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Sample records for helical cone-beam projections

  1. A BPF-FBP tandem algorithm for image reconstruction in reverse helical cone-beam CT.

    Science.gov (United States)

    Cho, Seungryong; Xia, Dan; Pellizzari, Charles A; Pan, Xiaochuan

    2010-01-01

    Reverse helical cone-beam computed tomography (CBCT) is a scanning configuration for potential applications in image-guided radiation therapy in which an accurate anatomic image of the patient is needed for image-guidance procedures. The authors previously developed an algorithm for image reconstruction from nontruncated data of an object that is completely within the reverse helix. The purpose of this work is to develop an image reconstruction approach for reverse helical CBCT of a long object that extends out of the reverse helix and therefore constitutes data truncation. The proposed approach comprises of two reconstruction steps. In the first step, a chord-based backprojection-filtration (BPF) algorithm reconstructs a volumetric image of an object from the original cone-beam data. Because there exists a chordless region in the middle of the reverse helix, the image obtained in the first step contains an unreconstructed central-gap region. In the second step, the gap region is reconstructed by use of a Pack-Noo-formula-based filteredback-projection (FBP) algorithm from the modified cone-beam data obtained by subtracting from the original cone-beam data the reprojection of the image reconstructed in the first step. The authors have performed numerical studies to validate the proposed approach in image reconstruction from reverse helical cone-beam data. The results confirm that the proposed approach can reconstruct accurate images of a long object without suffering from data-truncation artifacts or cone-angle artifacts. They developed and validated a BPF-FBP tandem algorithm to reconstruct images of a long object from reverse helical cone-beam data. The chord-based BPF algorithm was utilized for converting the long-object problem into a short-object problem. The proposed approach is applicable to other scanning configurations such as reduced circular sinusoidal trajectories.

  2. Motion tolerant iterative reconstruction algorithm for cone-beam helical CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hisashi; Goto, Taiga; Hirokawa, Koichi; Miyazaki, Osamu [Hitachi Medical Corporation, Chiba-ken (Japan). CT System Div.

    2011-07-01

    We have developed a new advanced iterative reconstruction algorithm for cone-beam helical CT. The features of this algorithm are: (a) it uses separable paraboloidal surrogate (SPS) technique as a foundation for reconstruction to reduce noise and cone-beam artifact, (b) it uses a view weight in the back-projection process to reduce motion artifact. To confirm the improvement of our proposed algorithm over other existing algorithm, such as Feldkamp-Davis-Kress (FDK) or SPS algorithm, we compared the motion artifact reduction, image noise reduction (standard deviation of CT number), and cone-beam artifact reduction on simulated and clinical data set. Our results demonstrate that the proposed algorithm dramatically reduces motion artifacts compared with the SPS algorithm, and decreases image noise compared with the FDK algorithm. In addition, the proposed algorithm potentially improves time resolution of iterative reconstruction. (orig.)

  3. Increasing Cone-beam projection usage by temporal fitting

    DEFF Research Database (Denmark)

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

    2010-01-01

    A Cone-beam CT system can be used to image the lung region. The system records 2D projections which will allow 3D reconstruction however a reconstruction based on all projections will lead to a blurred reconstruction in regions were respiratory motion occur. To avoid this the projections are typi...... on Poisons assumptions using an L-BFGS-B optimizer [5]. It will be demonstrated on a phantom data set that the information gained from a 4D model leads to smaller reconstruction errors than a 3D iterative reconstruction based on phase binned data.......A Cone-beam CT system can be used to image the lung region. The system records 2D projections which will allow 3D reconstruction however a reconstruction based on all projections will lead to a blurred reconstruction in regions were respiratory motion occur. To avoid this the projections...... in [6] prior knowledge of the lung deformation estimated from the planning CT could be used to include all projections into the reconstruction. It has also been attempted to estimate both the motion and 3D volume simultaneously in [4]. Problems with motion estimation are ill-posed leading to suboptimal...

  4. Extracting respiratory signals from thoracic cone beam CT projections

    CERN Document Server

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

    2012-01-01

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

  5. Fundamental efficiency of new-style limited-cone-beam CT (3DX). Comparison with helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Kazuya; Arai, Yoshinori; Iwai, Kazuo; Hashimoto, Koji; Shinoda, Koji [Nihon Univ., Tokyo (Japan). School of Dentistry; Saitou, Tsutomu

    2000-12-01

    Limited-cone-beam CT named 'Ortho-CT' has been used clinically for more than 2 years. On the basis of this experience we developed the new-style limited-cone-beam CT for practical use named '3DX Multi image micro CT' (3DX). Purpose of this study was to evaluate the fundamental efficiency of this new-style limited-cone-beam CT in comparison with helical-CT. The resolutions of 3DX was evaluated with MTF (Modulation transfer function). 3DX were compared with helical CT about the fundamental efficiency. The subjective image quality was evaluated with the anatomical landmarks which included inner ear, temporomandibular joint (TMJ), and the maxillary first molar and mandibular first molar. Five dental radiologists and two otolaryngologists evaluated the quality of 3DX image in comparison with that of helical CT images on the same observation point. The five-point scale used ranged from point one (inferior) to five (superior). The skin doses of 3DX and helical CT were measured using TLD on the Rando phantom. The resolution of 3DX was 3.1 line pair/mm (horizontal) and 4.2 line pair/mm (vertical). The subjective image quality of 3DX was better than that of helical CT at every observational point. The minimum score was 3.46 and maximum score was 4.03. There was a significant difference in every observation point (p<0.05). The skin doses were 1.19 mSv with 3DX and 160.0 mSv with helical CT. The skin dose of 3DX was very low compared with that of helical CT. The image showed very high resolution in comparison with that of helical CT. The skin dose was under the one-percent as against helical CT. This system is very useful for diagnosis of tooth and bone in dental and otological field. (author)

  6. Cone-beam CT in paediatric dentistry: DIMITRA project position statement.

    Science.gov (United States)

    Oenning, Anne Caroline; Jacobs, Reinhilde; Pauwels, Ruben; Stratis, Andreas; Hedesiu, Mihaela; Salmon, Benjamin

    2018-03-01

    DIMITRA (dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks) is a European multicenter and multidisciplinary project focused on optimizing cone-beam CT exposures for children and adolescents. With increasing use of cone-beam CT for dentomaxillofacial diagnostics, concern arises regarding radiation risks associated with this imaging modality, especially for children. Research evidence concerning cone-beam CT indications in children remains limited, while reports mention inconsistent recommendations for dose reduction. Furthermore, there is no paper using the combined and integrated information on the required indication-oriented image quality and the related patient dose levels. In this paper, therefore, the authors initiate an integrated approach based on current evidence regarding image quality and dose, together with the expertise of DIMITRA's members searching for a state of the art. The aim of this DIMITRA position statement is to provide indication-oriented and patient-specific recommendations regarding the main cone-beam CT applications in the pediatric field. The authors will review this position statement document when results regarding multidisciplinary approaches evolve, in a period of 5 years or earlier.

  7. Automatic tracking of implanted fiducial markers in cone beam CT projection images

    OpenAIRE

    Marchant, T.E.; Skalski, A.; Matuszewski, B. J.

    2012-01-01

    Purpose: This paper describes a novel method for simultaneous intrafraction tracking of multiple fiducial markers. Although the proposed method is generic and can be adopted for a number of applications including fluoroscopy based patient position monitoring and gated radiotherapy, the tracking results presented in this paper are specific to tracking fiducial markers in a sequence of cone beam CT projection images. Methods: The proposed method is accurate and robust thanks to utilizing the me...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-15

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

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

    CERN Document Server

    Jones, Bernard L; Miften, Moyed

    2015-01-01

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

  10. Projection matrix acquisition for cone-beam computed tomography iterative reconstruction

    Science.gov (United States)

    Yang, Fuqiang; Zhang, Dinghua; Huang, Kuidong; Shi, Wenlong; Zhang, Caixin; Gao, Zongzhao

    2017-02-01

    Projection matrix is an essential and time-consuming part in computed tomography (CT) iterative reconstruction. In this article a novel calculation algorithm of three-dimensional (3D) projection matrix is proposed to quickly acquire the matrix for cone-beam CT (CBCT). The CT data needed to be reconstructed is considered as consisting of the three orthogonal sets of equally spaced and parallel planes, rather than the individual voxels. After getting the intersections the rays with the surfaces of the voxels, the coordinate points and vertex is compared to obtain the index value that the ray traversed. Without considering ray-slope to voxel, it just need comparing the position of two points. Finally, the computer simulation is used to verify the effectiveness of the algorithm.

  11. A GPU Tool for Efficient, Accurate, and Realistic Simulation of Cone Beam CT Projections

    CERN Document Server

    Jia, Xun; Cervino, Laura; Folkerts, Michael; Jiang, Steve B

    2012-01-01

    Simulation of x-ray projection images plays an important role in cone beam CT (CBCT) related research projects. A projection image contains primary signal, scatter signal, and noise. It is computationally demanding to perform accurate and realistic computations for all of these components. In this work, we develop a package on GPU, called gDRR, for the accurate and efficient computations of x-ray projection images in CBCT under clinically realistic conditions. The primary signal is computed by a tri-linear ray-tracing algorithm. A Monte Carlo (MC) simulation is then performed, yielding the primary signal and the scatter signal, both with noise. A denoising process is applied to obtain a smooth scatter signal. The noise component is then obtained by combining the difference between the MC primary and the ray-tracing primary signals, and the difference between the MC simulated scatter and the denoised scatter signals. Finally, a calibration step converts the calculated noise signal into a realistic one by scali...

  12. A Projection Quality-Driven Tube Current Modulation Method in Cone-Beam CT for IGRT: Proof of Concept.

    Science.gov (United States)

    Men, Kuo; Dai, Jianrong

    2017-12-01

    To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it was used to simulate different attenuation (μ). Projections were acquired with a series of tube current-exposure time product (mAs) settings, and a 2-dimensional contrast to noise ratio was analyzed for each projection to create a lookup table of mAs versus 2-dimensional contrast to noise ratio, μ. Before a patient underwent computed tomography, the maximum attenuation [Formula: see text] within the 95% range of each projection angle (θ) was estimated according to the planning computed tomography images. Then, a desired 2-dimensional contrast to noise ratio value was selected, and the mAs setting at θ was calculated with the lookup table of mAs versus 2-dimensional contrast to noise ratio,[Formula: see text]. Three-dimensional cone-beam computed tomography images were reconstructed using the projections acquired with the selected mAs. The imaging dose was evaluated with a polymethyl methacrylate dosimetry phantom in terms of volume computed tomography dose index. Image quality was analyzed using a Catphan 503 phantom with an oval body annulus and a pelvis phantom. For the Catphan 503 phantom, the cone-beam computed tomography image obtained by the projection quality-driven tube current modulation method had a similar quality to that of conventional cone-beam computed tomography . However, the proposed method could reduce the imaging dose by 16% to 33% to achieve an equivalent contrast to noise ratio value. For the pelvis phantom, the structural similarity index was 0.992 with a dose reduction of 39.7% for the projection quality-driven tube current modulation method. The proposed method could reduce the

  13. Lung tumor tracking, trajectory reconstruction, and motion artifact removal using rotational cone-beam projections

    Science.gov (United States)

    Lewis, John Henry

    Management of lung tumor motion is a challenging and important problem for modern, highly conformal radiotherapy. Poorly managed tumor motion can lead to imaging artifacts, poor target coverage, and unnecessarily high dose to normal tissues. The goals of this dissertation are to develop a real-time localization algorithm that is applicable to rotational cone-beam projections acquired during regular (˜60 seconds) cone-beam computed tomography (CBCT) scans, and to use these tracking results to reconstruct a tumor's trajectory, shape and size immediately prior to treatment. Direct tumor tracking is performed via a multiple template matching algorithm where templates are derived from digitally reconstructed radiographs (DRRs) generated from four-dimensional computed tomography (4DCT). Three-dimensional (3D) tumor trajectories are reconstructed by binning twodimensional (2D) tracking results according to their corresponding respiratory phases. Within each phase bin a point is calculated approximating the 3D tumor position, resulting in a 3D phase-binned trajectory. These 3D trajectories are used to construct motion blurring functions which are in turn used to remove motion blurring artifacts from reconstructed CBCT volumes with a deconvolution algorithm. Finally, the initial direct tracking algorithm is combined with diaphragm-based tracking to develop a more robust "combined" tracking algorithm. Respiratory motion phantoms (digital and physical), and example patient cases were used to test each technique. Direct tumor tracking performed well for both phantom cases, with sub-millimeter root mean square error (e rms) in the axial and tangential imager dimensions. In patient studies the algorithm performed well for many angles, but exhibited large errors for some projections. Accurate 3D trajectories were successfully reconstructed for patients and phantoms. Errors in reconstructed trajectories were smaller than the errors in the direct tracking results in all cases. The

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

    Science.gov (United States)

    Wan, Hanlin; Bertholet, Jenny; Ge, Jiajia; Poulsen, Per; Parikh, Parag

    2016-03-01

    In radiation therapy, fiducial markers are often implanted near tumors and used for patient positioning and respiratory gating purposes. These markers are then used to manually align the patients by matching the markers in the cone beam computed tomography (CBCT) reconstruction to those in the planning CT. This step is time-intensive and user-dependent, and often results in a suboptimal patient setup. We propose a fully automated, robust method based on dynamic programming (DP) for segmenting radiopaque fiducial markers in CBCT projection images, which are then used to automatically optimize the treatment couch position and/or gating window bounds. The mean of the absolute 2D segmentation error of our DP algorithm is 1.3+/- 1.0 mm for 87 markers on 39 patients. Intrafraction images were acquired every 3 s during treatment at two different institutions. For gated patients from Institution A (8 patients, 40 fractions), the DP algorithm increased the delivery accuracy (96+/- 6% versus 91+/- 11% , p  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.

  15. Accuracy of intraoral radiography, multidetector helical CT, and limited cone-beam CT for the detection of horizontal tooth root fracture.

    Science.gov (United States)

    Iikubo, Masahiro; Kobayashi, Kaoru; Mishima, Akira; Shimoda, Shinji; Daimaruya, Takayoshi; Igarashi, Chinami; Imanaka, Masahiro; Yuasa, Masao; Sakamoto, Maya; Sasano, Takashi

    2009-11-01

    The accuracies of intraoral radiography (IOR), multidetector helical computerized tomography (MDHCT) at slice thicknesses 0.63 mm and 1.25 mm, and limited cone-beam computerized tomography (LCBCT) were compared for detection of horizontal tooth root fracture. In 7 beagle dogs, 28 maxillary anterior teeth were used, of which 13 had artificially induced horizontal root fracture. The specimens were examined by the above-mentioned 4 modalities. Diagnosis of root fracture was based on direct visualization of radiolucent line in each image by 6 radiologists. Sensitivity, negative predictive value, and diagnostic accuracy (true positives + true negatives) for detecting fracture lines in LCBCT (0.96 +/- 0.04, 0.97 +/- 0.03, 0.93 +/- 0.04, respectively) were significantly higher than MDHCT at 0.63 mm (0.76 +/- 0.09, 0.8 +/- 0.05, 0.8 +/- 0.05, respectively), MDHCT at 1.25 mm (0.49 +/- 0.09, 0.66 +/- 0.04, 0.69 +/- 0.05, respectively), and IOR (0.51 +/- 0.18, 0.67 +/- 0.08, 0.69 +/- 0.08, respectively). Specificity and positive predictive value showed no significant intermethod difference among the 4 modalities. Limited cone-beam CT is more useful than the other 3 radiographic modalities for diagnostic imaging of horizontal tooth root fracture.

  16. 3D localization of electrophysiology catheters from a single x-ray cone-beam projection

    Energy Technology Data Exchange (ETDEWEB)

    Robert, Normand, E-mail: normand.robert@sri.utoronto.ca; Polack, George G.; Sethi, Benu; Rowlands, John A. [Physical Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada); Crystal, Eugene [Division of Cardiology, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada)

    2015-10-15

    Purpose: X-ray images allow the visualization of percutaneous devices such as catheters in real time but inherently lack depth information. The provision of 3D localization of these devices from cone beam x-ray projections would be advantageous for interventions such as electrophysiology (EP), whereby the operator needs to return a device to the same anatomical locations during the procedure. A method to achieve real-time 3D single view localization (SVL) of an object of known geometry from a single x-ray image is presented. SVL exploits the change in the magnification of an object as its distance from the x-ray source is varied. The x-ray projection of an object of interest is compared to a synthetic x-ray projection of a model of said object as its pose is varied. Methods: SVL was tested with a 3 mm spherical marker and an electrophysiology catheter. The effect of x-ray acquisition parameters on SVL was investigated. An independent reference localization method was developed to compare results when imaging a catheter translated via a computer controlled three-axes stage. SVL was also performed on clinical fluoroscopy image sequences. A commercial navigation system was used in some clinical image sequences for comparison. Results: SVL estimates exhibited little change as x-ray acquisition parameters were varied. The reproducibility of catheter position estimates in phantoms denoted by the standard deviations, (σ{sub x}, σ{sub y}, σ{sub z}) = (0.099 mm,  0.093 mm,  2.2 mm), where x and y are parallel to the detector plane and z is the distance from the x-ray source. Position estimates (x, y, z) exhibited a 4% systematic error (underestimation) when compared to the reference method. The authors demonstrated that EP catheters can be tracked in clinical fluoroscopic images. Conclusions: It has been shown that EP catheters can be localized in real time in phantoms and clinical images at fluoroscopic exposure rates. Further work is required to characterize

  17. An Inter-Projection Interpolation (IPI) Approach with Geometric Model Restriction to Reduce Image Dose in Cone Beam CT (CBCT)

    Science.gov (United States)

    Zhang, Hong; Kong, Fengchong; Ren, Lei; Jin, Jian-Yue

    2015-01-01

    Cone beam computed tomography (CBCT) imaging is a key step in image guided radiation therapy (IGRT) to improve tumor targeting. The quality and imaging dose of CBCT are two important factors. However, X-ray scatter in the large cone beam field usually induces image artifacts and degrades the image quality for CBCT. A synchronized moving grid (SMOG) approach has recently been proposed to resolve this issue and shows great promise. However, the SMOG technique requires two projections in the same gantry angle to obtain full information due to signal blockage by the grid. This study aims to develop an inter-projection interpolation (IPI) method to estimate the blocked image information. This approach will require only one projection in each gantry angle, thus reducing the scan time and patient dose. IPI is also potentially suitable for sparse-view CBCT reconstruction to reduce the imaging dose. To be compared with other state-of-the-art spatial interpolation (called inpainting) methods in terms of signal-to-noise ratio (SNR) on a Catphan and head phantoms, IPI increases SNR from 15.3dB and 12.7dB to 29.0dB and 28.1dB, respectively. The SNR of IPI on sparse-view CBCT reconstruction can achieve from 28dB to 17dB for undersample projection sets with gantry angle interval varying from 1 to 3 degrees for both phantoms. PMID:26005721

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

    Directory of Open Access Journals (Sweden)

    Toru Ishikawa

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

  19. Image artifacts and noise reduction algorithm for cone-beam computed tomography with low-signal projections.

    Science.gov (United States)

    Yang, Fu-Qiang; Zhang, Ding-Hua; Huang, Kui-Dong; Yang, Ya-Fei; Liao, Jin-Ming

    2017-10-10

    This study aims to investigate and test a new image reconstruction algorithm applying to the low-signal projections to generate high quality images by reducing the artifacts and noise in the cone-beam computed tomography (CBCT). For the low-signal and noisy projections, a multiple sampling method is first utilized in projection domain to suppress environmental noise, which guarantees the accuracy of the data for reconstruction, simultaneously. Next, a fuzzy entropy based method with block matching 3D (BM3D) filtering algorithm is employed to improve the image quality to reduce artifacts and noise in image domain. Then, simulation studies on polychromatic spectrum were performed to evaluate the performance of the proposed new algorithm. Study results demonstrated significant improvement in the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of the images reconstructed using the new algorithm. SNRs and CNRs of the new images were averagely 40% and 20% higher than those of the previous images reconstructed using the traditional algorithms, respectively. As a result, since the new image reconstruction algorithm effectively reduced the artifacts and noise, and produced images with better contour and grayscale distribution, it has the potential to improve image quality using the original CBCT data with the low and missing signals.

  20. GPU-based Fast Cone Beam CT Reconstruction from Undersampled and Noisy Projection Data via Total Variation

    CERN Document Server

    Jia, Xun; Li, Ruijiang; Song, William Y; Jiang, Steve B

    2010-01-01

    Cone-beam CT (CBCT) plays an important role in image guided radiation therapy (IGRT). However, the large radiation dose from serial CBCT scans in most IGRT procedures raises a clinical concern, especially for pediatric patients who are essentially excluded from receiving IGRT for this reason. To lower the imaging dose, we have developed a fast GPU-based CBCT reconstruction algorithm. The CBCT is reconstructed by minimizing an energy functional consisting of a data fidelity term and a total variation regularization term. We developed a GPU-friendly version of the forward-backward splitting algorithm to solve this model. Multi-grid technique is also employed. It is found that 20~40 x-ray projections are sufficient to reconstruct images with satisfactory quality for IGRT. The reconstruction time ranges from 77 to 130 sec on a NVIDIA Tesla C1060 GPU card, depending on the number of projections used, which is estimated about 100 times faster than similar iterative reconstruction approaches. Moreover, phantom studi...

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

    DEFF Research Database (Denmark)

    Wan, Hanlin; Bertholet, Jenny; Ge, Jiajia

    2016-01-01

    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 [Formula: see text] 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...

  2. Fully automatic segmentation of arbitrarily shaped fiducial markers in cone-beam CT projections

    DEFF Research Database (Denmark)

    Bertholet, Jenny; Wan, Hanlin; Toftegaard, Jakob

    2017-01-01

    segmentation, the DPTB algorithm generates and uses a 3D marker model to create 2D templates at any projection angle. The 2D templates are used to segment the marker position as the position with highest normalized cross-correlation in a search area centered at the DP segmented position. The accuracy of the DP...... algorithm and the new DPTB algorithm was quantified as the 2D segmentation error (pixels) compared to a manual ground truth segmentation for 97 markers in the projection images of CBCT scans of 40 patients. Also the fraction of wrong segmentations, defined as 2D errors larger than 5 pixels, was calculated....... The mean 2D segmentation error of DP was reduced from 4.1 pixels to 3.0 pixels by DPTB, while the fraction of wrong segmentations was reduced from 17.4% to 6.8%. DPTB allowed rejection of uncertain segmentations as deemed by a low normalized cross-correlation coefficient and contrast-to-noise ratio...

  3. Low-contrast visualization in megavoltage cone-beam CT at one beam pulse per projection using thick segmented scintillators

    Science.gov (United States)

    El-Mohri, Youcef; Antonuk, Larry E.; Zhao, Qihua; Choroszucha, Richard B.; Wang, Yi

    2010-04-01

    Megavoltage cone-beam computed tomography (MV CBCT) using an electronic portal imaging device (EPID) is a highly promising technique for providing valuable volumetric information for image guidance in radiotherapy. However, active matrix flat-panel imagers (AMFPIs), which are the established gold standard in portal imaging, require a relatively large dose to create images that are clinically useful. This is a consequence of the inefficiency of the phosphor screens employed in conventional MV AMFPIs, which utilize only ~2% of the incident radiation at 6 MV. Fortunately, the incorporation of thick, segmented scintillators can significantly improve the performance of MV AMFPIs, leading to improved image quality for projection imaging at extremely low dose. It is therefore of interest to explore the performance of such thick scintillators for MV CBCT toward the goal of soft-tissue contrast visualization. In this study, prototype AMFPIs incorporating segmented scintillators based on CsI:Tl and BGO crystals with thicknesses ranging from ~11 to 25 mm have been constructed and evaluated. Each prototype incorporates a detector consisting of a matrix of 120 × 60 scintillator elements separated by reflective septal walls, with an element-to-element pitch of 1.016 mm, coupled to an overlying ~1 mm thick Cu plate. The prototype AMFPIs were incorporated into a bench-top CBCT system, allowing the acquisition of tomographic images of a contrast phantom using a 6 MV radiotherapy photon beam. The phantom consists of a water-equivalent (solid water) cylinder, embedded with tissue-equivalent inserts having electron densities, relative to water, varying from ~0.43 to ~1.47. Reconstructed images of the phantom were obtained down to the lowest available dose (one beam pulse per projection), corresponding to a total scan dose of ~4 cGy using 180 projections. In this article, reconstructed images, contrast, noise and contrast-to-noise ratio for the tissue-equivalent objects using the

  4. Large Helical Device project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    In this book, the results of the scientific research on the design, trial manufacture and manufacturing processes of the Large Helical Device which was constructed in National Institute for Fusion Science are summarized. The LHD is the largest helical device in the world, and the largest superconducting system in the world. It possesses the following features: the optimization of heliotron magnetic field coordination, the adoption of superconducting magnets for 2 helical magnetic field coils and 6 poloidal coils, the adoption of helical diverter which enables steady plasma experiment, the flexible specification as the experimental facility and so on. The construction has been carried out smoothly, and in March, 1998, first plasma was generated. The outline of the Large Helical Device project, the physical design, the equipment design, the research and development of superconductivity and low temperature system, the design and manufacture of the superconducting and low temperature systems, the design and manufacture of the power source and superconducting bus-line, vacuum vessel and others, electron cyclotron heating, neutral beam injection and ion cyclotron RF heating, measurement system, control and data processing, safety management, the theory and analysis of LHD plasma, the visualization of the result of theoretical analysis, the analysis of the experimental data, and the experiment plan are described. (K.I.)

  5. Binary moving-blocker-based scatter correction in cone-beam computed tomography with width-truncated projections: proof of concept

    Science.gov (United States)

    Lee, Ho; Fahimian, Benjamin P.; Xing, Lei

    2017-03-01

    This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, 1D B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions. The scatter map of the unblocked projections is corrected by averaging two scatter maps that correspond to their adjacent blocked projections. The scatter-corrected projections are obtained by subtracting the corresponding scatter maps from the projection data and are utilized to generate the CBCT image by a compressed-sensing (CS)-based iterative reconstruction algorithm. Catphan504 and pelvis phantoms were used to evaluate the method’s performance. The proposed BMB-based technique provided an effective method to enhance the image quality by suppressing scatter-induced artifacts, such as ring artifacts around the bowtie area. Compared to CBCT without a blocker, the spatial nonuniformity was reduced from 9.1% to 3.1%. The root-mean-square error of the CT numbers in the regions of interest (ROIs) was reduced from 30.2 HU to 3.8 HU. In addition to high resolution, comparable to that of the benchmark image, the CS-based reconstruction also led to a better contrast-to-noise ratio in seven ROIs. The proposed technique enables complete scatter-corrected CBCT imaging with width-truncated projections and allows reducing the acquisition time to approximately half. This work may have significant implications for image-guided or adaptive radiation therapy, where CBCT is often used.

  6. Dual energy approach for cone beam artifacts correction

    Science.gov (United States)

    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.

  7. Optimization of Cone Beam CT Reconstruction Algorithm Based on CUDA

    National Research Council Canada - National Science Library

    Wang Li-Fang; Zhang Shu-Hai

    2013-01-01

    .... This paper optimizes cone beam CT reconstruction algorithm by CUDA and improves the speed of weighted back-projection and filtering, and shortens the data access time by using the texture memory...

  8. Image quality in thoracic 4D cone-beam CT: A sensitivity analysis of respiratory signal, binning method, reconstruction algorithm, and projection angular spacing

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, Chun-Chien [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006, Australia and Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia); Kipritidis, John; O’Brien, Ricky T.; Keall, Paul J., E-mail: paul.keall@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006 (Australia); Kuncic, Zdenka [Institute of Medical Physics, School of Physics, University of Sydney, NSW 2006 (Australia)

    2014-04-15

    Purpose: Respiratory signal, binning method, and reconstruction algorithm are three major controllable factors affecting image quality in thoracic 4D cone-beam CT (4D-CBCT), which is widely used in image guided radiotherapy (IGRT). Previous studies have investigated each of these factors individually, but no integrated sensitivity analysis has been performed. In addition, projection angular spacing is also a key factor in reconstruction, but how it affects image quality is not obvious. An investigation of the impacts of these four factors on image quality can help determine the most effective strategy in improving 4D-CBCT for IGRT. Methods: Fourteen 4D-CBCT patient projection datasets with various respiratory motion features were reconstructed with the following controllable factors: (i) respiratory signal (real-time position management, projection image intensity analysis, or fiducial marker tracking), (ii) binning method (phase, displacement, or equal-projection-density displacement binning), and (iii) reconstruction algorithm [Feldkamp–Davis–Kress (FDK), McKinnon–Bates (MKB), or adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS)]. The image quality was quantified using signal-to-noise ratio (SNR), contrast-to-noise ratio, and edge-response width in order to assess noise/streaking and blur. The SNR values were also analyzed with respect to the maximum, mean, and root-mean-squared-error (RMSE) projection angular spacing to investigate how projection angular spacing affects image quality. Results: The choice of respiratory signals was found to have no significant impact on image quality. Displacement-based binning was found to be less prone to motion artifacts compared to phase binning in more than half of the cases, but was shown to suffer from large interbin image quality variation and large projection angular gaps. Both MKB and ASD-POCS resulted in noticeably improved image quality almost 100% of the time relative to FDK. In addition, SNR

  9. SU-D-12A-01: An Inter-Projection Interpolation (IPI) Approach for the Synchronized Moving Grid (SMOG) to Reduce Dose in Cone Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H; Kong, V; Jin, J [Georgia Regents University, Augusta, GA (Georgia); Ren, L [Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: Synchronized moving grid is a promising technique to reduce scatter and ghost artifacts in cone beam computed tomography (CBCT). However, it requires 2 projections in the same gantry angle to obtain full information due to signal blockage by the grid. We proposed an inter-projection interpolation (IPI) method to estimate blocked signals, which may reduce the scan time and the dose. This study aims to provide a framework to achieve a balance between speed, dose and image quality. Methods: The IPI method is based on the hypothesis that an abrupt signal in a projection can be well predicted by the information in the two immediate neighboring projections if the gantry angle step is small. The study was performed on a Catphan and a head phantom. The SMOG was simulated by erasing the information (filling with “0”) of the areas in each projection corresponding to the grid. An IPI algorithm was applied on each projection to recover the erased information. FDK algorithm was used to reconstruct CBCT images for the IPI-processed projections, and compared with the original image in term of signal to noise ratio (SNR) measured in the whole reconstruction image range. The effect of gantry angle step was investigated by comparing the CBCT images from projection sets of various gantry intervals, with IPI-predicted projections to fill the missing projection in the interval. Results: The IPI procession time was 1.79s±0.53s for each projection. SNR after IPI was 29.0db and 28.1db for the Catphan and head phantom, respectively, comparing to 15.3db and 22.7db for an inpainting based interpolation technique. SNR was 28.3, 28.3, 21.8, 19.3 and 17.3 db for gantry angle intervals of 1, 1.5, 2, 2.5 and 3 degrees, respectively. Conclusion: IPI is feasible to estimate the missing information, and achieve an reasonable CBCT image quality with reduced dose and scan time. This study is supported by NIH/NCI grant 1R01CA166948-01.

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

    Science.gov (United States)

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

    2015-01-01

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

  11. On-line use of three-dimensional marker trajectory estimation from cone-beam computed tomography projections for precise setup in radiotherapy for targets with respiratory motion.

    Science.gov (United States)

    Worm, Esben S; Høyer, Morten; Fledelius, Walther; Nielsen, Jens E; Larsen, Lars P; Poulsen, Per R

    2012-05-01

    To develop and evaluate accurate and objective on-line patient setup based on a novel semiautomatic technique in which three-dimensional marker trajectories were estimated from two-dimensional cone-beam computed tomography (CBCT) projections. Seven treatment courses of stereotactic body radiotherapy for liver tumors were delivered in 21 fractions in total to 6 patients by a linear accelerator. Each patient had two to three gold markers implanted close to the tumors. Before treatment, a CBCT scan with approximately 675 two-dimensional projections was acquired during a full gantry rotation. The marker positions were segmented in each projection. From this, the three-dimensional marker trajectories were estimated using a probability based method. The required couch shifts for patient setup were calculated from the mean marker positions along the trajectories. A motion phantom moving with known tumor trajectories was used to examine the accuracy of the method. Trajectory-based setup was retrospectively used off-line for the first five treatment courses (15 fractions) and on-line for the last two treatment courses (6 fractions). Automatic marker segmentation was compared with manual segmentation. The trajectory-based setup was compared with setup based on conventional CBCT guidance on the markers (first 15 fractions). Phantom measurements showed that trajectory-based estimation of the mean marker position was accurate within 0.3 mm. The on-line trajectory-based patient setup was performed within approximately 5 minutes. The automatic marker segmentation agreed with manual segmentation within 0.36 ± 0.50 pixels (mean ± SD; pixel size, 0.26 mm in isocenter). The accuracy of conventional volumetric CBCT guidance was compromised by motion smearing (≤21 mm) that induced an absolute three-dimensional setup error of 1.6 ± 0.9 mm (maximum, 3.2) relative to trajectory-based setup. The first on-line clinical use of trajectory estimation from CBCT projections for precise

  12. 3D algebraic iterative reconstruction for cone-beam x-ray differential phase-contrast computed tomography.

