periapical healing is required in such cases by radiographic techniques. The objective of this paper was to assess the healing of a periapical lesion in a non-vital tooth with open apex treated with mineral trioxide aggregate (MTA obturation using cone beam computed tomography (CBCT. The endodontic treatment of a fractured non-vital discolored maxillary left lateral incisor with an open apex was done with MTA obturation. The clinical and radiographic followup done regularly showed that the tooth was clinically asymptomatic and that the size of the periapical lesion observed by intraoral periapical (IOPA radiographs and CBCT was decreased remarkably after two years. CBCT and IOPA radiographs were found to be useful radiographic tools to assess the healing of a large periapical lesion in a non-vital tooth with open apex managed by MTA obturation.

  14. Facial soft-tissue asymmetry in three-dimensional cone-beam computed tomography images of children with surgically corrected unilateral clefts.

    Science.gov (United States)

    Starbuck, John Marlow; Ghoneima, Ahmed; Kula, Katherine

    2014-03-01

    Cleft lip with or without cleft palate (CL/P) is a relatively common craniofacial malformation involving bony and soft-tissue disruptions of the nasolabial and dentoalveolar regions. The combination of CL/P and subsequent craniofacial surgeries to close the cleft and improve appearance of the cutaneous upper lip and nose can cause scarring and muscle pull, possibly resulting in soft-tissue depth asymmetries across the face. We tested the hypothesis that tissue depths in children with unilateral CL/P exhibit differences in symmetry across the sides of the face. Twenty-eight tissue depths were measured on cone-beam computed tomography images of children with unilateral CL/P (n = 55), aged 7 to 17 years, using Dolphin software (version 11.5). Significant differences in tissue depth symmetry were found around the cutaneous upper lip and nose in patients with unilateral CL/P. PMID:24531247

  15. Palatal bone thickness measured by palatal index method using cone-beam computed tomography in nonorthodontic patients for placement of mini-implants

    Directory of Open Access Journals (Sweden)

    W S Manjula

    2015-01-01

    Full Text Available Introduction: The purpose of this study was to compare the bone thickness of the palatal areas in different palatal index (PI groups. Materials and Methods: Cone-beam computed tomography scans of 10 subjects were selected with a mean age group of 18 years. The measurements of palatal bone thickness were made at 36 sites using CareStream 3D Imaging software. The PI was measured using Korkhaus ratio (palatal height/palatal width. One-way analysis of variance was used to analyze intergroup differences, as well as the PI difference. Results: Bone thickness was higher in the anterior region than in the middle and posterior regions P<0.001. Furthermore, significant differences were found among the midline, medial, and lateral areas of the palate. Conclusions: These findings might be helpful for clinicians to enhance the successful use of temporary anchorage devices in the palate.

  16. Evaluation of linear measurements of implant sites based o head orientation during acquisition: An ex vivo study using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sabban, Hanadi; Mahdian, Mina; Dhingra, Ajay; Lurie, Alan G.; Tadinada, Aditya [University of Connecticut School of Dental Medicine, Farmington (United States)

    2015-06-15

    This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension.

  17. What is Computed Tomography?

    Science.gov (United States)

    ... word "tomography" is from the Greek word "tomos" meaning "slice" or "section" and "graphe" meaning "drawing." A CT imaging system produces cross-sectional ... The patient may receive an injection of a "contrast material" to facilitate visualization of vascular structure. Detectors ...

  18. Analysis of the effect of cone-beam geometry and test object configuration on the measurement accuracy of a computed tomography scanner used for dimensional measurement

    Science.gov (United States)

    Kumar, Jagadeesha; Attridge, Alex; Wood, P. K. C.; Williams, Mark A.

    2011-03-01

    Industrial x-ray computed tomography (CT) scanners are used for non-contact dimensional measurement of small, fragile components and difficult-to-access internal features of castings and mouldings. However, the accuracy and repeatability of measurements are influenced by factors such as cone-beam system geometry, test object configuration, x-ray power, material and size of test object, detector characteristics and data analysis methods. An attempt is made in this work to understand the measurement errors of a CT scanner over the complete scan volume, taking into account only the errors in system geometry and the object configuration within the scanner. A cone-beam simulation model is developed with the radiographic image projection and reconstruction steps. A known amount of errors in geometrical parameters were introduced in the model to understand the effect of geometry of the cone-beam CT system on measurement accuracy for different positions, orientations and sizes of the test object. Simulation analysis shows that the geometrical parameters have a significant influence on the dimensional measurement at specific configurations of the test object. Finally, the importance of system alignment and estimation of correct parameters for accurate CT measurements is outlined based on the analysis.

  19. Curved Beam Computed Tomography based Structural Rigidity Analysis of Bones with Simulated Lytic Defect: A Comparative Study with Finite Element Analysis.

    Science.gov (United States)

    Oftadeh, R; Karimi, Z; Villa-Camacho, J; Tanck, E; Verdonschot, N; Goebel, R; Snyder, B D; Hashemi, H N; Vaziri, A; Nazarian, A

    2016-01-01

    In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections. Experimental results were compared to the results obtained from FEA and CTRA. The failure loads predicated by curved beam CTRA and FEA are in agreement with experimental results. The results also show that the proposed method is an efficient and reliable method to find both the location and magnitude of failure load. Moreover, the results show that the proposed curved CTRA outperforms the regular straight beam CTRA, which ignores the bone intrinsic curvature and can be used as a useful tool in clinical practices. PMID:27585495

  20. Neuroanatomy of cranial computed tomography

    International Nuclear Information System (INIS)

    Based on the fundamental structures visualized by means of computed tomography, the authors present the functional systems which are relevant in neurology by means of axial cross-sections. All drawings were prepared from original preparations by means of a new technique which is similar to the grey values of X-ray CT and nuclear magnetic resonance tomography. A detailed description is given of the topics of neurofunctional lesions

  1. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... up in shades of gray, and air appears black. With CT scanning, numerous x-ray beams and ... be removed by the technologist, and the tiny hole made by the needle will be covered with ...

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... up in shades of gray, and air appears black. With CT scanning, numerous x-ray beams and ... be removed by the technologist, and the tiny hole made by the needle will be covered with ...

  3. Computed tomography using synchrotron radiation

    International Nuclear Information System (INIS)

    X-ray computed tomography (CT) is a widely used method of obtaining cross-sectional views of objects. The high intensity, natural collimation, monochromaticity and energy tunability of synchrotron x-ray sources could potentially be used to provide CT images of improved quality. The advantages of these systems would be that images could be produced more rapidly with better spatial resolution and reduced beam artifacts. In addition, images, in some cases, could be acquired with elemental sensitivity. As a demonstration of the capability of such a system, CT images were obtained of four slices of an excised pig heart in which the arteries and the cardiac chambers were filled with an iodinated medium. Images were taken with incident x-rays tuned successively to energies just above and below the iodine K edge. Iodine specific images were obtained by logarithmically subtracting the low energy image data from the high energy data and then reconstructing the image. CT imaging using synchrotron radiation may become a convenient and non-destructive method of imaging samples difficult to study by other methods

  4. Computed tomography in the urological field by means of scanner of fan beam x-ray rotationary

    International Nuclear Information System (INIS)

    Twelve cases of urological patients were observed by computed tomography (Ohio-nuclear's Delta-scan 2020). 5 cases of them were as follows: 1) A 25-year-old female of chronic renal failure, in which both kidneys showed multiple cystic structure, what is called ''acquired cyst of the kidney''. 2) A 28-year-old male of chronic renal failure, in which round calcificated shadow was revealed at the left kidney. It was very difficult to demonstrate the round shadow on KUB. Renal carcinoma was suspected by selective renal arteriography, and the nephrectomy specimen revealed renal cell carcinoma. 3) A 39-year-old male of left renal carcinoma, in which CT of lung showed manifest metastatis, and abdominal slice showed large tumor embolus of left renal vein. 4) A 67-year-old male of bladder tumor at the left lateral wall, in which stalk was not clearly confirmed by a cystoscopic examination. By CT of supine or prone position, the tumor mass inclined downward. This suggested the existence of stalk. Extravesical outline seemed smooth, and so the tumor was suspected to be of low stage. 5) A 71-year-old male of prostatic cancer, in which by RI bone scanning and x-ray examination, the left scapula, ribs, 2nd lumbar vertebra were shown to have metastases. CT of 2nd vertebra revealed patchy high density area. By this scanner, only two seconds per one slice are required. So the artifacts, such as so-called streaking by respiration, movement of intestinal gas, are almost dissoluted. And this fact is very important and useful for many clinical fields, such as alimentary organs and urogenital organs. (author)

  5. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... ring, called a gantry. The computer workstation that processes the imaging information is located in a separate ... follows a spiral path. A special computer program processes this large volume of data to create two- ...

