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Sample records for cone beam computer

  1. Panoramic cone beam computed tomography

    SciTech Connect

    Chang Jenghwa; Zhou Lili; Wang Song; Clifford Chao, K. S.

    2012-05-15

    Purpose: Cone-beam computed tomography (CBCT) is the main imaging tool for image-guided radiotherapy but its functionality is limited by a small imaging volume and restricted image position (imaged at the central instead of the treatment position for peripheral lesions to avoid collisions). In this paper, the authors present the concept of ''panoramic CBCT,'' which can image patients at the treatment position with an imaging volume as large as practically needed. Methods: In this novel panoramic CBCT technique, the target is scanned sequentially from multiple view angles. For each view angle, a half scan (180 deg. + {theta}{sub cone} where {theta}{sub cone} is the cone angle) is performed with the imaging panel positioned in any location along the beam path. The panoramic projection images of all views for the same gantry angle are then stitched together with the direct image stitching method (i.e., according to the reported imaging position) and full-fan, half-scan CBCT reconstruction is performed using the stitched projection images. To validate this imaging technique, the authors simulated cone-beam projection images of the Mathematical Cardiac Torso (MCAT) thorax phantom for three panoramic views. Gaps, repeated/missing columns, and different exposure levels were introduced between adjacent views to simulate imperfect image stitching due to uncertainties in imaging position or output fluctuation. A modified simultaneous algebraic reconstruction technique (modified SART) was developed to reconstruct CBCT images directly from the stitched projection images. As a gold standard, full-fan, full-scan (360 deg. gantry rotation) CBCT reconstructions were also performed using projection images of one imaging panel large enough to encompass the target. Contrast-to-noise ratio (CNR) and geometric distortion were evaluated to quantify the quality of reconstructed images. Monte Carlo simulations were performed to evaluate the effect of scattering on the image quality and

  2. Cone beam computed tomography use in orthodontics.

    PubMed

    Nervina, J M

    2012-03-01

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

  3. Cone Beam Computed Tomography - Know its Secrets

    PubMed Central

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

    2015-01-01

    Cone-beam computed tomography (CBCT) is an advanced imaging modality that has high clinical applications in the field of dentistry. CBCT proved to be a successful investigative modality that has been used for dental and maxillofacial imaging. Radiation exposure dose from CBCT is 10 times less than from conventional CT scans during maxillofacial exposure. Furthermore, CBCT is highly accurate and can provide a three-dimensional volumetric data in axial, sagittal and coronal planes. This article describes the basic technique, difference in CBCT from CT and main clinical applications of CBCT. PMID:25859112

  4. Cone beam computed tomography in endodontics.

    PubMed

    Durack, Conor; Patel, Shanon

    2012-01-01

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

  5. Skeletal dosimetry in cone beam computed tomography

    SciTech Connect

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

    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.

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

    PubMed

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

    2015-01-01

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

  7. Cone beam computed tomography scanning and diagnosis for dental implants.

    PubMed

    Greenberg, Alex M

    2015-05-01

    Cone beam computed tomography (CBCT) has become an important new technology for oral and maxillofacial surgery practitioners. CBCT provides improved office-based diagnostic capability and applications for surgical procedures, such as CT guidance through the use of computer-generated drill guides. A thorough knowledge of the basic science of CBCT as well as the ability to interpret the images correctly and thoroughly is essential to current practice. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Use of cone beam computed tomography in otolaryngologic treatments.

    PubMed

    Cakli, Hamdi; Cingi, Cemal; Ay, Yazgi; Oghan, Fatih; Ozer, Torun; Kaya, Ercan

    2012-03-01

    Cone beam computed tomography (CBCT) allows us to evaluate 3-dimensional (3D) morphology of the maxillofacial skeleton and also used in dentomaxillofacial imaging to solve complex diagnostic and treatment planning problems such as craniofacial fractures, temporamandibular dysfunctions or sinus imaging. CBCT uses a rectangular or round 2D detector, which allows a single rotation of the gantry to generate a scan of the entire region of interest. Technological and application-specific factors such as development of compact, relatively low-cost, high-quality, large, flat-panel detector arrays; the availability of low-cost computers with processing power sufficient for cone beam image reconstruction; the fabrication of highly efficient radiograph tubes capable of multiple exposures necessary for cone beam scanning at prices lower than those currently used for fan beam CT; and limited volume scanning (e.g., head and neck) eliminating the need for subsecond gantry rotation speeds make this possible. The objective of this study is to review published evidence for CBCT having an important role in ORL treatments. We aimed to review all the available literature about the CBCT imagination in ORL treatments. Systematic literature search was performed using PubMed and Ovid. Additional literature was retrieved from reference lists in the articles. Systematic analysis of the literature from 1998 to 2010 was performed. A total of 40 abstracts were evaluated independently by two members of the project group, and 38 articles were included in the review.

  9. Use of Cone Beam Computed Tomography in Endodontics

    PubMed Central

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

    2009-01-01

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

  10. Fundamentals of cone beam computed tomography for a prosthodontist.

    PubMed

    John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R B

    2015-01-01

    Cone beam computed tomography (CBCT, also referred to as C-arm computed tomography [CT], cone beam volume CT, or flat panel CT) is a medical imaging technique of X-ray CT where the X-rays are divergent, forming a cone.[1] CBCT systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimeter resolution in images of high diagnostic quality, with short scanning times (10-70 s) and radiation dosages reportedly up to 15-100 times lower than those of conventional CT scans. Increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. The aim of this article is to sensitize the Prosthodontist to CBCT technology, provide an overview of currently available maxillofacial CBCT systems and review the specific application of various CBCT display modes to clinical Prosthodontic practice. A MEDLINE search for relevant articles in this specific area of interest was conducted. The selected articles were critically reviewed and the data acquired were systematically compiled.

  11. Incidental Findings on Cone Beam Computed Tomography Images

    PubMed Central

    Allareddy, Veeratrishul; Vincent, Steven D.; Hellstein, John W.; Qian, Fang; Smoker, Wendy R. K.; Ruprecht, Axel

    2012-01-01

    Background. Cone beam computed tomography (CBCT) has gained widespread acceptance in dentistry for a variety of applications. Most dentists who are not radiologists/trained in radiology are generally not familiar with interpretation of anatomical structures and/or pathosis outside their area of primary interest, as often this was not within the scope of their training. Objectives. To assess that the number of incidental findings on a CBCT scan is high both within and outside of the primary area of interest, thereby emphasizing the importance of interpretation of all areas visualized on the scan. Materials and Methods. An oral and maxillofacial radiologist reviewed 1000 CBCT scans (382 males and 618 females) for findings both in- and outside the area of interest. Results. Of the 1000 subjects that were reviewed, 943 scans showed findings in the primary regions of interest and/or outside the regions of interest, and 76 different conditions were visualized in these scans both in and outside the areas of interest. Conclusion. From the wide scope of findings noted on these scans, it can be concluded that it is essential that a person trained in advanced interpretation techniques in radiology interprets cone beam computed tomography scans. PMID:23304148

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

    PubMed Central

    Jaju, Prashant P; Jaju, Sushma P

    2014-01-01

    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. PMID:24729729

  13. Applications of cone beam computed tomography for a prosthodontist.

    PubMed

    John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R B

    2016-01-01

    Cone beam computed tomography (CBCT) is a medical imaging technique of X-ray computed tomography where the X-rays are divergent, forming a cone. CBCT systems have been designed for imaging hard tissues of the maxillofacial region. The increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. This article is intended to elaborate and enunciate on the various applications and benefits of CBCT, in the realm of maxillofacial prosthodontics, over and beyond its obvious benefits in the rehabilitation of patients with implants. With the onus of meticulous reconstruction of near ideal occlusion resting on the prosthodontist, CBCT provides a unique imaging option, which can be a boon in various aspects of prosthodontic practice - from imaging of the temporomandibular joint for accurate movement simulation, to template assisted maxillofacial reconstruction or even over denture therapy. CBCT could play a crucial role in lessening the burden of a hectic prosthodontic routine for the clinician and critically contribute to accurate and effective treatment for the patient. Apart from the authors' clinical experiences shared here, a web-based search for relevant articles in this specific area of interest was also conducted. The selected articles were critically reviewed and the data acquired were systematically compiled.

  14. Applications of cone beam computed tomography for a prosthodontist

    PubMed Central

    John, George Puthenpurayil; Joy, Tatu Elenjickal; Mathew, Justin; Kumar, Vinod R. B.

    2016-01-01

    Cone beam computed tomography (CBCT) is a medical imaging technique of X-ray computed tomography where the X-rays are divergent, forming a cone. CBCT systems have been designed for imaging hard tissues of the maxillofacial region. The increasing availability of this technology provides the dental clinician with an imaging modality capable of providing a three-dimensional representation of the maxillofacial skeleton with minimal distortion. This article is intended to elaborate and enunciate on the various applications and benefits of CBCT, in the realm of maxillofacial prosthodontics, over and beyond its obvious benefits in the rehabilitation of patients with implants. With the onus of meticulous reconstruction of near ideal occlusion resting on the prosthodontist, CBCT provides a unique imaging option, which can be a boon in various aspects of prosthodontic practice – from imaging of the temporomandibular joint for accurate movement simulation, to template assisted maxillofacial reconstruction or even over denture therapy. CBCT could play a crucial role in lessening the burden of a hectic prosthodontic routine for the clinician and critically contribute to accurate and effective treatment for the patient. Apart from the authors’ clinical experiences shared here, a web-based search for relevant articles in this specific area of interest was also conducted. The selected articles were critically reviewed and the data acquired were systematically compiled. PMID:27134420

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

    PubMed Central

    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

  16. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    PubMed

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

    2016-01-01

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

  17. Sodium hypochlorite accident with evaluation by cone beam computed tomography.

    PubMed

    Behrents, K T; Speer, M L; Noujeim, M

    2012-05-01

    To show the radiographic manifestation of sodium hypochlorite after accidental injection past the apical foramen and into the soft tissues. A female patient was seen for an emergency visit after suffering a sodium hypochlorite accident at her general dentist's office. The patient was seen within 1 h of the accident and was in pain associated with facial swelling. Radiographs, including a Cone Beam Computed Tomography (CBCT), and photographs were taken. Endodontic emergency treatment was initiated. The patient was reassured and given pain medication and antibiotics. Follow-up visits were scheduled over 6 days when the swelling had resolved. • Importance of multiple radiographic images during preoperative endodontic evaluation when undertaking endodontic retreatment. • Knowledge of apical anatomy as related to surrounding structures. • Effect of sodium hypochlorite when injected in the soft tissues. © 2012 International Endodontic Journal.

  18. Concrescence: Cone-Beam Computed Tomography Imaging Perspective

    PubMed Central

    Alluri, LeelaSubhashini Choudary; Mallela, Dhiraj

    2016-01-01

    Concrescence is a form of twinning, formed by the confluence of cementum of two teeth at the root level. The diagnosis of concrescence has largely relied on the conventional 2D imaging. The 2D imaging has inherent limitations such as distortion and superimposition. Cone-Beam CT eliminates these limitations. The aim of this article was to describe a case of dental abnormality using Cone-Beam CT imaging modality. Volumetric data demonstrated confluence of left mandibular third molar with a paramolar, a supernumerary tooth. To our knowledge, this is the second case in the dental literature reported demonstrating the use of Cone-Beam CT in the diagnosis of concrescence. PMID:27800194

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

    PubMed

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

    2012-03-01

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

  20. Use of cone beam computed tomography in periodontology.

    PubMed

    Acar, Buket; Kamburoğlu, Kıvanç

    2014-05-28

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

  1. Forensic imaging of projectiles using cone-beam computed tomography.

    PubMed

    von See, Constantin; Bormann, Kai-Hendrik; Schumann, Paul; Goetz, Friedrich; Gellrich, Nils-Claudius; Rücker, Martin

    2009-09-10

    In patients with gunshot injuries, it is easy to detect a projectile within the body due to the high-density of the object, but artefacts make it difficult to obtain information about the deformation and the exact location of the projectile in surrounding tissues. Cone-beam computed tomography (CBCT) is a new radiological imaging modality that allows radio-opaque objects to be localised and assessed in three dimensions. The full potential of the use of CBCT in forensic medicine has not yet been explored. In this study, three different modern projectiles were fired into the heads of pig cadavers (n=6) under standardised conditions. Tissue destruction and the location of the projectiles were analysed separately using CBCT and multi-slice computed tomography (MDCT). The projectiles had the same kinetic energy but showed considerable differences in deformation behaviour. Within the study groups, tissue destruction was reproducible. CBCT is less severely affected by metallic artefacts than MDCT. Therefore CBCT is superior in visualising bone destruction in the immediate vicinity of the projectile and projectile deformation, whereas MDCT allows soft tissue to be evaluated in more detail. CBCT is an improved diagnostic tool for the evaluation of gunshot injuries. In particular, it is superior to MDCT in detecting structural hard-tissue damage in the immediate vicinity of high-density metal projectiles and in identifying the precise location of a projectile in the body.

  2. Can Dental Cone Beam Computed Tomography Assess Bone Mineral Density?

    PubMed Central

    2014-01-01

    Mineral density distribution of bone tissue is altered by active bone modeling and remodeling due to bone complications including bone disease and implantation surgery. Clinical cone beam computed tomography (CBCT) has been examined whether it can assess oral bone mineral density (BMD) in patient. It has been indicated that CBCT has disadvantages of higher noise and lower contrast than conventional medical computed tomography (CT) systems. On the other hand, it has advantages of a relatively lower cost and radiation dose but higher spatial resolution. However, the reliability of CBCT based mineral density measurement has not yet been fully validated. Thus, the objectives of this review are to discuss 1) why assessment of BMD distribution is important and 2) whether the clinical CBCT can be used as a potential tool to measure the BMD. Brief descriptions of image artefacts associated with assessment of gray value, which has been used to account for mineral density, in CBCT images are provided. Techniques to correct local and conversion errors in obtaining the gray values in CBCT images are also introduced. This review can be used as a quick reference for users who may encounter these errors during analysis of CBCT images. PMID:25006568

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

    PubMed

    Pauwels, Ruben; Beinsberger, Jilke; Collaert, Bruno; Theodorakou, Chrysoula; Rogers, Jessica; Walker, Anne; Cockmartin, Lesley; Bosmans, Hilde; Jacobs, Reinhilde; Bogaerts, Ria; Horner, Keith

    2012-02-01

    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. Two Alderson Radiation Therapy anthropomorphic phantoms were loaded with LiF detectors (TLD-100 and TLD-100 H) 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. 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. 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. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  4. Performance studies of four-dimensional cone beam computed tomography

    NASA Astrophysics Data System (ADS)

    Qi, Zhihua; Chen, Guang-Hong

    2011-10-01

    Four-dimensional cone beam computed tomography (4DCBCT) has been proposed to characterize the breathing motion of tumors before radiotherapy treatment. However, when the acquired cone beam projection data are retrospectively gated into several respiratory phases, the available data to reconstruct each phase is under-sampled and thus causes streaking artifacts in the reconstructed images. To solve the under-sampling problem and improve image quality in 4DCBCT, various methods have been developed. This paper presents performance studies of three different 4DCBCT methods based on different reconstruction algorithms. The aims of this paper are to study (1) the relationship between the accuracy of the extracted motion trajectories and the data acquisition time of a 4DCBCT scan and (2) the relationship between the accuracy of the extracted motion trajectories and the number of phase bins used to sort projection data. These aims will be applied to three different 4DCBCT methods: conventional filtered backprojection reconstruction (FBP), FBP with McKinnon-Bates correction (MB) and prior image constrained compressed sensing (PICCS) reconstruction. A hybrid phantom consisting of realistic chest anatomy and a moving elliptical object with known 3D motion trajectories was constructed by superimposing the analytical projection data of the moving object to the simulated projection data from a chest CT volume dataset. CBCT scans with gantry rotation times from 1 to 4 min were simulated, and the generated projection data were sorted into 5, 10 and 20 phase bins before different methods were used to reconstruct 4D images. The motion trajectories of the moving object were extracted using a fast free-form deformable registration algorithm. The root mean square errors (RMSE) of the extracted motion trajectories were evaluated for all simulated cases to quantitatively study the performance. The results demonstrate (1) longer acquisition times result in more accurate motion delineation

  5. Operational principles for cone-beam computed tomography.

    PubMed

    Hatcher, David C

    2010-10-01

    Cone-beam computed tomography (CBCT) was introduced into the U.S. market in 2001. Today, there are more than 3,000 installed units in the United States. There are numerous CBCT manufacturers and types of units. To produce the best imaging results, clinicians need to be knowledgeable about the CBCT unit, the clinical issue being investigated and how to optimize the unit's operational parameters. The author identifies the variables that should be considered for each imaging session and addresses the building blocks required to design the appropriate imaging strategy. The remaining articles in this supplement address imaging for orthodontics, the investigation and localization of impacted teeth and implant planning, and customized imaging protocols designed to solve the clinical issues being presented. The author addresses CBCT from an operational point of view. An ideal imaging examination answers the clinical question while maintaining an acceptable radiation dose and cost. The quality and value of each imaging study is proportional to the protocol being used. The author also addresses imaging protocol variables (raw data frames, scan time, voxel size, field of view and milliampere settings) and their effects on the final image quality and radiation dose, as well as CBCT accuracy and the radiation dose. CBCT can provide image volumes of the maxillofacial region and can be useful in clinical dentistry. CBCT has been shown to be a precise imaging modality and is a valuable tool for use in dental applications. CBCT can be used for diagnosis and treatment planning for all of the dental specialties.

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

    PubMed

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

    2010-10-01

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

  7. Use of dentomaxillofacial cone beam computed tomography in dentistry

    PubMed Central

    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 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, dento-maxillofacial 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. PMID:26120381

  8. Volumetric accuracy of cone-beam computed tomography.

    PubMed

    Park, Cheol-Woo; Kim, Jin-Ho; Seo, Yu-Kyeong; Lee, Sae-Rom; Kang, Ju-Hee; Oh, Song-Hee; Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan

    2017-09-01

    This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Four geometric objects (cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.

  9. EVALUATION OF THYROID RADIATION DOSE USING CONE BEAM COMPUTED TOMOGRAPHY.

    PubMed

    Setti da Rocha, Anna Silvia Penteado; de Mello Aguiar, Guilherme; Tulio, Ana Paula; Ditzel, Alessandra S; Filipov, Danielle

    2017-07-01

    Cone beam computed tomography (CBCT) became common in various dental specialties over the past decade. This technology is used by dental professionals regarding the investigation of maxillofacial structures. Due to the diagnostic quality and possibility of 3D view, this method has become an additional method of human exposure to ionizing radiation. This study aims to evaluate the amount of ionizing radiation absorbed by thyroid gland using CBCT. Measurements were performed by LiF dosimeters (TLD-100), positioned on a phantom for head and neck, which was irradiated by Newtom 3G-CBCT. The average of phantom surface radiation dose at the thyroid gland was 0.48 mGy. The data obtained during this study are suitable to reference values; therefore, it is important to recall that the as low as reasonably achievable principle must be applied in all procedures, thereby safeguarding the patient and also the professional. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Cone Beam Computed Tomography for the Implant Patient

    PubMed Central

    Angelopoulos, Christos; Aghaloo, Tara

    2017-01-01

    Cone beam CT scanning has brought a new dimension to dentistry for the implant patient. In all aspects of diagnosis, treatment planning, surgical preparation and execution, follow-up, and management of complications, we now can treat our patients with increased precision and predictability. However, as with all new technology, we must consider the added cost to the overall treatment and the risks vs. benefits to each individual patient. PMID:21094723

  11. Use of cone beam computed tomography in identifying postmenopausal women with osteoporosis.

    PubMed

    Brasileiro, C B; Chalub, L L F H; Abreu, M H N G; Barreiros, I D; Amaral, T M P; Kakehasi, A M; Mesquita, R A

    2017-12-01

    The aim of this study is to correlate radiometric indices from cone beam computed tomography (CBCT) images and bone mineral density (BMD) in postmenopausal women. Quantitative CBCT indices can be used to screen for women with low BMD.

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

    PubMed

    Drage, Nicholas; Carmichael, Fiona; Brown, Jackie

    2010-10-01

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

  13. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    SciTech Connect

    Sailer, Anna M.; Schurink, Geert Willem H.; Wildberger, Joachim E. Graaf, Rick de Zwam, Willem H. van Haan, Michiel W. de Kemerink, Gerrit J. Jeukens, Cécile R. L. P. N.

    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.

  14. Cone-Beam Computed Tomography-Guided Percutaneous Radiologic Gastrostomy

    SciTech Connect

    Moehlenbruch, Markus; Nelles, Michael; Thomas, Daniel; Willinek, Winfried; Gerstner, Andreas; Schild, Hans H.; Wilhelm, Kai

    2010-04-15

    The purpose of this study was to investigate the feasibility of a flat-detector C-arm-guided radiographic technique (cone-beam computed tomography [CBCT]) for percutaneous radiologic gastrostomy (PRG) insertion. Eighteen patients (13 men and 5 women; mean age 62 years) in whom percutaneous endoscopic gastrostomy (PEG) had failed underwent CBCT-guided PRG insertion. PEG failure or unsuitability was caused by upper gastrointestinal tract obstruction in all cases. Indications for gastrostomy were esophageal and head and neck malignancies, respectively. Before the PRG procedure, initial C-arm CBCT scans were acquired. Three- and 2-dimensional soft-tissue reconstructions of the epigastrium region were generated on a dedicated workstation. Subsequently, gastropexy was performed with T-fasteners after CBCT-guided puncture of the stomach bubble, followed by insertion of an 14F balloon-retained catheter through a peel-away introducer. Puncture of the stomach bubble and PRG insertion was technically successful in all patients without alteration of the epigastric region. There was no malpositioning of the tube or other major periprocedural complications. In 2 patients, minor complications occurred during the first 30 days of follow-up (PRG malfunction: n = 1; slight infection: n = 1). Late complications, which were mainly tube disturbances, were observed in 2 patients. The mean follow-up time was 212 days. CBCT-guided PRG is a safe, well-tolerated, and successful method of gastrostomy insertion in patients in whom endoscopic gastrostomy is not feasible. CBCT provides detailed imaging of the soft tissue and surrounding structures of the epigastric region in one diagnostic tour and thus significantly improves the planning of PRG procedures.

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

    PubMed

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

    2015-02-21

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohua; Ning, Ruola

    2011-03-01

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

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Task-driven imaging in cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Gang, G. J.; Stayman, J. W.; Ouadah, S.; Ehtiati, T.; Siewerdsen, J. H.

    2015-03-01

    Purpose: Conventional workflow in interventional imaging often ignores a wealth of prior information of the patient anatomy and the imaging task. This work introduces a task-driven imaging framework that utilizes such information to prospectively design acquisition and reconstruction techniques for cone-beam CT (CBCT) in a manner that maximizes task-based performance in subsequent imaging procedures. Methods: The framework is employed in jointly optimizing tube current modulation, orbital tilt, and reconstruction parameters in filtered back-projection reconstruction for interventional imaging. Theoretical predictors of noise and resolution relates acquisition and reconstruction parameters to task-based detectability. Given a patient-specific prior image and specification of the imaging task, an optimization algorithm prospectively identifies the combination of imaging parameters that maximizes task-based detectability. Initial investigations were performed for a variety of imaging tasks in an elliptical phantom and an anthropomorphic head phantom. Results: Optimization of tube current modulation and view-dependent reconstruction kernel was shown to have greatest benefits for a directional task (e.g., identification of device or tissue orientation). The task-driven approach yielded techniques in which the dose and sharp kernels were concentrated in views contributing the most to the signal power associated with the imaging task. For example, detectability of a line pair detection task was improved by at least three fold compared to conventional approaches. For radially symmetric tasks, the task-driven strategy yielded results similar to a minimum variance strategy in the absence of kernel modulation. Optimization of the orbital tilt successfully avoided highly attenuating structures that can confound the imaging task by introducing noise correlations masquerading at spatial frequencies of interest. Conclusions: This work demonstrated the potential of a task

  1. Dimensional stability in composite cone beam computed tomography.

    PubMed

    Kopp, S; Ottl, P

    2010-12-01

    An automated increase in the field of view (FOV) for multipurpose cone beam CT (CBCT) by "stitching" (joining) up to three component volumes to yield a larger composite volume must still ensure dimensional stability, especially if the image is to form the basis for a surgical splint. Dimensional stability, image discrepancies and the influence of movement artefacts between exposures were evaluated. The first consumer installation of the Kodak 9000 three-dimensional (3D) extraoral imaging system with stitching software was used for the evaluation of a human mandible with three endodontic instruments as markers. The distances between several reproducible points were measured directly and the results compared with the values measured on screen. Displacements of the mandible along all axes between exposures as well as angular displacements were conducted to test the capability of the system. The standard deviations (SD) of the results for the vertical distances varied between 0.212 mm and 0.409 mm (approximately 1-2 voxels; range, 0.6-1.3 mm) and may be considered the systematic error. The SD of the results for the horizontal and diagonal distances varied between 0.195 mm and 0.571 mm (approximately 1-3 voxels; range, 0.6-1.7 mm) if the group with overall horizontal angulations of 10° and a central rotation of 20° was omitted. In conclusion, the evaluated stitching software is a useful tool to expand the options of combined CBCT with an initial small FOV by allowing a merger of up to three component volumes to yield a larger FOV of about 80 × 80 × 37 mm. The dimensional stability was acceptable when seen in relation to the induced disturbance. Further evaluation of this composite CBCT/digital imaging and communications in medicine system for subsequent splint fabrication may yield promising results.

  2. Dimensional stability in composite cone beam computed tomography

    PubMed Central

    Kopp, S; Ottl, P

    2010-01-01

    An automated increase in the field of view (FOV) for multipurpose cone beam CT (CBCT) by “stitching” (joining) up to three component volumes to yield a larger composite volume must still ensure dimensional stability, especially if the image is to form the basis for a surgical splint. Dimensional stability, image discrepancies and the influence of movement artefacts between exposures were evaluated. The first consumer installation of the Kodak 9000 three-dimensional (3D) extraoral imaging system with stitching software was used for the evaluation of a human mandible with three endodontic instruments as markers. The distances between several reproducible points were measured directly and the results compared with the values measured on screen. Displacements of the mandible along all axes between exposures as well as angular displacements were conducted to test the capability of the system. The standard deviations (SD) of the results for the vertical distances varied between 0.212 mm and 0.409 mm (approximately 1–2 voxels; range, 0.6–1.3 mm) and may be considered the systematic error. The SD of the results for the horizontal and diagonal distances varied between 0.195 mm and 0.571 mm (approximately 1–3 voxels; range, 0.6–1.7 mm) if the group with overall horizontal angulations of 10° and a central rotation of 20° was omitted. In conclusion, the evaluated stitching software is a useful tool to expand the options of combined CBCT with an initial small FOV by allowing a merger of up to three component volumes to yield a larger FOV of about 80 × 80 × 37 mm. The dimensional stability was acceptable when seen in relation to the induced disturbance. Further evaluation of this composite CBCT/digital imaging and communications in medicine system for subsequent splint fabrication may yield promising results. PMID:21062945

  3. Task-driven imaging in cone-beam computed tomography

    PubMed Central

    Gang, G. J.; Stayman, J. W.; Ouadah, S.; Ehtiati, T.; Siewerdsen, J. H.

    2015-01-01

    Purpose Conventional workflow in interventional imaging often ignores a wealth of prior information of the patient anatomy and the imaging task. This work introduces a task-driven imaging framework that utilizes such information to prospectively design acquisition and reconstruction techniques for cone-beam CT (CBCT) in a manner that maximizes task-based performance in subsequent imaging procedures. Methods The framework is employed in jointly optimizing tube current modulation, orbital tilt, and reconstruction parameters in filtered backprojection reconstruction for interventional imaging. Theoretical predictors of noise and resolution relates acquisition and reconstruction parameters to task-based detectability. Given a patient-specific prior image and specification of the imaging task, an optimization algorithm prospectively identifies the combination of imaging parameters that maximizes task-based detectability. Initial investigations were performed for a variety of imaging tasks in an elliptical phantom and an anthropomorphic head phantom. Results Optimization of tube current modulation and view-dependent reconstruction kernel was shown to have greatest benefits for a directional task (e.g., identification of device or tissue orientation). The task-driven approach yielded techniques in which the dose and sharp kernels were concentrated in views contributing the most to the signal power associated with the imaging task. For example, detectability of a line pair detection task was improved by at least three fold compared to conventional approaches. For radially symmetric tasks, the task-driven strategy yielded results similar to a minimum variance strategy in the absence of kernel modulation. Optimization of the orbital tilt successfully avoided highly attenuating structures that can confound the imaging task by introducing noise correlations masquerading at spatial frequencies of interest. Conclusions This work demonstrated the potential of a task

  4. Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy

    PubMed Central

    Brunner, Stephen; Nett, Brian E; Tolakanahalli, Ranjini; Chen, Guang-Hong

    2012-01-01

    X-ray scatter is a significant problem in cone-beam computed tomography when thicker objects and larger cone angles are used, as scattered radiation can lead to reduced contrast and CT number inaccuracy. Advances have been made in x-ray computed tomography (CT) by incorporating a high quality prior image into the image reconstruction process. In this paper, we extend this idea to correct scatter-induced shading artifacts in cone-beam CT image-guided radiation therapy. Specifically, this paper presents a new scatter correction algorithm which uses a prior image with low scatter artifacts to reduce shading artifacts in cone-beam CT images acquired under conditions of high scatter. The proposed correction algorithm begins with an empirical hypothesis that the target image can be written as a weighted summation of a series of basis images that are generated by raising the raw cone-beam projection data to different powers, and then, reconstructing using the standard filtered backprojection algorithm. The weight for each basis image is calculated by minimizing the difference between the target image and the prior image. The performance of the scatter correction algorithm is qualitatively and quantitatively evaluated through phantom studies using a Varian 2100 EX System with an on-board imager. Results show that the proposed scatter correction algorithm using a prior image with low scatter artifacts can substantially mitigate scatter-induced shading artifacts in both full-fan and half-fan modes. PMID:21258140

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

    SciTech Connect

    Chen, Dongmei; Zhu, Shouping Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    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.

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

    PubMed

    Ye, Ivan B; Wang, Ge

    2012-08-06

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

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

    PubMed

    2015-10-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-08-01

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

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

    PubMed

    Geleijns, J; Salvadó Artells, M; de Bruin, P W; Matter, R; Muramatsu, Y; McNitt-Gray, M F

    2009-05-21

    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 (D100). Measurements free in air revealed excellent correspondence between CTDI300air and D100air, 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, D100w and CTDI600w, while CTDI100w substantially underestimates CTDI300w. D100w 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 standard of

  12. 3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification.

    PubMed

    Eliášová, Hana; Dostálová, Taťjana

    3D Multislice and Cone-beam computed tomography (CBCT) in forensic odontology has been shown to be useful not only in terms of one or a few of dead bodies but also in multiple fatality incidents. 3D Multislice and Cone-beam computed tomography and digital radiography were demonstrated in a forensic examination form. 3D images of the skull and teeth were analysed and validated for long ante mortem/post mortem intervals. The image acquisition was instantaneous; the images were able to be optically enlarged, measured, superimposed and compared prima vista or using special software and exported as a file. Digital radiology and computer tomography has been shown to be important both in common criminalistics practices and in multiple fatality incidents. Our study demonstrated that CBCT imaging offers less image artifacts, low image reconstruction times, mobility of the unit and considerably lower equipment cost.

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

    PubMed Central

    Kalyan Chakravarthy, Pishipati Vinayak; Telang, Lahari Ajay; Nerali, Jayashri; Telang, Ajay

    2012-01-01

    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. PMID:23198164

  14. Can cone-beam computed tomography superimposition help orthodontists better understand relapse in surgical patients?

    PubMed

    Porciúncula, Guilherme Machado; Koerich, Leonardo; Eidson, Lindsey; Gandini Junior, Luiz Gonzaga; Gonçalves, João Roberto

    2014-11-01

    This case report describes the interdisciplinary treatment of a 19-year-old Brazilian man with a Class I malocclusion, a hyperdivergent profile, an anterior open bite, and signs of temporomandibular joint internal derangement. The treatment plan included evaluation with a temporomandibular joint specialist and a rheumatologist, orthodontic appliances, and maxillomandibular surgical advancement with counterclockwise rotation. Cone-beam computed tomography images were taken before and after surgery at different times and superimposed at the cranial base to assess the changes after orthognathic surgery and to monitor quantitatively the internal derangement of the temporomandibular joints and surgical relapse. Our protocol can improve the orthodontist's understanding of surgical instability, demonstrate the clinical value of cone-beam computed tomography analysis beyond the multiplanar reconstruction, and guide patient management for the best outcome possible.

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

    PubMed Central

    Silva, Luiz Antonio F.; Barriviera, Mauricio; Januário, Alessandro L.; Bezerra, Ana Cristina B.; Fioravanti, Maria Clorinda S.

    2011-01-01

    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. PMID:22122905

  16. Comparative study of mandibular linear measurements obtained by cone beam computed tomography and digital calipers

    PubMed Central

    Tarazona-Álvarez, Pablo; Romero-Millán, Javier; Peñarrocha-Oltra, David; Fuster-Torres, María Á.; Tarazona, Beatriz

    2014-01-01

    Objectives: Cone beam computed tomography (CBCT) is an innovative dental of imaging system characterized by rapid volumetric imaging with patient exposure to a single dose of radiation. The present study was carried out to compare the linear measurements obtained with CBCT and digital caliper in 20 mandibles from human cadavers. Study design: A total of 4800 linear measurements were measured between different mandibular anatomical points with CBCT and digital caliper. The real measurements were defined as those obtained with the digital caliper. Posteriorly, the mandibles were scanned to obtain the CBCT images, with software-based measurements of the distances. Results: The measurements obtained with the digital caliper were greater. The CBCT technique underestimated distances greater than 100 mm. Conclusions: CBCT allows to obtain linear mandibular anatomical measurements equivalent to those obtained with digital caliper. The differences existing between both methods were clinically acceptable. Key words:Computed tomography, cone beam CT, accuracy, reliability, digital caliper. PMID:25136429

  17. Accuracy and Landmark Error Calculation Using Cone-Beam Computed Tomography–Generated Cephalograms

    PubMed Central

    Grauer, Dan; Cevidanes, Lucia S. H.; Styner, Martin A.; Heulfe, Inam; Harmon, Eric T.; Zhu, Hongtu; Proffit, William R.

    2010-01-01

    Objective To evaluate systematic differences in landmark position between cone-beam computed tomography (CBCT)–generated cephalograms and conventional digital cephalograms and to estimate how much variability should be taken into account when both modalities are used within the same longitudinal study. Materials and Methods Landmarks on homologous cone-beam computed tomographic–generated cephalograms and conventional digital cephalograms of 46 patients were digitized, registered, and compared via the Hotelling T2 test. Results There were no systematic differences between modalities in the position of most landmarks. Three landmarks showed statistically significant differences but did not reach clinical significance. A method for error calculation while combining both modalities in the same individual is presented. Conclusion In a longitudinal follow-up for assessment of treatment outcomes and growth of one individual, the error due to the combination of the two modalities might be larger than previously estimated. PMID:19905853

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

    PubMed

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

    2016-04-07

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2015-12-01

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

  1. Studying the Prevalence and Etiology of Class II Subdivision Malocclusion Utilizing Cone-Beam Computed Tomography

    DTIC Science & Technology

    2013-04-24

    Lackland AFB, TX April 24, 2013 The views expressed in this study are those of the authors and do not reflect the official policy of the United...Cone-Beam Computed Tomography’ 7. Intended publication/meeting: June 2013 8. "Required by" date: 1 July 2013 9. Date of submission for USU approval: 6...June 2013 CHAIR OR DEPARTMENT HEAD APPROVAL 1. Name: Curtis M. Marsh, Col, USAF, DMD 2. School/Dept. : AFPDS/Tri-Service Orthodontic Dental School

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

    PubMed Central

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

    2015-01-01

    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 applications of CBCT in endodontics. PMID:25598804

  3. C-arm cone-beam computed tomography in interventional oncology: technical aspects and clinical applications

    PubMed Central

    Floridi, Chiara; Radaelli, Alessandro; Abi-Jaoudeh, Nadine; Grass, Micheal; Lin, Ming De; Chiaradia, Melanie; Geschwind, Jean-Francois; Kobeiter, Hishman; Squillaci, Ettore; Maleux, Geert; Giovagnoni, Andrea; Brunese, Luca; Wood, Bradford; Carrafiello, Gianpaolo; Rotondo, Antonio

    2014-01-01

    C-arm cone-beam computed tomography (CBCT) is a new imaging technology integrated in modern angiographic systems. Due to its ability to obtain cross-sectional imaging and the possibility to use dedicated planning and navigation software, it provides an informed platform for interventional oncology procedures. In this paper, we highlight the technical aspects and clinical applications of CBCT imaging and navigation in the most common loco-regional oncological treatments. PMID:25012472

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

    PubMed

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

    2014-05-01

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

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

    SciTech Connect

    Ding Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-06-15

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

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

    PubMed Central

    Ding, Huanjun; Ducote, Justin L.; Molloi, Sabee

    2013-01-01

    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. PMID:23718593

  7. 3D Algebraic Iterative Reconstruction for Cone-Beam X-Ray Differential Phase-Contrast Computed Tomography

    PubMed Central

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

    2015-01-01

    Due to the potential of compact imaging systems with magnified spatial resolution and contrast, cone-beam x-ray differential phase-contrast computed tomography (DPC-CT) has attracted significant interest. The current proposed FDK reconstruction algorithm with the Hilbert imaginary filter will induce severe cone-beam artifacts when the cone-beam angle becomes large. In this paper, we propose an algebraic iterative reconstruction (AIR) method for cone-beam DPC-CT and report its experiment results. This approach considers the reconstruction process as the optimization of a discrete representation of the object function to satisfy a system of equations that describes the cone-beam DPC-CT imaging modality. Unlike the conventional iterative algorithms for absorption-based CT, it involves the derivative operation to the forward projections of the reconstructed intermediate image to take into account the differential nature of the DPC projections. This method is based on the algebraic reconstruction technique, reconstructs the image ray by ray, and is expected to provide better derivative estimates in iterations. This work comprises a numerical study of the algorithm and its experimental verification using a dataset measured with a three-grating interferometer and a mini-focus x-ray tube source. It is shown that the proposed method can reduce the cone-beam artifacts and performs better than FDK under large cone-beam angles. This algorithm is of interest for future cone-beam DPC-CT applications. PMID:25775480

  8. Cone-beam computed tomography in the management of dentigerous cyst of the jaws: A report of two cases.

    PubMed

    Vidya, Lakshminarayanan; Ranganathan, Kannan; Praveen, B; Gunaseelan, Rajan; Shanmugasundaram, S

    2013-10-01

    Cone-beam computed tomography (CBCT) is an emerging technology finding application in all branches of dentistry. The current series highlights the application of CBCT in the preoperative assessment of dentigerous cyst of the jaws.

  9. Cone-beam computed tomography in the management of dentigerous cyst of the jaws: A report of two cases

    PubMed Central

    Vidya, Lakshminarayanan; Ranganathan, Kannan; Praveen, B; Gunaseelan, Rajan; Shanmugasundaram, S

    2013-01-01

    Cone-beam computed tomography (CBCT) is an emerging technology finding application in all branches of dentistry. The current series highlights the application of CBCT in the preoperative assessment of dentigerous cyst of the jaws. PMID:24604939

  10. A theoretically exact reconstruction algorithm for helical cone-beam differential phase-contrast computed tomography.

    PubMed

    Li, Jing; Sun, Yi; Zhu, Peiping

    2013-08-21

    Differential phase-contrast computed tomography (DPC-CT) reconstruction problems are usually solved by using parallel-, fan- or cone-beam algorithms. For rod-shaped objects, the x-ray beams cannot recover all the slices of the sample at the same time. Thus, if a rod-shaped sample is required to be reconstructed by the above algorithms, one should alternately perform translation and rotation on this sample, which leads to lower efficiency. The helical cone-beam CT may significantly improve scanning efficiency for rod-shaped objects over other algorithms. In this paper, we propose a theoretically exact filter-backprojection algorithm for helical cone-beam DPC-CT, which can be applied to reconstruct the refractive index decrement distribution of the samples directly from two-dimensional differential phase-contrast images. Numerical simulations are conducted to verify the proposed algorithm. Our work provides a potential solution for inspecting the rod-shaped samples using DPC-CT, which may be applicable with the evolution of DPC-CT equipments.

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

    PubMed

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

    2017-01-01

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

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

    PubMed

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

    2016-08-26

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

  13. Iterative image reconstruction for limited-angle inverse helical cone-beam computed tomography.

    PubMed

    Yu, Wei; Zeng, Li

    2016-01-01

    Helical trajectory satisfying the condition of exact reconstruction, has been widely utilized in the commercial computed tomography (CT). While limited by the scanning environment in some practical applications, the conventional helical cone-beam CT imaging is hard to complete, thus, developing an imaging system suited for long-object may be valuable. Three-dimensional C-arm CT is an innovative imaging technique which has been greatly concerned. Since there is a high degree of freedom of C-arm, more flexible image acquisition trajectories for 3D imaging can be achieved. In this work, a fast iterative reconstruction algorithm based on total variation minimization is developed for a trajectory of limited-angle inverse helical cone-beam CT, which can be applied to detect long-object without slip-ring technology. The experimental results show that the developed algorithm can yield reconstructed images of low noise level and high image quality.

  14. Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography.

    PubMed

    Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

    2016-03-01

    Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations.

  15. Comparison of Tissue Density in Hounsfield Units in Computed Tomography and Cone Beam Computed Tomography

    PubMed Central

    Varshowsaz, Masoud; Goorang, Sepideh; Ehsani, Sara; Azizi, Zeynab; Rahimian, Sepideh

    2016-01-01

    Objectives: Bone quality and quantity assessment is one of the most important steps in implant treatment planning. Different methods such as computed tomography (CT) and recently suggested cone beam computed tomography (CBCT) with lower radiation dose and less time and cost are used for bone density assessment. This in vitro study aimed to compare the tissue density values in Hounsfield units (HUs) in CBCT and CT scans of different tissue phantoms with two different thicknesses, two different image acquisition settings and in three locations in the phantoms. Materials and Methods: Four different tissue phantoms namely hard tissue, soft tissue, air and water were scanned by three different CBCT and a CT system in two thicknesses (full and half) and two image acquisition settings (high and low kVp and mA). The images were analyzed at three sites (middle, periphery and intermediate) using eFilm software. The difference in density values was analyzed by ANOVA and correction coefficient test (P<0.05). Results: There was a significant difference between density values in CBCT and CT scans in most situations, and CBCT values were not similar to CT values in any of the phantoms in different thicknesses and acquisition parameters or the three different sites. The correction coefficients confirmed the results. Conclusions: CBCT is not reliable for tissue density assessment. The results were not affected by changes in thickness, acquisition parameters or locations. PMID:27928239

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

    PubMed

    Cohenca, Nestor; Shemesh, Hagay

    2015-09-01

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

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

    SciTech Connect

    Altunbas, M. C.; Shaw, C. C.; Chen, L.; Lai, C.; Liu, X.; Han, T.; Wang, T.

    2007-07-15

    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.

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

    PubMed Central

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

    2017-01-01

    Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This case report describes the importance of cone beam computed tomographyic (CBCT) imaging during endodontic treatment. A 23 year old woman was referred by her general dental practitioner with the chief complaint of spontaneous pain in her right posterior maxilla. From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis was made and endodontic treatment was suggested to the patient. The patient underwent CBCT examination, and CBCT scan slices revealed seven canals: three mesiobuccal (MB1, MB2, and MB3), two distobuccal (DB1 and DB2), and two palatal (P1 and P2). Canals were successfully treated with reciprocating files and filled using single-cone filling technique. Precise knowledge of root canal morphology and its variation is important during root canal treatment. CBCT examination is an excellent tool for identifying and managing these complex root canal systems. PMID:28194366

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

    PubMed Central

    Ludlow, John B.; Walker, Cameron

    2013-01-01

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

  20. Comparative study of a low-Z cone-beam computed tomography system

    NASA Astrophysics Data System (ADS)

    Roberts, D. A.; Hansen, V. N.; Thompson, M. G.; Poludniowski, G.; Niven, A.; Seco, J.; Evans, P. M.

    2011-07-01

    Computed tomography images have been acquired using an experimental (low atomic number (Z) insert) megavoltage cone-beam imaging system. These images have been compared with standard megavoltage and kilovoltage imaging systems. The experimental system requires a simple modification to the 4 MeV electron beam from an Elekta Precise linac. Low-energy photons are produced in the standard medium-Z electron window and a low-Z carbon electron absorber located after the window. The carbon electron absorber produces photons as well as ensuring that all remaining electrons from the source are removed. A detector sensitive to diagnostic x-ray energies is also employed. Quantitative assessment of cone-beam computed tomography (CBCT) contrast shows that the low-Z imaging system is an order of magnitude or more superior to a standard 6 MV imaging system. CBCT data with the same contrast-to-noise ratio as a kilovoltage imaging system (0.15 cGy) can be obtained in doses of 11 and 244 cGy for the experimental and standard 6 MV systems, respectively. Whilst these doses are high for everyday imaging, qualitative images indicate that kilovoltage like images suitable for patient positioning can be acquired in radiation doses of 1-8 cGy with the experimental low-Z system.

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

    PubMed Central

    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

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

    PubMed

    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.

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

    PubMed

    Wang, Hu

    2015-08-01

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

  4. Three-dimensional cephalometry: spiral multi-slice vs cone-beam computed tomography.

    PubMed

    Swennen, Gwen R J; Schutyser, Filip

    2006-09-01

    Three-dimensional (3D) craniofacial imaging techniques are becoming increasingly popular and have opened new possibilities for orthodontic assessment, treatment, and follow-up. Recently, a new 3D cephalometric method based on spiral multi-slice (MS) computed tomography (CT) was developed and validated by our research group. This innovative 3D virtual approach is a bridge between conventional cephalometry and modern craniofacial imaging techniques and provides high-quality, accurate, and reliable quantitative 3D data. The aim of this article was to describe the advantages and the disadvantages of spiral MS-CT 3D cephalometry and to discuss the potential of cone-beam CT 3D cephalometry.

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

    PubMed

    Cohenca, Nestor; Shemesh, Hagay

    2015-06-01

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

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

    PubMed Central

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

    2016-01-01

    Although intraoral radiographs still remain the imaging method of choice for the evaluation of endodontic patients, in recent years, the utilization of cone beam computed tomography (CBCT) in endodontics showed a significant jump. This case series presentation shows the importance of CBCT aided diagnosis and treatment of complex endodontic cases such as; root resorption, missed extra canal, fusion, oblique root fracture, 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

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

    PubMed

    Pradeep, K; Charlie, M; Kuttappa, M A; Rao, Prasana Kumar

    2012-01-01

    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).

  8. Stafne bone cavity and cone-beam computed tomography: a report of two cases.

    PubMed

    Venkatesh, Elluru

    2015-06-01

    In 1942 Stafne reported 35 asymptomatic, radiolucent cavities that were unilaterally located in the posterior region of the mandible between the mandibular angle and the third molar, and below the mandibular canal. The term Stafne bone cavity (SBC) is now used for such asymptomatic lingual bone depressions of the lower jaw. Since then there have been many reports of SBCs but very fews tudies have used cone-beam computed tomography (CBCT) for their diagnosis. The aim of this paper is to describe the clinical and radiological characteristics of two cases of SBCs and the importance of limited CBCT in confirming the diagnosis.

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

    PubMed

    Jaju, Prashant P; Jaju, Sushma P

    2015-12-01

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

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

    PubMed Central

    Jaju, Sushma P.

    2015-01-01

    Cone-beam computed tomography (CBCT) is routinely recommended for dental diagnosis and treatment planning. CBCT exposes patients to less radiation than does conventional CT. Still, lack of proper education among dentists and specialists is resulting in improper referral for CBCT. In addition, aiming to generate high-quality images, operators may increase the radiation dose, which can expose the patient to unnecessary risk. This letter advocates appropriate radiation dosing during CBCT to the benefit of both patients and dentists, and supports moving from the concept of "as low as reasonably achievable" (ALARA) to "as low as diagnostically acceptable" (ALADA). PMID:26730375

  11. Composite modulation transfer function evaluation of a cone beam computed tomography breast imaging system

    NASA Astrophysics Data System (ADS)

    Betancourt-Benítez, Ricardo; Ning, Ruola; Liu, Shaohua

    2009-11-01

    Several factors during the scanning process, image reconstruction and geometry of an imaging system, influence the spatial resolution of a computed tomography imaging system. In this work, the spatial resolution of a state of the art flat panel detector-based cone beam computed tomography breast imaging system is evaluated. First, scattering, exposure level, voltage, voxel size, pixel size, back-projection filter, reconstruction algorithm, and number of projections are varied to evaluate their effect on spatial resolution. Second, its uniformity throughout the whole field of view is evaluated as a function of radius along the x-y plane and as a function of z at the center of rotation. The results of the study suggest that the modulation transfer function is mainly influenced by the pixel, back-projection filter, and number of projections used. The evaluation of spatial resolution throughout the field of view also suggests that this imaging system does have a 3-D quasi-isotropic spatial resolution in a cylindrical region of radius equal to 40 mm centered at the axis of rotation. Overall, this study provides a useful tool to determine the optimal parameters for the best possible use of this cone beam computed tomography breast imaging system.

  12. Motion correction for improved target localization with on-board cone-beam computed tomography.

    PubMed

    Li, T; Schreibmann, E; Yang, Y; Xing, L

    2006-01-21

    On-board imager (OBI) based cone-beam computed tomography (CBCT) has become available in radiotherapy clinics to accurately identify the target in the treatment position. However, due to the relatively slow gantry rotation (typically about 60 s for a full 360 degrees scan) in acquiring the CBCT projection data, the patient's respiratory motion causes serious problems such as blurring, doubling, streaking and distortion in the reconstructed images, which heavily degrade the image quality and the target localization. In this work, we present a motion compensation method for slow-rotating CBCT scans by incorporating into image reconstruction a patient-specific motion model, which is derived from previously obtained four-dimensional (4D) treatment planning CT images of the same patient via deformable registration. The registration of the 4D CT phases results in transformations representing a temporal sequence of three-dimensional (3D) deformation fields, or in other words, a 4D model of organ motion. The algorithm was developed heuristically in two-dimensional (2D) parallel-beam geometry and extended to 3D cone-beam geometry. By simulations with digital phantoms capable of translational motion and other complex motion, we demonstrated that the algorithm can reduce the motion artefacts locally, and restore the tumour size and shape, which may thereby improve the accuracy of target localization and patient positioning when CBCT is used as the treatment guidance.

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

    PubMed Central

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

    2017-01-01

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

  14. Influence of enhancement filters in apical bone loss measurement: A cone-beam computed tomography study.

    PubMed

    de Sousa, Emerson-Tavares; Pinheiro, Mayara-Abreu; Maciel, Patrícia-Pereira; Sales, Marcelo-Augusto-Oliveira

    2017-04-01

    The use of cone-beam computed tomography images (CBCT) providing a better assessment of bone injuries, although the sensibility of lesions measurement might be improved by the use of enhancement filters. Objective: This study aimed to analyze the influence of enhancement filters in apical bone loss measurement. Eighteen CBCT cases randomly selected of apical bone loss were evaluated. The analyses were carried out following the evaluation in axial, coronal and sagittal protocols, using enhancement filters as Hard, Normal, and Very Sharp. The variables were statistically analyzed by Friedman and Wilcoxon test, Spearman's rho, and intraclass correlation coefficient. The differences between filters in axial and sagittal protocols were significant (p<0.05); however, this was not observed in the coronal slice. The use of Hard filter demonstrates better results than Very Sharp and Normal filter, improving significantly the bone loss measurement. A strong, significant and positive correlation was noted for all filters (with p< 0.001), such as a strong agreement between the variables, when the Normal filter was used as a reference. The use of enhancement filters increases the sensitivity of alveolar bone loss measurement, with relative advantage for Hard filter. Key words:Cone-Beam computed tomography. endodontics. periapical periodontitis. image enhancement. alveolar bone loss.

  15. Parallel computing methods for x-ray cone beam tomography with large array sizes

    SciTech Connect

    Reimann, D.A. ||; Flynn, M.J.; Sethi, I.K.

    1996-12-31

    Cone beam geometries are increasingly of interest for x-ray CT applications to improve imaging efficiency. In this paper, we describe our practical experience implementing circular orbit cone beam backprojection on workstation clusters. The reconstruction problem is computationally intensive, particularly for arrays of 512 voxels; in each direction. A voxel driven approach is described where the reconstruction volume is partitioned into variable width slabs and each slab given to a workstation. Each projection is filtered by one workstation and then sent to the others for backprojection. While most computation is done in the backprojection step, a significant amount of time must be spent in sending projectional data. A method is detailed to further reduce the communication overhead by restricting the amount of projection sent to only what is required by each backprojecting workstation. Furthermore, if the shape of the backprojection slabs is made as square as possible, the total communication requirement can be minimized. By the reduction of communication requirement, an overall improvement in processor utilization was observed, and the crossover point where communications dominates was improved.

  16. Evaluation of mandibular volume classified by vertical skeletal dimensions with cone-beam computed tomography.

    PubMed

    Nakawaki, Takatoshi; Yamaguchi, Tetsutaro; Tomita, Daisuke; Hikita, Yu; Adel, Mohamed; Katayama, Koshu; Maki, Koutaro

    2016-11-01

     To investigate the relationship between anteroposterior and vertical differences in maxillofacial morphology and mandibular volume.  Subjects comprised 213 Japanese adults (84 males and 129 females) who were divided into three groups based on mandibular basal arch (ANB) and Wits, measured in a cephalometric analysis: Class I (-1° ≤ ANB < 4°,-1 mm ≤ Wits < 0 mm), Class II (ANB ≥ 4°, Wits ≥ 0), and Class III (ANB <-1°, Wits <-1 mm). Subjects were also divided into three groups based on the mandibular plane angle (Mp), as follows: hypodivergent (Mp < 23°), normodivergent (Mp  =  23-30°), and hyperdivergent (Mp > 30°) groups. Mandibular volume was measured from cone-beam computed tomographic images that were analyzed using Analyze™ image processing software and compared among the three groups in each classification.  No significant differences were noted in mandibular volume among Classes I, II, and III. An inverse relationship was found between mandibular volume and Mp, and a significant difference was noted in mandibular volume between the hypodivergent and hyperdivergent groups.  In addition to two-dimensional analysis, such as lateral cephalometry, three-dimensional information such as volume, provided by cone-beam computed tomography, contributes to a more detailed assessment of maxillofacial morphology.