    Directory of Open Access Journals (Sweden)

    Jian Fu

    Full Text Available 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.

  13. Cone beam computed tomography in veterinary dentistry

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    National Research Council Canada - National Science Library

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

    2009-01-01

    ...) and maximum intercuspation (MI), using computed tomography volumetric cone beam (cone beam method). The sample of the study consisted of 10 asymptomatic young adult patients divided into two types of standard occlusion...

  15. SU-G-BRA-10: Marker Free Lung Tumor Motion Tracking by An Active Contour Model On Cone Beam CT Projections for Stereotactic Body Radiation Therapy of Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chao, M; Yuan, Y; Lo, Y [The Mount Sinai Medical Center, New York, NY (United States); Wei, J [City College of New York, New York, NY (United States)

    2016-06-15

    Purpose: To develop a novel strategy to extract the lung tumor motion from cone beam CT (CBCT) projections by an active contour model with interpolated respiration learned from diaphragm motion. Methods: Tumor tracking on CBCT projections was accomplished with the templates derived from planning CT (pCT). There are three major steps in the proposed algorithm: 1) The pCT was modified to form two CT sets: a tumor removed pCT and a tumor only pCT, the respective digitally reconstructed radiographs DRRtr and DRRto following the same geometry of the CBCT projections were generated correspondingly. 2) The DRRtr was rigidly registered with the CBCT projections on the frame-by-frame basis. Difference images between CBCT projections and the registered DRRtr were generated where the tumor visibility was appreciably enhanced. 3) An active contour method was applied to track the tumor motion on the tumor enhanced projections with DRRto as templates to initialize the tumor tracking while the respiratory motion was compensated for by interpolating the diaphragm motion estimated by our novel constrained linear regression approach. CBCT and pCT from five patients undergoing stereotactic body radiotherapy were included in addition to scans from a Quasar phantom programmed with known motion. Manual tumor tracking was performed on CBCT projections and was compared to the automatic tracking to evaluate the algorithm accuracy. Results: The phantom study showed that the error between the automatic tracking and the ground truth was within 0.2mm. For the patients the discrepancy between the calculation and the manual tracking was between 1.4 and 2.2 mm depending on the location and shape of the lung tumor. Similar patterns were observed in the frequency domain. Conclusion: The new algorithm demonstrated the feasibility to track the lung tumor from noisy CBCT projections, providing a potential solution to better motion management for lung radiation therapy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

  17. Markerless four-dimensional-cone beam computed tomography projection-phase sorting using prior knowledge and patient motion modeling: A feasibility study

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2017-01-01

    Conclusion: The study demonstrated the feasibility of using PCA coefficients for 4D-CBCT projection-phase sorting. High sorting accuracy in both digital phantoms and patient cases was achieved. This method provides an accurate and robust tool for automatic 4D-CBCT projection sorting using 3D motion modeling without the need of external surrogate or internal markers.

  18. A line fiducial method for geometric calibration of cone-beam CT systems with diverse scan trajectories.

    Science.gov (United States)

    Jacobson, Matthew W; Ketcha, Michael Daniel; Capostagno, Sarah; Martin, Alexander; Uneri, Ali; Goerres, Joseph; De Silva, Tharindu; Reaungamornrat, Sureerat; Han, Runze; Manbachi, Amir; Stayman, Joseph Webster; Vogt, Sebastian; Kleinszig, Gerhard; Siewerdsen, Jeffrey H

    2017-11-08

    Modern cone-beam CT systems, especially C-arms, are capable of diverse source-detector orbits. However, geometric calibration of these systems using conventional configurations of spherical fiducials (BBs) may be challenged for novel source-detector orbits and system geometries. In part, this is because the BB configurations are designed with careful forethought regarding the intended orbit so that BB marker projections do not overlap in projection views. Examples include helical arrangements of BBs (Rougee et al Proc. SPIE 1897 161-9) such that markers do not overlap in projections acquired from a circular orbit and circular arrangements of BBs (Cho et al Med Phys 32 968-83). As a more general alternative, this work proposes a calibration method based on an array of line-shaped, radio-opaque wire segments. With this method, geometric parameter estimation is accomplished by relating the 3D line equations representing the wires to the 2D line equations of their projections. The use of line fiducials simplifies many challenges with fiducial recognition and extraction in an orbit-independent manner. For example, their projections can overlap only mildly, for any gantry pose, as long as the wires are mutually non-coplanar in 3D. The method was tested in application to circular and non-circular trajectories in simulation and in real orbits executed using a mobile C-arm prototype for cone-beam CT. Results indicated high calibration accuracy, as measured by forward and backprojection/triangulation error metrics. Triangulation errors on the order of microns and backprojected ray deviations uniformly less than 0.2 mm were observed in both real and simulated orbits. Mean forward projection errors less than 0.1 mm were observed in a comprehensive sweep of different C-arm gantry angulations. Finally, successful integration of the method into a CT imaging chain was demonstrated in head phantom scans. © 2017 Institute of Physics and Engineering in Medicine.

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

    DEFF Research Database (Denmark)

    Christoffersen, Christian; Hansen, David Christoffer; Poulsen, Per Rugaard

    2013-01-01

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

  20. Scatter corrections for cone beam optical CT

    Energy Technology Data Exchange (ETDEWEB)

    Olding, Tim; Holmes, Oliver [Department of Physics, Queen' s University (United Kingdom); Schreiner, L John [Medical Physics Department, Cancer Centre of Southeastern Ontario (Canada)], E-mail: Tim.Olding@krcc.on.ca

    2009-05-01

    Cone beam optical computed tomography (OptCT) employing the VISTA scanner (Modus Medical, London, ON) has been shown to have significant promise for fast, three dimensional imaging of polymer gel dosimeters. One distinct challenge with this approach arises from the combination of the cone beam geometry, a diffuse light source, and the scattering polymer gel media, which all contribute scatter signal that perturbs the accuracy of the scanner. Beam stop array (BSA), beam pass array (BPA) and anti-scatter polarizer correction methodologies have been employed to remove scatter signal from OptCT data. These approaches are investigated through the use of well-characterized phantom scattering solutions and irradiated polymer gel dosimeters. BSA corrected scatter solutions show good agreement in attenuation coefficient with the optically absorbing dye solutions, with considerable reduction of scatter-induced cupping artifact at high scattering concentrations. The application of BSA scatter corrections to a polymer gel dosimeter lead to an overall improvement in the number of pixel satisfying the (3%, 3mm) gamma value criteria from 7.8% to 0.15%.

  1. Comparing cone beam laminographic system trajectories for composite NDT

    Directory of Open Access Journals (Sweden)

    Neil O'Brien

    2016-11-01

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

  2. Exact Interior Reconstruction with Cone-Beam CT

    Directory of Open Access Journals (Sweden)

    Yangbo Ye

    2007-01-01

    Full Text Available Using the backprojection filtration (BPF and filtered backprojection (FBP approaches, respectively, we prove that with cone-beam CT the interior problem can be exactly solved by analytic continuation. The prior knowledge we assume is that a volume of interest (VOI in an object to be reconstructed is known in a subregion of the VOI. Our derivations are based on the so-called generalized PI-segment (chord. The available projection onto convex set (POCS algorithm and singular value decomposition (SVD method can be applied to perform the exact interior reconstruction. These results have many implications in the CT field and can be extended to other tomographic modalities, such as SPECT/PET, MRI.

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

    Directory of Open Access Journals (Sweden)

    Sreenivas Rao Ghali

    2017-01-01

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

  4. Cone beam computed tomography in endodontic

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  5. Numerical Aspects of Cone Beam Contour Reconstruction

    Science.gov (United States)

    Louis, Alfred K.

    2017-12-01

    We describe a method for directly calculating the contours of a function from cone beam data. The algorithm is based on a new inversion formula for the gradient of a function presented in Louis (Inverse Probl 32(11):115005, 2016. http://stacks.iop.org/0266-5611/32/i=11/a=115005). The Radon transform of the gradient is found by using a Grangeat type of formula, reducing the inversion problem to the inversion of the Radon transform. In that way the influence of the scanning curve, vital for all exact inversion formulas for complete data, is avoided Numerical results are presented for the circular scanning geometry which neither fulfills the Tuy-Kirillov condition nor the much weaker condition given by the author in Louis (Inverse Probl 32(11):115005, 2016. http://stacks.iop.org/0266-5611/32/i=11/a=115005).

  6. 3D dictionary learning based iterative cone beam CT reconstruction

    Directory of Open Access Journals (Sweden)

    Ti Bai

    2014-03-01

    Full Text Available Purpose: This work is to develop a 3D dictionary learning based cone beam CT (CBCT reconstruction algorithm on graphic processing units (GPU to improve the quality of sparse-view CBCT reconstruction with high efficiency. Methods: A 3D dictionary containing 256 small volumes (atoms of 3 × 3 × 3 was trained from a large number of blocks extracted from a high quality volume image. On the basis, we utilized cholesky decomposition based orthogonal matching pursuit algorithm to find the sparse representation of each block. To accelerate the time-consuming sparse coding in the 3D case, we implemented the sparse coding in a parallel fashion by taking advantage of the tremendous computational power of GPU. Conjugate gradient least square algorithm was adopted to minimize the data fidelity term. Evaluations are performed based on a head-neck patient case. FDK reconstruction with full dataset of 364 projections is used as the reference. We compared the proposed 3D dictionary learning based method with tight frame (TF by performing reconstructions on a subset data of 121 projections. Results: Compared to TF based CBCT reconstruction that shows good overall performance, our experiments indicated that 3D dictionary learning based CBCT reconstruction is able to recover finer structures, remove more streaking artifacts and also induce less blocky artifacts. Conclusion: 3D dictionary learning based CBCT reconstruction algorithm is able to sense the structural information while suppress the noise, and hence to achieve high quality reconstruction under the case of sparse view. The GPU realization of the whole algorithm offers a significant efficiency enhancement, making this algorithm more feasible for potential clinical application.-------------------------------Cite this article as: Bai T, Yan H, Shi F, Jia X, Lou Y, Xu Q, Jiang S, Mou X. 3D dictionary learning based iterative cone beam CT reconstruction. Int J Cancer Ther Oncol 2014; 2(2:020240. DOI: 10

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

    Science.gov (United States)

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

    2004-05-01

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

  8. Cone beam computed tomography in veterinary dentistry.

    Science.gov (United States)

    Van Thielen, Bert; Siguenza, Francis; Hassan, Bassam

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal reconstructions were created using specialized software. Image quality and visibility of anatomical landmarks were subjectively assessed by two observers. Good image quality was obtained for the MPR para-sagittal reconstructions through multiple teeth. The image quality of the panoramic reconstructions of dogs was moderate while the panoramic reconstructions of cats were poor since the images were associated with an increased noise level. Segmental panoramic reconstructions of the mouth seem to be useful for studying the dental anatomy especially in dogs. The results of this study using human dental CBCT technology demonstrate the potential of this scanning technology in veterinary medicine. Unfortunately, the moderate image quality obtained with the CBCT technique reported here seems to be inferior to the diagnostic image quality obtained from 2-dimensional dental radiographs. Further research is required to optimize scanning and reconstruction protocols for veterinary applications.

  9. Cone Beam Computed Tomographic imaging in orthodontics.

    Science.gov (United States)

    Scarfe, W C; Azevedo, B; Toghyani, S; Farman, A G

    2017-03-01

    Over the last 15 years, cone beam computed tomographic (CBCT) imaging has emerged as an important supplemental radiographic technique for orthodontic diagnosis and treatment planning, especially in situations which require an understanding of the complex anatomic relationships and surrounding structures of the maxillofacial skeleton. CBCT imaging provides unique features and advantages to enhance orthodontic practice over conventional extraoral radiographic imaging. While it is the responsibility of each practitioner to make a decision, in tandem with the patient/family, consensus-derived, evidence-based clinical guidelines are available to assist the clinician in the decision-making process. Specific recommendations provide selection guidance based on variables such as phase of treatment, clinically-assessed treatment difficulty, the presence of dental and/or skeletal modifying conditions, and pathology. CBCT imaging in orthodontics should always be considered wisely as children have conservatively, on average, a three to five times greater radiation risk compared with adults for the same exposure. The purpose of this paper is to provide an understanding of the operation of CBCT equipment as it relates to image quality and dose, highlight the benefits of the technique in orthodontic practice, and provide guidance on appropriate clinical use with respect to radiation dose and relative risk, particularly for the paediatric patient. © 2017 Australian Dental Association.

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

    OpenAIRE

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

    2009-01-01

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

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

    OpenAIRE

    FERREIRA, Amanda de Freitas; HENRIQUES, Jo?o C?sar Guimar?es; Almeida, Guilherme de Ara?jo; Machado, Asbel Rodrigues; Machado, Naila Aparecida de Godoi; Fernandes, Alfredo J?lio

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2009-01-01

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

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

    Science.gov (United States)

    Sramek, Benjamin Koerner

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

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

    Directory of Open Access Journals (Sweden)

    Mahnaz Sheikhi

    2015-01-01

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

  15. SU-F-J-205: Effect of Cone Beam Factor On Cone Beam CT Number Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Yao, W; Hua, C; Farr, J; Brady, S; Merchant, T [St. Jude Children’s Research Hospital, Memphis, TN (United States)

    2016-06-15

    Purpose: To examine the suitability of a Catphan™ 700 phantom for image quality QA of a cone beam computed tomography (CBCT) system deployed for proton therapy. Methods: Catphan phantoms, particularly Catphan™ 504, are commonly used in image quality QA for CBCT. As a newer product, Catphan™ 700 offers more tissue equivalent inserts which may be useful for generating the electron density – CT number curve for CBCT based treatment planning. The sensitometry-and-geometry module used in Catphan™ 700 is located at the end of the phantom and after the resolution line pair module. In Catphan™ 504 the line pair module is located at the end of the phantom and after the sensitometry-and-geometry module. To investigate the effect of difference in location on CT number accuracy due to the cone beam factor, we scanned the Catphan™ 700 with the central plane of CBCT at the center of the phantom, line pair and sensitometry-andgeometry modules of the phantom, respectively. The protocol head and thorax scan modes were used. For each position, scans were repeated 4 times. Results: For the head scan mode, the standard deviation (SD) of the CT numbers of each insert under 4 repeated scans was up to 20 HU, 11 HU, and 11 HU, respectively, for the central plane of CBCT located at the center of the phantom, line pair, and sensitometry-and-geometry modules of the phantom. The mean of the SD was 9.9 HU, 5.7 HU, and 5.9 HU, respectively. For the thorax mode, the mean of the SD was 4.5 HU, 4.4 HU, and 4.4 HU, respectively. The assessment of image quality based on resolution and spatial linearity was not affected by imaging location changes. Conclusion: When the Catphan™ 700 was aligned to the center of imaging region, the CT number accuracy test may not meet expectations. We recommend reconfiguration of the modules.

  16. Use of cone beam computed tomography in periodontology

    Science.gov (United States)

    Acar, Buket; Kamburoğlu, Kıvanç

    2014-01-01

    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. PMID:24876918

  17. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul [Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh); Kim, Jae Gon; Lee, Soo Yeol, E-mail: khasan@eee.buet.ac.b [Department of Biomedical Engineering, Kyung Hee University, Kyungki 446-701 (Korea, Republic of)

    2011-10-07

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-21

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

  19. A new method for x-ray scatter correction: first assessment on a cone-beam CT experimental setup

    Energy Technology Data Exchange (ETDEWEB)

    Rinkel, J [CEA-LETI MINATEC, Division of Micro Technologies for Biology and Healthcare, 38054 Grenoble Cedex 09 (France); Gerfault, L [CEA-LETI MINATEC, Division of Micro Technologies for Biology and Healthcare, 38054 Grenoble Cedex 09 (France); Esteve, F [INSERM U647-RSRM, ESRF, BP200, 38043 Grenoble Cedex 09 (France); Dinten, J-M [CEA-LETI MINATEC, Division of Micro Technologies for Biology and Healthcare, 38054 Grenoble Cedex 09 (France)

    2007-08-07

    Cone-beam computed tomography (CBCT) enables three-dimensional imaging with isotropic resolution and a shorter acquisition time compared to a helical CT scanner. Because a larger object volume is exposed for each projection, scatter levels are much higher than in collimated fan-beam systems, resulting in cupping artifacts, streaks and quantification inaccuracies. In this paper, a general method to correct for scatter in CBCT, without supplementary on-line acquisition, is presented. This method is based on scatter calibration through off-line acquisition combined with on-line analytical transformation based on physical equations, to adapt calibration to the object observed. The method was tested on a PMMA phantom and on an anthropomorphic thorax phantom. The results were validated by comparison to simulation for the PMMA phantom and by comparison to scans obtained on a commercial multi-slice CT scanner for the thorax phantom. Finally, the improvements achieved with the new method were compared to those obtained using a standard beam-stop method. The new method provided results that closely agreed with the simulation and with the conventional CT scanner, eliminating cupping artifacts and significantly improving quantification. Compared to the beam-stop method, lower x-ray doses and shorter acquisition times were needed, both divided by a factor of 9 for the same scatter estimation accuracy.

  20. Helical Screw Expander Evaluation Project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McKay, R.

    1982-03-01

    A functional 1-MW geothermal electric power plant that featured a helical screw expander was produced and then tested in Utah in 1978 to 1979 with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing operation on two-phase geothermal fluids. The Project also produced a computer-equipped data system, an instrumentation and control van, and a 1000-kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Additional testing was performed in Mexico in 1980 under a cooperative test program using the same test array, and machine efficiency was measured at 62% maximum with the rotors partially coated with scale, compared with approximately 54% maximum in Utah with uncoated rotors, confirming the importance of scale deposits within the machine on performance. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  1. Cone beam computed tomography in Endodontics - a review

    NARCIS (Netherlands)

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

    2015-01-01

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

  2. Actively triggered 4d cone-beam CT acquisition

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-15

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

  3. Dentomaxillofacial imaging with panoramic views and cone beam CT.

    Science.gov (United States)

    Suomalainen, Anni; Pakbaznejad Esmaeili, Elmira; Robinson, Soraya

    2015-02-01

    Panoramic and intraoral radiographs are the basic imaging modalities used in dentistry. Often they are the only imaging techniques required for delineation of dental anatomy or pathology. Panoramic radiography produces a single image of the maxilla, mandible, teeth, temporomandibular joints and maxillary sinuses. During the exposure the x-ray source and detector rotate synchronously around the patient producing a curved surface tomography. It can be supplemented with intraoral radiographs. However, these techniques give only a two-dimensional view of complicated three-dimensional (3D) structures. As in the other fields of imaging also dentomaxillofacial imaging has moved towards 3D imaging. Since the late 1990s cone beam computed tomography (CBCT) devices have been designed specifically for dentomaxillofacial imaging, allowing accurate 3D imaging of hard tissues with a lower radiation dose, lower cost and easier availability for dentists when compared with multislice CT. Panoramic and intraoral radiographies are still the basic imaging methods in dentistry. CBCT should be used in more demanding cases. In this review the anatomy with the panoramic view will be presented as well as the benefits of the CBCT technique in comparison to the panoramic technique with some examples. Also the basics as well as common errors and pitfalls of these techniques will be discussed. Teaching Points • Panoramic and intraoral radiographs are the basic imaging methods in dentomaxillofacial radiology.• CBCT imaging allows accurate 3D imaging of hard tissues.• CBCT offers lower costs and a smaller size and radiation dose compared with MSCT.• The disadvantages of CBCT imaging are poor soft tissue contrast and artefacts.• The Sedentexct project has developed evidence-based guidelines on the use of CBCT in dentistry.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-15

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

  5. Region-of-interest reconstruction for a cone-beam dental CT with a circular trajectory

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Zhanli, E-mail: huzhanli1983@gmail.com [Paul C. Lauterbur Research Center For Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Zou, Jing; Gui, Jianbao; Zheng, Hairong [Paul C. Lauterbur Research Center For Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Xia, Dan, E-mail: dan.xia@siat.ac.cn [Paul C. Lauterbur Research Center For Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)

    2013-04-21

    Dental CT is the most appropriate and accurate device for preoperative evaluation of dental implantation. It can demonstrate the quantity of bone in three dimensions (3D), the location of important adjacent anatomic structures and the quality of available bone with minimal geometric distortion. Nevertheless, with the rapid increase of dental CT examinations, we are facing the problem of dose reduction without loss of image quality. In this work, backprojection-filtration (BPF) and Feldkamp–Davis–Kress (FDK) algorithm was applied to reconstruct the 3D full image and region-of-interest (ROI) image from complete and truncated circular cone-beam data respectively by computer-simulation. In addition, the BPF algorithm was evaluated based on the 3D ROI-image reconstruction from real data, which was acquired from our developed circular cone-beam prototype dental CT system. The results demonstrated that the ROI-image quality reconstructed from truncated data using the BPF algorithm was comparable to that reconstructed from complete data. The FDK algorithm, however, created artifacts while reconstructing ROI-image. Thus it can be seen, for circular cone-beam dental CT, reducing scanning angular range of the BPF algorithm used for ROI-image reconstruction are helpful for reducing the radiation dose and scanning time. Finally, an analytical method was developed for estimation of the ROI projection area on the detector before CT scanning, which would help doctors to roughly estimate the total radiation dose before the CT examination. -- Highlights: ► BPF algorithm was applied by using dental CT for the first time. ► A method was developed for estimation of projection region before CT scanning. ► Roughly predict the total radiation dose before CT scans. ► Potential reduce imaging radiation dose, scatter, and scanning time.

  6. GPU-accelerated regularized iterative reconstruction for few-view cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-15

    Purpose: The present work proposes an iterative reconstruction technique designed for x-ray transmission computed tomography (CT). The main objective is to provide a model-based solution to the cone-beam CT reconstruction problem, yielding accurate low-dose images via few-views acquisitions in clinically acceptable time frames. Methods: The proposed technique combines a modified ordered subsets convex (OSC) algorithm and the total variation minimization (TV) regularization technique and is called OSC-TV. The number of subsets of each OSC iteration follows a reduction pattern in order to ensure the best performance of the regularization method. Considering the high computational cost of the algorithm, it is implemented on a graphics processing unit, using parallelization to accelerate computations. Results: The reconstructions were performed on computer-simulated as well as human pelvic cone-beam CT projection data and image quality was assessed. In terms of convergence and image quality, OSC-TV performs well in reconstruction of low-dose cone-beam CT data obtained via a few-view acquisition protocol. It compares favorably to the few-view TV-regularized projections onto convex sets (POCS-TV) algorithm. It also appears to be a viable alternative to full-dataset filtered backprojection. Execution times are of 1–2 min and are compatible with the typical clinical workflow for nonreal-time applications. Conclusions: Considering the image quality and execution times, this method may be useful for reconstruction of low-dose clinical acquisitions. It may be of particular benefit to patients who undergo multiple acquisitions by reducing the overall imaging radiation dose and associated risks.

  7. Shading correction assisted iterative cone-beam CT reconstruction

    Science.gov (United States)

    Yang, Chunlin; Wu, Pengwei; Gong, Shutao; Wang, Jing; Lyu, Qihui; Tang, Xiangyang; Niu, Tianye

    2017-11-01

    Recent advances in total variation (TV) technology enable accurate CT image reconstruction from highly under-sampled and noisy projection data. The standard iterative reconstruction algorithms, which work well in conventional CT imaging, fail to perform as expected in cone beam CT (CBCT) applications, wherein the non-ideal physics issues, including scatter and beam hardening, are more severe. These physics issues result in large areas of shading artifacts and cause deterioration to the piecewise constant property assumed in reconstructed images. To overcome this obstacle, we incorporate a shading correction scheme into low-dose CBCT reconstruction and propose a clinically acceptable and stable three-dimensional iterative reconstruction method that is referred to as the shading correction assisted iterative reconstruction. In the proposed method, we modify the TV regularization term by adding a shading compensation image to the reconstructed image to compensate for the shading artifacts while leaving the data fidelity term intact. This compensation image is generated empirically, using image segmentation and low-pass filtering, and updated in the iterative process whenever necessary. When the compensation image is determined, the objective function is minimized using the fast iterative shrinkage-thresholding algorithm accelerated on a graphic processing unit. The proposed method is evaluated using CBCT projection data of the Catphan© 600 phantom and two pelvis patients. Compared with the iterative reconstruction without shading correction, the proposed method reduces the overall CT number error from around 200 HU to be around 25 HU and increases the spatial uniformity by a factor of 20 percent, given the same number of sparsely sampled projections. A clinically acceptable and stable iterative reconstruction algorithm for CBCT is proposed in this paper. Differing from the existing algorithms, this algorithm incorporates a shading correction scheme into the low

  8. Mandibular condyle position in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-06-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-15

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

  10. Endodontic practice management with cone-beam computed tomography

    OpenAIRE

    Priyank Sethi; Ritu Tiwari; Maneesha Das; Mahesh Pratap Singh; Manish Agarwal; Alfred Joseph Ravikumar

    2017-01-01

    Traditionally, conventional periapical radiology formed the backbone of endodontics for diagnosis, treatment planning, and management. One of the major associated gripes being the technique created two-dimensional images of three-dimensional (3D) structures, suffered magnification, superimposition, and distortion, leading to compromised diagnostic information. The need to analyze the area of interest in all the possible planes led to the introduction of cone-beam computed tomography (CBCT), a...

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

    Science.gov (United States)

    Makdissi, Jimmy

    2013-03-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  13. Use of Cone Beam Computed Tomography in Endodontics

    Science.gov (United States)

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-15

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

  15. Scatter correction for cone-beam CT in radiation therapy.

    Science.gov (United States)

    Zhu, Lei; Xie, Yaoqin; Wang, Jing; Xing, Lei

    2009-06-01

    Cone-beam CT (CBCT) is being increasingly used in modern radiation therapy for patient setup and adaptive replanning. However, due to the large volume of x-ray illumination, scatter becomes a rather serious problem and is considered as one of the fundamental limitations of CBCT image quality. Many scatter correction algorithms have been proposed in literature, while a standard practical solution still remains elusive. In radiation therapy, the same patient is scanned repetitively during a course of treatment, a natural question to ask is whether one can obtain the scatter distribution on the first day of treatment and then use the data for scatter correction in the subsequent scans on different days. To realize this scatter removal scheme, two technical pieces must be in place: (i) A strategy to obtain the scatter distribution in on-board CBCT imaging and (ii) a method to spatially match a prior scatter distribution with the on-treatment CBCT projection data for scatter subtraction. In this work, simple solutions to the two problems are provided. A partially blocked CBCT is used to extract the scatter distribution. The x-ray beam blocker has a strip pattern, such that partial volume can still be accurately reconstructed and the whole-field scatter distribution can be estimated from the detected signals in the shadow regions using interpolation/extrapolation. In the subsequent scans, the patient transformation is determined using a rigid registration of the conventional CBCT and the prior partial CBCT. From the derived patient transformation, the measured scatter is then modified to adapt the new on-treatment patient geometry for scatter correction. The proposed method is evaluated using physical experiments on a clinical CBCT system. On the Catphan 600 phantom, the errors in Hounsfield unit (HU) in the selected regions of interest are reduced from about 350 to below 50 HU; on an anthropomorphic phantom, the error is reduced from 15.7% to 5.4%. The proposed method

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

    Directory of Open Access Journals (Sweden)

    Amanda de Freitas Ferreira

    2009-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  18. Megavoltage cone-beam CT: recent developments and clinical applications; Megavoltage cone-beam CT: recents developpements et applications cliniques pour la radiotherapie conformationnelle avec modulation d'intensite

    Energy Technology Data Exchange (ETDEWEB)

    Pouliot, J.; Morin, O.; Aubin, M.; Aubry, J.F.; Chen, J.; Speight, J.; Roach, M. [California San Francisco Univ., Deptq. of radiation oncology, comprehensive cancer center, San Francisco, Ca (United States)

    2006-09-15

    The Megavoltage cone-beam (MV CBCT) system consists of a new a-Si flat panel adapted for MV imaging and an integrated work-flow application allowing the automatic acquisition of projection images, cone-beam CT image reconstruction, CT to CBCT image registration and couch position adjustment. This provides a 3D patient anatomy volume in the actual treatment position, relative to the treatment isocenter, moments before the dose delivery, that can be tightly aligned to the planning CT, allowing verification and correction of the patient position, detection of anatomical changes and dose calculation. In this paper, we present the main advantages and performance of this MV CBCT system and summarize the different clinical applications. Examples of the image-guided treatment process from the acquisition of the MV CBCT scan to the correction of the couch position and dose delivery will be presented for spinal and lung lesions and for head and neck, and prostate cancers. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Lohse, Christian

    2015-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Suhas P Pande

    2015-01-01

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

  2. An optimization-based method for geometrical calibration in cone-beam CT without dedicated phantoms.

    Science.gov (United States)

    Panetta, D; Belcari, N; Del Guerra, A; Moehrs, S

    2008-07-21

    In this paper we present a new method for the determination of geometrical misalignments in cone-beam CT scanners, from the analysis of the projection data of a generic object. No a priori knowledge of the object shape and positioning is required. We show that a cost function, which depends on the misalignment parameters, can be defined using the projection data and that such a cost function has a local minimum in correspondence to the actual parameters of the system. Hence, the calibration of the scanner can be carried out by minimizing the cost function using standard optimization techniques. The method is developed for a particular class of 3D object functions, for which the redundancy of the fan beam sinogram in the transaxial midplane can be extended to cone-beam projection data, even at wide cone angles. The method has an approximated validity for objects which do not belong to that class; in that case, a suitable subset of the projection data can be selected in order to compute the cost function. We show by numerical simulations that our method is capable to determine with high accuracy the most critical misalignment parameters of the scanner, i.e., the transversal shift and the skew of the detector. Additionally, the detector slant can be determined. Other parameters such as the detector tilt, the longitudinal shift and the error in the source-detector distance cannot be determined with our method, as the proposed cost function has a very weak dependence on them. However, due to the negligible influence of these latter parameters in the reconstructed image quality, they can be kept fixed at estimated values in both calibration and reconstruction processes without compromising the final result. A trade-off between computational cost and calibration accuracy must be considered when choosing the data subset used for the computation of the cost function. Results on real data of a mouse femur as obtained with a small animal micro-CT are shown as well, proving

  3. An optimization-based method for geometrical calibration in cone-beam CT without dedicated phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Panetta, D; Belcari, N; Guerra, A Del; Moehrs, S [Department of Physics ' E. Fermi' , University of Pisa, L.go B. Pontecorvo, 3-I-56127 Pisa (Italy)], E-mail: daniele.panetta@pi.infn.it

    2008-07-21

    In this paper we present a new method for the determination of geometrical misalignments in cone-beam CT scanners, from the analysis of the projection data of a generic object. No a priori knowledge of the object shape and positioning is required. We show that a cost function, which depends on the misalignment parameters, can be defined using the projection data and that such a cost function has a local minimum in correspondence to the actual parameters of the system. Hence, the calibration of the scanner can be carried out by minimizing the cost function using standard optimization techniques. The method is developed for a particular class of 3D object functions, for which the redundancy of the fan beam sinogram in the transaxial midplane can be extended to cone-beam projection data, even at wide cone angles. The method has an approximated validity for objects which do not belong to that class; in that case, a suitable subset of the projection data can be selected in order to compute the cost function. We show by numerical simulations that our method is capable to determine with high accuracy the most critical misalignment parameters of the scanner, i.e., the transversal shift and the skew of the detector. Additionally, the detector slant can be determined. Other parameters such as the detector tilt, the longitudinal shift and the error in the source-detector distance cannot be determined with our method, as the proposed cost function has a very weak dependence on them. However, due to the negligible influence of these latter parameters in the reconstructed image quality, they can be kept fixed at estimated values in both calibration and reconstruction processes without compromising the final result. A trade-off between computational cost and calibration accuracy must be considered when choosing the data subset used for the computation of the cost function. Results on real data of a mouse femur as obtained with a small animal micro-CT are shown as well, proving

  4. Analysis of the mental foramen using cone beam computerized tomography

    Directory of Open Access Journals (Sweden)

    Kunihiro Saito

    Full Text Available AbstractIntroductionKnowledge of the anatomical structures located in the region between the mental foramina is of critical importance in pre-operative planning.ObjectiveTo evaluate the position of the mental foramen relative to the apices of the teeth and the distance to the edges of the mandible, using cone beam computerized tomography.Material and methodOne hundred cone beam computerized tomographs of the mandible were evaluated; the tomographs were taken using a single tomographic device. Each image chosen was evaluated repeatedly from both sides of the mandible, the position of the mental foramen, indicating the region in which the foramen was found and the measures of the mental foramen, the lingual cortex and the mandibular base. Initially, the data were analyzed descriptively. A value of pResultForty-two percent of the mental foramina were located in the apex of the second pre-molar. The lingual margin of the mental foramen was located, on average, 3.1mm from the lingual cortex. The lower margin of the mental foramen was located 7.25 mm above the lower edge of the mandible.ConclusionThe mental foramen was located more frequently at a level of the apices of the second pre-molars, with a distance to the lingual cortex, on average, of 3.1mm and to the base of the mandible, on average, of 7.25 mm.