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... ring, called a gantry. The computer workstation that processes the imaging information is located in a separate ... follows a spiral path. A special computer program processes this large volume of data to create two- ...

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  8. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  9. Large Reactional Osteogenesis in Maxillary Sinus Associated with Secondary Root Canal Infection Detected Using Cone-beam Computed Tomography.

    Science.gov (United States)

    Estrela, Carlos; Porto, Olavo César Lyra; Costa, Nádia Lago; Garrote, Marcel da Silva; Decurcio, Daniel Almeida; Bueno, Mike R; Silva, Brunno Santos de Freitas

    2015-12-01

    Inflammatory injuries in the maxillary sinus may originate from root canal infections and lead to bone resorption or regeneration. This report describes the radiographic findings of 4 asymptomatic clinical cases of large reactional osteogenesis in the maxillary sinus (MS) associated with secondary root canal infection detected using cone-beam computed tomographic (CBCT) imaging. Apical periodontitis, a consequence of root canal infection, may lead to a periosteal reaction in the MS and osteogenesis seen as a radiopaque structure on imaging scans. The use of a map-reading strategy for the longitudinal and sequential slices of CBCT images may contribute to the definition of diagnoses and treatment plans. Root canal infections may lead to reactional osteogenesis in the MS. High-resolution CBCT images may reveal changes that go unnoticed when using conventional imaging. Findings may help define initial diagnoses and therapeutic plans, but only histopathology provides a definitive diagnosis. Surgical enucleation of the periapical lesion is recommended if nonsurgical root canal treatment fails to control apical periodontitis. PMID:26478436

  10. Computer tomography in acute pyelonephritis

    Energy Technology Data Exchange (ETDEWEB)

    Triller, J.; Scheidegger, J.; Terrier, F.

    1983-07-01

    Computer tomography of the kidneys was performed on 30 patients with acute renal infections (acute suppurative pyelonephritis, acute renal abscess, infected cyst, pyelonephrosis, calculus perforation, retroperitoneal abscess). Computer tomography provided more accurate information concerning the extent of the renal and extra-renal inflammatory process than did the urogram or sonogram. This may significantly affect the choice of treatment, particularly concerning the use of drugs or of surgery. Angiography and retrograde pyelography may be used in selected cases, especially where there is a suspicion of acute bacterial nephritis, renal vein thrombosis or ureteric obstruction.

  11. The Effect of a Contrast Agent on Proton Beam Range in Radiotherapy Planning Using Computed Tomography for Patients With Locoregionally Advanced Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ui-Jung; Shin, Dong Ho [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of); Kim, Tae Hyun, E-mail: k2onco@naver.com [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of); Moon, Sung Ho; Lim, Young Kyung; Jeong, Hojin; Rah, Jeong-Eun; Kim, Sang Soo; Kim, Joo-Young; Kim, Dae Yong; Park, Sung Yong; Cho, Kwan Ho [Proton Therapy Center, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi (Korea, Republic of)

    2011-11-15

    Purpose: We evaluated the effect of a contrast agent (CA) on proton beam range in a treatment planning system (TPS) for patients with locoregionally advanced lung cancer. Methods and Materials: Two sets of computed tomography (CT) images (with and without CA) were obtained from 20 patients with lung cancer. Because the increase in Hounsfield unit ( Increment HU) value of the heart and great vessels due to the effect of CA is most prominent among thoracic structures, to evaluate the effect of CA on proton beam range in the TPS, we compared the calculated distal ranges in the plan with CA-enhanced CT with those with corrected CT, in which the HU values of the heart and great vessels in the CA-enhanced CT were replaced by average HU values obtained from the unenhanced CT. Results: The mean Increment HU value and the longest length of the heart and great vessels within the proton beam path in the field that passed through these structures were 189 {+-} 29 HU (range, 110-250 HU) and 7.1 {+-} 1.1 cm (range, 2.6-11.2 cm), respectively. The mean distal range error in the TPS because of the presence of CA was 1.0 {+-} 0.7 cm (range, 0.2-2.6 cm). Conclusion: If CA-enhanced CT images are used for radiotherapy planning using a proton beam for the treatment of lung cancer, our results suggest that the HU values of the heart and great vessels should be replaced by the average HU values of soft tissue to avoid discrepancies between planned and delivered doses.

  12. The feasibility of polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects: a Monte Carlo study

    International Nuclear Information System (INIS)

    A recent study investigated the feasibility to develop a bench-top x-ray fluorescence computed tomography (XFCT) system capable of determining the spatial distribution and concentration of gold nanoparticles (GNPs) in vivo using a diagnostic energy range polychromatic (i.e. 110 kVp) pencil-beam source. In this follow-up study, we examined the feasibility of a polychromatic cone-beam implementation of XFCT by Monte Carlo (MC) simulations using the MCNP5 code. In the current MC model, cylindrical columns with various sizes (5-10 mm in diameter) containing water loaded with GNPs (0.1-2% gold by weight) were inserted into a 5 cm diameter cylindrical polymethyl methacrylate phantom. The phantom was then irradiated by a lead-filtered 110 kVp x-ray source, and the resulting gold fluorescence and Compton-scattered photons were collected by a series of energy-sensitive tallies after passing through lead parallel-hole collimators. A maximum-likelihood iterative reconstruction algorithm was implemented to reconstruct the image of GNP-loaded objects within the phantom. The effects of attenuation of both the primary beam through the phantom and the gold fluorescence photons en route to the detector were corrected during the image reconstruction. Accurate images of the GNP-containing phantom were successfully reconstructed for three different phantom configurations, with both spatial distribution and relative concentration of GNPs well identified. The pixel intensity of regions containing GNPs was linearly proportional to the gold concentration. The current MC study strongly suggests the possibility of developing a bench-top, polychromatic, cone-beam XFCT system for in vivo imaging.

  13. The Effect of a Contrast Agent on Proton Beam Range in Radiotherapy Planning Using Computed Tomography for Patients With Locoregionally Advanced Lung Cancer

    International Nuclear Information System (INIS)

    Purpose: We evaluated the effect of a contrast agent (CA) on proton beam range in a treatment planning system (TPS) for patients with locoregionally advanced lung cancer. Methods and Materials: Two sets of computed tomography (CT) images (with and without CA) were obtained from 20 patients with lung cancer. Because the increase in Hounsfield unit (∆HU) value of the heart and great vessels due to the effect of CA is most prominent among thoracic structures, to evaluate the effect of CA on proton beam range in the TPS, we compared the calculated distal ranges in the plan with CA-enhanced CT with those with corrected CT, in which the HU values of the heart and great vessels in the CA-enhanced CT were replaced by average HU values obtained from the unenhanced CT. Results: The mean ∆HU value and the longest length of the heart and great vessels within the proton beam path in the field that passed through these structures were 189 ± 29 HU (range, 110–250 HU) and 7.1 ± 1.1 cm (range, 2.6–11.2 cm), respectively. The mean distal range error in the TPS because of the presence of CA was 1.0 ± 0.7 cm (range, 0.2–2.6 cm). Conclusion: If CA-enhanced CT images are used for radiotherapy planning using a proton beam for the treatment of lung cancer, our results suggest that the HU values of the heart and great vessels should be replaced by the average HU values of soft tissue to avoid discrepancies between planned and delivered doses.