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

    PubMed

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

    2016-07-21

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

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

    PubMed Central

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

    2009-01-01

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

  19. Characteristics of anatomical landmarks in the mandibular interforaminal region: A cone-beam computed tomography study

    PubMed Central

    Parnia, Fereidoun; Hafezeqoran, Ali; Mahboub, Farhang; Mojaver-Kahnamoui, Haniye

    2012-01-01

    Objectives: This study was conducted to assess appearance, visibility, location and course of anatomical landmarks in mandibular interforaminal region using cone-beam computed tomography (CBCT). Study design: A total of 96 CBCT examinations was re-evaluated to exploit anatomical landmarks. The examinations used the Promax 3D CBCT unit. A sole examiner carried out all the measurements. Visibilities of the anatomical landmarks were scored using a four-point rating scale. Results: The mandibular foramen, anterior loop, incisive canal and lingual foramen were observed in 100,84,83,49 % of the images, respectively. The mean size, diameter and width of anterior loop, incisive canal and lingual foramen were obtained 3.54± 1.41, 1.47±0.50 and 0.8 ± 0.09mm, respectively. Conclusion: It is not safe to recommend any definite distance mesially from the mental foramen. The diameter of the canals and foramens should be determined on a case-by-case basis to exploit the appropriate location for each individual. Key words:Anatomical landmarks, cone-beam computed tomography, implant surgery, radiographic evaluation, surgical complications. PMID:22143718

  20. Frequency of Root Canal Isthmi in Human Permanent Teeth Determined by Cone-beam Computed Tomography.

    PubMed

    Estrela, Carlos; Rabelo, Luiz Eduardo G; de Souza, João Batista; Alencar, Ana Helena G; Estrela, Cyntia R A; Sousa Neto, Manoel Damião; Pécora, Jesus Djalma

    2015-09-01

    This study evaluated the frequency of root canal isthmi (RCIs) in human permanent teeth by using cone-beam computed tomography. A sample of 1400 teeth of 618 patients (394 women; mean age, 43.4 years) was selected. RCIs were detected longitudinally on 0.1-mm/0.1-mm axial slices of cone-beam computed tomography images of roots scanned from the pulp orifice to the apex, and findings were classified into 7 categories according to RCIs beginning and end: (1) both in the cervical third, (2) begin in the cervical third and end in the middle third, (3) begin in the cervical third and end in the apical third, (4) both in the middle third, (5) begin in the middle third and end in the apical third, (6) both in the apical third, or (7) no isthmus. A χ(2) test with Yates correction or the Fisher exact test was used to analyze categorical variables, described as frequencies (%). The Student t test was used to compare quantitative variables. RCI is a common anatomic structure in human permanent teeth, except in maxillary anterior teeth. The higher frequencies of RCIs (87.9%) were found in mandibular first molars. The frequencies of RCIs according to mean age and tooth group were not significantly different (P > .05), except in mandibular central incisors. RCIs were less frequent among older patients. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Computer-aided diagnosis of periapical cyst and keratocystic odontogenic tumor on cone beam computed tomography.

    PubMed

    Yilmaz, E; Kayikcioglu, T; Kayipmaz, S

    2017-07-01

    In this article, we propose a decision support system for effective classification of dental periapical cyst and keratocystic odontogenic tumor (KCOT) lesions obtained via cone beam computed tomography (CBCT). CBCT has been effectively used in recent years for diagnosing dental pathologies and determining their boundaries and content. Unlike other imaging techniques, CBCT provides detailed and distinctive information about the pathologies by enabling a three-dimensional (3D) image of the region to be displayed. We employed 50 CBCT 3D image dataset files as the full dataset of our study. These datasets were identified by experts as periapical cyst and KCOT lesions according to the clinical, radiographic and histopathologic features. Segmentation operations were performed on the CBCT images using viewer software that we developed. Using the tools of this software, we marked the lesional volume of interest and calculated and applied the order statistics and 3D gray-level co-occurrence matrix for each CBCT dataset. A feature vector of the lesional region, including 636 different feature items, was created from those statistics. Six classifiers were used for the classification experiments. The Support Vector Machine (SVM) classifier achieved the best classification performance with 100% accuracy, and 100% F-score (F1) scores as a result of the experiments in which a ten-fold cross validation method was used with a forward feature selection algorithm. SVM achieved the best classification performance with 96.00% accuracy, and 96.00% F1 scores in the experiments in which a split sample validation method was used with a forward feature selection algorithm. SVM additionally achieved the best performance of 94.00% accuracy, and 93.88% F1 in which a leave-one-out (LOOCV) method was used with a forward feature selection algorithm. Based on the results, we determined that periapical cyst and KCOT lesions can be classified with a high accuracy with the models that we built using

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

    SciTech Connect

    Ruschin, Mark; Komljenovic, Philip T.; Ansell, Steve; Menard, Cynthia; Bootsma, Gregory; Cho, Young-Bin; Chung, Caroline; Jaffray, David

    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

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

    SciTech Connect

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

    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.

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

    PubMed

    Akgül, N; Caglayan, F; Durna, N; Sümbüllü, M-A; Akgül, H-M; Durna, D

    2012-03-01

    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. 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 with Pearson chi-squared test. Enamel pearls were detected in 36 subjects (4.69%). Of these enamel pearls, 19 were detected in male and 17 were in male. There was no statistically a significant association between prevalence of enamel pearls and sex. All of enamel pearls were detected in molar teeth, for prevalence 0.83%. All of enamel pearls are found upper and lower molar teeth, especially the most commonly in maxillary second and third molars.

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2009-01-01

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

  7. Prospects and challenges of rendering tissue density in Hounsfield units for cone beam computed tomography.

    PubMed

    Molteni, Roberto

    2013-07-01

    Limitations in rendering of tissue density in Hounsfield units (HUs) for cone beam computed tomography (CBCT) are described and illustrated using a phantom and two CBCT systems to demonstrate grayscale measurement variability. The basis of the HU scale, its correlation with measured computed tomography (CT) numbers, and the limitations in the accuracy of such correlation due to artifacts are discussed. Rendering of tissue densities based on HU values of two CBCT systems [NewTom VGi and Hyperion X9, respectively large and small field of view (FOV)] are measured using a phantom. Data produced from small FOV CBCT acquisition are generally less affected by artifacts compared with large FOV CBCT. Artifacts challenge the accurate conversion of density values into HUs. Care should be taken when interpreting quantitative density measurements obtained with CBCT. With more advanced software and methods, it may be possible to improve the consistency and accuracy of density measurements. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. High-quality image acquisition by double exposure overlap in dental cone beam computed tomography.

    PubMed

    Plachtovics, Mark; Bujtar, Peter; Nagy, Katalin; Mommaerts, Maurice

    2014-06-01

    With a double exposure overlapping cone beam computed tomography (CBCT) scan technique, using CBCT acquisition radiation dose, the objective was to obtain apparent density similar to that of multidetector computed tomography (MDCT). Factory quality-assurance phantom and water phantom were used for the evaluation of apparent density fidelity of iCAT scans in different modes. Each scan's apparent density was analyzed for identical regions using ImageJ, version 1.42q. The iCAT Classic extended height acquisition with 4-cm central overlap and reconstruction of 2 groups of 300 projections per rotation for the water and quality-assurance CBCT phantoms resulted in improved apparent density fidelity. This apparent density accuracy was superior to that of iCAT scan at high resolution (600 projections during 1 rotation). Using double exposure overlapping CBCT scans allows the analysis quality to be comparable with that of MDCT. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    PubMed

    Li, Xiang; Li, Tianfang; Yang, Yong; Heron, Dwight E; Huq, M Saiful

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2013-09-01

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

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

    PubMed

    Karimi, Davood; Ward, Rabab

    2016-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Li, Tianfang; Yang, Yong; Heron, Dwight E.; Saiful Huq, M.

    2011-05-01

    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.

  14. Characteristics of kilovoltage x-ray beams used for cone-beam computed tomography in radiation therapy.

    PubMed

    Ding, George X; Duggan, Dennis M; Coffey, Charles W

    2007-03-21

    The purpose of this investigation is to characterize the beams produced by a kilovoltage (kV) imager integrated into a linear accelerator (Varian on-board imager integrated into the Trilogy accelerator) for acquiring high resolution volumetric cone-beam computed tomography (CBCT) images of the patient on the treatment table. The x-ray tube is capable of generating photon spectra with kVp values between 40 and 125 kV. The Monte Carlo simulations were used to study the characteristics of kV beams and the properties of imaged target scatters. The Monte Carlo results were benchmarked against measurements, and excellent agreements were obtained. We also studied the effect of including the electron impact ionization (EII), and the simulation showed that the characteristic radiation is increased significantly in the energy spectra when EII is included. Although only slight beam hardening is observed in the spectra of all photons after passing through the phantom target, there is a significant difference in the spectra and angular distributions between scattered and primary photons. The results also show that the photon fluence distributions are significantly altered by adding bow tie filters. The results indicate that a combination of large cone-beam field size and large imaged target significantly increases scatter-to-primary ratios for photons that reach the detector panel. For phantoms 10 cm, 20 cm and 30 cm thick of water placed at the isocentre, the scatter-to-primary ratios are 0.94, 3.0 and 7.6 respectively for an open 125 kVp CBCT beam. The Monte Carlo simulations show that the increase of the scatter is proportional to the increase of the imaged volume, and this also applies to scatter-to-primary ratios. This study shows both the magnitude and the characteristics of scattered x-rays. The knowledge obtained from this investigation may be useful in the future design of the image detector to improve the image quality.

  15. Characteristics of kilovoltage x-ray beams used for cone-beam computed tomography in radiation therapy

    NASA Astrophysics Data System (ADS)

    Ding, George X.; Duggan, Dennis M.; Coffey, Charles W.

    2007-03-01

    The purpose of this investigation is to characterize the beams produced by a kilovoltage (kV) imager integrated into a linear accelerator (Varian on-board imager integrated into the Trilogy accelerator) for acquiring high resolution volumetric cone-beam computed tomography (CBCT) images of the patient on the treatment table. The x-ray tube is capable of generating photon spectra with kVp values between 40 and 125 kV. The Monte Carlo simulations were used to study the characteristics of kV beams and the properties of imaged target scatters. The Monte Carlo results were benchmarked against measurements, and excellent agreements were obtained. We also studied the effect of including the electron impact ionization (EII), and the simulation showed that the characteristic radiation is increased significantly in the energy spectra when EII is included. Although only slight beam hardening is observed in the spectra of all photons after passing through the phantom target, there is a significant difference in the spectra and angular distributions between scattered and primary photons. The results also show that the photon fluence distributions are significantly altered by adding bow tie filters. The results indicate that a combination of large cone-beam field size and large imaged target significantly increases scatter-to-primary ratios for photons that reach the detector panel. For phantoms 10 cm, 20 cm and 30 cm thick of water placed at the isocentre, the scatter-to-primary ratios are 0.94, 3.0 and 7.6 respectively for an open 125 kVp CBCT beam. The Monte Carlo simulations show that the increase of the scatter is proportional to the increase of the imaged volume, and this also applies to scatter-to-primary ratios. This study shows both the magnitude and the characteristics of scattered x-rays. The knowledge obtained from this investigation may be useful in the future design of the image detector to improve the image quality.

  16. Evaluation of artifacts generated by zirconium implants in cone-beam computed tomography images.

    PubMed

    Vasconcelos, Taruska Ventorini; Bechara, Boulos B; McMahan, Clyde Alex; Freitas, Deborah Queiroz; Noujeim, Marcel

    2017-02-01

    To evaluate zirconium implant artifact production in cone beam computed tomography images obtained with different protocols. One zirconium implant was inserted in an edentulous mandible. Twenty scans were acquired with a ProMax 3D unit (Planmeca Oy, Helsinki, Finland), with acquisition settings ranging from 70 to 90 peak kilovoltage (kVp) and voxel sizes of 0.32 and 0.16 mm. A metal artifact reduction (MAR) tool was activated in half of the scans. An axial slice through the middle region of the implant was selected for each dataset. Gray values (mean ± standard deviation) were measured in two regions of interest, one close to and the other distant from the implant (control area). The contrast-to-noise ratio was also calculated. Standard deviation decreased with greater kVp and when the MAR tool was used. The contrast-to-noise ratio was significantly higher when the MAR tool was turned off, except for low resolution with kVp values above 80. Selection of the MAR tool and greater kVp resulted in an overall reduction of artifacts in images acquired with low resolution. Although zirconium implants do produce image artifacts in cone-bean computed tomography scans, the setting that best controlled artifact generation by zirconium implants was 90 kVp at low resolution and with the MAR tool turned on. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Laser cone beam computed tomography scanner geometry for large volume 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Jordan, K. J.; Turnbull, D.; Batista, J. J.

    2013-06-01

    A new scanner geometry for fast optical cone-beam computed tomography is reported. The system consists of a low power laser beam, raster scanned, under computer control, through a transparent object in a refractive index matching aquarium. The transmitted beam is scattered from a diffuser screen and detected by a photomultiplier tube. Modest stray light is present in the projection images since only a single ray is present in the object during measurement and there is no imaging optics to introduce further stray light in the form of glare. A scan time of 30 minutes was required for 512 projections with a field of view of 12 × 18 cm. Initial performance from scanning a 15 cm diameter jar with black solutions is presented. Averaged reconstruction coefficients are within 2% along the height of the jar and within the central 85% of diameter, due to the index mismatch of the jar. Agreement with spectrometer measurements was better than 0.5% for a minimum transmission of 4% and within 4% for a dark, 0.1% transmission sample. This geometry's advantages include high dynamic range and low cost of scaling to larger (>15 cm) fields of view.

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

    PubMed Central

    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

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

    PubMed

    Li, Gang

    2013-06-01

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

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

    PubMed

    Rosen, E; Tsesis, I

    2016-01-01

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

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

    PubMed Central

    Park, Young-Seok; Ahn, Jin-Soo; Kwon, Ho-Beom

    2011-01-01

    Purpose The purpose of this article is to review the current status of dental caries diagnosis using cone beam computed tomography (CBCT). Materials and Methods An online PubMed search was performed to identify studies on caries research using CBCT. Results 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. Conclusion 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. PMID:21977474

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed Central

    Pasha, Shiraz; Chaitanya, Bathula Vimala; Somisetty, Kusum Valli

    2016-01-01

    Root canal treatment of tooth with aberrant root canal morphology is very challenging. So thorough knowledge of both the external and internal anatomy of teeth is an important aspect of root canal treatment. With the advancement in technology it is imperative to use modern diagnostic tools such as magnification devices, CBCT, microscopes, and RVG to confirm the presence of these aberrant configurations. However, in everyday endodontic practice, clinicians have to treat teeth with atypical configurations for root canal treatment to be successful. This case report presents the management of a mandibular first molar with six root canals, four in mesial and two in distal root, and also emphasizes the use and importance of Cone Beam Computed Tomography (CBCT) as a diagnostic tool in endodontics. PMID:26904310

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

    PubMed Central

    Phulambrikar, Tushar; Vilas Kant, Sanchita; Kode, Manasi; Magar, Shaliputra

    2015-01-01

    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. PMID:26636128

  5. Responsible use of cone beam computed tomography: minimising medico-legal risks.

    PubMed

    Noffke, C E E; Farman, A G; Van der Linde, A; Nel, S

    2013-07-01

    This communication highlights some of the ethical and possible legal responsibilities which pertain to the taking, reading, reporting, and communication of findings from cone-beam computed tomography (CBCT) scans. The importance of knowledge of head and neck anatomy and pathology to reduce the likelihood of incorrect interpretation is emphasised. Failure to detect critical findings in any diagnostic image can potentially result in medico-legal consequences. CBCT is no exception to this rule. Dental schools are advised to include CBCT imaging as a diagnostic tool in their under- and postgraduate curricula thereby equipping graduates to use 3D imaging in general and CBCT in particular. Existing dental practitioners are advised to seek continuing education on 3D imaging as part of their required lifelong learning.

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

    PubMed Central

    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 slight swelling in the left mandible. Surgical resection was performed. No recurrence was noted. In the CBCT sections, we observed perforation of the cortical plate and radiopaque line that extended from the periosteum, resembling "sunray" appearance—a rare feature of OM—which could not be assessed by panoramic radiography. PMID:27092217

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

    PubMed Central

    Chen, Christine A.; Ahn, Yoonhee; Odell, Scott; Graham, David Mattew

    2016-01-01

    A static, unilateral, and focal bone depression located lingually within the ascending ramus, identical to the Stafne's bone cavity of the angle of the mandible, is being reported. During development of the mandible, submandibular gland inclusion may lead to the formation of a lingual concavity, which could contain fatty tissue, blood vessels, or soft tissue. However, similar occurrences in the ascending ramus at the level of the parotid gland are extremely rare. Similar cases were previously reported in dry, excavated mandibles, and 3 cases were reported in living patients. A 52-year-old African American male patient was seen for pain in the mandibular teeth. Panoramic radiography showed an unusual concavity within the left ascending ramus. Cone-beam computed tomography confirmed this incidental finding. The patient was cleared for the extraction of non-restorable teeth and scheduled for annual follow-up. PMID:27672619

  8. Evaluation of Dose Homogeneity in Cone-Beam Breast Computed Tomography.

    PubMed

    Mettivier, Giovanni; Costa, Matilde; Lanconelli, Nico; Ianiro, Anna; Pugliese, Mariagabriella; Quarto, Maria; Russo, Paolo

    2017-01-10

    The aim of this study is to determine, via measurements on phantoms and Monte Carlo (MC) simulations, the dose distribution of absorbed dose in a cone-beam breast computed tomography scan. The absorbed dose volume distribution was measured inside a polyethylene cylindrical phantom, simulating adipose breast tissue, using LiF:Mg,Ti thermoluminescence dosimeters. A reasonable agreement (between 2 and 8%) between the simulated and measured data was observed. The 3D distribution of absorbed dose was evaluated at 40, 60 and 80 kV in a phantom simulating a pendant breast. MC simulations indicate a significantly lower spread of volume dose than in mammography. The dose variation along the radial distance in the simulated phantoms was in the range of 4‒14%. These findings might be useful when devising models for breast imaging dose assessment that take into account the uneven distribution of the glandular mass in the breast volume.

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

    PubMed

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

    2015-09-01

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

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

    PubMed Central

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

    2015-01-01

    Supernumerary teeth are extra teeth or toothlike structures which may have either erupted or unerupted in addition to the 20 deciduous teeth and the 32 permanent teeth. Mesiodens is one of these located in the midline between the two central incisors. Their presence may give rise to a variety of clinical problems. This paper describes a rare case of palatal placed, inverted and impacted mesiodens associated to two supernumerary teeth which were detected during a radiographic examination for delayed eruption of permanent central incisors in the case of a healthy 8-year-old girl monitored at the oral surgery service while discussing the usefulness of cone beam computed tomography for accurate diagnosis and management. PMID:26604591

  11. Rare Root Canal Configuration of Bilateral Maxillary Second Molar Using Cone-beam Computed Tomographic Scanning.

    PubMed

    Zeng, Chang; Shen, Ya; Guan, Xiaoyue; Wang, Xin; Fan, Mingwen; Li, Yuhong

    2016-04-01

    The aim of this article was to present a right maxillary second molar with an unusual root canal morphology of 4 roots and 5 canals as confirmed by cone-beam computed tomographic (CBCT) imaging. The tooth had a C-shaped mesiobuccal root (CBCT imaging revealed that the root was closer to the palate than the buccal side) with 2 canals, 2 fused distobuccal roots with 2 separate canals, and 1 normal bulky palatal root with 1 canal. After thoroughly examining the rare anatomy, root canal treatment was applied on the tooth. This article shows the complexity of maxillary second molar variation and shows the significance of CBCT imaging in the confirmation of the 3-dimensional anatomy of teeth and endodontic treatment. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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

    PubMed

    Cheng, Harry C Y; Wu, Vincent W C; Liu, Eva S F; Kwong, Dora L W

    2011-05-01

    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. A calibrated Farmer chamber and two standard cylindrical Perspex CT dosimetry phantoms with diameter of 16 cm (head phantom) and 32 cm (body phantom) were used to measure the weighted cone-beam computed tomography dose index (CBCTDIw) of the Varian CBCT system. The absorbed dose of different organs was measured in a female anthropomorphic phantom with thermoluminescent dosimeters (TLD) and the total effective dose was estimated according to International Commission on Radiological Protection (ICRP) Publication 103. The dose measurement and image quality were studied for head-and-neck and pelvic regions, and comparison was made between the new and old protocols. The values of the new CBCTDIw head-and-neck and pelvic protocols were 36.6 and 29.4 mGy, respectively. The total effective doses from the new head-and-neck and pelvic protocols were 1.7 and 8.2 mSv, respectively. The absorbed doses of lens for the new 200° and old 360° head-and-neck protocols were 3.8 and 59.4 mGy, respectively. The additional secondary cancer risk from daily CBCT might be up to 2.8%. The new Varian CBCT provided volumetric information for image guidance with acceptable image quality and lower radiation dose. This imaging tool gave a better standard for patient daily setup verification. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    PubMed

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

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

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

    PubMed

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

    2016-09-24

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

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

    PubMed

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

    2009-01-01

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

  16. C-arm Cone Beam Computed Tomographic Needle Path Overlay for Fluoroscopic-Guided Placement of Translumbar Central Venous Catheters

    SciTech Connect

    Tam, Alda; Mohamed, Ashraf; Pfister, Marcus; Rohm, Esther; Wallace, Michael J.

    2009-07-15

    C-arm cone beam computed tomography is an advanced 3D imaging technology that is currently available on state-of-the-art flat-panel-based angiography systems. The overlay of cross-sectional imaging information can now be integrated with real-time fluoroscopy. This overlay technology was used to guide the placement of three percutaneous translumbar inferior vena cava catheters.

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

    NASA Astrophysics Data System (ADS)

    Lawless, Michael J.

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

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

    PubMed Central

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

    2015-01-01

    Cone beam computed tomography (CBCT) systems with rotational gantries that have standard flat panel detectors (FPD) are widely used for the 3D rendering of vascular structures using Feldkamp cone beam reconstruction algorithms. One of the inherent limitations of these systems is limited resolution (<3 lp/mm). There are systems available with higher resolution but their small FOV limits them to small animal imaging only. In this work, we report on region-of-interest (ROI) CBCT with a high resolution CMOS detector (75 μm pixels, 600 μm HR-CsI) mounted with motorized detector changer on a commercial FPD-based C-arm angiography gantry (194 μm pixels, 600 μm HL-CsI). A cylindrical CT phantom and neuro stents were imaged with both detectors. For each detector a total of 209 images were acquired in a rotational protocol. The technique parameters chosen for the FPD by the imaging system were used for the CMOS detector. The anti-scatter grid was removed and the incident scatter was kept the same for both detectors with identical collimator settings. The FPD images were reconstructed for the 10 cm x10 cm FOV and the CMOS images were reconstructed for a 3.84 cm × 3.84 cm FOV. Although the reconstructed images from the CMOS detector demonstrated comparable contrast to the FPD images, the reconstructed 3D images of the neuro stent clearly showed that the CMOS detector improved delineation of smaller objects such as the stent struts (~70 μm) compared to the FPD. Further development and the potential for substantial clinical impact are suggested. PMID:26877577

  19. Accuracy and reliability of facial soft tissue depth measurements using cone beam computer tomography.

    PubMed

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

    2010-06-15

    It is important to have accurate and reliable measurements of soft tissue thickness for specific landmarks of the face and scalp when producing a facial reconstruction. In the past several methods have been created to measure facial soft tissue thickness (FSTT) in cadavers and in the living. The conventional spiral CT is mostly used to determine the FSTT but is associated with high radiation doses. The cone beam CT (CBCT) is a relatively new computer tomography system that focuses on head and neck regions and has much lower radiation doses. The aim of this study is to determine the accuracy and reliability of CBCT scans to measure the soft tissue thicknesses of the face. Seven cadaver heads were used. Eleven soft tissue landmarks were identified on each head and a punch hole was made on each landmark using a dermal biopsy punch. The seven cadaver heads were scanned in the CBCT with 0.3 and 0.4mm resolution. The FSTT at the 11 different sites (soft tissue landmarks) were measured using SimPlant-ortho volumetric software. These measurements were compared to the physical measurements. Statistical analysis for the reliability was done by means of the interclass coefficient (ICC) and the accuracy by means of the absolute error (AE) and absolute percentage error (APE). The intra-observer (0.976-0.999) and inter-observer (0.982-0.997) correlations of the CBCT and physical measurements were very high. There was no clinical significant difference between the measurements made on the CBCT images and the physical measurements. Increasing the voxel size from 0.4 to 0.3mm resulted in a slight increase of accuracy. Cone beam CT images of the face using routine scanning protocols are reliable for measuring soft tissue thickness in the facial region and give a good representation of the facial soft tissues. For more accurate data collection the 0.3mm voxel size should be considered.

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

    PubMed

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

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  2. Correlation between acoustic rhinometry, computed rhinomanometry and cone-beam computed tomography in mouth breathers with transverse maxillary deficiency.

    PubMed

    Sakai, Raquel Harumi Uejima Satto; Marson, Fernando Augusto Lima; Sakuma, Emerson Taro Inoue; Ribeiro, José Dirceu; Sakano, Eulália

    2016-11-25

    To provide clinical information and diagnosis in mouth breathers with transverse maxillary deficiency with posterior crossbite, numerous exams can be performed; however, the correlation among these exams remains unclear. To evaluate the correlation between acoustic rhinometry, computed rhinomanometry, and cone-beam computed tomography in mouth breathers with transverse maxillary deficiency. A cross-sectional study was conducted in 30 mouth breathers with transverse maxillary deficiency (7-13 y.o.) patients with posterior crossbite. The examinations assessed: (i) acoustic rhinometry: nasal volumes (0-5cm and 2-5cm) and minimum cross-sectional areas 1 and 2 of nasal cavity; (ii) computed rhinomanometry: flow and average inspiratory and expiratory resistance; (iii) cone-beam computed tomography: coronal section on the head of inferior turbinate (Widths 1 and 2), middle turbinate (Widths 3 and 4) and maxilla levels (Width 5). Acoustic rhinometry and computed rhinomanometry were evaluated before and after administration of vasoconstrictor. Results were compared by Spearman's correlation and Mann-Whitney tests (α=0.05). Positive correlations were observed between: (i) flow evaluated before administration of vasoconstrictor and Width 4 (Rho=0.380) and Width 5 (Rho=0.371); (ii) Width 2 and minimum cross-sectional areas 1 evaluated before administration of vasoconstrictor (Rho=0.380); (iii) flow evaluated before administration of vasoconstrictor and nasal volumes of 0-5cm (Rho=0.421), nasal volumes of 2-5cm (Rho=0.393) and minimum cross-sectional areas 1 (Rho=0.375); (iv) Width 4 and nasal volumes of 0-5cm evaluated before administration of vasoconstrictor (Rho=0.376), nasal volumes of 2-5cm evaluated before administration of vasoconstrictor (Rho=0.376), minimum cross-sectional areas 1 evaluated before administration of vasoconstrictor (Rho=0.410) and minimum cross-sectional areas 1 after administration of vasoconstrictor (Rho=0.426); (v) Width 5 and Width 1 (Rho=0

  3. Low dose megavoltage cone beam computed tomography with an unflattened 4 MV beam from a carbon target.

    PubMed

    Faddegon, Bruce A; Wu, Vincent; Pouliot, Jean; Gangadharan, Bijumon; Bani-Hashemi, Ali

    2008-12-01

    Megavoltage cone beam computed tomography (MVCBCT) is routinely used for visualizing anatomical structures and implanted fiducials for patient positioning in radiotherapy. MVCBCT using a 6 MV treatment beam with high atomic number (Z) target and flattening filter in the beamline, as done conventionally, has lower image quality than can be achieved with a MV beam due to heavy filtration of the low-energy bremsstrahlung. The unflattened beam of a low Z target has an abundance of diagnostic energy photons, detected with modern flat panel detectors with much higher efficiency given the same dose to the patient. This principle guided the development of a new megavoltage imaging beamline (IBL) for a commercial radiotherapy linear accelerator. A carbon target was placed in one of the electron primary scattering foil slots on the target-foil slide. A PROM on a function controller board was programed to put the carbon target in place for MVCBCT. A low accelerating potential of 4.2 MV was used for the IBL to restrict leakage of primary electrons through the target such that dose from x rays dominated the signal in the monitor chamber and the patient surface dose. Results from phantom and cadaver images demonstrated that the IBL had much improved image quality over the treatment beam. For similar imaging dose, the IBL improved the contrast-to-noise ratio by as much as a factor of 3 in soft tissue over that of the treatment beam. The IBL increased the spatial resolution by about a factor of 2, allowing the visualization of finer anatomical details. Images of the cadaver contained useful information with doses as low as 1 cGy. The IBL may be installed on certain models of linear accelerators without mechanical modification and results in significant improvement in the image quality with the same dose, or images of the same quality with less than one-third of the dose.

  4. Low dose megavoltage cone beam computed tomography with an unflattened 4 MV beam from a carbon target

    SciTech Connect

    Faddegon, Bruce A.; Wu, Vincent; Pouliot, Jean; Gangadharan, Bijumon; Bani-Hashemi, Ali

    2008-12-15

    Megavoltage cone beam computed tomography (MVCBCT) is routinely used for visualizing anatomical structures and implanted fiducials for patient positioning in radiotherapy. MVCBCT using a 6 MV treatment beam with high atomic number (Z) target and flattening filter in the beamline, as done conventionally, has lower image quality than can be achieved with a MV beam due to heavy filtration of the low-energy bremsstrahlung. The unflattened beam of a low Z target has an abundance of diagnostic energy photons, detected with modern flat panel detectors with much higher efficiency given the same dose to the patient. This principle guided the development of a new megavoltage imaging beamline (IBL) for a commercial radiotherapy linear accelerator. A carbon target was placed in one of the electron primary scattering foil slots on the target-foil slide. A PROM on a function controller board was programed to put the carbon target in place for MVCBCT. A low accelerating potential of 4.2 MV was used for the IBL to restrict leakage of primary electrons through the target such that dose from x rays dominated the signal in the monitor chamber and the patient surface dose. Results from phantom and cadaver images demonstrated that the IBL had much improved image quality over the treatment beam. For similar imaging dose, the IBL improved the contrast-to-noise ratio by as much as a factor of 3 in soft tissue over that of the treatment beam. The IBL increased the spatial resolution by about a factor of 2, allowing the visualization of finer anatomical details. Images of the cadaver contained useful information with doses as low as 1 cGy. The IBL may be installed on certain models of linear accelerators without mechanical modification and results in significant improvement in the image quality with the same dose, or images of the same quality with less than one-third of the dose.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Digital replacement of the distorted dentition acquired by cone beam computed tomography (CBCT): a pilot study.

    PubMed

    Nairn, N J; Ayoub, A F; Barbenel, J; Moos, K; Naudi, K; Ju, X; Khambay, B S

    2013-11-01

    During cone beam computed tomography (CBCT) scanning, intra-oral metallic objects may produce streak artefacts, which impair the occlusal surface of the teeth. This study aimed to determine the accuracy of replacement of the CBCT dentition with a more accurate dentition and to determine the clinical feasibility of the method. Impressions of the teeth of six cadaveric skulls with unrestored dentitions were taken and acrylic base plates constructed incorporating radiopaque registration markers. Each appliance was fitted to the skull and a CBCT performed. Impressions were taken of the dentition with the devices in situ and dental models were produced. These were CBCT-scanned and the images of the skulls and models imported into computer-aided design/computer-aided manufacturing (CAD/CAM) software and aligned on the registration markers. The occlusal surfaces of each dentition were then replaced with the occlusal image of the corresponding model. The absolute mean distance between the registration markers in the skulls and the dental models was 0.09±0.02mm, and for the dentition was 0.24±0.09mm. When the method was applied to patients, the distance between markers was 0.12±0.04mm for the maxilla and 0.16±0.02mm for the mandible. It is possible to replace the inaccurate dentition on a CBCT scan using this method and to create a composite skull which is clinically acceptable.

  7. SADMFR guidelines for the use of Cone-Beam Computed Tomography/ Digital Volume Tomography.

    PubMed

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

    2014-01-01

    Cone-Beam Computed Tomography (CBCT) has been introduced in 1998. This radiological imaging procedure has been provided for dentistry and is comparable to computed tomography (CT) in medicine. It is expected that CBCT will have the same success in dental diagnostic imaging as computed tomography had in medicine. Just as CT is responsible for a significant rise in radiation dose to the population from medical X-ray diagnostics, CBCT studies will be accompanied by a significant increase of the dose to our patients by dentistry. Because of the growing concern for an uncritical and consequently rapidly increasing use of CBCT the Swiss Society of Dentomaxillofacial Radiology convened a first consensus conference in 2011 to formulate indications for CBCT, which can be used as guidelines. In this meeting, oral and maxillofacial surgery, orthodontics and temporomandibular joint disorders and diseases were treated and the most important and most experienced users of DVT in these areas were asked to participate. In general, a highly restrictive use of CBCT is required. Justifying main criterion for CBCT application is that additional, therapy-relevant information is expected that should lead to a significant benefit in patient care. All users of CBCT should have completed a structured, high-level training, just like that offered by the Swiss Society of Dentomaxillofacial Radiology.

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

    SciTech Connect

    Huang, Tzung-Chi; Chou, Kuei-Ting; Yang, Shih-Neng; Chang, Chih-Kai; Liang, Ji-An; Zhang, Geoffrey

    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.

  9. Hybrid simulation of scatter intensity in industrial cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    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.

  10. Cone beam computed tomography in paediatric dentistry: overview of recent literature.

    PubMed

    Aps, J K M

    2013-06-01

    The use of cone beam computed tomography (CBCT) in paediatric dentistry has been mentioned in numerous publications and case reports. The indications for the use of CBCT in paediatric dentistry, however, have not yet been properly addressed. On the other hand, the three basic principles of radiation protection (justification, limitation and optimisation) should suffice. A review of the current literature was used to assess the indications and contra-indications for the use of CBCT in paediatric dentistry. Paramount is the fact that CBCT generates a higher effective dose to the tissues than traditional dental radiographic exposures do. The effective radiation dose should not be underestimated, especially not in children, who are much more susceptible to stochastic biological effects. The thyroid gland in particular should be kept out of the primary beam as much as possible. As with any other radiographical technique, routine use of CBCT is not acceptable clinical practice. CBCT certainly has a place in paediatric dentistry, but its use must be justified on a patient case individual basis.

  11. Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

    SciTech Connect

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C.

    2011-02-15

    Purpose: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. Methods: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. Results: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms

  12. Cone beam computed tomography of plastinated hearts for instruction of radiological anatomy.

    PubMed

    Chang, Chih-Wei; Atkinson, Gregory; Gandhi, Niket; Farrell, Michael L; Labrash, Steven; Smith, Alice B; Norton, Neil S; Matsui, Takashi; Lozanoff, Scott

    2016-09-01

    Radiological anatomy education is an important aspect of the medical curriculum. The purpose of this study was to establish and demonstrate the use of plastinated anatomical specimens, specifically human hearts, for use in radiological anatomy education. Four human hearts were processed with routine plastination procedures at room temperature. Specimens were subjected to cone beam computed tomography and a graphics program (ER3D) was applied to generate 3D cardiac models. A comparison was conducted between plastinated hearts and their corresponding computer models based on a list of morphological cardiac features commonly studied in the gross anatomy laboratory. Results showed significant correspondence between plastinations and CBCT-generated 3D models (98 %; p < .01) for external structures and 100 % for internal cardiac features, while 85 % correspondence was achieved between plastinations and 2D CBCT slices. Complete correspondence (100 %) was achieved between key observations on the plastinations and internal radiological findings typically required of medical student. All pathologic features seen on the plastinated hearts were also visualized internally with the CBCT-generated models and 2D slices. These results suggest that CBCT-derived slices and models can be successfully generated from plastinated material and provide accurate representations for radiological anatomy education.

  13. Imaging characteristics of distance-driven method in a prototype cone-beam computed tomography (CBCT)

    NASA Astrophysics Data System (ADS)

    Choi, Sunghoon; Kim, Ye-seul; Lee, Haenghwa; Lee, Donghoon; Seo, Chang-Woo; Kim, Hee-Joung

    2016-03-01

    Cone-beam computed tomography (CBCT) has widely been used and studied in both medical imaging and radiation therapy. The aim of this study was to evaluate our newly developed CBCT system by implementing a distance-driven system modeling technique in order to produce excellent and accurate cross-sectional images. For the purpose of comparing the performance of the distance-driven methods, we also performed pixel-driven and ray-driven techniques when conducting forward- and back-projection schemes. We conducted the Feldkamp-Davis-Kress (FDK) algorithm and simultaneous algebraic reconstruction technique (SART) to retrieve a volumetric information of scanned chest phantom. The results indicated that contrast-to-noise (CNR) of the reconstructed images by using FDK and SART showed 8.02 and 15.78 for distance-driven, whereas 4.02 and 5.16 for pixel-driven scheme and 7.81 and 13.01 for ray-driven scheme, respectively. This could demonstrate that distance-driven method described more closely the chest phantom compared to pixel- and ray-driven. However, both elapsed time for modeling a system matrix and reconstruction time took longer time when performing the distance-driven scheme. Therefore, future works will be directed toward reducing computational time to acceptable limits for real applications.

  14. Influence of anatomical location on CT numbers in cone beam computed tomography.

    PubMed

    Oliveira, Matheus L; Tosoni, Guilherme M; Lindsey, David H; Mendoza, Kristopher; Tetradis, Sotirios; Mallya, Sanjay M

    2013-04-01

    To assess the influence of anatomical location on computed tomography (CT) numbers in mid- and full field of view (FOV) cone beam computed tomography (CBCT) scans. Polypropylene tubes with varying concentrations of dipotassium hydrogen phosphate (K₂HPO₄) solutions (50-1200 mg/mL) were imaged within the incisor, premolar, and molar dental sockets of a human skull phantom. CBCT scans were acquired using the NewTom 3G and NewTom 5G units. The CT numbers of the K₂HPO₄ phantoms were measured, and the relationship between CT numbers and K₂HPO₄ concentration was examined. The measured CT numbers of the K₂HPO₄ phantoms were compared between anatomical sites. At all six anatomical locations, there was a strong linear relationship between CT numbers and K₂HPO₄ concentration (R(2)>0.93). However, the absolute CT numbers varied considerably with the anatomical location. The relationship between CT numbers and object density is not uniform through the dental arch on CBCT scans. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Cone-Beam Computed Tomography and Radiographs in Dentistry: Aspects Related to Radiation Dose

    PubMed Central

    Lorenzoni, Diego Coelho; Bolognese, Ana Maria; Garib, Daniela Gamba; Guedes, Fabio Ribeiro; Sant'Anna, Eduardo Franzotti

    2012-01-01

    Introduction. The aim of this study was to discuss the radiation doses associated with plain radiographs, cone-beam computed tomography (CBCT), and conventional computed tomography (CT) in dentistry, with a special focus on orthodontics. Methods. A systematic search for articles was realized by MEDLINE from 1997–March 2011. Results. Twenty-seven articles met the established criteria. The data of these papers were grouped in a table and discussed. Conclusions. Increases in kV, mA, exposure time, and field of view (FOV) increase the radiation dose. The dose for CT is greater than other modalities. When the full-mouth series (FMX) is performed with round collimation, the orthodontic radiographs transmit higher dose than most of the large FOV CBCT, but it can be reduced if used rectangular collimation, showing lower effective dose than large FOV CBCT. Despite the image quality, the CBCT does not replace the FMX. In addition to the radiation dose, image quality and diagnostic needs should be strongly taken into account. PMID:22548064

  16. Preliminary evaluation of cone beam computed tomography in three-dimensional cephalometry for clinical application

    PubMed Central

    Li, Na; Hu, Bo; Mi, Fanglin; Song, Jinlin

    2017-01-01

    The present study was conducted to evaluate the three-dimensional (3D) cephalometry accuracy of cone-beam computed tomography (CBCT). A total of 40 newly diagnosed orthodontic patients (including 18 males and 22 females; age range, 12–18 years) were subjected to CBCT scanning and X-ray imaging in order to obtain lateral cephalograms. The 3D CBCT cephalograms were reconstructed and measured with in vivo 5.1 software, and compared with the results from the conventional 2D lateral cephalograms. Measurements in the two images were performed twice using the Steiner and Tweed standards and a single analyzer paired t-test was used to analyze the differences between the two cephalometric methods. The results indicated that the two methods showed significant differences in all 12 angle and 5 linear measurements (P<0.05). These findings indicated that CBCT is a more accurate technique compared with the conventional 2D method. In conclusion, CBCT may provide diagnostic and treatment information for maxillofacial deformities by using fast computer-aided analysis platform. PMID:28565862

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

    NASA Astrophysics Data System (ADS)

    Wu, Jay; Shih, Cheng-Ting; Ho, Chang-hung; Liu, Yan-Lin; Chang, Yuan-Jen; Min Chao, Max; Hsu, Jui-Ting

    2014-11-01

    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.

  18. Geometric calibration using bundle adjustment for cone-beam computed tomography devices

    NASA Astrophysics Data System (ADS)

    Ladikos, Alexander; Wein, Wolfgang

    2012-03-01

    In this paper we present a novel geometric calibration procedure for cone-beam computed tomography (CBCT) devices with arbitrary geometry using a calibration phantom containing steel beads. In contrast to typical calibration procedures the position of the beads does not have to be known precisely as it is also recovered during calibration. In addition, the arrangement of the beads inside the phantom is very flexible and does not have to follow hard constraints. The bead centers are extracted with subpixel precision from the projection images while taking the absorption properties of the calibration phantom into account. Based on the recovered center positions and phantom geometry, the projection geometry is computed for every projection image. This geometry can be arbitrary and does not have to lie on a specific path, e.g. a circle. This allows to calibrate devices with reproducible mechanical errors in the gantry movement. We present an evaluation of the point extraction and the calibration procedure on ground-truth data and show reconstruction results on a device calibrated using the proposed calibration method.

  19. Reliability of frontal sinus by cone beam-computed tomography (CBCT) for individual identification.

    PubMed

    Cossellu, Gianguido; De Luca, Stefano; Biagi, Roberto; Farronato, Giampietro; Cingolani, Mariano; Ferrante, Luigi; Cameriere, Roberto

    2015-12-01

    Analysis of the frontal sinus is an important tool in personal identification. Cone beam-computed tomography (CBCT) is also progressively replacing conventional radiography and multi-slice computed tomography (MSCT) in human identification. The aim of this study is to develop a reproducible technique and measurements from 3D reconstructions obtained with CBCT, for use in human identification. CBCT from 150 patients (91 female, 59 male), aged between 15 and 78 years, was analysed with the specific software program MIMICS 11.11 (Materialise N.V., Leuven, Belgium). Corresponding 3D volumes were generated and maximal dimensions along 3 directions (x, y, z), X M, Y M, Z M (in mm), total volume area (in mm(3)), V t, and total surface (in mm(2)), S t, were calculated. Correlation analysis showed that sinus surfaces were strongly correlated with their volume (r = 0.976). Frontal sinuses were separate in 21 subjects (14 %), fused in 67 (44.6 %) and found on only one side (unilateral) in 9 (6 %). A Prominent Middle of Fused Sinus (PMS) was found in 53 subjects (35.3 %). The intra- (0.963-0.999) and inter-observer variability (0.973-0.999) showed a great agreement and a substantial homogeneity of evaluation.

  20. Image analysis and superimposition of 3-dimensional cone-beam computed tomography models

    PubMed Central

    Cevidanes, Lucia H. S.; Styner, Martin A.; Proffit, William R.

    2013-01-01

    Three-dimensional (3D) imaging techniques can provide valuable information to clinicians and researchers. But as we move from traditional 2-dimensional (2D) cephalometric analysis to new 3D techniques, it is often necessary to compare 2D with 3D data. Cone-beam computed tomography (CBCT) provides simulation tools that can help bridge the gap between image types. CBCT acquisitions can be made to simulate panoramic, lateral, and posteroanterior cephalometric radioagraphs so that they can be compared with preexisting cephalometric databases. Applications of 3D imaging in orthodontics include initial diagnosis and superimpositions for assessing growth, treatment changes, and stability. Three-dimensional CBCT images show dental root inclination and torque, impacted and supernumerary tooth positions, thickness and morphology of bone at sites of mini-implants for anchorage, and osteotomy sites in surgical planning. Findings such as resorption, hyperplasic growth, displacement, shape anomalies of mandibular condyles, and morphological differences between the right and left sides emphasize the diagnostic value of computed tomography acquisitions. Furthermore, relationships of soft tissues and the airway can be assessed in 3 dimensions. PMID:16679201

  1. Precision of cephalometric landmark identification: Cone-beam computed tomography vs conventional cephalometric views

    PubMed Central

    Ludlow, John B.; Gubler, Maritzabel; Cevidanes, Lucia; Mol, André

    2009-01-01

    Introduction In this study, we compared the precision of landmark identification using displays of multi-planar cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). Methods Twenty presurgical orthodontic patients were radiographed with conventional Ceph and CBCT techniques. Five observers plotted 24 landmarks using computer displays of multi-planer reconstruction (MPR) CBCT and Ceph views during separate sessions. Absolute differences between each observer’s plot and the mean of all observers were averaged as 1 measure of variability (ODM). The absolute difference of each observer from any other observer was averaged as a second measure of variability (DEO). ANOVA and paired t tests were used to analyze variability differences. Results Radiographic modality and landmark were significant at P <0.0001 for DEO and ODM calculations. DEO calculations of observer variability were consistently greater than ODM. The overall correlation of 1920 paired ODM and DEO measurements was excellent at 0.972. All bilateral landmarks had increased precision when identified in the MPR views. Mediolateral variability was statistically greater than anteroposterior or caudal-cranial variability for 5 landmarks in the MPR views. Conclusions The MPR displays of CBCT volume images provide generally more precise identification of traditional cephalometric landmarks. More precise location of condylion, gonion, and orbitale overcomes the problem of superimposition of these bilateral landmarks seen in Ceph. Greater variability of certain landmarks in the mediolateral direction is probably related to inadequate definition of the landmarks in the third dimension. PMID:19732656

  2. Accuracy of 3D reconstructions based on cone beam computed tomography.

    PubMed

    Maret, D; Molinier, F; Braga, J; Peters, O A; Telmon, N; Treil, J; Inglèse, J M; Cossié, A; Kahn, J L; Sixou, M

    2010-12-01

    Three-dimensional imaging of teeth will increase its impact in clinical practice if reconstructions are metrically accurate. We hypothesized that, with cone beam computed tomography (CBCT) data, three-dimensional images of teeth can be reconstructed with the same accuracy and precision as with in vitro micro-computed tomography (micro-CT) data acquisition, the current reference standard. We used a sample of CBCT and micro-CT data taken of tooth germs. Volumes obtained with CBCT and micro-CT devices were statistically similar (n = 120, Passing-Bablok regression). Geometric deviations between CBCT and micro-CT three-dimensional surface reconstructions did not show any areas of important and systematic errors. Future investigations with the use of larger samples may also demonstrate that CBCT data will be helpful for a more in-depth study of other aspects of dental morphology--for example, assessing tooth development. With sufficient accuracy for clinical situations, potential future medical applications of such measurements with CBCT are envisaged.

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

    PubMed Central

    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 with Pearson chi-squared test. Results: Enamel pearls were detected in 36 subjects (4.69%). Of these enamel pearls, 19 were detected in male and 17 were in male. There was no statistically a significant association between prevalence of enamel pearls and sex. All of enamel pearls were detected in molar teeth, for prevalence 0.83%. Conclusion: All of enamel pearls are found upper and lower molar teeth, especially the most commonly in maxillary second and third molars. Key words: Enamel pearls, ectopic mineralization, radiography, CBCT, DVT. PMID:22143707

  4. Human identification through frontal sinus 3D superimposition: Pilot study with Cone Beam Computer Tomography.

    PubMed

    Beaini, Thiago Leite; Duailibi-Neto, Eduardo F; Chilvarquer, Israel; Melani, Rodolfo F H

    2015-11-01

    As a unique anatomical feature of the human body, the frontal sinus morphology has been used for identification of unknown bodies with many techniques, mostly using 2D postero-anterior X-rays. With the increase of the use of Cone-Beam Computer Tomography (CBCT), the availability of this exam as ante-mortem records should be considered. The purpose of this study is to establish a new technique for frontal sinus identification through direct superimposition of 3D volumetric models obtained from CBCT exam, by testing two distinct situations. First, a reproducibility test, where two observers independently rendered models of frontal sinus from a sample 20 CBCT exams and identified them on each other's list. In the second situation, one observer tested the protocol and established on different exams of three individual. Using the open source DICOM viewer InVesallius(®) for rendering, Mesh Lab(®,) for positioning the models and CloudCompare for volumetric comparison, both observers matched cases with 100% accuracy and the level of coincidence in a identification situation. The uniqueness of the frontal sinus topography is remarkable and through the described technique, can be used in forensic as an identification method whenever both the sinus structure and antemortem computer tomography is available. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  5. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    PubMed

    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

  6. Respiratory motion guided four dimensional cone beam computed tomography: encompassing irregular breathing

    NASA Astrophysics Data System (ADS)

    O'Brien, Ricky T.; Cooper, Benjamin J.; Kipritidis, John; Shieh, Chun-Chien; Keall, Paul J.

    2014-02-01

    Four dimensional cone beam computed tomography (4DCBCT) images suffer from angular under sampling and bunching of projections due to a lack of feedback between the respiratory signal and the acquisition system. To address this problem, respiratory motion guided 4DCBCT (RMG-4DCBCT) regulates the gantry velocity and projection time interval, in response to the patient’s respiratory signal, with the aim of acquiring evenly spaced projections in a number of phase or displacement bins during the respiratory cycle. Our previous study of RMG-4DCBCT was limited to sinusoidal breathing traces. Here we expand on that work to provide a practical algorithm for the case of real patient breathing data. We give a complete description of RMG-4DCBCT including full details on how to implement the algorithms to determine when to move the gantry and when to acquire projections in response to the patient’s respiratory signal. We simulate a realistic working RMG-4DCBCT system using 112 breathing traces from 24 lung cancer patients. Acquisition used phase-based binning and parameter settings typically used on commercial 4DCBCT systems (4 min acquisition time, 1200 projections across 10 respiratory bins), with the acceleration and velocity constraints of current generation linear accelerators. We quantified streaking artefacts and image noise for conventional and RMG-4DCBCT methods by reconstructing projection data selected from an oversampled set of Catphan phantom projections. RMG-4DCBCT allows us to optimally trade-off image quality, acquisition time and image dose. For example, for the same image quality and acquisition time as conventional 4DCBCT approximately half the imaging dose is needed. Alternatively, for the same imaging dose, the image quality as measured by the signal to noise ratio, is improved by 63% on average. C-arm cone beam computed tomography systems, with an acceleration up to 200°/s2, a velocity up to 100°/s and the acquisition of 80 projections per second

  7. On the computational implementation of forward and back-projection operations for cone-beam computed tomography.

    PubMed

    Karimi, Davood; Ward, Rabab

    2016-08-01

    Forward- and back-projection operations are the main computational burden in iterative image reconstruction in computed tomography. In addition, their implementation has to be accurate to ensure stable convergence to a high-quality image. This paper reviews and compares some of the variations in the implementation of these operations in cone-beam computed tomography. We compare four algorithms for computing the system matrix, including a distance-driven algorithm, an algorithm based on cubic basis functions, another based on spherically symmetric basis functions, and a voxel-driven algorithm. The focus of our study is on understanding how the choice of the implementation of the system matrix will influence the performance of iterative image reconstruction algorithms, including such factors as the noise strength and spatial resolution in the reconstructed image. Our experiments with simulated and real cone-beam data reveal the significance of the speed-accuracy trade-off in the implementation of the system matrix. Our results suggest that fast convergence of iterative image reconstruction methods requires accurate implementation of forward- and back-projection operations, involving a direct estimation of the convolution of the footprint of the voxel basis function with the surface of the detectors. The required accuracy decreases by increasing the resolution of the projection measurements beyond the resolution of the reconstructed image. Moreover, reconstruction of low-contrast objects needs more accurate implementation of these operations. Our results also show that, compared with regularized reconstruction methods, the behavior of iterative reconstruction algorithms that do not use a proper regularization is influenced more significantly by the implementation of the forward- and back-projection operations.

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

    PubMed Central

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

    2016-01-01

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

  9. Imaging doses in radiation therapy from kilovoltage cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Hyer, Daniel Ellis

    Advances in radiation treatment delivery, such as intensity modulated radiation therapy (IMRT), have made it possible to deliver large doses of radiation with a high degree of conformity. While highly conformal treatments offers the advantage of sparing surrounding normal tissue, this benefit can only be realized if the patient is accurately positioned during each treatment fraction. The need to accurately position the patient has led to the development and use of gantry mounted kilovoltage cone-beam computed tomography (kV-CBCT) systems. These systems are used to acquire high resolution volumetric images of the patient which are then digitally registered with the planning CT dataset to confirm alignment of the patient on the treatment table. While kV-CBCT is a very useful tool for aligning the patient prior to treatment, daily use in a high fraction therapy regimen results in a substantial radiation dose. In order to quantify the radiation dose associated with CBCT imaging, an anthropomorphic phantom representing a 50th percentile adult male and a fiber-optic coupled (FOC) dosimetry system were both constructed as part of this dissertation. These tools were then used to directly measure organ doses incurred during clinical protocols for the head, chest, and pelvis. For completeness, the dose delivered from both the X-ray Volumetric Imager (XVI, Elekta Oncology Systems, Crawley, UK) and the On-Board Imager (OBI, Varian Medical Systems, Palo Alto, CA) were investigated. While this study provided a direct measure of organ doses for estimating risk to the patient, a practical method for estimating organ doses that could be performed with phantoms and dosimeters currently available at most clinics was also desired. To accomplish this goal, a 100 mm pencil ion chamber was used to measure the "cone beam dose index" (CBDI) inside standard CT dose index (CTDI) acrylic phantoms. A weighted CBDI (CBDIw), similar to the weighted CT dose index (CTDIw), was then calculated to

  10. Evaluation of the validity of the Bolton Index using cone-beam computed tomography (CBCT)

    PubMed Central

    Llamas, José M.; Cibrián, Rosa; Gandía, José L.; Paredes, Vanessa

    2012-01-01

    Aims: To evaluate the reliability and reproducibility of calculating the Bolton Index using cone-beam computed tomography (CBCT), and to compare this with measurements obtained using the 2D Digital Method. Material and Methods: Traditional study models were obtained from 50 patients, which were then digitized in order to be able to measure them using the Digital Method. Likewise, CBCTs of those same patients were undertaken using the Dental Picasso Master 3D® and the images obtained were then analysed using the InVivoDental programme. Results: By determining the regression lines for both measurement methods, as well as the difference between both of their values, the two methods are shown to be comparable, despite the fact that the measurements analysed presented statistically significant differences. Conclusions: The three-dimensional models obtained from the CBCT are as accurate and reproducible as the digital models obtained from the plaster study casts for calculating the Bolton Index. The differences existing between both methods were clinically acceptable. Key words:Tooth-size, digital models, bolton index, CBCT. PMID:22549690

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

    PubMed Central

    Geha, Hassem; Sankar, Vidya; Teixeira, Fabricio B.; McMahan, Clyde Alex; Noujeim, Marcel

    2015-01-01

    Purpose 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. Materials and Methods 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. Results 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. Conclusion 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. PMID:26389057

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

    PubMed

    Chennoju, Sai Kiran; Pachigolla, Ramaswamy; Govada, Vanya Mahitha; Alapati, Satish; Balla, Smitha

    2016-05-01

    Bone dysplasias comprise of a condition where the normal bone is replaced with fibrous tissue. Periapical Cemento-Osseous Dysplasia (PCOD) is a benign fibro-osseous condition where bone tissue is supplanted with fibrous tissue and cementum-like material. This condition affects mostly mandibular anterior region and rarely occurs in the maxilla. PCOD is seen above 30 years of age and has slight female predilection. Generally the teeth related to such lesions appear to be vital and are usually asymptomatic. These lesions are mostly seen during routine radiographic examination whose presentation may vary from complete radiolucency to dense radiopacity. The advent of Cone Beam Computed Tomography (CBCT) has brought a massive change in the field of dentistry which has become an important tool for diagnosis. Hence we hereby present an unusual case of cemento-osseous dysplasia in an unfamiliar location with an atypical presentation. The shape of the pathology was completely idiosyncratic and different from an orthodox lesion of COD, as the lesion was observed to grow out of the palatal surface with a prominent palatal expansion. This case highlights the importance of CBCT in radiographic diagnosis and in evaluating the characteristics of such lesion, which present with high diagnostic dilemma.

  13. Analysis of Interfraction Prostate Motion Using Megavoltage Cone Beam Computed Tomography

    SciTech Connect

    Bylund, Kevin C. Bayouth, John E.; Smith, Mark C.; Hass, A. Curtis; Bhatia, Sudershan K.; Buatti, John M..