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

    CERN Document Server

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

    2016-01-01

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

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

    Science.gov (United States)

    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.

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

    CERN Document Server

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

    2015-01-01

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

  8. Assessment of zygomatic bone using cone beam computed tomography in a Turkish population.

    Science.gov (United States)

    Kamburoğlu, Kıvanç; Kirşan Büyükkoçak, Burcu; Acar, Buket; Paksoy, Candan Semra

    2017-02-01

    To provide linear and volumetric measurements of zygomatic bone using cone beam computed tomography (CBCT) images. CBCT images were assessed for 198 patients. Posterior and anterior zygomatic bone widths (M1 and M2), zygomatic bone projection (M3), zygomatic bone height (M4), combined zygomatic arch diameter (M5), maximum cortical thickness (M6), gray value obtained from maximum cortical thickness region (M7), minimum cortical thickness (M8), and gray value obtained from minimum cortical thickness region (M9) were measured. Volume and surface area measurements of the zygomatic bone were also conducted. Sex, age, and side were recorded for each patient. General linear model analysis of variance (ANOVA) was performed (P zygomatic bone volume variation (gender, P = .000; age, P = .000; and side, P zygomatic bone region can be performed with CBCT images. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Cone Beam Computed Tomography Evaluation of Inverted Mesiodentes.

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    AlJehani, Yousef A.

    2014-01-01

    Objectives. This paper aims to review the diagnostic application of cone beam computed tomography (CBCT) in the field of periodontology. Data. Original articles that reported on the use of CBCT for periodontal disease diagnosis were included. Sources. MEDLINE (1990 to January 2014), PubMed (using medical subject headings), and Google Scholar were searched using the following terms in different combinations: “CBCT,” “volumetric CT,” “periodontal disease ,” and “periodontitis.” This was supplemented by hand-searching in peer-reviewed journals and cross-referenced with the articles accessed. Conclusions. Bony defects, caters, and furcation involvements seem to be better depicted on CBCT, whereas bone quality and periodontal ligament space scored better on conventional intraoral radiography. CBCT does not offer a significant advantage over conventional radiography for assessing the periodontal bone levels. PMID:24803932

  11. Using cone beam computed tomography images to diagnose multiple taurodontisms.

    Science.gov (United States)

    Borges, Alvaro Henrique; Mamede-Neto, Iussif; Volpato, Luiz Evaristo Ricci; Pedro, Fabio Luis Miranda; Bueno, Mike Reis; Estrela, Carlos

    2014-01-01

    Taurodontism is a developmental anomaly that manifests as an alteration in a patient's internal morphology and is characterized by the lack of constriction at the level of the cementoenamel junction, which results in an apical extension of the pulp chamber that extends into the root area of a multiradicular tooth. This report presents a case of an otherwise healthy patient with 12 hypertaurodontic teeth, which were detected by using cone beam computed tomography (CBCT). It is essential to emphasize the importance of routine imaging examinations for diagnosing developmental dental anomalies such as taurodontism, as this condition is generally not found by routine oral examination, and is not necessarily restricted to syndromic patients. CBCT images contribute to the diagnosis of and treatment plan for taurodontism.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-15

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

  13. Endodontic practice management with cone-beam computed tomography

    Directory of Open Access Journals (Sweden)

    Priyank Sethi

    2017-01-01

    Full Text Available Traditionally, conventional periapical radiology formed the backbone of endodontics for diagnosis, treatment planning, and management. One of the major associated gripes being the technique created two-dimensional images of three-dimensional (3D structures, suffered magnification, superimposition, and distortion, leading to compromised diagnostic information. The need to analyze the area of interest in all the possible planes led to the introduction of cone-beam computed tomography (CBCT, a novel modality specifically designed to produce precise, undistorted 3D reconstructed images of the maxillofacial skeleton. CBCT is increasingly being embraced by various fields in dentistry, remarkably in endodontic practice. A systematic literature-based and book-based review was conducted using the keywords “CBCT in endodontics” and “endodontic applications of CBCT.” This article hereby discusses the prospects of CBCT in endodontics with an emphasis on its application in diagnosis and management along with treatment outcome assessment.

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

    Directory of Open Access Journals (Sweden)

    Yousef A. AlJehani

    2014-01-01

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

  15. Adaptive radiotherapy based on contrast enhanced cone beam CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Soevik, Aaste; Skogmo, Hege K. (Dept. of Companion Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo (Norway)), E-mail: aste.sovik@nvh.no; Roedal, Jan (Dept. of Companion Animal Clinical Sciences, Norwegian School of Veterinary Science, Oslo (Norway)); Lervaag, Christoffer; Eilertsen, Karsten; Malinen, Eirik (Dept. of Medical Physics, The Norwegian Radium Hospital, Oslo Univ. Hospital, Oslo (Norway))

    2010-10-15

    Cone beam CT (CBCT) imaging has become an integral part of radiation therapy, with images typically used for offline or online patient setup corrections based on bony anatomy co-registration. Ideally, the co-registration should be based on tumor localization. However, soft tissue contrast in CBCT images may be limited. In the present work, contrast enhanced CBCT (CECBCT) images were used for tumor visualization and treatment adaptation. Material and methods. A spontaneous canine maxillary tumor was subjected to repeated cone beam CT imaging during fractionated radiotherapy (10 fractions in total). At five of the treatment fractions, CECBCT images, employing an iodinated contrast agent, were acquired, as well as pre-contrast CBCT images. The tumor was clearly visible in post-contrast minus pre-contrast subtraction images, and these contrast images were used to delineate gross tumor volumes. IMRT dose plans were subsequently generated. Four different strategies were explored: 1) fully adapted planning based on each CECBCT image series, 2) planning based on images acquired at the first treatment fraction and patient repositioning following bony anatomy co-registration, 3) as for 2), but with patient repositioning based on co-registering contrast images, and 4) a strategy with no patient repositioning or treatment adaptation. The equivalent uniform dose (EUD) and tumor control probability (TCP) calculations to estimate treatment outcome for each strategy. Results. Similar translation vectors were found when bony anatomy and contrast enhancement co-registration were compared. Strategy 1 gave EUDs closest to the prescription dose and the highest TCP. Strategies 2 and 3 gave EUDs and TCPs close to that of strategy 1, with strategy 3 being slightly better than strategy 2. Even greater benefits from strategies 1 and 3 are expected with increasing tumor movement or deformation during treatment. The non-adaptive strategy 4 was clearly inferior to all three adaptive strategies

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

    Science.gov (United States)

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

    2012-03-01

    Volumetric computed cone beam tomography offers a number of significant advantages over conventional intraoral and extraoral panoramic radiography, as well as computed tomography. To date, periodontal diagnosis has relied heavily on the assessment of both intraoral radiographs and extraoral panoramic radiographs. With emerging technology in radiology there has been considerable interest in the role that volumetric cone beam computed tomography might play in periodontal diagnostics. This narrative reviews the current evidence and considers whether there is a role for volumetric cone beam computed tomography in periodontics. © 2012 Australian Dental Association.

  17. Volumetric accuracy of cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    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 [Dept. of Oral and Maxillofacial Radiology, Graduate School, Kyung Hee University, Seoul (Korea, Republic of)

    2017-09-15

    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.

  18. Cone beam computed tomography findings of impacted upper canines

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-15

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

  20. Volumetric accuracy of cone-beam computed tomography.

    Science.gov (United States)

    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.

  1. Radiographic evaluation of dentigerous cyst with cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Chan; Lee, Wan; Lee, Byung Do [School of Dentisity, Wonkwang University, Iksan (Korea, Republic of)

    2010-09-15

    The purpose of this study was to accurately analyze the radiographic characteristics of dentigerous cyst (DC) with multiplanar images of cone beam computed tomography (CBCT). Thirty eight radiographically and histopathologically proven cases of DCs were analyzed with panoramic radiograph and CBCT, retrospectively. The radiographic CT pattern, symmetry of radiolucency around the unerupted tooth crown, ratio of long length to short length, degree of cortical bone alternation, effects on adjacent tooth, and cyst size were analyzed. Relative frequencies of these radiographic features were evaluated. In order to compare the CBCT features of DC with those of odontogenic keratocyst (OKC), 9 cases of OKCs were analyzed with the same method radiographically. DCs consisted of thirty unilocular cases (79.0%), seven lobulated cases (18.4%) and one multilocular case (2.6%). Eight were asymmetric (21.0%) and thirty were symmetric (79.0%). Maxillary DC showed rounder shape than mandibular DC (L/S ratio; maxilla 1.32, mandible 1.67). Alternations of lingual cortical bone (14 cases, 48.2%) were more frequent than those of buccal side (7 cases, 24.1%). CBCT images of DC showed definite root resorption and bucco-lingual tooth displacement. These findings were hardly observed on panoramic radiographs of DCs. Comparison of CBCT features of DC with those of OKC showed several different features. CBCT images of DC showed various characteristic radiographic features. Therefore, CBCT can be helpful for the diagnosis of DC radiographically.

  2. EVALUATION OF KERATOCYSTIC ODONTOGENIC TUMORS USING CONE BEAM COMPUTED TOMOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mustafa Gümüşok

    2016-10-01

    Full Text Available Purpose: The aim of this retrospective study is to determine the radiological features of keratocystic odontogenic tumors (KCOT using cone-beam computed tomography (CBCT.Materials and Methods: CBCT images of 28 patients who had histopathologically-confirmed KCOT were retrospectively reviewed from the archives of the Department of Dentomaxillofacial Radiology, Gazi University Faculty of Dentistry. The location and size of KCOT, cortical expansion, cortical perforation, relation with the impacted teeth, and the impact on the mandibular canal were evaluated. Results: The mean age of patients at initial diagnosis was 34.5 years. Patients with an impacted tooth were significantly younger than those without an impacted tooth (p<0.05. Among KCOTs, 21% were localized in the maxilla whereas 79% were found in the mandible. The lesions localized in the mandible were mostly found in the retromolar-ramus region. Of these patients, 93% had cortical expansion and 75% had bone perforation. Of the 22 mandibular lesions, 20 were in close proximity of the mandibular canal and 18 (90% of these lesions had caused destruction in the mandibular canal. Conclusion: KCOTs exhibit their aggressive nature in the jaw bone. CBCT is a useful radiological imaging method to examine the radiologic characteristics of KCOTs such as bone destruction and their spatial relations with the neighboring anatomic structures.

  3. Evaluation of inter-observer variability of bladder boundary delineation on cone-beam CT

    National Research Council Canada - National Science Library

    Nishioka, Kentaro; Shimizu, Shinichi; Kinoshita, Rumiko; Inoue, Tetsuya; Onodera, Shunsuke; Yasuda, Koichi; Harada, Keiichi; Nishikawa, Yukiko; Onimaru, Rikiya; Shirato, Hiroki

    2013-01-01

    In-room cone-beam computerized tomography (CBCT) imaging is a promising method to reduce setup errors, especially in organs such as the bladder that often have large intrafractional variations due to organ movement...

  4. Anthropometric analysis of maxillary anterior buccal bone of Korean adults using cone-beam CT

    National Research Council Canada - National Science Library

    Lee, Seung-Lok; Kim, Hee-Jung; Son, Mee-Kyoung; Chung, Chae-Heon

    2010-01-01

    The aim of this study was to evaluate the thickness of buccal and palatal alveolar bone and buccal bony curvature below root apex in maxillary anterior teeth of Korean adults using Cone-beam CT images...

  5. Cone beam computed tomography and applicability in Dentistry – literature review

    National Research Council Canada - National Science Library

    Fabiana Caroline da Silva; Ilana Sanamaika Queiroga Bezerra; Nelson Luis Barbosa Rebellato; Antonio Adilson Soares de Lima

    2013-01-01

    .... The cone beam computed tomography (CBCT) represents a valuable resource in dental practice because it allows the establishment of a precise treatment plan by means of diagnostic imaging. Objective...

  6. Ultrafast cone-beam CT scatter correction with GPU-based Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Yuan Xu

    2014-03-01

    Full Text Available Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT. We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstruction within 30 seconds.Methods: The method consists of six steps: 1 FDK reconstruction using raw projection data; 2 Rigid Registration of planning CT to the FDK results; 3 MC scatter calculation at sparse view angles using the planning CT; 4 Interpolation of the calculated scatter signals to other angles; 5 Removal of scatter from the raw projections; 6 FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC noise from the simulated scatter images caused by low photon numbers. The method is validated on one simulated head-and-neck case with 364 projection angles.Results: We have examined variation of the scatter signal among projection angles using Fourier analysis. It is found that scatter images at 31 angles are sufficient to restore those at all angles with < 0.1% error. For the simulated patient case with a resolution of 512 × 512 × 100, we simulated 5 × 106 photons per angle. The total computation time is 20.52 seconds on a Nvidia GTX Titan GPU, and the time at each step is 2.53, 0.64, 14.78, 0.13, 0.19, and 2.25 seconds, respectively. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU.Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. It accomplished the whole procedure of scatter correction and reconstruction within 30 seconds.----------------------------Cite this

  7. Histological validation of cone-beam computed tomography versus laser fluorescence and conventional diagnostic methods for occlusal caries detection.

    Science.gov (United States)

    Ozturk, Elif; Sinanoglu, Alper

    2015-02-01

    The purpose of this study was to compare the validity of visual (VE), radiological (RE), cone beam computed tomography (CBCT), and laser fluorescence (LFE) examination methods for the detection of the occlusal noncavitated caries in permanent posterior teeth. Two examiners assessed 121 selected sites on the occlusal surfaces of 44 molar teeth by visual (International Caries Assessment and Detection System II [ICDAS]), radiographic (bite-wing projection) cone-beam computed tomography, and laser fluorescence (DIAGNOdent Pen) examination methods. After a 1-week interval, each measurement was repeated by two examiners. Then, the teeth were sectioned, and histological evaluation was performed, which serves as the gold standard. The lesion depths were classified and correlated with the methods evaluated for validation. The intra- and inter-examiner reliability (sensitivity, specificity) and reproducibility of all examination methods were calculated using a weighted Cohen's κ statistic. The correlation between the examination methods was determined using receiver operating characteristic (ROC) analysis indicating the area under the curve (AUC). CBCT exhibited excellent intra-examiner (0.76 for examiner 1, 0.78 for examiner 2) and fair to good inter-examiner (0.63 for the first, 0.64 for the second measurements) reproducibility. The intra-examiner reproducibility was excellent for the LFE method according to the weighted κ values of examiners 1 (0.90) and 2 (0.79). Among the combined methods, the highest AUC values (0.81-0.95) were obtained for the CBCT examination method performed by the two examiners at both the first and second measurements. Cone beam computed tomography showed better performance than other diagnostic methods.

  8. Directional sinogram interpolation for motion weighted 4D cone-beam CT reconstruction

    Science.gov (United States)

    Zhang, Hua; Kruis, Matthijs; Sonke, Jan-Jakob

    2017-03-01

    The image quality of respiratory sorted four-dimensional (4D) cone-beam (CB) computed tomography (CT) is often limited by streak artifacts due to insufficient projections. A motion weighted reconstruction (MWR) method is proposed to decrease streak artifacts and improve image quality. Firstly, respiratory correlated CBCT projections were interpolated by directional sinogram interpolation (DSI) to generate additional CB projections for each phase and subsequently reconstructed. Secondly, local motion was estimated by deformable image registration of the interpolated 4D CBCT. Thirdly, a regular 3D FDK CBCT was reconstructed from the non-interpolated projections. Finally, weights were assigned to each voxel, based on the local motion, and then were used to combine the 3D FDK CBCT and interpolated 4D CBCT to generate the final 4D image. MWR method was compared with regular 4D CBCT scans as well as McKinnon and Bates (MKB) based reconstructions. Comparisons were made in terms of (1) comparing the steepness of an extracted profile from the boundary of the region-of-interest (ROI), (2) contrast-to-noise ratio (CNR) inside certain ROIs, and (3) the root-mean-square-error (RMSE) between the planning CT and CBCT inside a homogeneous moving region. Comparisons were made for both a phantom and four patient scans. In a 4D phantom, RMSE were reduced by 24.7% and 38.7% for MKB and MWR respectively, compared to conventional 4D CBCT. Meanwhile, interpolation induced blur was minimal in static regions for MWR based reconstructions. In regions with considerable respiratory motion, image blur using MWR is less than the MKB and 3D Feldkamp (FDK) methods. In the lung cancer patients, average CNRs of MKB, DSI and MWR improved by a factor 1.7, 2.8 and 3.5 respectively relative to 4D FDK. MWR effectively reduces RMSE in 4D cone-beam CT and improves the image quality in both the static and respiratory moving regions compared to 4D FDK and MKB methods.

  9. Case report: Cone-beam ct imaging in the management of a double tooth.

    Science.gov (United States)

    Lucey, S; Heath, N; Welbury, R R; Wright, G

    2009-11-01

    The diagnosis and management strategies of double teeth have largely relied on clinical examination and conventional radiographic findings. Cone-Beam Computed Tomography (Cone-beam CT) was developed in the late 1990's and, therefore, is a relatively recent addition to the imaging armamentarium for use in Maxillofacial Radiology. There have been no publications in the dental literature demonstrating the use of Cone-beam CT or 3D stereolithography in the diagnosis and surgical planning of the management of double teeth. An 11 year old girl presented with a double left lateral maxillary incisor. Conventional plain film radiography failed to provide the requisite information for pre-operative planning. Cone-beam Computed Tomography (Cone-beam CT) allowed determination of location of fusion, three-dimensional (3D) visualisation of pulpal anatomy and the construction of a 3D stereolithographic model for surgical planning. The double tooth was surgically divided in situ under local analgesia. The redundant distal unit was extracted and the residual mesial unit built up in composite resin following physiological mesial drift of displaced maxillary left canine. No endodontic therapy was required. At a 10-month follow-up visit, clinical and radiographic vitality and success was noted. The great amount of radiological information which Cone-beam CT can offer not only improves pre-operative and surgical planning, but the 3D models provided can be used to further educate and inform patients and guardians in the management of double teeth.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-15

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

  11. Comparison of cone beam computed tomography imaging with physical measures.

    Science.gov (United States)

    Stratemann, S A; Huang, J C; Maki, K; Miller, A J; Hatcher, D C

    2008-02-01

    The goal of this study was to determine the accuracy of measuring linear distances between landmarks commonly used in orthodontic analysis on a human skull using two cone beam CT (CBCT) systems. Measurements of length were taken using volumetric data from two CBCT systems and were compared with physical measures using a calliper applied to one human adult skull. Landmarks were identified with chromium steel balls embedded at 32 cranial and 33 mandibular landmarks and the linear measures were taken with a digital calliper. The skull was then scanned with two different CBCT systems: the NewTom QR DVT 9000 (Aperio Inc, Sarasota, FL) and the Hitachi MercuRay (Hitachi Medico Technology, Tokyo, Japan). CT data including the landmark point data were threshold segmented using CyberMed's CB Works software (CB Works 1.0, CyberMed Inc., Seoul, Korea). The resulting segmentations were exported from CB Works as VRML (WRL) files to Amira software (Amira 3.1, Mercury Computer Systems GmbH, Berlin, Germany). The error was small compared with the gold standard of the physical calliper measures for both the NewTom (0.07+/-0.41 mm) and CB MercuRay (0.00+/-0.22 mm) generated data. Absolute error to the gold standard was slightly positive, indicating minor compression relative to the calliper measurement. The error was slightly smaller in the CB MercuRay than in the NewTom, probably related to a broader greyscale range for describing beam attenuation in 12-bit vs 8-bit data. The volumetric data rendered with both CBCT systems provided highly accurate data compared with the gold standard of physical measures directly from the skulls, with less than 1% relative error.

  12. Automatic segmentation of maxillofacial cysts in cone beam CT images.

    Science.gov (United States)

    Abdolali, Fatemeh; Zoroofi, Reza Aghaeizadeh; Otake, Yoshito; Sato, Yoshinobu

    2016-05-01

    Accurate segmentation of cysts and tumors is an essential step for diagnosis, monitoring and planning therapeutic intervention. This task is usually done manually, however manual identification and segmentation is tedious. In this paper, an automatic method based on asymmetry analysis is proposed which is general enough to segment various types of jaw cysts. The key observation underlying this approach is that normal head and face structure is roughly symmetric with respect to midsagittal plane: the left part and the right part can be divided equally by an axis of symmetry. Cysts and tumors typically disturb this symmetry. The proposed approach consists of three main steps as follows: At first, diffusion filtering is used for preprocessing and symmetric axis is detected. Then, each image is divided into two parts. In the second stage, free form deformation (FFD) is used to correct slight displacement of corresponding pixels of the left part and a reflected copy of the right part. In the final stage, intensity differences are analyzed and a number of constraints are enforced to remove false positive regions. The proposed method has been validated on 97 Cone Beam Computed Tomography (CBCT) sets containing various jaw cysts which were collected from various image acquisition centers. Validation is performed using three similarity indicators (Jaccard index, Dice's coefficient and Hausdorff distance). The mean Dice's coefficient of 0.83, 0.87 and 0.80 is achieved for Radicular, Dentigerous and KCOT classes, respectively. For most of the experiments done, we achieved high true positive (TP). This means that a large number of cyst pixels are correctly classified. Quantitative results of automatic segmentation show that the proposed method is more effective than one of the recent methods in the literature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-15

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

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

    Directory of Open Access Journals (Sweden)

    Kuo Men

    2015-01-01

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

  15. A web-based instruction module for interpretation of craniofacial cone beam CT anatomy.

    Science.gov (United States)

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

    2007-09-01

    To develop a web-based module for learner instruction in the interpretation and recognition of osseous anatomy on craniofacial cone-beam CT (CBCT) images. Volumetric datasets from three CBCT systems were acquired (i-CAT, NewTom 3G and AccuiTomo FPD) for various subjects using equipment-specific scanning protocols. The datasets were processed using multiple software to provide two-dimensional (2D) multiplanar reformatted (MPR) images (e.g. sagittal, coronal and axial) and three-dimensional (3D) visual representations (e.g. maximum intensity projection, minimum intensity projection, ray sum, surface and volume rendering). Distinct didactic modules which illustrate the principles of CBCT systems, guided navigation of the volumetric dataset, and anatomic correlation of 3D models and 2D MPR graphics were developed using a hybrid combination of web authoring and image analysis techniques. Interactive web multimedia instruction was facilitated by the use of dynamic highlighting and labelling, and rendered video illustrations, supplemented with didactic textual material. HTML coding and Java scripting were heavily implemented for the blending of the educational modules. An interactive, multimedia educational tool for visualizing the morphology and interrelationships of osseous craniofacial anatomy, as depicted on CBCT MPR and 3D images, was designed and implemented. The present design of a web-based instruction module may assist radiologists and clinicians in learning how to recognize and interpret the craniofacial anatomy of CBCT based images more efficiently.

  16. GPU-based Cone Beam CT Reconstruction via Total Variation Regularization

    CERN Document Server

    Jia, Xun; Lewis, John; Li, Ruijiang; Gu, Xuejun; Men, Chunhua; Jiang, Steve B

    2010-01-01

    Cone-beam CT (CBCT) reconstruction is of central importance in image guided radiation therapy due to its broad applications in many clinical contexts. However, the high image dose in CBCT scans is a clinical concern, especially when it is used repeatedly for patient setup purposes before each radiotherapy treatment fraction. A desire for lower imaging does has motivated a vast amount of interest in the CBCT reconstruction based on a small number of X-ray projections. Recently, advances in image processing and compressed sensing have led to tremendous success in recovering signals based on extremely low sampling rates, laying the mathematical foundation for reconstructing CBCT from few projections. In this paper, we present our recent development on a GPU-based iterative algorithm for the highly under-sampled CBCT reconstruction problem. We considered an energy functional consisting of a data fidelity term and a regularization term of a total variation norm. In order to solve our model, we developed a modified...

  17. Respiratory signal generation for retrospective gating of cone-beam CT images

    Science.gov (United States)

    Wiesner, Stefan; Yaniv, Ziv

    2008-03-01

    We are currently investigating the acquisition of 4D cone-beam CT data using retrospective gating of the X-ray projection images. This approach requires a respiratory signal that is synchronized with image acquisition. To obtain such a signal we propose to use a spherical fiducial attached to the patient's skin surface such that it is visible in the images. A region of interest containing the fiducial is manually identified in an initial image and is then automatically detected in all other images. Subsequently, we perform an approximate spatial (3D) reconstruction of the marker location from its 2D locations. Finally, we compute a respiratory signal by projecting the 3D points onto the major axis estimated via principle component analysis. As this respiratory signal was obtained from the fiducial location in each of the images it is implicitly synchronized with image acquisition. We evaluate the robustness of our fiducial detection using an anthropomorphic respiratory phantom. To evaluate the quality of the estimated respiratory signal we use a motion platform that follows the respiratory motion obtained by tracking the skin surface of a volunteer. We show that our method generates a respiratory signal that is in phase with the ground truth signal, but suffers from inaccuracies in amplitude close to the anterior-posterior imaging setup where the primary direction of motion is perpendicular to the image plane. Thus, our method should only be used for phase based retrospective gating.

  18. Method of visualisation influences accuracy of measurements in cone-beam computed tomography.

    Science.gov (United States)

    Patcas, Raphael; Angst, Christine; Kellenberger, Christian J; Schätzle, Marc A; Ullrich, Oliver; Markic, Goran

    2015-09-01

    This study evaluated the potential impact of different visualisation methods of cone-beam computed tomography (CBCT) on the accuracy of linear measurements of calcified structures, and assessed their interchangeability. High resolution (0.125 mm voxel) CBCT scans were obtained from eight cadaveric heads. The distance between the alveolar bone ridge and the incisal edge was determined for all mandibular incisors and canines, both anatomically and with measurements based on the following five CBCT visualisation methods: isosurface, direct volume rendering, multiplanar reformatting (MPR), maximum intensity projection of the volume of interest (VOIMIP), and average intensity projection of the volume of interest (VOIAvIP). All radiological methods were tested for repeatability and compared with anatomical results for accuracy, and limits of agreement were established. Interchangeability was evaluated by reviewing disparities between the methods and disclosing deterministic differences. Fine intra- and inter-observer repeatability was asserted for all visualisation methods (intraclass correlation coefficient ≤0.81). Measurements were most accurate when performed on MPR images and performed most disappointingly on isosurface-based images. Direct volume rendering, VOIMIP and VOIAvIP achieved acceptable results. It can be concluded that visualisation methods influence the accuracy of CBCT measurements. The isosurface viewing method is not recommended, and multiplanar reformatted images should be favoured for linear measurements of calcified structures. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  20. Optimizing the reconstruction filter in cone-beam CT to improve periodontal ligament space visualization: An in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Houno, Yuuki; Kodera, Yoshie [Graduate School of Medicine, Nagoya University, Nagoya (Japan); Hishikawa, Toshimitsu; Naitoh, Munetaka; Mitani, Akio; Noguchi, Toshihide; Ariji, Eiichiro [Aichi Gakuin University, Nisshin (Japan); Gotoh, Kenichi [Div. of Radiology, Dental Hospital, Aichi Gakuin University, Nisshin (Japan)

    2017-09-15

    Evaluation of alveolar bone is important in the diagnosis of dental diseases. The periodontal ligament space is difficult to clearly depict in cone-beam computed tomography images because the reconstruction filter conditions during image processing cause image blurring, resulting in decreased spatial resolution. We examined different reconstruction filters to assess their ability to improve spatial resolution and allow for a clearer visualization of the periodontal ligament space. Cone-beam computed tomography projections of 2 skull phantoms were reconstructed using 6 reconstruction conditions and then compared using the Thurstone paired comparison method. Physical evaluations, including the modulation transfer function and the Wiener spectrum, as well as an assessment of space visibility, were undertaken using experimental phantoms. Image reconstruction using a modified Shepp-Logan filter resulted in better sensory, physical, and quantitative evaluations. The reconstruction conditions substantially improved the spatial resolution and visualization of the periodontal ligament space. The difference in sensitivity was obtained by altering the reconstruction filter. Modifying the characteristics of a reconstruction filter can generate significant improvement in assessments of the periodontal ligament space. A high-frequency enhancement filter improves the visualization of thin structures and will be useful when accurate assessment of the periodontal ligament space is necessary.

  1. Optimizing Cone Beam Computed Tomography (CBCT) System for Image Guided Radiation Therapy

    Science.gov (United States)

    Park, Chun Joo

    Cone Beam Computed Tomography (CBCT) system is the most widely used imaging device in image guided radiation therapy (IGRT), where set of 3D volumetric image of patient can be reconstructed to identify and correct position setup errors prior to the radiation treatment. This CBCT system can significantly improve precision of on-line setup errors of patient position and tumor target localization prior to the treatment. However, there are still a number of issues that needs to be investigated with CBCT system such as 1) progressively increasing defective pixels in imaging detectors by its frequent usage, 2) hazardous radiation exposure to patients during the CBCT imaging, 3) degradation of image quality due to patients' respiratory motion when CBCT is acquired and 4) unknown knowledge of certain anatomical features such as liver, due to lack of soft-tissue contrast which makes tumor motion verification challenging. In this dissertation, we explore on optimizing the use of cone beam computed tomography (CBCT) system under such circumstances. We begin by introducing general concept of IGRT. We then present the development of automated defective pixel detection algorithm for X-ray imagers that is used for CBCT imaging using wavelet analysis. We next investigate on developing fast and efficient low-dose volumetric reconstruction techniques which includes 1) fast digital tomosynthesis reconstruction using general-purpose graphics processing unit (GPGPU) programming and 2) fast low-dose CBCT image reconstruction based on the Gradient-Projection-Barzilai-Borwein formulation (GP-BB). We further developed two efficient approaches that could reduce the degradation of CBCT images from respiratory motion. First, we propose reconstructing four dimensional (4D) CBCT and DTS using respiratory signal extracted from fiducial markers implanted in liver. Second, novel motion-map constrained image reconstruction (MCIR) is proposed that allows reconstruction of high quality and high phase

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

    Directory of Open Access Journals (Sweden)

    Fenglin Liu

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

  3. Dynamic Bowtie Filter for Cone-Beam/Multi-Slice CT

    Science.gov (United States)

    Liu, Fenglin; Yang, Qingsong; Cong, Wenxiang; Wang, Ge

    2014-01-01

    A pre-patient attenuator (“bowtie filter” or “bowtie”) is used to modulate an incoming x-ray beam as a function of the angle of the x-ray with respect to a patient to balance the photon flux on a detector array. While the current dynamic bowtie design is focused on fan-beam geometry, in this study we propose a methodology for dynamic bowtie design in multi-slice/cone-beam geometry. The proposed 3D dynamic bowtie is an extension of the 2D prior art. The 3D bowtie consists of a highly attenuating bowtie (HB) filled in with heavy liquid and a weakly attenuating bowtie (WB) immersed in the liquid of the HB. The HB targets a balanced flux distribution on a detector array when no object is in the field of view (FOV). The WB compensates for an object in the FOV, and hence is a scaled-down version of the object. The WB is rotated and translated in synchrony with the source rotation and patient translation so that the overall flux balance is maintained on the detector array. First, the mathematical models of different scanning modes are established for an elliptical water phantom. Then, a numerical simulation study is performed to compare the performance of the scanning modes in the cases of the water phantom and a patient cross-section without any bowtie and with a dynamic bowtie. The dynamic bowtie can equalize the numbers of detected photons in the case of the water phantom. In practical cases, the dynamic bowtie can effectively reduce the dynamic range of detected signals inside the FOV. Furthermore, the WB can be individualized using a 3D printing technique as the gold standard. We have extended the dynamic bowtie concept from 2D to 3D by using highly attenuating liquid and moving a scale-reduced negative copy of an object being scanned. Our methodology can be applied to reduce radiation dose and facilitate photon-counting detection. PMID:25051067

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-09-15

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

  5. Evaluation of tilted cone-beam CT orbits in the development of a dedicated hybrid mammotomograph

    Energy Technology Data Exchange (ETDEWEB)

    Madhav, P; Crotty, D J; Tornai, M P [Department of Radiology, Duke University Medical Center, Durham, NC 27710 (United States); McKinley, R L [Zumatek Incorporated, Chapel Hill, NC 27519 (United States)], E-mail: priti.madhav@duke.edu

    2009-06-21

    A compact dedicated 3D breast SPECT-CT (mammotomography) system is currently under development. In its initial prototype, the cone-beam CT sub-system is restricted to a fixed-tilt circular rotation around the patient's pendant breast. This study evaluated stationary-tilt angles for the CT sub-system that will enable maximal volumetric sampling and viewing of the breast and chest wall. Images of geometric/anthropomorphic phantoms were acquired using various fixed-tilt circular and 3D sinusoidal trajectories. The iteratively reconstructed images showed more distortion and attenuation coefficient inaccuracy from tilted cone-beam orbits than from the complex trajectory. Additionally, line profiles illustrated cupping artifacts in planes distal to the central plane of the tilted cone-beam, otherwise not apparent for images acquired with complex trajectories. This indicates that undersampled cone-beam data may be an additional cause of cupping artifacts. High-frequency objects could be distinguished for all trajectories, but their shapes and locations were corrupted by out-of-plane frequency information. Although more acrylic balls were visualized with a fixed-tilt and nearly flat cone-beam at the posterior of the breast, 3D complex trajectories have less distortion and more complete sampling throughout the reconstruction volume. While complex trajectories would ideally be preferred, negatively fixed-tilt source-detector configuration demonstrates minimally distorted patient images.