  14. The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors

    International Nuclear Information System (INIS)

    The influence of antiscatter x-ray grids on image quality in cone-beam computed tomography (CT) is evaluated through broad experimental investigation for various anatomical sites (head and body), scatter conditions (scatter-to-primary ratio (SPR) ranging from ∼10% to 150%), patient dose, and spatial resolution in three-dimensional reconstructions. Studies involved linear grids in combination with a flat-panel imager on a system for kilovoltage cone-beam CT imaging and guidance of radiation therapy. Grids were found to be effective in reducing x-ray scatter 'cupping' artifacts, with heavier grids providing increased image uniformity. The system was highly robust against ring artifacts that might arise in CT reconstructions as a result of gridline shadows in the projection data. The influence of grids on soft-tissue detectability was evaluated quantitatively in terms of absolute contrast, voxel noise, and contrast-to-noise ratio (CNR) in cone-beam CT reconstructions of 16 cm 'head' and 32 cm 'body' cylindrical phantoms. Imaging performance was investigated qualitatively in observer preference tests based on patient images (pelvis, abdomen, and head-and-neck sites) acquired with and without antiscatter grids. The results suggest that although grids reduce scatter artifacts and improve subject contrast, there is little strong motivation for the use of grids in cone-beam CT in terms of CNR and overall image quality under most circumstances. The results highlight the tradeoffs in contrast and noise imparted by grids, showing improved image quality with grids only under specific conditions of high x-ray scatter (SPR>100%), high imaging dose (Dcenter>2 cGy), and low spatial resolution (voxel size ≥1 mm)

  15. Comparison of localization performance with implanted fiducial markers and cone-beam computed tomography for on-line image-guided radiotherapy of the prostate

    International Nuclear Information System (INIS)

    Purpose: The aim of this work was to assess the accuracy of kilovoltage (kV) cone-beam computed tomography (CBCT)-based setup corrections as compared with orthogonal megavoltage (MV) portal image-based corrections for patients undergoing external-beam radiotherapy of the prostate. Methods and Materials: Daily cone-beam CT volumetric images were acquired after setup for patients with three intraprostatic fiducial markers. The estimated couch shifts were compared retrospectively to patient adjustments based on two orthogonal MV portal images (the current clinical standard of care in our institution). The CBCT soft-tissue based shifts were also estimated by digitally removing the gold markers in each projection to suppress the artifacts in the reconstructed volumes. A total of 256 volumetric images for 15 patients were analyzed. Results: The Pearson coefficient of correlation for the patient position shifts using fiducial markers in MV vs. kV was (R2 = 0.95, 0.84, 0.81) in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. The correlation using soft-tissue matching was as follows: R2 = 0.90, 0.49, 0.51 in the LR, AP and SI directions. A Bland-Altman analysis showed no significant trends in the data. The percentage of shifts within a ±3-mm tolerance (the clinical action level) was 99.7%, 95.5%, 91.3% for fiducial marker matching and 99.5%, 70.3%, 78.4% for soft-tissue matching. Conclusions: Cone-beam CT is an accurate and precise tool for image guidance. It provides an equivalent means of patient setup correction for prostate patients with implanted gold fiducial markers. Use of the additional information provided by the visualization of soft-tissue structures is an active area of research

  16. Emission computed tomography

    International Nuclear Information System (INIS)

    Although there are many common aspects to x-ray transmission and radionuclide emission (ECT) computerized tomography, there are added difficulties and a number of particular factors which form the basis of ECT. The relationship between the physical factors, system design, methodologic approach and assumptions of ECT is discussed. The instrumentation design and application strategies in ECT at this time are diverse and in a rapid stage of development. The approaches are divided into two major categories of Single Photon Counting (SPC) employing scanner and camera concepts with radionuclides of 99/sup m/Tc, 201Tl, 123I etc., and Annihilation Coincidence Detection (ACD) of positron-emitting radionuclides. Six systems in the former and ten systems in the latter category, with examples of typical studies, illustrate the different approaches

  17. Calcium score of small coronary calcifications on multidetector computed tomography

    DEFF Research Database (Denmark)

    Groen, J M; Kofoed, K F; Zacho, M;

    2013-01-01

    Multi detector computed tomography (MDCT) underestimates the coronary calcium score as compared to electron beam tomography (EBT). Therefore clinical risk stratification based on MDCT calcium scoring may be inaccurate. The aim of this study was to assess the feasibility of a new phantom which...

  18. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... special computer program processes this large volume of data to create two-dimensional cross-sectional images of ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  19. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... special computer program processes this large volume of data to create two-dimensional cross-sectional images of ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  1. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... look like? The CT scanner is typically a large, box-like machine with a hole, or short ... spiral path. A special computer program processes this large volume of data to create two-dimensional cross- ...

  3. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... look like? The CT scanner is typically a large, box-like machine with a hole, or short ... spiral path. A special computer program processes this large volume of data to create two-dimensional cross- ...

  4. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... planes, and can even generate three-dimensional images. These images can be viewed on a computer monitor, ... to reduce the risk of an allergic reaction. These medications generally need to be taken 12 hours ...

  5. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... planes, and can even generate three-dimensional images. These images can be viewed on a computer monitor, ... to reduce the risk of an allergic reaction. These medications generally need to be taken 12 hours ...

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... a gantry. The computer workstation that processes the imaging information is located in a separate control room, ... which are then displayed on a monitor. CT imaging is sometimes compared to looking into a loaf ...

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... a gantry. The computer workstation that processes the imaging information is located in a separate control room, ... which are then displayed on a monitor. CT imaging is sometimes compared to looking into a loaf ...

  8. Unenhanced Cone Beam Computed Tomography and Fusion Imaging in Direct Percutaneous Sac Injection for Treatment of Type II Endoleak: Technical Note

    Energy Technology Data Exchange (ETDEWEB)

    Carrafiello, Gianpaolo, E-mail: gcarraf@gmail.com; Ierardi, Anna Maria [Insubria University, Interventional Radiology, Department of Radiology (Italy); Radaelli, Alessandro [Philips Healthcare (Netherlands); Marchi, Giuseppe De; Floridi, Chiara [Insubria University, Interventional Radiology, Department of Radiology (Italy); Piffaretti, Gabriele [University of Insubria, Vascular Surgery Department (Italy); Federico, Fontana [Insubria University, Interventional Radiology, Department of Radiology (Italy)

    2016-03-15

    AimTo evaluate safety, feasibility, technical success, and clinical success of direct percutaneous sac injection (DPSI) for the treatment of type II endoleaks (T2EL) using anatomical landmarks on cone beam computed tomography (CBCT) and fusion imaging (FI).Materials and MethodsEight patients with T2EL were treated with DPSI using CBCT as imaging guidance. Anatomical landmarks on unenhanced CBCT were used for referencing T2EL location in the first five patients, while FI between unenhanced CBCT and pre-procedural computed tomography angiography (CTA) was used in the remaining three patients. Embolization was performed with thrombin, glue, and ethylene–vinyl alcohol copolymer. Technical and clinical success, iodinated contrast utilization, procedural time, fluoroscopy time, and mean radiation dose were registered.ResultsDPSI was technically successful in all patients: the needle was correctly positioned at the first attempt in six patients, while in two of the first five patients the needle was repositioned once. Neither minor nor major complications were registered. Average procedural time was 45 min and the average administered iodinated contrast was 13 ml. Mean radiation dose of the procedure was 60.43 Gy cm{sup 2} and mean fluoroscopy time was 18 min. Clinical success was achieved in all patients (mean follow-up of 36 months): no sign of T2EL was reported in seven patients until last CT follow-up, while it persisted in one patient with stability of sac diameter.ConclusionsDPSI using unenhanced CBCT and FI is feasible and provides the interventional radiologist with an accurate and safe alternative to endovascular treatment with limited iodinated contrast utilization.

  9. Unenhanced Cone Beam Computed Tomography and Fusion Imaging in Direct Percutaneous Sac Injection for Treatment of Type II Endoleak: Technical Note

    International Nuclear Information System (INIS)

    AimTo evaluate safety, feasibility, technical success, and clinical success of direct percutaneous sac injection (DPSI) for the treatment of type II endoleaks (T2EL) using anatomical landmarks on cone beam computed tomography (CBCT) and fusion imaging (FI).Materials and MethodsEight patients with T2EL were treated with DPSI using CBCT as imaging guidance. Anatomical landmarks on unenhanced CBCT were used for referencing T2EL location in the first five patients, while FI between unenhanced CBCT and pre-procedural computed tomography angiography (CTA) was used in the remaining three patients. Embolization was performed with thrombin, glue, and ethylene–vinyl alcohol copolymer. Technical and clinical success, iodinated contrast utilization, procedural time, fluoroscopy time, and mean radiation dose were registered.ResultsDPSI was technically successful in all patients: the needle was correctly positioned at the first attempt in six patients, while in two of the first five patients the needle was repositioned once. Neither minor nor major complications were registered. Average procedural time was 45 min and the average administered iodinated contrast was 13 ml. Mean radiation dose of the procedure was 60.43 Gy cm2 and mean fluoroscopy time was 18 min. Clinical success was achieved in all patients (mean follow-up of 36 months): no sign of T2EL was reported in seven patients until last CT follow-up, while it persisted in one patient with stability of sac diameter.ConclusionsDPSI using unenhanced CBCT and FI is feasible and provides the interventional radiologist with an accurate and safe alternative to endovascular treatment with limited iodinated contrast utilization

  10. Computed tomography of intramuscular myxoma

    International Nuclear Information System (INIS)

    Computed tomography (CT) was performed in seven patients with intramuscular myxoma. All lesions were well demarcated, of homogeneous appearance and attenuation values ranging from 10 to 60 (HU). The tumor size, as estimated at CT, correlated well with the size of the surgical specimen, which is in contrast to the findings in some high grade malignant sarcomas. (orig.)