    2008-11-01

    Purpose: Determine the degree of interfraction prostate motion and its components measured by using daily megavoltage (MV) cone beam computed tomography (CBCT) imaging. Methods and Materials: A total of 984 daily MV CBCT images from 24 patients undergoing definitive intensity-modulated radiotherapy for localized prostate cancer were analyzed retrospectively. Pretreatment couch shifts, based on physician registration of MV CBCT to planning CT data sets, were used as a measure of daily interfraction motion. Off-line bony registration was performed to separate bony misalignment from internal organ motion. Interobserver and intraobserver variation studies were performed on 20 MV CBCT images. Results: Mean interfraction prostate motion was 6.7 mm, with the greatest single-axis deviation in the anterior-posterior (AP) direction. The largest positional inaccuracy was accounted for by systematic deviations in bony misalignment, whereas random deviations occurred from bony misalignment and internal prostate motion. In the aggregate, AP motion did not correlate with days elapsed since beginning therapy or on average with rectal size at treatment planning. Interobserver variation was greatest in the AP direction, decreased in experienced observers, and further decreased in intraobserver studies. Mean interfraction motion during the first 6 days of therapy, when used as a subsequent offset, reduced acceptable AP planning target volume margins by 50%. Conclusion: The MV CBCT is a practical direct method of daily localization that shows significant interfraction motion with respect to conventional three-dimensional conformal and intensity-modulated radiotherapy margins, similar to that measured in other modalities.

  14. Configuration of the inferior alveolar canal as detected by cone beam computed tomography

    PubMed Central

    Nair, Umadevi P; Yazdi, Mehran H; Nayar, Gautam M; Parry, Heath; Katkar, Rujuta A; Nair, Madhu K

    2013-01-01

    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. PMID:24347885

  15. Bilateral and pseudobilateral tonsilloliths: Three dimensional imaging with cone-beam computed tomography

    PubMed Central

    Mısırlıoglu, Melda; Nalcaci, Rana; Yardımcı, Selmi

    2013-01-01

    Purpose 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. Materials and Methods 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 mm3 of the segmented three dimensional models were obtained. Results 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 302.5mm3. The patients with bilaterally multiple and large calcifications were found to be symptomatic. Conclusion 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. PMID:24083209

  16. Comparative adoption of cone beam computed tomography and panoramic radiography machines across Australia.

    PubMed

    Zhang, A; Critchley, S; Monsour, P A

    2016-12-01

    The aim of the present study was to assess the current adoption of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines across Australia. Information regarding registered CBCT and PR machines was obtained from radiation regulators across Australia. The number of X-ray machines was correlated with the population size, the number of dentists, and the gross state product (GSP) per capita, to determine the best fitting regression model(s). In 2014, there were 232 CBCT and 1681 PR machines registered in Australia. Based on absolute counts, Queensland had the largest number of CBCT and PR machines whereas the Northern Territory had the smallest number. However, when based on accessibility in terms of the population size and the number of dentists, the Australian Capital Territory had the most CBCT machines and Western Australia had the most PR machines. The number of X-ray machines correlated strongly with both the population size and the number of dentists, but not with the GSP per capita. In 2014, the ratio of PR to CBCT machines was approximately 7:1. Projected increases in either the population size or the number of dentists could positively impact on the adoption of PR and CBCT machines in Australia. © 2016 Australian Dental Association.

  17. Three-dimensional analysis of deciduous maxillary anterior teeth using cone-beam computed tomography.

    PubMed

    Jung, M-S; Lee, S-P; Kim, G-T; Choi, S-C; Park, J-H; Kim, J-W

    2012-03-01

    The recent introduction of cone-beam computed tomography (CBCT) into the medical field has allowed the nondestructive investigation of internal structures at relatively low cost and radiation exposure. The accuracy of CBCT in both two and three dimensions has been demonstrated, and CBCT has been used successfully for craniofacial anatomy. Knowing the anatomical structure of deciduous teeth is essential for clinical dentistry. However, the root structure of deciduous teeth is rarely reported because of the scarcity of intact deciduous teeth without root resorption. The aim of this study was to evaluate the intact root form of deciduous teeth using CBCT. Data from 38 young children was analyzed using an image-analyzing program. The degree of buccal dilacerations was 26.3° for deciduous maxillary central incisors (DMA), 16.5° for deciduous maxillary lateral incisors (DMB), and 17.5° for deciduous maxillary canines (DMC) in about half of the root length. The crown-to-root ratios were 0.52 for DMA, 0.48 for DMB, and 0.52 for DMC. These data will be helpful for understanding the development of dentition, and for clinical dentistry.

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

    PubMed

    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.

  19. Assessment of maxillary third molars with panoramic radiography and cone-beam computed tomography

    PubMed Central

    Jung, Yun-Hoa

    2015-01-01

    Purpose This study investigated maxillary third molars and their relation to the maxillary sinus using panoramic radiography and cone-beam computed tomography (CBCT). Materials and Methods A total of 395 maxillary third molars in 234 patients were examined using panoramic radiographs and CBCT images. We examined the eruption level of the maxillary third molars, the available retromolar space, the angulation, the relationship to the second molars, the number of roots, and the relationship between the roots and the sinus. Results Females had a higher frequency of maxillary third molars with occlusal planes apical to the cervical line of the second molar (Level C) than males. All third molars with insufficient retromolar space were Level C. The most common angulation was vertical, followed by buccoangular. Almost all of the Level C molars were in contact with the roots of the second molar. Erupted teeth most commonly had three roots, and completely impacted teeth most commonly had one root. The superimposition of one third of the root and the sinus floor was most commonly associated with the sinus floor being located on the buccal side of the root. Conclusion Eruption levels were differently distributed according to gender. A statistically significant association was found between the eruption level and the available retromolar space. When panoramic radiographs showed a superimposition of the roots and the sinus floor, expansion of the sinus to the buccal side of the root was generally observed in CBCT images. PMID:26730371

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

    NASA Astrophysics Data System (ADS)

    Paul, Jijo; Vogl, Thomas J.; Chacko, Annamma

    2015-10-01

    To evaluate hepatic tumor detection using ultrafast cone-beam computed tomography (UCBCT) cross-sectional and 3D post-processed image datasets. 657 patients were examined using UCBCT during hepatic transarterial chemoembolization (TACE), and data were collected retrospectively from January 2012 to September 2014. Tumor detectability, diagnostic ability, detection accuracy and sensitivity were examined for different hepatic tumors using UCBCT cross-sectional, perfusion blood volume (PBV) and UCBCT-MRI (magnetic resonance imaging) fused image datasets. Appropriate statistical tests were used to compare collected sample data. Fused image data showed the significantly higher (all P  <  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.

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

    PubMed Central

    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

  2. Breast density measurement: 3D cone beam computed tomography (CBCT) images versus 2D digital mammograms

    NASA Astrophysics Data System (ADS)

    Han, Tao; Lai, Chao-Jen; Chen, Lingyun; Liu, Xinming; Shen, Youtao; Zhong, Yuncheng; Ge, Shuaiping; Yi, Ying; Wang, Tianpeng; Yang, Wei T.; Shaw, Chris C.

    2009-02-01

    Breast density has been recognized as one of the major risk factors for breast cancer. However, breast density is currently estimated using mammograms which are intrinsically 2D in nature and cannot accurately represent the real breast anatomy. In this study, a novel technique for measuring breast density based on the segmentation of 3D cone beam CT (CBCT) images was developed and the results were compared to those obtained from 2D digital mammograms. 16 mastectomy breast specimens were imaged with a bench top flat-panel based CBCT system. The reconstructed 3D CT images were corrected for the cupping artifacts and then filtered to reduce the noise level, followed by using threshold-based segmentation to separate the dense tissue from the adipose tissue. For each breast specimen, volumes of the dense tissue structures and the entire breast were computed and used to calculate the volumetric breast density. BI-RADS categories were derived from the measured breast densities and compared with those estimated from conventional digital mammograms. The results show that in 10 of 16 cases the BI-RADS categories derived from the CBCT images were lower than those derived from the mammograms by one category. Thus, breasts considered as dense in mammographic examinations may not be considered as dense with the CBCT images. This result indicates that the relation between breast cancer risk and true (volumetric) breast density needs to be further investigated.

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

    PubMed Central

    Jung, Yun-Hoa

    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 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. Results 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. Conclusion 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. PMID:23301207

  4. Integration of Digital Dental Casts in Cone-Beam Computed Tomography Scans

    PubMed Central

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

    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 surgery, titanium markers were glued to the gingiva. Next, a CBCT scan and dental impressions were made. During the impression-taking procedure, the titanium markers were transferred to the impression. The impressions were scanned, and all CBCT datasets were exported in DICOM format. The two datasets were matched, and the dentition derived from the scanned impressions was transferred to the CBCT of the patient. After matching the two datasets, the average distance between the corresponding markers was 0.1 mm. This novel method allows for the integration of digital dental casts into CBCT scans, overcoming problems such as unwanted extra radiation exposure, distortion of soft tissues due to the use of bite jigs, and time-consuming digital data handling. PMID:23050159

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

    PubMed Central

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

    2015-01-01

    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

  6. Quantitative Assessment of Cervical Vertebral Maturation Using Cone Beam Computed Tomography in Korean Girls

    PubMed Central

    Byun, Bo-Ram; Kim, Yong-Il; Maki, Koutaro; Son, Woo-Sung

    2015-01-01

    This study was aimed to examine the correlation between skeletal maturation status and parameters from the odontoid process/body of the second vertebra and the bodies of third and fourth cervical vertebrae and simultaneously build multiple regression models to be able to estimate skeletal maturation status in Korean girls. Hand-wrist radiographs and cone beam computed tomography (CBCT) images were obtained from 74 Korean girls (6–18 years of age). CBCT-generated cervical vertebral maturation (CVM) was used to demarcate the odontoid process and the body of the second cervical vertebra, based on the dentocentral synchondrosis. Correlation coefficient analysis and multiple linear regression analysis were used for each parameter of the cervical vertebrae (P < 0.05). Forty-seven of 64 parameters from CBCT-generated CVM (independent variables) exhibited statistically significant correlations (P < 0.05). The multiple regression model with the greatest R2 had six parameters (PH2/W2, UW2/W2, (OH+AH2)/LW2, UW3/LW3, D3, and H4/W4) as independent variables with a variance inflation factor (VIF) of <2. CBCT-generated CVM was able to include parameters from the second cervical vertebral body and odontoid process, respectively, for the multiple regression models. This suggests that quantitative analysis might be used to estimate skeletal maturation status. PMID:25878721

  7. Detection of Procedural Errors during Root Canal Instrumentation using Cone Beam Computed Tomography

    PubMed Central

    Guedes, Orlando Aguirre; da Costa, Marcus Vinícius Corrêa; Dorilêo, Maura Cristiane Gonçales Orçati; de Oliveira, Helder Fernandes; Pedro, Fábio Luis Miranda; Bandeca, Matheus Coelho; Borges, Álvaro Henrique

    2015-01-01

    Background: This study investigated procedural errors made during root canal preparation with nickel-titanium (NiTi) instruments, using cone beam computed tomography (CBCT) imaging method. Materials and Methods: A total of 100 human mandibular molars were divided into five groups (n = 20) according to the NiTi system used for root canal preparation: Group 1 - BioRaCe, Group 2 - K3, Group 3 - ProTaper, Group 4 - Mtwo and Group 5 - Hero Shaper. CBCT images were obtained to detect procedural errors made during root canal preparation. Two examiners evaluated the presence or absence of fractured instruments, perforations, and canal transportations. Chi-square test was used for statistical analyzes. The significance level was set at a=5%. Results: In a total of 300 prepared root canals, 43 (14.33%) procedural errors were detected. Perforation was the procedural errors most commonly observed (58.14%). Most of the procedural errors were observed in the mesiobuccal root canal (48.84%). In the analysis of procedural errors, there was a significant difference (P < 0.05) between the groups of NiTi instruments. The root canals instrumented with BioRaCe had significantly less procedural errors. Conclusions: CBCT permitted the detection of procedural errors during root canal preparation. The frequency of procedural errors was low when root canals preparation was accomplished with BioRaCe system. PMID:25878475

  8. Digital panoramic radiography versus cone beam computed tomography in the delineation of maxillomandibular tumors.

    PubMed

    Almeida-Barros, Renata Quirino de; Abilio, Vanessa Maria Freire; Yamamoto, Angela Toshie Araki; Melo, Daniela Pita de; Godoy, Gustavo Pina; Bento, Patricia Meira

    2015-01-01

    This research aimed to compare the efficacy of digital panoramic radiography (DPR) with that of cone beam computed tomography (CBCT) for delineation of odontogenic and nonodontogenic tumors. From November 2009 through March 2011, 23 tumors in the maxillomandibular complex were diagnosed by histopathological examination. All DPRs and CBCTs were obtained and analyzed by a single previously calibrated radiologist, who considered the following radiographic aspects: clarity of the lesion edges, relation with dental elements, involvement of adjacent anatomical structures, cortical bone expansion and disruption, and, if present, type of involved anatomical structures and site of bone expansion and disruption. Of 23 patients, 15 (65.2%) were male and 8 (34.8%) were female. The tumor was classified as odontogenic in 73.9% of patients and nonodontogenic in 26.1% of patients. Analysis revealed that 56.5% of the tumors were located in the mandible, 34.8% in the maxilla, and 8.7% in both arches. For all analyzed variables, CBCTs offered more accurate details than did DPRs. Panoramic radiography should not be the examination of choice to visualize lesions in the maxillomandibular complex.

  9. Prevalence and Morphologic Characteristics of Ponticulus Posticus: Analysis Using Cone-Beam Computed Tomography

    PubMed Central

    Sekerci, Ahmet Ercan; Soylu, Emrah; Arikan, Mehtap Payveren; Ozcan, Gozde; Amuk, Mehmet; Kocoglu, Fatma

    2015-01-01

    Objective This study evaluated the prevalence and morphologic characteristics of ponticulus posticus (PP) by using cervical 3-dimensional (3-D) cone-beam computed tomography (CBCT) scan images. Methods This was a retrospective study conducted by selecting cervical 3-D CBCT images of 698 patients, which were examined for the presence and types of PP. Results In 257 patients, 438 PPs, complete or partial, bilateral or unilateral, were identified on the 698 cervical 3-D CBCT scans; therefore, the prevalence was 36.8%. Bilateral complete PP and partial PP were observed in 6.3% and 16.2% of subjects, respectively. There was a significant difference in the prevalence between males and females (P = .001) and between the right and left sides between males and females, but not between age groups. Conclusion Ponticulus posticus is a relatively common anomaly in this Turkish sample, which may have implications for those who perform clinical procedures on the upper cervical spine. PMID:26778928

  10. Normal Variations of Sphenoid Sinus and the Adjacent Structures Detected in Cone Beam Computed Tomography

    PubMed Central

    Rahmati, Azadeh; Ghafari, Roshanak; AnjomShoa, Maryam

    2016-01-01

    Statement of the Problem The sphenoid sinus is a common target of paranasal surgery. Functional endoscopic sinus surgery is likely to endanger the anatomic variations of vital structures adjacent to the sphenoid sinus. Purpose The aim of this study was to determine the variations of sphenoid sinus and the related structures by using cone-beam computed tomography (CBCT). Materials and Method In this descriptive-analytic study, CBCT images of 103 patients aged above 20-years were selected (206 sides). Degree of pneumatization of sphenoid sinus, pneumatization of the anterior clinoid process, pterygoid process, protrusion of optic canal, vidian canal, and foramen rotundum, as well as prevalence of sinus septa were recorded. Examinations were performed using On-Demand software (Version 1); data were analyzed by using chi-square test. Results There was a statistically significant correlation between the pterygoid pneumatization and vidian canal protrusion (p< 0.001), and foramen rotundum protrusion (p< 0.001). The optic canal protrusion was found to be significantly associated with the anterior clinoid pneumatization and pterygoid process (p< 0.001). Statistically significant relationship was also observed between the carotid canal protrusion and pterygoid process pneumatization (p< 0.001). Conclusion The anatomical variations of the sphenoid sinus tend to give rise to a complexity of symptoms and potentially serious complications. This variability necessitates a comprehensive understanding of the regional sphenoid sinus anatomy by a detailed CBCT sinus examination. PMID:26966706

  11. Pediatric Phantom Dosimetry of Kodak 9000 Cone-beam Computed Tomography.

    PubMed

    Yepes, Juan F; Booe, Megan R; Sanders, Brian J; Jones, James E; Ehrlich, Ygal; Ludlow, John B; Johnson, Brandon

    2017-05-15

    The purpose of the study was to evaluate the radiation dose of the Kodak 9000 cone-beam computed tomography (CBCT) device for different anatomical areas using a pediatric phantom. Absorbed doses resulting from maxillary and mandibular region three by five cm CBCT volumes of an anthropomorphic 10-year-old child phantom were acquired using optical stimulated dosimetry. Equivalent doses were calculated for radiosensitive tissues in the head and neck area, and effective dose for maxillary and mandibular examinations were calculated following the 2007 recommendations of the International Commission on Radiological Protection (ICRP). Of the mandibular scans, the salivary glands had the highest equivalent dose (1,598 microsieverts [μSv]), followed by oral mucosa (1,263 μSv), extrathoracic airway (pharynx, larynx, and trachea; 859 μSv), and thyroid gland (578 μSv). For the maxilla, the salivary glands had the highest equivalent dose (1,847 μSv), followed closely by oral mucosa (1,673 μSv), followed by the extrathoracic airway (pharynx, larynx, and trachea; 1,011 μSv) and lens of the eye (202 μSv). Compared to previous research of the Kodak 9000, completed with the adult phantom, a child receives one to three times more radiation for mandibular scans and two to 10 times more radiation for maxillary scans.

  12. Scatter correction for cone-beam computed tomography using moving blocker strips

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Mao, Weihua; Solberg, Timothy

    2011-03-01

    One well-recognized challenge of cone-beam computed tomography (CBCT) is the presence of scatter contamination within the projection images. Scatter degrades the CBCT image quality by decreasing the contrast, introducing shading artifacts and leading to inaccuracies in the reconstructed CT number. We propose a blocker-based approach to simultaneously estimate scatter signal and reconstruct the complete volume within the field of view (FOV) from a single CBCT scan. A physical strip attenuator (i.e., "blocker"), consists of lead strips, is inserted between the x-ray source and the patient. The blocker moves back and forth along z-axis during the gantry rotation. The two-dimensional (2D) scatter fluence is estimated by interpolating the signal from the blocked regions. A modified Feldkamp-Davis-Kress (FDK) algorithm and an iterative reconstruction based on the constraint optimization are used to reconstruct CBCT images from un-blocked projection data after the scatter signal is subtracted. An experimental study is performed to evaluate the performance of the proposed scatter correction scheme. The scatter-induced shading/cupping artifacts are substantially reduced in CBCT using the proposed strategy. In the experimental study using a CatPhan©600 phantom, CT number errors in the selected regions of interest are reduced from 256 to less than 20. The proposed method allows us to simultaneously estimate the scatter signal in projection data, reduce the imaging dose and obtain complete volumetric information within the FOV.

  13. Temporomandibular joint osteoarthritis: cone beam computed tomography findings, clinical features, and correlations.

    PubMed

    Cömert Kiliç, S; Kiliç, N; Sümbüllü, M A

    2015-10-01

    The aim of this study was to determine the prevalence of and associations between clinical signs and symptoms and cone beam computed tomography (CBCT) findings of temporomandibular joint osteoarthritis (TMJ-OA). Seventy-six patients (total 117 TMJ) with osteoarthritis were included in this study. Clinical signs and symptoms and CBCT findings were reviewed retrospectively. A considerable decrease in mandibular motions and mastication efficiency, and considerable increase in joint sounds and general pain complaints were observed. The most frequent condylar bony changes were erosion (110 joints, 94.0%), followed by flattening (108 joints, 92.3%), osteophytes (93 joints, 79.5%), hypoplasia (22 joints, 18.8%), sclerosis (14 joints, 12.0%), and subchondral cyst (four joints, 3.4%). Flattening of the articular eminence and pneumatization were each observed in five joints. Forty-one patients had bilateral degeneration and 35 had unilateral degeneration. Hypermobility was detected in 47 degenerative joints. Masticatory efficiency was negatively correlated with both condylar flattening and sclerosis, and general pain complaints was positively correlated with condylar flattening. Condylar erosion, flattening, osteophytes, pain, joint sounds, reduced jaw movements, and worsened mastication were common findings in TMJ-OA in the present study. Poor correlations were found between osseous changes and clinical signs and symptoms of TMJ-OA. CBCT is a powerful diagnostic tool for the diagnosis of TMJ-OA. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  14. Diagnosis of jaw and dentoalveolar fractures in a traumatized patient with cone beam computed tomography.

    PubMed

    Dölekoğlu, Semanur; Fişekçioğlu, Erdoğan; Ilgüy, Dilhan; Ilgüy, Mehmet; Bayirli, Gündüz

    2010-04-01

    The purpose of this case report is to discuss and illustrate the clinical usage of Cone Beam Computed Tomography (CBCT) for the diagnosis of maxillofacial fractures in a traumatized patient. In this presentation, a 30-year-old male patient who was referred to Oral Diagnosis and Radiology Department with a limitation of mouth opening was reported. The history of the patient revealed a traumatic injury on his face because of a fall. The patient was initially examined by a medical practitioner in the emergency department of a public hospital. According to 2D cephalometric analysis, no fracture existed. Panoramic radiograph and postero-anterior reverse-town showed bilateral condyle fractures. In addition, a fracture in the left mandibular incisor region could clearly be detected on the panoramic radiograph. For further diagnosis, digital images were taken with CBCT. Cross-sectional views showed two vertical fracture lines on the alveolar bone between teeth numbers 17, 18 and 14, 15. A palatal root fracture was observed associated with tooth number 18. A fracture line in the left mandibular incisor region as well as bilateral condyle fractures could be seen clearly on CBCT views. CBCT is becoming a popular tool in modern dental practise. In the diagnosis of dentoalveolar fractures, CBCT has made it possible for the practitioner to get more detailed information.

  15. Comparative Sensitivity Assessment of Cone Beam Computed Tomography and Digital Radiography for detecting Foreign Bodies.

    PubMed

    Lari, Sima Sadat; Shokri, Abbas; Hosseinipanah, Seyyed Mohammad; Rostami, Shahin; Sabounchi, Shabnam Seyedzadeh

    2016-03-01

    Foreign body detection and determining whether it is adjacent to critical organs has a significant role in its removal. Various imaging techniques have been used to locate foreign bodies. This study aimed to compare cone beam computed tomography (CBCT) and digital radiography for detecting foreign bodies in an in vitro model. Foreign bodies composed of normal glass, barium glass, wood, and stone with two sizes were placed into three different locations of two sheep heads. Digital radiography [lateral cephalometric, submentovertex (SMV)] and CBCT were compared to investigate their sensitivity for detecting foreign bodies. Diagnostic sensitivity of digital radiography in lateral cephalometric view, SMV view, and CBCT for detecting all types of foreign bodies was 67.2, 32.3, and 76.6% respectively. None of these techniques were successful in detecting wood satisfactory. Stone was detected relatively higher than other foreign bodies (82.6%). Diagnostic sensitivity of CBCT in detecting foreign bodies was 100%, except for wood. Accuracy of imaging techniques in detecting foreign bodies according to locations in descending order was lip, mandibular angle, and maxillary sinus. It can be concluded that appropriate amount of radiopacity is enough for CBCT to exactly detect foreign body, regardless of its location or size. In maxillofacial traumatic patients, CBCT seems to be a better and cost-effective technique for detecting hidden foreign bodies than other routine techniques.

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

    PubMed

    Creanga, Adriana Gabriela; Geha, Hassem; Sankar, Vidya; Teixeira, Fabricio B; McMahan, Clyde Alex; Noujeim, Marcel

    2015-09-01

    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.

  17. Upper airway changes after Xbow appliance therapy evaluated with cone beam computed tomography.

    PubMed

    Erbas, Banu; Kocadereli, Ilken

    2014-07-01

    To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients. The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1). Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars. Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.

  18. Evaluation of metal artefact reduction in cone-beam computed tomography images of different dental materials.

    PubMed

    Queiroz, Polyane Mazucatto; Oliveira, Matheus Lima; Groppo, Francisco Carlos; Haiter-Neto, Francisco; Freitas, Deborah Queiroz

    2017-05-23

    The aim of this study is to evaluate the efficacy of metal artefact reduction (MAR) in different dental materials with Picasso Trio cone-beam computed tomography (CBCT) scanner. Three imaging phantoms were custom-made of acrylic resin. Each phantom presented three cylinders of the same material: dental amalgam alloy, gutta-percha or aluminium-copper alloy. CBCT scans were performed on Picasso Trio unit with and without MAR, and artefact expression (standard deviation of grey values) was obtained and compared by Kruskal-Wallis and Student-Newman-Keuls (post hoc) (α = 0.05). Significant reduction of artefact expression (p < 0.05) was observed with MAR on areas around dental alloys. No significant difference (p > 0.05) was observed with or without MAR when gutta-percha was scanned. MAR was effective in reducing artefacts arising from dental alloys on CBCT images. Dental materials of high atomic number and density are widely used in dentistry and can produce artefact that compromise CBCT image. The present study demonstrated that metal artefact reduction algorithm is an effective tool to improve image quality.

  19. A novel method for 4D cone-beam computer-tomography reconstruction

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Park, Justin C.; Chen, Yunmei; Lan, Guanghui; Lu, Bo

    2015-03-01

    Image quality of Four Dimensional Cone-Beam Computer-Tomography (4DCBCT) is severely impaired by highly insufficient amount of projection data available for each phase. Therefore, making good use of limited projection data is crucial to solve this problem. Noticing that usually only a portion of the images is affected by motion, we separate the moving part (different between phases) of the images from the static part (identical among all phases) with the help of prior image reconstructed using all projection data. Then we update the moving part and the static part of images alternatively through solving minimization problems based on a global (use full projection data) and several local (use projection data for respective phase) linear systems. In the other word, we rebuild a large over-determined linear system for static part from the original under-determined systems and we reduce the number of unknowns in the original system for each phase as well. As a result, image quality for both static part and moving part are greatly improved and reliable 4D CBCT images are then reconstructed.

  20. View-dependent geometric calibration for offset flat-panel cone beam computed tomography systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Van-Giang

    2016-04-01

    Geometric parameters that define the geometry of imaging systems are crucial for image reconstruction and image quality in x-ray computed tomography (CT). The problem of determining geometric parameters for an offset flat-panel cone beam CT (CBCT) system, a recently introduced modality with a large field of view, with the assumption of an unstable mechanism and geometric parameters that vary in each view, is considered. To accurately and rapidly find the geometric parameters for each projection view, we use the projection matrix method and design a dedicated phantom that is partially visible in all projection views. The phantom consists of balls distributed symmetrically in a cylinder to ensure the inclusion of the phantom in all views, and a large portion of the phantom is covered in the projection image. To efficiently use calibrated geometric information in the reconstruction process and get rid of approximation errors, instead of decomposing the projection matrix into actual geometric parameters that are manually corrected before being used in reconstruction, as in conventional methods, we directly use the projection matrix and its pseudo-inverse in projection and backprojection operations of reconstruction algorithms. The experiments illustrate the efficacy of the proposed method with a real offset flat-panel CBCT system in dental imaging.

  1. Modulation transfer function evaluation of cone beam computed tomography for dental use with the oversampling method

    PubMed Central

    Watanabe, H; Honda, E; Kurabayashi, T

    2010-01-01

    Objectives The aim was to investigate the possibility of evaluating the modulation transfer function (MTF) of cone beam CT (CBCT) for dental use using the oversampling method. Methods The CBCT apparatus (3D Accuitomo) with an image intensifier was used with a 100 μm tungsten wire placed inside the scanner at a slight angle to the plane perpendicular to the plane of interest and scanned. 200 contiguous reconstructed images were used to obtain the oversampling line-spread function (LSF). The MTF curve was obtained by computing the Fourier transformation from the oversampled LSF. Line pair tests were also performed using Catphan®. Results The oversampling method provided smooth and reproducible MTF curves. The MTF curves revealed that the spatial resolution in the z-axis direction was significantly higher than that in the axial direction. This result was also confirmed by the line pair test. Conclusions MTF analysis was performed successfully using the oversampling method. In addition, this study clarified that the 3D Accuitomo had high spatial resolution, especially in the z-axis direction. PMID:20089741

  2. Facial soft tissue esthetic predictions: validation in craniomaxillofacial surgery with cone beam computed tomography data.

    PubMed

    Bianchi, Alberto; Muyldermans, Louis; Di Martino, Mirko; Lancellotti, Lorenzo; Amadori, Sara; Sarti, Alessandro; Marchetti, Claudio

    2010-07-01

    Facial soft tissue prediction in orthognathic surgery could be a valuable aid to preview the results and determine the best surgical treatment. After many years, considerable difficulties are still present in the prediction of the clinical final aspect. The object of the present study was to validate new soft tissue simulation software (SurgiCase CMF; Materialise, Leuven, Belgium), using data acquired by cone beam computed tomography (CBCT), that makes it possible to foresee the final result. Ten patients with craniomaxillofacial deformations underwent CBCT before surgery. Using the SurgiCase CMF software, the data were reconstructed in 3 dimensions, and various osteotomies were simulated in a 3-dimensional virtual environment by applying different surgical procedures. At 6 months after surgery, the patients underwent repeat CBCT. Thus, it was possible to superimpose the pre- and postoperative CBCT studies to evaluate the reproducibility and reliability of the software. CBCT simulations defined an average absolute error of 0.94 mm, a standard deviation of 0.90 mm, and a percentage of error less than 2 mm of 86.80%. The preliminary results have allowed us to conclude that simulations in orthognathic surgery for skull-maxillofacial deformities using CBCT acquisition are reliable, in addition to the low radiation exposure, and could become the reference standard to plan surgical treatment. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography.

    PubMed

    Kim, Jooseong; Heo, Giseon; Lagravère, Manuel O

    2014-05-01

    To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

  4. Location and classification of Canalis sinuosus for cone beam computed tomography: avoiding misdiagnosis.

    PubMed

    Manhães Júnior, Luiz Roberto Coutinho; Villaça-Carvalho, Maria Fernanda Lima; Moraes, Mari Eli Leonelli; Lopes, Sérgio Lúcio Pereira de Castro; Silva, Milena Bortolotto Felippe; Junqueira, José Luiz Cintra

    2016-01-01

    The aim of this study was to assess the presence, location and, multiplanar distance of the canalis sinuosus (CS) between the incisive foramen and the anterior maxillary alveolar ridge using cone beam computed tomography (CBCT). Therefore, 500 CBCT maxillary images obtained from male and female patients aged 20 to 80 years were selected to assist in the dental treatment. Low-quality tomographic images were discarded. All images were captured with the i-CATTM Classic tomograph and assessed using the XoranCatTM software. The axial sections were analyzed at the incisive foramen in order to verify the CS presence in laterality and location. Furthermore, linear measurements of the nasal cavity floor, buccal cortical bone, and alveolar ridge crest were made. All the collected data were statistically analyzed. Results show a variation of the CS in relation to the classification and distance of anatomical structures, but no significant difference between the right and left sides. It should be highlighted that CBCT is necessary before invasive procedures in order to preserve important anatomical structures. In conclusion, the location of the CS varies in relation to the alveolar ridge crest and buccal cortical bone, assuming that it is going to be located by the upper lateral incisor palatine.

  5. Assessment of the role of cone beam computed sialography in diagnosing salivary gland lesions

    PubMed Central

    Abdel-Wahed, Nagla'a; Abo-Taleb, Noha Saleh Mahmoud

    2013-01-01

    Purpose The purpose of this study was to assess cone-beam computed (CBCT) sialography imaging in the detection of different changes associated with lesions of salivary glands. Materials and Methods This study consisted of 8 cases with signs and symptoms from salivary gland lesions. Conventional sialography using digital panoramic and lateral oblique radiographs and CBCT sialography were performed for each subject. The radiographs were evaluated by 3 radiologists independently of each other. The results were compared between conventional sialography and CBCT sialography in the evaluation of various lesions associated with the salivary glands. Results There was an agreement between the radiologists in interpreting the lesions that affected salivary glands with both techniques. The detection of the presence of stones or filling defects, stenosis, ductal evagination, dilatation, and space occupying lesions was 83% for conventional sialography compared with CBCT sialography. CBCT sialography was superior to conventional sialography in revealing stones, stenosis, and strictures, especially in the second and third order branches. Conclusion It would be advisable to perform CBCT sialography in cases of obstructive salivary gland diseases for better demonstration of the ductal system of the gland. PMID:23524990

  6. Comparing the Coronal Flaring Efficacy of Five Different Instruments Using Cone-Beam Computed Tomography

    PubMed Central

    Homayoon, Amin; Hamidi, Mahmood Reza; Haddadi, Azam; Madani, Zahra Sadat; Moudi, Ehsan; Bijani, Ali

    2015-01-01

    Introduction: Fearless removal of tooth structure during canal preparation and shaping has negative effects on the prognosis of treatment. On the other hand, sufficient pre-enlargement facilitates exact measurement of the apical size. The present in vitro study aimed to compare the efficacy of Gates-Glidden drills, K3, ProTaper, FlexMaster and RaCe instruments in dentin removal during coronal flaring using cone-beam computed tomography (CBCT). Methods and Materials: A total of 40 mandibular molars were selected and the coronal areas of their mesiobuccal and mesiolingual root canals were randomly prepared with either mentioned instruments. Pre- and post-instrumentation CBCT images were taken and the thickness of canal walls was measured in 1.5- and 3-mm distances from the furcation area. Data were analyzed using the one-way ANOVA. Tukey’s post hoc tests were used for two-by-two comparisons. Results: At 1.5-mm distance, there was no significant difference between different instruments. However, at 3-mm distances, Gates-Glidden drills removed significantly more dentin compared to FlexMaster files (mean=0.18 mm) (P<0.02); however, two-by-two comparisons did not reveal any significant differences between the other groups. Conclusion: All tested instruments can be effectively used in clinical settings for coronal pre-enlargement. PMID:26525955

  7. Developments of metal artifact reduction methods of cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Shih, Kun-Long; Jin, Shih-Chun D.; Chen, Jyh-Cheng

    2014-09-01

    While clinical applications of cone-beam computed tomography (CBCT) have expanded, current CBCT technology has limitations due to the streak artifacts caused by metallic objects. The aim of this work was to develop an efficient and accurate metal data interpolation in sinogram domain to achieve artifact suppression and to improve CT image quality. In this study, we propose three interpolation methods for the metal projection data. Metal objects are segmented in raw data and replacement of the segmented regions by new values is done using three interpolation schemes, (1) replacing the raw data by the simple threshold value (thresholding method), (2) reducing the raw data to half of the value which is over threshold value (modification method), (3) using the inpainting interpolation (inpainting method). Our references are the CBCT images of the phantoms without the metal implants. The performance was evaluated by comparing the differences of root mean square error (RMSE) before and after metal artifact reduction (MAR). All the metal artifacts were reduced effectively. Metal artifacts reduction using method (1) performs the best, which improve the differences of RMSE more than 60%. This study indicates that metal artifacts can be reduced effectively by manipulating metal projection data.

  8. Pharyngeal airway volume and shape from cone-beam computed tomography: Relationship to facial morphology

    PubMed Central

    Grauer, Dan; Cevidanes, Lucia S. H.; Styner, Martin A.; Ackerman, James L.; Proffit, William R.

    2010-01-01

    Introduction The aim of this study was to assess the differences in airway shape and volume among subjects with various facial patterns. Methods Cone-beam computed tomography records of 62 nongrowing patients were used to evaluate the pharyngeal airway volume (superior and inferior compartments) and shape. This was done by using 3-dimensional virtual surface models to calculate airway volumes instead of estimates based on linear measurements. Subgroups of the sample were determined by anteroposterior jaw relationships and vertical proportions. Results There was a statistically significant relationship between the volume of the inferior component of the airway and the anteroposterior jaw relationship (P = 0.02), and between airway volume and both size of the face and sex (P = 0.02, P = 0.01). No differences in airway volumes related to vertical facial proportions were found. Skeletal Class II patients often had forward inclination of the airway (P <0.001), whereas skeletal Class III patients had a more vertically oriented airway (P = 0.002). Conclusions Airway volume and shape vary among patients with different anteroposterior jaw relationships; airway shape but not volume differs with various vertical jaw relationships. The methods developed in this study make it possible to determine the relationship of 3-dimensional pharyngeal airway surface models to facial morphology, while controlling for variability in facial size. PMID:19962603

  9. Localization of impacted maxillary canines using cone beam computed tomography. Review of the literature

    PubMed Central

    Rossini, Giulia; Cavallini, Costanza; Cassetta, Michele; Galluccio, Gabriella; Barbato, Ersilia

    2012-01-01

    Summary This review analyzed the literature focused on Cone- Beam Computed Tomography (CBCT) diagnostic accuracy and efficacy in detecting impacted maxillary canines, and evaluated the possible advantages in using CBCT technique compared with traditional radiographs. PubMed and Embase searches were performed selecting papers since 1998 up to September 2011, moreover reference lists were hand searched. Two reviewers selected relevant publications on the basis of predetermined inclusion criteria. The literature search yielded 94 titles, of which 5 were included in the review. Three studies used CBCT technique to 3D localize maxillary impacted canines and assess root resorption of adjacent teeth. Other two publications compared traditional radiographs with CBCT images in the diagnosis of maxillary impacted canines. Only three studies presented the results using statistical analysis. The present review highlighted that the use of CBCT has a potential diagnostic effect and may influence the outcome of treatment when compared with traditional panoramic radiography for the assessment of impacted maxillary canines. Furthermore it underlines the need of future studies performed according with high level methodological standards, investigating diagnostic accuracy and effectiveness of CBCT in the diagnosis of maxillary impacted teeth. PMID:22783450

  10. Cone beam computed tomography in dental education: a survey of US, UK, and Australian dental schools.

    PubMed

    Parashar, Vijay; Whaites, Eric; Monsour, Paul; Chaudhry, Jahanzeb; Geist, James R

    2012-11-01

    Cone beam computed tomography (CBCT) is an excellent three-dimensional (3D) imaging modality. Traditional dental education has focused on teaching conventional (2D) imaging. The aims of this survey-based study were therefore to evaluate the incorporation of CBCT teaching in both the predoctoral/undergraduate (D.D.S./D.M.D./B.D.S.) and postgraduate/residency specialty training curricula in dental schools in the United States, the United Kingdom, and Australia. A nine-question survey form was electronically mailed to fifty-seven schools in the United States, sixteen schools in the United Kingdom, and seven schools in Australia. Fifty U.S. dental schools (89 percent), ten U.K. dental schools (62.5 percent), and one Australian dental school (14 percent) presently have CBCT equipment. The majority of responding schools do not include instruction in higher level use of this technology for undergraduate/predoctoral students, raising questions as to whether these students are adequately trained on qualification. Larger numbers of schools reported providing this training to residents in specialty programs. A similar trend was noticed in U.S., British, and Australian dental education. If general dentists are to be permitted to purchase and use CBCT equipment, inclusion of CBCT in dental education is an absolute requirement to prepare future dental practitioners to apply 3D imaging appropriately for diagnosis and treatment planning.

  11. Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography.

    PubMed

    Choi, Mi-Ree; Moon, Young-Mi; Seo, Min-Seock

    2015-12-01

    This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

  12. Immediate implant placement: the fate of the buccal crest. A retrospective cone beam computed tomography study.

    PubMed

    Groenendijk, E; Staas, T A; Graauwmans, F E J; Bronkhorst, E; Verhamme, L; Maal, T; Meijer, G J

    2017-07-19

    This retrospective study aimed to analyse the fate of the buccal crest after immediate implant placement (IIP) through the use of cone beam computed tomography (CBCT). In 16 consecutive patients, an implant was placed in a more palatal position after extraction, thereby creating a gap of at least 2mm between the implant and the buccal crest. Subsequently, this gap was filled with a bone substitute. Preoperatively, immediate postoperatively, and late postoperatively, a CBCT was made to measure the thickness of the buccal crest. After application of the bone substitute, the buccal crest increased in thickness from 0.9mm to 2.4mm (mean). At a mean of 103 weeks after IIP, late postoperative CBCT scans showed that the thickness of the buccal crest was compacted to 1.8mm. In the same period, the height of the buccal crest increased by 1.6mm (mean) to, on average, 1.2mm above the implant shoulder. The aesthetic outcome was analysed using the White and Pink Esthetic Score (WES and PES). Both scored high: 8.4 and 11.8, respectively. Within the limitations of this study, the results of this IIP protocol are promising. Long-term prospective research on this topic on a large number of patients is necessary. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Cone beam computed tomography and histological evaluations of a straight electrode array positioning in temporal bones.

    PubMed

    Mosnier, Isabelle; Célérier, Charlotte; Bensimon, Jean-Loup; de Seta, Daniele; Sterkers, Olivier; Nguyen, Yann; Bernardeschi, Daniele

    2017-03-01

    CBCT allows a precise evaluation of the dimensions and of the shape of the cochlear duct that is of primary importance for the choice of the length and the design of the electrode array. This radio-histological study confirms that CBCT is a reliable tool to be used in clinical studies to evaluate the position of straight electrode arrays within the cochlear scala. To validate the reliability of cone beam computed tomography (CBCT) in the evaluation of cochlear anatomy and positioning of a straight electrode array, by comparing radiological images to histological analysis of cochlear implanted temporal bones. Eight temporal bones for four subjects were analysed before and after cochlear implantation with a straight electrode array. The size of the cochlea, the dimensions, and shape of the cochlear duct at 180° and 360° were evaluated on CBCT performed before implantation. Temporal bones then underwent histological analysis to determine the position of the electrode array. Scalar localization of the electrode array was assessed on CBCT performed after implantation, and compared with histological study. CBCT is a reliable radiological technique to differentiate variability not only of cochlear dimensions, but also of size and shape of the cochlea. Histological analysis confirmed the scalar position of the electrode array assessed by the CBCT in 7/8 temporal bones, but soft tissue trauma such as dissection of the spiral ligament was not identified by the CBCT.

  14. Fast three-dimensional superimposition of cone beam computed tomography for orthopaedics and orthognathic surgery evaluation

    PubMed Central

    Weissheimer, A.; Menezes, L. M.; Koerich, L.; Pham, J.; Cevidanes, L. H. S.

    2015-01-01

    The aim of this study was to validate a method for fast three-dimensional (3D) superimposition of cone beam computed tomography (CBCT) in growing patients and adults (surgical cases). The sample consisted of CBCT scans of 18 patients. For 10 patients, as the gold standard, the spatial position of the pretreatment CBCT was reoriented, saved as a reoriented volume, and then superimposed on the original image. For eight patients, four non-growing and four growing, the pre- and post-treatment scans were superimposed. Fast voxel-based superimposition was performed, with registration at the anterior cranial base. This superimposition process took 10–15 s. The fit of the cranial base superimposition was verified by qualitative visualization of the semi-transparent axial, sagittal, and coronal cross-sectional slices of all corresponding anatomical structures. Virtual 3D surface models of the skull were generated via threshold segmentation, and superimposition errors in the reoriented models and the results of treatment for the treated cases were evaluated by 3D surface distances on colour-coded maps. The superimposition error of the spatial reorientation and for growing and non-growing patients was <0.5 mm, which is acceptable and clinically insignificant. The voxel-based superimposition method evaluated was reproducible in different clinical conditions, rapid, and applicable for research and clinical practice. PMID:25935632

  15. Endodontic application of cone-beam computed tomography in South Korea.

    PubMed

    Kim, Seonah

    2012-02-01

    This study aimed to investigate the incidence of cone-beam computed tomography (CBCT) associated with endodontic procedures during 2009 in South Korea and to retrospectively evaluate information from CBCT with large field of view (FOV), which is popular in South Korea. The Health Insurance Review and Assessment agency, which reviews all medical and dental expenses covered under the Korean National Health Insurance (NHI) system, was queried for data on the nationwide number of CBCTs associated with some treatment procedures. To compare digital periapical radiography and CBCT retrospectively, 470 roots of 257 root canal-infected teeth were enrolled. In total, 13,209 cases of NHI-covered CBCT were performed in South Korea during 2009, excluding cases for implant restoration and orthodontics. In total, 1253 and 95 CBCT cases were combined with root canal length measuring and apicoectomy, respectively. In a retrospective comparison, CBCT with large FOV provided more information about the presence of apical periodontitis, distortion of cortical bone, and identification of root compared with digital periapical radiography. CBCT with large FOV is useful in nonsurgical endodontic treatment and provides more information compared with digital periapical radiography. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    PubMed Central

    SCHWARTZ, João Paulo; RAVELI, Taísa Boamorte; ALMEIDA, Kélei Cristina de Mathias; SCHWARTZ-FILHO, Humberto Osvaldo; RAVELI, Dirceu Barnabé

    2015-01-01

    Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT). Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years) with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0) and after Herbst treatment (T1). All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%. Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders. Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance. PMID:26537718

  17. Cone-beam computed tomography as a surgical guide to impacted anterior teeth

    PubMed Central

    Jeremias, Fabiano; Fragelli, Camila Maria Bullio; Mastrantonio, Simone Di Salvo; dos Santos-Pinto, Lourdes; dos Santos-Pinto, Ary; Pansani, Cyneu Aguiar

    2016-01-01

    Surgical procedure for removal of impacted teeth is a challenge for clinicians as it involves accuracy in the diagnosis and localization of the dental elements. The cone-beam computed tomography (CBCT), compared to the conventional radiography, has a greater potential to provide complementary information because of its three-dimensional (3D) images, reducing the possibility of failures in surgical procedures. Two 10-year-old boys presented with aesthetic issues associated with the juxtaposition of ectopic teeth with the permanent ones. Both two-dimensional and 3D preoperative radiographic diagnostic sets were produced. The occlusal and panoramic radiographs were not enough for proper localization of impacted incisors. Thus, the CBCT was used as a surgical guide. After 2 years of longitudinal following, no lesion was recorded, and the orthodontic treatment has proven successful. In all cases, CBCT contributed to both diagnosis and correct localization of supernumerary teeth, aiding the professional in the treatment planning, and consequently in the clinical success. The surgeries were completely safe, avoiding damage in noble structures, and providing a better recovering of the patients. PMID:26962322

  18. Accuracy and precision of cone beam computed tomography in periodontal defects measurement (systematic review)

    PubMed Central

    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

  19. Digital orthodontic radiographic set versus cone-beam computed tomography: an evaluation of the effective dose

    PubMed Central

    Chinem, Lillian Atsumi Simabuguro; Vilella, Beatriz de Souza; Maurício, Cláudia Lúcia de Pinho; Canevaro, Lucia Viviana; Deluiz, Luiz Fernando; Vilella, Oswaldo de Vasconcellos

    2016-01-01

    ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digital radiographic methods (panoramic, lateral cephalometric and periapical) with cone-beam computed tomography (CBCT). Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA), representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany), Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany) and i-CAT (Imaging Sciences International, Hatfield, PA, USA). The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP) issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990) and 47.2% (ICRP 2007) of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination. PMID:27653266

  20. Fast three-dimensional superimposition of cone beam computed tomography for orthopaedics and orthognathic surgery evaluation.

    PubMed

    Weissheimer, A; Menezes, L M; Koerich, L; Pham, J; Cevidanes, L H S

    2015-09-01

    The aim of this study was to validate a method for fast three-dimensional (3D) superimposition of cone beam computed tomography (CBCT) in growing patients and adults (surgical cases). The sample consisted of CBCT scans of 18 patients. For 10 patients, as the gold standard, the spatial position of the pretreatment CBCT was reoriented, saved as a reoriented volume, and then superimposed on the original image. For eight patients, four non-growing and four growing, the pre- and post-treatment scans were superimposed. Fast voxel-based superimposition was performed, with registration at the anterior cranial base. This superimposition process took 10-15s. The fit of the cranial base superimposition was verified by qualitative visualization of the semi-transparent axial, sagittal, and coronal cross-sectional slices of all corresponding anatomical structures. Virtual 3D surface models of the skull were generated via threshold segmentation, and superimposition errors in the reoriented models and the results of treatment for the treated cases were evaluated by 3D surface distances on colour-coded maps. The superimposition error of the spatial reorientation and for growing and non-growing patients was <0.5mm, which is acceptable and clinically insignificant. The voxel-based superimposition method evaluated was reproducible in different clinical conditions, rapid, and applicable for research and clinical practice.

  1. Management of Oehler's Type III Dens Invaginatus Using Cone Beam Computed Tomography

    PubMed Central

    Ranganathan, Jaya; Rangarajan Sundaresan, Mohan Kumar; Ramasamy, Srinivasan

    2016-01-01

    Dens Invaginatus is a dental malformation that poses diagnostic difficulties in the clinical context. This anomaly may increase the risk of pulp disease and can potentially complicate endodontic procedure due to the aberrant root canal anatomy. Compared to conventional radiographs, three-dimensional images obtained with Cone Beam Computed Tomography (CBCT) are invaluable in the diagnosis of the extent of this anomaly and in the appropriate treatment planning. Oehler's classification (1957) for Dens Invaginatus (DI) into three types depending on the depth of the invagination has been used for treatment planning. Of the three types Type III DI is characterized by infolding of the enamel into the tooth up to the root apex and is considered as the most severe variant of DI and hence the most challenging to treat endodontically, due to the morphological complexities. This report describes a case of Oehler's Type III DI in a necrotic permanent maxillary lateral incisor in which CBCT images played a key role in diagnosis and treatment planning. The case was managed successfully by a combination of nonsurgical and surgical endodontic therapy with orthograde and retrograde thermoplastic gutta percha obturation. PMID:27069697

  2. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

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

    PubMed Central

    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 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. Notwithstanding, 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

  4. Four-dimensional cone-beam computed tomography using an on-board imager.

    PubMed

    Li, Tianfang; Xing, Lei; Munro, Peter; McGuinness, Christopher; Chao, Ming; Yang, Yong; Loo, Bill; Koong, Albert

    2006-10-01

    On-board cone-beam computed tomography (CBCT) has recently become available to provide volumetric information of a patient in the treatment position, and holds promises for improved target localization and irradiation dose verification. The design of currently available on-board CBCT, however, is far from optimal. Its quality is adversely influenced by many factors, such as scatter, beam hardening, and intra-scanning organ motion. In this work we quantitatively study the influence of organ motion on CBCT imaging and investigate a strategy to acquire high quality phase-resolved [four-dimensional (4D)] CBCT images based on phase binning of the CBCT projection data. An efficient and robust method for binning CBCT data according to the patient's respiratory phase derived in the projection space was developed. The phase-binned projections were reconstructed using the conventional Feldkamp algorithm to yield 4D CBCT images. Both phantom and patient studies were carried out to validate the technique and to optimize the 4D CBCT data acquisition protocol. Several factors that are important to the clinical implementation of the technique, such as the image quality, scanning time, number of projections, and radiation dose, were analyzed for various scanning schemes. The general references drawn from this study are: (i) reliable phase binning of CBCT projections is accomplishable with the aid of external or internal marker and simple analysis of its trace in the projection space, and (ii) artifact-free 4D CBCT images can be obtained without increasing the patient radiation dose as compared to the current 3D CBCT scan.

  5. Radiation Dose From Cone Beam Computed Tomography for Image-Guided Radiation Therapy

    SciTech Connect

    Kan, Monica W.K. Leung, Lucullus H.T.; Wong, Wicger; Lam, Nelson

    2008-01-01

    Purpose: To perform a comprehensive study on organ absorbed doses and effective doses from cone beam computed tomography (CBCT) for three different treatment sites. Methods and Materials: An extensive set of dosimetric measurements were performed using a widely used CBCT system, the On-Board Imager (OBI). Measurements were performed using a female anthropomorphic phantom with thermoluminescent dosimeters (TLD). The effective doses to the body and the absorbed doses to 26 organs were reported using two different technical settings, namely, the standard mode and the low-dose mode. The measurements were repeated for three different scan sites: head and neck, chest, and pelvis. Comparisons of patient doses as well as image quality were performed among the standard mode CBCT, low-dose mode CBCT, and fan beam CT. Results: The mean skin doses from standard mode CBCT to head and neck, chest and pelvis were 6.7, 6.4, and 5.4 cGy per scan, respectively. The effective doses to the body from standard mode CBCT for imaging of head and neck, chest, and pelvis were 10.3, 23.7, and 22.7 mSv per scan, respectively. Patient doses from low-dose mode CBCT were approximately one fifth of those from standard mode CBCT. Conclusions: Patient position verification by standard mode CBCT acquired by OBI on a daily basis could increase the secondary cancer risk by up to 2% to 4%. Therefore lower mAs settings for daily CBCT should be considered, especially when bony anatomy is the main interest.

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

    SciTech Connect

    Ding, George X. Coffey, Charles W.

    2009-02-01

    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.

  7. Daily online cone beam computed tomography to assess interfractional motion in patients with intact cervical cancer.

    PubMed

    Tyagi, Neelam; Lewis, John H; Yashar, Catheryn M; Vo, Daniel; Jiang, Steve B; Mundt, Arno J; Mell, Loren K

    2011-05-01

    To quantify interfraction motion in patients with intact cervical cancer and assess implications for clinical target volume (CTV) coverage and required planning margins. We analyzed 10 patients undergoing external beam radiotherapy using online cone beam computed tomography (CBCT) before each fraction. CTVs were contoured on the planning CT and on each CBCT. Each CBCT was rigidly registered to the planning CT with respect to bony anatomy. The CTV from each CBCT was projected onto the planning CT and compared to the CTV from the planning CT. Uniform three-dimensional expansions were applied to the planning CTV to assess required planning margins. For each fraction, the minimum margin required to encompass the CTV was calculated, and the volume of CTV (on the CBCT) encompassed by the PTV was determined as a function of margin size. A uniform CTV planning treatment volume margin of 15 mm would have failed to encompass the CTV in 32% of fractions. The mean volume of CTV missed, however, was small (4 cc). The mean planning margin (across patients and fractions) required to encompass the CTV was 15 mm. Variation in margin estimates was high, with interpatient variation being the predominant component. Increased rectal volume was associated with posterior (p < 0.0001) and superior (p = 0.0004) shifts in the CTV, whereas increased bladder volume was associated with superior shifts (p < 0.0001). Interfraction motion results in a high probability of missing the CTV using conventional planning margins, but the volume of CTV missed is small. Adaptive radiotherapy approaches are needed to improve treatment accuracy. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Daily Online Cone Beam Computed Tomography to Assess Interfractional Motion in Patients With Intact Cervical Cancer

    SciTech Connect

    Tyagi, Neelam; Lewis, John H.; Yashar, Catheryn M.; Vo, Daniel; Jiang, Steve B.; Mundt, Arno J.; Mell, Loren K.

    2011-05-01

    Purpose: To quantify interfraction motion in patients with intact cervical cancer and assess implications for clinical target volume (CTV) coverage and required planning margins. Methods and Materials: We analyzed 10 patients undergoing external beam radiotherapy using online cone beam computed tomography (CBCT) before each fraction. CTVs were contoured on the planning CT and on each CBCT. Each CBCT was rigidly registered to the planning CT with respect to bony anatomy. The CTV from each CBCT was projected onto the planning CT and compared to the CTV from the planning CT. Uniform three-dimensional expansions were applied to the planning CTV to assess required planning margins. For each fraction, the minimum margin required to encompass the CTV was calculated, and the volume of CTV (on the CBCT) encompassed by the PTV was determined as a function of margin size. Results: A uniform CTV planning treatment volume margin of 15 mm would have failed to encompass the CTV in 32% of fractions. The mean volume of CTV missed, however, was small (4 cc). The mean planning margin (across patients and fractions) required to encompass the CTV was 15 mm. Variation in margin estimates was high, with interpatient variation being the predominant component. Increased rectal volume was associated with posterior (p < 0.0001) and superior (p = 0.0004) shifts in the CTV, whereas increased bladder volume was associated with superior shifts (p < 0.0001). Conclusions: Interfraction motion results in a high probability of missing the CTV using conventional planning margins, but the volume of CTV missed is small. Adaptive radiotherapy approaches are needed to improve treatment accuracy.