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

    Science.gov (United States)

    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.

  7. 3D Alternating Direction TV-Based Cone-Beam CT Reconstruction with Efficient GPU Implementation

    Directory of Open Access Journals (Sweden)

    Ailong Cai

    2014-01-01

    Full Text Available Iterative image reconstruction (IIR with sparsity-exploiting methods, such as total variation (TV minimization, claims potentially large reductions in sampling requirements. However, the computation complexity becomes a heavy burden, especially in 3D reconstruction situations. In order to improve the performance for iterative reconstruction, an efficient IIR algorithm for cone-beam computed tomography (CBCT with GPU implementation has been proposed in this paper. In the first place, an algorithm based on alternating direction total variation using local linearization and proximity technique is proposed for CBCT reconstruction. The applied proximal technique avoids the horrible pseudoinverse computation of big matrix which makes the proposed algorithm applicable and efficient for CBCT imaging. The iteration for this algorithm is simple but convergent. The simulation and real CT data reconstruction results indicate that the proposed algorithm is both fast and accurate. The GPU implementation shows an excellent acceleration ratio of more than 100 compared with CPU computation without losing numerical accuracy. The runtime for the new 3D algorithm is about 6.8 seconds per loop with the image size of 256×256×256 and 36 projections of the size of 512×512.

  8. GPU-based Iterative Cone Beam CT Reconstruction Using Tight Frame Regularization

    CERN Document Server

    Jia, Xun; Lou, Yifei; Jiang, Steve B

    2010-01-01

    X-ray imaging dose from serial cone-beam CT (CBCT) scans raises a clinical concern in most image guided radiation therapy procedures. It is the goal of this paper to develop a fast GPU-based algorithm to reconstruct high quality CBCT images from undersampled and noisy projection data so as to lower the imaging dose. For this purpose, we have developed an iterative tight frame (TF) based CBCT reconstruction algorithm. A condition that a real CBCT image has a sparse representation under a TF basis is imposed in the iteration process as regularization to the solution. To speed up the computation, a multi-grid method is employed. Our GPU implementation has achieved high computational efficiency and a CBCT image of resolution 512x512x70 can be reconstructed in about ~139 sec. We have tested our algorithm on a digital NCAT phantom and a physical Catphan phantom. It is found that our TF-based algorithm leads to much higher CBCT quality than those obtained from a conventional FDK algorithm in the context of undersamp...

  9. High quality 4D cone-beam CT reconstruction using motion-compensated total variation regularization

    Science.gov (United States)

    Zhang, Hua; Ma, Jianhua; Bian, Zhaoying; Zeng, Dong; Feng, Qianjin; Chen, Wufan

    2017-04-01

    Four dimensional cone-beam computed tomography (4D-CBCT) has great potential clinical value because of its ability to describe tumor and organ motion. But the challenge in 4D-CBCT reconstruction is the limited number of projections at each phase, which result in a reconstruction full of noise and streak artifacts with the conventional analytical algorithms. To address this problem, in this paper, we propose a motion compensated total variation regularization approach which tries to fully explore the temporal coherence of the spatial structures among the 4D-CBCT phases. In this work, we additionally conduct motion estimation/motion compensation (ME/MC) on the 4D-CBCT volume by using inter-phase deformation vector fields (DVFs). The motion compensated 4D-CBCT volume is then viewed as a pseudo-static sequence, of which the regularization function was imposed on. The regularization used in this work is the 3D spatial total variation minimization combined with 1D temporal total variation minimization. We subsequently construct a cost function for a reconstruction pass, and minimize this cost function using a variable splitting algorithm. Simulation and real patient data were used to evaluate the proposed algorithm. Results show that the introduction of additional temporal correlation along the phase direction can improve the 4D-CBCT image quality.

  10. Quantitative analysis of periapical lesions on cone beam computed tomograph and periapical radiograph

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hoa; Lee, Wan; Kim, Kyung Soo; Roh, Young Chea; Lee, Byung Do [Department of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Kim, De Sok [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Deajeon (Korea, Republic of)

    2009-03-15

    To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

  11. Multi-core parallel reconstruction method for cone-beam computed tomography

    Science.gov (United States)

    Li, Mingjun; Zhang, Dinghua; Huang, Kuidong; Yu, Qingchao; Zhang, Shunli

    2009-10-01

    In the application of nondestructive testing and evaluation, this paper mainly deals with the problem of improving the image reconstruction speed in cone beam computed tomography (CBCT). FDK algorithm is a time costing method for CBCT image reconstruction, due to the voluminous data and long operating process. With the help of data organization and task distribution, we improved the SIMD instructions in Z-line data first reconstruction algorithm, which is an improved method based on the FDK algorithm. And then, we run it parallelized with multi-core technology and a certain divide-and-conquer strategy to get a fast reconstruction speed in CBCT. Finally, we evaluate the effectiveness of our method from a numerical test of a blade model on an 8-core computer with four channel memory. Our method has got a considerable speedup ratio of 217.22 to the FDK algorithm, and implemented the back-projection process of reconstructing the inscribed cylinder of 5123 reconstruction space in about 30 seconds. It has got the same image quality with the Z-line data first method, which retains the computational precision with FDK algorithm. Basically, our method has met the requirement of real-time reconstruction.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2012-09-15

    This study investigated the relationship between the roots of the maxillary molars and the maxillary sinus using cone beam computed tomography (CBCT), and measured the distances between the roots of the maxillary molars and the sinus floor as well as the thickness of the bone between the root and the alveolar cortical plate. The study sample consisted of 83 patients with normally erupted bilateral maxillary first and second molars. A total of 332 maxillary molars were examined using CBCT images. The vertical relationship of each root with the maxillary sinus was classified into four types on CBCT cross-sectional images. The distance between the sinus floor and root and the bone thickness between the root and alveolar cortical plate were measured. In the buccal roots of the maxillary molars, a root protruding into the sinus occurred most frequently. A root projecting laterally along the sinus cavity was most common in the palatal roots of the maxillary first molars. The mesiobuccal roots of the maxillary second molar were closest to the sinus. The mesiobuccal roots of the first molars were closest to the cortical plate. The relationship between the roots of the maxillary molars and the sinus differed between the buccal and palatal roots. A root protruding into the sinus occurred more frequent in the buccal roots of the maxillary molars. The mesiobuccal root of the maxillary second molar was closest to the maxillary sinus floor and farthest from the alveolar cortical plate.

  13. Cone-beam CT for breast imaging: Radiation dose, breast coverage, and image quality.

    Science.gov (United States)

    O'Connell, Avice; Conover, David L; Zhang, Yan; Seifert, Posy; Logan-Young, Wende; Lin, Chuen-Fu Linda; Sahler, Lawrence; Ning, Ruola

    2010-08-01

    The primary objectives of this pilot study were to evaluate the radiation dose, breast coverage, and image quality of cone-beam breast CT compared with a conventional mammographic examination. Image quality analysis was focused on the concordance of cone-beam breast CT with conventional mammography in terms of mammographic findings. This prospective study was performed from July 2006 through August 2008. Twenty-three women were enrolled who met the inclusion criteria, which were age 40 years or older with final BI-RADS assessment category 1 or 2 lesions on conventional mammograms within the previous 6 months. The breasts were imaged with a flat-panel detector-based cone-beam CT system, and the images were reviewed with a 3D visualization system. Cone-beam breast CT image data sets and the corresponding mammograms were reviewed by three qualified mammographers. The parameters assessed and compared in this pilot study were radiation dose, breast tissue coverage, and image quality, including detectability of masses and calcifications. The mammograms and cone-beam breast CT images were independently reviewed side by side, and the reviewers were not blinded to the other technique. The observed agreement and Cohen's kappa were used to evaluate agreement between the mammographic and cone-beam breast CT findings and interobserver agreement. Each subject responded to a questionnaire on multiple parameters, including comfort of the cone-beam breast CT examination compared with mammography. For a conventional mammographic examination, the average glandular radiation dose ranged from 2.2 to 15 mGy (mean, 6.5 [SD, 2.9] mGy). For cone-beam breast CT, the average glandular dose ranged from 4 to 12.8 mGy (mean, 8.2 [SD, 1.4] mGy). The average glandular dose from cone-beam breast CT was generally within the range of that from conventional mammography. For heterogeneously dense and extremely dense breasts, the difference between the mean dose of conventional mammography and that of

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

    Directory of Open Access Journals (Sweden)

    Ching-Ching Yang

    Full Text Available Scatter is a very important artifact causing factor in dental cone-beam CT (CBCT, which has a major influence on the detectability of details within images. This work aimed to improve the image quality of dental CBCT through scatter correction.Scatter was estimated in the projection domain from the low frequency component of the difference between the raw CBCT projection and the projection obtained by extrapolating the model fitted to the raw projections acquired with 2 different sizes of axial field-of-view (FOV. The function for curve fitting was optimized by using Monte Carlo simulation. To validate the proposed method, an anthropomorphic phantom and a water-filled cylindrical phantom with rod inserts simulating different tissue materials were scanned using 120 kVp, 5 mA and 9-second scanning time covering an axial FOV of 4 cm and 13 cm. The detectability of the CT image was evaluated by calculating the contrast-to-noise ratio (CNR.Beam hardening and cupping artifacts were observed in CBCT images without scatter correction, especially in those acquired with 13 cm FOV. These artifacts were reduced in CBCT images corrected by the proposed method, demonstrating its efficacy on scatter correction. After scatter correction, the image quality of CBCT was improved in terms of target detectability which was quantified as the CNR for rod inserts in the cylindrical phantom.Hopefully the calculations performed in this work can provide a route to reach a high level of diagnostic image quality for CBCT imaging used in oral and maxillofacial structures whilst ensuring patient dose as low as reasonably achievable, which may ultimately make CBCT scan a reliable and safe tool in clinical practice.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

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

  17. Treatment of a Four-Rooted Maxillary Second Molar Detected with Cone-Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Nahid Mohammadzade Akhlaghi

    2017-08-01

    Full Text Available The significance of clinician’s knowledge about root canal anatomy and its possible variations cannot be overlooked. In some cases, taking advantage of complementary imaging techniques can help achieve a perfect flawless endodontic treatment. This article reports endodontic management of a second maxillary molar that had an uncommon anatomy of the chamber floor. After obtaining a cone-beam computed tomography (CBCT image, the presence of a second palatal root was confirmed. All four roots were treated and patient’s symptoms were resolved.Keywords: Cone-Beam Computed Tomography; Root Canal Therapy; Tooth Root

  18. 3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification

    OpenAIRE

    Hana Eliášová; Taťjana Dostálová

    2017-01-01

    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 optica...

  19. Microfabricated, 94 GHz, 25 W, Helical Traveling Wave Tube Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Teraphysics Corporation completed the Phase I objectives for the electrical design of a 94 GHz, 26 W TWT with 53% overall efficiency, including the helical circuit...

  20. TU-EF-207-05: Dedicated Cone-beam Breast CT

    Energy Technology Data Exchange (ETDEWEB)

    Vedantham, S. [Univ. of Massachusetts Medical School (United States)

    2015-06-15

    mode due to lower photon fluence per projection. This may require fast-frame acquisition and symmetric or asymmetric pixel binning in some systems. Recent studies investigated the performance of increased conversion layer thickness for contrast-enhanced imaging of the breast in dual-energy acquisition mode. In other direct conversion detectors operating in the avalanche mode, sensitivities close to the single photon response are also explored for mammography and breast tomosynthesis. The potential advantages and challenges of this approach are described. Dedicated breast CT brings x-ray imaging of the breast to true tomographic 3D imaging. It can eliminate the tissue superposition problem and does not require physical compression of the breast. Using cone beam geometry and a flat-panel detector, several hundred projections are acquired and reconstructed to near isotropic voxels. Multiplanar reconstruction facilitates viewing the breast volume in any desired orientation. Ongoing clinical studies, the current state-of-the art, and research to advance the technology are described. Learning Objectives: To understand the ongoing developments in x-ray imaging of the breast To understand the approaches and applications of spectral mammography To understand the potential advantages of distributed x-ray source arrays for digital breast tomosynthesis To understand the ongoing developments in detector technology for digital mammography and breast tomosynthesis To understand the current state-of-the-art for dedicated cone-beam breast CT and research to advance the technology. Research collaboration with Koning Corporation.

  1. An image-based method to synchronize cone-beam CT and optical surface tracking.

    Science.gov (United States)

    Fassi, Aurora; Schaerer, Joël; Riboldi, Marco; Sarrut, David; Baroni, Guido

    2015-03-08

    The integration of in-room X-ray imaging and optical surface tracking has gained increasing importance in the field of image guided radiotherapy (IGRT). An essential step for this integration consists of temporally synchronizing the acquisition of X-ray projections and surface data. We present an image-based method for the synchronization of cone-beam computed tomography (CBCT) and optical surface systems, which does not require the use of additional hardware. The method is based on optically tracking the motion of a component of the CBCT/gantry unit, which rotates during the acquisition of the CBCT scan. A calibration procedure was implemented to relate the position of the rotating component identified by the optical system with the time elapsed since the beginning of the CBCT scan, thus obtaining the temporal correspondence between the acquisition of X-ray projections and surface data. The accuracy of the proposed synchronization method was evaluated on a motorized moving phantom, performing eight simultaneous acquisitions with an Elekta Synergy CBCT machine and the AlignRT optical device. The median time difference between the sinusoidal peaks of phantom motion signals extracted from the synchronized CBCT and AlignRT systems ranged between -3.1 and 12.9 msec, with a maximum interquartile range of 14.4 msec. The method was also applied to clinical data acquired from seven lung cancer patients, demonstrating the potential of the proposed approach in estimating the individual and daily variations in respiratory parameters and motion correlation of internal and external structures. The presented synchronization method can be particularly useful for tumor tracking applications in extracranial radiation treatments, especially in the field of patient-specific breathing models, based on the correlation between internal tumor motion and external surface surrogates.

  2. Correction of patient motion in cone-beam CT using 3D–2D registration

    Science.gov (United States)

    Ouadah, S.; Jacobson, M.; Stayman, J. W.; Ehtiati, T.; Weiss, C.; Siewerdsen, J. H.

    2017-12-01

    Cone-beam CT (CBCT) is increasingly common in guidance of interventional procedures, but can be subject to artifacts arising from patient motion during fairly long (~5–60 s) scan times. We present a fiducial-free method to mitigate motion artifacts using 3D–2D image registration that simultaneously corrects residual errors in the intrinsic and extrinsic parameters of geometric calibration. The 3D–2D registration process registers each projection to a prior 3D image by maximizing gradient orientation using the covariance matrix adaptation-evolution strategy optimizer. The resulting rigid transforms are applied to the system projection matrices, and a 3D image is reconstructed via model-based iterative reconstruction. Phantom experiments were conducted using a Zeego robotic C-arm to image a head phantom undergoing 5–15 cm translations and 5–15° rotations. To further test the algorithm, clinical images were acquired with a CBCT head scanner in which long scan times were susceptible to significant patient motion. CBCT images were reconstructed using a penalized likelihood objective function. For phantom studies the structural similarity (SSIM) between motion-free and motion-corrected images was  >0.995, with significant improvement (p  quality after motion correction. This indicates that the 3D–2D registration method could provide a useful approach to motion artifact correction under assumptions of local rigidity, as in the head, pelvis, and extremities. The method is highly parallelizable, and the automatic correction of residual geometric calibration errors provides added benefit that could be valuable in routine use.

  3. Parameter selection in limited data cone-beam CT reconstruction using edge-preserving total variation algorithms

    Science.gov (United States)

    Lohvithee, Manasavee; Biguri, Ander; Soleimani, Manuchehr

    2017-12-01

    There are a number of powerful total variation (TV) regularization methods that have great promise in limited data cone-beam CT reconstruction with an enhancement of image quality. These promising TV methods require careful selection of the image reconstruction parameters, for which there are no well-established criteria. This paper presents a comprehensive evaluation of parameter selection in a number of major TV-based reconstruction algorithms. An appropriate way of selecting the values for each individual parameter has been suggested. Finally, a new adaptive-weighted projection-controlled steepest descent (AwPCSD) algorithm is presented, which implements the edge-preserving function for CBCT reconstruction with limited data. The proposed algorithm shows significant robustness compared to three other existing algorithms: ASD-POCS, AwASD-POCS and PCSD. The proposed AwPCSD algorithm is able to preserve the edges of the reconstructed images better with fewer sensitive parameters to tune.

  4. Correlating cone beam CT results with temporomandibular joint pain of osteoarthritic origin.

    Science.gov (United States)

    Palconet, G; Ludlow, J B; Tyndall, D A; Lim, P F

    2012-02-01

    The purpose of this study was to determine whether bony changes in temporomandibular joint (TMJ) osteoarthritis (OA) is correlated with pain and other clinical signs and symptoms. Clinical data and cone beam CT (CBCT) images of 30 patients with TMJ OA were analysed. The criteria of Koyama et al (Koyama J, Nishiyama H, Hayashi T. Follow-up study of condylar bony changes using helical computed tomography in patients with temporomandibular disorder. Dentomaxillofac Radiol 2007; 36: 472-477.) and Ahmad et al [Ahmad M, Hollender L, Anderson Q, Kartha K, Ohrbach R, Truelove EL, et al. Research diagnostic criteria for temporomandibular disorders (RDC/TMD): development of image analysis criteria and examiner reliability for image analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 107: 844-860.] were used to classify the condyles observed on the CBCT. Clinical measures included self-reported pain, mandibular range of motion, TMJ sound, pain on palpation of the TMJ and masticatory muscles, and pain on jaw function. Generalized linear modelling was used to correlate the clinical and radiographic findings and Spearman's rho was used to correlate the two classification systems. There was poor correlation between the maximum condyle change and pain rating (Koyama: r² = 0.1443, p = 0.3995; Ahmad: r² = 0.0273, p = 0.9490), maximum mouth opening (Koyama: r² = 0.2910, p = 0.0629; Ahmad: r² = 0.2626, p = 0.0951), protrusion (Koyama: r² = 0.0875, p = 0.7001; Ahmad: r² = 0.1658, p = 0.3612), right lateral motion (Koyama: r² = 0.0394, p = 0.9093; Ahmad: r² = 0.0866, p = 0.6877) and left lateral motion (Koyama: r² = 0.0943, p = 0.6494; Ahmad: r² = 0.1704, p = 0.3236). Strong correlation was observed between Koyama et al's and Ahmad et al's classifications for average (r = 0.9216, p TMJ OA.

  5. Flat-panel cone-beam CT on a mobile isocentric C-arm for image-guided brachytherapy

    Science.gov (United States)

    Jaffray, David A.; Siewerdsen, Jeffrey H.; Edmundson, Gregory K.; Wong, John W.; Martinez, Alvaro A.

    2002-05-01

    Flat-panel imager (FPI) based cone-beam computed tomography (CBCT) is a strong candidate technology for intraoperative imaging in image-guided procedures such as brachytherapy. The soft-tissue imaging performance and potential navigational utility have been investigated using a computer-controlled benchtop system. These early results have driven the development of an isocentric C-arm for intraoperative FPI-CBCT, capable of collecting 94 projections over 180 degrees in 110 seconds. The C-arm system employs a large-area FPI with 400 micron pixel pitch and Gd2O2S:Tb scintillator. Image acquisition, processing and reconstruction are orchestrated under a single Windows-based application. Reconstruction is performed by a modified Feldkamp algorithm implemented on a high-speed reconstruction engine. Non-idealities in the source and detector trajectories during orbital motion has been quantified and tested for stability. Cone-beam CT imaging performance was tested through both quantitative and qualitative methods. The system MTF was measured using a wire phantom and demonstrated frequency pass out to 0.6 mm-1. Voxel noise was measured at 2.7 percent in a uniform 12 cm diameter water bath. Anatomical phantoms were employed for qualitative evaluation of the imaging performance. Images of an anaesthetized rabbit demonstrated the capacity of the system to discern soft-tissue structures within a living subject while offering sub-millimeter spatial resolution. The dose delivered in each of the imaging procedures was estimated from in-air exposure measurements to be approximately 0.1 cGy. Imaging studies of an anthropomorphic prostate phantom were performed with and without radioactive seeds. Soft-tissue imaging performance and seed detection appear to satisfy the imaging and navigation requirements for image-guided brachytherapy. These investigations advance the development and evaluation of such technology for image-guided surgical procedures, including brachytherapy

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

    NARCIS (Netherlands)

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

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

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    NARCIS (Netherlands)

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

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

  9. Comparison of five cone beam computed tomography systems for the detection of vertical root fractures

    NARCIS (Netherlands)

    Hassan, B.; Metska, M.E.; Ozok, A.R.; van der Stelt, P.; Wesselink, P.R.

    2010-01-01

    Introduction This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nandita S Gupta

    2015-01-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-15

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

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

    Science.gov (United States)

    Matenine, Dmitri; Mascolo-Fortin, Julia; Goussard, Yves; Després, Philippe

    2015-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Jerker Edén Strindberg

    2015-12-01

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

  17. Optimizing 4D cone-beam CT acquisition protocol for external beam radiotherapy.

    Science.gov (United States)

    Li, Tianfang; Xing, Lei

    2007-03-15

    Four-dimensional cone-beam computed tomography (4D-CBCT) imaging is sensitive to parameters such as gantry rotation speed, number of gantry rotations, X-ray pulse rate, and tube current, as well as a patient's breathing pattern. The aim of this study is to optimize the image acquisition on a patient-specific basis while minimizing the scan time and the radiation dose. More than 60 sets of 4D-CBCT images, each with a temporal resolution of 10 phases, were acquired using multiple-gantry rotation and slow-gantry rotation techniques. The image quality was quantified with a relative root mean-square error (RE) and correlated with various acquisition settings; specifically, varying gantry rotation speed, varying both the rotation speed and the number of rotations, and varying both the rotation speed and tube current to keep the radiation exposure constant. These experiments were repeated for three different respiratory periods. With similar radiation dose, 4D-CBCT images acquired with low current and low rotation speed have better quality over images obtained with high current and high rotation speed. In general, a one-rotation low-speed scan is superior to a two-rotation double-speed scan, even though they provide the same number of projections. Furthermore, it is found that the image quality behaves monotonically with the relative speed as defined by the gantry rotation speed and the patient respiratory period. The RE curves established in this work can be used to predict the 4D-CBCT image quality before a scan. This allows the acquisition protocol to be optimized individually to balance the desired quality with the associated scanning time and patient radiation dose.

  18. GPU-based iterative cone-beam CT reconstruction using tight frame regularization

    Science.gov (United States)

    Jia, Xun; Dong, Bin; Lou, Yifei; Jiang, Steve B.

    2011-07-01

    The x-ray imaging dose from serial cone-beam computed tomography (CBCT) scans raises a clinical concern in most image-guided radiation therapy procedures. It is the goal of this paper to develop a fast graphic processing unit (GPU)-based algorithm to reconstruct high-quality CBCT images from undersampled and noisy projection data so as to lower the imaging dose. For this purpose, we have developed an iterative tight-frame (TF)-based CBCT reconstruction algorithm. A condition that a real CBCT image has a sparse representation under a TF basis is imposed in the iteration process as regularization to the solution. To speed up the computation, a multi-grid method is employed. Our GPU implementation has achieved high computational efficiency and a CBCT image of resolution 512 × 512 × 70 can be reconstructed in ~5 min. We have tested our algorithm on a digital NCAT phantom and a physical Catphan phantom. It is found that our TF-based algorithm is able to reconstruct CBCT in the context of undersampling and low mAs levels. We have also quantitatively analyzed the reconstructed CBCT image quality in terms of the modulation-transfer function and contrast-to-noise ratio under various scanning conditions. The results confirm the high CBCT image quality obtained from our TF algorithm. Moreover, our algorithm has also been validated in a real clinical context using a head-and-neck patient case. Comparisons of the developed TF algorithm and the current state-of-the-art TV algorithm have also been made in various cases studied in terms of reconstructed image quality and computation efficiency.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Sung; Kim, Bok Yeol; Choi, Hwa Young [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul (Korea, Republic of); and others

    2015-03-15

    This study was performed to evaluate the feasibility of visualizing soft tissue lesions and vascular structures using contrast-enhanced cone-beam computed tomography (CE-CBCT) after the intravenous administration of a contrast medium in an animal model. CBCT was performed on six rabbits after a contrast medium was administered using an injection dose of 2 mL/kg body weight and an injection rate of 1 mL/s via the ear vein or femoral vein under general anesthesia. Artificial soft tissue lesions were created through the transplantation of autologous fatty tissue into the salivary gland. Volume rendering reconstruction, maximum intensity projection, and multiplanar reconstruction images were reconstructed and evaluated in order to visualize soft tissue contrast and vascular structures. The contrast enhancement of soft tissue was possible using all contrast medium injection parameters. An adequate contrast medium injection parameter for facilitating effective CE-CBCT was a 5-mL injection before exposure combined with a continuous 5-mL injection during scanning. Artificial soft tissue lesions were successfully created in the animals. The CE-CBCT images demonstrated adequate opacification of the soft tissues and vascular structures. Despite limited soft tissue resolution, the opacification of vascular structures was observed and artificial soft tissue lesions were visualized with sufficient contrast to the surrounding structures. The vascular structures and soft tissue lesions appeared well delineated in the CE-CBCT images, which was probably due to the superior spatial resolution of CE-CBCT compared to other techniques, such as multislice computed tomography.

  20. Performance evaluation of a differential phase-contrast cone-beam (DPC-CBCT) system for soft tissue imaging

    Science.gov (United States)

    Yu, Yang; Ning, Ruola; Cai, Weixing

    2011-03-01

    Differential phase-contrast (DPC) technique is promising as the next breakthrough in the field of X-ray CT imaging. Utilizing the long ignored X-ray phase information, Differential phase-contrast (DPC) technique has the potential of providing us with projection images with higher contrast in a CT scan without increasing the X-ray dose. While traditional absorption-based X-ray imaging is not very efficient at differentiating soft tissues, differential phase-contrast (DPC) is promising as a new method to boast the quality of the CT reconstruction images in term of contrast noise ratio (CNR) in soft tissue imaging. In order to validate and investigate the use of DPC technique in cone-beam CT imaging scheme, a new bench-top micro-focus DPC-based cone-beam computed tomography DPC-CBCT system has been designed and constructed in our lab for soft tissue imaging. The DPC-CBCT system consists of a micro-focus X-ray tube (focal spot 8 μm), a high-resolution detector, a rotating phantom holder and two gratings, i.e. a phase grating and an analysis. The detector system has a phosphor screen, an optical fiber coupling unit and a CMOS chip with an effective pixel pitch of 22.5 microns. The optical elements are aligned to minimize unexpected moiré patterns, and system parameters, including tube voltage (or equivalently X-ray spectrum), distances between gratings, source-to-object distance and object-to-detector distance are chosen as practicable to be applied in a rotating system. The system is tested with two simple phantoms for performance evaluation. 3-D volumetric phase-coefficients are reconstructed. The performance of the system is compared with conventional absorption-based CT in term of contrast noise ratio (CNR) under the condition of equal X-ray dose level.