  11. X-ray Computed Tomography.

    Science.gov (United States)

    Michael, Greg

    2001-01-01

    Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

  12. Industrial applications of computed tomography

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Carmignato, S.; Kruth, J. -P.;

    2014-01-01

    The number of industrial applications of Computed Tomography(CT) is large and rapidly increasing. After a brief market overview, the paper gives a survey of state of the art and upcoming CT technologies, covering types of CT systems, scanning capabilities, and technological advances. The paper...

  13. Computed tomography for dimensional metrology

    DEFF Research Database (Denmark)

    Kruth, J.P.; Bartscher, M.; Carmignato, S.;

    2011-01-01

    The paper gives a survey of the upcoming use of X-ray computed tomography (CT) for dimensional quality control purposes: i.e. for traceable measurement of dimensions of technical (mechanical) components and for tolerance verification of such components. It describes the basic principles of CT...

  14. Facility for positron computed tomography

    International Nuclear Information System (INIS)

    The positron computed tomography facility has got scintillator detector rings simultaneously recording more than one tomogrphic image of different cross-sections of the patient. The detectors in neighboring rings are staggered and can be rotated with respect to each other in order to increase the count rate without loss of efficiency. (DG)

  15. Computed tomography:the details.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2007-07-01

    Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.

  16. Microscopic x-ray luminescence computed tomography

    Science.gov (United States)

    Zhang, Wei; Zhu, Dianwen; Zhang, Kun; Li, Changqing

    2015-03-01

    X-ray luminescence computed tomography (XLCT) was emerged as a new hybrid imaging modality, in which the x-rays are used to excite phosphors emitting optical photons to be measured for imaging. In this paper, we reported a microscopic x-ray luminescence computed tomography (microXLCT) with a spatial resolution up to hundreds of micrometers for deep targets. We use a superfine x-ray pencil beam to scan the phosphor targets. The superfine x-ray pencil beam is generated by a small collimator mounted in front of a powerful x-ray tube (93212, Oxford Instrument). A CT detector is used to image the x-ray beam. We have generated an x-ray beam with a diameter of 192 micrometers with a collimator of 100 micrometers in diameter. The emitted optical photons on the top surface of phantom are reflected by a mirror and acquired by an electron multiplier charge-coupled device (EMCCD) camera (C9100-13, Hamamatsu Photonics). The microXLCT imaging system is built inside an x-ray shielding and light tight cabinet. The EMCCD camera is placed in a lead box. All the imaging components are controlled by a VC++ program. The optical photon propagation is modeled with the diffusion equation solved by the finite element method. We have applied different regularization methods including L2 and L1 in the microXLCT reconstruction algorithms. Numerical simulations and phantom experiments are used to validate the microXLCT imaging system.

  17. Application of Cone Beam Computed Tomography in Implant Dentistry%锥形束CT在口腔种植学中的应用

    Institute of Scientific and Technical Information of China (English)

    金柱坤

    2012-01-01

    Dental implant treatment is considered to be a conventional procedure of prosthodontics to treat edentulous jaw due to its high success rate. The introduction of new technologies in the field of dental radiology has made it possible for clinicians to more accurately evaluate jaw structure and conduct precise pre-operative planning. Cone beam CT provides a lot of potential advantages over conventional CT, including reduced effect dose,higher resolution,and fewer artifacts. Presently,cone-beam CT has been widely used in implant planning,virtual planning, surgical guide and so on. Here is to make a review on the application of cone beam computed tomography in implant dentistry.%口腔种植术由于有较高的成功率,已成为牙齿缺失修复的一种常规方法.新型的口腔放射学检查技术能使临床医师精确地评估种植区域的颌骨结构和制订准确的术前计划.与传统的医用CT相比,锥形束CT具有许多潜在的优势,例如辐射剂量的降低、高分辨率、较少的伪影等.近年来,锥形束CT在口腔种植学的植入计划、模拟计划及手术导板制作等方面的应用越来越广泛.现就锥形束CT在口腔种植学中的应用予以综述.

  18. Dosimetric effect of intrafraction motion and residual setup error for hypofractionated prostate intensity-modulated radiotherapy with online cone beam computed tomography image guidance.

    LENUS (Irish Health Repository)

    Adamson, Justus

    2012-02-01

    PURPOSE: To quantify the dosimetric effect and margins required to account for prostate intrafractional translation and residual setup error in a cone beam computed tomography (CBCT)-guided hypofractionated radiotherapy protocol. METHODS AND MATERIALS: Prostate position after online correction was measured during dose delivery using simultaneous kV fluoroscopy and posttreatment CBCT in 572 fractions to 30 patients. We reconstructed the dose distribution to the clinical tumor volume (CTV) using a convolution of the static dose with a probability density function (PDF) based on the kV fluoroscopy, and we calculated the minimum dose received by 99% of the CTV (D(99)). We compared reconstructed doses when the convolution was performed per beam, per patient, and when the PDF was created using posttreatment CBCT. We determined the minimum axis-specific margins to limit CTV D(99) reduction to 1%. RESULTS: For 3-mm margins, D(99) reduction was <\\/=5% for 29\\/30 patients. Using post-CBCT rather than localizations at treatment delivery exaggerated dosimetric effects by ~47%, while there was no such bias between the dose convolved with a beam-specific and patient-specific PDF. After eight fractions, final cumulative D(99) could be predicted with a root mean square error of <1%. For 90% of patients, the required margins were <\\/=2, 4, and 3 mm, with 70%, 40%, and 33% of patients requiring no right-left (RL), anteroposterior (AP), and superoinferior margins, respectively. CONCLUSIONS: For protocols with CBCT guidance, RL, AP, and SI margins of 2, 4, and 3 mm are sufficient to account for translational errors; however, the large variation in patient-specific margins suggests that adaptive management may be beneficial.

  19. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... gantry. The computer workstation that processes the imaging information is located ... in detector technology allow nearly all CT scanners to obtain multiple ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... gantry. The computer workstation that processes the imaging information is located ... in detector technology allow nearly all CT scanners to obtain multiple ...

  1. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is located in a separate control room, where ...

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Rotating around you, the x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry. The computer workstation that processes the imaging information is located in a separate control room, where ...

  3. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... a gantry, which rotates around the patient. The computer that processes the imaging information and monitor are located in ... ray beam follows a spiral path. A special computer program processes this series of pictures, or slices of the ...

  4. Beam hardening artefacts in computed tomography with photon counting, charge integrating and energy weighting detectors: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Shikhaliev, Polad M [Department of Radiological Sciences, University of California, Irvine, CA 92697 (United States)

    2005-12-21

    Photon counting x-ray imaging provides efficient rejection of the electronics noise, no pulse height (Swank) noise, less noise due to optimal photon energy weighting and the possibility of energy resolved image acquisition. These advantages apply also to CT when projection data are acquired using a photon counting detector. However, photon counting detectors assign a weighting factor of 1 to all detected photons whereas the weighting factor of a charge integrating detector is proportional to the energy of the detected photon. Therefore, data collected by photon counting and charge integrating detectors represent the 'hardening' of the photon beam passed through the object differently. This affects the beam hardening artefacts in the reconstructed CT images. This work represents the first comparative evaluation of the effect of photon counting, charge integrating and energy weighting photon detectors on beam hardening artefacts in CT. Beam hardening artefacts in CT images were evaluated for 20 cm and 14 cm diameter water cylinders with bone and low contrast inserts, at 120 kVp and 90 kVp x-ray tube voltages, respectively. It was shown that charge integrating results in 1.8% less beam hardening artefacts from bone inserts (i.e., CT numbers in the 'shadow' of the bone are less by 1.8% as compared to CT numbers over the periphery of the image), as compared to photon counting. However, optimal photon energy weighting, which provides highest SNR, results in 7.7% higher beam hardening artefacts from bone inserts as compared to photon counting. The magnitude of the 'cupping' artefacts was lower by 1% for charge integrating and higher by 6.1% for energy weighting acquisitions as compared to photon counting. Only the photon counting systems provide an accurate representation of the beam hardening effect due to its flat energy weighting. Because of their energy dependent weighting factors, the charge integrating and energy weighting systems do