  9. Evaluation of Root Fracture in endodontically treated Teeth using Cone Beam Computed Tomography.

    PubMed

    Tiepo, Mariana; Magrin, Gabriel; Kovalik, Ana C; Marmora, Belkiss; Silva, Milena F; Raitz, Ricardo

    2017-02-01

    Our objective was to perform an in vitro evaluation of root fracture in endodontically treated teeth using two cone beam computed tomography (CBCT) machines. The sample comprised 86 single-rooted human premolars that had been fractured by a universal testing machine. The tomographic images were acquired using an Orthopantomograph OP300(®) and an Orthophos XG 3D(®) and evaluated by three examiners, by means of specific software. The teeth were classified into presence or absence of root fracture, then the root third where the fracture occurred, was determined. With regard to the detection of the fracture, the Kappa statistic was used for intra and interexaminer repro-ducibility at two distinct points in time. Chi-squared test was employed to analyze the sensitivity and specificity of the two tomographs (p < 0.05). The results showed a good or excellent Kappa index between examiners. As for the absolute frequency, the sensitivity (0.6) of the Orthophos XG 3D(®) equipment was superior, while specificity (0.91) was higher with the Orthopantomograph OP300(®). On the receiver operating characteristics curve, moderate performance was found with an accuracy of 0.73 (OrthopantomographOP300(®)) and 0.74 (Orthophos XG 3D(®)) respectively. As far as the location of the root fracture is concerned, moderate agreement was verified using the Kappa statistic (k = 0.56). Although the regular CBCTs represent the imaging examination of choice for assisting root fracture diagnosis in endodontically treated teeth, their performance in this study demonstrated an imprecise diagnosis of fractures in a good many cases, irrespective of the tomography machine used. An early and precise detection of root fractures is of the utmost clinical importance, but the radiopaque and/or metallic filling materials in the CBCT viewing field may generate artifacts, known as the beam-hardening effect, which could compromise root fracture detection.

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

    NASA Astrophysics Data System (ADS)

    Yang, Yidong; Armour, Michael; Kang-Hsin Wang, Ken; 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

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

    PubMed

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

    2015-07-07

    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.

  12. Impacted lower third molar fused with a supernumerary tooth--diagnosis and treatment planning using cone-beam computed tomography.

    PubMed

    Ferreira-Junior, Osny; de Avila, Luciana Dorigatti; Sampieri, Marcelo Bonifácio da Silva; Dias-Ribeiro, Eduardo; Chen, Wei-liang; Fan, Song

    2009-12-01

    This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan's radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography-which provides precise three-dimensional information-was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomography.

  13. Management of synodontia between dilacerated permanent maxillary central incisor and supernumerary tooth with aid of cone-beam computed tomography

    PubMed Central

    Das, Suroopa; Warhadpande, Manjusha M.; Redij, Saurabh Anil; Sabir, Husain; Shirude, Tushar

    2015-01-01

    A malformed tooth characterized by one or more developmental disturbances is often difficult to treat. When such teeth are present in anterior region, they pose a technical challenge for the clinician to restore esthetics as well as function. This case describes endodontic, surgical, and restorative management of fused and dilacerated maxillary central incisor. Cone-beam computed tomography (CBCT) was used in the present case to aid in understanding of complicated tooth morphology and managing the case successfully. PMID:25829699

  14. Surface analysis of study models generated from OrthoCAD and cone-beam computed tomography imaging.

    PubMed

    Lightheart, Kurtis G; English, Jeryl D; Kau, Chung H; Akyalcin, Sercan; Bussa, Harry I; McGrory, Kathleen R; McGrory, Kevin J

    2012-06-01

    The purpose of this research was to determine the accuracy of digital models generated by cone-beam computed tomography and compare it with that of OrthoCAD models (Cadent, Carlstadt, NJ) for orthodontic diagnosis and treatment planning by using surface area analysis. Two sets of maxillary and mandibular digital models of 30 subjects were obtained. The models were made from impressions scanned with OrthoCAD and by conversion of related cone-beam computed tomography files. Each patient's matched pairs of maxillary and mandibular models were superimposed by using a software program and a best-fit algorithm; surface-to-surface analysis was then performed. The average linear differences between the 2 files at all points on the surfaces were measured, and tolerance levels of 0.25, 0.5, 0.75, 1.0, 1.25, and 1.5 mm were set to determine the surface correlation amounts between the 2 files. Additionally, 6 linear measurements from predetermined landmarks were also measured and analyzed. The average maxillary model linear difference was 0.28 to 0.60 mm, whereas the average mandibular model linear difference ranged between 0.34 and 0.61 mm. Greater than a 90% surface correlation was obtained on average at 1.00 mm in the maxillary models and at 1.25 mm in the mandibular models. The mean differences obtained from the linear measurements of the maxillary and mandibular models were 0.071 and 0.018 mm, respectively. Surface-to-surface analysis of OrthoCAD and digital models generated by cone-beam computed tomography pointed to a fair overlap between the protocols. The accuracy of digital models generated by cone-beam computed tomography is adequate for initial diagnosis and treatment planning in orthodontics. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  15. Conservative Treatment of an Invaginated Maxillary Lateral Incisor with a C-shaped Canal Using Cone-Beam Computed Tomography

    PubMed Central

    Forghani, Maryam; Moghim Farooji, Elaheh; Abuchenari, Javad; Bidar, Maryam; Eslami, Neda

    2015-01-01

    This report describes the non-surgical treatment of an invaginated maxillary lateral incisor with two fused roots. The mesial root had a C-shaped canal, while the distal one had a type III dens invagination. Cone-beam computed tomography (CBCT) was used to help with the diagnosis and treatment decision making. Clinical and radiographic follow-up revealed satisfactory periapical repair and absence of symptoms after 15 months. PMID:26576164

  16. Image reconstruction in circular cone-beam computed tomography by constrained, total-variation minimization

    PubMed Central

    Sidky, Emil Y.; Pan, Xiaochuan

    2009-01-01

    An iterative algorithm, based on recent work in compressive sensing, is developed for volume image reconstruction from a circular cone-beam scan. The algorithm minimizes the total-variation (TV) of the image subject to the constraint that the estimated projection data is within a specified tolerance of the available data and that the values of the volume image are non-negative. The constraints are enforced by use of projection onto convex sets (POCS) and the TV objective is minimized by steepest descent with an adaptive step-size. The algorithm is referred to as adaptive-steepest-descent-POCS (ASD-POCS). It appears to be robust against cone-beam artifacts, and may be particularly useful when the angular range is limited or when the angular sampling rate is low. The ASD-POCS algorithm is tested with the Defrise disk and jaw computerized phantoms. Some comparisons are performed with the POCS and expectation-maximization (EM) algorithms. Although the algorithm is presented in the context of circular cone-beam image reconstruction, it can also be applied to scanning geometries involving other x-ray source trajectories. PMID:18701771

  17. Observation of the pulp horn by swept source optical coherence tomography and cone beam computed tomography

    NASA Astrophysics Data System (ADS)

    Iino, Yoshiko; Yoshioka, Toshihiko; Hanada, Takahiro; Ebihara, Arata; Sunakawa, Mitsuhiro; Sumi, Yasunori; Suda, Hideaki

    2015-02-01

    Cone-beam computed tomography (CBCT) is one of the most useful diagnostic techniques in dentistry but it involves ionizing radiation, while swept source optical coherence tomography (SS-OCT) has been introduced recently as a nondestructive, real-time, high resolution imaging technique using low-coherence interferometry, which involves no ionizing radiation. The purpose of this study was to evaluate the ability of SS-OCT to detect the pulp horn (PH) in comparison with that of CBCT. Ten extracted human mandibular molars were used. After horizontally removing a half of the tooth crown, the distance from the cut dentin surface to PH was measured using microfocus computed tomography (Micro CT) (SL) as the gold standard, by CBCT (CL) and by SS-OCT (OL). In the SS-OCT images, only when PH was observed beneath the overlying dentin, the distance from the cut dentin surface to PH was recorded. If the pulp was exposed, it was defined as pulp exposure (PE). The results obtained by the above three methods were statistically analyzed by Spearman's rank correlation coefficient at a significance level of p < 0.01. SS-OCT detected the presence of PH when the distance from the cut dentin surface to PH determined by SL was 2.33 mm or less. Strong correlations of the measured values were found between SL and CL (r=0.87), SL and OL (r=0.96), and CL and OL (r=0.86). The results showed that SS-OCT images correlated closely with CBCT images, suggesting that SS-OCT can be a useful tool for the detection of PH.

  18. Length and anatomic routes of the greater palatine canal as observed by cone beam computed tomography

    PubMed Central

    Sheikhi, Mahnaz; Zamaninaser, Asieh; Jalalian, Faranak

    2013-01-01

    Background: Greater palatine canal is used for maxillary nerve block. This procedure has some complications such as proptosis, blindness, and intravascular injection. This study aimed to determine the mean greater palatine canal length (CL) and its typical anatomic routes, as well as provide a reliable facial index for computing the CL by using cone beam computed tomography (CBCT) data. Materials and Methods: A total of 138 CBCT scans (65 females and 73 males) were evaluated. The path of the canal and the CL were determined by sex, age, and side. The mean distance from the inferior border of the infraorbital foramen (IOF) to the crest of alveolar bone between maxillary premolar(CMP) was measured and compared with the CL. Paired t-tests, independent t-test, and one-way analysis of variance (ANOVA) were used for statistical analysis. Results: The mean of CL was 31.82 ± 1.37 mm (31.70 ± 2.44 mm on the right side and 31.94 ± 2.40 mm on the left side), and the values were 32.49 ± 2.37 mm in males and 30.55 ± 1.76 mm among females (P = 0.001). The mean distance from the IOF to the CMP was 32.01 ± 2.18 mm, which was not significantly different to the CL (P = 0.336). Conclusions: The mean CL was significantly different according to sex and side. The mean distance from the IOF to CMP was significantly different according to sex. On comparing the mean distance from the IOF to the CMP with the CL, no significant difference was observed. Therefore, the mean distance from the IOF to CMP may be a reliable clinical index. PMID:23946729

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

    PubMed Central

    Kim, Min-Sung; Kim, Bok-Yeol; Choi, Hwa-Young; Choi, Yoon-Joo; Oh, Song-Hee; Kang, Ju-Hee; Lee, Sae-Rom; Kang, Ju-Han; Kim, Gyu-Tae; Choi, Yong-Suk

    2015-01-01

    Purpose 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. Materials and Methods 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. Results 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. Conclusion 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. PMID:25793181

  20. Detection of horizontal root fracture using four different protocols of cone-beam computed tomography.

    PubMed

    Salineiro, Fernanda Cristina Sales; Pinheiro, Lucas Rodrigues; dos Santos Júnior, Oséas; Cavalcanti, Marcelo Gusmão Paraiso

    2015-01-01

    The purpose of this study was to analyze four different cone-beam computed tomography (CBCT) protocols to identify horizontal root fractures (HRF) in endodontically treated teeth, with or without the presence of a metallic post. Thirty extracted single-rooted human premolars were treated endodontically. Afterwards, an observer induced a horizontal fracture in 15 teeth. Each tooth was inserted in an empty mandibular socket and submitted to a computed tomography scan taken with and without the metallic post. The acquisition followed four different protocols, with different fields of view (FOV) and voxel sizes, as follows: FOV 6 X 16 cm/0.2 mm voxel; FOV 6 X 16 cm/0.25 mm voxel; FOV 8 X 8 cm/0.2 mm voxel; FOV 8 X 8 cm/0.25 mm voxel. Two observers checked all the acquisitions within a two-week interval, and the values of sensitivity, specificity, accuracy and kappa were calculated. The sensitivity, specificity and accuracy values were better for the 8 X 8 cm/0.2 mm and 16 X 6 cm/0.25 mm protocols, ranging from 0.60 to 0.86 and 0.53 to 0.80, respectively. The intra- and interobserver concordance ranged from 0.65 to 0.72. The protocols where FOV and voxel were proportional showed better results. The 8 x 8 cm/0.2 mm protocol had the least interference from the metallic artifact. All four protocols showed a decline in values in the presence of the metallic artifact.

  1. Agreement between cone-beam computed tomography and nasoendoscopy evaluations of adenoid hypertrophy.

    PubMed

    Major, Michael P; Witmans, Manisha; El-Hakim, Hamdy; Major, Paul W; Flores-Mir, Carlos

    2014-10-01

    The goals of this study were to evaluate (1) the reliability and accuracy of cone-beam computed tomography (CBCT) for assessing adenoid size compared with nasoendoscopy and (2) the influence of clinical experience on CBCT diagnosis. Adenoid size was graded on a 4-point scale for CBCT and nasoendoscopy by a pediatric otolaryngologist. Reliability was assessed with intraobserver and interobserver agreement. Accuracy was assessed with agreement between CBCT and nasoendoscopy, plus sensitivity and specificity analyses. The CBCT assessments were completed by a team of 4 evaluators: an oral and maxillofacial radiologist, an airway orthodontist who participates in the multidisciplinary team, an academic orthodontist whose primary research is in 3-dimensional imaging, and a highly experienced private practice orthodontist comfortable with CBCT imaging. Each evaluator was specifically chosen to represent a unique set of clinical and radiographic experiences. All evaluators were blinded to the subject's identity and clinical history, and they evaluated the images in a unique random order and evaluated each image 3 times separated by a minimum of 7 days. The same computer hardware and software were used. Thirty-nine consecutively assessed, nonsyndromic subjects (ages, 11.5 ± 2.8 years) were evaluated. The CBCT demonstrated excellent sensitivity (88%) and specificity (93%), strong accuracy (ICC, 0.80; 95% CI, ± 0.15), and good reliability, both within observers (ICC, 0.85; 95% CI, ± 0.08) and between observers (ICC, 0.84; 95% CI, ± 0.08). The clinical experience of the CBCT evaluator did not have a statistically significant effect. CBCT is a reliable and accurate tool for identifying adenoid hypertrophy. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  2. Evaluation of the Posterior Superior Alveolar Artery Using Cone Beam Computed Tomography

    PubMed Central

    Pandharbale, Atul A.; Gadgil, Rajeev M.; Bhoosreddy, Ajay R.; Kunte, Varun R.; Ahire, Bhushan S.; Shinde, Manila R.; Joshi, Sidharth S.

    2016-01-01

    Summary Background Maxillary posterior tooth region is an important area with respect to periapical surgery, implant placement, and sinus lifts. Posterior superior alveolar artery (PSAA) is located on the lateral wall of maxillary sinus and may become injured during such surgical procedures. Therefore, knowledge of the subject is essential to a clinician. The goal was to determine the anatomical relationship of posterior superior alveolar artery to the floor of maxillary sinus and alveolar crest. In our study we attempted to present the locations and course of posterior superior alveolar artery (PSAA) using cone beam computed tomography (CBCT) imaging. Material/Methods CBCT scans of 50 patients (30 males, 20 females) who had undergone computed tomography imaging were analyzed. We assessed the visibility and location of vascular canal/notch of posterior superior alveolar artery on cross sectional images and measured the distances from lower margin to the floor of maxillary sinus and alveolar crest in the 1st molar and 2nd molar regions. Unpaired t-test was carried out in the analysis to determine the level of significance. Results Maxillary PSAA was visualized in 36 patients (70%). Mean diameter of the vessel was 0.63 mm. Mean distance between PSAA and alveolar crest was the shortest in the 2nd molar region. The mean distance between PSAA and floor of maxillary sinus was 9.96 mm. Conclusions Periapical surgeries, implants and maxillary sinus lift are performed on routine basis. PSAA is an important structure in the posterior maxillary region; the clinician should be aware of its location and course. CBCT is an excellent tool to localize the PSAA because of it provides finer details at low exposure and less radiation. It should be recommended in clinical practices. PMID:28058075

  3. Radiological Protection in Cone Beam Computed Tomography (CBCT). ICRP Publication 129.

    PubMed

    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

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

    SciTech Connect

    Toporek, Grzegorz Wallach, Daphne Weber, Stefan; Bale, Reto; Widmann, Gerlig

    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.

  5. Is the Schneiderian membrane thickness affected by periodontal disease? A cone beam computed tomography-based extended case series.

    PubMed

    Dagassan-Berndt, Dorothea C; Zitzmann, Nicola U; Lambrecht, J Thomas; Weiger, Roland; Walter, Clemens

    2013-07-01

    The aim was to assess the thickness of Schneiderian membranes (SM) in patients with advanced periodontal disease. 17 dentate patients (DG) scheduled for periodontal surgery on maxillary molars were consecutively recruited and cone beam computed tomographies performed for preoperative diagnosis. Twenty-one patients (EG) requiring cone beam computed tomography-based planning of implant placement in the edentulous posterior maxilla served as controls. Schneiderian membrane thickness measured from cone beam computed tomography was significantly greater in the dentate group compared to the edentulous group, both in the first (p = 0.028) and second (p < 0.001) molar position. In the dentate group, clinical signs of periodontal destruction (increased probing pocket depth or furcation involvement) were not associated with Schneiderian membrane thickness. Additional findings, such as periapical lesions (p = 0.008), and the distance between root tips and maxillary sinus revealed a significant association (p = 0.036) with Schneiderian membrane thickness. In molar regions with periodontal destruction, Schneiderian membrane thickening occurred, particularly in combination with small bone layers above the root tips or periapical lesions.

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

    PubMed Central

    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

  7. Fast computation of statistical uncertainty for spatiotemporal distributions estimated directly from dynamic cone beam SPECT projections

    SciTech Connect

    Reutter, Bryan W.; Gullberg, Grant T.; Huesman, Ronald H.

    2001-04-09

    The estimation of time-activity curves and kinetic model parameters directly from projection data is potentially useful for clinical dynamic single photon emission computed tomography (SPECT) studies, particularly in those clinics that have only single-detector systems and thus are not able to perform rapid tomographic acquisitions. Because the radiopharmaceutical distribution changes while the SPECT gantry rotates, projections at different angles come from different tracer distributions. A dynamic image sequence reconstructed from the inconsistent projections acquired by a slowly rotating gantry can contain artifacts that lead to biases in kinetic parameters estimated from time-activity curves generated by overlaying regions of interest on the images. If cone beam collimators are used and the focal point of the collimators always remains in a particular transaxial plane, additional artifacts can arise in other planes reconstructed using insufficient projection samples [1]. If the projection samples truncate the patient's body, this can result in additional image artifacts. To overcome these sources of bias in conventional image based dynamic data analysis, we and others have been investigating the estimation of time-activity curves and kinetic model parameters directly from dynamic SPECT projection data by modeling the spatial and temporal distribution of the radiopharmaceutical throughout the projected field of view [2-8]. In our previous work we developed a computationally efficient method for fully four-dimensional (4-D) direct estimation of spatiotemporal distributions from dynamic SPECT projection data [5], which extended Formiconi's least squares algorithm for reconstructing temporally static distributions [9]. In addition, we studied the biases that result from modeling various orders temporal continuity and using various time samplings [5]. the present work, we address computational issues associated with evaluating the statistical uncertainty of

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

    PubMed Central

    Srinivasan, Kavitha; Mohammadi, Mohammad; Shepherd, Justin

    2014-01-01

    Summary 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. PMID:25006356

  9. Quality Assessment of Frameless Fractionated Stereotactic Radiotherapy Using Cone Beam Computed Tomography

    SciTech Connect

    Peng, Lee-Cheng; Kahler, Darren; Samant, Sanjiv; Li, Jonathan; Amdur, Robert; Palta, Jatinder R.; Liu, Chihray

    2010-12-01

    Purpose: A quality assessment of intracranial stereotactic radiotherapy was performed using cone beam computed tomography (CBCT). Setup errors were analyzed for two groups of patients: (1) those who were positioned using a frameless SonArray (FSA) system and immobilized with a bite plate and thermoplastic (TP) mask (the bFSA group); and (2) those who were positioned by room laser and immobilized using a TP mask (the mLAS group). Methods and Materials: A quality assurance phantom was used to study the system differences between FSA and CBCT. The quality assessment was performed using an Elekta Synergy imager (XVI) (Elekta Oncology Systems, Norcross, GA) and an On-Board Imager (OBI) (Varian Medical Systems, Palo Alto, CA) for 25 patients. For the first three fractions, and weekly thereafter, the FSA system was used for patient positioning, after which CBCT was performed to obtain setup errors. Results: (1) Phantom tests: The mean differences in the isocenter displacements for the two systems was 1.2 {+-} 0.7 mm. No significant variances were seen between the XVI and OBI units (p{approx}0.208). (2)Patient tests: The mean of the displacements between FSA and CBCT were independent of the CBCT system used; mean setup errors for the bFSA group were smaller (1.2 mm) than those of the mLAS group (3.2 mm) (p < 0.005). For the mLAS patients, the 90th percentile and the maximum rotational displacements were 3{sup o} and 5{sup o}, respectively. A 4-mm drift in setup accuracy occurred over the treatment course for 1 bFSA patient. Conclusions: System differences of less than 1 mm between CBCT and FSA were seen. Error regression was observed for the bFSA patients, using CBCT (up to 4 mm) during the treatment course. For the mLAS group, daily CBCT imaging was needed to obtain acceptable setup accuracies.

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

    SciTech Connect

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

    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.

  11. Relationship of the Gonial Angle and Inferior Alveolar Canal Course Using Cone Beam Computed Tomography

    PubMed Central

    Anbiaee, Najmeh; Bagherpour, Ali

    2015-01-01

    Objectives: Accurate localization of the inferior alveolar canal (IAC) is extremely important in some dental treatments. Anatomical variation of the canal means that it can be difficult to locate. The purpose of this study was to assess the relationship of the gonial angle (GA) size and IAC position using cone beam computed tomography (CBCT). Materials and Methods: In this in vitro study, 61 dry adult human hemi-mandibles were used. The CBCT scans were taken of all samples and GA was measured on all CBCT scans. The samples were divided into two groups of low angle (≤125°) and high angle (>125°). The canal dimensions, length and course were evaluated. On the sagittal view, the IAC path was classified as type A, B or C. On the axial view, canal course was defined as A1 or A2 according to the mental foramen angle. Results: The average GA size was 121.8±7.05° at the right side and 123.8±6.32° at the left side. On the sagittal view, there was a significant correlation between the GA size and the canal course (P=0.04). In the high-angle group, type A was dominant; whereas in the low-angle group, type B was more common. On the axial view of IAC course, type A1 was more common (73.43%). Conclusion: The results showed that GA size was associated with IAC course. In cases with a larger GA, the canal runs in a more straightforward path, and at the same level as the mental foramen. PMID:27252759

  12. Prevalence and location of the posterior superior alveolar artery using cone-beam computed tomography

    PubMed Central

    Tehranchi, Maryam; Shahab, Shahriar; Nouri, Arash

    2017-01-01

    Purpose Insufficient knowledge of the anatomy of the maxillary sinuses prior to sinus graft surgery may lead to perioperative or postoperative complications. This study sought to characterize the position of the posterior superior alveolar artery (PSAA) within the maxillary sinuses using cone-beam computed tomography (CBCT). Materials and Methods A total of 300 patients with edentulous posterior maxillae, including 138 females and 162 males with an age range of 33-86 years, who presented to a radiology clinic between 2013 and 2015 were enrolled in this retrospective cross-sectional study. The distance from the inferior border of the PSAA to the alveolar crest according to the residual ridge classification by Lekholm and Zarb, the distance from the PSAA to the nasal septum and zygomatic arch, and the diameter and position of the PSAA were all assessed on patients' CBCT scans. The data were analyzed using the Mann-Whitney test and the t-test. Results The PSAA was detected on the CBCT scans of 87% of the patients; it was located beneath the sinus membrane in 47% of cases and was intraosseous in 47% of cases. The diameter of the artery was between 1 and 2 mm in most patients (72%). The mean diameter of the artery was 1.29±0.39 mm, and the mean distances from the PSAA to the zygomatic arch, nasal septum, and alveolar crest were 22.59±4.89 mm, 26.51±3.52 mm, and 16.7±3.96 mm, respectively. Conclusion The likelihood of detecting the PSAA on CBCT scans is high; its location is intraosseous or beneath the sinus membrane in most patients. Determining the exact location of the PSAA on CBCT scans preoperatively can help prevent it from being damaged during surgery. PMID:28361028

  13. Study between anb angle and wits appraisal in cone beam computed tomography (cbct)

    PubMed Central

    Cibrián, Rosa; Gandia, Jose L.; Paredes, Vanessa

    2013-01-01

    Objectives: To analyse the ANB and Wits values and to study correlations between those two measurements and other measurements in diagnosing the anteroposterior maxilo-mandibular relationship with CBCT. Study Design: Ninety patients who had previously a CBCT (i-CAT®) as a diagnostic register were selected. A 3D cephalometry was designed using one software package, InVivo5®. This cephalometry included 3 planes of reference, 3 angle measurements and 1 linear measurement. The means and standard deviations of the mean of each measurement were assessed. After that, a Pearson´s correlation coefficient has been performed to analyse the significance of each relationship. Results: When classifying the sample according to the anteroposterior relationship, the values obtained of ANB (Class I: 53%; Class II: 37%; Class III: 10%) and Wits (Class I: 35%; Class II: 56%; Class III: 9%) did not coincide, except for the Class III group. However, of the patients classified differently (Class I and Class II patients) by ANB and Wits, a high percentage of individuals (n=22; 49%), had a mesofacial pattern with a mandibular plane angle within normal values. A correlation has been found between ANB and Wits (r=0,262), occlusal plane angle and ANB (r=0,426), and mandibular plane angle and Wits (r=0,242). No correlation was found between either Wits or ANB in relation with the age of the individuals. Conclusions: ANB and Wits must be included in 3D cephalometric analyses as both are necessary to undertake a more accurate diagnosis of the maxillo-mandibular relationship of the patients. Key words:Cone beam computed tomography, ANB, Wits, cephalometrics. PMID:23722136

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

    PubMed

    Vasconcelos, Taruska Ventorini; Neves, Frederico Sampaio; Moraes, Lívia Almeida Bueno; Freitas, Deborah Queiroz

    2015-01-01

    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.

  15. Motion-aware temporal regularization for improved 4D cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Mory, Cyril; Janssens, Guillaume; Rit, Simon

    2016-09-01

    Four-dimensional cone-beam computed tomography (4D-CBCT) of the free-breathing thorax is a valuable tool in image-guided radiation therapy of the thorax and the upper abdomen. It allows the determination of the position of a tumor throughout the breathing cycle, while only its mean position can be extracted from three-dimensional CBCT. The classical approaches are not fully satisfactory: respiration-correlated methods allow one to accurately locate high-contrast structures in any frame, but contain strong streak artifacts unless the acquisition is significantly slowed down. Motion-compensated methods can yield streak-free, but static, reconstructions. This work proposes a 4D-CBCT method that can be seen as a trade-off between respiration-correlated and motion-compensated reconstruction. It builds upon the existing reconstruction using spatial and temporal regularization (ROOSTER) and is called motion-aware ROOSTER (MA-ROOSTER). It performs temporal regularization along curved trajectories, following the motion estimated on a prior 4D CT scan. MA-ROOSTER does not involve motion-compensated forward and back projections: the input motion is used only during temporal regularization. MA-ROOSTER is compared to ROOSTER, motion-compensated Feldkamp-Davis-Kress (MC-FDK), and two respiration-correlated methods, on CBCT acquisitions of one physical phantom and two patients. It yields streak-free reconstructions, visually similar to MC-FDK, and robust information on tumor location throughout the breathing cycle. MA-ROOSTER also allows a variation of the lung tissue density during the breathing cycle, similar to that of planning CT, which is required for quantitative post-processing.

  16. Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomographic study

    PubMed Central

    Imanimoghaddam, Mahrokh; Madani, Azam Sadat; Mahdavi, Pirooze; Bagherpour, Ali; Darijani, Mansoreh

    2016-01-01

    Purpose This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). Materials and Methods In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. Results The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. Conclusion The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients. PMID:27358820

  17. Cochlear length determination using Cone Beam Computed Tomography in a clinical setting.

    PubMed

    Würfel, Waldemar; Lanfermann, Heinrich; Lenarz, Thomas; Majdani, Omid

    2014-10-01

    Indications for cochlear implants are determined by audiological and medical considerations. Clinical imaging is therefore an integral element for anatomical evaluation in terms of medical considerations. Several authors have discussed the variability of cochlear shape, especially cochlear length. Cochlear length is, however, an increasingly recognized parameter in terms of preoperative evaluation. This study introduces a methodology to determine individual cochlear length in clinical setting by using Cone Beam Computed Tomography. Cochlear length determination was performed retrospectively with an OsiriX curved 3D Multiplanar Reconstruction tool on subjects who underwent temporal bone imaging from January 2011 to February 2013. Cochlear length was defined as the spiral route from the center-distal point of the bony round window along the lateral wall towards the helicotrema, which is the endpoint of the measurement. Cochlear length was measured in 436 temporal bones (218 left ears, 218 right ears, 218 subjects). The mean cochlear length was 37.6 mm (SD: ± 1.93 mm), median was 37.6 mm, range 32-43.5 mm. The cochlear length had a normal distribution. A significant difference was found between cochlear length by gender (p < .0001), but not between the left and right cochlea (p = .301) or according to age. Consideration of the cochlear length in clinical data may be an insufficiently represented parameter in cochlear implant treatment. Literature shows the impact of electrode insertion depth on residual hearing preservation and speech performance. Individual evaluation of the cochlear implant electrode choice may be the next step in personalized cochlear implant treatment as a valuable addition to existing audiological and surgical evaluation. The cochlear length determination methodology presented herein is a reproducible and clinically available parameter. Indeed, revealing a significant cochlear length span width, especially according to gender differences, may be

  18. Binary Decision Trees for Preoperative Periapical Cyst Screening Using Cone-beam Computed Tomography.

    PubMed

    Pitcher, Brandon; Alaqla, Ali; Noujeim, Marcel; Wealleans, James A; Kotsakis, Georgios; Chrepa, Vanessa

    2017-03-01

    Cone-beam computed tomographic (CBCT) analysis allows for 3-dimensional assessment of periradicular lesions and may facilitate preoperative periapical cyst screening. The purpose of this study was to develop and assess the predictive validity of a cyst screening method based on CBCT volumetric analysis alone or combined with designated radiologic criteria. Three independent examiners evaluated 118 presurgical CBCT scans from cases that underwent apicoectomies and had an accompanying gold standard histopathological diagnosis of either a cyst or granuloma. Lesion volume, density, and specific radiologic characteristics were assessed using specialized software. Logistic regression models with histopathological diagnosis as the dependent variable were constructed for cyst prediction, and receiver operating characteristic curves were used to assess the predictive validity of the models. A conditional inference binary decision tree based on a recursive partitioning algorithm was constructed to facilitate preoperative screening. Interobserver agreement was excellent for volume and density, but it varied from poor to good for the radiologic criteria. Volume and root displacement were strong predictors for cyst screening in all analyses. The binary decision tree classifier determined that if the volume of the lesion was >247 mm(3), there was 80% probability of a cyst. If volume was <247 mm(3) and root displacement was present, cyst probability was 60% (78% accuracy). The good accuracy and high specificity of the decision tree classifier renders it a useful preoperative cyst screening tool that can aid in clinical decision making but not a substitute for definitive histopathological diagnosis after biopsy. Confirmatory studies are required to validate the present findings. Published by Elsevier Inc.

  19. Analysis of Prostate Bed Motion Using Daily Cone-Beam Computed Tomography During Postprostatectomy Radiotherapy

    SciTech Connect

    Ost, Piet; De Meerleer, Gert; De Gersem, Werner; Impens, Aline; De Neve, Wilfried

    2011-01-01

    Purpose: To report on the interfraction total positioning error of the postoperative prostate bed and to quantify its components (bony misalignment [BM]and prostate bed motion [PBM]) using daily kilovoltage cone-beam computed tomography (CBCT). The role of an adaptive radiotherapy schedule (ART) was investigated. Methods and Materials: A total of 547 daily CBCT images from 15 consecutive patients who had been treated with prostate bed radiotherapy were retrospectively analyzed. The positioning error was measured by rigid co-registration of the daily CBCT with pretreatment CT planning scan. The total positioning error was quantified by co-registration of the CBCT with the CT planning scan to match the anterior rectal wall. Automatic bony pelvis co-registration was performed to separate BM and PBM. The ART was determined by the average total positioning error from the first 5 CBCT images. Results: The systematic error for the total positioning error in the left-right, superoinferior, and anteroposterior direction was 2.69, 2.00, and 2.65 mm with a random error of 1.99, 1.49, and 2.25 mm, resulting in a planning target volume margin of 8, 6, and 8 mm, respectively. ART reduced the margin by 54%, 44%, and 40%, respectively. Systematic errors in the left-right, superoinferior, and anteroposterior direction for BM was 2.66, 1.83, and 2.60 mm and for PBM was 0.44, 0.92, and 2.50 mm with a random error of 1.88, 1.24, and 1.77 mm for BM and 0.99, 1.38, and 2.32 mm for PBM, respectively. Conclusion: Without treatment verifications, 6-8-mm planning target volume margins are required because of PBM and BM. The anteroposterior PBM was significant. An ART protocol can reduce these planning target volume margins.

  20. Validating cone-beam computed tomography for peri-implant bone morphometric analysis

    PubMed Central

    Huang, Yan; Dessel, Jeroen Van; Depypere, Maarten; EzEldeen, Mostafa; Iliescu, Alexandru Andrei; Santos, Emanuela Dos; Lambrichts, Ivo; Liang, Xin; Jacobs, Reinhilde

    2014-01-01

    Cone-beam computed tomography (CBCT) has been recently used to analyse trabecular bone structure around dental implants. To validate the use of CBCT for three-dimensional (3D) peri-implant trabecular bone morphometry by comparing it to two-dimensional (2D) histology, 36 alveolar bone samples (with implants n=27 vs. without implants n=9) from six mongrel dogs, were scanned ex vivo using a high-resolution (80 µm) CBCT. After scanning, all samples were decalcified and then sectioned into thin histological sections (∼6 μm) to obtain high contrast 2D images. By using CTAn imaging software, bone morphometric parameters including trabecular number (Tb.N), thickness (Tb.Th), separation (Tb.Sp) and bone volume fraction (BV/TV) were examined on both CBCT and corresponding histological images. Higher Tb.Th and Tb.Sp, lower BV/TV and Tb.N were found on CBCT images (P<0.001). Both measurements on the peri-implant trabecular bone structure showed moderate to high correlation (r=0.65–0.85). The Bland–Altman plots showed strongest agreement for Tb.Th followed by Tb.Sp, Tb.N and BV/TV, regardless of the presence of implants. The current findings support the assumption that peri-implant trabecular bone structures based on high-resolution CBCT measurements are representative for the underlying histological bone characteristics, indicating a potential clinical diagnostic use of CBCT-based peri-implant bone morphometric characterisation. PMID:26273522

  1. Evaluation of Morphology and Anatomical Measurement of Nasopalatine Canal Using Cone Beam Computed Tomography

    PubMed Central

    Panjnoush, Mehrdad; Norouzi, Hamideh; Kheirandish, Yasaman; Shamshiri, Ahmad Reza; Mofidi, Niloufar

    2016-01-01

    Objectives: Precise radiographic assessment of the nasopalatine canal is required to prevent implant failure. The purpose of the current study was to determine the three dimensional (3D) morphology, as well as the dimensions of the nasopalatine canal using cone beam computed tomography (CBCT). Materials and Methods: In this descriptive cross-sectional study, maxillary CBCT images from 300 patients (150 men, 150 women) were retrospectively evaluated. Sagittal and coronal views were reviewed to determine the nasopalatine canal morphology and dimensions. The difference in canal dimensions between men and women was evaluated using the Student’s t-test while the difference in canal morphology between the two sexes was assessed using Chi-square test. Results: A total of 199 (66.3%) patients had type A canal (cylindrical without a branch), 69 (23%) had type B canal (a canal with a branch in the upper part), and 32 (10.7 %) had type C canal (a canal with a branch in the middle part). Incisive foramen diameter was 4.7±1.11mm on the sagittal section. Alveolar bone width in the anterior part of the canal was 12.3±1.7mm in the upper one third, 10.7±1.7mm in the middle one third, and 9.8±1.4mm in the lower one third. The angle of canal with palate was 109.5±5.7°. On the coronal sections, canal length was 14.1±3.0mm, incisive foramen diameter was 4.6±1.0mm, and canal diameter in the nasal floor was 5.1±1.0mm. Conclusions: Significant differences in canal morphology were observed among the patients and CBCT was useful in determining nasopalatine canal morphology and its dimensions before implant placement. PMID:28127321

  2. A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation

    PubMed Central

    Ma, Yue; Han, Ting; Chen, Xinyu; Wan, Fang; Lu, Yating; Yan, Songhe; Wang, Yan

    2015-01-01

    The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice–disto-lingual canal orifice–mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation. PMID:26241480

  3. Motion-aware temporal regularization for improved 4D cone-beam computed tomography.

    PubMed

    Mory, Cyril; Janssens, Guillaume; Rit, Simon

    2016-09-21

    Four-dimensional cone-beam computed tomography (4D-CBCT) of the free-breathing thorax is a valuable tool in image-guided radiation therapy of the thorax and the upper abdomen. It allows the determination of the position of a tumor throughout the breathing cycle, while only its mean position can be extracted from three-dimensional CBCT. The classical approaches are not fully satisfactory: respiration-correlated methods allow one to accurately locate high-contrast structures in any frame, but contain strong streak artifacts unless the acquisition is significantly slowed down. Motion-compensated methods can yield streak-free, but static, reconstructions. This work proposes a 4D-CBCT method that can be seen as a trade-off between respiration-correlated and motion-compensated reconstruction. It builds upon the existing reconstruction using spatial and temporal regularization (ROOSTER) and is called motion-aware ROOSTER (MA-ROOSTER). It performs temporal regularization along curved trajectories, following the motion estimated on a prior 4D CT scan. MA-ROOSTER does not involve motion-compensated forward and back projections: the input motion is used only during temporal regularization. MA-ROOSTER is compared to ROOSTER, motion-compensated Feldkamp-Davis-Kress (MC-FDK), and two respiration-correlated methods, on CBCT acquisitions of one physical phantom and two patients. It yields streak-free reconstructions, visually similar to MC-FDK, and robust information on tumor location throughout the breathing cycle. MA-ROOSTER also allows a variation of the lung tissue density during the breathing cycle, similar to that of planning CT, which is required for quantitative post-processing.

  4. Measurement of skin dose from cone-beam computed tomography imaging

    PubMed Central

    2013-01-01

    Objective To measure surface skin dose from various cone-beam computed tomography (CBCT) scanners using point-dosimeters. Materials & methods A head anthropomorphic phantom was used with nanoDOT optically stimulated luminescence (OSL) dosimeters (Landauer Corp., Glenwood, IL) attached to various anatomic landmarks. The phantom was scanned using multiple exposure protocols for craniofacial evaluations in three different CBCT units and a conventional x-ray imaging system. The dosimeters were calibrated for each of the scan protocols on the different imaging systems. Peak skin dose and surface doses at the eye lens, thyroid, submandibular and parotid gland levels were measured. Results The measured skin doses ranged from 0.09 to 4.62 mGy depending on dosimeter positions and imaging systems. The average surface doses to the lens locations were ~4.0 mGy, well below the threshold for cataractogenesis (500 mGy). The results changed accordingly with x-ray tube output (mAs and kV) and also were sensitive to scan field of view (SFOV). As compared to the conventional panoramic and cephalometric imaging system, doses from all three CBCT systems were at least an order of magnitude higher. Conclusions Peak skin dose and surface doses at the eye lens, thyroid, and salivary gland levels measured from the CBCT imaging systems were lower than the thresholds to induce deterministic effects. However, our findings do not justify the routine use of CBCT imaging in orthodontics considering the lifetime-attributable risk to the individual. PMID:24192155

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

    PubMed Central

    Al Haffar, Iyad; Khattab, Razan

    2014-01-01

    Purpose 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. Materials and Methods 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 cm×15 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. Results 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. Conclusion 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. PMID:25473633

  6. Cone Beam Computed Tomography- An Effective Tool in Detecting Caries Under Fixed Dental Prostheses

    PubMed Central

    Gondivkar, Shailesh Madhukar; Bhoosreddy, Ajay Ramesh; Shah, Karan Rajendra; Verma, Gaurav Ravishankar; Mehrotra, Gayatri Praveen; Nerkar, Ashwini Chandrakant

    2016-01-01

    Introduction Caries under restorations is the most common reason for re-treatment and replacement in restorative failures. To avoid failures of fixed dental prostheses, it is important to diagnose caries under it earlier. Without image degradation and metal artifacts, Cone Beam Computed Tomography (CBCT) can be the solution to detect caries without removing fixed dental prostheses. Aim The aim of this study was to determine the efficacy of CBCT in detecting caries under fixed dental prostheses. Materials and Methods Each specimen was scanned with CBCT for evaluation of secondary caries under fixed prostheses. Exposure parameters were 60 kVp and 3mA. Field of View (FOV) used was 8cm X 8cm. According to International Caries Detection and Assessment System (ICDAS) criteria, six Grade 6 carious extracted teeth were selected. All teeth were prepared with four different specimens - full metal, metal-ceramic, full ceramic and metal-acrylic crowns for each tooth. Each specimen was scanned by CBCT. T-test was performed for mean gray value differences between caries and noncaries regions of each material. Gray values were recorded and evaluated for different parameters using two-way analysis of variance. Results Significant differences were found with respect to material (full metal, metal-ceramic, full ceramic and metal-acrylic) and situation (caries/noncaries) (p<0.001). There were no significant differences with respect to location (anterior or posterior). Mean gray values of caries and noncaries regions were found to be different for each material. Conclusion CBCT can be used as a post-treatment diagnostic technique for detecting caries under fixed prostheses without removing it. PMID:27656548

  7. [Quantitative assessment on artifacts of dental restorative materials in cone beam computed tomography].

    PubMed

    Yuan, Fu-song; Sun, Yu-chun; Xie, Xiao-yan; Wang, Yong; Lv, Pei-jun

    2013-12-18

    To quantitatively evaluate the artifacts appearance of eight kinds of common dental restorative materials, such as zirconia. For the full-crown tooth preparation of mandibular first molar, eight kinds of full-crowns, such as zirconia all-ceramic crown, glass ceramic crown, ceramage crown, Au-Pt based porcelain-fused-metal (PFM) crown, Pure Titanium PFM crown, Co-Cr PFM crown, Ni-Cr PFM crown, and Au-Pd metal crown were fabricated. And natural teeth in vitro were used as controls. These full-crown and natural teeth in vitro were mounted an ultraviolet-curable resin fixed plate. High resolution cone beam computed tomography (CBCT) was used to scan all of the crowns and natural teeth in vitro, and their DICOM data were imported into software MIMICS 10.0. Then, the number of stripes and the maximum diameters of artifacts around the full-crowns were evaluated quantitatively in two-dimensional tomography images. In the two-dimensional tomography images,the artifacts did not appear around the natural teeth in vitro, glass ceramic crown, and ceramage crown. But thr artifacts appeared around the zirconia all-ceramic and metal crown. The number of stripes of artifacts was five to nine per one crown. The maximum diameters of the artifacts were 2.4 to 2.6 cm and 2.2 to 2.7 cm. In the two-dimensional tomography images of CBCT, stripe-like and radical artifacts were caused around the zirconia all-ceramic crown and metal based porcelain-fused-metal crowns. These artifacts could lower the imaging quality of the full crown shape greatly. The artifact was not caused around the natural teeth in vitro, glass ceramic crown, and ceramage crown.

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

    PubMed Central

    Rashsuren, Oyuntugs; Choi, Jin-Woo; Han, Won-Jeong

    2014-01-01

    Purpose To investigate the prevalence of bifid and trifid mandibular canals using cone-beam computed tomography (CBCT) images, and to measure their length, diameter, and angle. Materials and Methods CBCT images of 500 patients, involving 755 hemi-mandibles, were used for this study. The presence and type of bifid mandibular canal was evaluated according to a modified classification of Naitoh et al. Prevalence rates were determined according to age group, gender, and type. Further, their 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. Results 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°, and the mean inferior angle was 37.7°. Conclusion 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. PMID:25279344

  9. Detection and characterization of the accessory mental foramen using cone-beam computed tomography.

    PubMed

    Li, Yihan; Yang, Xiangwen; Zhang, Bichu; Wei, Bin; Gong, Yao

    2017-09-28

    This study aimed to investigate the frequency and characteristics of accessory mental foramina (AMFs) and their bony canals in a selected Chinese population using cone-beam computed tomography (CBCT). Reconstructed CBCT images of the mandible in 784 Chinese patients (305 males and 479 females) were retrospectively analysed to identify the AMF. The presence, dimension and location of the AMF as well as the origin and course of the associated bony canal were evaluated and classified. Variations in these characteristics were analysed according to gender, side and age. A total of 66 AMFs were found in 57 (7.3%) of the 784 patients. The frequency of AMFs was significantly influenced by gender and side of the mandible (p < .05). Most AMFs were located apically between apices of the first and second premolars. The high-position AMFs (above the mental foramen) accounted for 54.5% of the total. The mean horizontal and vertical diameters of the AMF were 1.38 ± 0.47 and 1.23 ± 0.37 mm, respectively. Two typical types of the bony canal leading to the AMF were identified according to their bifurcation site from the mandibular canal. Most bony canals originated from the anterior loop of the mental canal (56.1%) and coursed posterosuperiorly (36.3%). The mean length of the bony canals was 5.78 ± 2.31 mm. This study presents a considerable frequency of AMFs in a Chinese population. The high-position AMF and the associated bony canal coursing in the oblique upward direction appear frequently. Thus, clinicians should be alert to the presence of the AMF to avoid neurovascular complications especially when dental procedures require periosteum detachment and implant insertion in the mental region.

  10. Quality and accuracy of cone beam computed tomography gated by active breathing control

    SciTech Connect

    Thompson, Bria P.; Hugo, Geoffrey D.

    2008-12-15

    The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breathing), and free breathing respiration correlated CBCT. Image quality was assessed in phantom. Accuracy of reconstructed voxel intensity, uniformity, and root mean square error were evaluated. Registration accuracy (bony and soft tissue) was quantified with both an anthropomorphic and a quality assurance phantom. Gantry angle accuracy was measured with respect to gantry speed modulation. Conventional ABC-CBCT scan time ranged from 2.3 to 5.8 min. Fast ABC-CBCT scan time ranged from 1.4 to 1.8 min, and respiratory correlated CBCT scans took 2.1 min to complete. Voxel intensity value for ABC gated scans was accurate relative to a normal clinical scan with all projections. Uniformity and root mean square error performance degraded as the number of projections used in the reconstruction of the fast ABC-CBCT scans decreased (shortest breath hold, longest free breathing segment). Registration accuracy for small, large, and rotational corrections was within 1 mm and 1 degree sign . Gantry angle accuracy was within 1 degree sign for all scans. For high-contrast targets, performance for image-guidance purposes was similar for fast and conventional ABC-CBCT scans and respiration correlated CBCT.

  11. Quality and accuracy of cone beam computed tomography gated by active breathing control.

    PubMed

    Thompson, Bria P; Hugo, Geoffrey D

    2008-12-01

    The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breathing), and free breathing respiration correlated CBCT. Image quality was assessed in phantom. Accuracy of reconstructed voxel intensity, uniformity, and root mean square error were evaluated. Registration accuracy (bony and soft tissue) was quantified with both an anthropomorphic and a quality assurance phantom. Gantry angle accuracy was measured with respect to gantry speed modulation. Conventional ABC-CBCT scan time ranged from 2.3 to 5.8 min. Fast ABC-CBCT scan time ranged from 1.4 to 1.8 min, and respiratory correlated CBCT scans took 2.1 min to complete. Voxel intensity value for ABC gated scans was accurate relative to a normal clinical scan with all projections. Uniformity and root mean square error performance degraded as the number of projections used in the reconstruction of the fast ABC-CBCT scans decreased (shortest breath hold, longest free breathing segment). Registration accuracy for small, large, and rotational corrections was within 1 mm and 1 degrees. Gantry angle accuracy was within 1 degrees for all scans. For high-contrast targets, performance for image-guidance purposes was similar for fast and conventional ABC-CBCT scans and respiration correlated CBCT.

  12. Condylar Erosion in Patients With Chronic Temporomandibular Joint Arthralgia: A Cone-Beam Computed Tomography Study.

    PubMed

    Emshoff, Rüdiger; Bertram, Felix; Schnabl, Dagmar; Stigler, Robert; Steinmaßl, Otto; Rudisch, Ansgar

    2016-07-01

    The objective of this study was to assess the association between temporomandibular joint (TMJ) condylar erosion and chronic TMJ arthralgia. Based on a sample size estimation, this case-and-control study involved 198 patients 16 to 73 years old recruited from a routine clinical practice (99 cases, patients with chronic TMJ arthralgia and mean pain duration of 16.4 months; 99 controls, asymptomatic patients without a history of orofacial pain). The clinical diagnosis of arthralgia was made according to the Research Diagnostic Criteria for Temporomandibular Disorders. Cone-beam computed tomographic (CBCT) images were evaluated for the presence or absence of erosive osseous changes of the TMJ condyle. Severity of TMJ condylar erosion was classified as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion). Logistic regression analysis was used to assess the association between chronic TMJ arthralgia and condylar erosion, adjusting for age, gender, number of missing posterior teeth, and number of dental quadrants with missing posterior teeth. TMJ condylar erosion was found in 59.6% of cases and 21.2% of controls. There was a significant association between TMJ arthralgia and degree of condylar erosion (P < .001). The odds ratio that a TMJ with condylar erosion grade II might belong to the TMJ arthralgia group was strong (3.1:1; 95% confidence interval [CI], 1.17 to 8.09) and significant (P = .023). Significant increases in risk of TMJ arthralgia occurred with condylar erosion grade III (7.7:1; 95% CI, 3.09 to 19.18; P < .001). The study provides evidence of an association between TMJ condylar erosion and chronic TMJ arthralgia. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  13. Automated patient setup and gating using cone beam computed tomography projections

    NASA Astrophysics Data System (ADS)

    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  <  0.01) compared to the manual setup using kV fluoroscopy. For non-gated patients from Institution B (6 patients, 16 fractions), the 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.

  14. Knowledge and attitudes of Turkish endodontists towards digital radiology and cone beam computed tomography.

    PubMed

    Yalcinkaya, S Ercalik; Berker, Y Garip; Peker, S; Basturk, F B

    2014-01-01

    The aim of this study was to assess the knowledge and attitudes of Turkish endodontists toward digital radiological imaging (DRI) and cone-beam computed tomography (CBCT). One hundred and fifty questionnaires were distributed. Questionnaires were given to a sample of endodontists and PhD students in endodontics who attended the 11 th International Congress of the Turkish Endodontic Society in Istanbul in 2012. Following the congress, the same questionnaires were sent electronically to endodontists who did not attend the congress. The participants were asked to answer 28 multiple-choice questions concerning their knowledge and practice regarding recent imaging techniques. The questions were subdivided into 2 main topics; general information; general approach to digital imaging. The statistical analysis was carried out by an χ2-test to compare the means at a significance level of P < 0.05. The response rate for this study was 74%. The mean age of the endodontists who participated in this study was 32.74 ± 10.40 (range 22-61 years). Of the endodontists, 76.6% used digital imaging techniques (DUEs) in their clinics. Statistically significant differences were found between the DUEs and endodontists not using digital imaging (NDUEs), regarding age, gender, graduation year and place of employment ( P < 0.01). Endodontists 40-years-old and above had significantly lower knowledge of CBCT compared to the younger groups ( P = 0.001). The number of endodontists using digital imaging has been increasing in Turkey. The findings of the present study highlighted the need for adapting to new technologies via continuing education.

  15. Incidental findings from a retrospective study of 318 cone beam computed tomography consultation reports.

    PubMed

    Pette, Gregory A; Norkin, Frederic J; Ganeles, Jeffrey; Hardigan, Patrick; Lask, Enrique; Zfaz, Samuel; Parker, William

    2012-01-01

    Cone beam computed tomography (CBCT) is a three-dimensional radiographic technique used in planning implant therapy to help clinicians determine the volume and dimension of bone available for implant placement, and CBCT images potentially depict coincident findings. Three hundred eighteen patients received CBCT scans prior to receiving implants, which were interpreted by blinded board-certified oral and maxillofacial radiologists. All incidental findings were defined as non-tooth-related pathologies or abnormalities. These findings were categorized and analyzed using descriptive statistics. The patients ranged in age from 16 to 91 years (mean age for men, 64.73 ± 15.05 years; for women, 62.47 ± 15.83 years). Controlling for age, men were 2.13 times more likely to have sinus pathology than women. Patients over age 65 were 5.01 times more likely to demonstrate vascular pathology (eg, carotid artery calcification) than patients ages 41 to 65; the likelihood versus patients ages 16 to 40 was 13.39. Women were 2.63 times more likely to display brain pathology (eg, pineal or pituitary calcifications). Controlling for gender, patients ages 41 to 65 were 3.17 times more likely to exhibit condylar pathology (eg, degenerative changes) than patients ages 16 to 40. Similarly, patients above age 65 were 3.53 times more likely to show condylar pathology than patients ages 16 to 40, and women were 1.61 times more likely to have condylar pathology than men. Versus patients ages 16 to 40, patients ages 41 to 65 were 17.69 times more likely to show signs of vertebral pathology (eg, degenerative disc changes) and patients over age 65 were 28.67 times more likely to display vertebral pathology. CBCT scans frequently reveal non-tooth-related pathologies and/or abnormalities in the head and neck region. Therefore, comprehensive review of the entire CBCT image set is necessary.

  16. Validity of ridge mapping and cone beam computed tomography in dental implant therapy

    PubMed Central

    Castro-Ruiz, Carmen Teresa; Noriega, Jorge; Guerrero, Maria Eugenia

    2015-01-01

    Aim: The purpose of this study was to compare the validity of alveolar ridge measurements obtained with ridge mapping (RM) technique against cone beam computed tomography (CBCT) measurements. Materials and Methods: Twenty partially edentulous patients were recruited for implant placement in the Clinic of San Martin de Porres University. For all the measurements, a vacuum-formed stent was fabricated for each subject. A buccal and lingual point was made in the stent to provide a reference of measurement for each implant site. RM measurements with the stent were obtained before and after surgical flap reflection. Two calibrated observers made the CBCT images measurements. T-test was used for the statistical analysis. Values <0.05 were considered statistically significant. Also, specificity and sensibility of CBCT and RM were compared. Intra-class correlation coefficient (ICC)_ was measure between CBCT measurements. Results: A total of 62 implants sites were evaluated. No statistical significant differences were obtained with CBCT and RM measurements (P = 0,207). Detecting proper buccal-lingual ridge, the sensitivity and specificity were 59% and 91% for RM while CBCT obtained 92% of sensitivity and 94% of specificity. Concordance was found “good” (ICC 0.82). Conclusion: Both methods provide valid measurements. Even though, we found diagnostic limitations in the RM, it demonstrated to be a useful method for its exactitude, low cost, the immediate result and no need of radiation. CBCT was recommended when the bone ridge width and height were in the less than ideal for conventional dental implant placement. PMID:26229269

  17. Cone beam computed tomography analysis of dentoalveolar changes immediately after maxillary expansion

    PubMed Central

    Domann, Carin Elizabeth; Kau, Chung How; English, Jeryl D.; Xia, James J.; Souccar, Nada M.; Lee, Robert P.