  1. Linac-integrated 4D cone beam CT: first experimental results

    Science.gov (United States)

    Dietrich, Lars; Jetter, Siri; Tücking, Thomas; Nill, Simeon; Oelfke, Uwe

    2006-06-01

    A new online imaging approach, linac-integrated cone beam CT (CBCT), has been developed over the past few years. It has the advantage that a patient can be examined in their treatment position directly before or during a radiotherapy treatment. Unfortunately, respiratory organ motion, one of the largest intrafractional organ motions, often leads to artefacts in the reconstructed 3D images. One way to take this into account is to register the breathing phase during image acquisition for a phase-correlated image reconstruction. Therefore, the main focus of this work is to present a system which has the potential to investigate the correlation between internal (movement of the diaphragm) and external (data of a respiratory gating system) information about breathing phase and amplitude using an inline CBCT scanner. This also includes a feasibility study about using the acquired information for a respiratory-correlated 4D CBCT reconstruction. First, a moving lung phantom was used to develop and to specify the required methods which are based on an image reconstruction using only projections belonging to a certain moving phase. For that purpose, the corresponding phase has to be detected for each projection. In the case of the phantom, an electrical signal allows one to track the movement in real time. The number of projections available for the image reconstruction depends on the breathing phase and the size of the position range from which projections should be used for the reconstruction. The narrower this range is, the better the inner structures can be located, but also the noise of the images increases due to the limited number of projections. This correlation has also been analysed. In a second step, the methods were clinically applied using data sets of patients with lung tumours. In this case, the breathing phase was detected by an external gating system (AZ-733V, Anzai Medical Co.) based on a pressure sensor attached to the patient's abdominal region with a

  2. A model-based scatter artifacts correction for cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Wei; Zhu, Jun; Wang, Luyao [Department of Biomedical Engineering, Huazhong University of Science and Technology, Hubei 430074 (China); Vernekohl, Don; Xing, Lei, E-mail: lei@stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States)

    2016-04-15

    Purpose: Due to the increased axial coverage of multislice computed tomography (CT) and the introduction of flat detectors, the size of x-ray illumination fields has grown dramatically, causing an increase in scatter radiation. For CT imaging, scatter is a significant issue that introduces shading artifact, streaks, as well as reduced contrast and Hounsfield Units (HU) accuracy. The purpose of this work is to provide a fast and accurate scatter artifacts correction algorithm for cone beam CT (CBCT) imaging. Methods: The method starts with an estimation of coarse scatter profiles for a set of CBCT data in either image domain or projection domain. A denoising algorithm designed specifically for Poisson signals is then applied to derive the final scatter distribution. Qualitative and quantitative evaluations using thorax and abdomen phantoms with Monte Carlo (MC) simulations, experimental Catphan phantom data, and in vivo human data acquired for a clinical image guided radiation therapy were performed. Scatter correction in both projection domain and image domain was conducted and the influences of segmentation method, mismatched attenuation coefficients, and spectrum model as well as parameter selection were also investigated. Results: Results show that the proposed algorithm can significantly reduce scatter artifacts and recover the correct HU in either projection domain or image domain. For the MC thorax phantom study, four-components segmentation yields the best results, while the results of three-components segmentation are still acceptable. The parameters (iteration number K and weight β) affect the accuracy of the scatter correction and the results get improved as K and β increase. It was found that variations in attenuation coefficient accuracies only slightly impact the performance of the proposed processing. For the Catphan phantom data, the mean value over all pixels in the residual image is reduced from −21.8 to −0.2 HU and 0.7 HU for projection

  3. SimDoseCT: dose reporting software based on Monte Carlo simulation for a 320 detector-row cone-beam CT scanner and ICRP computational adult phantoms

    Science.gov (United States)

    Cros, Maria; Joemai, Raoul M. S.; Geleijns, Jacob; Molina, Diego; Salvadó, Marçal

    2017-08-01

    This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses and effective doses in ICRP anthropomorphic adult reference computational phantoms for acquisitions with the Aquilion ONE CT scanner (Toshiba). MC simulation was validated by comparing CTDI measurements within standard CT dose phantoms with results from simulation under the same conditions. SimDoseCT consists of a graphical user interface connected to a MySQL database, which contains the look-up-tables that were generated with MC simulations for volumetric acquisitions at different scan positions along the phantom using any tube voltage, bow tie filter, focal spot and nine different beam widths. Two different methods were developed to estimate organ doses and effective doses from acquisitions using other available beam widths in the scanner. A correction factor was used to estimate doses in helical acquisitions. Hence, the user can select any available protocol in the Aquilion ONE scanner for a standard adult male or female and obtain the dose results through the software interface. Agreement within 9% between CTDI measurements and simulations allowed the validation of the MC program. Additionally, the algorithm for dose reporting in SimDoseCT was validated by comparing dose results from this tool with those obtained from MC simulations for three volumetric acquisitions (head, thorax and abdomen). The comparison was repeated using eight different collimations and also for another collimation in a helical abdomen examination. The results showed differences of 0.1 mSv or less for absolute dose in most organs and also in the effective dose calculation. The software provides a suitable tool for dose assessment in standard adult patients undergoing CT

  4. Low-dose megavoltage cone-beam CT imaging using thick, segmented scintillators

    Science.gov (United States)

    El-Mohri, Youcef; Antonuk, Larry E.; Zhao, Qihua; Choroszucha, Richard B.; Jiang, Hao; Liu, Langechuan

    2011-03-01

    Megavoltage, cone-beam computed tomography (MV CBCT) employing an electronic portal imaging device (EPID) is a highly promising technique for providing soft-tissue visualization in image-guided radiotherapy. However, current EPIDs based on active matrix flat-panel imagers (AMFPIs), which are regarded as the gold standard for portal imaging and referred to as conventional MV AMFPIs, require high radiation doses to achieve this goal due to poor x-ray detection efficiency (~2% at 6 MV). To overcome this limitation, the incorporation of thick, segmented, crystalline scintillators, as a replacement for the phosphor screens used in these AMFPIs, has been shown to significantly improve the detective quantum efficiency (DQE) performance, leading to improved image quality for projection imaging at low dose. Toward the realization of practical AMFPIs capable of low dose, soft-tissue visualization using MV CBCT imaging, two prototype AMFPIs incorporating segmented scintillators with ~11 mm thick CsI:Tl and Bi4Ge3O12 (BGO) crystals were evaluated. Each scintillator consists of 120 × 60 crystalline elements separated by reflective septal walls, with an element-to-element pitch of 1.016 mm. The prototypes were evaluated using a bench-top CBCT system, allowing the acquisition of 180 projection, 360° tomographic scans with a 6 MV radiotherapy photon beam. Reconstructed images of a spatial resolution phantom, as well as of a water-equivalent phantom, embedded with tissue equivalent objects having electron densities (relative to water) varying from ~0.28 to ~1.70, were obtained down to one beam pulse per projection image, corresponding to a scan dose of ~4 cGy--a dose similar to that required for a single portal image obtained from a conventional MV AMFPI. By virtue of their significantly improved DQE, the prototypes provided low contrast visualization, allowing clear delineation of an object with an electron density difference of ~2.76%. Results of contrast, noise and contrast

  5. A statistical approach to motion compensated cone-beam

    DEFF Research Database (Denmark)

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

    number of projections to be adequate. Since the patients are breathing freely during a scan, the number of projections with similar respiration may be to low. In the following we use an iterative reconstruction combined with the simultaneous estimation of the motion field, to improve reconstruction...... in these situations. Using a simulated dataset we demonstrate that this combination outperforms the FDK but due to ill possessedness of the motion estimation it is only on par with the sole iterative method....

  6. A Statistical Approach to Motion Compensated Cone Beam Reconstruction

    DEFF Research Database (Denmark)

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

    2010-01-01

    number of projections to be adequate. Since the patients are breathing freely during a scan, the number of projections with similar respiration may be to low. In the following we use an iterative reconstruction combined with the simultaneous estimation of the motion field, to improve reconstruction...... in these situations. Using a simulated dataset we demonstrate that this combination outperforms the FDK but due to ill possessedness of the motion estimation it is only on par with the sole iterative method....

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

    Science.gov (United States)

    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

  8. 3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Roza, Marcello R; Silva, Luiz Antonio F; Barriviera, Mauricio; Januario, Alessandro L; Bezerra, Ana Cristina B; Fioravanti, Maria Clorinda S

    2011-12-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Pishipati Vinayak Kalyan Chakravarthy

    2012-01-01

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

  11. 3D Multislice and Cone-beam Computed Tomography Systems for Dental Identification

    Directory of Open Access Journals (Sweden)

    Hana Eliášová

    2017-03-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Francesc Abella

    2015-11-01

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

  13. Cone-beam tomography assessment of condylar position discrepancy between centric relation and maximal intercuspation

    Directory of Open Access Journals (Sweden)

    João César Guimarães Henriques

    2012-02-01

    Full Text Available The magnitude of occasional discrepancies between the centric relation and maximal intercuspation positions remains a controversial subject. This study quantitatively evaluated the possible discrepancies in the condyle/mandibular fossa relationship between these positions using cone-beam computed tomography. Twenty young and asymptomatic volunteers were distributed equally into normal occlusion and Angle Class I, II and III malocclusion groups. They were submitted to one tomographic scan in maximal intercuspation and one in centric relation. Measurements were performed on lateral and frontal cuts of the patients' temporomandibular joints, and the data collected were compared using Student's t test at a significance level of 5%. The results showed that there were no statistically significant differences between the centric relation and maximal intercuspation positions in young and asymptomatic patients with practically intact dentitions using cone-beam computed tomography.

  14. Diagnosis and planning in apical surgery: use of cone-beam tomography

    OpenAIRE

    Regina Karla de Pontes Lima; Norberto Batista de Faria Júnior; Juliane Maria Guerreiro Tanomaru; Mário Tanomaru Filho

    2010-01-01

    Introduction and objective: The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT) was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT) and radiography. Moreover, its clinical applications in apical surgery are discussed. Literature review and conclusion: Unli...

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

    Directory of Open Access Journals (Sweden)

    Tahra Mohammad Al-Habboubi

    2016-01-01

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

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

    LENUS (Irish Health Repository)

    Chong, Irene

    2011-11-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-15

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

  18. Investigation of impacted supernumerary teeth: a cone beam computed tomograph (cbct) study

    OpenAIRE

    Gurler, Gokhan; Delilbasi, Cagri; Delilbasi, Evren

    2017-01-01

    Purpose: The purpose of this study was to investigate the impacted supernumerary teeth which were initially detected on panoramic radiographs by using cone beam computed tomography (CBCT). Materials and Methods: In this retrospective study, supernumerary teeth diagnosed on panoramic radiographs taken from patients who had admitted for routine dental treatment were evaluated using CBCT. Patients’ age, gender, systemic conditions as well as number of supernumerary teeth, unilateral-bilateral...

  19. Geometrical Calibration and Filter Optimization for Cone-Beam Computed Tomography

    OpenAIRE

    Muders, Jens

    2015-01-01

    This thesis will discuss the requirements of a software library for tomography and will derive a framework which can be used to realize various applications in cone-beam computed tomography (CBCT). The presented framework is self-contained and is realized using the MATLAB environment in combination with native low-level technologies (C/C++ and CUDA) to improve its computational performance, while providing accessibility and extendability through to use of a scripting language environment. On ...

  20. Clinical Application of Cone Beam Computed Tomography of the Rabbit Head: Part 2-Dental Disease.

    OpenAIRE

    Riggs, G. G.; Cissell, Derek D.; Arzi, Boaz; Hatcher, David C.; Kass, Philip H; Zhen, Amy; Verstraete, Frank J. M.

    2017-01-01

    Domestic rabbits are increasing in popularity as household pets; therefore, veterinarians need to be familiar with the most common diseases afflicting rabbits including dental disease. Current diagnostic approaches include gross oral examination, endoscopic oral examination, skull radiography, and computed tomography (CT). Cone beam computed tomography (CBCT), a new oral and maxillofacial imaging modality that has the capability to produce high-resolution images, has not yet been described fo...

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

    Science.gov (United States)

    2015-10-01

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

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

    Science.gov (United States)

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

    2017-08-01

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

  3. Development and validation of two phantoms for quality control in cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-15

    The cone beam computed tomography (CBCT) was introduced into the market in the late 90 s and being a relatively new technology, also no well-established quality control protocols. There are currently projects to standardize the use of CBCT. The SEDENTEXCT project was created with the goal of developing guidelines for CBCT, including the development of a phantom for quality control it is proposed. This study aimed at the development and validation of the models of phantom: CQ{sub I}FBA{sub 0}1 e CQ{sub I}FBA{sub 0}2, the first filled with water and the second fully with solid structure in PMMA. Both models allow, otherwise the European phantom - SEDENTEXCT, its use in various models of CBCT, independent of the size of the field of view. The two phantoms used to evaluate seven parameters of quality control are: intensity or average value of pixels of five different plastics, signal to noise ratio, resolution, low contrast, spatial resolution, the accuracy of distances on the z axis, the geometric distortion and image uniformity. The spatial resolution is a critical parameter that differs significantly from the other types of scan, and in these two phantom can be evaluated by two different methods: MTF obtained by Fourier transformation of the function LSF (line spread function) and/or by analysis visual image to a pattern of bars up to 16 pl/cm. Validation was performed in three models CBCT: Kodak 9000, i-CAT Classical and Orthophos XG 3-dimensional. All imaging protocols were characterized dosimetric ally with solid state sensors to correlate with the perfect operation. These models were selected by different manufacturers have different characteristics as FOV, maximum voltage, slice thickness and patient positioning mode. The two of phantom models were viable and also showed compliance with the specifications and data available in the literature. We conclude the feasibility of the two phantom models, and model option will be linked to the practicality positioning

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

    Science.gov (United States)

    Li, Ruijiang; Han, Bin; Meng, Bowen; Maxim, Peter G.; Xing, Lei; Koong, Albert C.; Diehn, Maximilian; Loo, Billy W.

    2013-01-01

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

  5. Accelerated fast iterative shrinkage thresholding algorithms for sparsity-regularized cone-beam CT image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qiaofeng; Sawatzky, Alex; Anastasio, Mark A., E-mail: anastasio@wustl.edu [Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States); Yang, Deshan [Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri 63110 (United States); Tan, Jun [Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390 (United States)

    2016-04-15

    Purpose: The development of iterative image reconstruction algorithms for cone-beam computed tomography (CBCT) remains an active and important research area. Even with hardware acceleration, the overwhelming majority of the available 3D iterative algorithms that implement nonsmooth regularizers remain computationally burdensome and have not been translated for routine use in time-sensitive applications such as image-guided radiation therapy (IGRT). In this work, two variants of the fast iterative shrinkage thresholding algorithm (FISTA) are proposed and investigated for accelerated iterative image reconstruction in CBCT. Methods: Algorithm acceleration was achieved by replacing the original gradient-descent step in the FISTAs by a subproblem that is solved by use of the ordered subset simultaneous algebraic reconstruction technique (OS-SART). Due to the preconditioning matrix adopted in the OS-SART method, two new weighted proximal problems were introduced and corresponding fast gradient projection-type algorithms were developed for solving them. We also provided efficient numerical implementations of the proposed algorithms that exploit the massive data parallelism of multiple graphics processing units. Results: The improved rates of convergence of the proposed algorithms were quantified in computer-simulation studies and by use of clinical projection data corresponding to an IGRT study. The accelerated FISTAs were shown to possess dramatically improved convergence properties as compared to the standard FISTAs. For example, the number of iterations to achieve a specified reconstruction error could be reduced by an order of magnitude. Volumetric images reconstructed from clinical data were produced in under 4 min. Conclusions: The FISTA achieves a quadratic convergence rate and can therefore potentially reduce the number of iterations required to produce an image of a specified image quality as compared to first-order methods. We have proposed and investigated

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

    Science.gov (United States)

    Moseley, Douglas J; White, Elizabeth A; Wiltshire, Kirsty L; Rosewall, Tara; Sharpe, Michael B; Siewerdsen, Jeffrey H; Bissonnette, Jean-Pierre; Gospodarowicz, Mary; Warde, Padraig; Catton, Charles N; Jaffray, David A

    2007-03-01

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

  7. Multiresolution iterative reconstruction in high-resolution extremity cone-beam CT

    Science.gov (United States)

    Cao, Qian; Zbijewski, Wojciech; Sisniega, Alejandro; Yorkston, John; Siewerdsen, Jeffrey H.; Webster Stayman, J.

    2016-10-01

    Application of model-based iterative reconstruction (MBIR) to high resolution cone-beam CT (CBCT) is computationally challenging because of the very fine discretization (voxel size  reconstructed volume. Moreover, standard MBIR techniques require that the complete transaxial support for the acquired projections is reconstructed, thus precluding acceleration by restricting the reconstruction to a region-of-interest. To reduce the computational burden of high resolution MBIR, we propose a multiresolution penalized-weighted least squares (PWLS) algorithm, where the volume is parameterized as a union of fine and coarse voxel grids as well as selective binning of detector pixels. We introduce a penalty function designed to regularize across the boundaries between the two grids. The algorithm was evaluated in simulation studies emulating an extremity CBCT system and in a physical study on a test-bench. Artifacts arising from the mismatched discretization of the fine and coarse sub-volumes were investigated. The fine grid region was parameterized using 0.15 mm voxels and the voxel size in the coarse grid region was varied by changing a downsampling factor. No significant artifacts were found in either of the regions for downsampling factors of up to 4×. For a typical extremities CBCT volume size, this downsampling corresponds to an acceleration of the reconstruction that is more than five times faster than a brute force solution that applies fine voxel parameterization to the entire volume. For certain configurations of the coarse and fine grid regions, in particular when the boundary between the regions does not cross high attenuation gradients, downsampling factors as high as 10×  can be used without introducing artifacts, yielding a ~50×  speedup in PWLS. The proposed multiresolution algorithm significantly reduces the computational burden of high resolution iterative CBCT reconstruction and can be extended to other applications of MBIR where

  8. High-fidelity artifact correction for cone-beam CT imaging of the brain

    Science.gov (United States)

    Sisniega, A.; Zbijewski, W.; Xu, J.; Dang, H.; Stayman, J. W.; Yorkston, J.; Aygun, N.; Koliatsos, V.; Siewerdsen, J. H.

    2015-02-01

    CT is the frontline imaging modality for diagnosis of acute traumatic brain injury (TBI), involving the detection of fresh blood in the brain (contrast of 30-50 HU, detail size down to 1 mm) in a non-contrast-enhanced exam. A dedicated point-of-care imaging system based on cone-beam CT (CBCT) could benefit early detection of TBI and improve direction to appropriate therapy. However, flat-panel detector (FPD) CBCT is challenged by artifacts that degrade contrast resolution and limit application in soft-tissue imaging. We present and evaluate a fairly comprehensive framework for artifact correction to enable soft-tissue brain imaging with FPD CBCT. The framework includes a fast Monte Carlo (MC)-based scatter estimation method complemented by corrections for detector lag, veiling glare, and beam hardening. The fast MC scatter estimation combines GPU acceleration, variance reduction, and simulation with a low number of photon histories and reduced number of projection angles (sparse MC) augmented by kernel de-noising to yield a runtime of ~4 min per scan. Scatter correction is combined with two-pass beam hardening correction. Detector lag correction is based on temporal deconvolution of the measured lag response function. The effects of detector veiling glare are reduced by deconvolution of the glare response function representing the long range tails of the detector point-spread function. The performance of the correction framework is quantified in experiments using a realistic head phantom on a testbench for FPD CBCT. Uncorrected reconstructions were non-diagnostic for soft-tissue imaging tasks in the brain. After processing with the artifact correction framework, image uniformity was substantially improved, and artifacts were reduced to a level that enabled visualization of ~3 mm simulated bleeds throughout the brain. Non-uniformity (cupping) was reduced by a factor of 5, and contrast of simulated bleeds was improved from ~7 to 49.7 HU, in good agreement

  9. Cascaded systems analysis of noise and detectability in dual-energy cone-beam CT.

    Science.gov (United States)

    Gang, Grace J; Zbijewski, Wojciech; Webster Stayman, J; Siewerdsen, Jeffrey H

    2012-08-01

    Dual-energy computed tomography and dual-energy cone-beam computed tomography (DE-CBCT) are promising modalities for applications ranging from vascular to breast, renal, hepatic, and musculoskeletal imaging. Accordingly, the optimization of imaging techniques for such applications would benefit significantly from a general theoretical description of image quality that properly incorporates factors of acquisition, reconstruction, and tissue decomposition in DE tomography. This work reports a cascaded systems analysis model that includes the Poisson statistics of x rays (quantum noise), detector model (flat-panel detectors), anatomical background, image reconstruction (filtered backprojection), DE decomposition (weighted subtraction), and simple observer models to yield a task-based framework for DE technique optimization. The theoretical framework extends previous modeling of DE projection radiography and CBCT. Signal and noise transfer characteristics are propagated through physical and mathematical stages of image formation and reconstruction. Dual-energy decomposition was modeled according to weighted subtraction of low- and high-energy images to yield the 3D DE noise-power spectrum (NPS) and noise-equivalent quanta (NEQ), which, in combination with observer models and the imaging task, yields the dual-energy detectability index (d(')). Model calculations were validated with NPS and NEQ measurements from an experimental imaging bench simulating the geometry of a dedicated musculoskeletal extremities scanner. Imaging techniques, including kVp pair and dose allocation, were optimized using d(') as an objective function for three example imaging tasks: (1) kidney stone discrimination; (2) iodine vs bone in a uniform, soft-tissue background; and (3) soft tissue tumor detection on power-law anatomical background. Theoretical calculations of DE NPS and NEQ demonstrated good agreement with experimental measurements over a broad range of imaging conditions. Optimization

  10. A Simple Scatter Reduction Method in Cone-Beam Computed Tomography for Dental and Maxillofacial Applications Based on Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    Chalinee Thanasupsombat

    2018-01-01

    Full Text Available The quality of images obtained from cone-beam computed tomography (CBCT is important in diagnosis and treatment planning for dental and maxillofacial applications. However, X-ray scattering inside a human head is one of the main factors that cause a drop in image quality, especially in the CBCT system with a wide-angle cone-beam X-ray source and a large area detector. In this study, the X-ray scattering distribution within a standard head phantom was estimated using the Monte Carlo method based on Geant4. Due to small variation of low-frequency scattering signals, the scattering signals from the head phantom can be represented as the simple predetermined scattering signals from a patient’s head and subtracted the projection data for scatter reduction. The results showed higher contrast and less cupping artifacts on the reconstructed images of the head phantom and real patients. Furthermore, the same simulated scattering signals can also be applied to process with higher-resolution projection data.

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

    Directory of Open Access Journals (Sweden)

    Herdiyati Y

    2013-06-01

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

  12. Four-dimensional cone beam CT reconstruction and enhancement using a temporal nonlocal means method

    Energy Technology Data Exchange (ETDEWEB)

    Jia Xun; Tian Zhen; Lou Yifei; Sonke, Jan-Jakob; Jiang, Steve B. [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30318 (United States); Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037 (United States)

    2012-09-15

    Purpose: Four-dimensional cone beam computed tomography (4D-CBCT) has been developed to provide respiratory phase-resolved volumetric imaging in image guided radiation therapy. Conventionally, it is reconstructed by first sorting the x-ray projections into multiple respiratory phase bins according to a breathing signal extracted either from the projection images or some external surrogates, and then reconstructing a 3D CBCT image in each phase bin independently using FDK algorithm. This method requires adequate number of projections for each phase, which can be achieved using a low gantry rotation or multiple gantry rotations. Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. 4D-CBCT images at different breathing phases share a lot of redundant information, because they represent the same anatomy captured at slightly different temporal points. Taking this redundancy along the temporal dimension into account can in principle facilitate the reconstruction in the situation of inadequate number of projection images. In this work, the authors propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. Methods: The authors define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A forward-backward splitting algorithm and a Gauss-Jacobi iteration method are employed to solve the problems. The algorithms implementation on

  13. Low-dose 4D cone-beam CT via joint spatiotemporal regularization of tensor framelet and nonlocal total variation

    Science.gov (United States)

    Han, Hao; Gao, Hao; Xing, Lei

    2017-08-01

    Excessive radiation exposure is still a major concern in 4D cone-beam computed tomography (4D-CBCT) due to its prolonged scanning duration. Radiation dose can be effectively reduced by either under-sampling the x-ray projections or reducing the x-ray flux. However, 4D-CBCT reconstruction under such low-dose protocols is prone to image artifacts and noise. In this work, we propose a novel joint regularization-based iterative reconstruction method for low-dose 4D-CBCT. To tackle the under-sampling problem, we employ spatiotemporal tensor framelet (STF) regularization to take advantage of the spatiotemporal coherence of the patient anatomy in 4D images. To simultaneously suppress the image noise caused by photon starvation, we also incorporate spatiotemporal nonlocal total variation (SNTV) regularization to make use of the nonlocal self-recursiveness of anatomical structures in the spatial and temporal domains. Under the joint STF-SNTV regularization, the proposed iterative reconstruction approach is evaluated first using two digital phantoms and then using physical experiment data in the low-dose context of both under-sampled and noisy projections. Compared with existing approaches via either STF or SNTV regularization alone, the presented hybrid approach achieves improved image quality, and is particularly effective for the reconstruction of low-dose 4D-CBCT data that are not only sparse but noisy.

  14. Assessment of vertical root fractures using three imaging modalities: cone beam CT, intraoral digital radiography and film

    Science.gov (United States)

    Kambungton, J; Janhom, A; Prapayasatok, S; Pongsiriwet, S

    2012-01-01

    Objectives The aim of this study was to assess the accuracy of cone beam CT (CBCT) in detecting vertical root fractures and to compare the accuracy with images from an intraoral sensor and from conventional intraoral film. Methods 60 extracted, single-rooted human teeth were divided equally into two groups: a control group of 30 teeth and an induced fracture group of 30 teeth. All teeth were randomly placed into sockets in six dry mandibles. Each tooth was imaged by three modalities: CBCT, intraoral digital radiography and intraoral F-speed film. Three beam angulations (an orthogonal projection and additional projections with ±20° horizontal shifts of the central ray) were used when radiographs were made using film and a digital sensor. Three oral and maxillofacial radiologists evaluated the presence of root fractures twice in each image modality using a five-point confidence rating scale. Areas under receiver operating characteristic curves (Az) were computed for each observer and modality and were tested for statistical differences using the Kruskal–Wallis test. Results There was no statistical difference in the performance of the three modalities (mean of Az values: CBCT = 0.811, film = 0.797 and sensor = 0.775; p = 0.771). Conclusions There was no significant difference between intraoral film, a high-resolution complementary metal oxide semiconductor digital imaging system and CBCT in detecting vertical root fractures in mandibular single-rooted teeth. PMID:22301636

  15. Efficient TpV minimization for circular, cone-beam computed tomography reconstruction via non-convex optimization.

    Science.gov (United States)

    Cai, Ailong; Wang, Linyuan; Yan, Bin; Li, Lei; Zhang, Hanming; Hu, Guoen

    2015-10-01

    An efficient iterative algorithm, based on recent work in non-convex optimization and generalized p-shrinkage mappings, is proposed for volume image reconstruction from circular cone-beam scans. Conventional total variation regularization makes use of L1 norm of gradient magnitude images (GMI). However, this paper utilizes a generalized penalty function, induced by p-shrinkage, of GMI which is proven to be a better measurement of its sparsity. The reconstruction model is formed using generalized total p-variation (TpV) minimization, which differs with the state of the art methods, with 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. Theoretically, the proximal mapping for penalty functions induced by p-shrinkage has an exact and closed-form expression; thus, the constrained optimization can be stably and efficiently solved by the alternating direction minimization (ADM) scheme. Each sub-problem decoupled by variable splitting is minimized by explicit and easy-to-implement formulas developed by ADM. The proposed algorithm is efficiently implemented using a graphics processing unit and is referred to as "TpV-ADM." This method is robust and accurate even for very few view reconstruction datasets. Verifications and comparisons performed using various datasets (including ideal, noisy, and real projections) illustrate that the proposed method is effective and promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Assessment of vertical root fractures using three imaging modalities: cone beam CT, intraoral digital radiography and film.

    Science.gov (United States)

    Kambungton, J; Janhom, A; Prapayasatok, S; Pongsiriwet, S

    2012-02-01

    The aim of this study was to assess the accuracy of cone beam CT (CBCT) in detecting vertical root fractures and to compare the accuracy with images from an intraoral sensor and from conventional intraoral film. 60 extracted, single-rooted human teeth were divided equally into two groups: a control group of 30 teeth and an induced fracture group of 30 teeth. All teeth were randomly placed into sockets in six dry mandibles. Each tooth was imaged by three modalities: CBCT, intraoral digital radiography and intraoral F-speed film. Three beam angulations (an orthogonal projection and additional projections with ± 20° horizontal shifts of the central ray) were used when radiographs were made using film and a digital sensor. Three oral and maxillofacial radiologists evaluated the presence of root fractures twice in each image modality using a five-point confidence rating scale. Areas under receiver operating characteristic curves (A(z)) were computed for each observer and modality and were tested for statistical differences using the Kruskal-Wallis test. There was no statistical difference in the performance of the three modalities (mean of A(z) values: CBCT = 0.811, film = 0.797 and sensor = 0.775; p = 0.771). There was no significant difference between intraoral film, a high-resolution complementary metal oxide semiconductor digital imaging system and CBCT in detecting vertical root fractures in mandibular single-rooted teeth.

  17. Correction of patient positioning errors based on in-line cone beam CTs: clinical implementation and first experiences

    Directory of Open Access Journals (Sweden)

    Häring Peter

    2006-05-01

    Full Text Available Abstract Background The purpose of the study was the clinical implementation of a kV cone beam CT (CBCT for setup correction in radiotherapy. Patients and methods For evaluation of the setup correction workflow, six tumor patients (lung cancer, sacral chordoma, head-and-neck and paraspinal tumor, and two prostate cancer patients were selected. All patients were treated with fractionated stereotactic radiotherapy, five of them with intensity modulated radiotherapy (IMRT. For patient fixation, a scotch cast body frame or a vacuum pillow, each in combination with a scotch cast head mask, were used. The imaging equipment, consisting of an x-ray tube and a flat panel imager (FPI, was attached to a Siemens linear accelerator according to the in-line approach, i.e. with the imaging beam mounted opposite to the treatment beam sharing the same isocenter. For dose delivery, the treatment beam has to traverse the FPI which is mounted in the accessory tray below the multi-leaf collimator. For each patient, a predefined number of imaging projections over a range of at least 200 degrees were acquired. The fast reconstruction of the 3D-CBCT dataset was done with an implementation of the Feldkamp-David-Kress (FDK algorithm. For the registration of the treatment planning CT with the acquired CBCT, an automatic mutual information matcher and manual matching was used. Results and discussion Bony landmarks were easily detected and the table shifts for correction of setup deviations could be automatically calculated in all cases. The image quality was sufficient for a visual comparison of the desired target point with the isocenter visible on the CBCT. Soft tissue contrast was problematic for the prostate of an obese patient, but good in the lung tumor case. The detected maximum setup deviation was 3 mm for patients fixated with the body frame, and 6 mm for patients positioned in the vacuum pillow. Using an action level of 2 mm translational error, a target point

  18. A study of incisive canal using a cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyu Tae; Hwang, Eui Hwan; Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    2004-03-15

    To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70 kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. The mean length of incisive canal was 15.87 mm {+-} 2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm {+-} 0.76 and 3.89 mm {+-} 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3 {+-} 6.96 and 117.45 {+-} 7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r 0.258). This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

  20. Quality assurance phantoms for cone beam computed tomography: a systematic literature review.

    Science.gov (United States)

    de Oliveira, Marcus V L; Wenzel, Ann; Campos, Paulo S F; Spin-Neto, Rubens

    2017-03-01

    To undertake a systematic review on quality assurance (QA) phantoms for CBCT imaging, including studies on the development and application of phantoms. The MEDLINE (PubMed) bibliographic database was searched until May 2016 for studies evaluating the development and use of phantoms in CBCT image QA. The search strategy was restricted to English language publications using the following combined terms: (Cone Beam CT) OR (Cone Beam Computed Tomography) OR (Cone-Beam Computed Tomography) OR (CBCT) AND (quality OR phantom). It was assessed which of the six image quality parameters stated by the European Commission could be evaluated with each phantom and which of them actually were. The search strategy yielded 37 studies, which had developed and used (25 studies) or only used (12 studies) a phantom in CBCT image QA. According to the literature, in 7 phantoms, it is possible to evaluate 4 or more image quality parameters while in 11 phantoms, merely 1 parameter can be evaluated. Only two phantoms permit the evaluation of the six image quality parameters stated by the European Commission. The parameters, which can most often be evaluated using a phantom, are image density values, spatial resolution and geometric accuracy. The SEDENTEXCT phantom was used most frequently. In two studies, all quality parameters suggested by the European Commission were evaluated. QA phantoms rarely allow all image quality parameters stated by the European Commission to be evaluated. Furthermore, alternative phantoms, which allow all image quality parameters to be evaluated in a single exposure, even for a small field of view, should be developed.

  1. Comparison of cone beam CT and conventional CT in absorbed and effective dose

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Yeon; Han, Jin Woo; Park, In Woo [Department of Oral and Maxillofacial Radiology, College of Dentistry, Kangnung National University and Reseach Institute of Oral Science, Gangneung (Korea, Republic of)

    2008-03-15

    This study provides comparative measurements of absorbed and effective doses for newly developed cone beam computed tomography (CT) in comparison with these doses for conventional CT. Thermoluminescent dosimeter rods (TLD rod: GR-200, Thermo Fisher Scientific Inc., Waltham, MA, USA) were placed at 25 sites throughout the layers of Male ART Head and Neck Phantom (Radiology Support Devices Inc., Long Beach, USA) for dosimetry. Implagraphy, DCT Pro (Vatech Co., Hwasung, Korea) units, SCT-6800TXL (Shimadzu Corp., Kyoto, Japan), and Cranex 3+ (Soredex Orion Corp., Helsinki, Finland) were used for radiation exposures. Absorption doses were measured with Harshaw 3500TLD reader (Thermo Fisher Scientific Inc., Waltham, MA, USA). Radiation weighted doses and effective doses were measured and calculated by 2005 ICRP tissue weighting factors. Absorbed doses in Rt. submandibular gland were 110.57 mGy for SCT 6800TXL (Implant), 24.56 mGy for SCT 6800TXL (3D), 22.39 mGy for Implagraphy3, 7.19 mGy for DCT Pro, 5.96 mGy for Implagraphy1, 0.70 mGy for Cranex 3+. Effective doses (E2005draft) were 2.551 mSv for SCT 6800TXL (Implant), 1.272 mSv for SCT 6800TXL (3D), 0.598 mSv for Implagraphy3, 0.428 mSv for DCT Pro and 0.146 mSv for Implagraphy1. These are 108.6, 54.1, 25.5, 18.2 and 6.2 times greater than panoramic examination (Cranex 3+) doses (0.023 mSv). Cone beam CT machines recently developed in Korea, showed lower effective doses than conventional CT. Cone beam CT provides a lower dose and cost motive to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology.