  5. Pediatric cranial computed tomography

    International Nuclear Information System (INIS)

    The introduction of CT in the investigation of intercranial pathology has revolutionized the approach to clinical neurological and neurosurgical practice. This book applies the advances of cranial CT to the pediatric patient. The test is divided into two sections. The first portion describes the practical methodology, anatomy and normal and abnormal CT scan appearance, including high or low density lesions, cystic lesions and ventricular or subarachnoid space dilation. The characteristic scans for various neurological diseases are presented and discussed. The author has given special attention to the CT diagnosis of congenital malformations and cerebral neoplasms. Partial Contents: Normal Computed Tomographic Anatomy/ High Density Lesions/Low Density Lesions/Cystic Lesions; Supratentorial/Cystic Lesions; Infratentorial/Increased Head Circumference/Increased Ventricular Size/Small Ventricular Size/Cranial Lesions/Spinal Lesions/CT Cisternography/Part II CT in Neonates/Congenital Craniocerebral Malformations/Hydrocephalus/Craniosynostosis/Head Trauma/Cerebrovascular Lesions/Intracranial Lesions/Seizure Disorders/Intracranial and Other Chronic Neurological Disorders

  6. Development of Methods for Scatter Artifact Correction in Industrial X-ray Cone-beam Computed Tomography

    OpenAIRE

    Schörner, Karsten

    2012-01-01

    Scattered radiation presents a major cause of image degradation for industrial X-ray cone-beam CT scanners. It introduces several kinds of artifacts in reconstructed CT volumes, such as streaks, a general loss of contrast, and inhomogeneities known as cupping artifact. In this work, we study different scattering sources which contribute to the total detected signal and we develop methods for the correction of these secondary contributions. A novel method, based on the temporal modulation of t...

  7. Contemporary management of horizontal root fractures to the permanent dentition: diagnosis--radiologic assessment to include cone-beam computed tomography.

    Science.gov (United States)

    May, Jeremy J; Cohenca, Nestor; Peters, Ove A

    2013-03-01

    Historically, obtaining several periapical radiographs has been recommended to diagnose horizontal root fractures. Assessing the 3-dimensional orientation of a fracture is correlated to treatment and outcome. However, conventional radiography yields only limited information for accurate diagnosis. Cone-beam computed tomography (CBCT) is a relatively new and useful technology, which provides an auxiliary imaging modality to supplement conventional radiography for evaluating horizontal root fractures. Despite the increasing application of this technology as well as a growing body of evidence supporting its value in diagnosing horizontal root fractures, there are no specific guidelines for its use. This article aimed to provide such preliminary guidelines for cases of suspected horizontal root fracture as a result of trauma. From a database search it was concluded that CBCT is most useful in cases in which conventional radiography yields inconclusive results or shows a fracture in the middle third of a root. In such cases CBCT may rule out false negatives, ie, a suspected root fracture not visualized with conventional radiography. For a root fracture in the middle third, CBCT may rule out or confirm an oblique course of fracture involving the cervical third in the labiolingual dimension. Although there are considerable advantages when CBCT is included in the assessment of horizontal root fracture and its possible sequelae, more experimental and clinical studies are warranted to determine the exact impact on outcomes. PMID:23439041

  8. Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

    Science.gov (United States)

    Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

    2014-10-01

    The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. PMID:25015906

  9. The effect of metal artifacts on the identification of vertical root fractures using different fields of view in cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Moudi, Ehsan; Haghanifar, Sina; Madani, Zahrasadat; Bijani, Ali; Nabavi, Zeynab Sadat [Babol University of Medical Science, Babol (Iran, Islamic Republic of)

    2015-09-15

    The aim of this study was to investigate the effects of metal artifacts on the accurate diagnosis of root fractures using cone-beam computed tomography (CBCT) images with large and small/limited fields of view (FOVs). Forty extracted molar and premolar teeth were collected. Access canals were made in all teeth using a rotary system. In half of the teeth, fractures were created by the application of mild pressure with a hammer. The teeth were then randomly put into a wax rim on an acryl base designed in the shape of a mandible. CBCT scans were obtained using a Newtom 5G system with FOVs of 18 cm×16 cm and 6 cm×6 cm. A metal pin was then placed into each tooth, and CBCT imaging was again performed using the same fields of view. All scans were evaluated by two oral and maxillofacial radiologists. The specificity, sensitivity, positive predictive value, negative predictive value, and likelihood ratios (positive and negative) were calculated. The maximum levels of sensitivity and specificity (100% and 100%, respectively) were observed in small volume CBCT scans of teeth without pins. The highest negative predictive value was found in the small-volume group without pins, whereas the positive predictive value was 100% in all groups except the large-volume group with pins.

  10. Initial Report on the Use of In-Office Cone Beam Computed Tomography for Early Diagnosis of Osteomyelitis in Diabetic Patients.

    Science.gov (United States)

    Shih, Chia-Ding; Bazarov, Irina; Harrington, Tara; Vartivarian, Mher; Reyzelman, Alexander M

    2016-03-01

    Osteomyelitis is one of the most feared sequelae of diabetic foot ulceration, which often leads to lower-extremity amputation and disability. Early diagnosis of osteomyelitis increases the likelihood of successful treatment and may limit the amount of bone resected, preserving ambulatory function. Although a variety of techniques exist for imaging the diabetic foot, standard radiography is still the only in-office imaging modality used today. However, radiographs lack sensitivity and specificity, making it difficult to diagnose bone infection at its early stages. In this report, we describe our initial experience with a cone beam computed tomography (CBCT)-based device, which may serve as an accurate and readily available tool for early diagnosis of osteomyelitis in a patient with diabetes. Two patients with infected diabetic foot ulcers were evaluated for osteomyelitis using radiography and CBCT. Positive imaging findings were confirmed by bone biopsy. In both patients, CBCT captured early osteolytic changes that were not apparent on radiographs, leading to early surgical intervention and successful treatment. The CBCT was helpful in facilitating detection and early clinical intervention for osteomyelitis in two diabetic patients with foot ulcers. These results are encouraging and warrant future evaluation. PMID:27031549

  11. A moving blocker-based strategy for simultaneous megavoltage and kilovoltage scatter correction in cone-beam computed tomography image acquired during volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Purpose: To evaluate a moving blocker-based approach in estimating and correcting megavoltage (MV) and kilovoltage (kV) scatter contamination in kV cone-beam computed tomography (CBCT) acquired during volumetric modulated arc therapy (VMAT). Methods and materials: During the concurrent CBCT/VMAT acquisition, a physical attenuator (i.e., “blocker”) consisting of equally spaced lead strips was mounted and moved constantly between the CBCT source and patient. Both kV and MV scatter signals were estimated from the blocked region of the imaging panel, and interpolated into the unblocked region. A scatter corrected CBCT was then reconstructed from the unblocked projections after scatter subtraction using an iterative image reconstruction algorithm based on constraint optimization. Experimental studies were performed on a Catphan® phantom and an anthropomorphic pelvis phantom to demonstrate the feasibility of using a moving blocker for kV–MV scatter correction. Results: Scatter induced cupping artifacts were substantially reduced in the moving blocker corrected CBCT images. Quantitatively, the root mean square error of Hounsfield units (HU) in seven density inserts of the Catphan phantom was reduced from 395 to 40. Conclusions: The proposed moving blocker strategy greatly improves the image quality of CBCT acquired with concurrent VMAT by reducing the kV–MV scatter induced HU inaccuracy and cupping artifacts

  12. Electronic beam computer tomography and transthoracical echocardiography in postoperative after-treatment after orthoheart transplantation, clinical study before, during and after rejection therapy

    International Nuclear Information System (INIS)

    Nine pacemaker-stimulated patients with mild acute rejection were examined before, during, one week and six weeks (where the biopsy showed no rejection) after rejection therapy (methylprednisolon 1000 mg for three) with transthoracical echocardiography and electronic beam computer tomography (EBT). Ten patients with mild acute rejection without pacemaker stimulation were compared with the stimulated patients. The ejection fraction (EF) increased during therapy and decreased one week after therapy significantly in the stimulated, slightly in the control group. There were no echocardiographic parameters (EF, left and right ventricular diameters, wall thickness, flow and pressure above aortic and pulmonary valves) which showed significant differences before and six weeks after therapy. The EBT showed a significant decrease of left ventricular wall thickness and left ventricular mass. Transthoracical echocardiography seems to be no predicative method in the diagnosis mild acute heart allograft rejection. EBT could be a practicable noninvasive method to state acute heart allograft rejections. The effect of the methylprednisolone therapy could be associated with rejection. (author)