    2015-01-01

    Aim Rapid maxillary expansion (RME) splits the midpalatal suture to correct maxillary transverse discrepancies and increase the arch perimeter. The goal of this paper is to evaluate the immediate effects of RME with Hyrax appliances on the dentoalveolar complex using cone beam computed tomography (CBCT). Methods Twenty-eight patients (19 females and 9 males) requiring maxillary expansion therapy were included (mean age, 14.1 years; range, 13 to 20 years). CBCT images were taken at T1 (before maxillary expansion) and T2 (immediately after expansion) as part of clinical records. Maxillary arch width, posterior segment angulation, and buccal bone thickness at the level of the first premolar and first molar were evaluated. Paired t tests determined statistical significance (P < .05). Results The mean ± SD amount of expansion achieved was 4.7788 ± 2.8474 mm for the maxillary premolars and 4.6943 ± 3.2198 mm for the molars. Significant tipping of the palatal roots of the maxillary right and left premolars as well as that for the maxillary left molar was observed. When present, the thickness of the buccal plate decreased on all observed roots. Conclusion There is a significant increase in interpremolar and intermolar distance with RME. The increase in root angulation suggests that the movement is more tipping than translation. The thickness of the buccal plate decreases immediately after RME. Therefore, the level of inflammation should be closely monitored to avoid periodontal destruction. There is a need to define standardized reference planes and comparable methodology to achieve compatible results among studies. PMID:22022691

  18. Radiation dose of cone-beam computed tomography compared to conventional radiographs in orthodontics.

    PubMed

    Signorelli, Luca; Patcas, Raphael; Peltomäki, Timo; Schätzle, Marc

    2016-01-01

    The aim of this study was to determine radiation doses of different cone-beam computed tomography (CBCT) scan modes in comparison to a conventional set of orthodontic radiographs (COR) by means of phantom dosimetry. Thermoluminescent dosimeter (TLD) chips (3 × 1 × 1 mm) were used on an adult male tissue-equivalent phantom to record the distribution of the absorbed radiation dose. Three different scanning modes (i.e., portrait, normal landscape, and fast scan landscape) were compared to CORs [i.e., conventional lateral (LC) and posteroanterior (PA) cephalograms and digital panoramic radiograph (OPG)]. The following radiation levels were measured: 131.7, 91, and 77 μSv in the portrait, normal landscape, and fast landscape modes, respectively. The overall effective dose for a COR was 35.81 μSv (PA: 8.90 μSv; OPG: 21.87 μSv; LC: 5.03 μSv). Although one CBCT scan may replace all CORs, one set of CORs still entails 2-4 times less radiation than one CBCT. Depending on the scan mode, the radiation dose of a CBCT is about 3-6 times an OPG, 8-14 times a PA, and 15-26 times a lateral LC. Finally, in order to fully reconstruct cephalograms including the cranial base and other important structures, the CBCT portrait mode must be chosen, rendering the difference in radiation exposure even clearer (131.7 vs. 35.81 μSv). Shielding radiation-sensitive organs can reduce the effective dose considerably. CBCT should not be recommended for use in all orthodontic patients as a substitute for a conventional set of radiographs. In CBCT, reducing the height of the field of view and shielding the thyroid are advisable methods and must be implemented to lower the exposure dose.

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

    PubMed

    van Vlijmen, Olivier J C; Kuijpers, Mette A R; Bergé, Stefaan J; Schols, Jan G J H; Maal, Thomas J J; Breuning, Hero; Kuijpers-Jagtman, Anne Marie

    2012-03-01

    The authors conducted a systematic review of cone-beam computed tomography (CBCT) applications in orthodontics and evaluated the level of evidence to determine whether the use of CBCT is justified in orthodontics. The authors identified articles by searching the Cochrane Library, PubMed, MEDLINE, Embase, Scopus and Cumulative Index to Nursing and Allied Health Literature databases. They searched the articles' reference lists manually for additional articles and had no language limitations. They did not search the gray literature. Inclusion criteria were CBCT use in orthodontics and that the participants be human. The lowest level of evidence accepted for inclusion was a case series with five or more participants. The authors evaluated the studies' methodological quality according to 13 criteria related to study design, measurements and statistical analysis. The authors identified 550 articles, and 50 met the inclusion criteria. Study topics included temporary anchorage devices, cephalometry, combined orthodontic and surgical treatment, airway measurements, root resorption and tooth impactions, and cleft lip and palate. The methodological quality averaged 53 percent (range, 15-77 percent) of the maximum score. The authors found no high-quality evidence regarding the benefits of CBCT use in orthodontics. Limited evidence shows that CBCT offers better diagnostic potential, leads to better treatment planning or results in better treatment outcome than do conventional imaging modalities. Only the results of studies on airway diagnostics provided sound scientific data suggesting that CBCT use has added value. The additional radiation exposure should be weighed against possible benefits of CBCT, which have not been supported in the literature. In future studies, investigators should evaluate the effects of CBCT on treatment procedures, progression and outcome quantitatively.

  20. Assessment of the appearance, location and morphology of mandibular lingual foramina using cone beam computed tomography.

    PubMed

    He, Xuejiao; Jiang, Junqiang; Cai, Wei; Pan, Yun; Yang, Yang; Zhu, Ke; Zheng, Yun

    2016-10-01

    To investigate the appearance, location and morphology of mandibular lingual foramina (MLF) in the Chinese Han population using cone beam computed tomography (CBCT). CBCT images of the mandibular body in 200 patients (103 female patients and 97 male patients, age range 10-70 years) were retrospectively analysed to identify MLF. The canal number, location and direction were assessed. Additionally, the diameter of the lingual foramen, the distance between the alveolar crest and the lingual foramen, the distance between the tooth apex and the lingual foramen and the distance from the mandibular border to the lingual foramen were examined to describe the MLF characteristics. Gender and age differences with respect to foramina were also studied. CBCT can be utilized to visualise lingual foramina. In this study, 683 lingual foramina were detected in 200 CBCT scans, with 538 (78.77%) being ≤1 mm in diameter and 145 (21.23%) being >1 mm. In total, 85.07% of MLF are median lingual canals (MLC) and 14.93% are lateral lingual canals (LLC). Two typical types of lingual foramina were identified according to their relationship with the tooth apex. Most lingual foramina (74.08%) were found below the tooth apex, and those above the tooth apex were much smaller in diameter. Male patients had statistically larger lingual foramina. The distance between the lingual foramen and the tooth apex changed with increasing age. Determination of the presence, position and size of lingual foramina is important before performing a surgical procedure. Careful implant-prosthetic treatment planning is particularly important in male and/or elderly patients because of the structural characteristics of their lingual foramina. © 2016 FDI World Dental Federation.

  1. Cone-Beam Computed Tomography (CBCT) Versus CT in Lung Ablation Procedure: Which is Faster?

    SciTech Connect

    Cazzato, Roberto Luigi Battistuzzi, Jean-Benoit Catena, Vittorio; Grasso, Rosario Francesco Zobel, Bruno Beomonte; Schena, Emiliano; Buy, Xavier Palussiere, Jean

    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.

  2. Influence of Cone-Beam Computed Tomography filters on diagnosis of simulated endodontic complications.

    PubMed

    Verner, F S; D'Addazio, P S; Campos, C N; Devito, K L; Almeida, S M; Junqueira, R B

    2017-11-01

    To evaluate the influence of cone-beam computed tomography (CBCT) filters on diagnosis of simulated endodontic complications. Sixteen human teeth, in three mandibles, were submitted to the following simulated endodontic complications: (G1) fractured file, (G2) perforations in the canal walls, (G3) deviated cast post, and (G4) external root resorption. The mandibles were submitted to CBCT examination (I-Cat(®) Next Generation). Five oral radiologists evaluated the images independently with and without XoranCat(®) software filters. Accuracy, sensitivity and specificity were determined. ROC curves were calculated for each group with the filters, and the areas under the curves were compared using anova (one-way) test. McNemar test was applied for pair-wise agreement between all images versus the gold standard and original images versus images with filters (P < 0.05). G1 was the most difficult endodontic complication to diagnosis, followed by G2, G4 and G3. There were no differences between areas under the ROC curves for the filters in all groups; however, Sharpen Super Mild filter had the best results for G1 (0.47), Angio Sharpen Low 3 × 3 for G2 (0.93), Angio Sharpen Low 3 × 3, S9, Shadow and Sharpen for G3 (1.00) and Sharpen 3 × 3 for G4 (1.00). The McNemar test revealed significant differences between all filters with the gold standard (P = 0.00 for all filters) and the originals images (P = 0.00 for all filters) only in G1 group. There were no differences in the other groups. The filters did not improve the diagnosis of the simulated endodontic complications evaluated. Their diagnosis remains a major challenge in clinical practice. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  3. Predictive factors of the dimensions and location of mental foramen using cone beam computed tomography

    PubMed Central

    Fernández-Alonso, Ana; Smyth-Chamosa, Ernesto; Suárez-Quintanilla, Juan Antonio; Varela-Mallou, Jesús

    2017-01-01

    Objective The mental foramen (MF) hosts main neurovascular structures, making it of crucial importance for surgical procedures. This study aimed to analyze the factors influencing the dimensions and location of the MF. Materials and methods Cone beam computed tomography (CBCT) scans of 344 patients were examined for MF dimensions, as well as for the distances from the MF to the alveolar crest (MF-MSB), and to the inferior mandibular border (MF-MIB). Results Gender, mandibular side and presence of accessory mental foramina (AMF) significantly influence MF area. Males, left hemimandibles, and hemimandibles with no AMF had a higher rate of large MF areas (B = − 0.60; p = 0.003, females; B = 0.55; p = 0.005; B = 0.85; p = 0.038). Age, gender and dental status significantly influence MF-MSB distance. The distance decreased as age increased (B = −0.054; p = 0.001), females showed a lower rate of long MF-MSB distances (B = −0.94, p = 0.001), and dentate patients showed a higher rate of long MF-MSB distances (B = 2.27; p = 0.001). Age, gender and emerging angle significantly influenced MF-MIB distance. The distance decreased as age and emerging angle increased (B = −0.01; p = 0.001; B = −0.03; p = 0.001), and females had a lower rate of long MF-MIB distances (B = −1.94, p = 0.001). Conclusions General and local factors influence the dimensions and location of MF. MF dimensions are influenced by gender, mandibular side, anteroposterior position, and the presence of AMF. Distance from MF to alveolar crest is influenced by gender, age and dental status, while the relative MF position is influenced by age and dental status. CBCT images make it possible to analyze the MF in order to avoid complications during surgical procedures. PMID:28817595

  4. Sphenoid bone changes in rapid maxillary expansion assessed with cone-beam computed tomography

    PubMed Central

    Stepanko, Lucas S.

    2016-01-01

    Objective Rapid maxillary expansion (RME) is used to expand the maxilla and increase arch perimeter; yet, there are few reports on its effects on the sphenoid bone. With cone-beam computed topography (CBCT), it is possible to visualize sphenoid bone changes. The purpose of this study was to investigate sphenoid bone changes observed in conjunction with RME treatments, using CBCT. Methods Sixty patients (34 women and 26 men, aged 11–17 years) underwent RME as part of their orthodontic treatment. Patients were randomly assigned to one of three groups: a tooth-anchored group, a bone-anchored group, or a control group. Initial CBCT scans were performed preceding the RME treatment (T1) and again directly after the completion of expansion (T2). Statistical analysis included ANOVA, descriptive statistics, and the intraclass correlation coefficient (ICC). Results The reliability of the landmark location was at least 0.783, and the largest ICC mean measurement error was 2.32 mm. With regard to distances, the largest change was 0.78 mm, which was not statistically significant (p > 0.05). Statistical significance was established in patient groups of the same sex and treatment type for the following distance measurements: right anterior lateral pterygoid plate to the right edge of the hypophyseal fossa (d2), anterior distance between the medial pterygoid plates (d4), and anterior distance between the left medial and lateral plates (d8). Conclusions In this study, there were no clinically significant changes in the sphenoid bone due to RME treatments regardless of sex or treatment type. PMID:27668190

  5. Cone Beam Computed Tomography Number Errors and Consequences for Radiotherapy Planning: An Investigation of Correction Methods

    SciTech Connect

    Poludniowski, Gavin G.; Evans, Philip M.; Webb, Steve

    2012-09-01

    Purpose: The potential of keV cone beam computed tomography (CBCT) for guiding adaptive replanning is well-known. There are impediments to this, one being CBCT number accuracy. The purpose of this study was to investigate CBCT number correction methods and the affect of residual inaccuracies on dose deposition. Four different correction strategies were applied to the same patient data to compare performance and the sophistication of correction-method needed for acceptable dose errors. Methods and Materials: Planning CT and CBCT reconstructions were used for 12 patients (6 brain, 3 prostate, and 3 bladder cancer patients). All patients were treated using Elekta linear accelerators and XVI imaging systems. Two of the CBCT number correction methods investigated were based on an algorithm previously proposed by the authors but only previously applied to phantoms. Two further methods, based on an approach previously suggested in the research literature, were also examined. Dose calculations were performed using scans of a 'worst' subset of patients using the Pinnacle{sup 3} version 9.0 treatment planning system and the patients' clinical plans. Results: All mean errors in CBCT number were <50 HU, and all correction methods performed well or adequately in dose calculations. The worst single dose discrepancy identified for any of the examined methods or patients was 3.0%. Mean errors in the doses to treatment volumes or organs at risk were negatively correlated with the mean error in CT number. That is, a mean CT number that was too large, averaged over the entire CBCT volume, implied an underdosing in a volume-of-interest and vice versa. Conclusions: Results suggest that (1) the correction of CBCT numbers to within a mean error of 50 HU in the scan volume provides acceptable discrepancies in dose (<3%) and (2) this is achievable with even quite unsophisticated correction methods.

  6. Cone Beam Computed Tomography-Derived Adaptive Radiotherapy for Radical Treatment of Esophageal Cancer

    SciTech Connect

    Hawkins, Maria A.; Brooks, Corrinne; Hansen, Vibeke N.; Aitken, Alexandra; Tait, Diana M.

    2010-06-01

    Purpose: To investigate the potential for reduction in normal tissue irradiation by creating a patient specific planning target volume (PTV) using cone beam computed tomography (CBCT) imaging acquired in the first week of radiotherapy for patients receiving radical radiotherapy. Methods and materials: Patients receiving radical RT for carcinoma of the esophagus were investigated. The PTV is defined as CTV(tumor, nodes) plus esophagus outlined 3 to 5 cm cranio-caudally and a 1.5-cm circumferential margin is added (clinical plan). Prefraction CBCT are acquired on Days 1 to 4, then weekly. No correction for setup error made. The images are imported into the planning system. The tumor and esophagus for the length of the PTV are contoured on each CBCT and 5 mm margin is added. A composite volume (PTV1) is created using Week 1 composite CBCT volumes. The same process is repeated using CBCT Week 2 to 6 (PTV2). A new plan is created using PTV1 (adaptive plan). The coverage of the 95% isodose of PTV1 is evaluated on PTV2. Dose-volume histograms (DVH) for lungs, heart, and cord for two plans are compared. Results: A total of 139 CBCT for 14 cases were analyzed. For the adaptive plan the coverage of the 95% prescription isodose for PTV1 = 95.6% +- 4% and the PTV2 = 96.8% +- 4.1% (t test, 0.19). Lungs V20 (15.6 Gy vs. 10.2 Gy) and heart mean dose (26.9 Gy vs. 20.7 Gy) were significantly smaller for the adaptive plan. Conclusions: A reduced planning volume can be constructed within the first week of treatment using CBCT. A single plan modification can be performed within the second week of treatment with considerable reduction in organ at risk dose.

  7. Normal orbit skeletal changes in adolescents as determined through cone-beam computed tomography.

    PubMed

    Lee, B; Flores-Mir, C; Lagravère, M O

    2016-11-10

    To determine three-dimensional spatial orbit skeletal changes in adolescents over a 19 to 24 months observation period assessed through cone-beam computed tomography (CBCT). The sample consisted of 50 adolescents aged 11 to 17. All were orthodontic patients who had two CBCTs taken with an interval of 19 to 24 months between images. The CBCTs were analyzed using the third-party software Avizo. Sixteen anatomical landmarks resulting in 24 distances were used to measure spatial structural changes of both orbits. Reliability and measurement error of all landmarks were calculated using ten CBCTs. Descriptive and t-test statistical analyses were used to determine the overall changes in the orbits. All landmarks showed excellent reliability with the largest measurement error being the Y-coordinate of the left most medial point of the temporalis grooves at 0.95 mm. The mean differences of orbital changes between time 1 and time 2 in the transverse, antero-posterior and vertical directions were 0.97, 0.36 and 0.33 mm respectively. Right to left most antero-inferior superior orbital rim distance had the greatest overall transverse change of 4.37 mm. Right most posterior point of lacrimal crest to right most postero-lateral point of the superior orbital fissure had the greatest overall antero-posterior change of 0.52 mm. Lastly, left most antero-inferior superior orbital rim to left most antero-superior inferior orbital rim had the greatest overall vertical change of 0.63 mm. The orbit skeletal changes in a period of 19-24 months in a sample of 11-17 year olds were statistically significant, but are not considered to be clinically significant. The overall average changes of orbit measurements were less than 1 mm.

  8. Radiopacity of alloplastic bone grafts measured with cone beam computed tomography: An analysis in rabbit calvaria

    PubMed Central

    Bucchi, Cristina; Borie, Eduardo; Arias, Alain; Dias, Fernando José; Fuentes, Ramón

    2017-01-01

    Availability of adequate bone structure for dental implants is still a problem in dentistry. Alloplastic grafts, which promote bone regeneration, are used as bone substitutes in orthopedic and oral surgical procedures. The aim of this study was to evaluate the radiopacity of three different synthetic bone grafts in rabbit calvaria, over 3 months, using cone beam computed tomography (CBCT). Four critical-size defects were made on the calvaria of 11 rabbits. The lesions were classified into three groups according to the alloplastic grafts they received: Osteon® 70/30, Osteon collagen®, and Osteon II® groups. The fourth group received blood clot, and served as a control. The bone samples were collected and analyzed with CBCT after the 1st, 2nd, and 3rd month. One month after surgery, the lesions that received Osteon® 70/30 and Osteon collagen® grafts showed the highest radiopacity compared to the lesions with Osteon II® and blood clot. After the 2nd month, the radiopacity values between the three groups that received the grafts were more similar compared to the group with blood clot. After the 3rd month, the lesions with Osteon® 70/30 graft showed the highest radiopacity values, followed by Osteon collagen® and Osteon II® groups. The group that received blood clot showed the lowest radiopacity values. In conclusion, the grafts used in this study had higher radiopacity values compared to blood clot. Among the grafts used, the Osteon® 70/30 graft showed the highest radiopacity values in the 3-month period. PMID:27968706

  9. Three-dimensional cone-beam computed tomography for assessment of mandibular changes after orthognathic surgery

    PubMed Central

    Cevidanes, Lucia H. S.; Bailey, L'Tanya J.; Tucker, Scott F.; Styner, Martin A.; Mol, Andre; Phillips, Ceib L.; Proffit, William R.; Turvey, Timothy

    2013-01-01

    Introduction The purpose of this study was to assess alterations in the 3-dimensional (3D) position of the mandibular rami and condyles in patients receiving either maxillary advancement and mandibular setback or maxillary surgery only. Methods High-resolution cone-beam computed tomography scans were taken of 21 patients before and after orthognathic surgery. Ten patients with various malocclusions underwent maxillary surgery only, and 11 Class III patients received maxillary advancement and mandibular setback. Presurgery and postsurgery 3D models were registered on the surface of the cranial base. A new tool was used for graphical overlay and 3D display with color maps to visually assess the locations and to quantify positional changes in the posterior border of the mandibular rami and condyles between superimposed models. Results The average displacements in condylar position were small—0.77 mm (SD, 0.12 mm) and 0.70 mm (SD, 0.08 mm)—for 2-jaw and 1-jaw surgeries, respectively (not significant, P >.05). All 2-jaw surgery patients had backward rotational displacements of the mandibular rami (mean, 1.98 mm; SD, 1.03 mm), with a maximum surface distance change of ≥2 mm in 8 of 11 subjects. For the 1-jaw surgery, all subjects had small backward rotational displacements of the mandibular rami (mean, 0.78 mm; SD, 0.25 mm), with only 1 subject having a maximum surface distance change ≥2 mm. The difference in mean backward rotational displacement was statistically significant (P <.01). Conclusions The visualization of 3D model superimposition clearly identified the location, magnitude, and direction of mandibular displacement. The 3D imaging allowed quantification of vertical, transverse, and anteroposterior ramus displacement that accompanied mandibular, but not maxillary only, surgery. PMID:17208105

  10. Comparison of mesiodistal root angulation with posttreatment panoramic radiographs and cone-beam computed tomography

    PubMed Central

    Bouwens, Daniel G.; Cevidanes, Lucia; Ludlow, John B.; Phillips, Ceib

    2011-01-01

    Introduction Orthodontists assess mesiodistal root angulations before, during, and after orthodontic treatment as an aid in establishing proper root position. Panoramic imaging has been useful for this purpose and is a valuable screening tool in diagnosis and planning treatment of orthodontic patients. Cone-beam computed tomography (CBCT) for imaging of the craniofacial complex creates the opportunity to evaluate 3-dimensional images compared with traditional 2-dimensional images. The purpose of this project was to compare mesiodistal root angulations by using posttreatment panoramic radiographic images and CBCT scans. Methods Mesiodistal root angulations from panoramic images and CBCT scans of 35 orthognathic surgery patients after orthodontic treatment were compared. The panoramic images were measured by using VixWin (Gendex Dental Systems, Des Plaines, Ill), and the CBCT scans by using InvivoDental 3D (version 4.1, Anatomage, San Jose, Calif). The mesiodistal root angulation of each maxillary and mandibular tooth was measured by using the occlusal plane as the reference line. With an intercept-only linear regression for correlated data (with an unstructured covariance structure), the global test of whether the mean vector of all differences for the teeth is zero was performed separately for the 2 arches. Results The global test for both arches was statistically significant (P<0.001), indicating an overall difference in root angulation between measurements from panoramic and CBCT images. There was no discernible pattern in the average differences between panoramic and CBCT measurements. Conclusions The assessment of mesiodistal tooth angulation with panoramic radiography should be approached with caution and reinforced by a thorough clinical examination of the dentition. PMID:21195286

  11. Respiratory triggered 4D cone-beam computed tomography: A novel method to reduce imaging dose

    SciTech Connect

    Cooper, Benjamin J.; O'Brien, Ricky T.; Keall, Paul J.; Balik, Salim; Hugo, Geoffrey D.

    2013-04-15

    Purpose: A novel method called respiratory triggered 4D cone-beam computed tomography (RT 4D CBCT) is described whereby imaging dose can be reduced without degrading image quality. RT 4D CBCT utilizes a respiratory signal to trigger projections such that only a single projection is assigned to a given respiratory bin for each breathing cycle. In contrast, commercial 4D CBCT does not actively use the respiratory signal to minimize image dose. Methods: To compare RT 4D CBCT with conventional 4D CBCT, 3600 CBCT projections of a thorax phantom were gathered and reconstructed to generate a ground truth CBCT dataset. Simulation pairs of conventional 4D CBCT acquisitions and RT 4D CBCT acquisitions were developed assuming a sinusoidal respiratory signal which governs the selection of projections from the pool of 3600 original projections. The RT 4D CBCT acquisition triggers a single projection when the respiratory signal enters a desired acquisition bin; the conventional acquisition does not use a respiratory trigger and projections are acquired at a constant frequency. Acquisition parameters studied were breathing period, acquisition time, and imager frequency. The performance of RT 4D CBCT using phase based and displacement based sorting was also studied. Image quality was quantified by calculating difference images of the test dataset from the ground truth dataset. Imaging dose was calculated by counting projections. Results: Using phase based sorting RT 4D CBCT results in 47% less imaging dose on average compared to conventional 4D CBCT. Image quality differences were less than 4% at worst. Using displacement based sorting RT 4D CBCT results in 57% less imaging dose on average, than conventional 4D CBCT methods; however, image quality was 26% worse with RT 4D CBCT. Conclusions: Simulation studies have shown that RT 4D CBCT reduces imaging dose while maintaining comparable image quality for phase based 4D CBCT; image quality is degraded for displacement based RT 4D

  12. Malocclusion Class II division 1 skeletal and dental relationships measured by cone-beam computed tomography.

    PubMed

    Xu, Yiling; Oh, Heesoo; Lagravère, Manuel O

    2017-09-01

    The purpose of this study was to locate traditionally-used landmarks in two-dimensional (2D) images and newly-suggested ones in three-dimensional (3D) images (cone-beam computer tomographies [CBCTs]) and determine possible relationships between them to categorize patients with Class II-1 malocclusion. CBCTs from 30 patients diagnosed with Class II-1 malocclusion were obtained from the University of Alberta Graduate Orthodontic Program database. The reconstructed images were downloaded and visualized using the software platform AVIZO(®). Forty-two landmarks were chosen and the coordinates were then obtained and analyzed using linear and angular measurements. Ten images were analyzed three times to determine the reliability and measurement error of each landmark using Intra-Class Correlation coefficient (ICC). Descriptive statistics were done using the SPSS statistical package to determine any relationships. ICC values were excellent for all landmarks in all axes, with the highest measurement error of 2mm in the y-axis for the Gonion Left landmark. Linear and angular measurements were calculated using the coordinates of each landmark. Descriptive statistics showed that the linear and angular measurements used in the 2D images did not correlate well with the 3D images. The lowest standard deviation obtained was 0.6709 for S-GoR/N-Me, with a mean of 0.8016. The highest standard deviation was 20.20704 for ANS-InfraL, with a mean of 41.006. The traditional landmarks used for 2D malocclusion analysis show good reliability when transferred to 3D images. However, they did not reveal specific skeletal or dental patterns when trying to analyze 3D images for malocclusion. Thus, another technique should be considered when classifying 3D CBCT images for Class II-1malocclusion. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

  13. Enhancement of four-dimensional cone-beam computed tomography by compressed sensing with Bregman iteration.

    PubMed

    Choi, Kihwan; Fahimian, Benjamin P; Li, Tianfang; Suh, Tae-Suk; Lei, Xing

    2013-01-01

    In four-dimensional (4D) cone-beam computed tomography (CBCT), there is a spatio-temporal tradeoff that currently limits the accuracy. The aim of this study is to develop a Bregman iteration based formalism for high quality 4D CBCT image reconstruction from a limited number of low-dose projections. The 4D CBCT problem is first divided into multiple 3D CBCT subproblems by grouping the projection images corresponding to the phases. To maximally utilize the information from the under-sampled projection data, a compressed sensing (CS) method with Bregman iterations is employed for solving each subproblem. We formulate an unconstrained optimization problem based on least-square criterion regularized by total-variation. The least-square criterion reflects the inconsistency between the measured and the estimated line integrals. Furthermore, the unconstrained problem is updated and solved repeatedly by Bregman iterations. The performance of the proposed algorithm is demonstrated through a series of simulation studies and phantom experiments, and the results are compared to those of previously implemented compressed sensing technique using other gradient-based methods as well as conventional filtered back-projection (FBP) results. The simulation and experimental studies have shown that artifact suppressed images can be obtained with as small as 41 projections per phase, which is adequate for clinical 4D CBCT reconstruction. With such small number of projections, the conventional FDK failed to yield meaningful 4D CBCT images, and CS technique using conjugate gradient was not able to recover sharp edges. The proposed method significantly reduces the radiation dose and scanning time to achieve the high quality images compared to the 4D CBCT imaging based on the conventional FDK technique and the existing CS techniques.

  14. Accuracy of Linear Measurements Using Cone Beam Computed Tomography in Comparison with Clinical Measurements

    PubMed Central

    Rokn, Amir Reza; Hashemi, Kazem; Akbari, Solmaz; Kharazifard, Mohammad Javad; Barikani, Hamidreza; Panjnoosh, Mehrdad

    2016-01-01

    Objectives: This study sought to evaluate the accuracy and errors of linear measurements of mesiodistal dimensions of Kennedy Class III edentulous space using cone beam computed tomography (CBCT) in comparison with clinical measurements. Materials and Methods: Nineteen Kennedy Class III dental arches were evaluated. An impression was made of each dental arch and poured with dental stone. The distance was measured on dental cast using a digital Vernier caliper with an accuracy of 0.1mm and on CBCT scans. Finally, the linear mesiodistal measurements were compared and the accuracy of CBCT technique was evaluated by calculating absolute value of errors, intra-class correlation coefficient and simple linear regression model. Results: In comparison with the cast method, estimation of size on CBCT scans had an error of −8.46% (underestimation) to 5.21% (overestimation). In 26.5% of the cases, an accepted error of ±1% was found. The absolute value of errors was found to be in the range of 0.21–8.46mm with an average value of 2.86 ±2.30mm. Conclusions: Although the measurements revealed statistically significant differences, this does not indicate a lower accuracy for the CBCT technique. In fact, CBCT can provide some information as a paraclinical tool and the clinician can combine these data with clinical data and achieve greater accuracy. Undoubtedly, calibration of data collected by clinical and paraclinical techniques and the clinician’s expertise in use of CBCT software programs can increase the accuracy of implant placement. PMID:28127327

  15. Characteristics of noise and resolution on image reconstruction in cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Lee, Seung-wan; Kim, Hee-Joung; Lee, Chang-Lae; Cho, Hyo-Min; Park, Hye-Suk; Kim, Dae-Hong; Choi, Yu-Na; Ryu, Hyun-Ju

    2011-03-01

    The cone-beam computed tomography (CBCT) is a useful modality in diagnostic imaging due to the properties of fast volume coverage, lower radiation dose, easy hardware implementation, and higher spatial resolution. Recently, attention is being paid to address the noise and resolution relationship for CBCT. In CBCT system, image noise and spatial resolution play important roles in image quality. However, there has not been done many works for evaluating the relationship of image noise and the spatial resolution in CBCT. In this study, we evaluated the image noise and spatial resolution as a function of filter, number of projections, and voxel size on reconstructed images in CBCT. The simulated projection data of Catphan 600 phantom were reconstructed using the FDK algorithm. To evaluate the image noise and spatial resolution, the coefficient of variation (COV) of attenuation coefficient and the modulation transfer function (MTF) in axial images were calculated, respectively. The filters used for reconstruction were Ram-lak, Shepp-logan, Cosine, Hamming, and Hann. A number of projections were 161, 321, 481 and 642 acquired from scanning of 360 degree and the voxels with sizes of 0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm and 0.30 mm were used. The image noise given by Hann filter was the lowest and decreased as functions of number of projections and voxel size. The spatial resolution given by Ram-lak filter was the highest and increased as a function of number of projections, decreased as a function of voxel size. The results of this study show the relationship of image noise and spatial resolution in CBCT and the characteristics of reconstruction factors for trade-off between the image noise and spatial resolution. It can also provide information of image noise and spatial resolution for adaptive image.

  16. Quality and accuracy of cone beam computed tomography gated by active breathing control

    PubMed Central

    Thompson, Bria P.; Hugo, Geoffrey D.

    2008-01-01

    The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breathing), and free breathing respiration correlated CBCT. Image quality was assessed in phantom. Accuracy of reconstructed voxel intensity, uniformity, and root mean square error were evaluated. Registration accuracy (bony and soft tissue) was quantified with both an anthropomorphic and a quality assurance phantom. Gantry angle accuracy was measured with respect to gantry speed modulation. Conventional ABC-CBCT scan time ranged from 2.3 to 5.8 min. Fast ABC-CBCT scan time ranged from 1.4 to 1.8 min, and respiratory correlated CBCT scans took 2.1 min to complete. Voxel intensity value for ABC gated scans was accurate relative to a normal clinical scan with all projections. Uniformity and root mean square error performance degraded as the number of projections used in the reconstruction of the fast ABC-CBCT scans decreased (shortest breath hold, longest free breathing segment). Registration accuracy for small, large, and rotational corrections was within 1 mm and 1°. Gantry angle accuracy was within 1° for all scans. For high-contrast targets, performance for image-guidance purposes was similar for fast and conventional ABC-CBCT scans and respiration correlated CBCT. PMID:19175117

  17. A Cone-Beam Computed Tomographic Study on Mandibular First Molars in a Chinese Subpopulation.

    PubMed

    Zhang, Xin; Xiong, Shijiang; Ma, Yue; Han, Ting; Chen, Xinyu; Wan, Fang; Lu, Yating; Yan, Songhe; Wang, Yan

    2015-01-01

    The purpose of this study was to conduct a cone-beam computed tomographic (CBCT) investigation on the root and canal configuration of the mandibular first molars, especially the morphology of the disto-lingual (DL) root, in a Chinese subpopulation. A total of 910 CBCT images of the mandibular first molars were collected from 455 patients who underwent CBCT examinations as a preoperative assessment for implants or orthodontic treatment. The following information was analyzed and evaluated: tooth position, gender, root and root canal number per tooth, root canal type of the mesial root(s) and distal root(s), angle of the DL root canal curvature, distance between two distal canal orifices in the teeth with DL root, and angle of disto-buccal canal orifice-disto-lingual canal orifice-mesio-lingual canal orifice (DB-DL-ML). Most of the mandibular first molars (64.9%, n = 591) had two roots with three root canals, and most of the mesial root canals (87.7%, n = 798) were type VI. The prevalence of the DL root was 22.1% (n = 201). The right side had a higher prevalence of DL root than the left side (p<0.05). Additionally, the curvature of the DL root canal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (p<0.05). Overall there was a high prevalence of DL root in the mandibular first molars, and most of the DL roots were curved in different degrees. This study provided detailed information about the root canal morphology of the mandibular first molars in a Chinese subpopulation.

  18. Automatic Synthesis of Panoramic Radiographs from Dental Cone Beam Computed Tomography Data

    PubMed Central

    Luo, Ting; Shi, Changrong; Zhao, Xing; Zhao, Yunsong; Xu, Jinqiu

    2016-01-01

    In this paper, we propose an automatic method of synthesizing panoramic radiographs from dental cone beam computed tomography (CBCT) data for directly observing the whole dentition without the superimposition of other structures. This method consists of three major steps. First, the dental arch curve is generated from the maximum intensity projection (MIP) of 3D CBCT data. Then, based on this curve, the long axial curves of the upper and lower teeth are extracted to create a 3D panoramic curved surface describing the whole dentition. Finally, the panoramic radiograph is synthesized by developing this 3D surface. Both open-bite shaped and closed-bite shaped dental CBCT datasets were applied in this study, and the resulting images were analyzed to evaluate the effectiveness of this method. With the proposed method, a single-slice panoramic radiograph can clearly and completely show the whole dentition without the blur and superimposition of other dental structures. Moreover, thickened panoramic radiographs can also be synthesized with increased slice thickness to show more features, such as the mandibular nerve canal. One feature of the proposed method is that it is automatically performed without human intervention. Another feature of the proposed method is that it requires thinner panoramic radiographs to show the whole dentition than those produced by other existing methods, which contributes to the clarity of the anatomical structures, including the enamel, dentine and pulp. In addition, this method can rapidly process common dental CBCT data. The speed and image quality of this method make it an attractive option for observing the whole dentition in a clinical setting. PMID:27300554

  19. Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography

    PubMed Central

    Soukup, Jason W.; Drees, Randi; Koenig, Lisa J.; Snyder, Christopher J.; Hetzel, Scott; Miles, Chanda R.; Schwarz, Tobias

    2016-01-01

    Summary The objective of this blinded study was to validate the use of cone beam computed tomography (CT) for imaging of the canine maxillary dentoalveolar structures by comparing its diagnostic image quality with that of 64-multidetector row CT. Sagittal slices of a tooth-bearing segment of the maxilla of a commercially purchased dog skull embedded in methyl methacrylate were obtained along a line parallel with the dental arch using a commercial histology diamond saw. The slice of tooth-bearing bone that best depicted the dentoalveolar structures was chosen and photographed. The maxilla segment was imaged with cone beam CT and 64-multidetector row CT. Four blinded evaluators compared the cone beam CT and 64-multidetector row CT images and image quality was scored as it related to the anatomy of dentoalveolar structures. Trabecular bone, enamel, dentin, pulp cavity, periodontal ligament space, and lamina dura were scored. In addition, a score depicting the evaluators overall impression of the image was recorded. Images acquired with cone beam CT were found to be significantly superior in image quality to images acquired with 64-multidetector row CT overall, and in all scored categories. In our study setting, cone beam CT was found to be a valid and clinically superior imaging modality for the canine maxillary dentoalveolar structures when compared to 64-multidetector row CT. PMID:26415384

  20. Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography.

    PubMed

    Soukup, Jason W; Drees, Randi; Koenig, Lisa J; Snyder, Christopher J; Hetzel, Scott; Miles, Chanda R; Schwarz, Tobias

    2015-01-01

    The objective of this blinded study was to validate the use of cone beam computed tomography (C) for imaging of the canine maxillary dentoalveolar structures by comparing its diagnostic image quality with that of 64-multidetector row CT Sagittal slices of a tooth-bearing segment of the maxilla of a commercially purchased dog skull embedded in methylmethacrylate were obtained along a line parallel with the dental arch using a commercial histology diamond saw. The slice of tooth-bearing bone that best depicted the dentoalveolar structures was chosen and photographed. The maxillary segment was imaged with cone beam CT and 64-multidetector row CT. Four blinded evaluators compared the cone beam CT and 64-multidetector row CT images and image quality was scored as it related to the anatomy of dentoalveolar structures. Trabecular bone, enamel, dentin, pulp cavity, periodontal ligament space, and lamina dura were scored In addition, a score depicting the evaluators overall impression of the image was recorded. Images acquired with cone beam CT were found to be significantly superior in image quality to images acquired with 64-multidetector row CT overall, and in all scored categories. In our study setting cone beam CT was found to be a valid and clinically superior imaging modality for the canine maxillary dentoalveolar structures when compared to 64-multidetector row CT.

  1. Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones.

    PubMed

    Ho, Jung-Ting; Wu, Jay; Huang, Heng-Li; Chen, Michael Y c; Fuh, Lih-Jyh; Hsu, Jui-Ting

    2013-11-09

    This study compared the adequacy of dental cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) in evaluating the structural parameters of trabecular bones. The cellular synthetic bones in 4 density groups (Groups 1-4: 0.12, 0.16, 0.20, and 0.32 g/cm3) were used in this study. Each group comprised 8 experimental specimens that were approximately 1 cm3. Dental CBCT and micro-CT scans were conducted on each specimen to obtain independent measurements of the following 4 trabecular bone structural parameters: bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th.), and trabecular separation (Tb.Sp.). Wilcoxon signed ranks tests were used to compare the measurement variations between the dental CBCT and micro-CT scans. A Spearman analysis was conducted to calculate the correlation coefficients (r) of the dental CBCT and micro-CT measurements. Of the 4 groups, the BV/TV and Tb.Th. measured using dental CBCT were larger compared with those measured using micro-CT. By contrast, the BS/BV measured using dental CBCT was significantly less compared with those measured using micro-CT. Furthermore, in the low-density groups (Groups 1 and 2), the Tb.Sp. measured using dental CBCT was smaller compared with those measured using micro-CT. However, the Tb.Sp. measured using dental CBCT was slightly larger in the high-density groups (Groups 3 and 4) than it was in the low density groups. The correlation coefficients between the BV/TV, BS/BV, Tb.Th., and Tb.Sp. values measured using dental CBCT and micro-CT were 0.9296 (p < .001), 0.8061 (p < .001), 0.9390 (p < .001), and 0.9583 (p < .001), respectively. Although the dental CBCT and micro-CT approaches exhibited high correlations, the absolute values of BV/TV, BS/BV, Tb.Th., Tb.Sp. differed significantly between these measurements. Additional studies must be conducted to evaluate using dental CBCT in clinical practice.

  2. Beam hardening artifacts by dental implants: Comparison of cone-beam and 64-slice computed tomography scanners

    PubMed Central

    Esmaeili, Farzad; Johari, Masume; Haddadi, Pezhman

    2013-01-01

    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. PMID:24019808

  3. Image calibration and registration in cone-beam computed tomogram for measuring the accuracy of computer-aided implant surgery

    NASA Astrophysics Data System (ADS)

    Lam, Walter Y. H.; Ngan, Henry Y. T.; Wat, Peter Y. P.; Luk, Henry W. K.; Goto, Tazuko K.; Pow, Edmond H. N.

    2015-02-01

    Medical radiography is the use of radiation to "see through" a human body without breaching its integrity (surface). With computed tomography (CT)/cone beam computed tomography (CBCT), three-dimensional (3D) imaging can be produced. These imagings not only facilitate disease diagnosis but also enable computer-aided surgical planning/navigation. In dentistry, the common method for transfer of the virtual surgical planning to the patient (reality) is the use of surgical stent either with a preloaded planning (static) like a channel or a real time surgical navigation (dynamic) after registration with fiducial markers (RF). This paper describes using the corner of a cube as a radiopaque fiducial marker on an acrylic (plastic) stent, this RF allows robust calibration and registration of Cartesian (x, y, z)- coordinates for linking up the patient (reality) and the imaging (virtuality) and hence the surgical planning can be transferred in either static or dynamic way. The accuracy of computer-aided implant surgery was measured with reference to coordinates. In our preliminary model surgery, a dental implant was planned virtually and placed with preloaded surgical guide. The deviation of the placed implant apex from the planning was x=+0.56mm [more right], y=- 0.05mm [deeper], z=-0.26mm [more lingual]) which was within clinically 2mm safety range. For comparison with the virtual planning, the physically placed implant was CT/CBCT scanned and errors may be introduced. The difference of the actual implant apex to the virtual apex was x=0.00mm, y=+0.21mm [shallower], z=-1.35mm [more lingual] and this should be brought in mind when interpret the results.

  4. Analysis of linear measurement accuracy obtained by cone beam computed tomography (CBCT-NewTom VG).

    PubMed

    Moshfeghi, Mahkameh; Tavakoli, Mohammad Amin; Hosseini, Ehsan Tavakoli; Hosseini, Ali Tavakoli; Hosseini, Iman Tavakoli

    2012-12-01

    One of the major uses of cone beam computed tomography (CBCT) is presurgical implant planning. Linear measurement is used for the determination of the quantity of alveolar bone (height and width). Linear measurements are used in orthodontic analysis and definition of jaw tumor size. The objective of this study is to evaluate the accuracy of the linear measurement of CBCT (Newtom VG) in the axial and coronal planes, with two different voxel sizes. In this accuracy diagnostic study, 22 anatomic landmarks in four dry human skulls were marked by gutta-percha. Fifteen linear measurements were obtained using a digital caliper. These were considered to be the gold standard (real measurement). The skulls were scanned by CBCT (Newtom VG) at two settings: (a) Voxel size 0.3 mm (b) voxel size 0.15 mm High Resolution (HR). The radiographic distance measurements were made in the axial and coronal sections by three observers. The radiographic measurements were repeated two weeks later for evaluation of intraobserver reliability. SPSS software version 17 was used for data analysis. The level of significance was considered to be 5% (P ≤ 0.05). The mean differences of real and radiographic measurements were -0.10±0.99 mm in the axial sections, -0.27±1.07 mm in the coronal sections, +0.14±1.44 mm in the axial (HR) sections, and 0.02±1.4 mm in the coronal (HR) sections. The intraclass correlation (ICC) for CBCT measurements in the axial sections was 0.9944, coronal sections 0.9941, axial (HR) sections 0.9935, and coronal (HR) sections 0.9937. The statistical analysis showed high interobserver and intraobserver reliability (P ≤ 0.05). CBCT (Newtom VG) is highly accurate and reproducible in linear measurements in the axial and coronal image planes and in different areas of the maxillofacial region. According to the findings of the present study, a CBCT scan with a larger voxel size (0.3 mm in comparison to 0.15 mm) is recommended when the purpose of the CBCT scan is to measure

  5. Diagnostic accuracy of cone beam computed tomography in identification and postoperative evaluation of furcation defects

    PubMed Central

    Pajnigara, Natasha; Kolte, Abhay; Kolte, Rajashri; Pajnigara, Nilufer; Lathiya, Vrushali

    2016-01-01

    Background: Decision-making in periodontal therapeutics is critical and is influenced by accurate diagnosis of osseous defects, especially furcation involvement. Commonly used diagnostic methods such as clinical probing and conventional radiography have their own limitations. Hence, this study was planned to evaluate the dimensions of furcation defects clinically (pre- and post-surgery), intra-surgically, and by cone beam computed tomography (CBCT) (pre- and post-surgery). Materials and Methods: The study comprised a total of 200 Grade II furcation defects in forty patients, with a mean age of 38.05 ± 4.77 years diagnosed with chronic periodontitis which were evaluated clinically (pre- and post-surgically), by CBCT (pre- and post-surgically), and intrasurgically after flap reflection (40 defects in each). After the presurgical clinical and CBCT measurements, demineralized freeze-dried bone allograft was placed in the furcation defect and the flaps were sutured back. Six months later, these defects were evaluated by recording measurements clinically, i.e., postsurgery clinical measurements and also postsurgery CBCT measurements (40 defects each). Results: Presurgery clinical measurements (vertical 6.15 ± 1.71 mm and horizontal 3.05 ± 0.84 mm) and CBCT measurements (vertical 7.69 ± 1.67 mm and horizontal 4.62 ± 0.77 mm) underestimated intrasurgery measurements (vertical 8.025 ± 1.67 mm and horizontal 4.82 ± 0.67 mm) in both vertical and horizontal aspects, and the difference was statistically not significant (vertical P = 1.000, 95% confidence interval [CI], horizontal P = 0.867, 95% CI). Further, postsurgery clinical measurements (vertical 2.9 ± 0.74 mm and horizontal 1.52 ± 0.59 mm) underestimated CBCT measurements (vertical 3.67 ± 1.17 mm and horizontal 2.45 ± 0.48 mm). There was statistically significant difference between presurgery clinical–presurgery CBCT (P < 0.0001, 95% CI) versus postsurgery clinical–postsurgery CBCT (P < 0.0001, 95% CI

  6. Correction for patient table-induced scattered radiation in cone-beam computed tomography (CBCT)1

    PubMed Central

    Sun, Mingshan; Nagy, Tamás; Virshup, Gary; Partain, Larry; Oelhafen, Markus; Star-Lack, Josh

    2011-01-01

    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 pelvis phantom were

  7. Radiographic Appearance of Interocclusal Record Materials for Cone Beam Computed Tomography-Guided Implant Surgeries.

    PubMed

    Mohunta, Vrinda V; McGlumphy, Edwin A; Kim, Do-Gyoon; Azer, Shereen S

    To select an ideal interocclusal record material for cone beam computed tomography (CBCT)-guided implant surgery based on the material's radiodensity on the scan. Twelve commonly used interocclusal record materials were used for this investigation: two were waxes, one was polyether, and nine were polyvinyl-siloxane-type materials. A scan template was fabricated by duplicating existing dentures in Ortho-Jet acrylic resin mixed with 30% barium powder for the teeth and 10% barium powder for the denture base between the teeth and the tissue. An interocclusal record was fabricated with each material, and the same template was used to obtain a CBCT scan with an ICAT machine (Imaging Sciences International) at 0.3 voxel and 14-bit depth settings. Twelve CBCT scans were obtained and analyzed. The radiopacity of the barium teeth was used as a control and was compared with the opacity of the 12 materials using a paired t test. A post hoc analysis of variance (ANOVA) test was used to compare the densities of the various materials with each other. There was a statistically significant difference between the radiopacity of barium teeth (gray value: 1,959.475) and that of Modelling Wax (gray value: 750; P = .0026), Aluwax (gray value: 795.22; P = .0022), Blu-Bite CT (gray value: 1,105; P = .005), Ramitec (gray value: 1,105.3; P = .08), Memosil 2 (gray value: 1,202; P = .01) followed by Reprosil (gray value: 1,407.73; P = .01). Compared with the barium teeth, there was no statistically significant difference between the densities of Futar D (gray value: 1,866.5; P = .51), Jet Bite (gray value: 1,660.04; P = .08), Lab-Putty (gray value: 1,402.14; P = .19), and Memoreg 2 (gray value: 1,754.72; P = .1). The highest radiodensity was seen with Blu-Mousse (gray value: 2,949; P = .007) and Take 1 (gray value: 2,229.85; P = .025), which were also significantly different from the density of the barium teeth but in the opposite direction, making them more opaque. Within the limitations of

  8. Assessment of three dead detector correction methods for cone-beam computed tomography

    SciTech Connect

    Nelms, David W.; Shukla, Hemant I.; Nixon, Earl; Bayouth, John E.; Flynn, Ryan T.

    2009-10-15

    Purpose: Dead detectors due to manufacturing defects or radiation damage in the electronic portal imaging devices (EPIDs) used for cone-beam computed tomography (CBCT) can lead to image degradation and ring artifacts. In this work three dead detector correction methods were assessed using megavoltage CBCT (MVCBCT) as a test system, with the goals of assessing the relative effectiveness of the three methods and establishing the conditions for which they fail. Methods: MVCBCT projections acquired with four linacs at 8 and 60 MU (monitor units) were degraded with varying percentages (2%-95%) of randomly distributed dead single detectors (RDSs), randomly distributed dead detector clusters (RDCs) of 2 mm diameter, and nonrandomly distributed dead detector disks (NRDDs) of varying diameter (4-16 mm). Correction algorithms were bidirectional linear interpolation (BLI), quad-directional linear interpolation (QLI), and a Laplacian solution (LS) method. Correction method failure was defined to occur if ring artifacts were present in the reconstructed phantom images from any linac or if the modulation transfer function (MTF) for any linac dropped below baseline with a p value, calculated with the two sample t test, of less than 0.01. Results: All correction methods failed at the same or lower RDC/RDS percentages and NRDD diameters for the 60 MU as for the 8 MU cases. The LS method tended to outperform or match the BLI and QLI methods. If ring artifacts anywhere in the images were considered unacceptable, the LS method failed for 60 MU at >33% RDS, >2% RDC, and >4 mm NRDD. If ring artifacts within 4 mm longitudinally of the phantom section interfaces were considered acceptable, the LS method failed for 60 MU at >90% RDS, >80% RDC, and >4 mm NRDD. LS failed due to MTF drop for 60 MU at >50% RDS, >25% RDC, and >4 mm NRDD. Conclusions: The LS method is superior to the BLI and QLI methods, and correction algorithm effectiveness decreases as imaging dose increases. All correction

  9. Assessment of cone beam computed tomography techniques for imaging lung damage in mice in vivo

    NASA Astrophysics Data System (ADS)

    Cavanaugh, Dawn

    Lung damage is a common side effect of chemotherapeutic drugs such as bleomycin. This study used a bleomycin mouse model which simulates the lung damage observed in humans. Noninvasive, in vivo cone-beam computed tomography (CBCT) was used to visualize and quantify fibrotic and inflammatory damage over the entire lung volume of mice. Bleomycin was used to induce pulmonary damage in vivo and the results from two CBCT systems, a micro-CT and flat panel CT (fpCT), were compared to histologic measurements, the standard method of murine lung damage quantification. Twenty C57BL/6 mice were given either 3 U/kg of bleomycin or saline intratracheally. The mice were scanned at baseline, before the administration of bleomycin, and then 10, 14, and 21 days afterward. At each time point, a subset of mice was sacrificed for histologic analysis. The resulting CT images were used to assess lung volume. Percent lung damage (PLD) was calculated for each mouse on both the fpCT (PLDfpcT) and the micro-CT (PLDmuCT). Histologic PLD (PLDH) was calculated for each histologic section at each time point (day 10, n = 4; day 14, n = 4; day 21, n = 5; control group, n = 5). A linear regression was applied to the PLDfpCT vs. PLDH, PLDmuCT vs. PLDH and PLDfpCT vs. PLDmuCT distributions. This study did not demonstrate strong correlations between PLDCT and PLDH. The coefficient of determination, R, was 0.68 for PLDmuCT vs. PLDH and 0.75 for the PLD fpCT vs. PLDH. The experimental issues identified from this study were: (1) inconsistent inflation of the lungs from scan to scan, (2) variable distribution of damage (one histologic section not representative of overall lung damage), (3) control mice not scanned with each group of bleomycin mice, (4) two CT systems caused long anesthesia time for the mice, and (5) respiratory gating did not hold the volume of lung constant throughout the scan. Addressing these issues might allow for further improvement of the correlation between PLDCT and PLDH.

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

    SciTech Connect

    Sun Mingshan; Nagy, Tamas; Virshup, Gary; Partain, Larry; Oelhafen, Markus; Star-Lack, Josh

    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 pelvis phantom were

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

    PubMed

    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

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

    SciTech Connect

    Li, Winnie; Sahgal, Arjun; Foote, Matthew; Millar, Barbara-Ann; Jaffray, David A.; Letourneau, Daniel

    2012-10-01

    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 Degree-Sign to 1.6 Degree-Sign , 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

  13. Target-specific optimization of four-dimensional cone beam computed tomography

    SciTech Connect

    Ahmad, Moiz; Pan Tinsu

    2012-09-15

    Purpose: Under-sampling artifacts are a major problem in four-dimensional cone-beam computed tomography (4D-CBCT) and may compromise evaluation of target motion. Several studies have addressed scan parameter selection for minimizing under-sampling artifacts; however, the role of the target characteristics in scan parameter selection has not been investigated. In this work, the authors evaluated 4D-CBCT performance by assessing the accuracy of target motion measurements for various target sizes and motions. The results may serve as patient-specific guidelines for scan parameters selection in 4D-CBCT. Methods: The authors acquired 4D-CBCT scans of a moving phantom consisting of six water-filled sphere targets of sizes 10-37 mm, using various scan times ranging from 30 s to 3 min., setting the motion to 3-s and 6-s periods. The authors used automatic image registration to extract the target motion trajectories and evaluated these measurements for various target sizes and motions over various combinations of scan parameters including scan time, detector configuration, number of respiration phases, and reconstruction filters. Results: The most important object parameter to 4D-CBCT performance was the period of motion. Measurements for the 6-s motion were always systematically less accurate than measurements for the 3-s motion for 34 of 36 objects of various sizes and periods of motion. The 6-s motion required a greater scan time than the 3-s motion for equivalent measurement accuracy. The second most influential parameter was the target size. For the 3-s period of motion, objects larger than 13 mm were tracked with sub-millimeter accuracy with a 1-min scan time. For the 6-s period of motion, objects larger than 22-mm were tracked with sub-millimeter accuracy with a 1.5-min scan time. For all sizes and motions, temporal blurring was observed when the number of phases was fewer than 8. Offset detector configuration provided the same performance as centered detector except

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

    SciTech Connect

    Akino, Yuichi; Yoshioka, Yasuo; Fukuda, Shoichi; Maruoka, Shintaroh; Takahashi, Yutaka; Yagi, Masashi; Mizuno, Hirokazu; Isohashi, Fumiaki; Ogawa, Kazuhiko

    2013-11-01

    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 (R{sup 2}=0.18±0.13), the displacement of the center of gravity of rectal contours in the anterior-posterior (AP) direction showed an intermediate relationship (R{sup 2}=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.