  2. The adaptation of megavoltage cone beam CT for use in standard radiotherapy treatment planning

    Science.gov (United States)

    Thomas, T. Hannah Mary; Devakumar, D.; Purnima, S.; Ravindran, B. Paul

    2009-04-01

    Potential areas where megavoltage computed tomography (MVCT) could be used are second- and third-phase treatment planning in 3D conformal radiotherapy and IMRT, adaptive radiation therapy, single fraction palliative treatment and for the treatment of patients with metal prostheses. A feasibility study was done on using MV cone beam CT (CBCT) images generated by proprietary 3D reconstruction software based on the FDK algorithm for megavoltage treatment planning. The reconstructed images were converted to a DICOM file set. The pixel values of megavoltage cone beam computed tomography (MV CBCT) were rescaled to those of kV CT for use with a treatment planning system. A calibration phantom was designed and developed for verification of geometric accuracy and CT number calibration. The distance measured between two marker points on the CBCT image and the physical dimension on the phantom were in good agreement. Point dose verification for a 10 cm × 10 cm beam at a gantry angle of 0° and SAD of 100 cm were performed for a 6 MV beam for both kV and MV CBCT images. The point doses were found to vary between ±6.1% of the dose calculated from the kV CT image. The isodose curves for 6 MV for both kV CT and MV CBCT images were within 2% and 3 mm distance-to-agreement. A plan with three beams was performed on MV CBCT, simulating a treatment plan for cancer of the pituitary. The distribution obtained was compared with those corresponding to that obtained using the kV CT. This study has shown that treatment planning with MV cone beam CT images is feasible.

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

    Directory of Open Access Journals (Sweden)

    Sainath Dinapadu

    2013-01-01

    Full Text Available Dens invaginatus is a developmental variation in the formation of a tooth that causes changes in the internal anatomy of the tooth. The presence of double dens invaginatus is extremely rare. Understanding the type, extension, and complex morphology of dens invaginatus is essential. Diagnosis of this condition using conventional radiographic techniques is not easy. Advanced imaging techniques, such as cone beam computed tomography (CBCT are very helpful in diagnosis of these complex anatomic variations. In the present case report, we demonstrate the use of CBCT in the evaluation and treatment planning of bilateral maxillary dens invaginatus, of which one presented as a case of double dens.

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

    OpenAIRE

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

    2014-01-01

    Adaptive Radiation Therapy (ART) was developed based on Image-guided Radiation Therapy (IGRT) and it is the trend of photon radiation therapy. To get a better use of Cone Beam CT (CBCT) images for ART, the CBCT system model was established based on Monte Carlo program and validated against the measurement. The BEAMnrc program was adopted to the KV x-ray tube. Both IOURCE-13 and ISOURCE-24 were chosen to simulate the path of beam particles. The measured Percentage Depth Dose (PDD) and lateral ...

  5. Cone beam CT evaluation of patient set-up accuracy as a QA tool

    DEFF Research Database (Denmark)

    Nielsen, Morten; Bertelsen, Anders; Westberg, Jonas

    2009-01-01

    Purpose. To quantify by means of cone beam CT the random and systematic uncertainty involved in radiotherapy, and to determine if this information can be used for e.g. technical quality assurance, evaluation of patient immobilization and determination of margins for the treatment planning. Patients...... errors have a vanishing mean and a systematic error of 0.5 1.2 degrees and a random error of 0.40.7 degrees. The uncertainties from the first three treatment sessions (disregarding rotations) lead to a margin of 4 mm from ITV to PTV for Head-and-Neck patients (all directions) and Thorax patients (AP...

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

    Science.gov (United States)

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

    2016-01-01

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

  7. Karyotype, Pedigree and cone-beam computerized tomography analysis of a case of nonsyndromic pandental anomalies.

    Science.gov (United States)

    Dharmani, Umesh; Jadhav, Ganesh Ranganath; Kaur Dharmani, Charan Kamal; Rajput, Akhil; Mittal, Priya; Abraham, Sathish; Soni, Vinay

    2015-01-01

    This case report presented a karyotype and pedigree analysis of a case with unusual combination of dental anomalies: Generalized short roots, talon cusps, dens invagination, low alveolar bone heights, very prominent cusp of carabelli and protostylid on first permanent molars, taurodontism of second permanent molars, rotated, missing and impacted teeth. None of the anomalies alone are rare. However, until date, nonsyndromic pandental anomalies that are affecting entire dentition with detailed karyotype, pedigree and cone-beam computerized tomography analysis have not been reported. The occurrence of these anomalies is probably incidental as the conditions are etiologically unrelated.

  8. Cone beam computed tomography for diagnosis and treatment planning of supernumerary teeth.

    Science.gov (United States)

    Gurgel, Carla Vecchione; Costa, Ana Lidia Soares; Kobayashi, Tatiana Yurico; Rios, Daniela; Silva, Salete Moura Bonifacio; Machado, Maria Aperecida de Andrade Moreira; Oliveira, Thais Marchini

    2012-01-01

    Conventional radiographic images are frequently used to detect supernumerary teeth. However, recent developments in 3D imaging systems have enabled dentists to better visualize supernumerary teeth, with better contrast and more details. Cone beam computed tomography (CBCT) has improved diagnosis and treatment planning of patients with supernumerary teeth. The decision to use CBCT should be based on the diagnostic information required. This article presents three case reports of patients with supernumerary teeth to demonstrate the need for accurate diagnosis and treatment planning based on a comprehensive evaluation using CBCT.

  9. Blind deconvolution combined with level set method for correcting cupping artifacts in cone beam CT

    Science.gov (United States)

    Xie, Shipeng; Zhuang, Wenqin; Li, Baosheng; Bai, Peirui; Shao, Wenze; Tong, Yubing

    2017-02-01

    To reduce cupping artifacts and enhance contrast resolution in cone-beam CT (CBCT), in this paper, we introduce a new approach which combines blind deconvolution with a level set method. The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented on a single-scan acquisition. The results demonstrate that the algorithm is practical and effective for reducing the cupping artifacts and enhance contrast resolution on the images, preserves the quality of the reconstructed image, and is very robust.

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

    Directory of Open Access Journals (Sweden)

    Heckel Frank

    2016-09-01

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

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

    OpenAIRE

    Roque-Torres, Gina D; Meneses-López, Abraham; Norberto Bóscolo, Frab; De Almeida, Solange María; Haiter Neto, Francisco

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  13. Karyotype, Pedigree and cone-beam computerized tomography analysis of a case of nonsyndromic pandental anomalies

    Science.gov (United States)

    Dharmani, Umesh; Jadhav, Ganesh Ranganath; Kaur Dharmani, Charan Kamal; Rajput, Akhil; Mittal, Priya; Abraham, Sathish; Soni, Vinay

    2015-01-01

    This case report presented a karyotype and pedigree analysis of a case with unusual combination of dental anomalies: Generalized short roots, talon cusps, dens invagination, low alveolar bone heights, very prominent cusp of carabelli and protostylid on first permanent molars, taurodontism of second permanent molars, rotated, missing and impacted teeth. None of the anomalies alone are rare. However, until date, nonsyndromic pandental anomalies that are affecting entire dentition with detailed karyotype, pedigree and cone-beam computerized tomography analysis have not been reported. The occurrence of these anomalies is probably incidental as the conditions are etiologically unrelated. PMID:26283856

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

    Science.gov (United States)

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

    2016-01-01

    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

  15. Cone-beam reconstruction for the two-circles-plus-one-line trajectory.

    Science.gov (United States)

    Lu, Yanbin; Yang, Jiansheng; Emerson, John W; Mao, Heng; Zhou, Tie; Si, Yuanzheng; Jiang, Ming

    2012-05-07

    The Kodak Image Station In-Vivo FX has an x-ray module with cone-beam configuration for radiographic imaging but lacks the functionality of tomography. To introduce x-ray tomography into the system, we choose the two-circles-plus-one-line trajectory by mounting one translation motor and one rotation motor. We establish a reconstruction algorithm by applying the M-line reconstruction method. Numerical studies and preliminary physical phantom experiment demonstrate the feasibility of the proposed design and reconstruction algorithm.

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

    Science.gov (United States)

    Cohenca, Nestor; Shemesh, Hagay

    2015-09-01

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

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

    DEFF Research Database (Denmark)

    Sansare, K; Singh, D; Sontakke, S

    2014-01-01

    Aim: A clinical study was done to assess the clinical diagnostic accuracy of cone beam computed tomography (CBCT) in detecting proximal cavitated carious lesions in order to determine whether cavitation should be reported when a CBCT examination is available. Materials and Methods: 79 adjacent...... proximal surfaces without restorations in permanent teeth were examined. Patients suspected to have carious lesions after a visual clinical and a bitewing examination participated in a CBCT examination (Kodak 9000 3D, 5 × 3.7 cm field of view, voxel size 0.07 mm). Ethical approval and informed consent were...... higher for CBCT than for bitewings (average difference 33%, p proximal surfaces...

  18. Physical performance and image optimization of megavoltage cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Morin, Olivier; Aubry, Jean-Francois; Aubin, Michele; Chen, Josephine; Descovich, Martina; Hashemi, Ali-Bani; Pouliot, Jean [Department of Radiation Oncology, Helen Diller Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 and UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California 94158 (United States); Department of Radiation Oncology, Helen Diller Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 (United States); Siemens Oncology Care Systems, Concord, California 94520 (United States); Department of Radiation Oncology, Helen Diller Comprehensive Cancer Center, University of California San Francisco, San Francisco, California 94143 and UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California 94158 (United States)

    2009-04-15

    Megavoltage cone-beam CT (MVCBCT) is the most recent addition to the in-room CT systems developed for image-guided radiation therapy. The first generation MVCBCT system consists of a 6 MV treatment x-ray beam produced by a conventional linear accelerator equipped with a flat panel amorphous silicon detector. The objective of this study was to evaluate the physical performance of MVCBCT in order to optimize the system acquisition and reconstruction parameters for image quality. MVCBCT acquisitions were performed with the clinical system but images were reconstructed and analyzed with a separate research workstation. The geometrical stability and the positioning accuracy of the system were evaluated by comparing geometrical calibrations routinely performed over a period of 12 months. The beam output and detector intensity stability during MVCBCT acquisition were also evaluated by analyzing in-air acquisitions acquired at different exposure levels. Several system parameters were varied to quantify their impact on image quality including the exposure (2.7, 4.5, 9.0, 18.0, and 54.0 MU), the craniocaudal imaging length (2, 5, 15, and 27.4 cm), the voxel size (0.5, 1, and 2 mm), the slice thickness (1, 3, and 5 mm), and the phantom size. For the reconstruction algorithm, the study investigated the effect of binning, averaging and diffusion filtering of raw projections as well as three different projection filters. A head-sized water cylinder was used to measure and improve the uniformity of MVCBCT images. Inserts of different electron densities were placed in a water cylinder to measure the contrast-to-noise ratio (CNR). The spatial resolution was obtained by measuring the point-spread function of the system using an iterative edge blurring technique. Our results showed that the geometric stability and accuracy of MVCBCT were better than 1 mm over a period of 12 months. Beam intensity variations per projection of up to 35.4% were observed for a 2.7 MU MVCBCT acquisition

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

    Directory of Open Access Journals (Sweden)

    Ashok Balasundaram

    2012-01-01

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

  20. Four-dimensional Cone Beam CT Reconstruction and Enhancement using a Temporal Non-Local Means Method

    CERN Document Server

    Jia, Xun; Lou, Yifei; Sonke, Jan-Jakob; Jiang, Steve B

    2012-01-01

    Four-dimensional Cone Beam Computed Tomography (4D-CBCT) has been developed to provide respiratory phase resolved volumetric imaging in image guided radiation therapy (IGRT). Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. In this work, we propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. We define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A...

  1. 3D Nondestructive Visualization and Evaluation of TRISO Particles Distribution in HTGR Fuel Pebbles Using Cone-Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Gongyi Yu

    2017-01-01

    Full Text Available A nonuniform distribution of tristructural isotropic (TRISO particles within a high-temperature gas-cooled reactor (HTGR pebble may lead to excessive thermal gradients and nonuniform thermal expansion during operation. If the particles are closely clustered, local hotspots may form, leading to excessive stresses on particle layers and an increased probability of particle failure. Although X-ray digital radiography (DR is currently used to evaluate the TRISO distributions in pebbles, X-ray DR projection images are two-dimensional in nature, which would potentially miss some details for 3D evaluation. This paper proposes a method of 3D visualization and evaluation of the TRISO distribution in HTGR pebbles using cone-beam computed tomography (CBCT: first, a pebble is scanned on our high-resolution CBCT, and 2D cross-sectional images are reconstructed; secondly, all cross-sectional images are restructured to form the 3D model of the pebble; then, volume rendering is applied to segment and display the TRISO particles in 3D for visualization and distribution evaluation. For method validation, several pebbles were scanned and the 3D distributions of the TRISO particles within the pebbles were produced. Experiment results show that the proposed method provides more 3D than DR, which will facilitate pebble fabrication research and production quality control.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

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

    Science.gov (United States)

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

    2015-03-01

    Cone beam computed tomography (CBCT) systems with rotational gantries that have standard flat panel detectors (FPD) are widely used for the 3D rendering of vascular structures using Feldkamp cone beam reconstruction algorithms. One of the inherent limitations of these systems is limited resolution (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.

  4. Cone Beam Computed Tomography Assessment of Accessory Infraorbital Foramen and Determination of Infraorbital Foramen Position.

    Science.gov (United States)

    Ali, Ibrahim K; Sansare, Kaustubh; Karjodkar, Freny R; Salve, Prashant

    2017-11-09

    There is no evidence about evaluating accessory infraorbital foramen by 3-dimensional analysis like multi slice computed tomography or cone beam computed tomography (CBCT) in human subjects. To authors' best knowledge this is a first study to assess the accessory infraorbital foramen and position of infraorbital foramen in relation to crown of maxillary teeth using CBCT. This study primarily aimed to assess the location and number of accessory infraorbital foramen (AIOF), to measure the distance between main infraorbital foramen and AIOF and secondarily to determine the position of infraorbital foramen in relation to crowns of maxillary second premolar, first molar, and second molar. Cone beam computed tomography volumes of 200 patients were retrieved from the digital imaging and communications in medicine archive folder. Accessory infraorbital foramen was recognized in 29% of the patients among whom 46.6% were present on the right side, 31% on the left side, and 22.4% located bilaterally. The most frequent position of infraorbital foramen was found to be in line with crown of second premolar. The presence of AIOF and inability to recognize it in preoperative evaluation could be considered among the other reasons of failure or incomplete anesthesia.

  5. Cone-Beam Computed Tomography: A New Method for Imaging of the Temporal Bone

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

    Background: Clinical cone-beam computed tomography (CBCT), used in diagnostics of dental and maxillofacial radiology for almost 10 years, allows three-dimensional (3D) imaging of a focused area, with reasonable radiation dose. Purpose: To clarify the applicability of CBCT in imaging of the temporal bone. Material and Methods: We imaged cadaver temporal bones, one non-operated and five postmortem operated, with CBCT to evaluate the accuracy of this method in showing clinically important landmarks and the positions of middle-ear implants. In addition, to clarify the imaging protocols for the best possible result, we conducted a contrast-to-noise ratio (CNR) analysis by imaging a specially built phantom insert with different protocols. Results: For all the temporal bones, image quality was good and of diagnostic value, and the surgical landmarks as well as positions and details of the implants could be accurately observed. Based on measurements conducted with the phantom, the best possible clarity of the images with the machine used (3D Accuitomo; Morita Co., Kyoto (Japan)) was achieved with a tube voltage of 80 kVp and a current of 4 mA. Conclusion: Cone-beam CT is a promising new method for otologic imaging, based on its accuracy and relatively low radiation exposure per investigation

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

    Science.gov (United States)

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

    2016-07-21

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-07

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-15

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

  9. Diagnostic accuracy of Cone Beam Computed Tomography, conventional and digital radiographs in detecting interproximal caries.

    Science.gov (United States)

    Safi, Y; Shamloo Mahmoudi, N; Aghdasi, M M; Eslami Manouchehri, M; Rahimian, R; Valizadeh, S; Vasegh, Z; Azizi, Z

    2015-01-01

    Presently, various imaging methods are available for the disclosure of proximal caries. Some recent studies have attempted to determine the diagnostic accuracy of available modalities, but they have shown variable results. Aim: This study was carried out to recognize and examine the correctness of cone-beam computed tomography (CBCT), regular radiographs and the nondirect digital system in the disclosure of interproximal caries. Materials and Method: In this observational tryout study, forty-two extracted non-cavitated, unrestored person molar and premolar teeth were placed in the blocks with proximal surfaces in touch. Then they were appraised by CBCT, formal radiographs and the nondirect digital system for the disclosure of interproximal caries. Four oral and maxillofacial radiologists used a 4-point scale to assess the pictures for the existence or absence of proximal caries. Caries depth was specified by histological examination. The gathered data were assessed by SPSS software using Weighted Kappa and Friedman test. Results: Statistics demonstrated that the accuracy of the indirect digital system was somewhat better than conventional systems. The accuracy of the indirect digital system was better than cone beam system, and this difference was statistically significant. Conclusion: The digital system was better than CBCT in the disclosure of proximal caries. The formal radiography fell in between the two other systems without a statistically significant deviation in detecting caries. Thus, CBCT is not advised to detect proximal caries because of the higher radiation dose.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2014-03-01

    The objective of this study was to assess the value of cone-beam computed tomographic (CT) images in the primary diagnosis and management of 128 outpatients with disorders of the temporomandibular joint (TMJ). Before a diagnosis was made and treatment planned, the history was taken, physical examination made, and the orthopantomogram studied. After assessment of the cone-beam CT, the oral and maxillofacial surgeon (specialist or resident) was allowed to revise the provisional primary diagnosis and management. The degree of certainty was rated by the clinician before and after the cone-beam CT had been assessed. The primary diagnosis was changed in 32 patients (25%), additional diagnostic procedures were changed in 57 (45%), and the treatment was changed in 15 (12%) (in 4 the treatment was changed to a (minimally) invasive procedure). A total of 74 patients (58%) had their diagnosis and management changed after the cone-beam CT had been assessed. Changes in diagnosis and management were clinically relevant in 9/32 and 9/61 patients, respectively. The clinician's certainty about the primary diagnosis increased after the cone-beam CT had been assessed in 57 patients. Logistic regression analysis showed that the odds in favour of changes in primary diagnosis and management increased when limited mandibular function was a primary symptom, the patient was taking medication for pain, and the articular eminence could not be assessed on OPT. Assessment of cone-beam CT led to changes in primary diagnosis and management in more than half the patients with disorders of the TMJ. Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    Energy Technology Data Exchange (ETDEWEB)

    Reitz, Bodo [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Gayou, Olivier [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Parda, David S [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Miften, Moyed [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States)

    2008-02-21

    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.

  13. Monitoring tumor motion with on-line mega-voltage cone-beam computed tomography imaging in a cine mode

    Science.gov (United States)

    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.

  14. Cone-beam CT image contrast and attenuation-map linearity improvement (CALI) for brain stereotactic radiosurgery procedures

    Science.gov (United States)

    Hashemi, Sayed Masoud; Lee, Young; Eriksson, Markus; Nordström, Hâkan; Mainprize, James; Grouza, Vladimir; Huynh, Christopher; Sahgal, Arjun; Song, William Y.; Ruschin, Mark

    2017-03-01

    A Contrast and Attenuation-map (CT-number) Linearity Improvement (CALI) framework is proposed for cone-beam CT (CBCT) images used for brain stereotactic radiosurgery (SRS). The proposed framework is used together with our high spatial resolution iterative reconstruction algorithm and is tailored for the Leksell Gamma Knife ICON (Elekta, Stockholm, Sweden). The incorporated CBCT system in ICON facilitates frameless SRS planning and treatment delivery. The ICON employs a half-cone geometry to accommodate the existing treatment couch. This geometry increases the amount of artifacts and together with other physical imperfections causes image inhomogeneity and contrast reduction. Our proposed framework includes a preprocessing step, involving a shading and beam-hardening artifact correction, and a post-processing step to correct the dome/capping artifact caused by the spatial variations in x-ray energy generated by bowtie-filter. Our shading correction algorithm relies solely on the acquired projection images (i.e. no prior information required) and utilizes filtered-back-projection (FBP) reconstructed images to generate a segmented bone and soft-tissue map. Ideal projections are estimated from the segmented images and a smoothed version of the difference between the ideal and measured projections is used in correction. The proposed beam-hardening and dome artifact corrections are segmentation free. The CALI was tested on CatPhan, as well as patient images acquired on the ICON system. The resulting clinical brain images show substantial improvements in soft contrast visibility, revealing structures such as ventricles and lesions which were otherwise un-detectable in FBP-reconstructed images. The linearity of the reconstructed attenuation-map was also improved, resulting in more accurate CT#.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-15

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

  17. Memory-efficient algorithm for stored projection and backprojection matrix in helical CT.

    Science.gov (United States)

    Guo, Minghao; Gao, Hao

    2017-04-01

    Iterative image reconstruction is often time-consuming, especially for helical CT. The calculation of X-ray projections and backprojections are computationally expensive. Although they can be significantly accelerated by parallel computing (e.g., via graphics processing unit (GPU)), they have to be calculated numerous times on-the-fly (OTF) during iterative image reconstruction due to insufficient memory storage. In this work, the memory-efficient algorithm for stored system matrix (SSM) is developed for both projections and backprojections to avoid repeated OTF computations of system matrices. The SSM algorithm is based on the shift-invariance for projection and backprojection under a rotating coordinate. As a result, the size of projection and backprojection matrices can be significantly reduced and fully stored in memory. The proposed method can be readily incorporated into iterative reconstruction algorithm with minor modification, i.e., by replacing OTF for SSM. Rigorous mathematical analysis is carried out to establish the shift-invariance for ray-driven projection and pixel-driven backprojection. Numerical results via GPU suggest that the proposed SSM method has improved computational efficiency from the OTF method, i.e., by three- to sixfold acceleration for the projection and 3- to 16-fold acceleration for the backprojection respectively for helical CT. We propose a memory-efficient SSM algorithm for projections and backprojections so that system matrices can be fully stored on the state-of-the-art GPU to facilitate the rapid iterative helical CT image reconstruction. © 2017 American Association of Physicists in Medicine.

  18. Role of cone-beam computed tomography with a large field of view in Goldenhar syndrome.

    Science.gov (United States)

    Nardi, Cosimo; De Falco, Luisa; Selvi, Valeria; Lorini, Chiara; Calistri, Linda; Colagrande, Stefano

    2018-02-01

    Goldenhar syndrome is a rare disease with hemifacial microsomia and craniofacial disorders originating from the first and second branchial arches, such as ocular, auricular, and vertebral anomalies. The complexity and variety of the ways in which the disease presents itself usually need several examinations. In this study, we aimed to evaluate both craniofacial and vertebral skeletal anomalies and asymmetries between the nonaffected and affected sides in patients with Goldenhar syndrome by using cone-beam computed tomography. Ten patients (7-14 years old; 6 boys, 4 girls) were evaluated via NewTom 5G cone-beam computed tomography (QR srl, Verona, Italy) with a large field of view (18 × 16 cm). Ten anatomic facial landmarks were identified to measure the following distances bilaterally: sella turcica (ST)-mandibular angle, ST-condyle, ST-mastoid, ST-mental foramen, ST-fronto zygomatic suture, ST-zygomatic temporal suture, ST-zygomatic facial foramen, ST-sphenopalatine fossa, mandibular angle-mandibular symphysis, and mandibular angle-condyle. The following 6 volumes were calculated bilaterally: orbit, maxillary sinus, condyle, external ear canal, middle ear, and internal auditory canal. These measurements were performed to assess skeletal asymmetries to compare the nonaffected side with the affected side by the Wilcoxon test. Cervical spine anomalies were classified into fusion anomalies and posterior arch deficiencies. All patients showed a deficit of skeletal development on the affected side. Statistically significant differences (0.001 ≤ P value ≤ 0.043) between the nonaffected and affected sides were recorded for all measurements, except for ST-frontozygomatic suture, mandibular angle-mandibular symphysis, and maxillary sinus volume. Vertebral fusion anomalies and posterior arch deficiencies were found in 7 and 4 patients, respectively. Cone-beam computed tomography with a large field of view was able to accurately identify craniofacial and vertebral

  19. Cone beam breast CT with multiplanar and three dimensional visualization in differentiating breast masses compared with mammography

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    Zhao, Binghui [Department of Radiology, Shanghai Tenth People' s Hospital, Tongji University, Shanghai 200072 (China); Zhang, Xiaohua [Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627 (United States); Cai, Weixing [Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY 14642 (United States); Conover, David [Koning Corporation, West Henrietta, NY 14586 (United States); Ning, Ruola, E-mail: ruola_ning@urmc.rochester.edu [Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY 14642 (United States)

    2015-01-15

    Objective: This pilot study was to evaluate cone beam breast computed tomography (CBBCT) with multiplanar and three dimensional (3D) visualization in differentiating breast masses in comparison with two-view mammograms. Methods: Sixty-five consecutive female patients (67 breasts) were scanned by CBBCT after conventional two-view mammography (Hologic, Motarget, compression factor 0.8). For CBBCT imaging, three hundred (1024 × 768 × 16 b) two-dimensional (2D) projection images were acquired by rotating the x-ray tube and a flat panel detector (FPD) 360 degree around one breast. Three-dimensional CBBCT images were reconstructed from the 2D projections. Visage CS 3.0 and Amira 5.2.2 were used to visualize reconstructed CBBCT images. Results: Eighty-five breast masses in this study were evaluated and categorized under the breast imaging reporting and data system (BI-RADS) according to plain CBBCT images and two-view mammograms, respectively, prior to biopsy. BI-RADS category of each breast was compared with biopsy histopathology. The results showed that CBBCT with multiplanar and 3D visualization would be helpful to identify the margin and characteristics of breast masses. The category variance ratios for CBBCT under the BI-RADS were 23.5% for malignant tumors (MTs) and 27.3% for benign lesions in comparison with pathology, which were evidently closer to the histopathology results than those of two-view mammograms, p value <0.01. With the receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) of CBBCT was 0.911, larger than that (AUC 0.827) of two-view mammograms, p value <0.01. Conclusion: CBBCT will be a distinctive noninvasive technology in differentiating and categorizing breast masses under BI-RADS. CBBCT may be considerably more effective to identify breast masses, especially some small, uncertain or multifocal masses than conventional two-view mammography.

  20. 3D printing for orthopedic applications: from high resolution cone beam CT images to life size physical models

    Science.gov (United States)

    Jackson, Amiee; Ray, Lawrence A.; Dangi, Shusil; Ben-Zikri, Yehuda K.; Linte, Cristian A.

    2017-03-01

    With increasing resolution in image acquisition, the project explores capabilities of printing toward faithfully reflecting detail and features depicted in medical images. To improve safety and efficiency of orthopedic surgery and spatial conceptualization in training and education, this project focused on generating virtual models of orthopedic anatomy from clinical quality computed tomography (CT) image datasets and manufacturing life-size physical models of the anatomy using 3D printing tools. Beginning with raw micro CT data, several image segmentation techniques including thresholding, edge recognition, and region-growing algorithms available in packages such as ITK-SNAP, MITK, or Mimics, were utilized to separate bone from surrounding soft tissue. After converting the resulting data to a standard 3D printing format, stereolithography (STL), the STL file was edited using Meshlab, Netfabb, and Meshmixer. The editing process was necessary to ensure a fully connected surface (no loose elements), positive volume with manifold geometry (geometry possible in the 3D physical world), and a single, closed shell. The resulting surface was then imported into a "slicing" software to scale and orient for printing on a Flashforge Creator Pro. In printing, relationships between orientation, print bed volume, model quality, material use and cost, and print time were considered. We generated anatomical models of the hand, elbow, knee, ankle, and foot from both low-dose high-resolution cone-beam CT images acquired using the soon to be released scanner developed by Carestream, as well as scaled models of the skeletal anatomy of the arm and leg, together with life-size models of the hand and foot.

  1. Geometric Calibration Using Line Fiducials for Cone-Beam CT with General, Non-Circular Source-Detector Trajectories.

    Science.gov (United States)

    Jacobson, M W; Ketcha, M; Uneri, A; Goerres, J; De Silva, T; Reaungamornrat, S; Vogt, S; Kleinszig, G; Siewerdsen, J H

    2017-03-01

    Traditional BB-based geometric calibration methods for cone-beam CT (CBCT) rely strongly on foreknowledge of the scan trajectory shape. This is a hindrance to the implementation of variable trajectory CBCT systems, normally requiring a dedicated calibration phantom or software algorithm for every scan orbit of interest. A more flexible method of calibration is proposed here that accommodates multiple orbit types - including strongly noncircular trajectories - with a single phantom and software routine. The proposed method uses a calibration phantom consisting of multiple line-shaped wire segments. Geometric models relating the 3D line equations of the wires to the 2D line equations of their projections are used as the basis for system geometry estimation. This method was tested using a mobile C-arm CT system and comparisons were made to standard BB-based calibrations. Simulation studies were also conducted using a sinusoid-on-sphere orbit. Calibration performance was quantified in terms of Point Spread Function (PSF) width and back projection error. Visual image quality was assessed with respect to spatial resolution in trabecular bone in an anthropomorphic head phantom. The wire-based calibration method performed equal to or better than BB-based calibrations in all evaluated metrics. For the sinusoidal scans, the method provided reliable calibration, validating its application to non-circular trajectories. Furthermore, the ability to improve image quality using non-circular orbits in conjunction with this calibration method was demonstrated. The proposed method has been shown feasible for conventional circular CBCT scans and offers a promising tool for non-circular scan orbits that can improve image quality, reduce dose, and extend field of view.

  2. 4D cone-beam CT imaging for guidance in radiation therapy: setup verification by use of implanted fiducial markers

    Science.gov (United States)

    Jin, Peng; van Wieringen, Niek; Hulshof, Maarten C. C. M.; Bel, Arjan; Alderliesten, Tanja

    2016-03-01

    The use of 4D cone-beam computed tomography (CBCT) and fiducial markers for guidance during radiation therapy of mobile tumors is challenging due to the trade-off between image quality, imaging dose, and scanning time. We aimed to investigate the visibility of markers and the feasibility of marker-based 4D registration and manual respiration-induced marker motion quantification for different CBCT acquisition settings. A dynamic thorax phantom and a patient with implanted gold markers were included. For both the phantom and patient, the peak-to-peak amplitude of marker motion in the cranial-caudal direction ranged from 5.3 to 14.0 mm, which did not affect the marker visibility and the associated marker-based registration feasibility. While using a medium field of view (FOV) and the same total imaging dose as is applied for 3D CBCT scanning in our clinic, it was feasible to attain an improved marker visibility by reducing the imaging dose per projection and increasing the number of projection images. For a small FOV with a shorter rotation arc but similar total imaging dose, streak artifacts were reduced due to using a smaller sampling angle. Additionally, the use of a small FOV allowed reducing total imaging dose and scanning time (~2.5 min) without losing the marker visibility. In conclusion, by using 4D CBCT with identical or lower imaging dose and a reduced gantry speed, it is feasible to attain sufficient marker visibility for marker-based 4D setup verification. Moreover, regardless of the settings, manual marker motion quantification can achieve a high accuracy with the error <1.2 mm.

  3. Brain perfusion imaging using a Reconstruction-of-Difference (RoD) approach for cone-beam computed tomography

    Science.gov (United States)

    Mow, M.; Zbijewski, W.; Sisniega, A.; Xu, J.; Dang, H.; Stayman, J. W.; Wang, X.; Foos, D. H.; Koliatsos, V.; Aygun, N.; Siewerdsen, J. H.

    2017-03-01

    Purpose: To improve the timely detection and treatment of intracranial hemorrhage or ischemic stroke, recent efforts include the development of cone-beam CT (CBCT) systems for perfusion imaging and new approaches to estimate perfusion parameters despite slow rotation speeds compared to multi-detector CT (MDCT) systems. This work describes development of a brain perfusion CBCT method using a reconstruction of difference (RoD) approach to enable perfusion imaging on a newly developed CBCT head scanner prototype. Methods: A new reconstruction approach using RoD with a penalized-likelihood framework was developed to image the temporal dynamics of vascular enhancement. A digital perfusion simulation was developed to give a realistic representation of brain anatomy, artifacts, noise, scanner characteristics, and hemo-dynamic properties. This simulation includes a digital brain phantom, time-attenuation curves and noise parameters, a novel forward projection method for improved computational efficiency, and perfusion parameter calculation. Results: Our results show the feasibility of estimating perfusion parameters from a set of images reconstructed from slow scans, sparse data sets, and arc length scans as short as 60 degrees. The RoD framework significantly reduces noise and time-varying artifacts from inconsistent projections. Proper regularization and the use of overlapping reconstructed arcs can potentially further decrease bias and increase temporal resolution, respectively. Conclusions: A digital brain perfusion simulation with RoD imaging approach has been developed and supports the feasibility of using a CBCT head scanner for perfusion imaging. Future work will include testing with data acquired using a 3D-printed perfusion phantom currently and translation to preclinical and clinical studies.