  13. A morphological comparison of the piriform sinuses in head-on and head-rotated views of seated subjects using cone-beam computed tomography

    International Nuclear Information System (INIS)

    Food flow in the oropharynx changes when the head is rotated. The purpose of this study was to evaluate morphological differences in the upper and lower piriform sinuses in head-on (HO) versus head-rotated (HR) positions. Ten healthy adult volunteers with no previous history of dysphagia were subjected to cone-beam computed tomography (CBCT) in the HO and HR positions. Binary CBCT images were created at 50% gray scale to examine morphological changes in the lower piriform sinuses. Upon rotation to the right, the cross-sectional area of the left lower piriform sinus increased significantly (P=0.037). The depth of the right lower piriform sinus also increased significantly (P=0.011) upon rotation. The volume of the lower piriform sinuses increased significantly on both sides (right, P=0.009; left, P=0.013). The upper piriform sinuses acquired a teardrop shape, with the rotated side narrowed and opposite side enlarged. These results suggest that changes in food flow during head rotation result mainly from changes in the size and shape of the upper piriform sinuses. (author)

  14. Cone-beam computed tomography study of the root and canal morphology of mandibular permanent anterior teeth in a Chongqing population

    Science.gov (United States)

    Zhengyan, Yang; Keke, Lu; Fei, Wang; Yueheng, Li; Zhi, Zhou

    2016-01-01

    Objective To investigate the root and canal morphology of permanent mandibular anterior teeth in a Chongqing population using cone-beam computed tomography (CBCT). Methods CBCT images of 1,725 patients in a Chongqing population were selected, and a total of 9,646 mandibular anterior teeth were analyzed. The number of root canals and the canal configurations were investigated. Results In total, 0.3% (11/3,257) of lateral incisors and 0.8% (26/3,014) of canines had double roots, and 3.8% (127/3,375) of central incisors, 10.6% (345/3,257) of lateral incisors, and 4.2% (127/3,014) of canines had multi-root canals. The difference in the incidence of multi-canals in lateral incisors between female and male was statistically significant. The frequency of multi-canals in the different age groups was 5.0% for central incisors for ages 21–30 years, 14.7% for lateral incisors for ages 41–50 years, and 8.1% for canines for ages 41–50 years. Conclusion With the limitations of the current study, we found that a high percentage of mandibular anterior teeth had multiple canals in the studied Chinese Chongqing population. The current data may provide clinicians practicing in Chongqing with a more thorough understanding of root canal morphology. PMID:26730198

  15. Comparative evaluation of soft and hard tissue dimensions in the anterior maxilla using radiovisiography and cone beam computed tomography: A pilot study

    Directory of Open Access Journals (Sweden)

    Savita Mallikarjun

    2016-01-01

    Full Text Available Aims: To assess and compare the thickness of gingiva in the anterior maxilla using radiovisiography (RVG and cone beam computed tomography (CBCT and its correlation with the thickness of underlying alveolar bone. Settings and Design: This cross-sectional study included 10 male subjects in the age group of 20–45 years. Materials and Methods: After analyzing the width of keratinized gingiva of the maxillary right central incisor, the radiographic assessment was done using a modified technique for RVG and CBCT, to measure the thickness of both the labial gingiva and labial plate of alveolar bone at 4 predetermined locations along the length of the root in each case. Statistical Analysis Used: Statistical analysis was performed using Student's t-test and Pearson's correlation test, with the help of statistical software (SPSS V13. Results: No statistically significant differences were obtained in the measurement made using RVG and CBCT. The results of the present study also failed to reveal any significant correlation between the width of gingiva and the alveolar bone in the maxillary anterior region. Conclusions: Within the limitations of this study, it can be concluded that both CBCT and RVG can be used as valuable tools in the assessment of the soft and hard tissue dimensions.

  16. Diagnostic investigation of the abdominal vasculature by means of electron-beam computed tomography; Diagnostik des abdominellen Gefaesssystems mit der Elektronenstrahlcomputertomographie (EBT)

    Energy Technology Data Exchange (ETDEWEB)

    Vogl, T.J.; Diebold, T. [Frankfurt Univ. (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Hammerstingl, R.; Balzer, J.O.; Hidajat, N.; Beier, J.; Felix, R. [Strahlen- und Poliklinik, Humboldt Univ. Berlin Charite, Campus Virchow (Germany); Zipfel, B. [Deutsches Herzzentrum Berlin (Germany). Abt. fuer Herz-, Thorax und Gefaesschirurgie; Scheinert, D.; Vogt, A. [Abt. fuer Innere Medizin, Medizinische Klinik und Poliklinik, Charite, Campus Virchow, Berlin Univ. (Germany)

    1998-12-01

    Purpose: To evaluate the potential of electron-beam computed tomography (EBT) in the pre- and postinterventional assessment of vascular abdominal pathologies. Results: In 30 to 40 TIPS patients, identical results were found with EBT, Doppler sonography and/or DSA. Reduced perfusions of the TIPS, which were subsequently confirmed by DSA, could not be shown with EBT in 3 patients. Nine of 12 patients with peripheral arterial occlusive disease and angiographically proven stenosis (>75%) showed a reduced and delayed peak density of the time-density curves. The quantification of arterial stenosis, however, did not follow the angiographic values. In all patients with the implanted bifurcation stents, EBT could correctly exclude a leakage of the stent. (orig./AJ) [Deutsch] Fragestellung: Die vorliegende Studie untersucht die Wertigkeit der Elektronenstrahlcomputertomographie (EBT) bei der prae- und postinterventionellen Abklaerung von Pathologien des arteriellen und portalvenoesen Gefaesssystems. Ergebnisse: Bei 30/40 TIPS-Patienten stimmte die EBT mit der Dopplersonographie bzw. der DSA ueberein, bei 3 Patienten konnte eine dopplersonographisch nachgewiesene und interventionell bestaetigte Minderperfusion des TIPS im EBT nicht diagnostiziert werden. Bei 9/12 Patienten mit angiographisch nachgewiesenen Gefaessstenosen (>75%) konnte eine Abflachung und ein verzoegerter Anstieg der Zeit-Dichte-Kurven nachgewiesen werden. Die Quantifizierung der Stenose mit den Zeit-Dichte-Kurven zeigte jedoch nur eine eingeschraenkte Korrelation mit der i.a.-DSA. Bei den Patienten mit endovaskulaer implantierter Aortenprothese konnte in allen Faellen eine komplette Ausschaltung des Aortenaneurysmas nachgewiesen werden. (orig./AJ)

  17. Comparison of focused ion beam versus nano-scale X-ray computed tomography for resolving 3-D microstructures of porous fuel cell materials

    Science.gov (United States)

    Wargo, E. A.; Kotaka, T.; Tabuchi, Y.; Kumbur, E. C.

    2013-11-01

    Focused ion beam-scanning electron microscopy (FIB-SEM) and nano-scale X-ray computed tomography (nano-CT) have emerged as two popular nanotomography techniques for quantifying the 3-D microstructure of porous materials. The objective of this study is to assess the unique features and limitations of FIB-SEM and nano-CT in capturing the 3-D microstructure and structure-related transport properties of porous fuel cell materials. As a test case, a sample of a micro-porous layer used in polymer electrolyte fuel cells is analyzed to obtain 3-D microstructure datasets using these two nanotomography techniques. For quantitative comparison purposes, several key transport properties are determined for these two datasets, including the porosity, pore connectivity, tortuosity, structural diffusivity coefficient, and chord length (i.e., void size) distributions. The results obtained for both datasets are evaluated against each other and experimental data when available. Additionally, these two techniques are compared qualitatively in terms of the acquired images, image segmentation, and general systems operation. The particular advantages and disadvantages of both techniques are highlighted, along with suggestions for best practice.