  15. A Survey of Cone-beam Computed Tomographic Use among Endodontic Practitioners in the United States.

    PubMed

    Setzer, Frank C; Hinckley, Nathan; Kohli, Meetu R; Karabucak, Bekir

    2017-05-01

    Cone-beam computed tomographic (CBCT) imaging is an emerging technology for clinical endodontic practice. The aim of this study was to investigate the acceptance, accessibility, and usage of CBCT imaging among American Association of Endodontists members in the United States by means of an online survey. An invitation to participate in a web-based survey was sent to 3076 members of the American Association of Endodontists. The survey consisted of 8 questions on demographics, access to CBCT machines, field of view (FOV), frequency of use for particular applications, and reasons in case CBCT was not used. A total of 1083 participants completed the survey, giving an overall completed response rate of 35.2%; 80.30% of the participants had access to a CBCT scan, of which 50.69% (n = 443) were on-site and 49.31% (n = 431) were off-site, and 19.30% of all respondents denied having access to CBCT imaging. Limited FOV was used by 55.26% participants, 22.37% used larger FOV formats, and the remaining 22.37% were not sure about the format. There was a significantly greater usage of CBCT technology in residency programs (n = 78/84 [92.86%]) compared with practitioners who had finished an endodontic specialty program (n = 796/999 [79.68%]) (χ(2) = 10.30, P = .02). Practitioners used CBCT imaging "frequent" or "always" for internal or external resorptions (47.28%), preoperatively for surgical retreatment or intentional replantation (45.34%), missing canals (25.39%), preoperatively for nonsurgical retreatments (24.91%), differential diagnosis (21.16%), identifying periradicular lesions (18.26%), calcified cases (13.54%), immature teeth (4.71%), and to assess healing (3.87%). There was a significant difference in on-site and off-site CBCT imaging use for any of these applications (P < .001). Prevalent reasons for not using CBCT technology were cost (53.79%) and lack of installation space (8.29%). General concerns were expressed about resolution limitations, radiation

  16. Measurement of Crestal Cortical Bone Thickness at Implant Site: A Cone Beam Computed Tomography Study.

    PubMed

    Gupta, Ajai; Rathee, Suprabha; Agarwal, Jaihans; Pachar, Renu B

    2017-09-01

    Dental implants have emerged as a new treatment modality for the majority of patients complaining of missing teeth. Bone quantity and bone quality are among various factors which ensure the longevity of dental implant in the patient's mouth. The assessment of cortical bone thickness of the outer layer and the cancellous bone density by cone beam computed tomography (CBCT) has proved beneficial for the patient. This study aimed at presurgical measurement of crestal bone thickness at various implant sites using CBCT images. This study was conducted in the Department of Prosthodontics in the year 2015. It included 218 patients who wanted to replace missing teeth. Patients were subjected to CBCT scan using NewTom CBCT machine operating at 120 kVp and 5 mA with a resolution of 0.1 × 0.1 × 0.1 mm(3). New Net Technologies (NNT) software with a slice thickness of 0.1 mm was used in this study. A total of 780 implant sites were identified on images of 218 patients. In all patients, the measurement of crestal bone thickness in the region of implant site was performed with NNT software. The buccolingual measurement of crestal bone was done in cross sections obtained after CBCT Results: Out of 218 patients, males were 110 and females were 108. The difference between gender was nonsignificant (p > 0.05). Out of 780 implant sites, 370 were in the maxilla and 410 were in mandible. The difference was nonsignificant (p > 0.05). Out of 780 implant sites, 210 were in anterior maxilla and 160 were in the posterior maxilla. Totally, 235 sites were in anterior mandible and 175 were in the posterior mandible. The distribution was nonsignificant (p = 0.15). The mean crestal bone thickness in anterior maxilla was 0.82 mm, in posterior maxilla was 0.76 mm, in anterior mandible was 1.08 mm, and in posterior mandible was 1.18 mm. The difference among regions was significant (p = 0.01). The highest thickness of cortical bone was observed in posterior mandible followed by anterior mandible

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

    PubMed Central

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

    2015-01-01

    Purpose The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients. Methods Two calibrated examiners analyzed a sample of 50 CBCT scans, performing morphometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the major axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P≤0.05 for the bone thickness means and standard deviations per tooth and patient for the five lines at varying depths. Results The means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall. Conclusions Less than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ≥2 mm. PMID:26550524

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

    PubMed Central

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

    2015-01-01

    Aim: The purpose of this study was to investigate, the condyle-fossa relationship, in clinically asymptomatic orthodontically untreated south Indian female volunteers, by cone-beam computed tomography (CBCT). Materials and Methods: The study population consisted of 13 clinically symptom-free and orthodontically untreated angle's Class I female subjects with the mean age of 18 years (ranges from 17 years to 20 years). The normal disc position of the 13 subjects was confirmed by history, clinical examination and magnetic resonance imaging scan. Then, the images of the temporomandibular joint (TMJ)of the subjects were taken using CBCT to evaluate the optimal condylar position. Posterior joint space (PS), superior joint space (SS) and anterior joint space (AS) were measured, and the values were subjected to statistical analysis. Mean PS, SS and AS of right and left side TMJ ' and AS of right sid 's were calculated. Paired samples t-test were used for each measurement to evaluate the average differences between the right and left side for each element of the sample. Results: The mean value of PS, SS and AS of right side TMJ 's were 2.1385, 2.2769 and 1.7615, respectively. The mean value of PS, SS and AS of left side TMJ 's were 2.1385, 2.5308 and 1.8538, respectively. Statistical analysis with the t-test indicated no significant differences in the AS, SS, or PS values between the right and left side. TMJ 's mean PS, SS, and AS measurements were2.1 mm (standard deviation [SD] ±0.65 mm), 2.4 mm (SD ± 0.58 mm), and 1.8 mm (SD ± 0.52 mm), respectively. The ratios of SS and PS to AS, with AS set to 1.0, were 1.3 and 1.2, respectively. Conclusion: These data from optimal joints might serve as norms for the clinical assessment of condylar position obtained by CBCT. PMID:26015688

  19. Accuracy of digital radiography and cone beam computed tomography on periapical radiolucency detection in endodontically treated teeth.

    PubMed

    Venskutonis, Tadas; Daugela, Povilas; Strazdas, Marijus; Juodzbalys, Gintaras

    2014-04-01

    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. 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. 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. 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.

  20. Three-dimensional cone-beam computed tomography analysis of enlargement of the pharyngeal airway by the Herbst appliance.

    PubMed

    Iwasaki, Tomonori; Takemoto, Yoshihiko; Inada, Emi; Sato, Hideo; Saitoh, Issei; Kakuno, Eriko; Kanomi, Ryuzo; Yamasaki, Youichi

    2014-12-01

    Pharyngeal airway size is increasingly recognized as an important factor in obstructive sleep apnea. However, few studies have examined the changes of pharyngeal airway form after dental procedures for treating obstructive sleep apnea during growth. The purpose of this study was to evaluate the effect of the Herbst appliance on the 3-dimensional form of the pharyngeal airway using cone-beam computed tomography. Twenty-four Class II subjects (ANB, ≥5°; 11 boys; mean age, 11.6 years) who required Herbst therapy with edgewise treatment had cone-beam computed tomography images taken before and after Herbst treatment. Twenty Class I control subjects (9 boys; mean age, 11.5 years) received edgewise treatment only. The volume, depth, and width of the pharyngeal airway were compared between the groups using measurements from 3-dimensional cone-beam computed tomography images of the entire pharyngeal airway. The increase of the oropharyngeal airway volume in the Herbst group (5000.2 mm(3)) was significantly greater than that of the control group (2451.6 mm(3)). Similarly, the increase of the laryngopharyngeal airway volume in the Herbst group (1941.8 mm(3)) was significantly greater than that of the control group (1060.1 mm(3)). The Herbst appliance enlarges the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth. Copyright © 2014 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  1. Breath-Hold Target Localization With Simultaneous Kilovoltage/Megavoltage Cone-Beam Computed Tomography and Fast Reconstruction

    SciTech Connect

    Blessing, Manuel; Stsepankou, Dzmitry; Wertz, Hansjoerg; Arns, Anna; Lohr, Frank; Hesser, Juergen; Wenz, Frederik

    2010-11-15

    Purpose: Hypofractionated high-dose radiotherapy for small lung tumors has typically been based on stereotaxy. Cone-beam computed tomography and breath-hold techniques have provided a noninvasive basis for precise cranial and extracranial patient positioning. The cone-beam computed tomography acquisition time of 60 s, however, is beyond the breath-hold capacity of patients, resulting in respiratory motion artifacts. By combining megavoltage (MV) and kilovoltage (kV) photon sources (mounted perpendicularly on the linear accelerator) and accelerating the gantry rotation to the allowed limit, the data acquisition time could be reduced to 15 s. Methods and Materials: An Elekta Synergy 6-MV linear accelerator, with iViewGT as the MV- and XVI as the kV-imaging device, was used with a Catphan phantom and an anthropomorphic thorax phantom. Both image sources performed continuous image acquisition, passing an angle interval of 90{sup o} within 15 s. For reconstruction, filtered back projection on a graphics processor unit was used. It reconstructed 100 projections acquired to a 512 x 512 x 512 volume within 6 s. Results: The resolution in the Catphan phantom (CTP528 high-resolution module) was 3 lines/cm. The spatial accuracy was within 2-3 mm. The diameters of different tumor shapes in the thorax phantom were determined within an accuracy of 1.6 mm. The signal-to-noise ratio was 68% less than that with a 180{sup o}-kV scan. The dose generated to acquire the MV frames accumulated to 82.5 mGy, and the kV contribution was <6 mGy. Conclusion: The present results have shown that fast breath-hold, on-line volume imaging with a linear accelerator using simultaneous kV-MV cone-beam computed tomography is promising and can potentially be used for image-guided radiotherapy for lung cancer patients in the near future.

  2. Effect of object location on the density measurement in cone-beam computed tomography versus multislice computed tomography.

    PubMed

    Eskandarloo, Amir; Abdinian, Mehrdad; Salemi, Fatemeh; Hashemzadeh, Zahra; Safaei, Mehran

    2012-12-01

    Bone density measurement in a radiographic view is a valuable method for evaluating the density of bone quality before performing some dental procedures such as, dental implant placements. It seems that Cone-Beam Computed Tomography (CBCT) can be used as a diagnostic tool for evaluating the density of the bone, prior to any treatment, as the reported radiation dose in this method is minimal. The aim of this study is to investigate the effect of object location on the density measurement in CBCT versus Multislice computed tomography (CT). In an experimental study, three samples with similar dimensions, but different compositions, different densities (Polyethylene, Polyamide, Polyvinyl Chloride), and three bone pieces of different parts of the mandibular bone were imaged in three different positions by CBCT and Multislice CT sets. The average density value was computed for each sample in each position. Then the data obtained from each CBCT was converted to a Hounsfield unit and evaluated using a single variable T analysis. A P value <0.05 was considered to be significant. The density in a Multislice CT is stable in the form of a Hounsfield Number, but this density is variable in the images acquired through CBCT, and the change in the position results in significant changes in the density. In this study, a statistically significant difference (P value = 0.000) has been observed for the position of the sample and its density in CBCT in comparison to Multislice CT. Density values in CBCT are not real because they are affected by the position of the object in the machine.

  3. Effect of object location on the density measurement in cone-beam computed tomography versus multislice computed tomography

    PubMed Central

    Eskandarloo, Amir; Abdinian, Mehrdad; Salemi, Fatemeh; Hashemzadeh, Zahra; Safaei, Mehran

    2012-01-01

    Background: Bone density measurement in a radiographic view is a valuable method for evaluating the density of bone quality before performing some dental procedures such as, dental implant placements. It seems that Cone-Beam Computed Tomography (CBCT) can be used as a diagnostic tool for evaluating the density of the bone, prior to any treatment, as the reported radiation dose in this method is minimal. The aim of this study is to investigate the effect of object location on the density measurement in CBCT versus Multislice computed tomography (CT). Materials and Methods: In an experimental study, three samples with similar dimensions, but different compositions, different densities (Polyethylene, Polyamide, Polyvinyl Chloride), and three bone pieces of different parts of the mandibular bone were imaged in three different positions by CBCT and Multislice CT sets. The average density value was computed for each sample in each position. Then the data obtained from each CBCT was converted to a Hounsfield unit and evaluated using a single variable T analysis. A P value <0.05 was considered to be significant. Results: The density in a Multislice CT is stable in the form of a Hounsfield Number, but this density is variable in the images acquired through CBCT, and the change in the position results in significant changes in the density. In this study, a statistically significant difference (P value = 0.000) has been observed for the position of the sample and its density in CBCT in comparison to Multislice CT. Conclusions: Density values in CBCT are not real because they are affected by the position of the object in the machine. PMID:23814567

  4. Importance of cone beam computed tomography for diagnosis of calcifying cystic odontogenic tumour associated to odontoma. Report of a case.

    PubMed

    Marques, Yonara-Maria-Freire-Soares; Botelho, Tessa-de Lucena; Xavier, Flávia-Caló-de Aquino; Rangel, Andrea-Leão; Rege, Inara-Carneiro-Costa; Mantesso, Andrea

    2010-05-01

    The calcifying cystic odontogenic tumour (CCOT) is a rare benign cystic neoplasm not infrequently associated with odontoma. This report documents a case of CCOT associated with compound odontoma arising in the anterior maxilla in a 25-year-old woman. Conventional radiographs showed a large calcified mass with poorly visualized radiolucent margins. The extent and condition of the internal structure of the CCOT associated with odontoma was able to be determined based on radiographic findings from cone beam computed tomography. This advanced image technique proved to be extremely useful in the radiographic assessment of this particular neoplasm of the jawbones.

  5. Cone Beam Computed Tomography Heralding New Vistas in Appropriate Diagnosis and Efficient Management of Incidentally Found Impacted Mesiodens.

    PubMed

    Sane, Vikrant Dilip; Chandan, Sanjay; Patil, Sujay; Patil, Krishna

    2017-03-01

    As dentistry continues to go "digital," the field has seen a phenomenal increase in the use of digital imaging in dental practice. Complex impacted mesiodens present potential treatment complications and sometimes possible patient morbidity. Objectives of diagnostic imaging are to aid in diagnosis, decision making, and enhance treatment outcomes. As cases become more complex, sophisticated multiplane imaging methods allowing for a three-dimensional view are more likely to meet these objectives as opposed to traditional two-dimensional radiography. The clinical report elucidates with the help of an illustrative patient how cone beam computed tomography imaging can assist the surgeon during surgical treatment planning, risk assessment, and treatment outcomes of impacted mesiodens.

  6. Cone beam computed tomography for the nasal cavity and paranasal sinuses.

    PubMed

    Parks, Edwin T

    2014-07-01

    The paranasal sinuses are 4 paired airspaces that border the nasal cavity. Dental professionals are most familiar with the maxillary sinuses as viewed in 2-D imaging (eg, periapical, panoramic projections). With increasing implementation of 3-D imaging, specifically cone beam CT, there is a high probability that much or all of the paranasal sinuses and nasal cavity will be captured in a scan. It is incumbent on practitioners to be familiar with all the structures contained within a scanned area. The purpose of this article is to provide an overview of the anatomy of the nasal cavity as well as common anatomic variants and pathologic entities. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Diagnosis of simulated condylar bone defects using panoramic radiography, spiral tomography and cone-beam computed tomography: A comparison study

    PubMed Central

    Salemi, Fatemeh; Shokri, Abbas; Baharvand, Maryam

    2015-01-01

    Objectives: Radiographic examination is one of the most important parts of the clinical assessment routine for temporomandibular disorders. The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography(CBCT) with panoramic radiography and spiral computed tomography for the detection of the simulated mandibular condyle bone lesions. Study Design: The sample consisted of 10 TMJs from 5 dried human skulls. Simulated erosive and osteophytic lesions were created in 3 different sizes using round diamond bur and bone chips, respectively. Panoramic radiography, spiral tomography and cone-beam computed tomography were used in defect detection. Data were statistically analyzed with the Mann-Whitney test. The reliability and degrees of agreement between two observers were also determined by the mean of Cohen’s Kappa analysis. Results: CBCT had a statistically significant superiority than other studied techniques in detection of both erosive and osteophytic lesions with different sizes. There were significant differences between tomography and panoramic in correct detection of both erosive and osteophytic lesions with 1mm and 1.5 mm in size. However, there were no significant differences between Tomography and Panoramic in correct detection of both erosive and osteophytic lesions with 0.5 mm in size. Conclusions: CBCT images provide a greater diagnostic accuracy than spiral tomography and panoramic radiography in the detection of condylar bone erosions and osteophytes. Key words:Bone defect, Condyle, CBCT, Panoramic, radiography. PMID:25810839

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

    SciTech Connect

    Gayou, Olivier Colonias, Athanasios

    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

  9. Detection of root perforations using conventional and digital intraoral radiography, multidetector computed tomography and cone beam computed tomography

    PubMed Central

    Eskandarloo, Amir; Noruzi-Gangachin, Maruf; Khajeh, Samira

    2015-01-01

    Objectives This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. Materials and Methods Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. Results The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. Conclusions If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended. PMID:25671214

  10. Autotransplantation of an immature premolar, with the aid of cone beam CT and computer-aided prototyping: a case report.

    PubMed

    Keightley, Alexander J; Cross, David L; McKerlie, Robert A; Brocklebank, Laetitia

    2010-04-01

    Autotransplantation of immature teeth has good survival rates, and has benefits over ossointegrated implants in the growing child, but is very technique sensitive. Spiral CT imaging has been previously used in adult patients to enable computer-aided prototyping to produce a surgical template of the donor tooth, further increasing success rates. The case presented describes management of a 9-year-old girl with the combination of hypodontia affecting the upper lateral incisors as well as a severely ectopic maxillary canine. Cone beam CT was used in combination with computer-aided prototyping to produce a surgical template of an immature mandibular second premolar. The surgical template was used to prepare the transplant site before the donor tooth was extracted, greatly reducing the time from extraction to implantation. By 6 months posttransplant the tooth was clinically sound, and continued root development and laying down of dentine was visible radiographically. This paper demonstrates the use of a novel technique to aid the surgical procedure of autotransplantation of immature premolar teeth. The use of autotransplantation in this case allowed the difficult situation of two missing units in the upper left quadrant to be reduced to one unit, while retaining symmetry in the upper arch. Compared to previous studies, the use of cone beam CT to create a 3D prototype reduced radiation dose compared to spiral CT and drastically reduced the extra-oral time of the donor tooth from extraction to transplantation.

  11. The importance of cone-beam computed tomography in the management of endodontic problems: a review of the literature.

    PubMed

    Venskutonis, Tadas; Plotino, Gianluca; Juodzbalys, Gintaras; Mickevičienė, Lina

    2014-12-01

    To obtain essential information in clinical endodontics, cone-beam computed tomographic (CBCT) imaging can be used in all phases of treatment including diagnosis, treatment planning, during the treatment phase, and through post-treatment assessment and follow-up. The purpose of this article was to review the use of CBCT imaging in the diagnosis, treatment planning, and assessing the outcome of endodontic complications. Literature was selected through a search of PubMed electronic databases for the following keywords: tooth root injuries, tooth root radiography, tooth root perforation, tomography, cone-beam computed tomography, endodontic complications, tooth root internal/external resorption, root fractures, and broken instruments. The research was restricted to articles published in English. One hundred twelve articles met the inclusion criteria and were included in this review. Currently, intraoral radiography is the imaging technique of choice for the management of endodontic disease, but CBCT imaging appears to have a superior validity and reliability in the management of endodontic diagnosis and complications. Endodontic cases should be judged individually, and CBCT imaging should be considered in situations in which information from conventional imaging systems may not yield an adequate amount of information to allow the appropriate management of endodontic problems. CBCT imaging has the potential to become the first choice for endodontic treatment planning and outcome assessment, especially when new scanners with lower radiation doses will be available. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. In vitro comparison of cone beam computed tomography with different voxel sizes for detection of simulated external root resorption.

    PubMed

    Neves, Frederico S; de Freitas, Deborah Q; Campos, Paulo S F; de Almeida, Solange M; Haiter-Neto, Francisco

    2012-09-01

    The present study compared the efficacy of cone beam computed tomography using different voxel sizes in the diagnosis of simulated external root resorption. The presence or absence of simulated defects on buccal, mesial and distal root surfaces of 20 premolars was evaluated. The defects were small (0.26 mm in diameter and 0.08 mm deep), medium (0.62 mm in diameter and 0.19 mm deep) and large (1.05 mm in diameter and 0.24 mm deep), equally distributed on each root surface. Images were obtained using Classic i-CAT cone beam computed tomography with different voxel sizes: 0.12, 0.20, 0.25 and 0.30 mm. Five oral radiologists evaluated the images. Accuracy, sensitivity, specificity, positive and negative predictive values were determined. The sensitivity decreased and specificity increased as voxel size increased. Accuracy values were the highest for the smallest voxel size (0.12 mm). The results for voxel sizes 0.20 mm and 0.25 mm were similar. Positive and negative predictive values were similar in all protocols, except with 0.30 mm, in which they were the lowest. In conclusion, external root resorption was more easily diagnosed when a smaller voxel size was used.

  13. Spontaneous healing responses detected by cone-beam computed tomography of horizontal root fractures: a report of two cases.

    PubMed

    Fagundes, Dyana Dos Santos; de Mendonça, Isabela Lima; de Albuquerque, Maria Tereza Pedrosa; Inojosa, Inês de Fátima de Azevedo Jacinto

    2014-12-01

    Horizontal root fractures (HRF) usually affect the anterior teeth as a result of trauma, and generally heal spontaneously, depending on the vitality of the pulp. Diagnosis based on clinical findings, sensitivity tests, and radiographic examination is important to determine the presence of a root fracture and to prevent a root fracture from passing unnoticed. Cone-beam computed tomography (CBCT) has been used successfully for diagnosis and prognosis imaging of root fractures and has proved to be superior to other radiographic methods. This study reports two cases of dental trauma caused by a collision and a sports accident. The patients suffered horizontal root fractures in the maxillary left central incisor and in the mandibular left central incisor. The diagnosis of root fracture was confirmed by cone-beam computed tomography (CBCT) images, which also demonstrated spontaneous healing of the fracture line. The repair occurred by interposition of connective tissue in the former case and by interposition of bone and connective tissue in the latter case. The final diagnoses of both cases were based on CBCT images, indicating the importance of a CBCT examination to reach a firm diagnosis and to follow the healing process of root fracture cases, avoiding unnecessary radical endodontic treatment.

  14. Differential diagnosis of endodontic-related inferior alveolar nerve paraesthesia with cone beam computed tomography: a case report.

    PubMed

    Gambarini, G; Plotino, G; Grande, N M; Testarelli, L; Prencipe, M; Messineo, D; Fratini, L; D'Ambrosio, F

    2011-02-01

    To discuss the use of cone-beam computed tomography (CBCT) in the differential diagnosis of a case of labiomandibular paraesthesia caused by extrusion of endodontic sealer into the mandibular canal. A 59-year-old woman suffering from a paraesthesia on the left posterior mandible and numbness on the left side of the lower lip was referred to an endodontic specialist 1 month after multiple root canal treatments. A panoramic radiograph revealed the presence of extruded root filling material beyond the apex of the mesial root of the mandibular left second molar and also beyond the apex of the first premolar. A cone beam computed tomography examination was undertaken, which confirmed the presence of radiopaque root canal filling material in the periapical area of the second molar, and revealed that the material was inside the mandibular canal. No extruded filling material was found inside the mental foramen beyond the apex of the first premolar tooth. Small field of view CBCT (where possible) can be considered an effective radiographic diagnostic device when endodontic-related inferior alveolar nerve or mental foramen paraesthesia are suspected. CBCT is able to provide detailed three-dimensional images of the tooth, the root canal system and the surrounding tissue. © 2010 International Endodontic Journal.

  15. Root and canal morphology of maxillary second molars by cone-beam computed tomography in a native Chinese population.

    PubMed

    Wu, Daming; Zhang, Guangdong; Liang, Ruizhen; Zhou, Guangchao; Wu, Younong; Sun, Chao; Fan, Wei

    2017-04-01

    Objective To evaluate the root and root canal morphology of the maxillary second molars (MSMs) in a native Chinese population by cone-beam computed tomography. Methods Cone-beam computed tomography images of 2412 MSMs from 1294 Chinese patients were analyzed to determine the number and morphology of the roots, the root canal morphology, the bilateral symmetry, and the correlations of these parameters with sex and age. Results The percentage of fused roots increased with age, while the percentage of fused roots in women was higher than that in men. The percentage of second mesiobuccal (MB2) canals in MSMs with three separate roots was higher in men than women. Patients aged 31 to 40 years showed a higher prevalence of MB2 canals, while those aged ≥51 years showed the lowest prevalence of MB2 canals among both men and women. There was a significant difference in bilateral symmetry of MSMs between men and women. Conclusion Root fusion of MSMs increased with age, while the root canal morphology was more complex in patients of intermediate ages.

  16. Orthodontic decompensation in skeletal Class III malocclusion: redefining the amount of movement assessed by Cone-Beam Computed Tomography

    PubMed Central

    Cappellozza, José Antonio Zuega; Guedes, Fabio Pinto; Nary, Hugo; Capelozza, Leopoldino; Cardoso, Mauricio de Almeida

    2015-01-01

    Introduction: Cone-Beam Computed Tomography (CBCT) is essential for tridimensional planning of orthognathic surgery, as it allows visualization and evaluation of bone structures and mineralized tissues. Tomographic slices allow evaluation of tooth inclination and individualization of movement performed during preoperative decompensation. The aim of this paper was to assess maxillary and mandibular incisors inclination pre and post orthodontic decompensation in skeletal Class III malocclusion. Methods: The study was conducted on six individuals with skeletal Class III malocclusion, surgically treated, who had Cone-Beam Computed Tomographic scans obtained before and after orthodontic decompensation. On multiplanar reconstruction view, tomographic slices (axial, coronal and sagittal) were obtained on the long axis of each incisor. The sagittal slice was used for measurement taking, whereas the references used to assess tooth inclination were the long axis of maxillary teeth in relation to the palatal plane and the long axis of mandibular teeth in relation to the mandibular plane. Results: There was significant variation in the inclination of incisors before and after orthodontic decompensation. This change was of greater magnitude in the mandibular arch, evidencing that natural compensation is more effective in this arch, thereby requiring more intensive decompensation. Conclusion: When routinely performed, the protocols of decompensation treatment in surgical individuals often result in intensive movements, which should be reevaluated, since the extent of movement predisposes to reduction in bone attachment levels and root length. PMID:26560818

  17. Evaluation of dose from kV cone-beam computed tomography during radiotherapy: a comparison of methodologies

    NASA Astrophysics Data System (ADS)

    Buckley, J.; Wilkinson, D.; Malaroda, A.; Metcalfe, P.

    2017-01-01

    Three alternative methodologies to the Computed-Tomography Dose Index for the evaluation of Cone-Beam Computed Tomography dose are compared, the Cone-Beam Dose Index, IAEA Human Health Report No. 5 recommended methodology and the AAPM Task Group 111 recommended methodology. The protocols were evaluated for Pelvis and Thorax scan modes on Varian® On-Board Imager and Truebeam kV XI imaging systems. The weighted planar average dose was highest for the AAPM methodology across all scans, with the CBDI being the second highest overall. A 17.96% and 1.14% decrease from the TG-111 protocol to the IAEA and CBDI protocols for the Pelvis mode and 18.15% and 13.10% decrease for the Thorax mode were observed for the XI system. For the OBI system, the variation was 16.46% and 7.14% for Pelvis mode and 15.93% to the CBDI protocol in Thorax mode respectively.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Evaluating the four-dimensional cone beam computed tomography with varying gantry rotation speed.

    PubMed

    Yoganathan, S A; Maria Das, K J; Mohamed Ali, Shajahan; Agarwal, Arpita; Mishra, Surendra P; Kumar, Shaleen

    2016-01-01

    The purpose of this work was to evaluate the four-dimensional cone beam CT (4DCBCT) imaging with different gantry rotation speed. All the 4DCBCT image acquisitions were carried out in Elekta XVI Symmetry™ system (Elekta AB, Stockholm, Sweden). A dynamic thorax phantom with tumour mimicking inserts of diameter 1, 2 and 3 cm was programmed to simulate the respiratory motion (4 s) of the target. 4DCBCT images were acquired with different gantry rotation speeds (36°, 50°, 75°, 100°, 150° and 200° min(-1)). Owing to the technical limitation of 4DCBCT system, average cone beam CT (CBCT) images derived from the 10 phases of 4DCBCT were used for the internal target volume (ITV) contouring. ITVs obtained from average CBCT were compared with the four-dimensional CT (4DCT). In addition, the image quality of 4DCBCT was also evaluated for various gantry rotation speeds using Catphan(®) 600 (The Phantom Laboratory Inc., Salem, NY). Compared to 4DCT, the average CBCT underestimated the ITV. The ITV deviation increased with increasing gantry speed (-10.8% vs -17.8% for 36° and 200° min(-1) in 3-cm target) and decreasing target size (-17.8% vs -26.8% for target diameter 3 and 1 cm in 200° min(-1)). Similarly, the image quality indicators such as spatial resolution, contrast-to-noise ratio and uniformity also degraded with increasing gantry rotation speed. The impact of gantry rotation speed has to be considered when using 4DCBCT for ITV definition. The phantom study demonstrated that 4DCBCT with slow gantry rotation showed better image quality and less ITV deviation. Usually, the gantry rotation period of Elekta 4DCBCT system is kept constant at 4 min (50° min(-1)) for acquisition, and any attempt of decreasing/increasing the acquisition duration requires careful investigation. In this study, the 4DCBCT images with different gantry rotation speed were evaluated.

  20. Evaluating the four-dimensional cone beam computed tomography with varying gantry rotation speed

    PubMed Central

    Maria Das, K J; Mohamed Ali, Shajahan; Agarwal, Arpita; Mishra, Surendra P; Kumar, Shaleen

    2016-01-01

    Objective: The purpose of this work was to evaluate the four-dimensional cone beam CT (4DCBCT) imaging with different gantry rotation speed. Methods: All the 4DCBCT image acquisitions were carried out in Elekta XVI Symmetry™ system (Elekta AB, Stockholm, Sweden). A dynamic thorax phantom with tumour mimicking inserts of diameter 1, 2 and 3 cm was programmed to simulate the respiratory motion (4 s) of the target. 4DCBCT images were acquired with different gantry rotation speeds (36°, 50°, 75°, 100°, 150° and 200° min−1). Owing to the technical limitation of 4DCBCT system, average cone beam CT (CBCT) images derived from the 10 phases of 4DCBCT were used for the internal target volume (ITV) contouring. ITVs obtained from average CBCT were compared with the four-dimensional CT (4DCT). In addition, the image quality of 4DCBCT was also evaluated for various gantry rotation speeds using Catphan® 600 (The Phantom Laboratory Inc., Salem, NY). Results: Compared to 4DCT, the average CBCT underestimated the ITV. The ITV deviation increased with increasing gantry speed (−10.8% vs −17.8% for 36° and 200° min−1 in 3-cm target) and decreasing target size (−17.8% vs −26.8% for target diameter 3 and 1 cm in 200° min−1). Similarly, the image quality indicators such as spatial resolution, contrast-to-noise ratio and uniformity also degraded with increasing gantry rotation speed. Conclusion: The impact of gantry rotation speed has to be considered when using 4DCBCT for ITV definition. The phantom study demonstrated that 4DCBCT with slow gantry rotation showed better image quality and less ITV deviation. Advances in knowledge: Usually, the gantry rotation period of Elekta 4DCBCT system is kept constant at 4 min (50° min−1) for acquisition, and any attempt of decreasing/increasing the acquisition duration requires careful investigation. In this study, the 4DCBCT images with different gantry rotation speed were evaluated. PMID:26916281

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

    PubMed

    Yang, Ching-Ching

    2016-01-01

    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.

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

    PubMed Central

    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

  3. Deriving Hounsfield units using grey levels in cone beam computed tomography

    PubMed Central

    Mah, P; Reeves, T E; McDavid, W D

    2010-01-01

    Objectives An in vitro study was performed to investigate the relationship between grey levels in dental cone beam CT (CBCT) and Hounsfield units (HU) in CBCT scanners. Methods A phantom containing 8 different materials of known composition and density was imaged with 11 different dental CBCT scanners and 2 medical CT scanners. The phantom was scanned under three conditions: phantom alone and phantom in a small and large water container. The reconstructed data were exported as Digital Imaging and Communications in Medicine (DICOM) and analysed with On Demand 3D® by Cybermed, Seoul, Korea. The relationship between grey levels and linear attenuation coefficients was investigated. Results It was demonstrated that a linear relationship between the grey levels and the attenuation coefficients of each of the materials exists at some “effective” energy. From the linear regression equation of the reference materials, attenuation coefficients were obtained for each of the materials and CT numbers in HU were derived using the standard equation. Conclusions HU can be derived from the grey levels in dental CBCT scanners using linear attenuation coefficients as an intermediate step. PMID:20729181

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

    PubMed Central

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

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations. PMID:21159912

  5. Accuracy of linear measurement in the Galileos cone beam computed tomography under simulated clinical conditions

    PubMed Central

    Ganguly, R; Ruprecht, A; Vincent, S; Hellstein, J; Timmons, S; Qian, F

    2011-01-01

    Objectives The aim of this study was to determine the geometric accuracy of cone beam CT (CBCT)-based linear measurements of bone height obtained with the Galileos CBCT (Sirona Dental Systems Inc., Bensheim, Hessen, Germany) in the presence of soft tissues. Methods Six embalmed cadaver heads were imaged with the Galileos CBCT unit subsequent to placement of radiopaque fiduciary markers over the buccal and lingual cortical plates. Electronic linear measurements of bone height were obtained using the Sirona software. Physical measurements were obtained with digital calipers at the same location. This distance was compared on all six specimens bilaterally to determine accuracy of the image measurements. Results The findings showed no statistically significant difference between the imaging and physical measurements (P > 0.05) as determined by a paired sample t-test. The intraclass correlation was used to measure the intrarater reliability of repeated measures and there was no statistically significant difference between measurements performed at the same location (P > 0.05). Conclusions The Galileos CBCT image-based linear measurement between anatomical structures within the mandible in the presence of soft tissues is sufficiently accurate for clinical use. PMID:21697155

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

    PubMed

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

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations.

  7. Usefulness of cone beam computed tomography in temporomandibular joints with soft tissue pathology

    PubMed Central

    Alkhader, M; Kuribayashi, A; Ohbayashi, N; Nakamura, S; Kurabayashi, T

    2010-01-01

    Objective The aim of the study was to evaluate the usefulness of cone beam CT (CBCT) in temporomandibular joints (TMJs) with soft tissue pathology. Methods 106 TMJs of 55 patients with temporomandibular disorder (TMD) were examined by MRI and CBCT. MR images were used for the evaluation of disc displacement, disc deformity, joint effusion and obscurity of temporal posterior attachment (TPA). CBCT images were evaluated for the presence or absence of osseous abnormalities. The χ2 test was used to analyse the association between MRI and CBCT findings. Results MRI of 106 TMJs revealed disc displacement, disc deformity, joint effusion and obscurity of the TPA in 68, 73, 28 and 27 joints, respectively. Of the 68 TMJs with disc displacement, anterior disc displacement without reduction (ADDWR) was seen most frequently (47/68). CBCT imaging found 65 TMJs were characterized by the presence of osseous abnormalities and were significantly associated with disc deformity and ADDWR (P < 0.05). There was no statistically significant association between the presence of joint effusion and obscurity of TPA and TMJ osseous abnormalities. Conclusions TMD patients with confirmed ADDWR or disc deformity on MRI are at risk of having osseous abnormalities in the TMJ and further examination with CBCT is recommended. PMID:20729183

  8. The usage of digital radiography and cone beam computed tomography among Turkish dentists

    PubMed Central

    Dölekoğlu, S; Fişekçioğlu, E; İlgüy, M; İlgüy, D

    2011-01-01

    Objectives The aim of this study was to determine the prevalence of the use of digital radiography and report how it was used by Turkish dentists. Methods The survey was based on 383 dentists who were present at the sixteenth International Congress organized by the Turkish Dental Association. A questionnaire which consisted of 19 questions was given to the dentists who participated in the study. Data were assessed according to frequency distribution and the χ2 test was used to determine the significance of differences between two independent groups. Results 376 questionnaires were analysed. The mean age of the dentists who participated in the study was 37.14 ± 9.6 years (range: 20–63 years). The distribution of the dentists according to the 7 regions of Turkey were: Marmara 58%, Aegean 13% and Mediterranean 10%, Central Anatolia 8%, Black Sea 7%, Southeastern Anatolia 3%, Eastern Anatolia 1%. 124 dentists (33%) said they did not work with digital radiography. 95 dentists indicated that they did not use digital radiography owing to cost (60%). 252 dentists (67%) said they used digital radiography. 40% of the participants noted that the repetition of periapical radiographs was due to digital radiography. 166 dentists (55.9%) and 79.1% academicians had knowledge about cone beam CT (CBCT). Conclusion Digital radiography users are increasing in Turkey and levels of knowledge of CBCT and awareness of radiation safety has also increased. PMID:21831978

  9. The usage of digital radiography and cone beam computed tomography among Turkish dentists.

    PubMed

    Dölekoğlu, Semanur; Fişekçioğlu, E; İlgüy, M; İlgüy, D

    2011-09-01

    The aim of this study was to determine the prevalence of the use of digital radiography and report how it was used by Turkish dentists. The survey was based on 383 dentists who were present at the sixteenth International Congress organized by the Turkish Dental Association. A questionnaire which consisted of 19 questions was given to the dentists who participated in the study. Data were assessed according to frequency distribution and the χ(2) test was used to determine the significance of differences between two independent groups. 376 questionnaires were analysed. The mean age of the dentists who participated in the study was 37.14 ± 9.6 years (range: 20-63 years). The distribution of the dentists according to the 7 regions of Turkey were: Marmara 58%, Aegean 13% and Mediterranean 10%, Central Anatolia 8%, Black Sea 7%, Southeastern Anatolia 3%, Eastern Anatolia 1%. 124 dentists (33%) said they did not work with digital radiography. 95 dentists indicated that they did not use digital radiography owing to cost (60%). 252 dentists (67%) said they used digital radiography. 40% of the participants noted that the repetition of periapical radiographs was due to digital radiography. 166 dentists (55.9%) and 79.1% academicians had knowledge about cone beam CT (CBCT). Digital radiography users are increasing in Turkey and levels of knowledge of CBCT and awareness of radiation safety has also increased.

  10. The Use of Cone Beam Computed Tomography in Assessing the Insertion of Bone Conduction Hearing Implants.

    PubMed

    Calon, Tim George Ate; Johansson, Martin Lars; van den Burg, Elske Larissa; Janssen, Anna Maria Louisa; van Hoof, Marc; Stokroos, Robert Jan

    2017-01-01

    This study aimed to compare postoperative cone beam CT (CBCT) imaging to implant stability quotient (ISQ) measurement and direct caliper measurements as a suitable technique to assess bone conduction hearing implant (BCHI) seating and insertion depth. In vitro, BCHIs were completely (n = 9) and partially inserted (n = 9) in bone blocks of different densities and subsequently scanned. Scans were processed using 3DSlicer 4.3.1 and Mathematica 10.3. ISQ measurements were obtained for all BCHIs mounted with different abutment lengths (9, 12, and 14 mm). CBCT imaging was performed for patients with a clinical indication. In vitro, 95% prediction intervals for partially inserted and completely inserted BCHIs were determined. ISQ values significantly decreased with partial insertion, low-density artificial bone, and longer abutment lengths. Evaluation of in vitro and in vivo 3D models allowed for assessment of insertion depth and inclination. CBCT imaging allows to study implant seating and insertion depth after BCHI surgery. This can be useful when visual confirmation is limited. It is possible to distinguish a partial BCHI insertion from a complete insertion in artificial bone blocks. This technique could prove to be a valuable research tool. In vitro, ISQ values for Ponto BCHIs relate to abutment length, insertion depth, and artificial bone density.

  11. Salivary calculus diagnosis with 3-dimensional cone-beam computed tomography.

    PubMed

    Dreiseidler, Timo; Ritter, Lutz; Rothamel, Daniel; Neugebauer, Jörg; Scheer, Martin; Mischkowski, Robert A

    2010-07-01

    The objective of this study was to evaluate cone-beam CT (CBCT) diagnoses of sialoliths in the major salivary glands. Twenty-nine CBCT images containing salivary calculi were retrospectively evaluated for image quality and artifact influence. Additionally, the reproducibility of calculus measurement and the differences between CBCT measurements and ultrasonography (US) and histomorphometry (HM) measurements were determined. Diagnostic sensitivity and specificity calculations were based on the observations of 3 masked clinicians, who reviewed a total of 58 CBCT volumes. Salivary calculi were sufficiently visualized in all patients. Metal artifacts were detected in images of 7 patients, and movement artifacts in 2. CBCT calculi measurements were highly reproducible, with mean differences of less than 350 microm. Mean CBCT measurements of calculi diameters differed from mean US measurements by approximately 500 microm and differed from mean HM measurements by approximately 1 mm. For calculus diagnoses, the mean sensitivity and specificity were both 98.85%. Although poor image qualities and artifacts can reduce diagnostic information, salivary calculi can be evaluated adequately with CBCT. CBCT measurements of calculi are highly reproducible and differ little from measurements made with US and HM. Diagnostic sensitivity and specificity levels with CBCT are as high as or higher than those obtained with other diagnostic methods. Because of its high diagnostic-information-to-radiation-dose ratio, CBCT is the preferable imaging modality for salivary calculus diagnosis. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  12. Presurgical Cone Beam Computed Tomography Bone Quality Evaluation for Predictable Immediate Implant Placement and Restoration in Esthetic Zone

    PubMed Central

    2017-01-01

    Despite numerous advantages over multislice computed tomography (MSCT), including a lower radiation dose to the patient, shorter acquisition times, affordable cost, and sometimes greater detail with isotropic voxels used in reconstruction, allowing precise measurements, cone beam computed tomography (CBCT) is still controversial regarding bone quality evaluation. This paper presents a brief review of the literature on accuracy and reliability of bone quality assessment with CBCT and a case report with step-by-step predictable treatment planning in esthetic zone, based on CBCT scans which enabled the clinician to evaluate, depending on bone volume and quality, whether immediate restoration with CAD-CAM manufactured temporary crown and flapless surgery may be a treatment option. PMID:28321342

  13. Cone-Beam Computed Tomography: Imaging Dose during CBCT Scan Acquisition and Accuracy of CBCT Based Dose Calculations

    NASA Astrophysics Data System (ADS)

    Giles, David Matthew

    Cone beam computed tomography (CBCT) is a recent development in radiotherapy for use in image guidance. Image guided radiotherapy using CBCT allows visualization of soft tissue targets and critical structures prior to treatment. Dose escalation is made possible by accurately localizing the target volume while reducing normal tissue toxicity. The kilovoltage x-rays of the cone beam imaging system contribute additional dose to the patient. In this study a 2D reference radiochromic film dosimetry method employing GAFCHROMIC(TM) model XR-QA film is used to measure point skin doses and dose profiles from the Elekta XVI CBCT system integrated onto the Synergy linac. The soft tissue contrast of the daily CBCT images makes adaptive radiotherapy possible in the clinic. In order to track dose to the patient or utilize on-line replanning for adaptive radiotherapy the CBCT images must be used to calculate dose. A Hounsfield unit calibration method for scatter correction is investigated for heterogeneity corrected dose calculation in CBCT images. Three Hounsfield unit to density calibration tables are used for each of four cases including patients and an anthropomorphic phantom, and the calculated dose from each is compared to results from the clinical standard fan beam CT. The dose from the scan acquisition is reported and the effect of scan geometry and total output of the x-ray tube on dose magnitude and distribution is shown. The ability to calculate dose with CBCT is shown to improve with the use of patient specific density tables for scatter correction, and for high beam energies the calculated dose agreement is within 1%.

  14. Dose and image quality of cone-beam computed tomography as compared with conventional multislice computed tomography in abdominal imaging.

    PubMed

    Schegerer, Alexander A; Lechel, Ursula; Ritter, Manuel; Weisser, Gerald; Fink, Christian; Brix, Gunnar

    2014-10-01

    Recent technical developments have facilitated the application of cone-beam computed tomography (CBCT) for interventional and intraoperative imaging. The aim of this study was to compare the radiation doses and image quality in CBCT with those of conventional multislice spiral computed tomography (MSCT) for abdominal and genitourinary imaging. Different CBCT and MSCT protocols for imaging soft tissues and hard-contrast objects at different dose levels were investigated in this study. Local skin and organ doses were measured with thermoluminescent dosimeters placed in an anthropomorphic phantom. Moreover, the contrast-to-noise ratio, the noise-power spectrum, and the high-contrast resolution derived from the modulation transfer function were determined in a phantom with the same absorption properties as those of anthropomorphic phantom. The effective dose of the examined abdominal/genitourinary CBCT protocols ranged between 0.35 mSv and 18.1 mSv. As compared with MSCT, the local skin dose of CBCT examinations could locally reach much higher doses up to 190 mGy. The effective dose necessary to realize the same contrast-to-noise ratio with CBCT and MSCT depended on the MSCT convolution kernel: the MSCT dose was smaller than the corresponding CBCT dose for a soft kernel but higher than that for a hard kernel. The noise-power spectrum of the CBCT images at tube voltages of 85/90 kV(p) is at least half of that of images measured at 103/115 kV(p) at any arbitrarily chosen spatial frequency. Although the pixel size and slice thickness of CBCT were half of those of the MSCT images, high-contrast resolution was inferior to the MSCT images reconstructed with a hard convolution kernel. As compared with MSCT using a medium-hard convolution kernel, CBCT produces images at medium noise levels and, simultaneously, medium spatial resolution at approximately the same dose. It is well suited for visualizing hard-contrast objects in the abdomen with relatively low image noise and

  15. Clinical Applicability of Cone-Beam Computed Tomography in Monitoring Seroma Volume Change During Breast Irradiation

    SciTech Connect

    Yang, Tzu-I; Minkema, Danny; Elkhuizen, Paula; Heemsbergen, Wilma; Mourik, Anke M. van; Vliet-Vroegindeweij, Corine van

    2010-09-01

    Purpose: To determine whether cone-beam CT (CBCT) is effective in monitoring seroma reduction during breast irradiation when compared with conventional CT. Patients and Methods: This study included 19 women with Stage T1-2 breast cancer treated with breast-conserving therapy. Each patient underwent two to four CT and multiple CBCT scans (mean, 8; range, 7-13 scans) at various time intervals during radiotherapy. Seroma were contoured by two observers on all scans and checked by one radiation oncologist. Seroma clarity was determined according to The British Columbia Cancer Agency Seroma Clarity Score scale, and conformity index (CI) of the two observers was evaluated. Correlations in seroma contours and seroma characteristics between CBCT and CT, as well as interobserver variation, were examined. Results: The mean differences in seroma volume between CT and CBCT (3%, p = 0.3) and between the two observers (6%, p = 0.2) were not statistically significant. Seroma clarity correlated significantly with CI for both CT and CBCT (p = 0.02 and p = 0.001, respectively), indicating the higher the seroma clarity score, the greater the CI between the observers. With seroma clarity 3 or higher for CT and CBCT, a high level of observer concordance was shown (all CI of these scans were {>=}50%). Conclusion: Volume discrepancy between CBCT and CT and between the two observers was not statistically significant. Seroma clarity influenced observers' ability to contour on CT or CBCT equally. Therefore, CBCT is a good clinical surrogate for CT in monitoring seroma reduction during breast radiotherapy, especially for patients with seroma clarity score 3 or higher.

  16. Accuracy assessment of the axial images obtained from cone beam computed tomography

    PubMed Central

    Panzarella, FK; Junqueira, JLC; Oliveira, LB; de Araújo, NS; Costa, C

    2011-01-01

    Objective The aim of this study was to evaluate accuracy of linear measurements assessed from axial tomograms and the influence of the use of different protocols in two cone beam CT (CBCT) units. Methods A cylinder object consisting of Nylon® (Day Brazil, Sao Paulo, Brazil) with radiopaque markers was radiographically examined applying different protocols from NewTom 3GTM (Quantitative Radiology s.r.l, Verona, Veneto, Italy) and i-CATTM (Imaging Sciences International, Hatfield, PA) units. Horizontal (A–B) and vertical (C–D) distances were assessed from axial tomograms and measured using a digital calliper that provided the gold standard for actual values. Results There were differences when considering acquisition protocols to each CBCT unit. Concerning all analysed protocols from i-CATTM and Newtom 3GTM, both A–B and C–D distances presented underestimated values. Measurements of the axial images obtained from NewTom 3GTM (6 inch 0.16 mm and 9 inch 0.25 mm) were similar to the ones obtained from i-CATTM (13 cm 20 s 0.3 mm, 13 cm 20 s 0.4 mm and 13 cm 40 s 0.25 mm). Conclusion The use of different protocols from CBCT machines influences linear measurements assessed from axial images. Linear distances were underestimated in both equipments. Our findings suggest that the best protocol for the i-CATTM is 13 cm 20 s 0.3 mm and for the NewTom 3GTM, the use of 6 inch or 9 inch is recommended. PMID:21831977

  17. A suggested technique for the application of the cone beam computed tomography periapical index

    PubMed Central

    Esposito, S; Cardaropoli, M; Cotti, E

    2011-01-01

    Objectives Cone beam CT (CBCT) produces undistorted three-dimensional (3D) images of the maxillofacial region with a radiation dosage lower than conventional CT. The periapical index score (PAI) is commonly used to follow up the lesions in the bone using periapical radiographs. Recently, a new PAI based on CBCT was introduced (CBCT-PAI). The aim of this technical report is to present a modified reproducible method to assess the CBCT-PAI. Methods CBCT was used to evaluate a periapical bone lesion observed in the area of tooth number 13 before treatment and 2 years after treatment. The modified CBCT-PAI was applied to both the examinations to measure the lesion. The dimensional analysis of the lesion was performed in each plane, assessing three fixed and reproducible dimensions: mesiodistal (M-D), buccolingual (B-L) and coronoapical (C-A). The images were evaluated by three mutually independent examiners. Data were collected and reported in a chart. The results were compared with each other and with the PAI score from the periapical radiographs. Results The three observers reported the same measurements of the lesion for each plane. The CBCT-PAI follow-up showed a reduction of the size of the lesion (5D vs 4D) but also an increase in the erosion of the buccal cortical plate. The comparison of CBCT-PAI with classic PAI showed the first method to be more precise. Conclusions This technical report shows how the CBCT-PAI can be applied to the CBCT exam of a periapical lesion in a reproducible way. PMID:22065800

  18. Fractal dimension evaluation of cone beam computed tomography in patients with bisphosphonate-associated osteonecrosis

    PubMed Central

    Torres, SR; Chen, CSK; Leroux, BG; Lee, PP; Hollender, LG; Schubert, MM

    2011-01-01

    Objectives The aim of this study was to (1) evaluate the fractal dimension (FD) in regions of the mandible on cone beam CT (CBCT) images of patients with bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) and (2) to select the most suitable region of interest (ROI) for further study on detection of bone alterations associated with bisphosphonates. Methods CBCT images of patients with BP-ONJ were included with matched controls. Values of FD were compared between groups. Selected ROIs were: ROI-1 — below the mandibular foramen; ROI-2 — above the mandibular foramen; ROI-3 — anterior to the mental foramen; ROI-4 — above the mandibular canal. The area of bone exposure was included as ROI-5. The results were analysed using generalized estimating equations and conditional logistic regression. Results There were 36 patients (67% female) with a mean age of 60.7 years. The mean FDs were: ROI-1 — 1.678 for controls and 1.673 for patients (P = 0.81); ROI-2 — 1.657 for controls and 1.653 for patients (P = 0.78); ROI-3 — 1.661 for controls and 1.684 for patients (P = 0.17); and ROI-4 — 1.670 for controls and 1.698 for patients (P = 0.03). The value of the FD in the area of exposed bone was the highest (1.729). The odds of being a BP-ONJ patient vs being a control was six times as high for individuals with a higher FD score at ROI-4, although the confidence interval was quite wide owing to the small sample size. Conclusion In this preliminary study, BP-ONJ patients had higher FD values than controls at regions close to the alveolar process. The results suggest that FD is a promising tool for detection of bone alterations associated with BP-ONJ. PMID:22065799

  19. Prostate Localization on Daily Cone-Beam Computed Tomography Images: Accuracy Assessment of Similarity Metrics

    SciTech Connect

    Kim, Jinkoo; Hammoud, Rabih; Pradhan, Deepak; Zhong Hualiang; Jin, Ryan Y.; Movsas, Benjamin; Chetty, Indrin J.

    2010-07-15

    Purpose: To evaluate different similarity metrics (SM) using natural calcifications and observation-based measures to determine the most accurate prostate and seminal vesicle localization on daily cone-beam CT (CBCT) images. Methods and Materials: CBCT images of 29 patients were retrospectively analyzed; 14 patients with prostate calcifications (calcification data set) and 15 patients without calcifications (no-calcification data set). Three groups of test registrations were performed. Test 1: 70 CT/CBCT pairs from calcification dataset were registered using 17 SMs (6,580 registrations) and compared using the calcification mismatch error as an endpoint. Test 2: Using the four best SMs from Test 1, 75 CT/CBCT pairs in the no-calcification data set were registered (300 registrations). Accuracy of contour overlays was ranked visually. Test 3: For the best SM from Tests 1 and 2, accuracy was estimated using 356 CT/CBCT registrations. Additionally, target expansion margins were investigated for generating registration regions of interest. Results: Test 1-Incremental sign correlation (ISC), gradient correlation (GC), gradient difference (GD), and normalized cross correlation (NCC) showed the smallest errors ({mu} {+-} {sigma}: 1.6 {+-} 0.9 {approx} 2.9 {+-} 2.1 mm). Test 2-Two of the three reviewers ranked GC higher. Test 3-Using GC, 96% of registrations showed <3-mm error when calcifications were filtered. Errors were left/right: 0.1 {+-} 0.5mm, anterior/posterior: 0.8 {+-} 1.0mm, and superior/inferior: 0.5 {+-} 1.1 mm. The existence of calcifications increased the success rate to 97%. Expansion margins of 4-10 mm were equally successful. Conclusion: Gradient-based SMs were most accurate. Estimated error was found to be <3 mm (1.1 mm SD) in 96% of the registrations. Results suggest that the contour expansion margin should be no less than 4 mm.

  20. A suggested technique for the application of the cone beam computed tomography periapical index.

    PubMed

    Esposito, S; Cardaropoli, M; Cotti, E

    2011-12-01

    Cone beam CT (CBCT) produces undistorted three-dimensional (3D) images of the maxillofacial region with a radiation dosage lower than conventional CT. The periapical index score (PAI) is commonly used to follow up the lesions in the bone using periapical radiographs. Recently, a new PAI based on CBCT was introduced (CBCT-PAI). The aim of this technical report is to present a modified reproducible method to assess the CBCT-PAI. CBCT was used to evaluate a periapical bone lesion observed in the area of tooth number 13 before treatment and 2 years after treatment. The modified CBCT-PAI was applied to both the examinations to measure the lesion. The dimensional analysis of the lesion was performed in each plane, assessing three fixed and reproducible dimensions: mesiodistal (M-D), buccolingual (B-L) and coronoapical (C-A). The images were evaluated by three mutually independent examiners. Data were collected and reported in a chart. The results were compared with each other and with the PAI score from the periapical radiographs. The three observers reported the same measurements of the lesion for each plane. The CBCT-PAI follow-up showed a reduction of the size of the lesion (5D vs 4D) but also an increase in the erosion of the buccal cortical plate. The comparison of CBCT-PAI with classic PAI showed the first method to be more precise. This technical report shows how the CBCT-PAI can be applied to the CBCT exam of a periapical lesion in a reproducible way.

  1. Age assessment in canine and premolar by cervical axial sections of cone-beam computed tomography.

    PubMed

    Nemsi, Hichem; Haj Salem, Nidhal; Bouanene, Ines; Ben Jomaa, Sami; Belhadj, Meriem; Mosrati, Mohamed Amin; Aissaoui, Abir; Ben Amor, Faten; Chadly, Ali

    2017-09-01

    Age estimation in adults is a challenge in both anthropological and forensic situations compared to sub-adults age estimation. The present study explored, for the first time, the cervical zone of single rooted teeth. The deposition of secondary dentin is responsible for a decrease in the volume of the dental pulp cavity with aging, and therefore is often used as an age indicator. The current study aimed at estimating the chronological age among adults by measuring the pulp/dentin area ratio (physiological ratio) by axial sections at cervical region of maxillary canine and mandibular second premolar. The sample consisted of 120 cone beam CT images of 120 Tunisians whose age ranged from 22 to 67, from the database of a private clinic of radiology. The first axial section of chosen teeth without enamel was selected. Linear regression models were derived for canine, premolar and for all variables to predict the age. They indicated that dentin deposition on canine and premolar have almost the same correlation with age (r=-0.838 and -0.837 respectively). The residual standard errors (RSE), when these regression equations applied for the entire sample, were ranged between 8.27, 8.29 and 7.06 for canine, premolar and for all variables respectively. Tested for younger ages (from 22 to 44years) the RSE decreased considerably and thus ranged between 4.32, 4.72 and 4.05. The outcomes of this study show that the physiological ratio is a useful variable for assessing age with a satisfying accuracy. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Flat panel detector-based cone beam computed tomography with a circle-plus-two-arcs data acquisition orbit: preliminary phantom study.