  4. SU-E-I-10: Investigation On Detectability of a Small Target for Different Slice Direction of a Volumetric Cone Beam CT Image

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C; Han, M; Baek, J [Yonsei University, Incheon (Korea, Republic of)

    2015-06-15

    Purpose: To investigate the detectability of a small target for different slice direction of a volumetric cone beam CT image and its impact on dose reduction. Methods: Analytic projection data of a sphere object (1 mm diameter, 0.2/cm attenuation coefficient) were generated and reconstructed by FDK algorithm. In this work, we compared the detectability of the small target from four different backprojection Methods: hanning weighted ramp filter with linear interpolation (RECON 1), hanning weighted ramp filter with Fourier interpolation (RECON2), ramp filter with linear interpolation (RECON 3), and ramp filter with Fourier interpolation (RECON4), respectively. For noise simulation, 200 photons per measurement were used, and the noise only data were reconstructed using FDK algorithm. For each reconstructed volume, axial and coronal slice were extracted and detection-SNR was calculated using channelized Hotelling observer (CHO) with dense difference-of-Gaussian (D-DOG) channels. Results: Detection-SNR of coronal images varies for different backprojection methods, while axial images have a similar detection-SNR. Detection-SNR{sup 2} ratios of coronal and axial images in RECON1 and RECON2 are 1.33 and 1.15, implying that the coronal image has a better detectability than axial image. In other words, using coronal slices for the small target detection can reduce the patient dose about 33% and 15% compared to using axial slices in RECON 1 and RECON 2. Conclusion: In this work, we investigated slice direction dependent detectability of a volumetric cone beam CT image. RECON 1 and RECON 2 produced the highest detection-SNR, with better detectability in coronal slices. These results indicate that it is more beneficial to use coronal slice to improve detectability of a small target in a volumetric cone beam CT image. This research was supported by the MSIP (Ministry of Science, ICT and Future Planning), Korea, under the IT Consilience Creative Program (NIPA-2014-H0201

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

    Directory of Open Access Journals (Sweden)

    Iury Oliveira Castro

    2014-01-01

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

  6. Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.

    Science.gov (United States)

    Neves, Frederico Sampaio; Rovaris, Karla; Oliveira, Matheus Lima; Novaes, Pedro Duarte; de Freitas, Deborah Queiroz

    2014-04-01

    The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union.

  7. Ulcerated anterior maxillary swelling showing radiopaque bodies on cone beam computed tomography.

    Science.gov (United States)

    Costa, Fábio Wildson Gurgel; Vasconcelos, Marcelo Gadelha; de Queiroz, Lélia Maria Guedes; de Queiroz, Sormani Bento Fernandes; de Menezes, Alynne Vieira; Soares, Eduardo Costa Studart; Pereira, Karuza Maria Alves

    2013-11-01

    The calcifying epithelial odontogenic tumor (CEOT), also known as Pindborg tumor, is a rare benign tumor of epithelial origin of locally aggressive behavior, which represents less than 1% of all odontogenic tumors affecting the oral cavity. The lesion usually presents as a nonulcerated painless mass of slow growth, commonly affecting the posterior region of the mandible. Depending on the stages of development, CEOTs may present variable radiographic appearances. To date, a few number of cases affecting the anterior maxillary region have been published in the English-language literature. This article describes an interesting and rare case of an anterior ulcerated maxillary swelling diagnosed as a CEOT based on clinical, cone beam computed tomography and pathologic findings. Functional results were obtained with the surgical approach, and no recurrence of the lesion during a 2-year follow-up period was observed.

  8. Enhancement cone beam computed tomography filters improve in vitro periimplant dehiscence detection.

    Science.gov (United States)

    de-Azevedo-Vaz, Sergio Lins; Alencar, Phillipe Nogueira Barbosa; Rovaris, Karla; Campos, Paulo Sérgio Flores; Haiter-Neto, Francisco

    2013-11-01

    To investigate whether cone beam computed tomography filters would improve periimplant dehiscence detection. A hundred titanium implants were placed in bovine ribs in which defects simulating periimplant dehiscence had previously been created. After images acquisition, three oral radiologists assessed them with and without the following filters: Angio Sharpen high 5 × 5, Shadow, Sharpen 3 × 3, Sharpen Mild, and Smooth. The McNemar test verified the disagreement between all images versus the reference standard and original images versus images with filters; P detection using the original images and the Shadow filter disagreed from the reference standard (P Shadow, improved periimplant dehiscence detection. The Sharpen 3 × 3 filter was considered best for this task. Copyright © 2013 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

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

    2016-09-01

    Radiological anatomy education is an important aspect of the medical curriculum. The purpose of this study was to establish and demonstrate the use of plastinated anatomical specimens, specifically human hearts, for use in radiological anatomy education. Four human hearts were processed with routine plastination procedures at room temperature. Specimens were subjected to cone beam computed tomography and a graphics program (ER3D) was applied to generate 3D cardiac models. A comparison was conducted between plastinated hearts and their corresponding computer models based on a list of morphological cardiac features commonly studied in the gross anatomy laboratory. Results showed significant correspondence between plastinations and CBCT-generated 3D models (98 %; p anatomy education.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-15

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

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

    Directory of Open Access Journals (Sweden)

    Ankur Mahesh Banode

    2016-01-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Mounir Omami

    2015-01-01

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

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

    Science.gov (United States)

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

    2009-01-01

    Introduction In this study, we compared the precision of landmark identification using displays of multi-planar cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). Methods Twenty presurgical orthodontic patients were radiographed with conventional Ceph and CBCT techniques. Five observers plotted 24 landmarks using computer displays of multi-planer reconstruction (MPR) CBCT and Ceph views during separate sessions. Absolute differences between each observer’s plot and the mean of all observers were averaged as 1 measure of variability (ODM). The absolute difference of each observer from any other observer was averaged as a second measure of variability (DEO). ANOVA and paired t tests were used to analyze variability differences. Results Radiographic modality and landmark were significant at P definition of the landmarks in the third dimension. PMID:19732656

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

    Directory of Open Access Journals (Sweden)

    Evaldo Rodrigues

    2017-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Anil Munavalli

    2015-01-01

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

  17. Evaluation of volumetric changes of teeth in a Brazilian population by using cone beam computed tomography.

    Science.gov (United States)

    Porto, Lúcia Virgínia Mendonça Gomes; Celestino da Silva Neto, Joaquim; Anjos Pontual, Andrea Dos; Catunda, Raisa Queiroz

    2015-11-01

    The purpose of this study was to test the usefulness of some morphometric parameters of the teeth in 5 different age groups through images of Cone Beam CT. 118 upper central incisors clinically acquired of 60 women and 58 men aged between 22 and 70 years were selected. The hard tissue volume and the pulp cavity volume of each tooth was obtained and computed by the software DentalSlice(®) and the measures were assessed (pulp cavity volume, hard tissue volume, tooth volume and pulp cavity/tooth volume ratio). The pulp cavity volume and the pulp cavity/tooth volume ratio showed significant differences between age groups (p determination of 0.21 which suggests that there is a weak correlation between the pulp cavity/tooth volume ratio and age. Copyright © 2015 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

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

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

    2016-06-15

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Wang, Rong-yang; Han, Min; Liu, Hong; Wang, Chun-ling; Xian, Hong-hong; Zhang, Lei; Zhang, Shi-jie; Liu, Dong-xu

    2012-01-01

    To propose a method of establishing the reference mandibular plane (MP), which could be reestablished according to the coordinates of the reference points, and then facilitate the assessment of anterior alveolar morphology using cone beam computed tomography (CBCT), sixty patients with bimaxillary protrusion were randomly selected and CBCT scans were taken. The CBCT scans were transferred to Materialism’s interactive medical image control system 10.01 (MIMICS 10.01), and three dimensional models of the entire jaws were constructed. Reference points determining the reference MP were positioned in the coronal, axial, sagittal windows, and the points were exactly located by recording their coordinates in the interfaces of software. The reference MP provided high intra-observer reliability (Pearson’s r 0.992 to 0.999), and inter-observer reliability (intra-class correlation coefficients (ICCs) 0.996 to 0.999). PMID:23125087

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Shiraz Pasha

    2016-01-01

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

  3. Asymmetry assessment using cone beam CT. A Class I and Class II patient comparison.

    Science.gov (United States)

    Sievers, Matthew M; Larson, Brent E; Gaillard, Philippe R; Wey, Andrew

    2012-05-01

    To estimate possible differences in skeletal asymmetry between patients with skeletal Class I and skeletal Class II relationships. Cone beam computed tomography (CBCT) images were examined from 70 consecutive patients who presented for orthodontic care and fit the inclusion criteria. Asymmetry was quantified using an asymmetry index developed by Katsumata et al. Anatomic landmarks were defined and reference planes were established to determine the asymmetry of the landmarks using a constructed coordinate plane system. Thirty randomly selected patients were reanalyzed to assess the reliability of the method. Statistical analysis did not find any significant relationship between asymmetry and A-P skeletal relationship for any of the landmarks. Asymmetry index scores were reproducible within a certain range of agreement for each landmark. Based on this study, the discrepant jaw growth resulting in a Class II skeletal pattern results in no more skeletal asymmetry than Class I skeletal patterns.

  4. Clinical implementation of intraoperative cone-beam CT in head and neck surgery

    Science.gov (United States)

    Daly, M. J.; Chan, H.; Nithiananthan, S.; Qiu, J.; Barker, E.; Bachar, G.; Dixon, B. J.; Irish, J. C.; Siewerdsen, J. H.

    2011-03-01

    A prototype mobile C-arm for cone-beam CT (CBCT) has been translated to a prospective clinical trial in head and neck surgery. The flat-panel CBCT C-arm was developed in collaboration with Siemens Healthcare, and demonstrates both sub-mm spatial resolution and soft-tissue visibility at low radiation dose (e.g., soft-tissue visualization sufficient for intraoperative guidance, with additional artifact management (e.g., metal, scatter) promising further improvements. Clinical trial deployment suggests a role for intraoperative CBCT in guiding complex head and neck surgical tasks, including planning mandible and maxilla resection margins, guiding subcranial and endonasal approaches to skull base tumours, and verifying maxillofacial reconstruction alignment. Ongoing translational research into complimentary image-guidance subsystems include novel methods for real-time tool tracking, fusion of endoscopic video and CBCT, and deformable registration of preoperative volumes and planning contours with intraoperative CBCT.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  6. A technique for transferring a patient's smile line to a cone beam computed tomography (CBCT) image.

    Science.gov (United States)

    Bidra, Avinash S

    2014-08-01

    Fixed implant-supported prosthodontic treatment for patients requiring a gingival prosthesis often demands that bone and implant levels be apical to the patient's maximum smile line. This is to avoid the display of the prosthesis-tissue junction (the junction between the gingival prosthesis and natural soft tissues) and prevent esthetic failures. Recording a patient's lip position during maximum smile is invaluable for the treatment planning process. This article presents a simple technique for clinically recording and transferring the patient's maximum smile line to cone beam computed tomography (CBCT) images for analysis. The technique can help clinicians accurately determine the need for and amount of bone reduction required with respect to the maximum smile line and place implants in optimal positions. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-15

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

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

    Science.gov (United States)

    Rosen, E; Tsesis, I

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-15

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

  10. Survival prediction of non-small cell lung cancer patients using radiomics analyses of cone-beam CT images

    DEFF Research Database (Denmark)

    van Timmeren, Janna E; Leijenaar, Ralph T H; van Elmpt, Wouter

    2017-01-01

    BACKGROUND AND PURPOSE: In this study we investigated the interchangeability of planning CT and cone-beam CT (CBCT) extracted radiomic features. Furthermore, a previously described CT based prognostic radiomic signature for non-small cell lung cancer (NSCLC) patients using CBCT based features was...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-06-15

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

  12. Image and surgery-related costs comparing cone beam CT and panoramic imaging before removal of impacted mandibular third molars

    DEFF Research Database (Denmark)

    Petersen, Lars Bo; Olsen, Kim Rose; Christensen, Jennifer Heather

    2014-01-01

    Objectives: The aim of this prospective clinical study was to derive the absolute and relative costs of cone beam CT (CBCT) and panoramic imaging before removal of an impacted mandibular third molar. Furthermore, the study aimed to analyse the influence of different cost-setting scenarios on the ...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    NARCIS (Netherlands)

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

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  1. A novel method for megavoltage scatter correction in cone-beam CT acquired concurrent with rotational irradiation

    NARCIS (Netherlands)

    van Herk, Marcel; Ploeger, Lennert; Sonke, Jan-Jakob

    2011-01-01

    Acquisition of cone-beam CT (CBCT) concurrent with VMAT results in scatter of the megavoltage (MV) beam onto the kilovoltage (kV) detector deteriorating CBCT image quality. The aim of this paper is to develop a method to estimate and correct for MV scatter reaching the kV panel. The correction

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

    NARCIS (Netherlands)

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

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

  3. Reduction of Cone-Beam CT scan time without compromising the accuracy of the image registration in IGRT

    DEFF Research Database (Denmark)

    Westberg, Jonas; Jensen, Henrik R; Bertelsen, Anders

    2010-01-01

    In modern radiotherapy accelerators are equipped with 3D cone-beam CT (CBCT) which is used to verify patient position before treatment. The verification is based on an image registration between the CBCT acquired just before treatment and the CT scan made for the treatment planning. The purpose...

  4. The ability of cone-beam computed tomography to detect simulated buccal and lingual recesses in root canals

    NARCIS (Netherlands)

    Liang, Y.H.; Yuan, M.; Li, G.; Shemesh, H.; Wesselink, P.R.; Wu, M.K.

    2012-01-01

    Aim  To compare the ability of cone-beam computed tomography (CBCT) and digital periapical radiographs (PR) to detect simulated tissue-occupied recesses in root canals. Methodology  A standard canal was created in 30 extracted mandibular premolar roots. Each root was longitudinally split into buccal

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

    NARCIS (Netherlands)

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

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

  6. Inter- and intraobserver reproducibility of buccal bone measurements at dental implants with cone beam computed tomography in the esthetic region

    NARCIS (Netherlands)

    Slagter, Kirsten W; Raghoebar, Gerry M; Vissink, Arjan; Meijer, Henny J A

    2015-01-01

    BACKGROUND: Sufficient buccal bone is important for optimal esthetic results of implant treatment in the anterior region. It can be measured with cone beam computed tomography (CBCT), but background scattering and problems with standardization of the measurements are encountered. The aim was to

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    NARCIS (Netherlands)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

    Buchgreitz, J; Buchgreitz, M; Mortensen, D

    2016-01-01

    AIM: To evaluate ex vivo, the accuracy of a preparation procedure planned for teeth with pulp canal obliteration (PCO) using a guide rail concept based on a cone-beam computed tomography (CBCT) scan merged with an optical surface scan. METHODOLOGY: A total of 48 teeth were mounted in acrylic bloc...

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

    NARCIS (Netherlands)

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

    2017-01-01

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

  11. Cone beam computed tomography guidance for setup of patients receiving accelerated partial breast irradiation.

    Science.gov (United States)

    White, Elizabeth A; Cho, John; Vallis, Katherine A; Sharpe, Michael B; Lee, Grace; Blackburn, Helen; Nageeti, Tahani; McGibney, Carol; Jaffray, David A

    2007-06-01

    To evaluate the role of cone-beam CT (CBCT) guidance for setup error reduction and soft tissue visualization in accelerated partial breast irradiation (APBI). Twenty patients were recruited for the delivery of radiotherapy to the postoperative cavity (3850 cGy in 10 fractions over 5 days) using an APBI technique. Cone-beam CT data sets were acquired after an initial skin-mark setup and before treatment delivery. These were registered online using the ipsilateral lung and external contours. Corrections were executed for translations exceeding 3 mm. The random and systematic errors associated with setup using skin-marks and setup using CBCT guidance were calculated and compared. A total of 315 CBCT data sets were analyzed. The systematic errors for the skin-mark setup were 2.7, 1.7, and 2.4 mm in the right-left, anterior-posterior, and superior-inferior directions, respectively. These were reduced to 0.8, 0.7, and 0.8 mm when CBCT guidance was used. The random errors were reduced from 2.4, 2.2, and 2.9 mm for skin-marks to 1.5, 1.5, and 1.6 mm for CBCT guidance in the right-left, anterior-posterior, and superior-inferior directions, respectively. A skin-mark setup for APBI patients is sufficient for current planning target volume margins for the population of patients studied here. Online CBCT guidance minimizes the occurrence of large random deviations, which may have a greater impact for the accelerated fractionation schedule used in APBI. It is also likely to permit a reduction in planning target volume margins and provide skin-line visualization and dosimetric evaluation of cardiac and lung volumes.

  12. In vitro evaluation of three electronic apex locators using conventional methods and cone beam computed tomography.

    Science.gov (United States)

    Mrasori, S; Budina, R; Dragidella, F

    2014-01-01

    The aim of this paper was to evaluate the measurement accuracy of three electronic apex locators by digital radiography, stereomicroscope and cone beam computed tomography (CBCT). This in vitro experimental analytic-descriptive study included 90 extracted permanent teeth with mature apices from the inter-canine region, divided into three groups. In vitro electronic root canal measurement was utilized using three different apex locators: ProPex Dentsply, Apex NRG Blue and Romi Apex 15A. After digital radiographic imaging and measurements Cone Beam Computer Tomography (CBCT) imaging with voxel edge size 0.125 mm was utilized and finally the apical portion of the root is grounded (5 mm) along its axis to prepare it for stereomicroscopic measurements. The performed test of significance shows that there is no difference between the apex locators and the control length as measured by computed digital radiography (CDR), P-values of the t-tests are all >0.05. The t-tests showed that there is no significant differences between the measurements conducted by stereomicroscope and the measurements results obtained using CBCT; measurements performed by the three apex locators (Propex, NRG-Blue, and Rami Apex), were accurate within 0.5 mm 87%, 93%, and 87% of the time, respectively. The statistical analysis showed no significant differences between the three tested apex locators (P>0.05). Based on the conditions of the present study, it can be concluded that all three apex locators (ProPex Dentsply, Apex NRG Blu and Romi Apex 15A) have demonstrated accurate and dependable measurements performed in vitro conditions.

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

    Directory of Open Access Journals (Sweden)

    Najmeh Anbiaee

    2016-03-01

    Full Text Available 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.Keywords: Cone Beam Computed Tomography; Mandibular Nerve; Mandible

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

    Directory of Open Access Journals (Sweden)

    Timothy Olding

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

  16. Magnitude and effects of X-ray scatter of a cone-beam micro-CT for small animal imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Y.C. [Institute of Nuclear Energy Research, Longtan 32546, Taiwan (China); Jan, M.L. [Institute of Nuclear Energy Research, Longtan 32546, Taiwan (China); Chen, K.W. [Institute of Nuclear Energy Research, Longtan 32546, Taiwan (China); Cheng, Y.D. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 30043, Taiwan (China); Chuang, K.S. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu 30043, Taiwan (China); Fu, Y.K. [Institute of Nuclear Energy Research, Longtan 32546, Taiwan (China)]. E-mail: fufrank@iner.gov.tw

    2006-12-20

    We have developed a micro-CT system to provide high-resolution and anatomic information to combine with a microPET'' (registered) R4 system. This study was to evaluate the magnitude and effects of scatter for low kVp X-ray in this cone-beam micro-CT system. Slit collimators were used to simulate fan-beam micro-CT for comparison. The magnitudes of X-ray scatter were measured using the beam-stop method and were estimated by polynomial-fitting extrapolation to 0 mm size of stoppers. The scatter-to-primary ratio at center of the cone-beam system were 45% and 20% for rat and mouse phantoms, respectively, and were reduced to 5.86% and 4.2% in fan-beam geometric setup. The effects of X-ray scatter on image uniformity and contrast ratio were evaluated also. The uniformity response was examined by the profile of the reconstructed image. The degrees of 'cupping' in the fan-beam and cone-beam conditions were 1.75% and 3.81%, respectively, in rat phantom. A contrast phantom consisting of four inserts with physical densities similar to that of acrylic was used for measuring the effect of X-ray scatter on image contrast. Contrast ratios of the inserts and acrylic in cone-beam setup degraded 36.9% in average compared with fan-beam setup. A tumor-bearing mouse was scanned by the micro-CT system. The tumor-to-background contrast ratios were measured to be 0.331 and 0.249, respectively, with fan-beam and cone-beam setups.

  17. Observer Evaluation of a Metal Artifact Reduction Algorithm Applied to Head and Neck Cone Beam Computed Tomographic Images

    Energy Technology Data Exchange (ETDEWEB)

    Korpics, Mark; Surucu, Murat; Mescioglu, Ibrahim; Alite, Fiori; Block, Alec M.; Choi, Mehee; Emami, Bahman; Harkenrider, Matthew M.; Solanki, Abhishek A.; Roeske, John C., E-mail: jroeske@lumc.edu

    2016-11-15

    Purpose and Objectives: To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer. Methods and Materials: An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants. Image quality with respect to metal artifacts was evaluated subjectively and objectively. First, 6 independent radiation oncologists were asked to rank randomly sorted blinded images (before and after metal artifact reduction) using a 5-point rating scale (1 = severe artifacts; 5 = no artifacts). Second, the standard deviation of different regions of interest (ROI) within each image was calculated and compared with the mean rating scores. Results: The interpolation-substitution technique successfully reduced metal artifacts in 70% of the cases. From a total of 60 images from 15 H&N cancer patients undergoing image guided radiation therapy, the mean rating score on the uncorrected images was 2.3 ± 1.1, versus 3.3 ± 1.0 for the corrected images. The mean difference in ranking score between uncorrected and corrected images was 1.0 (95% confidence interval: 0.9-1.2, P<.05). The standard deviation of each ROI significantly decreased after artifact reduction (P<.01). Moreover, a negative correlation between the mean rating score for each image and the standard deviation of the oral cavity and bilateral cheeks was observed. Conclusion: The interpolation-substitution algorithm is efficient and effective for reducing metal artifacts caused by dental fillings and implants on CBCT images, as demonstrated by the statistically significant increase in observer image quality ranking and by the decrease in ROI standard deviation between uncorrected and corrected images.

  18. Automated 2D-3D registration of a radiograph and a cone beam CT using line-segment enhancementa)

    Science.gov (United States)

    Munbodh, Reshma; Jaffray, David A.; Moseley, Douglas J.; Chen, Zhe; Knisely, Jonathan P. S.; Cathier, Pascal; Duncan, James S.

    2009-01-01

    The objective of this study was to develop a fully automated two-dimensional (2D)–three-dimensional (3D) registration framework to quantify setup deviations in prostate radiation therapy from cone beam CT (CBCT) data and a single AP radiograph. A kilovoltage CBCT image and kilovoltage AP radiograph of an anthropomorphic phantom of the pelvis were acquired at 14 accurately known positions. The shifts in the phantom position were subsequently estimated by registering digitally reconstructed radiographs (DRRs) from the 3D CBCT scan to the AP radiographs through the correlation of enhanced linear image features mainly representing bony ridges. Linear features were enhanced by filtering the images with “sticks,” short line segments which are varied in orientation to achieve the maximum projection value at every pixel in the image. The mean (and standard deviations) of the absolute errors in estimating translations along the three orthogonal axes in millimeters were 0.134 (0.096) AP(out-of-plane), 0.021 (0.023) ML and 0.020 (0.020) SI. The corresponding errors for rotations in degrees were 0.011 (0.009) AP, 0.029 (0.016) ML (out-of-plane), and 0.030 (0.028) SI (out-of-plane). Preliminary results with megavoltage patient data have also been reported. The results suggest that it may be possible to enhance anatomic features that are common to DRRs from a CBCT image and a single AP radiography of the pelvis for use in a completely automated and accurate 2D-3D registration framework for setup verification in prostate radiotherapy. This technique is theoretically applicable to other rigid bony structures such as the cranial vault or skull base and piecewise rigid structures such as the spine. PMID:16752576

  19. Assessment of the anterior loop of mental nerve in an Iranian population using cone beam computed tomography scan.

    Science.gov (United States)

    Kheir, Mitra Karbasi; Sheikhi, Mahnaz

    2017-01-01

    The anterior loop is an important structure in the interforaminal area of the mandible. The aim of the present study was to assess the prevalence and length of the anterior loop of mental nerve using cone beam computed tomography (CBCT) scan and to compare the differences between age, gender, and side. A total of 180 projections were analyzed in different sectional planes. The inferior alveolar nerve was determined. To measure the length of anterior loop in tangential plane, two parallel lines from the anterior point of mental foramen and anterior point of anterior loop were drawn. The distance between these two lines was measured by drawing a perpendicular line on them. The data were analyzed by SPSS (version 22). McNemar's test, Chi-square test, and t-test were performed to compare the significance of findings regarding side, age, and gender. P < 0.05 was considered statistically significant. The results showed that 32.8% of images had anterior loop. The mean lengths of anterior loop in the right and left sides were 2.69 mm (standard deviation [SD] = 1.56) and 2.36 mm (SD = 1.16), respectively. There were no statistically significant differences between the mean lengths of the anterior loop in both sides (P = 0.18). Great care is required when placing implants in proximity to mental foramen to avoid anterior loop injury. Because of the variations of anterior loop length in each patient, a fixed distance anterior to the mental foramen is not safe, and the anterior loop length should be determined for each individual. The use of CBCT provides accurate measurements of the length of anterior loop.

  20. Cone-beam CT of traumatic brain injury using statistical reconstruction with a post-artifact-correction noise model

    Science.gov (United States)

    Dang, H.; Stayman, J. W.; Sisniega, A.; Xu, J.; Zbijewski, W.; Yorkston, J.; Aygun, N.; Koliatsos, V.; Siewerdsen, J. H.

    2015-03-01

    Traumatic brain injury (TBI) is a major cause of death and disability. The current front-line imaging modality for TBI detection is CT, which reliably detects intracranial hemorrhage (fresh blood contrast 30-50 HU, size down to 1 mm) in non-contrast-enhanced exams. Compared to CT, flat-panel detector (FPD) cone-beam CT (CBCT) systems offer lower cost, greater portability, and smaller footprint suitable for point-of-care deployment. We are developing FPD-CBCT to facilitate TBI detection at the point-of-care such as in emergent, ambulance, sports, and military applications. However, current FPD-CBCT systems generally face challenges in low-contrast, soft-tissue imaging. Model-based reconstruction can improve image quality in soft-tissue imaging compared to conventional filtered back-projection (FBP) by leveraging high-fidelity forward model and sophisticated regularization. In FPD-CBCT TBI imaging, measurement noise characteristics undergo substantial change following artifact correction, resulting in non-negligible noise amplification. In this work, we extend the penalized weighted least-squares (PWLS) image reconstruction to include the two dominant artifact corrections (scatter and beam hardening) in FPD-CBCT TBI imaging by correctly modeling the variance change following each correction. Experiments were performed on a CBCT test-bench using an anthropomorphic phantom emulating intra-parenchymal hemorrhage in acute TBI, and the proposed method demonstrated an improvement in blood-brain contrast-to-noise ratio (CNR = 14.2) compared to FBP (CNR = 9.6) and PWLS using conventional weights (CNR = 11.6) at fixed spatial resolution (1 mm edge-spread width at the target contrast). The results support the hypothesis that FPD-CBCT can fulfill the image quality requirements for reliable TBI detection, using high-fidelity artifact correction and statistical reconstruction with accurate post-artifact-correction noise models.

  1. A surgical navigation system for non-contact diffuse optical tomography and intraoperative cone-beam CT

    Science.gov (United States)

    Daly, Michael J.; Muhanna, Nidal; Chan, Harley; Wilson, Brian C.; Irish, Jonathan C.; Jaffray, David A.

    2014-02-01

    A freehand, non-contact diffuse optical tomography (DOT) system has been developed for multimodal imaging with intraoperative cone-beam CT (CBCT) during minimally-invasive cancer surgery. The DOT system is configured for near-infrared fluorescence imaging with indocyanine green (ICG) using a collimated 780 nm laser diode and a nearinfrared CCD camera (PCO Pixelfly USB). Depending on the intended surgical application, the camera is coupled to either a rigid 10 mm diameter endoscope (Karl Storz) or a 25 mm focal length lens (Edmund Optics). A prototype flatpanel CBCT C-Arm (Siemens Healthcare) acquires low-dose 3D images with sub-mm spatial resolution. A 3D mesh is extracted from CBCT for finite-element DOT implementation in NIRFAST (Dartmouth College), with the capability for soft/hard imaging priors (e.g., segmented lymph nodes). A stereoscopic optical camera (NDI Polaris) provides real-time 6D localization of reflective spheres mounted to the laser and camera. Camera calibration combined with tracking data is used to estimate intrinsic (focal length, principal point, non-linear distortion) and extrinsic (translation, rotation) lens parameters. Source/detector boundary data is computed from the tracked laser/camera positions using radiometry models. Target registration errors (TRE) between real and projected boundary points are ~1-2 mm for typical acquisition geometries. Pre-clinical studies using tissue phantoms are presented to characterize 3D imaging performance. This translational research system is under investigation for clinical applications in head-and-neck surgery including oral cavity tumour resection, lymph node mapping, and free-flap perforator assessment.

  2. Implementation of dual- and triple-energy cone-beam micro-CT for postreconstruction material decomposition.

    Science.gov (United States)

    Granton, P V; Pollmann, S I; Ford, N L; Drangova, M; Holdsworth, D W

    2008-11-01

    Micro-CT has become a powerful tool for small animal research, having the ability to obtain high-resolution in vivo and ex vivo images for analyzing bone mineral content, organ vasculature, and bone microarchitecture extraction. The use of exogenous contrast agents further extends the use of micro-CT techniques, but despite advancements in contrast agents, single-energy micro-CT is still limited in cases where two different materials share similar grey-scale intensity values. This study specifically addresses the development of multiple-energy cone-beam micro-CT, for applications where bone must be separated from blood vessels filled with a Pb-based contrast material (Microfil) in ex vivo studies of rodents and tissue specimens. The authors report the implementation of dual- and triple-energy CT algorithms for material-specific imaging using postreconstruction decomposition of micro-CT data; the algorithms were implemented on a volumetric cone-beam micro-CT scanner (GE Locus Ultra). For the dual-energy approach, extrinsic filtration was applied to the x-ray beam to produce spectra with different proportions of x rays above the K edge of Pb. The optimum x-ray tube energies (140 kVp filtered with 1.45 mm Cu and 96 kVp filtered with 0.3 mm Pb) that maximize the contrast between bone and Microfil were determined through numerical simulation. For the triple-energy decomposition, an additional low-energy spectrum (70 kVp, no added filtration) was used. The accuracy of decomposition was evaluated through simulations and experimental verification of a phantom containing a cortical bone simulating material (SB3), Microfil, and acrylic. Using simulations and phantom experiments, an accuracy greater than 95% was achieved in decompositions of bone and Microfil (for noise levels lower than 11 HU), while soft tissue was separated with accuracy better than 99%. The triple-energy technique demonstrated a slightly higher, but not significantly different, decomposition accuracy than

  3. TH-A-18C-09: Ultra-Fast Monte Carlo Simulation for Cone Beam CT Imaging of Brain Trauma

    Energy Technology Data Exchange (ETDEWEB)

    Sisniega, A; Zbijewski, W; Stayman, J [Department of Biomedical Engineering, Johns Hopkins University (United States); Yorkston, J [Carestream Health (United States); Aygun, N [Department of Radiology, Johns Hopkins University (United States); Koliatsos, V [Department of Neurology, Johns Hopkins University (United States); Siewerdsen, J [Department of Biomedical Engineering, Johns Hopkins University (United States); Department of Radiology, Johns Hopkins University (United States)

    2014-06-15

    Purpose: Application of cone-beam CT (CBCT) to low-contrast soft tissue imaging, such as in detection of traumatic brain injury, is challenged by high levels of scatter. A fast, accurate scatter correction method based on Monte Carlo (MC) estimation is developed for application in high-quality CBCT imaging of acute brain injury. Methods: The correction involves MC scatter estimation executed on an NVIDIA GTX 780 GPU (MC-GPU), with baseline simulation speed of ~1e7 photons/sec. MC-GPU is accelerated by a novel, GPU-optimized implementation of variance reduction (VR) techniques (forced detection and photon splitting). The number of simulated tracks and projections is reduced for additional speed-up. Residual noise is removed and the missing scatter projections are estimated via kernel smoothing (KS) in projection plane and across gantry angles. The method is assessed using CBCT images of a head phantom presenting a realistic simulation of fresh intracranial hemorrhage (100 kVp, 180 mAs, 720 projections, source-detector distance 700 mm, source-axis distance 480 mm). Results: For a fixed run-time of ~1 sec/projection, GPU-optimized VR reduces the noise in MC-GPU scatter estimates by a factor of 4. For scatter correction, MC-GPU with VR is executed with 4-fold angular downsampling and 1e5 photons/projection, yielding 3.5 minute run-time per scan, and de-noised with optimized KS. Corrected CBCT images demonstrate uniformity improvement of 18 HU and contrast improvement of 26 HU compared to no correction, and a 52% increase in contrast-tonoise ratio in simulated hemorrhage compared to “oracle” constant fraction correction. Conclusion: Acceleration of MC-GPU achieved through GPU-optimized variance reduction and kernel smoothing yields an efficient (<5 min/scan) and accurate scatter correction that does not rely on additional hardware or simplifying assumptions about the scatter distribution. The method is undergoing implementation in a novel CBCT dedicated to brain

  4. Implementation and evaluation of two helical CT reconstruction algorithms in CIVA

    Science.gov (United States)

    Banjak, H.; Costin, M.; Vienne, C.; Kaftandjian, V.