  18. Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images

    Science.gov (United States)

    Kim, Jooseong

    2016-01-01

    Objective The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. Methods CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Results Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis. PMID:26877978

  19. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    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); Lambrichts, Ivo, E-mail: Ivo.Lambrichts@uhasselt.b [Department of Basic Medical Sciences, Histology and Electron Microscopy, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Sun Yi, E-mail: Sunyihello@hotmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Denis, Kathleen, E-mail: kathleen.denis@groept.b [Department of Industrial Sciences and Techology-Engineering (IWT), XIOS Hogeschool Limburg, Hasselt (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); 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)

    2010-08-15

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  20. Comparison of panoramic radiography and cone beam computed tomography for assessing the relationship between the maxillary sinus floor and maxillary molars

    International Nuclear Information System (INIS)

    This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor.

  1. Effect of titanium and stainless steel posts in detection of vertical root fractures using NEWTOM VG cone beam computed tomography system

    International Nuclear Information System (INIS)

    Vertical root fracture (VRF) is a common complication in endodontically treated teeth. Considering the poor prognosis of VRF, a reliable and valid detection method is necessary. Cone beam computed tomography (CBCT) has been reported to be a reliable tool for the detection of VRF; however, the presence of metallic intracanal posts can decrease the diagnostic values of CBCT systems. This study evaluated and compared the effects of intracanal stainless steel or titanium posts on the sensitivity, specificity, and accuracy of VRF detection using a NewTom VG CBCT system. Eighty extracted single-rooted teeth were selected and sectioned at the cemento-enamel junction. The roots were divided into two groups of 40. Root fracture was induced in the test group by using an Instron machine, while the control group was kept intact. Roots were randomly embedded in acrylic blocks and radiographed with the NewTom VG, both with titanium and stainless steel posts and also without posts. Sensitivity, specificity, and accuracy values were calculated as compared to the gold standard. The sensitivity, specificity, and accuracy of VRF diagnosis were significantly lower in teeth with stainless steel and titanium posts than in those without posts. Interobserver agreement was the highest in teeth without posts, followed by stainless steel posts, and then titanium posts. Intracanal posts significantly decreased the VRF diagnostic values of CBCT. The stainless steel posts decreased the diagnostic values more than the titanium posts.

  2. Evaluation of diagnostic accuracy of conventional and digital periapical radiography, panoramic radiography, and cone-beam computed tomography in the assessment of alveolar bone loss

    Science.gov (United States)

    Takeshita, Wilton Mitsunari; Vessoni Iwaki, Lilian Cristina; Da Silva, Mariliani Chicarelli; Tonin, Renata Hernandes

    2014-01-01

    Background: To evaluate the diagnostic accuracy of different radiographic methods in the assessment of proximal alveolar bone loss (ABL). Materials and Methods: ABL, the distance between cement-enamel junction and alveolar bone crest, was measured in 70 mandibular human teeth – directly on the mandibles (control), using conventional periapical radiography with film holders (Rinn XCP and Han-Shin), digital periapical radiography with complementary metal-oxide semiconductor sensor, conventional panoramic, and cone-beam computed tomography (CBCT). Three programs were used to measure ABL on the images: Image tool 3.0 (University of Texas Health Sciences Center, San Antonio, Texas, USA), Kodak Imaging 6.1 (Kodak Dental Imaging 6.1, Carestream Health®, Rochester, NY, USA), and i-CAT vision 1.6.20. Statistical analysis used ANOVA and Tukey's test at 5% significance level. Results: The tomographic images showed the highest means, whereas the lowest were found for periapical with Han-Shin. Controls differed from periapical with Han-Shin (P digital periapical (P = 0.0027). Conventional periapicals with film holders differed from each other (P = 0.0007). Digital periapical differed from conventional periapical with Han-Shin (P = 0.0004). Conclusions: Conventional periapical with Han-Shin film holder was the only method that differed from the controls. CBCT had the closest means to the controls. PMID:25191066

  3. Prevalence of bony septa, antral pathology, and dimensions of the maxillary sinus from a sinus augmentation perspective: A retrospective cone-beam computed tomography study

    Science.gov (United States)

    Jalali, Elnaz; Al-Salman, Wesam; Jambhekar, Shantanu; Katechia, Bina; Almas, Khalid

    2016-01-01

    Purpose Sinus elevation procedures have become a routine and reliable way to gain bone volume in the edentulous maxilla for dental implant placement. Presence of bony septations and pathology in the maxillary sinus often cause complications leading to graft or implant failure or both. The aim of this study was to retrospectively evaluate the prevalence of pathology, direction of the septa, and sinus width measured at 2 mm, 5 mm, and 10 mm from the sinus floor in maxillary sinuses using cone-beam computed tomography (CBCT). Materials and Methods Seventy-two sinuses from 36 random preoperative CBCT scans referred for implant therapy were retrospectively evaluated for the number, prevalence, and direction of bony septations and presence of pathology. Width of the sinus was also measured at 2 mm, 5 mm, and 10 mm from the sinus floor to account for the amount of bone available for implant placement. Results Maxillary sinus septa were found in 59.7%. Presence of a single septum was noted in 20 sinuses (27.7%), followed by two septa in 17 sinuses. The most common direction of the septum was the transverse direction. Retention pseudocyst and mucosal thickening were the most commonly seen abnormality/pathology. Conclusion Based on the high prevalence of septa and sinus pathology in this sample, a preoperative CBCT scan might be helpful in minimizing complications during sinus augmentation procedures for dental implant therapy. PMID:27358818

  4. Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Andres; Jacobs, Reinhilde; Lambrechts, Paul [Katholieke Universiteit Leuven, Leuven (Belgium); Brizuela, Claudia; Cabrera, Carolina; Concha, Guillermo; Pedemonte, Maria Eugenia [Universidad de los Andes, Santiago (Chile)

    2015-06-15

    This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning.

  5. Pneumatized articular eminence in a cohort of orthodontic patients with different sagittal skeletal anomalies. A retrospective cone beam computed tomography study

    International Nuclear Information System (INIS)

    The aim of this study was to determine the prevalence and characteristics of pneumatized articular eminence (PAE) in dental patients using cone beam computed tomography (CBCT) with respect to age, sex, and type of skeletal anomaly. The results were then compared to prevalence studies regarding PAE in the literature. A retrospective study of 603 orthodontic patients aged between 6 and 24 years was performed using sagittal and coronal CBCT images at the Department of Oral and Maxillofacial Radiology (Erzurum, Turkey). The age, gender, skeletal anomaly, and lateral were recorded for all patients, and the types were noted for cases of PAE. The chi-squared test was used for statistical analyses. Sixty-four PAEs were found in 39 orthodontic patients, representing a prevalence of 6.47%. No significant differences in sex (p=0.153), age (before and after puberty, p=0.389), and type of skeletal anomaly were observed (p=0.271). A higher frequency of PAE was detected among dental patients aged 6-24 years when compared to previous studies, most likely because of the use of CBCT images. No significant relation was observed between PAE and the type of skeletal anomalies. One, however, must be aware of these structures to avoid complications in cases for which surgical treatment is planned due to the occlusion and recognize its role in the onset or perpetuation of temporomandibular joint dysfunction. (author)

  6. Assessment of anterior-posterior jaw relationships in Korean adults using the nasion true vertical plane in cone-beam computed tomography images

    Science.gov (United States)

    Park, Youngju; Cho, Youngserk; Mah, James

    2016-01-01

    Objective The aims of this study were to investigate a simple method for assessing anterior-posterior jaw relationships via cone-beam computed tomography (CBCT) images taken in the natural head position (NHP) relative to the nasion true vertical plane (NTVP), and measure normative data in Korean adults with normal profiles. Methods Subjects were selected from patients presenting for third molar extraction and evaluated as having normal profiles by three examiners. The CBCT images of 80 subjects (39 males, 41 females) were taken in the NHP according to Solow and Tallgren's method. Linear measurements of the A-point, B-point, and Pog were calculated relative to the NTVP. Student's t-test was used to assess sexual differences in these measurements. Results The mean linear measurements of the A-point, B-point, and Pog relative to the NTVP were 0.18 mm (standard deviation [SD], 4.77 mm), −4.00 mm (SD, 6.62 mm), and −2.49 mm (SD, 7.14 mm) respectively in Korean males, and 1.48 mm (SD, 4.21 mm), −4.07 mm (SD, 6.70 mm) and −2.91 mm (SD, 7.25 mm) in Korean females respectively. There were no statistically significant differences between Korean males and females (p < 0.05). Conclusions Three-dimensional CBCT analysis using the NTVP is a simple and reliable method for assessing anterior-posterior skeletal relationships. PMID:27226962

  7. A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

    International Nuclear Information System (INIS)

    Aim: The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm. Results: The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively. Conclusion: The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