    PubMed

    Ning, Ruola; Tang, Xiangyang; Conover, David; Yu, Rongfeng

    2003-07-01

    Cone beam computed tomography (CBCT) has been investigated in the past two decades due to its potential advantages over a fan beam CT. These advantages include (a) great improvement in data acquisition efficiency, spatial resolution, and spatial resolution uniformity, (b) substantially better utilization of x-ray photons generated by the x-ray tube compared to a fan beam CT, and (c) significant advancement in clinical three-dimensional (3D) CT applications. However, most studies of CBCT in the past are focused on cone beam data acquisition theories and reconstruction algorithms. The recent development of x-ray flat panel detectors (FPD) has made CBCT imaging feasible and practical. This paper reports a newly built flat panel detector-based CBCT prototype scanner and presents the results of the preliminary evaluation of the prototype through a phantom study. The prototype consisted of an x-ray tube, a flat panel detector, a GE 8800 CT gantry, a patient table and a computer system. The prototype was constructed by modifying a GE 8800 CT gantry such that both a single-circle cone beam acquisition orbit and a circle-plus-two-arcs orbit can be achieved. With a circle-plus-two-arcs orbit, a complete set of cone beam projection data can be obtained, consisting of a set of circle projections and a set of arc projections. Using the prototype scanner, the set of circle projections were acquired by rotating the x-ray tube and the FPD together on the gantry, and the set of arc projections were obtained by tilting the gantry while the x-ray tube and detector were at the 12 and 6 o'clock positions, respectively. A filtered backprojection exact cone beam reconstruction algorithm based on a circle-plus-two-arcs orbit was used for cone beam reconstruction from both the circle and arc projections. The system was first characterized in terms of the linearity and dynamic range of the detector. Then the uniformity, spatial resolution and low contrast resolution were assessed using

  3. Cone beam computed topographic evaluation and endodontic management of a rare mandibular first molar with four distal canals.

    PubMed

    Sinha, Nidhi; Singh, Bijay; Langaliya, Akshay; Mirdha, Nitin; Huda, Irfanul; Jain, Ashwin

    2014-01-01

    Root canal system is complex to understand because of its unpredictable nature. It differs for different teeth and for the same teeth in different individuals. Successful endodontic therapy thus depends on the clinician's ability to anticipate and look for these variations. A mandibular first molar with six root canals represents a rare anatomical variant, particularly when four canals are found in distal root. This case report discusses successful nonsurgical endodontic management of two-root mandibular first molar with four distal canals and two mesial canals reported for the first time in Indian population. Cone beam computed tomography was used as a diagnostic method to confirm the position and presence of 4 root canals in the distal root.

  4. The role of cone beam computed tomography in the management of unfavourable fractures following sagittal split mandibular osteotomy.

    PubMed

    Lloyd, Timothy E; Drage, Nicholas A; Cronin, Andrew J

    2011-03-01

    Cone beam computed tomography (CBCT) has been at the forefront of recent technological advances within the maxillofacial region. CBCT is useful in the accurate assessment and planning of patients undergoing orthognathic surgery. We propose that it also has a role in the post-operative evaluation of a subgroup of patients who have suffered complications at the time of surgery. We present two cases where unfavourable splits occurred during a bilateral sagittal split osteotomy (BSSO) of the mandible. Both cases were investigated post-operatively with CBCT with the aim of identifying the potential cause of the unfavourable split and to establish accurate localization of the condyle in the glenoid fossa following intra-operative attempts at proximal segment control. CBCT should be considered for evaluation of the mandible following an unfavourable split where it is deemed that plain radiographs would not provide adequate information.

  5. Endodontic management of maxillary first molar with seven root canals diagnosed using Cone Beam Computed Tomography scanning.

    PubMed

    Raghavendra, Srinidhi Surya; Hindlekar, Ajit Narayan; Desai, Niranjan Nanasaheb; Vyavahare, Nishant Kishor; Napte, Bandu Devrao

    2014-07-01

    The main objective of root canal treatment is thorough cleaning and shaping of the entire pulp space and its complete filling with an inert filling material. A major cause of post-treatment disease is the inability to locate, debride or adequately fill all canals of the root canal system. The form, configuration, and number of root canals in the maxillary first molars have been discussed for more than half a century. Maxillary first molars commonly present with three roots and three canals, with a second mesiobuccal canal (MB2) also present. With the advent of improved magnification there are reports of multiple root canals in the maxillary first molars. Nonsurgical endodontic therapy of a left maxillary first molar with three roots and seven root canals was successfully performed under a dental operating microscope. The diagnosis of multiple root canals was confirmed with the help of Cone Beam Computed Tomography (CBCT) images.

  6. Cone Beam Computed Topographic Evaluation and Endodontic Management of a Rare Mandibular First Molar with Four Distal Canals

    PubMed Central

    Sinha, Nidhi; Singh, Bijay; Langaliya, Akshay; Mirdha, Nitin; Huda, Irfanul

    2014-01-01

    Root canal system is complex to understand because of its unpredictable nature. It differs for different teeth and for the same teeth in different individuals. Successful endodontic therapy thus depends on the clinician's ability to anticipate and look for these variations. A mandibular first molar with six root canals represents a rare anatomical variant, particularly when four canals are found in distal root. This case report discusses successful nonsurgical endodontic management of two-root mandibular first molar with four distal canals and two mesial canals reported for the first time in Indian population. Cone beam computed tomography was used as a diagnostic method to confirm the position and presence of 4 root canals in the distal root. PMID:25525525

  7. Three-dimensional analysis of craniofacial bones and soft tissues in obstructive sleep apnea using cone beam computed tomography.

    PubMed

    Bruwier, Annick; Poirrier, Robert; Albert, Adelin; Maes, Nathalie; Limme, Michel; Charavet, Carole; Milicevic, Mladen; Raskin, Sylvianne; Poirrier, Anne-Lise

    2016-12-01

    A total of 154 adult patients with sleep complaints underwent a polysomnography and a craniofacial cone beam computed tomography (CBCT). OSA was defined as an apnea and hypopnea index (AHI) or an oxygen desaturation index (ODI) ≥ 10. Soft tissues and craniofacial bones volumes were prospectively measured by CBCT and collected blindly from sleep polysomnography. Among the study patients, 127 (83%) suffered from OSA and 27 (17%) did not. OSA patients demonstrated a narrower maxillo-palatine core volume (11.7±3.2 vs 14.6±4.9cm(3)) even when adjusting for age, gender, height, neck circumference and body mass index. These upper airway measures provide a comprehensive analysis of bony structures and soft tissues, which can be involved in OSA.

  8. Use of cone beam computed tomography and a laser intraoral scanner in virtual dental implant surgery: part 1.

    PubMed

    Lee, Cameron Y S; Ganz, Scott D; Wong, Natalie; Suzuki, Jon B

    2012-08-01

    To describe a new procedure capable of coupling 2 data sets from cone beam computed tomography (CBCT) and an intraoral laser digital scanner to produce a stereolithographic model and surgical guide. Use of DICOM (digital imaging and communications in medicine) format data obtained from CBCT scan images merged with standard triangulation language (STL) file data obtained from digital impressions using an intraoral laser scanner. The 2 data sets were electronically sent to a 3-dimensional imaging and technology software company over the Internet to fabricate a stereolithographic model of the jaws and surgical guide without the use of stone or plaster models obtained from traditional dental impressions. STL file data are able to accurately fabricate a stereolithographic model and surgical guide for implant surgery.

  9. Dual energy approach for cone beam artifacts correction

    NASA Astrophysics Data System (ADS)

    Han, Chulhee; Choi, Shinkook; Lee, Changwoo; Baek, Jongduk

    2017-03-01

    Cone beam computed tomography systems generate 3D volumetric images, which provide further morphological information compared to radiography and tomosynthesis systems. However, reconstructed images by FDK algorithm contain cone beam artifacts when a cone angle is large. To reduce the cone beam artifacts, two-pass algorithm has been proposed. The two-pass algorithm considers the cone beam artifacts are mainly caused by high density materials, and proposes an effective method to estimate error images (i.e., cone beam artifacts images) by the high density materials. While this approach is simple and effective with a small cone angle (i.e., 5 - 7 degree), the correction performance is degraded as the cone angle increases. In this work, we propose a new method to reduce the cone beam artifacts using a dual energy technique. The basic idea of the proposed method is to estimate the error images generated by the high density materials more reliably. To do this, projection data of the high density materials are extracted from dual energy CT projection data using a material decomposition technique, and then reconstructed by iterative reconstruction using total-variation regularization. The reconstructed high density materials are used to estimate the error images from the original FDK images. The performance of the proposed method is compared with the two-pass algorithm using root mean square errors. The results show that the proposed method reduces the cone beam artifacts more effectively, especially with a large cone angle.

  10. Worldwide Prevalence of Mandibular Second Molar C-Shaped Morphologies Evaluated by Cone-Beam Computed Tomography.

    PubMed

    von Zuben, Murilo; Martins, Jorge N R; Berti, Luiza; Cassim, Imran; Flynn, Daniel; Gonzalez, Jose Antonio; Gu, Yongchun; Kottoor, Jojo; Monroe, Adam; Rosas Aguilar, Rubén; Marques, Miguel Seruca; Ginjeira, António

    2017-09-01

    The aim of this study was to evaluate and compare the C-shaped mandibular second molar prevalence in different regions around the world with the aid of cone-beam computed tomography technology. Nine field observers from 9 different geographic regions were calibrated. A total of 400 samples were collected in each region. The prevalence of C-shaped anatomy was calculated. The number of roots and the configuration of the C-shaped canals at 3 different axial levels were also evaluated. The z-test was used to analyze the difference between the means of each independent group. Intrarater reliability was also tested. A total of 3600 teeth from 2735 patients were included in this research; 499 teeth presented C-shaped root canal configuration, representing a global prevalence of 13.9%. China had a prevalence of 44.0%, which was significantly higher than any other region. The C-shape prevalence in women was 16.5%, which was significantly higher than the 10.4% prevalence found in men. No difference between sides (37 or 47) was evident in the global sample. Cone-beam computed tomography is a valuable tool to evaluate the C-shaped root canal configuration in vivo. In the present study, China presented the highest prevalence of C-shaped mandibular second molars when compared with other regions. Women exhibited a higher prevalence than men. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Three-dimensional longitudinal changes in craniofacial growth in untreated hemifacial microsomia patients with cone-beam computed tomography.

    PubMed

    Shibazaki-Yorozuya, Reiko; Yamada, Akira; Nagata, Satoru; Ueda, Kouichi; Miller, Arthur J; Maki, Koutaro

    2014-05-01

    The purpose of this study was to evaluate the concept that the affected and contralateral sides do not grow at the same rate in patients with hemifacial microsomia. Changes in the cranial base, maxilla, mandible, and occlusal plane were evaluated on 3-dimensional images from cone-beam computed tomography data in untreated patients. Six patients were classified as having mandibular Pruzansky/Kaban type I, IIA, or IIB hemifacial microsomia. Cone-beam computed tomography (MercuRay; Hitachi, Tokyo, Japan) scans were taken before orthodontic treatment during both growth and postpuberty periods. The cranial base as defined by the position of the mastoid process was in a different position between the affected and contralateral control sides. The nasomaxillary length or height was shorter on the affected side for all 6 patients with hemifacial microsomia regardless of its severity, and it grew less than on the contralateral control side in 5 of the 6 patients. The occlusal plane angle became more inclined in 4 of the 6 patients. The mandibular ramus was shorter on the affected side in all patients and grew less on the affected side in 5 of the 6 patients. The mandibular body grew slower, the same, or faster than on the control side. The cranial base, position of the condyle, lengths of the condyle and ramus, and positions of the gonial angle and condyle can vary between the affected and contralateral control sides of patients with hemifacial microsomia, with the ramus and nasomaxillary length usually growing slower than they grow on the control side. These results suggest that many factors affect the growth rate of the craniofacial region and, specifically, the mandible in patients with hemifacial microsomia. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  12. Accuracy and Reliability of a Novel Method for Fusion of Digital Dental Casts and Cone Beam Computed Tomography Scans

    PubMed Central

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

    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 scanned, impressions were taken from the plaster models and the impressions were also scanned. Linear measurements were performed on all three models, to assess accuracy and reproducibility. Besides that, matching of the scanned plaster models and scanned impressions was done, to assess the accuracy of the matching procedure. Results show that all measurement errors are smaller than 0.2 mm, and that 81% is smaller than 0.1 mm. Matching of the scanned plaster casts and scanned impressions show a mean error between the two surfaces of the upper arch of 0.14 mm and for the lower arch of 0.18 mm. The time needed for reconstructing the CBCT scans to a digital patient, where the impressions are integrated into the CBCT scan of the patient takes about 15 minutes, with little variance between patients. In conclusion, we can state that this new method is a reliable method to integrate digital dental casts into CBCT scans. As far as radiation exposure, soft tissue deformation and digital handling processes are concerned, it is a significant improvement compared to the previously published methods. PMID:23527111

  13. Replacing Heavily Damaged Teeth by Third Molar Autotransplantation With the Use of Cone-Beam Computed Tomography and Rapid Prototyping.

    PubMed

    Verweij, Jop P; Anssari Moin, David; Wismeijer, Daniel; van Merkesteyn, J P Richard

    2017-09-01

    This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Single vs Two-session Root Canal Treatment: A Preliminary Randomized Clinical Study using Cone Beam Computed Tomography.

    PubMed

    de Castro Rizzi-Maia, Claudia; Maia-Filho, Etevaldo M; Nelson-Filho, Paulo; Segato, Raquel Ab; de Queiroz, Alexandra M; Paula-Silva, Francisco Wg; da Silva Pereira, Sângela M; Borges, Alvaro H; da Silva, Léa Ab

    2016-07-01

    To compare root canal treatment of teeth with apical periodontitis (AP) in a single or two visits, using cone beam computed tomography (CBCT). Twenty-six pairs of teeth (13 patients) were assigned to two groups: Group single-session (GSS): Instrumentation and root canal filling in the same session; and group two-session (GTS): A calcium hydroxide intracanal medication (Calen(®) paste) was used for 14 days between two sessions. Cone beam computed tomography scans were obtained before and 12 months after treatment. The pre- and postoperative volume of the AP lesions was measured in mm(3). The percentages of volume reduction was compared using Student's t-test and the existence of significant difference between the groups for cases with ≤ 50% or > 50% lesion volume reduction was assessed by chi-squared test ratio likelihood test (α = 5%). The volume reduction was greater in GTS (79.25%) than GSS (68.35%), though without significant difference (p > 0.05). After 12 months, complete repair was not observed in any specimen. Lesion volume reduction > 50% was significantly greater with the use of an intracanal medication (p < 0.05). Twelve months posttreatment, CBCT did not show complete repair in any of the teeth, suggesting that this follow-up period is not sufficient for complete lesion regression. In both groups, similar AP lesion volume reduction was observed after 12 months, with a more advanced repair (> 50% volume reduction) in the teeth medicated with calcium hydroxide intracanal dressing. Calcium hydroxide intracanal dressing provided clinical evidence to indicate its use in teeth with apical periodontitis prior to definitive root canal filling.

  15. Cone-Beam Computed Tomography Analysis of the Nasopharyngeal Airway in Nonsyndromic Cleft Lip and Palate Subjects.

    PubMed

    Al-Fahdawi, Mahmood Abd; Farid, Mary Medhat; El-Fotouh, Mona Abou; El-Kassaby, Marwa Abdelwahab

    2017-03-01

      To assess the nasopharyngeal airway volume, cross-sectional area, and depth in previously repaired nonsyndromic unilateral cleft lip and palate versus bilateral cleft lip and palate patients compared with noncleft controls using cone-beam computed tomography with the ultimate goal of finding whether cleft lip and palate patients are more liable to nasopharyngeal airway obstruction.   A retrospective analysis comparing bilateral cleft lip and palate, unilateral cleft lip and palate, and control subjects. Significance at P ≤ .05.   Cleft Care Center and the outpatient clinic that are both affiliated with our faculty.   Cone-beam computed tomography data were selected of 58 individuals aged 9 to 12 years: 14 with bilateral cleft lip and palate and 20 with unilateral cleft lip and palate as well as 24 age- and gender-matched noncleft controls.   Volume, depth, and cross-sectional area of nasopharyngeal airway were measured.   Patients with bilateral cleft lip and palate showed significantly larger nasopharyngeal airway volume than controls and patients with unilateral cleft lip and palate (P < .001). Patients with bilateral cleft lip and palate showed significantly larger cross-sectional area than those with unilateral cleft lip and palate (P < .001) and insignificant cross-sectional area compared with controls (P > .05). Patients with bilateral cleft lip and palate showed significantly larger depth than controls and those with unilateral cleft lip and palate (P < .001). Patients with unilateral cleft lip and palate showed insignificant nasopharyngeal airway volume, cross-sectional area, and depth compared with controls (P > .05).   Unilateral and bilateral cleft lip and palate patients did not show significantly less volume, cross-sectional area, or depth of nasopharyngeal airway than controls. From the results of this study we conclude that unilateral and bilateral cleft lip and palate patients at the studied age and stage of repaired clefts are not

  16. Accuracy and reliability of a novel method for fusion of digital dental casts and Cone Beam Computed Tomography scans.

    PubMed

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

    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 scanned, impressions were taken from the plaster models and the impressions were also scanned. Linear measurements were performed on all three models, to assess accuracy and reproducibility. Besides that, matching of the scanned plaster models and scanned impressions was done, to assess the accuracy of the matching procedure. Results show that all measurement errors are smaller than 0.2 mm, and that 81% is smaller than 0.1 mm. Matching of the scanned plaster casts and scanned impressions show a mean error between the two surfaces of the upper arch of 0.14 mm and for the lower arch of 0.18 mm. The time needed for reconstructing the CBCT scans to a digital patient, where the impressions are integrated into the CBCT scan of the patient takes about 15 minutes, with little variance between patients. In conclusion, we can state that this new method is a reliable method to integrate digital dental casts into CBCT scans. As far as radiation exposure, soft tissue deformation and digital handling processes are concerned, it is a significant improvement compared to the previously published methods.

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

    PubMed

    Meyer, Jürgen; Wilbert, Jürgen; Baier, Kurt; Guckenberger, Matthias; Richter, Anne; Sauer, Otto; Flentje, Michael

    2007-03-15

    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). 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. The system performance of the XVI system alone was very stable with mean translational and rotational errors of below 0.2 mm and below 0.2 degrees , 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 0.3 degrees for translational and rotational corrections, respectively. The gray value match was more accurate than the bone match. 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.

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

    PubMed Central

    Joo, Ji Hyeon; Kim, Yeon Joo; Kim, Young Seok; Cho, Young Pil; Lee, Ho Yeon; Jeong, Chang Young; Kwak, Jungwon; Cho, Byung Chul

    2016-01-01

    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. PMID:27307750

  19. Low-dose megavoltage cone-beam computed tomography for lung tumors using a high-efficiency image receptor

    SciTech Connect

    Sillanpaa, Jussi; Chang Jenghwa; Mageras, Gikas; Yorke, Ellen; Arruda, Fernando De; Rosenzweig, Kenneth E.; Munro, Peter; Seppi, Edward; Pavkovich, John; Amols, Howard

    2006-09-15

    We report on the capabilities of a low-dose megavoltage cone-beam computed tomography (MV CBCT) system. The high-efficiency image receptor consists of a photodiode array coupled to a scintillator composed of individual CsI crystals. The CBCT system uses the 6 MV beam from a linear accelerator. A synchronization circuit allows us to limit the exposure to one beam pulse [0.028 monitor units (MU)] per projection image. 150-500 images (4.2-13.9 MU total) are collected during a one-minute scan and reconstructed using a filtered backprojection algorithm. Anthropomorphic and contrast phantoms are imaged and the contrast-to-noise ratio of the reconstruction is studied as a function of the number of projections and the error in the projection angles. The detector dose response is linear (R{sup 2} value 0.9989). A 2% electron density difference is discernible using 460 projection images and a total exposure of 13 MU (corresponding to a maximum absorbed dose of about 12 cGy in a patient). We present first patient images acquired with this system. Tumors in lung are clearly visible and skeletal anatomy is observed in sufficient detail to allow reproducible registration with the planning kV CT images. The MV CBCT system is shown to be capable of obtaining good quality three-dimensional reconstructions at relatively low dose and to be clinically usable for improving the accuracy of radiotherapy patient positioning.

  20. SU-E-T-63: A Preliminary Study of Gold Nanoparticles Enhanced Cone Beam Computed Tomography

    SciTech Connect

    Chen, K; Sha, H; Yang, Y

    2015-06-15

    Purpose: Gold nanoparticles (GNPs) have potential of being used as a new-generation contrast agent to enhance CT imaging of cancer. This feasibility study is to determine the GNP concentration required to provide sufficient image contrast in small animal cone beam CT (CBCT) imaging. Methods: The GNPs used are nanorods with 10nm diameter and 44nm length. A 50µl GNP colloid with an original GNP concentration of 3.6mg/ml was diluted to five different concentrations at 2.4, 2.1, 2.0, 1.9 and 1.8mg/ml, respectively. The GNP colloid was enclosed in a 150µl vial, and the GNP colloid vial was submerged in a water bottle for CBCT. CBCTs were acquired with x-ray energy of 65kVp and tube current of 1.5mA. In addition, to evaluate the optimal x-ray energy for GNP detection in CBCT, the GNP colloid of 1.8mg/ml was also imaged at x-ray energy of 45kVp and 85kVp. Regions of interest were placed in axial CBCT slices contouring the GNP colloid volume and a same volume in the surrounding water to calculate the signal and contrast. Results: For the GNP colloid at concentrations of 3.6, 2.4, 2.1, 2.0, 1.9 and 1.8mg/ml, the image contrasts between GNP colloid and water were 68±4, 33±4, 23±3, 20±3, 13±4, and 10±3 HU, respectively. At 1.8mg/ml concentration level, the image contrasts were 16±3 and 7±4 HU, respectively, when the x-ray energy was set at 45kVp and 85kVp. Conclusion: The minimal GNP concentration required on our small animal CBCT was estimated to be around 1.8mg/ml due to the fact that the minimum image contrast for adequate differentiation in CT is about 8 HU. CBCT at lower x-ray energy, i.e. 45kVp, can provide better image contrast than at higher energies, i.e., 65kVp and 85kVp. A study of GNP enhanced CBCT for in vivo small animal imaging is ongoing efforts in our group.

  1. The use of cone beam computed tomography in the diagnosis and management of internal root resorption associated with chronic apical periodontitis: a case report.

    PubMed

    Perlea, Paula; Nistor, Cristina Coralia; Iliescu, Mihaela Georgiana; Iliescu, Alexandru Andrei

    2015-01-01

    Internal root resorption is a consequence of chronic pulp inflammation. Later on, the pulp necrosis followed by a chronic apical periodontitis is installed. Hence, usually, in clinical practice, both lesions have to be simultaneously managed. Conventional periapical radiograph is mandatory in diagnosis. Improving the diagnosis and management of both lesions, cone beam computed tomography proves to be more reliable than conventional radiography.

  2. Use of cone-beam computed tomography in the diagnosis of sensory nerve paresthesia secondary to orthodontic tooth movement: a clinical report.

    PubMed

    Chana, Randeep S; Wiltshire, William A; Cholakis, Anastasia; Levine, Gary

    2013-08-01

    In this article, we report an incident of transient neuropathy secondary to tooth movement involving the inferior alveolar nerve. This clinical report reflects the need to thoroughly examine potentially high-risk patients for neuropathy using advanced diagnostic tools such as cone-beam computed tomography when diagnosing and planning treatment.

  3. Management of complete impacted maxillary second deciduous molar with the aid of cone-beam computed tomography: Case report and a review of the literature

    PubMed Central

    Hashim, Hayder A; Al-Qahtani, Abdulmueen A; Taha, Samir M; Tharupeedikayil, Shailaja; Ahmed, Mutaz F

    2013-01-01

    Complete impaction of primary teeth is a very rare condition and less seen at the dental office compared with permanent dentition. To report the use of cone-beam computed tomography in the management of a 7-year-old boy with completely impacted maxillary second deciduous molar due to the presence of odontoma and a cystic lesion. PMID:24987655

  4. Examining Margin Reduction and Its Impact on Dose Distribution for Prostate Cancer Patients Undergoing Daily Cone-Beam Computed Tomography

    SciTech Connect

    Hammoud, Rabih Patel, Samir H.; Pradhan, Deepak; Kim, Jinkoo; Guan, Harrison; Li Shidong; Movsas, Benjamin

    2008-05-01

    Purpose: To examine the dosimetric impact of margin reduction and quantify residual error after three-dimensional (3D) image registration using daily cone-beam computed tomography (CBCT) for prostate cancer patients. Methods and Materials: One hundred forty CBCTs from 5 prostate cancer patients were examined. Two intensity-modulated radiotherapy plans were generated on CT simulation on the basis of two planning target volume (PTV) margins: 10 mm all around the prostate and seminal vesicles except 6 mm posteriorly (10/6) and 5 mm all around except 3 mm posteriorly (5/3). Daily CBCT using the Varian On-Board Imaging System was acquired. The 10/6 and 5/3 simulation plans were overlaid onto each CBCT, and each CBCT plan was calculated. To examine residual error, PlanCT/CBCT intensity-based 3D image registration was performed for prostate localization using center of mass and maximal border displacement. Results: Prostate coverage was within 2% between the 10/6 and 5/3 plans. Seminal vesicle coverage was reduced with the 5/3 plan compared with the 10/6 plan, with coverage difference within 7%. The 5/3 plan allowed 30-50% sparing of bladder and rectal high-dose regions. For residual error quantification, center of mass data show that 99%, 93%, and 96% of observations fall within 3 mm in the left-right, anterior-posterior, and superior-inferior directions, respectively. Maximal border displacement observations range from 79% to 99%, within 5 mm for all directions. Conclusion: Cone-beam CT dosimetrically validated a 10/6 margin when soft-tissue localization is not used. Intensity-based 3D image registration has the potential to improve target localization and to provide guidelines for margin definition.

  5. Novel information theory based method for superimposition of lateral head radiographs and cone beam computed tomography images

    PubMed Central

    Jacquet, W; Nyssen, E; Bottenberg, P; de Groen, P; Vande Vannet, B

    2010-01-01

    Objectives The aim was to introduce a novel alignment criterion, focus mutual information (FMI), for the superimposition of lateral cephalometric radiographs and three dimensional (3D) cone beam computed images as well as the assessment of the alignment characteristics of the new method and comparison of the novel methodology with the region of interest (ROI) approach. Methods Implementation of a FMI criterion-based methodology that only requires the approximate indication of stable structures in one single image. The robustness of the method was first addressed in a phantom experiment comparing the new technique with a ROI approach. Two consecutive cephalometric radiographs were then obtained, one before and one after functional twin block application. These images were then superimposed using alignment by FMI where the following were focused on, in several ways: (1) cranial base and acoustic meatus, (2) palatal plane and (3) mandibular symphysis. The superimposed images were subtracted and coloured. The applicability to cone beam CT (CBCT) is illustrated by the alignment of CBCT images acquired before and after craniofacial surgery. Results The phantom experiment clearly shows superior alignment when compared to the ROI approach (Wilcoxon n = 17, Z = −3.290, and P = 0.001), and robustness with respect to the choice of parameters (one-sample t-test n = 50, t = −12.355, and P = 0.000). The treatment effects are revealed clearly in the subtraction image of well-aligned cephalometric radiographs. The colouring scheme of the subtraction image emphasises the areas of change and visualizes the remodelling of the soft tissue. Conclusions FMI allows for cephalometry without tracing, it avoids the error inherent to the use of landmarks and the interaction of the practitioner is kept to a minimum. The robustness to focal distribution variations limits the influence of possible examiner inaccuracy. PMID:20395459

  6. A manufacturer's role in reducing the dose of cone beam computed tomography examinations: effect of beam filtration.

    PubMed

    Ludlow, J B

    2011-02-01

    The dosimetry of the Kodak 9500 cone beam CT (CBCT) unit (Carestream Health, Rochester, NY) was measured before and after installation of copper filtration. Dosimetry of a pre-production Kodak 9500 CBCT unit was compared with a current production unit with 0.4 mm of added filtration and increased kVp. Thermoluminescent dosimeter 100 chips were placed at 24 locations in a RANDO (radiation analogue dosimetry) head phantom (Nuclear Associates, Hicksville, NY). Small, medium and large adult default exposure settings were used in separate dosimeter runs for large and medium field of view (FOV) examinations with both units. Equivalent dose and effective dose were calculated using International Commission on Radiological Protection (ICRP) 1990 and 2007 tissue weights. Estimations of risk using 2007 ICRP calculations increased by an average of 77% for large FOV scans and 125% for the medium FOV scans in comparison with 1990 calculations. With added filtration, effective dose for medium FOV examinations for default settings were: small adult 76 µSv, medium adult 98 µSv, and large adult 166 µSv. Effective doses for large FOV examinations were: small adult 93 µSv, medium adult 163 µSv, and large adult 260 µSv. Effective dose was reduced by an average of 43% in examinations made with increased filtration and adjusted kVp. The manufacturer's installation of additional filtration with the adjustment of kVp in the Kodak 9500 CBCT unit resulted in significant patient dose reductions for examinations at all adult default settings.

  7. A manufacturer's role in reducing the dose of cone beam computed tomography examinations: effect of beam filtration

    PubMed Central

    Ludlow, J B

    2011-01-01

    Objectives The dosimetry of the Kodak 9500 cone beam CT (CBCT) unit (Carestream Health, Rochester, NY) was measured before and after installation of copper filtration. Methods Dosimetry of a pre-production Kodak 9500 CBCT unit was compared with a current production unit with 0.4 mm of added filtration and increased kVp. Thermoluminescent dosimeter 100 chips were placed at 24 locations in a RANDO (radiation analogue dosimetry) head phantom (Nuclear Associates, Hicksville, NY). Small, medium and large adult default exposure settings were used in separate dosimeter runs for large and medium field of view (FOV) examinations with both units. Equivalent dose and effective dose were calculated using International Commission on Radiological Protection (ICRP) 1990 and 2007 tissue weights. Results Estimations of risk using 2007 ICRP calculations increased by an average of 77% for large FOV scans and 125% for the medium FOV scans in comparison with 1990 calculations. With added filtration, effective dose for medium FOV examinations for default settings were: small adult 76 µSv, medium adult 98 µSv, and large adult 166 µSv. Effective doses for large FOV examinations were: small adult 93 µSv, medium adult 163 µSv, and large adult 260 µSv. Effective dose was reduced by an average of 43% in examinations made with increased filtration and adjusted kVp. Conclusion The manufacturer's installation of additional filtration with the adjustment of kVp in the Kodak 9500 CBCT unit resulted in significant patient dose reductions for examinations at all adult default settings. PMID:21239575

  8. Comparison of a Novel Weightbearing Cone Beam Computed Tomography Scanner Versus a Conventional Computed Tomography Scanner for Measuring Patellar Instability

    PubMed Central

    Marzo, John; Kluczynski, Melissa; Notino, Anthony; Bisson, Leslie

    2016-01-01

    Background: Conventional computed tomography (CT) images are routinely used for diagnosing patellofemoral instability and are obtained with the patient in a supine position, nonweightbearing, with the knee in full extension, and with leg muscles relaxed. A new portable extremity cone beam CT (CBCT) scanner has been developed that may allow for more accurate diagnosis, as imaging can be performed with the patient standing, the knee flexed, and with leg muscles active. Purpose/Hypothesis: The purpose of this study was to compare CT measurements of patellar alignment on a prototype scanner versus conventional scanner in patients with known patellar instability. The hypothesis was that the measurements obtained with the knee flexed and the patient weightbearing would be less than those obtained from the conventional CT scan. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty patients with a diagnosis of lateral patellar instability were imaged on both a conventional CT scanner and on a prototype CBCT scanner. Objective measures of patellofemoral alignment (tilt angle, congruence angle, tibial tuberosity–trochlear groove [TT-TG] offset) were assessed on images obtained from the prototype and conventional CT scans by 2 independent reviewers. Paired t tests were calculated to compare the mean measurement of patellofemoral alignment obtained from the prototype versus conventional CT. Interrater reliability was assessed using a 2-way mixed-effects model intraclass correlation coefficient (ICC) for tilt angle, congruence angle, and TT-TG offset on the prototype and conventional CT scans. Results: Measurements of patellofemoral alignment were significantly less when acquired by the new prototype CBCT scanner while subjects were weightbearing on a flexed knee. On the images from the prototype CBCT scan, the tilt angle averaged 18.2° ± 11.6° compared with 28.1° ± 7.1° on the conventional CT scan (P < .0001). The congruence angle was 3.0° ± 30

  9. [Clinical application of sinus floor elevation guided by cone-beam computer tomography].

    PubMed

    Zhou, Wen-qing; Chen, Jan-rong; Zhou, Yong-qiang; Wu, Yan-ping; Chen, Lu; Ding, Shui-qing

    2014-02-01

    To investigate the value of using con-beam computer tomography (CBCT) to evaluate bone volume in the edentulous area of posterior maxilla, and guide sinus floor elevation. Twenty eight patients who planed to receive dental implant in the posterior maxilla underwent CBCT scan. After analysis of residual bone height, 19 patients with 5-10 mm bone height below the sinus floor underwent transcrestal sinus floor elevation, while 7 patients with less than 5 mm bone height below the sinus floor underwent lateral window sinus floor elevation. The treatment outcomes were assessed postoperatively. CBCT detected bone deficiency in the posterior maxillary alveolar bone in 26 patients, mucus cyst of maxillary sinus in 1 patient and sinus septa in 2 patients. Nineteen patients underwent transcrestal sinus floor elevation, and 7 patients underwent lateral window sinus floor elevation. All patients completed final dental restorations, and the restorations achieved satisfactory function and esthetic. CBCT imaging plays an important role in determining bone quality in posterior maxilla and guiding sinus floor elevation. Supported by Social Undertakings Technological Innovation and Demonstration Program of Nantong City (HS2011035).

  10. Filtered-backprojection reconstruction for a cone-beam computed tomography scanner with independent source and detector rotations

    SciTech Connect

    Rit, Simon; Clackdoyle, Rolf; Keuschnigg, Peter; Steininger, Philipp

    2016-05-15

    Purpose: A new cone-beam CT scanner for image-guided radiotherapy (IGRT) can independently rotate the source and the detector along circular trajectories. Existing reconstruction algorithms are not suitable for this scanning geometry. The authors propose and evaluate a three-dimensional (3D) filtered-backprojection reconstruction for this situation. Methods: The source and the detector trajectories are tuned to image a field-of-view (FOV) that is offset with respect to the center-of-rotation. The new reconstruction formula is derived from the Feldkamp algorithm and results in a similar three-step algorithm: projection weighting, ramp filtering, and weighted backprojection. Simulations of a Shepp Logan digital phantom were used to evaluate the new algorithm with a 10 cm-offset FOV. A real cone-beam CT image with an 8.5 cm-offset FOV was also obtained from projections of an anthropomorphic head phantom. Results: The quality of the cone-beam CT images reconstructed using the new algorithm was similar to those using the Feldkamp algorithm which is used in conventional cone-beam CT. The real image of the head phantom exhibited comparable image quality to that of existing systems. Conclusions: The authors have proposed a 3D filtered-backprojection reconstruction for scanners with independent source and detector rotations that is practical and effective. This algorithm forms the basis for exploiting the scanner’s unique capabilities in IGRT protocols.

  11. Utility of cone-beam computed tomography in the assessment of the porto-spleno-mesenteric venous system

    PubMed Central

    2016-01-01

    The common diagnostic tools available to evaluate the porto-spleno-mesenteric venous (PSMV) system provide either good hemodynamic information with limited morphological details [e.g., ultrasonography (US)] or excellent tomographic display of the anatomy with limited information about flow patterns [e.g., multidetector computed tomography (MDCT) and magnetic resonance imaging]. Although catheter-directed selective digital subtraction angiography (DSA) can provide excellent information about flow at a high temporal resolution and can generate images at a high spatial resolution, this technique is often limited by a lack of cross-sectional detail. In the assessment of the PSMV system, DSA is also limited by dilution of contrast and motion artefacts. Combining venous phase cone-beam computed tomography (CBCT) with DSA can generate high-quality tomographic data, which allows detailed evaluation of venous tributaries and flow patterns within the splenic, superior mesenteric, and inferior mesenteric venous systems individually. This enables clinicians to better understand the impact of nonobstructive resistance to flow (e.g., as in patients with cirrhosis) and obstructive resistance to flow (e.g., as in patients with thrombosis) within each system and plan treatment accordingly. In this review, we discuss the limitations of common diagnostic methods and the role venous CBCT in combination with DSA can play in assessing the PSMV system. PMID:28123975

  12. Evaluation of the effect of patient dose from cone beam computed tomography on prostate IMRT using Monte Carlo simulation

    SciTech Connect

    Chow, James C. L.; Leung, Michael K. K.; Islam, Mohammad K.; Norrlinger, Bernhard D.; Jaffray, David A.

    2008-01-15

    The aim of this study is to evaluate the impact of the patient dose due to the kilovoltage cone beam computed tomography (kV-CBCT) in a prostate intensity-modulated radiation therapy (IMRT). The dose distributions for the five prostate IMRTs were calculated using the Pinnacle3 treatment planning system. To calculate the patient dose from CBCT, phase-space beams of a CBCT head based on the ELEKTA x-ray volume imaging system were generated using the Monte Carlo BEAMnrc code for 100, 120, 130, and 140 kVp energies. An in-house graphical user interface called DOSCTP (DOSXYZnrc-based) developed using MATLAB was used to calculate the dose distributions due to a 360 deg. photon arc from the CBCT beam with the same patient CT image sets as used in Pinnacle3. The two calculated dose distributions were added together by setting the CBCT doses equal to 1%, 1.5%, 2%, and 2.5% of the prescription dose of the prostate IMRT. The prostate plan and the summed dose distributions were then processed in the CERR platform to determine the dose-volume histograms (DVHs) of the regions of interest. Moreover, dose profiles along the x- and y-axes crossing the isocenter with and without addition of the CBCT dose were determined. It was found that the added doses due to CBCT are most significant at the femur heads. Higher doses were found at the bones for a relatively low energy CBCT beam such as 100 kVp. Apart from the bones, the CBCT dose was observed to be most concentrated on the anterior and posterior side of the patient anatomy. Analysis of the DVHs for the prostate and other critical tissues showed that they vary only slightly with the added CBCT dose at different beam energies. On the other hand, the changes of the DVHs for the femur heads due to the CBCT dose and beam energy were more significant than those of rectal and bladder wall. By analyzing the vertical and horizontal dose profiles crossing the femur heads and isocenter, with and without the CBCT dose equal to 2% of the

  13. Breast Patient Setup Error Assessment: Comparison of Electronic Portal Image Devices and Cone-Beam Computed Tomography Matching Results

    SciTech Connect

    Topolnjak, Rajko; Sonke, Jan-Jakob; Nijkamp, Jasper; Rasch, Coen; Minkema, Danny; Remeijer, Peter; Vliet-Vroegindeweij, Corine van

    2010-11-15

    Purpose: To quantify the differences in setup errors measured with the cone-beam computed tomography (CBCT) and electronic portal image devices (EPID) in breast cancer patients. Methods and Materials: Repeat CBCT scan were acquired for routine offline setup verification in 20 breast cancer patients. During the CBCT imaging fractions, EPID images of the treatment beams were recorded. Registrations of the bony anatomy for CBCT to planning CT and EPID to digitally reconstructed-radiographs (DRRs) were compared. In addition, similar measurements of an anthropomorphic thorax phantom were acquired. Bland-Altman and linear regression analysis were performed for clinical and phantom registrations. Systematic and random setup errors were quantified for CBCT and EPID-driven correction protocols in the EPID coordinate system (U, V), with V parallel to the cranial-caudal axis and U perpendicular to V and the central beam axis. Results: Bland-Altman analysis of clinical EPID and CBCT registrations yielded 4 to 6-mm limits of agreement, indicating that both methods were not compatible. The EPID-based setup errors were smaller than the CBCT-based setup errors. Phantom measurements showed that CBCT accurately measures setup error whereas EPID underestimates setup errors in the cranial-caudal direction. In the clinical measurements, the residual bony anatomy setup errors after offline CBCT-based corrections were {Sigma}{sub U} = 1.4 mm, {Sigma}{sub V} = 1.7 mm, and {sigma}{sub U} = 2.6 mm, {sigma}{sub V} = 3.1 mm. Residual setup errors of EPID driven corrections corrected for underestimation were estimated at {Sigma}{sub U} = 2.2mm, {Sigma}{sub V} = 3.3 mm, and {sigma}{sub U} = 2.9 mm, {sigma}{sub V} = 2.9 mm. Conclusion: EPID registration underestimated the actual bony anatomy setup error in breast cancer patients by 20% to 50%. Using CBCT decreased setup uncertainties significantly.

  14. Accuracy of Image Guidance Using Free-Breathing Cone-Beam Computed Tomography for Stereotactic Lung Radiotherapy

    PubMed Central

    Kamomae, Takeshi; Monzen, Hajime; Nakayama, Shinichi; Mizote, Rika; Oonishi, Yuuichi; Kaneshige, Soichiro; Sakamoto, Takashi

    2015-01-01

    Movement of the target object during cone-beam computed tomography (CBCT) leads to motion blurring artifacts. The accuracy of manual image matching in image-guided radiotherapy depends on the image quality. We aimed to assess the accuracy of target position localization using free-breathing CBCT during stereotactic lung radiotherapy. The Vero4DRT linear accelerator device was used for the examinations. Reference point discrepancies between the MV X-ray beam and the CBCT system were calculated using a phantom device with a centrally mounted steel ball. The precision of manual image matching between the CBCT and the averaged intensity (AI) images restructured from four-dimensional CT (4DCT) was estimated with a respiratory motion phantom, as determined in evaluations by five independent operators. Reference point discrepancies between the MV X-ray beam and the CBCT image-guidance systems, categorized as left-right (LR), anterior-posterior (AP), and superior-inferior (SI), were 0.33 ± 0.09, 0.16 ± 0.07, and 0.05 ± 0.04 mm, respectively. The LR, AP, and SI values for residual errors from manual image matching were -0.03 ± 0.22, 0.07 ± 0.25, and -0.79 ± 0.68 mm, respectively. The accuracy of target position localization using the Vero4DRT system in our center was 1.07 ± 1.23 mm (2 SD). This study experimentally demonstrated the sufficient level of geometric accuracy using the free-breathing CBCT and the image-guidance system mounted on the Vero4DRT. However, the inter-observer variation and systematic localization error of image matching substantially affected the overall geometric accuracy. Therefore, when using the free-breathing CBCT images, careful consideration of image matching is especially important. PMID:25954809

  15. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    NASA Astrophysics Data System (ADS)

    Reitz, Bodo; Gayou, Olivier; Parda, David S.; Miften, Moyed

    2008-02-01

    Accurate daily patient localization is becoming increasingly important in external-beam radiotherapy (RT). Mega-voltage cone-beam computed tomography (MV-CBCT) utilizing a therapy beam and an on-board electronic portal imager can be used to localize tumor volumes and verify the patient's position prior to treatment. MV-CBCT produces a static volumetric image and therefore can only account for inter-fractional changes. In this work, the feasibility of using the MV-CBCT raw data as a fluoroscopic series of portal images to monitor tumor changes due to e.g. respiratory motion was investigated. A method was developed to read and convert the CB raw data into a cine. To improve the contrast-to-noise ratio on the MV-CB projection data, image post-processing with filtering techniques was investigated. Volumes of interest from the planning CT were projected onto the MV-cine. Because of the small exposure and the varying thickness of the patient depending on the projection angle, soft-tissue contrast was limited. Tumor visibility as a function of tumor size and projection angle was studied. The method was well suited in the upper chest, where motion of the tumor as well as of the diaphragm could be clearly seen. In the cases of patients with non-small cell lung cancer with medium or large tumor masses, we verified that the tumor mass was always located within the PTV despite respiratory motion. However for small tumors the method is less applicable, because the visibility of those targets becomes marginal. Evaluation of motion in non-superior-inferior directions might also be limited for small tumor masses. Viewing MV-CBCT data in a cine mode adds to the utility of MV-CBCT for verification of tumor motion and for deriving individualized treatment margins.

  16. Assessment of Facial Soft Tissue Dimensions in Adult Patients with Different Sagittal Skeletal Classes using Cone beam Computed Tomography.

    PubMed

    Jazmati, Heba M; Ajaj, Mowaffak A; Hajeer, Mohammad Y

    2016-07-01

    Few studies utilized cone beam computed tomography (CBCT) to evaluate soft tissue dimensions in malocclusion patients. The aim of this study was to analyze the three-dimensional (3D) soft tissue relationships of adult patients according to their gender and skeletal sagittal class using CBCT Materials and methods: The study sample consisted of 96 CBCT images of patients of both genders; aged 18 to 25 years with a normal vertical skeletal pattern. Patients were segregated into three groups according to their skeletal sagittal class: Class I (2 < ANB < 4), class II (ANB > 4), and class III (ANB < 2). The soft tissue measurements were analyzed in both the sagittal views and frontal volumetric rendered views using 3D-OnDemand software. In males, the measurements (U1-stom, nasal width, mouth width) were greater in class I than in class II group. Lower lip thickness was greater in class I than in class III group (p < 0.05). In females, both labiomental fold thickness and upper lip height measurements showed greater mean values in class II than in class I group. In contrast, lower lip height was greater in class I than in class III group. Ls-Pr, U1-stom, and face width at Cheilion revealed greater values in class III patients than in class II patients. On the other hand, the lower lip thickness, upper lip height, and lower lip height measurements showed greater values in class II than in class III group (p < 0.05). Soft tissue thicknesses and measurements were greater in males than in females. However, statistically significant differences between the two sexes were not detected for all of the variables measured in each skeletal class. The current study indicates the presence of differences in soft tissue thicknesses and facial soft tissue dimensions among skeletal classes and between the two sexes. Cone beam computed tomography imaging is a very valuable tool to analyze 3D soft tissue characteristics of patients with different skeletal patterns of malocclusion.

  17. Value of C-Arm Cone Beam Computed Tomography Image Fusion in Maximizing the Versatility of Endovascular Robotics.

    PubMed

    Chinnadurai, Ponraj; Duran, Cassidy; Al-Jabbari, Odeaa; Abu Saleh, Walid K; Lumsden, Alan; Bismuth, Jean

    2016-01-01

    To report our initial experience and highlight the value of using intraoperative C-arm cone beam computed tomography (CT; DynaCT(®)) image fusion guidance along with steerable robotic endovascular catheter navigation to optimize vessel cannulation. Between May 2013 and January 2015, all patients who underwent endovascular procedures using DynaCT image fusion technique along with Hansen Magellan vascular robotic catheter were included in this study. As a part of preoperative planning, relevant vessel landmarks were electronically marked in contrast-enhanced multi-slice computed tomography images and stored. At the beginning of procedure, an intraoperative noncontrast C-arm cone beam CT (syngo DynaCT(®), Siemens Medical Solutions USA Inc.) was acquired in the hybrid suite. Preoperative images were then coregistered to intraoperative DynaCT images using aortic wall calcifications and bone landmarks. Stored landmarks were then overlaid on 2-dimensional (2D) live fluoroscopic images as virtual markers that are updated in real-time with C-arm, table movements and image zoom. Vascular access and robotic catheter (Magellan(®), Hansen Medical) was setup per standard. Vessel cannulation was performed based on electronic virtual markers on live fluoroscopy using robotic catheter. The impact of 3-dimensional (3D) image fusion guidance on robotic vessel cannulation was evaluated retrospectively, by assessing quantitative parameters like number of angiograms acquired before vessel cannulation and qualitative parameters like accuracy of vessel ostium and centerline markers. All 17 vessels were cannulated successfully in 14 patients' attempted using robotic catheter and image fusion guidance. Median vessel diameter at origin was 5.4 mm (range, 2.3-13 mm), whereas 12 of 17 (70.6%) vessels had either calcified and/or stenosed origin from parent vessel. Nine of 17 vessels (52.9 %) were cannulated without any contrast injection. Median number of angiograms required before

  18. Ultrafast and scalable cone-beam CT reconstruction using MapReduce in a cloud computing environment

    PubMed Central

    Meng, Bowen; Pratx, Guillem; Xing, Lei

    2011-01-01

    Purpose: Four-dimensional CT (4DCT) and cone beam CT (CBCT) are widely used in radiation therapy for accurate tumor target definition and localization. However, high-resolution and dynamic image reconstruction is computationally demanding because of the large amount of data processed. Efficient use of these imaging techniques in the clinic requires high-performance computing. The purpose of this work is to develop a novel ultrafast, scalable and reliable image reconstruction technique for 4D CBCT/CT using a parallel computing framework called MapReduce. We show the utility of MapReduce for solving large-scale medical physics problems in a cloud computing environment. Methods: In this work, we accelerated the Feldcamp–Davis–Kress (FDK) algorithm by porting it to Hadoop, an open-source MapReduce implementation. Gated phases from a 4DCT scans were reconstructed independently. Following the MapReduce formalism, Map functions were used to filter and backproject subsets of projections, and Reduce function to aggregate those partial backprojection into the whole volume. MapReduce automatically parallelized the reconstruction process on a large cluster of computer nodes. As a validation, reconstruction of a digital phantom and an acquired CatPhan 600 phantom was performed on a commercial cloud computing environment using the proposed 4D CBCT/CT reconstruction algorithm. Results: Speedup of reconstruction time is found to be roughly linear with the number of nodes employed. For instance, greater than 10 times speedup was achieved using 200 nodes for all cases, compared to the same code executed on a single machine. Without modifying the code, faster reconstruction is readily achievable by allocating more nodes in the cloud computing environment. Root mean square error between the images obtained using MapReduce and a single-threaded reference implementation was on the order of 10−7. Our study also proved that cloud computing with MapReduce is fault tolerant: the

  19. Ultrafast and scalable cone-beam CT reconstruction using MapReduce in a cloud computing environment.

    PubMed

    Meng, Bowen; Pratx, Guillem; Xing, Lei

    2011-12-01

    Four-dimensional CT (4DCT) and cone beam CT (CBCT) are widely used in radiation therapy for accurate tumor target definition and localization. However, high-resolution and dynamic image reconstruction is computationally demanding because of the large amount of data processed. Efficient use of these imaging techniques in the clinic requires high-performance computing. The purpose of this work is to develop a novel ultrafast, scalable and reliable image reconstruction technique for 4D CBCT∕CT using a parallel computing framework called MapReduce. We show the utility of MapReduce for solving large-scale medical physics problems in a cloud computing environment. In this work, we accelerated the Feldcamp-Davis-Kress (FDK) algorithm by porting it to Hadoop, an open-source MapReduce implementation. Gated phases from a 4DCT scans were reconstructed independently. Following the MapReduce formalism, Map functions were used to filter and backproject subsets of projections, and Reduce function to aggregate those partial backprojection into the whole volume. MapReduce automatically parallelized the reconstruction process on a large cluster of computer nodes. As a validation, reconstruction of a digital phantom and an acquired CatPhan 600 phantom was performed on a commercial cloud computing environment using the proposed 4D CBCT∕CT reconstruction algorithm. Speedup of reconstruction time is found to be roughly linear with the number of nodes employed. For instance, greater than 10 times speedup was achieved using 200 nodes for all cases, compared to the same code executed on a single machine. Without modifying the code, faster reconstruction is readily achievable by allocating more nodes in the cloud computing environment. Root mean square error between the images obtained using MapReduce and a single-threaded reference implementation was on the order of 10(-7). Our study also proved that cloud computing with MapReduce is fault tolerant: the reconstruction completed

  20. Accuracy of a plastic facial cast fabricated with a custom tray in comparison with cone beam computed tomography.

    PubMed

    Xu, Yi; Li, Jingtao; Zhao, Shufan; Shi, Bing; Zheng, Qian; Wang, Yan

    2014-03-01

    The aim of this study was to test the accuracy of a plaster cast fabricated with a facial custom tray. Sixteen patients with unilateral cleft lip and palate were enrolled in this study. Cone beam computed tomography (CBCT) scanning and facial plaster cast were obtained before surgery. Three-dimensional (3D) coordinates of 6 selected landmarks were recorded directly in CBCT by Mimics and indirectly on the plaster cast by using an electronic caliper and parallel milling machine. The accuracy of the plaster cast was compared with that of CBCT by using the t test and Lin's concordance correlation coefficient. P values less than 0.05 were considered statistically significant. Horizontal and vertical measurements were larger and sagittal measurements were smaller in plaster cast measurements, but none of these differences was statistically significant (P values ranged from 0.063 to 0.774). Lin's agreement test also showed that the plaster cast had high agreement with CBCT measurements (concordance correlation coefficients ranged from 0.6319 to 0.9599). Plaster cast fabricated with a custom tray is an accurate method in facial 3D analysis. Crown Copyright © 2014. Published by Mosby, Inc. All rights reserved.

  1. Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

    PubMed Central

    Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

    2016-01-01

    Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

  2. Analysis of the greater palatine foramen in a Lebanese population using cone-beam computed tomography technology

    PubMed Central

    Aoun, Georges; Nasseh, Ibrahim; Sokhn, Sayde; Saadeh, Maria

    2015-01-01

    Objective: The aim of this study was to describe the diameter and the position of the greater palatine foramen (GPF) in relation to adjacent anatomical landmarks in the maxilla in a Lebanese population using cone-beam computed tomography (CBCT) technology. Materials and Methods: CBCT images of 58 Lebanese adult patients were included in this study and a total of 116 GPF were evaluated bilaterally. The diameter of the GPF and its position relative to the maxillary molars, and distances to the midline maxillary suture and to the anterior nasal spine were analyzed. Results: Of all foramina assessed, 41.38% were located opposite to the third molar, 29.31% were distal to it, 27.59% were between the second and the third, and only 1.72% were opposite to the second. The average diameter was 5.633 mm on the right and 5.723 mm on the left, and the average distances to midline maxillary suture and anterior nasal spine were 16.228 mm and 48.294 mm on the right and 14.907 mm and 48.122 mm on the left, respectively. Conclusion: Within the limits of this study, we conclude that in Lebanese patients, the GPF location is variable, very rarely opposite to the second molar, and more closely related to the third, but may present mesial or distal to it in one-fourth of patients. PMID:26942122

  3. Canal Transportation and Centering Ability of Twisted File and Reciproc: A Cone-Beam Computed Tomography Assessment

    PubMed Central

    Nazari Moghadam, Kiumars; Shahab, Shahriar; Rostami, Golriz

    2014-01-01

    Introduction: The purpose of this in vitro study was to compare the canal transportation and centering ability of Twisted File (TF) to that of Reciproc system. Methods and Materials: Forty noncalcified roots with mature apices, minimum length of 19 mm and an apical curvature of 15-30 degrees (according to Schneider’s method), from freshly extracted mandibular and maxillary teeth, were selected for this study. Samples were randomly divided into two groups (n=20) and canal preparation with either TF or Reciproc was performed according to manufacturers' instruction. Pre- and post-instrumentation cone-beam computed tomography (CBCT) images were captured and the extent of canal transportation and centering ability of the files were calculated, using the NNT Viewer software and Photoshop CS5, at levels of 3, 4, and 5 mm from the apex. The Mann-Whitney U test was used to analyze the statistical significance between the two groups. Results: One fracture occurred in the TF group. TF produced more transportation than Reciproc in both mesiodistal and buccolingual directions; however, the difference between the two systems were not statistically significant except for the TF group at 5-mm distance from the working length, where the difference was significant (P>0.05). Conclusion: Both file systems were able keep the original curvature of the canal and thus can be considered safe for clinical application. PMID:25031589

  4. Comparison between dental and basal arch forms in normal occlusion and Class III malocclusions utilizing cone-beam computed tomography

    PubMed Central

    Suk, Kyung Eun; Park, Jae Hyun; Bayome, Mohamed; Nam, Young-Ok; Sameshima, Glenn T.