  8. Characterization of mandibular molar root and canal morphology using cone beam computed tomography and its variability in Belgian and Chilean population samples

    International Nuclear Information System (INIS)

    This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning

  9. Effect of titanium and stainless steel posts in detection of vertical root fractures using NEWTOM VG cone beam computed tomography system

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadpour, Mahdis [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Qazvin University of Medical Sciences, Qazvin (Iran, Islamic Republic of); Bakhshalian, Neema [Dept. of Advanced Periodontology, Ostrow School of Dentistry, University of Southern California, Los Angeles (United States); Shahab, Shahriar [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Shahed University, Tehran (Iran, Islamic Republic of); Sadeghi, Shaya; Ataee, Mona [Radmehr Oral and Maxillofacial Radiology Clinic, Ghazvin (Iran, Islamic Republic of); Sarikhani, Soodeh [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, University of Golestan, Gorgan (Iran, Islamic Republic of)

    2014-06-15

    Vertical root fracture (VRF) is a common complication in endodontically treated teeth. Considering the poor prognosis of VRF, a reliable and valid detection method is necessary. Cone beam computed tomography (CBCT) has been reported to be a reliable tool for the detection of VRF; however, the presence of metallic intracanal posts can decrease the diagnostic values of CBCT systems. This study evaluated and compared the effects of intracanal stainless steel or titanium posts on the sensitivity, specificity, and accuracy of VRF detection using a NewTom VG CBCT system. Eighty extracted single-rooted teeth were selected and sectioned at the cemento-enamel junction. The roots were divided into two groups of 40. Root fracture was induced in the test group by using an Instron machine, while the control group was kept intact. Roots were randomly embedded in acrylic blocks and radiographed with the NewTom VG, both with titanium and stainless steel posts and also without posts. Sensitivity, specificity, and accuracy values were calculated as compared to the gold standard. The sensitivity, specificity, and accuracy of VRF diagnosis were significantly lower in teeth with stainless steel and titanium posts than in those without posts. Interobserver agreement was the highest in teeth without posts, followed by stainless steel posts, and then titanium posts. Intracanal posts significantly decreased the VRF diagnostic values of CBCT. The stainless steel posts decreased the diagnostic values more than the titanium posts.

  10. Analysis of vector models in quantification of artifacts produced by standard prosthetic inlays in Cone-Beam Computed Tomography (CBCT)--a preliminary study.

    Science.gov (United States)

    Różyło-Kalinowska, Ingrid; Miechowicz, Sławomir; Sarna-Boś, Katarzyna; Borowicz, Janusz; Kalinowski, Paweł

    2014-01-01

    Cone-beam computed tomography (CBCT) is a relatively new, but highly efficient imaging method applied first in dentistry in 1998. However, the quality of the obtained slices depends among other things on artifacts generated by dental restorations as well as orthodontic and prosthetic appliances. The aim of the study was to quantify the artifacts produced by standard prosthetic inlays in CBCT images. The material consisted of 17 standard prosthetic inlays mounted in dental roots embedded in resin. The samples were examined by means of a large field of view CBCT unit, Galileos (Sirona, Germany), at 85 kV and 14 mAs. The analysis was performed using Able 3DDoctor software for data in the CT raster space as well as by means of Materialise Magics software for generated vector models (STL). The masks generated in the raster space included the area of the inlays together with image artifacts. The region of interest (ROI) of the raster space is a set of voxels from a selected range of Hounsfield units (109-3071). Ceramic inlay with zirconium dioxide (Cera Post) as well as epoxy resin inlay including silica fibers enriched with zirconium (Easy Post) produced the most intense artifacts. The smallest image distortions were created by titanium inlays, both passive (Harald Nordin) and active (Flexi Flange). Inlays containing zirconium generated the strongest artifacts, thus leading to the greatest distortions in the CBCT images. Carbon fiber inlay did not considerably affect the image quality. PMID:25404623

  11. Radiation dose and image quality of X-ray volume imaging systems: cone-beam computed tomography, digital subtraction angiography and digital fluoroscopy

    International Nuclear Information System (INIS)

    Radiation dose and image quality estimation of three X-ray volume imaging (XVI) systems. A total of 126 patients were examined using three XVI systems (groups 1-3) and their data were retrospectively analysed from 2007 to 2012. Each group consisted of 42 patients and each patient was examined using cone-beam computed tomography (CBCT), digital subtraction angiography (DSA) and digital fluoroscopy (DF). Dose parameters such as dose-area product (DAP), skin entry dose (SED) and image quality parameters such as Hounsfield unit (HU), noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were estimated and compared using appropriate statistical tests. Mean DAP and SED were lower in recent XVI than its previous counterparts in CBCT, DSA and DF. HU of all measured locations was non-significant between the groups except the hepatic artery. Noise showed significant difference among groups (P < 0.05). Regarding CNR and SNR, the recent XVI showed a higher and significant difference compared to its previous versions. Qualitatively, CBCT showed significance between versions unlike the DSA and DF which showed non-significance. A reduction of radiation dose was obtained for the recent-generation XVI system in CBCT, DSA and DF. Image noise was significantly lower; SNR and CNR were higher than in previous versions. The technological advancements and the reduction in the number of frames led to a significant dose reduction and improved image quality with the recent-generation XVI system. (orig.)

  12. Quantitative assessment of scattering contributions in high energy cone-beam computed tomography; Quantitative Untersuchung der Streubeitraege in Hochenergie-Roentgencomputertomografie

    Energy Technology Data Exchange (ETDEWEB)

    Stritt, Carina; Schuetz, Philipp; Plamondon, Mathieu; Hofmann, Juergen; Sennhauser, Urs [Empa, Duebendorf (Switzerland). Reliability Science and Technology Laboratory; Flisch, Alexander [Empa, Duebendorf (Switzerland). Reliability Science and Technology Laboratory; Empa, Duebendorf (Switzerland). Center for X-Ray Analytics

    2016-02-01

    X-ray computed tomography (CT) is an established method in the fields of failure analysis and quality control. The energy of the X-ray beam determines the penetration length of the radiation and hereby limits the size and the density of the object that is investigated. For the case of large, dense and heavy objects, X-ray energies exceeding one mega electronvolt (MeV) are needed to achieve measureable transmission values. An important factor for the quality of X-ray CT is the contribution of scattered radiation in the radiographies. X-ray photons can be scattered from the object as well as the instrumentation and the environment which leads to a distorted transmission image. Besides scattered radiation, the physical effect of pair production has to be taken into account for radiation in the range of MeV. This work investigates the impact of each of the scattering processes on the radiography. Detailed Monte Carlo simulations help to distinguish the physical interactions as well as scattered radiation from system components. In contrast to previous studies, not only a set of simple geometric objects made of different materials is examined, but also models of the components of a CT scanner are used to estimate the contribution of scattering of various system components.

  13. Positron emission tomography/computed tomography.

    Science.gov (United States)

    Townsend, David W

    2008-05-01

    Accurate anatomical localization of functional abnormalities obtained with the use of positron emission tomography (PET) is known to be problematic. Although tracers such as (18)F-fluorodeoxyglucose ((18)F-FDG) visualize certain normal anatomical structures, the spatial resolution is generally inadequate for accurate anatomic localization of pathology. Combining PET with a high-resolution anatomical imaging modality such as computed tomography (CT) can resolve the localization issue as long as the images from the two modalities are accurately coregistered. However, software-based registration techniques have difficulty accounting for differences in patient positioning and involuntary movement of internal organs, often necessitating labor-intensive nonlinear mapping that may not converge to a satisfactory result. Acquiring both CT and PET images in the same scanner obviates the need for software registration and routinely provides accurately aligned images of anatomy and function in a single scan. A CT scanner positioned in line with a PET scanner and with a common patient couch and operating console has provided a practical solution to anatomical and functional image registration. Axial translation of the couch between the 2 modalities enables both CT and PET data to be acquired during a single imaging session. In addition, the CT images can be used to generate essentially noiseless attenuation correction factors for the PET emission data. By minimizing patient movement between the CT and PET scans and accounting for the axial separation of the two modalities, accurately registered anatomical and functional images can be obtained. Since the introduction of the first PET/CT prototype more than 6 years ago, numerous patients with cancer have been scanned on commercial PET/CT devices worldwide. The commercial designs feature multidetector spiral CT and high-performance PET components. Experience has demonstrated an increased level of accuracy and confidence in the

  14. Computed tomography of gynecologic diseases