    2013-01-01

    Objective The purpose of this study was to investigate the relationship between the mandibular dental and basal arch forms in subjects with normal occlusion and compare them with those of Class III malocclusion using cone-beam computed tomography (CBCT). Methods CBCT images of 32 normal occlusion (19 males, 13 females; 24.3 years) and 33 Class III malocclusion subjects (20 males, 13 females, 22.2 years) were selected. Facial axis and root center points were identified from the left to right mandibular first molars. Distances between the facial axis and root center points for each tooth were calculated, and 4 linear and 2 ratio variables were measured and calculated for each arch form. The variables were compared between groups by independent t-test. Pearson correlation coefficient was applied to assess the relationships between dental and basal variables within each group. Results The mandibular dental and basal intercanine widths were significantly greater in the Class III group than in normal occlusion subjects (p < 0.05). The dental and basal intercanine widths as well as the dental and basal intermolar widths were strongly correlated in normal occlusion and moderately correlated in Class III malocclusion. Conclusions The dental arch form demon strated a strong positive correlation with the basal arch form in the normal occlusion group and moderate correlation in the Class III malocclusion group. These results might be helpful for clinicians to have a better understanding of the importance of basal arch form in the alveolar bone. PMID:23504406

  5. A feasibility study of applying cone-beam computed tomography to observe dimensional changes in human alveolar bone*

    PubMed Central

    Li, Bei; Wang, Yao; Li, Jun

    2014-01-01

    The purpose of this study was to demonstrate the feasibility of applying cone-beam computed tomography (CBCT) to observe dimensional changes in human alveolar bone continuously after tooth extraction. Sixty patients were selected from a CBCT database. Each patient had two CBCT scans (CBCT I and CBCT II), one taken before and one taken after implant surgery. A fixed anatomic reference point was used to orient the horizontal slice of the two scans. The alveolar ridge width was measured on the horizontal slice. In each series of CBCT I sagittal slices, the number of slices from the start point to the pulp center of the test tooth was recorded. The tooth length was measured on the sagittal slice. In each series of CBCT II slices, tooth length was measured on a sagittal slice selected based on the number of slices from the start point to the pulp center recorded in CBCT I. Intraobserver reliability, assessed by the intraclass correlation coefficient (ICC), was high. Paired sample t-tests of repeated measurements of both tooth length and alveolar bone width showed no statistically significant differences (P<0.05). This study has proved that projection differences among CBCT scans taken at different time points from one patient can be neglected without affecting the accuracy of millimeter scale measurements. CBCT is a reliable imaging tool for continuously observing dimensional changes in human alveolar bone. PMID:24711360

  6. Sensitivity and specificity of cone beam computed tomography in thin bony structures in maxillofacial surgery – A clinical trial.

    PubMed

    Thönissen, P; Ermer, M A; Schmelzeisen, R; Gutwald, R; Metzger, M C; Bittermann, G

    2015-09-01

    Cone-Beam Computed Tomography (CBCT) has become widely used in dentistry and maxillofacial surgery. Accuracy, sensitivity and specificity of thin bony structures below 0.5 mm have been subject of some in vitro studies. This prospective in vivo study investigates the correlation between preoperative CBCT-imaging and intraoperative clinical examination of thin bony structures. We hereby present results from daily clinical routine. A total number of 80 sites in 64 patients has been examined to differentiate between preoperative 3D imaging and clinical measurements on cystic lesions in maxilla and mandible. Different CBCT-devices with a voxel size ranging from 0.08 mm to 0.4 mm were used. Overall-specificity found for detecting thin bony structures of the human jaw is 13.89%, overall sensitivity is 100%, positive predictive value (PPV) is 58.67% and negative predictive value (NPV) is 100%. Image quality is the key to make use of additional information CBCT provides and depends on spatial, temporal and contrast resolution. CBCT does not depict reliably thin bony structures of the jaw, even if high voxel resolution is used. In selected cases using high resolution protocols should be considered despite affecting the patient with higher doses of radiation. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model

    PubMed Central

    Gowd, Snigdha; Shankar, T; Dash, Samarendra; Sahoo, Nivedita; Chatterjee, Suravi; Mohanty, Pritam

    2017-01-01

    Aims and Objective: The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. Materials and Methods: Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t-test was performed to qualitatively evaluate the data and P < 0.05 was considered statistically significant. Results: Statistically, significant results were obtained on data comparison between CBCT-derived images and plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. Conclusion: CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis. PMID:28852639

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

    PubMed Central

    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

  9. Investigation of the effects of storage time on the dimensional accuracy of impression materials using cone beam computed tomography.

    PubMed

    Alkurt, Murat; Yeşıl Duymus, Zeynep; Dedeoglu, Numan

    2016-10-01

    The storage conditions of impressions affect the dimensional accuracy of the impression materials. The aim of the study was to assess the effects of storage time on dimensional accuracy of five different impression materials by cone beam computed tomography (CBCT). Polyether (Impregum), hydrocolloid (Hydrogum and Alginoplast), and silicone (Zetaflow and Honigum) impression materials were used for impressions taken from an acrylic master model. The impressions were poured and subjected to four different storage times: immediate use, and 1, 3, and 5 days of storage. Line 1 (between right and left first molar mesiobuccal cusp tips) and Line 2 (between right and left canine tips) were measured on a CBCT scanned model, and time dependent mean differences were analyzed by two-way univariate and Duncan's test (α=.05). For Line 1, the total mean difference of Impregum and Hydrogum were statistically different from Alginoplast (P<.05), while Zetaflow and Honigum had smaller discrepancies. Alginoplast resulted in more difference than the other impressions (P<.05). For Line 2, the total mean difference of Impregum was statistically different from the other impressions. Significant differences were observed in Line 1 and Line 2 for the different storage periods (P<.05). The dimensional accuracy of impression material is clinically acceptable if the impression material is stored in suitable conditions.

  10. Comparison of Cone Beam Computed Tomography-Derived Alveolar Bone Density Between Subjects with and without Aggressive Periodontitis

    PubMed Central

    Al-Zahrani, Mohammad S.; Elfirt, Eman Y.; Al-Ahmari, Manea M.; Yamany, Ibrahim A.; Alabdulkarim, Maher A.

    2017-01-01

    Introduction Understanding the changes in bone density of patients affected by aggressive periodontitis could be useful in early disease detection and proper treatment planning. Aim The aim of this study was to compare alveolar bone density in patients affected with aggressive periodontitis and periodontally healthy individuals using Cone Beam Computed Tomography (CBCT). Materials and Methods This cross-sectional study was conducted on 20 patients with a confirmed diagnosis of aggressive periodontitis. Twenty periodontally healthy patients attending the dental clinics for implant placement or extraction of impacted third molars served as controls. Alveolar bone density was measured using CBCT scanning. Comparisons between aggressive periodontitis group and controls for age and alveolar bone density of the anterior and posterior regions were performed using an independent sample t-test. Multivariable linear regression models were also performed. Results The differences between groups in regard to age, anterior and posterior alveolar bone density was not statistically significant (p<0.05). In the posterior region, the multivariable regression model showed that bone density was not associated with age, gender or the study groups. Whereas, in the anterior region, patient’s age was found to be significantly associated with bone density, p=0.014. Conclusion Alveolar bone density as measured by CBCT in aggressive periodontitis patients was not different from periodontally healthy individuals. Further studies are needed to confirm these findings. PMID:28274060

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

    PubMed Central

    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

  12. Assessment of slice thickness effect on visibility of inferior alveolar canal in cone beam computed tomography images

    PubMed Central

    Pour, Daryoush Goodarzi; Arzi, Banafsheh; Shamshiri, Ahmad Reza

    2016-01-01

    Objective: The aim of this study is to evaluate the effect of slice thickness on the visibility of inferior alveolar canal (IAC) in cone-beam computed tomography (CBCT) images. Materials and Methods: CBCT images of thirty patients (15 male and 15 female) with an age range between 40–50 years old were used. Cross-sectional images were obtained with 0.5, 1, and 2 mm slice thickness and 2 mm interval. Two oral radiologists with at least 5 years' of experience observed all of the 90 images and rated the images based on the visibility of IAC in a 4-score classification (highly visible, visible, nearly visible, nearly invisible). Friedman test was used for the comparison of visibility of IAC in different slice thicknesses. To do the above test, the average of the scores of two examiners was calculated. A P. value below 0.05 was considered significant. Results: Visibility of IAC in different slice thicknesses of both raters showed no significant difference (P = 0.20). Conclusion: Within the limitations of this study the slice thickness has no effect on visibility of IAC in cross-sectional images. Future studies on other multiplanar images are recommended. PMID:28182059

  13. Monte-Carlo scatter correction for cone-beam computed tomography with limited scan field-of-view

    NASA Astrophysics Data System (ADS)

    Bertram, Matthias; Sattel, Timo; Hohmann, Steffen; Wiegert, Jens

    2008-03-01

    In flat detector cone-beam computed tomography (CBCT), scattered radiation is a major source of image degradation, making accurate a posteriori scatter correction inevitable. A potential solution to this problem is provided by computerized scatter correction based on Monte-Carlo simulations. Using this technique, the detected distributions of X-ray scatter are estimated for various viewing directions using Monte-Carlo simulations of an intermediate reconstruction. However, as a major drawback, for standard CBCT geometries and with standard size flat detectors such as mounted on interventional C-arms, the scan field of view is too small to accommodate the human body without lateral truncations, and thus this technique cannot be readily applied. In this work, we present a novel method for constructing a model of the object in a laterally and possibly also axially extended field of view, which enables meaningful application of Monte-Carlo based scatter correction even in case of heavy truncations. Evaluation is based on simulations of a clinical CT data set of a human abdomen, which strongly exceeds the field of view of the simulated C-arm based CBCT imaging geometry. By using the proposed methodology, almost complete removal of scatter-caused inhomogeneities is demonstrated in reconstructed images.

  14. Cone-Beam Computed Tomographic Assessment of Mandibular Condylar Position in Patients with Temporomandibular Joint Dysfunction and in Healthy Subjects.

    PubMed

    Paknahad, Maryam; Shahidi, Shoaleh; Iranpour, Shiva; Mirhadi, Sabah; Paknahad, Majid

    2015-01-01

    Statement of the Problem. The clinical significance of condyle-fossa relationships in the temporomandibular joint is a matter of controversy. Different studies have evaluated whether the position of the condyle is a predictor of the presence of temporomandibular disorder. Purpose. The purpose of the present study was to investigate the condylar position according to gender in patients with temporomandibular disorder (TMD) and healthy controls using cone-beam computed tomography. Materials and Methods. CBCT of sixty temporomandibular joints in thirty patients with TMD and sixty joints of thirty subjects without TMJ disorder was evaluated in this study. The condylar position was assessed on the CBCT images. The data were analyzed using Pearson chi-square test. Results. No statistically significant differences were found regarding the condylar position between symptomatic and asymptomatic groups. Posterior condylar position was more frequently observed in women and anterior condylar position was more prevalent in men in the symptomatic group. However, no significant differences in condylar position were found in asymptomatic subjects according to gender. Conclusion. This study showed no apparent association between condylar positioning and clinical findings in TMD patients.

  15. Map-reading strategy to diagnose root perforations near metallic intracanal posts by using cone beam computed tomography.

    PubMed

    Bueno, Mike Reis; Estrela, Carlos; De Figueiredo, José Antônio Poli; Azevedo, Bruno Correa

    2011-01-01

    To determine the diagnostic hypothesis on the basis of periapical radiography (PR) is a great challenge for radiologists and endodontists. Visualization of three-dimensional structures, available with cone beam computed tomography (CBCT), favors precise definition of the problem and treatment planning. However, metallic artifact effect of intracanal posts might also induce untrue images. The aim of this article is to suggest a map-reading strategy to diagnose root perforations near metallic intracanal posts (ICPs) by using CBCT. The incapacity to locate correctly the position of root perforation might lead to clinical failures. One strategy to minimize metallic artifact in root perforation associated with ICP is to obtain sequential axial slices of each root, with an image navigation protocol from coronal to apical (or from apical to coronal), with axial slices of 0.2 mm/0.2 mm. This map reading provides valuable information showing dynamic visualization toward the point of communication between the root canals and the periodontal space, associated with radiolucent areas, suggesting root perforation. The accurate management of CBCT images might reveal abnormality that is unable to be detected in conventional PR. A map-reading approach reduces problems related to detection of root perforations near metallic artifacts. The final diagnosis should always be made in conjunction with the clinical findings. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Open Sinus Lift Surgery and the Importance of Preoperative Cone-Beam Computed Tomography Scan: A Review

    PubMed Central

    Rahpeyma, Amin; Khajehahmadi, Saeedeh

    2015-01-01

    Open sinus lift surgery is a form of pre-prosthetic surgery for increasing the quality and quantity of bone in the posterior region of the maxilla. Pre-operative assessment of the maxillary sinus is essential for the success of this surgery. PubMed search was carried out in English language literature for open sinus lift surgery and cone-beam computed tomography (CBCT). The results focused on anatomic variants, vascular anatomy, complications, osteotomy/ostectomy window dimensions and thickness of the Schneiderian Membrane. 59 articles were included in this review. Features other than the height and the width of the residual alveolar ridge that should be evaluated in preoperative CBCT scan include the thickness of the lateral maxillary sinus wall, the presence of the alveolar antral artery and its diameter, the maxillary sinus floor width and angulation, irregularity of sinus floor, intimate relation of Schneiderian membrane with the roots of the adjacent teeth, sinus septum, and the quality of subantral bone. Other conditions that occasionally may be observed in special situations are also explained. More than ten parameters should be checked in evaluating CBCT images of paranasal sinuses other than the width and the length of the residual ridge in the posterior region of the maxilla. Each of them may have a significant impact on the results of the open sinus lift surgery. PMID:26435632

  17. Relationship between maturation indices and morphology of the midpalatal suture obtained using cone-beam computed tomography images

    PubMed Central

    Jang, Hong-Ik; Kim, Sang-Cheol; Chae, Jong-Moon; Kang, Kyung-Hwa; Cho, Jin-Woo; Chang, Na-Young; Lee, Keun-Young

    2016-01-01

    Objective The purpose of this study was to determine whether predicting maturation of the midpalatal suture is possible by classifying its morphology on cone-beam computed tomography (CBCT) images and to investigate relationships with other developmental age indices. Methods The morphology of the midpalatal suture was assessed by using CBCT images of 99 patients. Axial plane images of the midpalatal suture were classified into five stages according to the classification scheme. To make the assessment more accurate, the morphology and fusion of the midpalatal suture were additionally investigated on coronal cross-sectional planar images and volume-rendered images. Bone age was evaluated using the hand and wrist method (HWM) and cervical vertebrae method (CVM); dental age (Hellman's index), sex, and chronological age were also assessed. To evaluate relationships among variables, Spearman's rho rank test was performed along with crosstabs using contingency coefficients. Results The HWM and CVM showed strong correlations with the maturation stage of the midpalatal suture, while other indices showed relatively weak correlations (p < 0.01). Through crosstabs, the HWM and CVM showed high association values with CBCT stage; the HWM demonstrated slightly higher values (p < 0.0001). Based on the HWM, the midpalatal suture was not fused until stage 6 in both sexes. Conclusions Among developmental age indices, the HWM and CVM showed strong correlations and high associations, suggesting that they can be useful in assessing maturation of the midpalatal suture. PMID:27896208

  18. Investigation of the effects of storage time on the dimensional accuracy of impression materials using cone beam computed tomography

    PubMed Central

    2016-01-01

    PURPOSE The storage conditions of impressions affect the dimensional accuracy of the impression materials. The aim of the study was to assess the effects of storage time on dimensional accuracy of five different impression materials by cone beam computed tomography (CBCT). MATERIALS AND METHODS Polyether (Impregum), hydrocolloid (Hydrogum and Alginoplast), and silicone (Zetaflow and Honigum) impression materials were used for impressions taken from an acrylic master model. The impressions were poured and subjected to four different storage times: immediate use, and 1, 3, and 5 days of storage. Line 1 (between right and left first molar mesiobuccal cusp tips) and Line 2 (between right and left canine tips) were measured on a CBCT scanned model, and time dependent mean differences were analyzed by two-way univariate and Duncan's test (α=.05). RESULTS For Line 1, the total mean difference of Impregum and Hydrogum were statistically different from Alginoplast (P<.05), while Zetaflow and Honigum had smaller discrepancies. Alginoplast resulted in more difference than the other impressions (P<.05). For Line 2, the total mean difference of Impregum was statistically different from the other impressions. Significant differences were observed in Line 1 and Line 2 for the different storage periods (P<.05). CONCLUSION The dimensional accuracy of impression material is clinically acceptable if the impression material is stored in suitable conditions. PMID:27826388

  19. Preliminary evaluation of the dosimetric accuracy of cone-beam computed tomography for cases with respiratory motion

    NASA Astrophysics Data System (ADS)

    Kim, Dong Wook; Bae, Sunhyun; Chung, Weon Kuu; Lee, Yoonhee

    2014-04-01

    Cone-beam computed tomography (CBCT) images are currently used for patient positioning and adaptive dose calculation; however, the degree of CBCT uncertainty in cases of respiratory motion remains an interesting issue. This study evaluated the uncertainty of CBCT-based dose calculations for a moving target. Using a phantom, we estimated differences in the geometries and the Hounsfield units (HU) between CT and CBCT. The calculated dose distributions based on CT and CBCT images were also compared using a radiation treatment planning system, and the comparison included cases with respiratory motion. The geometrical uncertainties of the CT and the CBCT images were less than 0.15 cm. The HU differences between CT and CBCT images for standard-dose-head, high-quality-head, normal-pelvis, and low-dose-thorax modes were 31, 36, 23, and 33 HU, respectively. The gamma (3%, 0.3 cm)-dose distribution between CT and CBCT was greater than 1 in 99% of the area. The gamma-dose distribution between CT and CBCT during respiratory motion was also greater than 1 in 99% of the area. The uncertainty of the CBCT-based dose calculation was evaluated for cases with respiratory motion. In conclusion, image distortion due to motion did not significantly influence dosimetric parameters.

  20. Cone Beam Computed Tomographic Analysis of the Shape, Height, and Location of the Mandibular Lingula in a Population of Children

    PubMed Central

    Sekerci, Ahmet Ercan; Cantekin, Kenan; Aydinbelge, Mustafa

    2013-01-01

     Objectives. This is the first study to identify and classify the different morphological shapes of the mandibular lingula (ML) in children using cone-beam computed tomography (CBCT). Material and Methods. A retrospective study was performed to evaluate the shape, height, and location of the ML in relation to the surrounding structures using CBCT images of mandibles obtained from 269 children. The shape of the ML was classified into triangular, truncated, nodular, or assimilated types. The location was determined by five distances. The height of the lingula was also measured from the lingular tip to the mandibular foramen. Results. A nodular shape of the ML was most commonly found (48.3%, n = 260) followed by truncated (23.4%, n = 126), assimilated (14.4%, n = 78), and triangular (13.7%, n = 74). The mean distance of ML from the anterior and posterior borders of mandibular ramus was 13.3 ± 2.3 mm and 10.2 ± 1.6 mm, respectively. In the majority of the mandibles studied, the ML was located above the occlusal plane. Conclusion. The present study provides new information to the literature concerning the shape, height, and location of the lingula in a Turkish pediatric population. This finding may assist clinicians to localize the lingula and avoid intraoperative complications. PMID:24490173

  1. Accuracy of Cone Beam Computed Tomography in Diagnosis and Treatment Planning of Periodontal Bone Defects: A Case Report

    PubMed Central

    Songa, Vajra Madhuri; Jampani, Narendra Dev; Babu, Venkateshwara; Buggapati, Lahari

    2014-01-01

    Diagnosis of periodontitis depend mostly on traditional two-dimensional (2-D) radiographic assessment. Regardless of efforts in improving reliability, present methods of detecting bone level changes over time or determining three-dimensional (3-D) architecture of osseous defects are lacking. To improve the diagnostic potential, an imaging modality which would give an undistorted 3-D vision of a tooth and surrounding structures is imperative. Cone beam computed tomography (CBCT) generates 3D volumetric images which provide axial, coronal and sagittal multi-planar reconstructed images without magnification and renders image guidance throughout the treatment phase. The purpose of this case report was to introduce the clinical application of a newly developed, CBCT system for detecting alveolar bone loss in 21-year-old male patient with periodontitis. To evaluate the bone defect we took an intraoral radiograph and performed CBCT scanning on mandibular left first molar tooth and compared their images. CBCT images of mandibular left first molar showed the extension of furcation involvement, its distal root is devoid of supporting bone and it has only lingual cortical plate which were not shown precisely by the conventional intraoral radiograph. So we consider that the use of latest adjuncts like CBCT is successful in diagnosing periodontal defects. PMID:25654049

  2. Root Canal Morphology of Permanent Maxillary and Mandibular Canines in Indian Population Using Cone Beam Computed Tomography

    PubMed Central

    Somalinga Amardeep, Nikhita; Raghu, Sandhya; Natanasabapathy, Velmurugan

    2014-01-01

    Aim. To investigate the root canal anatomy of single-rooted permanent maxillary and mandibular canines in an Indian population using cone beam computed tomography (CBCT). Methodology. A total of 250 permanent maxillary canines and 250 permanent mandibular canines were selected and scanned using CBCT. The root anatomy of each tooth was evaluated for the following parameters: the pattern of the root canals, anatomic length of the crown and the root, the presence of accessory canals, the shape of the access cavity, the position of the apical foramina, root diameter, and dentin thickness of the root. Results. Majority of the teeth had a Type I canal configuration in both maxillary canines (81.6%) and mandibular canines (79.6%). In maxillary canine the other canal patterns found were Type III (11.6%), Type II (2.8%), Type V (2%), Type XIX (1.2%), and Type IV (0.8%). In mandibular canines the various other canal patterns found were Type III (13.6%), Type II (3.2%), Type V (2%), and Type XIX (1.6%). Apical foramina were laterally positioned in the majority of the teeth, 70.4% and 65.6% in maxillary and mandibular canines, respectively. 12% of the maxillary canines and 12.8% of the mandibular canines had accessory canals. Conclusion. The root canal anatomy of permanent maxillary and mandibular canines varied widely in an Indian population. PMID:24895538

  3. Predictability of bone density at posterior mandibular implant sites using cone-beam computed tomography intensity values.

    PubMed

    Alkhader, Mustafa; Hudieb, Malik; Khader, Yousef

    2017-01-01

    The aim of this study was to investigate the predictability of bone density at posterior mandibular implant sites using cone-beam computed tomography (CBCT) intensity values. CBCT cross-sectional images for 436 posterior mandibular implant sites were selected for the study. Using Invivo software (Anatomage, San Jose, California, USA), two observers classified the bone density into three categories: low, intermediate, and high, and CBCT intensity values were generated. Based on the consensus of the two observers, 15.6% of sites were of low bone density, 47.9% were of intermediate density, and 36.5% were of high density. Receiver-operating characteristic analysis showed that CBCT intensity values had a high predictive power for predicting high density sites (area under the curve [AUC] =0.94, P < 0.005) and intermediate density sites (AUC = 0.81, P < 0.005). The best cut-off value for intensity to predict intermediate density sites was 218 (sensitivity = 0.77 and specificity = 0.76) and the best cut-off value for intensity to predict high density sites was 403 (sensitivity = 0.93 and specificity = 0.77). CBCT intensity values are considered useful for predicting bone density at posterior mandibular implant sites.

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

    PubMed Central

    Kaya-Büyükbayram, Işıl; Özalp, Şerife; Aydemir, Seda

    2014-01-01

    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. PMID:25530890

  5. Correlation between pain and degenerative bony changes on cone-beam computed tomography images of temporomandibular joints.

    PubMed

    Bae, SunMee; Park, Moon-Soo; Han, Jin-Woo; Kim, Young-Jun

    2017-12-01

    The aim of this study was to assess correlation between pain and degenerative bony changes on cone-beam computed tomography (CBCT) images of temporomandibular joints (TMJs). Two hundred eighty-three temporomandibular joints with degenerative bony changes were evaluated. Pain intensity (numeric rating scale, NRS) and pain duration in patients with degenerative joint disease (DJD) were also analyzed. We classified condylar bony changes on CBCT into five types: osteophyte (Osp), erosion (Ero), flattening (Fla), subchondral sclerosis (Scl), and pseudocyst (Pse). Degenerative bony changes were the most frequent in the age groups of 10~19, 20-29, and 50~59 years. The most frequent pain intensity was "none" (NRS 0, 34.6%) followed by "annoying" (NRS 3-5, 29.7%). The most frequent condylar bony change was Fla (219 joints, 77.4%) followed by Ero (169 joints, 59.7%). "Ero + Fla" was the most common combination of the bony changes (12.7%). The frequency of erosion was directly proportional to NRS, but the frequency of osteophyte was inversely proportional. The prevalence of Ero increased from onset until 2 years and gradually decreased thereafter. The prevalence of Osp, Ero, and Pse increased with age. Osp and Ero can be pain-related variables in degenerative joint disease (DJD) patients. "Six months to 2 years" may be a meaningful time point from the active, unstable phase to the stabilized late phase of DJD.

  6. Alveolar bone thickness around maxillary central incisors of different inclination assessed with cone-beam computed tomography.

    PubMed

    Tian, Yu-Lou; Liu, Fang; Sun, Hong-Jing; Lv, Pin; Cao, Yu-Ming; Yu, Mo; Yue, Yang

    2015-09-01

    To assess the labial and lingual alveolar bone thickness in adults with maxillary central incisors of different inclination by cone-beam computed tomography (CBCT). Ninety maxillary central incisors from 45 patients were divided into three groups based on the maxillary central incisors to palatal plane angle; lingual-inclined, normal, and labial-inclined. Reformatted CBCT images were used to measure the labial and lingual alveolar bone thickness (ABT) at intervals corresponding to every 1/10 of the root length. The sum of labial ABT and lingual ABT at the level of the root apex was used to calculate the total ABT (TABT). The number of teeth exhibiting alveolar fenestration and dehiscence in each group was also tallied. One-way analysis of variance and Tukey's honestly significant difference test were applied for statistical analysis. The labial ABT and TABT values at the root apex in the lingual-inclined group were significantly lower than in the other groups (p < 0.05). Lingual and labial ABT values were very low at the cervical level in the lingual-inclined and normal groups. There was a higher prevalence of alveolar fenestration in the lingual-inclined group. Lingual-inclined maxillary central incisors have less bone support at the level of the root apex and a greater frequency of alveolar bone defects than normal maxillary central incisors. The bone plate at the marginal level is also very thin.

  7. Segmentation of large periapical lesions toward dental computer-aided diagnosis in cone-beam CT scans

    NASA Astrophysics Data System (ADS)

    Rysavy, Steven; Flores, Arturo; Enciso, Reyes; Okada, Kazunori

    2008-03-01

    This paper presents an experimental study for assessing the applicability of general-purpose 3D segmentation algorithms for analyzing dental periapical lesions in cone-beam computed tomography (CBCT) scans. In the field of Endodontics, clinical studies have been unable to determine if a periapical granuloma can heal with non-surgical methods. Addressing this issue, Simon et al. recently proposed a diagnostic technique which non-invasively classifies target lesions using CBCT. Manual segmentation exploited in their study, however, is too time consuming and unreliable for real world adoption. On the other hand, many technically advanced algorithms have been proposed to address segmentation problems in various biomedical and non-biomedical contexts, but they have not yet been applied to the field of dentistry. Presented in this paper is a novel application of such segmentation algorithms to the clinically-significant dental problem. This study evaluates three state-of-the-art graph-based algorithms: a normalized cut algorithm based on a generalized eigen-value problem, a graph cut algorithm implementing energy minimization techniques, and a random walks algorithm derived from discrete electrical potential theory. In this paper, we extend the original 2D formulation of the above algorithms to segment 3D images directly and apply the resulting algorithms to the dental CBCT images. We experimentally evaluate quality of the segmentation results for 3D CBCT images, as well as their 2D cross sections. The benefits and pitfalls of each algorithm are highlighted.

  8. Open Sinus Lift Surgery and the Importance of Preoperative Cone-Beam Computed Tomography Scan: A Review.

    PubMed

    Rahpeyma, Amin; Khajehahmadi, Saeedeh

    2015-09-01

    Open sinus lift surgery is a form of pre-prosthetic surgery for increasing the quality and quantity of bone in the posterior region of the maxilla. Pre-operative assessment of the maxillary sinus is essential for the success of this surgery. PubMed search was carried out in English language literature for open sinus lift surgery and cone-beam computed tomography (CBCT). The results focused on anatomic variants, vascular anatomy, complications, osteotomy/ostectomy window dimensions and thickness of the Schneiderian Membrane. 59 articles were included in this review. Features other than the height and the width of the residual alveolar ridge that should be evaluated in preoperative CBCT scan include the thickness of the lateral maxillary sinus wall, the presence of the alveolar antral artery and its diameter, the maxillary sinus floor width and angulation, irregularity of sinus floor, intimate relation of Schneiderian membrane with the roots of the adjacent teeth, sinus septum, and the quality of subantral bone. Other conditions that occasionally may be observed in special situations are also explained. More than ten parameters should be checked in evaluating CBCT images of paranasal sinuses other than the width and the length of the residual ridge in the posterior region of the maxilla. Each of them may have a significant impact on the results of the open sinus lift surgery.

  9. Cone-beam computed tomography analysis of accessory maxillary ostium and Haller cells: Prevalence and clinical significance

    PubMed Central

    Sansare, Kaustubh; Karjodkar, Freny R.; Vanga, Kavita; Salve, Prashant; Pawar, Ajinkya M.

    2017-01-01

    Purpose This study aimed to evaluate the prevalence of Haller cells and accessory maxillary ostium (AMO) in cone-beam computed tomography (CBCT) images, and to analyze the relationships among Haller cells, AMO, and maxillary sinusitis. Materials and Methods Volumetric CBCT scans from 201 patients were retrieved from our institution's Digital Imaging and Communications in Medicine archive folder. Two observers evaluated the presence of Haller cells, AMO, and maxillary sinusitis in the CBCT scans. Results AMO was observed in 114 patients, of whom 27 (23.7%) had AMO exclusively on the right side, 26 (22.8%) only on the left side, and 61 (53.5%) bilaterally. Haller cells were identified in 73 (36.3%) patients. In 24 (32.9%) they were present exclusively on the right side, in 17 (23.3%) they were only present on the left side, and in 32 (43.8%) they were located bilaterally. Of the 73 (36.3%) patients with Haller cells, maxillary sinusitis was also present in 50 (68.5%). On using chi-square test, a significant association was observed between AMO and maxillary sinusitis in the presence of Haller cells. Conclusion Our results showed AMO and Haller cells to be associated with maxillary sinusitis. This study provides evidence for the usefulness of CBCT in imaging the bony anatomy of the sinonasal complex with significantly higher precision and a smaller radiation dose. PMID:28361027

  10. Comparative Evaluation of the Artefacts Index of Dental Materials on Two-Dimensional Cone-beam Computed Tomography

    PubMed Central

    Yuan, Fusong; Chen, Litong; Wang, Xiaofei; Wang, Yong; Lyu, Peijun; Sun, Yuchun

    2016-01-01

    The aim of the study was to propose the artefact index on cone-beam computed tomography (CBCT) images of clinical prosthodontics materials, and to compare the effect of the artefacts on CBCT image clarity of normal oral tissues. Seven spheres of different materials were secured on the centre of a resin baseboard, respectively, and four human molars in vitro were placed at 10 mm front, back, left and right of the sphere. The board was scanned using CBCT with the same setting. 10 tomographic images from each of the seven data sets with clear artefacts was selected. The grayscale measuring tool of Photoshop software was used to measure the grayscale (G0) within the boundary of tomographic image and the grayscales of the streaky artefacts that were 1 mm and 20 mm outside the circular boundary (G1 and G2). The arc length, L1, of the circular boundary with artefacts was measured; the circumference, L2, was calculated. The artefact index, A, was determined as (G1/G0) × 0.5 + (G2/G1) × 0.4 + (L2/L1) × 0.1. The artefact index A can comprehensively represent the effect of artefacts on CBCT image clarity for oral tissue. PMID:27185627

  11. Evaluation of the efficacy of a metal artifact reduction algorithm in different cone beam computed tomography scanning parameters.

    PubMed

    Queiroz, Polyane Mazucatto; Groppo, Francisco Carlos; Oliveira, Matheus Lima; Haiter-Neto, Francisco; Freitas, Deborah Queiroz

    2017-06-01

    The aim of this study was to evaluate the efficacy of a metal artifact reduction (MAR) algorithm in cone beam computed tomography (CBCT) images of dental materials obtained with different field-of-view (FOV) and voxel sizes. Two imaging phantoms were custom-made of acrylic resin. Each phantom had 3 cylinders made of the same dental material: dental amalgam or copper-aluminum alloy. CBCT scans were obtained separately for each of the imaging phantoms using the Picasso-Trio CBCT (Vatech, Hwaseong, Republic of Korea) unit at 4 FOV sizes and 2 voxel sizes. Each imaging phantom was scanned with and without MAR. All images were evaluated in the OnDemand3D software (Cybermed, Seoul, Republic of Korea) and image noise (gray value variability) was calculated as the standard deviation (SD) of the gray values of regions of interest around the dental material cylinders. Data were compared by the Friedman test and Dunn test (α = 0.05). Intraclass correlation coefficient (ICC) was calculated to assess intraobserver reliability. MAR significantly reduced (P < .05) image noise around the dental materials, irrespective of FOV and voxel sizes, with an ICC of 0.997. The efficacy of MAR was similar for the different FOV and voxel sizes studied. Hence, imaging protocols and the use of MAR algorithm should be based on the selection criteria. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Remodeling of Autogenous Bone Grafts after Osteotome Sinus Floor Elevation Assessed by Limited Cone Beam Computed Tomography

    PubMed Central

    Nishida, Tetsuya; Takenouchi, Yuka; Mori, Kyoko; Ariji, Miyuki; Nishida, Kaori; Ito, Koichi

    2013-01-01

    This study assessed the radiographic appearance of bone graft domes longitudinally after osteotome sinus floor elevation using cone beam computed tomography (CBCT). This study presents the radiological findings of a 6-month follow-up CBCT study in maxillary osteotome sinus floor elevation. We examined 52 patients with a crestal bone height of less than 8 mm in the posterior maxilla who required sinus augmentation. Implants (n = 91) were subsequently placed in regenerated bone following osteotome sinus floor elevation; autogenous bone was used as the augmentation material. In all cases, the grafted augmentation material tended to be absorbed, but at least 1 mm of grafted augmentation material was recognized around the implant fixtures on CBCT at the second implant operation. The border between the grafted augmentation material and the existing bone was indistinct. The grafted area apical to the implants undergoes shrinkage and remodeling. It was suggested that sufficient grafted autogenous bone changes into bone to support an implant. PMID:23956747

  13. Validation of cone beam computed tomography-based tooth printing using different three-dimensional printing technologies.

    PubMed

    Khalil, Wael; EzEldeen, Mostafa; Van De Casteele, Elke; Shaheen, Eman; Sun, Yi; Shahbazian, Maryam; Olszewski, Raphael; Politis, Constantinus; Jacobs, Reinhilde

    2016-03-01

    Our aim was to determine the accuracy of 3-dimensional reconstructed models of teeth compared with the natural teeth by using 4 different 3-dimensional printers. This in vitro study was carried out using 2 intact, dry adult human mandibles, which were scanned with cone beam computed tomography. Premolars were selected for this study. Dimensional differences between natural teeth and the printed models were evaluated directly by using volumetric differences and indirectly through optical scanning. Analysis of variance, Pearson correlation, and Bland Altman plots were applied for statistical analysis. Volumetric measurements from natural teeth and fabricated models, either by the direct method (the Archimedes principle) or by the indirect method (optical scanning), showed no statistical differences. The mean volume difference ranged between 3.1 mm(3) (0.7%) and 4.4 mm(3) (1.9%) for the direct measurement, and between -1.3 mm(3) (-0.6%) and 11.9 mm(3) (+5.9%) for the optical scan. A surface part comparison analysis showed that 90% of the values revealed a distance deviation within the interval 0 to 0.25 mm. Current results showed a high accuracy of all printed models of teeth compared with natural teeth. This outcome opens perspectives for clinical use of cost-effective 3-dimensional printed teeth for surgical procedures, such as tooth autotransplantation. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Augmented corticotomy-assisted presurgical orthodontics of class III malocclusions: a cephalometric and cone-beam computed tomography study.

    PubMed

    Wang, Bo; Shen, Guofang; Fang, Bing; Yu, Hongbo; Wu, Yong

    2013-11-01

    The purpose of this study was to evaluate mandibular incisor decompensation and the surrounding periodontal status with augmented corticotomy-assisted presurgical orthodontics of class III patients. Fifty-six surgical class III patients were enrolled in this study, 26 of whom chose augmented corticotomy-assisted presurgical orthodontics (G1), and 30 chose conventional procedures (G2). Cone-beam computed tomography images and lateral cephalograms were obtained from each patient before and after presurgical orthodontics. Measurements of variables were compared using Student t tests and separate variance estimation t tests. The amount of mandibular incisor decompensation and the increase in labial alveolar bone thickness in G1 were greater than those in G2 during presurgical orthodontics (P < 0.001), however, root resorption (P < 0.001), the decrease in lingual alveolar bone thickness (P < 0.001), and vertical alveolar bone loss on both labial (P < 0.05) and lingual sides (P < 0.001) were less in G1 than in G2. Sufficient mandibular incisor decompensation and better periodontal preservation were achieved with augmented corticotomy-assisted presurgical orthodontics for class III patients compared with traditional procedures.

  15. A cone beam computed tomographic evaluation of the size of the sella turcica in patients with cleft lip and palate.

    PubMed

    Paknahad, Maryam; Shahidi, Shoaleh; Khaleghi, Iman

    2017-09-01

    Changes in the size of the sella turcica are frequently related to pathologies and syndromes. The aim of this was to compare the sella turcica dimensions in patients with unilateral and bilateral cleft lip and palate and non-cleft subjects. Cone beam computed tomography (CBCT) images of three groups consisted of 20 patients with unilateral cleft lip and palate; 20 patients with bilateral cleft lip and palate and a control group consisting of 20 non-cleft subjects were the research population in this pilot study. The sella turcica linear dimensions in terms of length, depth and diameter were measured for all subjects. One-way ANOVA test was used to determine any significant differences among the three groups for the measured parameters. The length, depth and diameter of sella turcica were found to be significantly smaller in the unilateral and bilateral groups compared with the normal age and gender matched group. No significant differences were found in the measured variables between the unilateral and bilateral cleft patients. CBCT images showed a greater likelihood of abnormal sella turcica dimensions in patients with unilateral and bilateral cleft lip and palate. Therefore, the sella turcica dimensions may have an intrinsic relationship to the cleft condition.

  16. Accuracy of cone-beam computed tomography in defining spatial relationships between third molar roots and inferior alveolar nerve

    PubMed Central

    Pippi, Roberto; Santoro, Marcello; D’Ambrosio, Ferdinando

    2016-01-01

    Objective: Cone-beam computed tomography (CBCT) has been proposed in surgical planning of lower third molar extraction. The aim of the present study was to assess the reliability of CBCT in defining third molar root morphology and its spatial relationships with the inferior alveolar nerve (IAN). Materials and Methods: Intraoperative and radiographic variables of 74 lower third molars were retrospectively analyzed. Intraoperative variables included IAN exposure, number of roots, root morphology of extracted third molars, and presence/absence of IAN impression on the root surface. Radiographic variables included presence/absence of the cortex separating IAN from the third molar roots on CBCT examination, number of roots and root morphology on both orthopantomography (OPG) and CBCT. The statistical association between variables was evaluated using the Fisher's exact test. Results: In all cases of intraoperative IAN exposure, the cortex appeared discontinuous on CBCT images. All cases, in which the cortical bone was continuous on CBCT images, showed no association with nerve exposure. In all cases in which nerve impression was identified on the root surface, the IAN cortex showed interruptions on CBCT images. No nerve impression was identified in any of the cases, in which the cortex appeared continuous on CBCT images. CBCT also highlighted accessory roots and apical anomalies/curvatures, not visible on the OPG. Conclusions: CBCT seems to provide reliable and accurate information about the third molar root morphology and its relationship with the IAN. PMID:28042257

  17. A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model.

    PubMed

    Gowd, Snigdha; Shankar, T; Dash, Samarendra; Sahoo, Nivedita; Chatterjee, Suravi; Mohanty, Pritam

    2017-01-01

    The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t-test was performed to qualitatively evaluate the data and P < 0.05 was considered statistically significant. Statistically, significant results were obtained on data comparison between CBCT-derived images and plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis.

  18. Assessment of accessory canals of the canalis sinuosus: a study of 1000 cone beam computed tomography examinations.

    PubMed

    Machado, V de C; Chrcanovic, B R; Felippe, M B; Manhães Júnior, L R C; de Carvalho, P S P

    2016-12-01

    The aim of this study was to verify the presence, spatial location, and calibre of the accessory canals (AC) of the canalis sinuosus by cone beam computed tomography, and their relationship to the anterior maxilla. This retrospective analysis included the scans of 1000 subjects. Parameters registered were sex, age, number of AC, presence or absence of AC with a diameter <1.0mm, AC diameter (only for AC with a diameter >1.0mm), and AC location in relation to the adjacent teeth. Males showed a statistically higher frequency of AC than females. The difference in age distribution was not statistically significant. Twenty percent of all AC presented a diameter of a least 1.0mm. The end of the AC trajectory was most frequently located palatal to the anterior maxillary teeth. All relationships analyzed here were very weak (age vs. number of AC, age vs. AC diameter, number of AC vs. sex). Overall, the results of this study showed that AC of the canalis sinuosus are a common anatomical structure in the anterior maxilla, regardless of age and sex. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Three-dimensional cone beam computed tomography definition of the anatomical subregions of the upper airway: a validation study.

    PubMed

    Guijarro-Martínez, R; Swennen, G R J

    2013-09-01

    The exact boundaries of the upper airway subregions remain undefined. Consequently, anatomical limits vary greatly among different research groups and impede unbiased comparisons. The aim of this study was to provide clinical three-dimensional anatomical limits for the upper airway subregions, translate them into accurate and reliable cephalometric landmarks in cone beam computed tomography (CBCT) data, and validate the proposed measuring protocol. The upper airway of 40 normative individuals aged 23-35 years was evaluated with Dolphin Imaging(®) software. An appropriate grey-scale threshold value was pre-calculated. After adapting specific head positioning and virtual orientation protocols, the volume and minimum cross-sectional area of the nasopharynx, oropharynx, and hypopharynx, as previously defined by the authors, were calculated. Intra- and inter-observer reliability was excellent for volumes and moderate for areas. The sexual dimorphism analysis revealed a significantly greater oropharyngeal volume, hypopharyngeal volume, and minimum cross-sectional oropharyngeal area in males than in females. In conclusion, the proposed subregion definition showed technical feasibility and statistical reliability, especially for three-dimensional calculations. The reliability of two-dimensional calculations may be increased with improved head positioning during CBCT scanning and subsequent virtual head orientation. Standardization of the proposed anatomical limits has the potential to homogenize upper airway subregion analysis and permit comparisons among future studies. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Quantitative performance characterization of image quality and radiation dose for a CS 9300 dental cone beam computed tomography machine

    PubMed Central

    Abouei, Elham; Lee, Sierra; Ford, Nancy L.

    2015-01-01

    Abstract. This paper aims to characterize the radiation dose and image quality (IQ) performance of a dental cone beam computed tomography (CBCT) unit over a range of fields of view (FOV). IQ and dose were measured using a Carestream 9300 dental CBCT. Phantoms were positioned in the FOV to imitate clinical positioning. IQ was assessed by scanning a SEDENTEXCT IQ phantom, and images were analyzed in ImageJ. Dose index 1 was obtained using a thimble ionization chamber and SEDENTEXCT DI phantom. Mean gray values agreed within 93.5% to 99.7% across the images, with pixel-to-pixel fluctuations of 6% to 12.5%, with poorer uniformity and increased noise for child protocols. CNR was fairly constant across FOVs, with higher CNR for larger patient settings. The measured limiting spatial resolution agreed well with 10% MTF and bar pattern measurements. Dose was reduced for smaller patient settings within a given FOV; however, smaller FOVs obtained with different acquisition settings did not necessarily result in reduced dose. The use of patient-specific acquisition settings decreased the radiation dose for smaller patients, with minimal impact on the IQ. The full set of IQ and dose measurements is reported to allow dental professionals to compare the different FOV settings for clinical use. PMID:26587550

  1. Gender difference and root canal morphology in mandibular premolars: A cone-beam computed tomography study in an Iranian population

    PubMed Central

    Kazemipoor, Maryam; Hajighasemi, Afrooz; Hakimian, Roqayeh

    2015-01-01

    Background: Mandibular premolars are of the most difficult teeth to treat endodontically. Aims: To compare the root canal morphology of mandibular premolars between two genders in an Iranian population. Settings and Design: Totally, 230 cone-beam computed tomography images of the mandibles belonged to 115 males and 115 females were evaluated in the three spatial planes. Materials and Methods: The total number of roots and canals in the mandibular premolars was counted, and the difference between males and females were analyzed. Statistical Analysis: Data were analyzed using Chi-square test. The significance level was set as P < 0.05. Results: The majority of mandibular first and second premolars had one root (85.7% and 94.8%, respectively) and one canal (63.9% and 78.3%, respectively). The number of roots in the mandibular first premolars had statistically significant difference between two genders (P = 0.001). There was no significant difference between two genders in the number of roots (P = 0.208) and canals (P = 0.498) in the mandibular second premolars. Conclusion: According to the results of this study, the root canal morphology in the mandibular first premolars had statistically significant difference between two genders. PMID:26321843

  2. The impact of reorienting cone-beam computed tomographic images in varied head positions on the coordinates of anatomical landmarks

    PubMed Central

    Kim, Jae Hun; Hwang, Jae Joon; Lee, Jung-Hee

    2016-01-01

    Purpose The aim of this study was to compare the coordinates of anatomical landmarks on cone-beam computed tomographic (CBCT) images in varied head positions before and after reorientation using image analysis software. Materials and Methods CBCT images were taken in a normal position and four varied head positions using a dry skull marked with 3 points where gutta percha was fixed. In each of the five radiographic images, reference points were set, 20 anatomical landmarks were identified, and each set of coordinates was calculated. Coordinates in the images from the normally positioned head were compared with those in the images obtained from varied head positions using statistical methods. Post-reorientation coordinates calculated using a three-dimensional image analysis program were also compared to the reference coordinates. Results In the original images, statistically significant differences were found between coordinates in the normal-position and varied-position images. However, post-reorientation, no statistically significant differences were found between coordinates in the normal-position and varied-position images. Conclusion The changes in head position impacted the coordinates of the anatomical landmarks in three-dimensional images. However, reorientation using image analysis software allowed accurate superimposition onto the reference positions. PMID:27358821

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

    PubMed

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

    2013-11-01

    To compare the accuracy of linear and angular measurements between cephalometric and anatomic landmarks on surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols was the aim of this study. CBCT scans were made of cadaver heads and 3D surface models were created of the mandible using two different segmentation protocols. A high-resolution laser surface scanner was used to make a 3D model of the macerated mandibles. Twenty linear measurements at 15 anatomic and cephalometric landmarks between the laser surface scan and the 3D models generated from the two segmentation protocols (commercial segmentation (CS) and doctor's segmentation (DS) groups) were measured. The interobserver agreement for all the measurements of the all three techniques was excellent (intraclass correlation coefficient 0.97-1.00). The results are for both groups very accurate, but only for the measurements on the condyle and lingual part of the mandible, the measurements in the CS group is slightly more accurate than the DS group. 3D surface models produced by CBCT are very accurate but slightly inferior to reality when threshold-based methods are used. Differences in the segmentation process resulted in significant clinical differences between the measurements. Care has to be taken when drawing conclusions from measurements and comparisons made from different segmentations, especially at the condylar region and the lingual side of the mandible.

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

    PubMed

    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.

  5. Relationship between maxillary canine intra-alveolar position and maxillary incisor angulation: a cone beam computed tomography study.

    PubMed

    Baratieri, Carolina; Canongia, Ana Carolina Portes; Bolognese, Ana Maria

    2011-01-01

    The aims of the present study were to evaluate the angulation and inclination of permanent maxillary incisors and to correlate the results to the intra-alveolar permanent maxillary canine position during mixed dentition, using cone beam computed tomography (CBCT). The subjects were 30 children aged 7 to 10 years in the inter-transitory period of mixed dentition (permanent incisors and first molars erupted; primary canines, first and second molars erupted; and permanent canines intraosseous). The CBCT scans were obtained and, using the Dolphin Imaging(®) software - version 11.0, 3D images were reconstructed and the measurements were performed. The angulation of the right and left lateral and central maxillary incisors was measured in relation to the sagittal plane and their inclination was measured in relation to the coronal plane. The intra-alveolar height of the right and left maxillary canines was measured from the cusp tip to the axial plane. Pearson's correlation at 5% significance level showed positive correlation between the canine height and the lateral incisor angulation. It was concluded that the intra-alveolar position of the maxillary canines has a direct influence on the angulation of maxillary incisors, especially the lateral incisors.

  6. An evaluation of cone-beam computed tomography use in postgraduate orthodontic programs in the United States and Canada.

    PubMed

    Smith, Bradley R; Park, Jae Hyun; Cederberg, Robert A

    2011-01-01

    The purpose of this study was to evaluate the use of cone-beam computed tomography (CBCT) in postgraduate orthodontic residency programs. An anonymous electronic survey was sent to the program director/chair of each of the sixty-nine United States and Canadian postgraduate orthodontic programs, with thirty-six (52.2 percent) of these programs responding. Overall, 83.3 percent of programs reported having access to a CBCT scanner, while 73.3 percent reported regular usage. The vast majority (81.8 percent) used CBCT mainly for specific diagnostic purposes, while 18.2 percent (n=4) used CBCT as a diagnostic tool for every patient. Orthodontic residents received both didactic and practical (hands-on) training or solely didactic training in 59.1 percent and 31.8 percent of programs, respectively. Operation of the CBCT scanner was the responsibility of radiology technicians (54.4 percent), both radiology technicians and orthodontic residents (31.8 percent), and orthodontic residents alone (13.6 percent). Interpretation of CBCT results was the responsibility of a radiologist in 59.1 percent of programs, while residents were responsible for reading and referring abnormal findings in 31.8 percent of programs. Overall, postgraduate orthodontic program CBCT accessibility, usage, training, and interpretation were consistent in Eastern and Western regions, and most CBCT use was for specific diagnostic purposes of impacted/supernumerary teeth, craniofacial anomalies, and temporomandibular joint (TMJ) disorders.

  7. A C-Shaped Canal in a Maxillary Second Molar: Prexion 3D Cone-Beam Computed Tomography Analysis

    PubMed Central

    Lopes, Daniela Siqueira; Câmara, Andréa Cruz; do Nascimento, Monikelly do Carmo Chagas; Farias de Araújo, Luciane

    2016-01-01

    Objective: The aim of this study was to present an atypical case of a C-shaped root canal that was present in the vestibular root of a permanent maxillary second molar using PreXion 3-D cone-beam computed tomography (CBCT) as a diagnostic device. Materials and Methods: A 50-year-old female patient was referred for routine examination to a private diagnostic imaging clinic in Recife-Pernambuco. During the physical examination, the presence of an unusual C-shaped anatomy in the vestibular canal with a mesiodistal interconnection that extended from the apical to the cervical third was detected in axial slices acquired with a PreXion 3-D scanner. Results: Although C-shaped root canals are most frequently observed in the mandibular second molar, this case presented a rare finding in the permanent maxillary second molar. Conclusions: PreXion 3-D CBCT has emerged as a new high-resolution imaging test technology, thus assisting with the diagnosis of anatomical variations such as C-shaped root canals. However, such imaging technology is not recommended for routine use. PMID:28275283

  8. Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial.

    PubMed

    Pereira, Juliana da S; Jacob, Helder B; Locks, Arno; Brunetto, Mauricio; Ribeiro, Gerson L U

    2017-01-01

    The aim of this randomized clinical trial was to evaluate the dental, dentoalveolar, and skeletal changes occurring right after the rapid maxillary expansion (RME) and slow maxillary expansion (SME) treatment using Haas-type expander. All subjects performed cone-beam computed tomography (CBCT) before installation of expanders (T1) and right after screw stabilization (T2). Patients who did not follow the research parameters were excluded. The final sample resulted in 21 patients in RME group (mean age of 8.43 years) and 16 patients in SME group (mean age of 8.70 years). Based on the skewness and kurtosis statistics, the variables were judged to be normally distributed and paired t-test and student t-test were performed at significance level of 5%. Intermolar angle changed significantly due to treatment and RME showed greater buccal tipping than SME. RME showed significant changes in other four measurements due to treatment: maxilla moved forward and mandible showed backward rotation and, at transversal level both skeletal and dentoalveolar showed significant changes due to maxillary expansion. SME showed significant dentoalveolar changes due to maxillary expansion. Only intermolar angle showed significant difference between the two modalities of maxillary expansion with greater buccal tipping for RME. Also, RME produced skeletal maxillary expansion and SME did not. Both maxillary expansion modalities were efficient to promote transversal gain at dentoalveolar level. Sagittal and vertical measurements did not show differences between groups, but RME promoted a forward movement of the maxilla and backward rotation of the mandible.

  9. SICAT function: anatomical real-dynamic articulation by merging cone beam computed tomography and jaw motion tracking data.

    PubMed

    Hanssen, N; Ruge, S; Kordass, B

    2014-01-01

    Diagnostic imaging and jaw motion tracking are among the most important technologies used to document and assess the functional status of the stomatognathic system and to plan complex prosthetic restorations. However, the two technologies have not been used together until now. This article introduces SICAT Function (SICAT, Bonn, Germany), a new software application that directly combines and merges three-dimensional cone beam computed tomography (CBCT) and electronic jaw motion tracking (JMT) data. The software can also import digital impressions acquired with intraoral scanners and integrate them in functional movement displays. The result is an anatomically precise yet real-dynamic rendering of jaw movement, ready for comprehensive evaluation and analysis. Moreover, changes in the joint space (gap between the condyle and mandibular fossa) at defined mandibular resting positions or during mandibular movements can be directly measured and displayed. Only one CBCT scan is needed for patient-specific assessment of condylar positions (centric and therapeutic), which are displayed together with the joint space. All other positions are derived via correlation with electronic measurements.

  10. Analysis of the priority of anatomic structures according to the diagnostic task in cone-beam computed tomographic images

    PubMed Central

    2016-01-01

    Purpose This study was designed to evaluate differences in the required visibility of anatomic structures according to the diagnostic tasks of implant planning and periapical diagnosis. Materials and Methods Images of a real skull phantom were acquired under 24 combinations of different exposure conditions in a cone-beam computed tomography scanner (60, 70, 80, 90, 100, and 110 kV and 4, 6, 8,