    2016-02-01

    The large majority of industrial CT systems reconstruct the 3D volume by using an acquisition on a circular trajec-tory. However, when inspecting long objects which are highly anisotropic, this scanning geometry creates severe artifacts in the reconstruction. For this reason, the use of an advanced CT scanning method like helical data acquisition is an efficient way to address this aspect known as the long-object problem. Recently, several analytically exact and quasi-exact inversion formulas for helical cone-beam reconstruction have been proposed. Among them, we identified two algorithms of interest for our case. These algorithms are exact and of filtered back-projection structure. In this work we implemented the filtered-backprojection (FBP) and backprojection-filtration (BPF) algorithms of Zou and Pan (2004). For performance evaluation, we present a numerical compari-son of the two selected algorithms with the helical FDK algorithm using both complete (noiseless and noisy) and truncated data generated by CIVA (the simulation platform for non-destructive testing techniques developed at CEA).

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Mehrdad Panjnoush

    2016-11-01

    Full Text Available 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.Keywords: Anatomy; Cone-Beam Computed Tomography; Dental Implants; Maxilla

  7. Palatal mucosal measurements in a Japanese population using cone-beam computed tomography.

    Science.gov (United States)

    Ueno, Daisuke; Sekiguchi, Rei; Morita, Masayuki; Jayawardena, Asiri; Shinpo, Satoro; Sato, Junichi; Kobayashi, Kaoru

    2014-01-01

    Although assessment of entire palatal mucosal thickness is important in many dental procedures, available data are mostly limited to the lateral aspect of the palate. The objective of this study was to use cone-beam computed tomography (CBCT) to perform a comprehensive analysis of the palatal mucosal thickness from the gingival margin to the mid-palatine suture in a Japanese population. Associations of palatal mucosal thickness with the palatal vault depth were also examined. Measurements on the coronal plane were obtained from 44 adults with 3-mm interval in the canine (Ca), first premolar (P1), second premolar (P2), midpoint between first and second molars (M1d), first molar (M1), and second molar (M2). Furthermore, the location of greater palatine foramen (GPF) and palatine groove (PG) were also investigated. Canine region did not show a significant difference throughout measured points. P1, P2, and all molar regions were thickest at 9, 12, and 12 mm from the gingival margin, respectively. At 3 and 6 mm, Ca, P1, and P2 showed significantly greater thickness than the molar region. At 9 mm, P1 demonstrated a greater thickness than M1d, and P2 was greater than M1 and Mi. At 12 and 15 mm, P1 was thinner than P2, M1, and M2, whereas P2 was thinner than M2. M1 was thinner than M2. The high-vault group showed a significantly greater thickness than the low-vault group. In majority of subjects, GPF and PG were identified in second molar and first premolar to first molar, respectively. Palatal mucosa in a Japanese population was the thickest in canine to premolar regions at 9 to 12 mm from the gingival margin. Identification of GPF and PG using CBCT can assist diagnosis of palate seems to minimize surgical complications. This study evaluated the thickness of palatal mucosa in a Japanese population using cone-beam computed tomography, covering a wide range. Canine to second premolar regions are the most suitable in harvesting palatal mucosa for the purpose of soft tissue

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

    Science.gov (United States)

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

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

    Energy Technology Data Exchange (ETDEWEB)

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C. [Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    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

  10. Analisis gambaran histogramdan densitas kamar pulpa pada gigi suspek pulpitis reversibel dan ireversibel dengan menggunakan radiografi cone beam computed tomography (Histogram and density analysis of irreversible and reversible pulpitissuspected tooth using cone beam computed tomography radiography)

    OpenAIRE

    Lusi Epsilawati; Suhardjo Sitam; Sam Belly; Fahmi Oscandar

    2014-01-01

    Inflammation of the pulp is most common and difficult to diagnose. For it radiographs is necessary. One attempt to do is to assess its histogram and density. Radiography equipment that has the ability to analyze is cone beam computed tomography (CBCT). The purpose of this study is to analyze radiograph of the pulp chamber histogram: peak value, grayscale and trends , as well as the density on the condition reversible and irreversible pulpitis condition. The population of this ...

  11. TH-A-18C-04: Ultrafast Cone-Beam CT Scatter Correction with GPU-Based Monte Carlo Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y [UT Southwestern Medical Center, Dallas, TX (United States); Southern Medical University, Guangzhou (China); Bai, T [UT Southwestern Medical Center, Dallas, TX (United States); Xi' an Jiaotong University, Xi' an (China); Yan, H; Ouyang, L; Wang, J; Pompos, A; Jiang, S; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States); Zhou, L [Southern Medical University, Guangzhou (China)

    2014-06-15

    Purpose: Scatter artifacts severely degrade image quality of cone-beam CT (CBCT). We present an ultrafast scatter correction framework by using GPU-based Monte Carlo (MC) simulation and prior patient CT image, aiming at automatically finish the whole process including both scatter correction and reconstructions within 30 seconds. Methods: The method consists of six steps: 1) FDK reconstruction using raw projection data; 2) Rigid Registration of planning CT to the FDK results; 3) MC scatter calculation at sparse view angles using the planning CT; 4) Interpolation of the calculated scatter signals to other angles; 5) Removal of scatter from the raw projections; 6) FDK reconstruction using the scatter-corrected projections. In addition to using GPU to accelerate MC photon simulations, we also use a small number of photons and a down-sampled CT image in simulation to further reduce computation time. A novel denoising algorithm is used to eliminate MC scatter noise caused by low photon numbers. The method is validated on head-and-neck cases with simulated and clinical data. Results: We have studied impacts of photo histories, volume down sampling factors on the accuracy of scatter estimation. The Fourier analysis was conducted to show that scatter images calculated at 31 angles are sufficient to restore those at all angles with <0.1% error. For the simulated case with a resolution of 512×512×100, we simulated 10M photons per angle. The total computation time is 23.77 seconds on a Nvidia GTX Titan GPU. The scatter-induced shading/cupping artifacts are substantially reduced, and the average HU error of a region-of-interest is reduced from 75.9 to 19.0 HU. Similar results were found for a real patient case. Conclusion: A practical ultrafast MC-based CBCT scatter correction scheme is developed. The whole process of scatter correction and reconstruction is accomplished within 30 seconds. This study is supported in part by NIH (1R01CA154747-01), The Core Technology Research

  12. Image-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    Science.gov (United States)

    Unberath, Mathias; Choi, Jang-Hwan; Berger, Martin; Maier, Andreas; Fahrig, Rebecca

    2015-03-01

    We previously introduced four fiducial marker-based strategies to compensate for involuntary knee-joint motion during weight-bearing C-arm CT scanning of the lower body. 2D methods showed significant reduction of motion- related artifacts, but 3D methods worked best. However, previous methods led to increased examination times and patient discomfort caused by the marker attachment process. Moreover, sub-optimal marker placement may lead to decreased marker detectability and therefore unstable motion estimates. In order to reduce overall patient discomfort, we developed a new image-based 2D projection shifting method. A C-arm cone-beam CT system was used to acquire projection images of five healthy volunteers at various flexion angles. Projection matrices for the horizontal scanning trajectory were calibrated using the Siemens standard PDS-2 phantom. The initial reconstruction was forward projected using maximum-intensity projections (MIP), yielding an estimate of a static scan. This estimate was then used to obtain the 2D projection shifts via registration. For the scan with the most motion, the proposed method reproduced the marker-based results with a mean error of 2.90 mm +/- 1.43 mm (compared to a mean error of 4.10 mm +/- 3.03 mm in the uncorrected case). Bone contour surrounding modeling clay layer was improved. The proposed method is a first step towards automatic image-based, marker-free motion-compensation.

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

    Directory of Open Access Journals (Sweden)

    Enas Anter

    2016-01-01

    Full Text Available Systematic review of literature was made to assess the extent of accuracy of cone beam computed tomography (CBCT as a tool for measurement of alveolar bone loss in periodontal defect. A systematic search of PubMed electronic database and a hand search of open access journals (from 2000 to 2015 yielded abstracts that were potentially relevant. The original articles were then retrieved and their references were hand searched for possible missing articles. Only articles that met the selection criteria were included and criticized. The initial screening revealed 47 potentially relevant articles, of which only 14 have met the selection criteria; their CBCT average measurements error ranged from 0.19 mm to 1.27 mm; however, no valid meta-analysis could be made due to the high heterogeneity between the included studies. Under the limitation of the number and strength of the available studies, we concluded that CBCT provides an assessment of alveolar bone loss in periodontal defect with a minimum reported mean measurements error of 0.19 ± 0.11 mm and a maximum reported mean measurements error of 1.27 ± 1.43 mm, and there is no agreement between the studies regarding the direction of the deviation whether over or underestimation. However, we should emphasize that the evidence to this data is not strong.

  14. Management of Oehler’s Type III Dens Invaginatus Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Jaya Ranganathan

    2016-01-01

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

  15. Oropharyngeal airway in children with Class III malocclusion evaluated by cone-beam computed tomography.

    Science.gov (United States)

    Iwasaki, Tomonori; Hayasaki, Haruaki; Takemoto, Yoshihiko; Kanomi, Ryuzo; Yamasaki, Youichi

    2009-09-01

    Upper airway size is increasingly recognized as an important factor in malocclusion. However, children with Class III malocclusion are somewhat neglected compared with those with a Class II skeletal pattern. Therefore, the purpose of this study was to establish the characteristic shape of the oropharyngeal airway (OA) in children with Class III malocclusion. The sample comprised 45 children (average age, 8.6 +/- 1.0 years) divided into 2 groups: 25 with Class I and 20 with Class III malocclusions. OA size of each group was evaluated by cone-beam computed tomography. Cluster analysis, based on OA shape, redivided the subjects into wide, square, and long types. The distributions of Class I and Class III subjects were compared among the types. The Class III group showed statistically larger OA area and width compared with the Class I group. Area was positively correlated with Class III severity. The square type included 84% of the Class I malocclusions but only 30% of the Class III malocclusions, indicating that the OA in Class III malocclusion tends to be flat. The Class III malocclusion is associated with a large and flat OA compared with the Class I malocclusion.

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

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    Abdel-Wahed, Nagla' a; Abo-Taleb, Noha Saleh Mahmoud [Oral and Maxillofacial Radiology, Faculty of Oral and Dental Medicine, Cairo University, Cairo (Korea, Republic of); Amer, Maha E. [Oral and Maxillofacial Radiology, Faculty of Dentistry, Minia University, El Menia City (Korea, Republic of)

    2013-03-15

    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. 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. 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. 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.

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

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

    2016-10-15

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

  18. ANATOMICAL VARIATIONS FINDINGS ON CONE BEAM-COMPUTED TOMOGRAPHY IN CLEFT LIP AND PALATE PATIENTS

    Directory of Open Access Journals (Sweden)

    Yllka DECOLLI

    2015-09-01

    Full Text Available Introduction: Cone beam computed tomography (CBCT is frequently used in surgery treatment planning in patients with cleft lip and palate (CLP. The aim of this study was to investigate the presence of different anatomical variations of patients with cleft lip and palate using CBCT images. Materials and method: CBCTs taken from consecutive patients (n =25; mean age 10.7±4 years, range 6.5–23 years with a non-syndromic cleft lip and palate (CLP, between June 2014-2015, were systematically evaluated. Sinuses, nasopharynx, oropharynx, hypopharynx, temporo-mandibular joint (TMJ, maxilla and mandible were checked for incidental findings. Results: On 90.1 % of the CBCTs, incidental findings were found. The most prevalent ones were airway/sinus findings (78.1%, followed by dental problems, e.g. missing teeth (54%, nasal septum deviation (93%, middle ear and mastoid opacification, suggestive for otitis media (8% and (chronic mastoiditis (7%, abnormal TMJ anatomy (4.3%. Conclusions: Incidental findings are common on CBCTs in cleft lip and palate patients. Compared with the literature, CLP patients have more dental, nasal and ear problems. The CBCT scan should be reviewed by all specialists in the CLP team, stress being laid on their specific background knowledge concerning symptoms and treatment of these patients.

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

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    Sorapong Aootaphao

    2016-01-01

    Full Text Available Soft tissue images from portable cone beam computed tomography (CBCT scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.

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

    Science.gov (United States)

    Estrela, Carlos; Bueno, Mike Reis; Porto, Olavo César Lyra; Rodrigues, Cleomar Donizeth; Pécora, Jesus Djalma

    2009-01-01

    The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at pposts, AP was observed in 15.06%, 18.78% and 7.95% using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20%, 26.40% and 11.84% observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92%) by periapical radiography and in 614 (60.19%) by CBCT scans (pposts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79%). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used.

  1. Evaluation of cone beam computed tomography and periapical radiography in the diagnosis of root resorption.

    Science.gov (United States)

    Lima, T F; Gamba, T O; Zaia, A A; Soares, A J

    2016-12-01

    This study aimed to evaluate the accuracy of cone beam computed tomography (CBCT) and periapical radiography in diagnosing root resorption and verify the influence of filling material in detecting these lesions. Digital periapical radiographs and CBCT images of patients with root resorption and a history of dental trauma from a radiology clinic were reviewed retrospectively. The sample comprised 40 teeth with root resorption and 20 normal teeth as controls. Images were analysed by two radiologists and two endodontists. The sensitivity, specificity and accuracy were determined. The kappa coefficient assessed interobserver agreement and the t test determined significant differences between the imaging methods. The accuracy of CBCT in diagnosing external (P = 0.0144) and internal (P = 0.0038) inflammatory resorption was significantly higher than for periapical radiography. For replacement resorption, no statistical difference was noted (P > 0.05). In endodontically treated teeth, CBCT was statistically superior in diagnosing root resorption (P = 0.0138). CBCT was superior to digital periapical radiography in diagnosing external and internal inflammatory root resorption after dental trauma and can be considered in the differential diagnosis of resorptive lesions in teeth with endodontic treatment. © 2016 Australian Dental Association.

  2. Morphometric study of the greater palatine canal: cone-beam computed tomography.

    Science.gov (United States)

    Rapado-González, O; Suárez-Quintanilla, J A; Otero-Cepeda, X L; Fernández-Alonso, A; Suárez-Cunqueiro, M M

    2015-12-01

    To analyze greater palatine canal (GPC) dimensions using cone-beam computed tomography (CBCT) images, and to evaluate the position of the greater palatine foramen (GPF) with respect to various landmarks selected in relation to dental status. This study included 150 CBCTs. Axial slices were used to determine the position and dimensions of the GPF. Sagittal slices were used to assess GPC length. Reference lines were established to evaluate the GPC diameter in sagittal and coronal slices. From the 77 GPF analyzed, 76 were located on level 2. Average posterior GPF distance was 6.59 ± 3.27 mm on right side and 7.35 ± 3.40 mm on left side. Several measurements to determine the position and dimensions of the GPF presented significant values (p ≤ 0.05). GPC length was 12.31 ± 1.96 mm on right side and 12.52 ± 2.15 mm on left side, statistically significant differences were detected between genders only on right canal (p ≤ 0.004). Sagittal and coronal reference lines presented significantly higher values for men except for the S3 (p plane and posterior nasal plane are two intraoral anatomical landmarks for the location of the GPF. Their scant variability allows accurate identification of GPFs in both dentate as well as edentulous patients.

  3. Segmentation of cone-beam CT using a hidden Markov random field with informative priors

    Science.gov (United States)

    Moores, M.; Hargrave, C.; Harden, F.; Mengersen, K.

    2014-03-01

    Cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. The rich sources of prior information in IGRT are incorporated into a hidden Markov random field model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk. The voxel labels are estimated using iterated conditional modes. The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom. The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.

  4. Bifid mandibular canal: confirmation of limited cone beam CT findings by gross anatomical and histological investigations

    Science.gov (United States)

    Fukami, K; Shiozaki, K; Mishima, A; Kuribayashi, A; Hamada, Y; Kobayashi, K

    2012-01-01

    Objectives The aims of this study were (1) to assess the validity of limited cone beam CT (CBCT) in detecting the distribution of bifid mandibular canals in the retromolar region by comparing its findings with those of panoramic radiography and spiral CT imaging, and (2) to confirm the contents of such canals depicted on limited CBCT images by using gross anatomical and histological methods. Methods Bilateral bifid mandibular canals of a Japanese cadaver were investigated. The canals depicted on panoramic radiography, spiral CT and limited CBCT images were compared. Cross-sectional limited CBCT images of these canals were compared with gross anatomical sections of the mandible and their contents were confirmed histologically. Results The spiral CT and limited CBCT images showed the bilateral bifid mandibular canals in the retromolar region whereas the panoramic radiographs indicated the presence of only the left bifid mandibular canal. The canal distribution was more distinct in the limited CBCT images than in the spiral CT images and the cross-sectional limited CBCT images were consistent with the gross anatomical sections. Histologically, the canals contained several nerve bundles and arteries among which the largest nerve and artery were of a similar size. Conclusion Limited CBCT is valuable for assessing the distribution of bifid mandibular canals. It is clinically significant to accurately localize a bifid mandibular canal of the retromolar region because it contains a nerve bundle and artery. PMID:22116121

  5. Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification

    Directory of Open Access Journals (Sweden)

    Maria Beatriz Carrazzone Cal ALONSO

    2016-01-01

    Full Text Available Abstract This study aimed at evaluating the validity of cone-beam computed tomography (CBCT for assessing mandibular bone quality using the Klemetti classification. The morphology of the endosteal mandibular cortex of 30 (60 hemi-mandibles postmenopausal women between the ages of 45 and 80 years was evaluated based on the Klemetti classification in panoramic radiographs used as reference images. Afterwards, panoramic reconstruction and cross-sectional slices of CBCT examinations of these patients were analyzed and categorized according to the same classification. All the images were assessed by two oral radiologists. The McNemar-Bowker test compared the agreement between the CBCT images and the reference images. No differences were found between the diagnostic results based on panoramic radiography and panoramic reconstruction. However, the mean scores for the cross-sectional evaluation were higher, and the results, statistically different from the others. Based on the disagreement found between the panoramic radiographs and the CBCT cross-sectional slices, the Klemetti classification is not an adequate means of assessing bone quality with CBCT. On the other hand, the higher values found for the cross-sectional slices could be associated with better visibility on the CBCT images.

  6. Salivary calculus diagnosis with 3-dimensional cone-beam computed tomography.

    Science.gov (United States)

    Dreiseidler, Timo; Ritter, Lutz; Rothamel, Daniel; Neugebauer, Jörg; Scheer, Martin; Mischkowski, Robert A

    2010-07-01

    The objective of this study was to evaluate cone-beam CT (CBCT) diagnoses of sialoliths in the major salivary glands. Twenty-nine CBCT images containing salivary calculi were retrospectively evaluated for image quality and artifact influence. Additionally, the reproducibility of calculus measurement and the differences between CBCT measurements and ultrasonography (US) and histomorphometry (HM) measurements were determined. Diagnostic sensitivity and specificity calculations were based on the observations of 3 masked clinicians, who reviewed a total of 58 CBCT volumes. Salivary calculi were sufficiently visualized in all patients. Metal artifacts were detected in images of 7 patients, and movement artifacts in 2. CBCT calculi measurements were highly reproducible, with mean differences of less than 350 microm. Mean CBCT measurements of calculi diameters differed from mean US measurements by approximately 500 microm and differed from mean HM measurements by approximately 1 mm. For calculus diagnoses, the mean sensitivity and specificity were both 98.85%. Although poor image qualities and artifacts can reduce diagnostic information, salivary calculi can be evaluated adequately with CBCT. CBCT measurements of calculi are highly reproducible and differ little from measurements made with US and HM. Diagnostic sensitivity and specificity levels with CBCT are as high as or higher than those obtained with other diagnostic methods. Because of its high diagnostic-information-to-radiation-dose ratio, CBCT is the preferable imaging modality for salivary calculus diagnosis. Copyright (c) 2010 Mosby, Inc. All rights reserved.

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

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    Darsey, Drew M.; English, Jeryl D.; Ellis, Randy K.; Akyalcin, Sercan [School of Dentistry, University of Texas Health Science Center at Houston, Houston (United States); Kau, Chung H [School of Dentistry, University of Alabama at Birmingham, Birmingham (United States)

    2012-06-15

    The aim of this study was to investigate the initial effects of maxillary expansion therapy with Hyrax appliance and to evaluate the related changes in maxillary sinus volume. Thirty patients (20 females, 10 males; 13.8 years) requiring maxillary expansion therapy, as part of their comprehensive orthodontic treatment, were examined. Each patient had cone-beam computed tomography (CBCT) images taken before (T1) and after (T2) maxillary expansion therapy with a banded Hyrax appliance. Multiplanar slices were used to measure linear dimensions and palatal vault angle. Volumetric analysis was used to measure maxillary sinus volumes. Student t tests were used to compare the pre- and post-treatment measurements. Additionally, differences between two age groups were compared with Mann-Whitney U test. The level of significance was set at p=0.05. Comparison of pre-treatment to post-treatment variables revealed significant changes in the transverse dimension related to both maxillary skeletal and dental structures and palatal vault angle, resulting in a widened palatal vault (p<0.05). Hard palate showed no significant movement in the vertical and anteroposterior planes. Nasal cavity width increased on a mean value of 0.93 mm(SD=0.23, p<0.05). Maxillary sinus volume remained virtually stable. No significant age differences were observed in the sample. Hyrax expansion therapy did not have a significant impact on maxillary sinus volume.

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

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

    2015-10-01

    The high mobility of the bladder and the rectum causes uncertainty in radiation doses prescribed to patients with prostate cancer who undergo radiotherapy (RT) multifraction treatments. The purpose of this study was to estimate the dose received by the bladder, rectum, and prostate from multifraction treatments using daily cone-beam computed tomography (CBCT). Overall, 28 patients with prostate cancer who planned to receive radiation treatments were enrolled in the study. The acquired CBCT before the treatment delivery was registered with the planning CT to map the dose distribution used in the treatment plan for estimating the received dose during clinical treatment. For all 28 patients with 112 data sets, the mean percentage differences (± standard deviation) in the volume and radiation dose were 44% (± 41) and 18% (± 17) for the bladder, 20% (± 21) and 2% (± 2) for the prostate, and 36% (± 29) and 22% (± 15) for the rectum, respectively. Substantial differences between the volumes and radiation dose and those specified in treatment plans were observed. Besides the use of image-guided RT to improve patient setup accuracy, further consideration of large changes in bladder and rectum volumes is strongly suggested when using external beam radiation for prostate cancer.

  9. Dosimetric properties and commissioning of cone-beam CT image beam line with a carbon target

    Energy Technology Data Exchange (ETDEWEB)

    Dzierma, Y. [Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany). Klinik fuer Strahlentherapie und Radioonkologie; Nuesken, F.G.; Licht, N.P.; Ruebe, C. [Universitaetsklinikum des Saarlandes, Homburg/Saar (Germany). Dept. for Radiotherapy

    2013-07-15

    Background and purpose: Accurate patient positioning before radiotherapy is often verified using advanced imaging techniques such as cone-beam computed tomography (CBCT). Even for dedicated imaging beam lines, the applied dose is not necessarily negligible with respect to the treatment dose and should be considered in the treatment plan. Materials and methods: This study presents measurements of the beam properties of the Siemens kView (Siemens AG, Munich, Germany) image beam line (IBL) and the commissioning in the Philips Pinnacle{sup 3} treatment planning system (TPS; Philips, Amsterdam, Netherlands). Results: The percent depth dose curve reaches its maximum at a depth of 10 mm, with a surface dose of 44 %. The IBL operates in flattening filter-free mode, showing the characteristic dose falloff from the central axis. Stability over several days to months is within less than 2 % dose deviation or 1 mm distance-to-agreement. Modelling of the IBL beam line was performed using the Pinnacle{sup 3} automatic modelling routine, with absolute dosimetric verification and film measurements of the fluence distribution. Conclusion: After commissioning of the IBL beam model, the dose from the imaging IBL CBCT can be calculated. Even if the absolute dose deposited is small, repeated imaging doses may sum up to significant amounts and can shift the position of the dose maximum by several centimetres. (orig.)

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

    Science.gov (United States)

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

    2015-01-01

    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. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  11. Cone Beam Computed Tomography Analysis of Incidental Maxillary Sinus Pathologies in North Indian Population

    Directory of Open Access Journals (Sweden)

    Sangeeta S Malik

    2017-01-01

    Full Text Available Introduction: Maxillary sinus can be visualized in both two-dimensional and three-dimensional images. Computed tomography (CT is considered the gold standard method for the examination of maxillary sinus. Cone beam computed tomography (CBCT addresses the limitation of CT and provides many dental advantages. It can provide valuable knowledge about the pathology with limited exposure and low cost compared with other imaging used for diagnostic purposes. Aims and Objectives: The aim of the study is to analyze the prevalence of pathological changes in maxillary sinus of asymptomatic cases using CBCT for diagnostic purposes. Materials and Methods: This retrospective study evaluated 231 patients for incidental maxillary sinus pathologies. Pathological findings were categorized as mucosal thickening, polypoid mucosal thickening, radiopacification, and no pathological findings. Evaluation of pathological findings was done using factors of age and gender. Results: The present study showed 86 cases with maxillary sinus pathology and 145 cases with no pathological findings. Patients with maxillary sinus pathology were mostly diagnosed with mucosal thickening on both sides. In right maxillary sinus, 45 cases (52.3% showed mucosal thickening, and on the left side 36 cases (41.9% were diagnosed with mucosal thickening. Among 86 cases reported, 20 right maxillary sinus (23.3% and 25 left maxillary sinus (29.1% showed no signs of pathology. Conclusion: The incidental maxillary sinus pathologies are highly prevalent in asymptomatic patients. Therefore, oral radiologists should be aware of these incidental findings which will help in early diagnosis and treatment of disease.

  12. Cone-beam micro-CT system based on LabVIEW software.

    Science.gov (United States)

    Ionita, Ciprian N; Hoffmann, Keneth R; Bednarek, Daniel R; Chityala, Ravishankar; Rudin, Stephen

    2008-09-01

    Construction of a cone-beam computed tomography (CBCT) system for laboratory research usually requires integration of different software and hardware components. As a result, building and operating such a complex system require the expertise of researchers with significantly different backgrounds. Additionally, writing flexible code to control the hardware components of a CBCT system combined with designing a friendly graphical user interface (GUI) can be cumbersome and time consuming. An intuitive and flexible program structure, as well as the program GUI for CBCT acquisition, is presented in this note. The program was developed in National Instrument's Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW) graphical language and is designed to control a custom-built CBCT system but has been also used in a standard angiographic suite. The hardware components are commercially available to researchers and are in general provided with software drivers which are LabVIEW compatible. The program structure was designed as a sequential chain. Each step in the chain takes care of one or two hardware commands at a time; the execution of the sequence can be modified according to the CBCT system design. We have scanned and reconstructed over 200 specimens using this interface and present three examples which cover different areas of interest encountered in laboratory research. The resulting 3D data are rendered using a commercial workstation. The program described in this paper is available for use or improvement by other researchers.

  13. Quality control in cone-beam computed tomography (CBCT) EFOMP-ESTRO-IAEA protocol (summary report).

    Science.gov (United States)

    de Las Heras Gala, Hugo; Torresin, Alberto; Dasu, Alexandru; Rampado, Osvaldo; Delis, Harry; Hernández Girón, Irene; Theodorakou, Chrysoula; Andersson, Jonas; Holroyd, John; Nilsson, Mats; Edyvean, Sue; Gershan, Vesna; Hadid-Beurrier, Lama; Hoog, Christopher; Delpon, Gregory; Sancho Kolster, Ismael; Peterlin, Primož; Garayoa Roca, Julia; Caprile, Paola; Zervides, Costas

    2017-07-01

    The aim of the guideline presented in this article is to unify the test parameters for image quality evaluation and radiation output in all types of cone-beam computed tomography (CBCT) systems. The applications of CBCT spread over dental and interventional radiology, guided surgery and radiotherapy. The chosen tests provide the means to objectively evaluate the performance and monitor the constancy of the imaging chain. Experience from all involved associations has been collected to achieve a consensus that is rigorous and helpful for the practice. The guideline recommends to assess image quality in terms of uniformity, geometrical precision, voxel density values (or Hounsfield units where available), noise, low contrast resolution and spatial resolution measurements. These tests usually require the use of a phantom and evaluation software. Radiation output can be determined with a kerma-area product meter attached to the tube case. Alternatively, a solid state dosimeter attached to the flat panel and a simple geometric relationship can be used to calculate the dose to the isocentre. Summary tables including action levels and recommended frequencies for each test, as well as relevant references, are provided. If the radiation output or image quality deviates from expected values, or exceeds documented action levels for a given system, a more in depth system analysis (using conventional tests) and corrective maintenance work may be required. Copyright © 2017. Published by Elsevier Ltd.

  14. Implant treatment planning regarding augmentation procedures: panoramic radiographs vs. cone beam computed tomography images.

    Science.gov (United States)

    Dagassan-Berndt, Dorothea C; Zitzmann, Nicola U; Walter, Clemens; Schulze, Ralf K W

    2016-08-01

    To evaluate the impact of cone beam computed tomography (CBCT) imaging on treatment planning regarding augmentation procedures for implant placement. Panoramic radiographs and CBCT images of 40 patients requesting single-tooth implants in 59 sites were retrospectively analyzed by six specialists in implantology, and treatment planning was performed. Therapeutic recommendations were compared with the surgical protocol performed initially. Bone height estimation from panoramic radiographs yielded to higher measures and greater variability compared to CBCT. The suggested treatment plan for lateral and vertical augmentation procedures based on CBCT or panoramic radiographs coincided for 55-72% of the cases. A trend to a more invasive augmentation procedure was seen when planning was based on CBCT. Panoramic radiography revealed 57-63% (lateral) vs. 67% (vertical augmentation) congruent plans in agreement with surgery. Among the dissenting sites, there was a trend toward less invasive planning for lateral augmentation with panoramic radiographs, while vertical augmentation requirements were more frequently more invasive when based on CBCT. Vertical augmentation requirements can be adequately determined from panoramic radiographs. In difficult cases with a deficient lateral alveolar bone, the augmentation schedule may better be evaluated from CBCT to avoid underestimation, which occurs more frequently when based on panoramic radiographs only. However, overall, radiographic interpretation and diagnostic thinking accuracy seem to be mainly depending on the opinion of observers. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Signs and symptoms after temporomandibular joint washing and cannula placement assessed by cone beam computerized tomography.

    Science.gov (United States)

    Kristensen, Kasper Dahl; Stoustrup, Peter; Alstergren, Per; Küseler, Annelise; Herlin, Troels; Pedersen, Thomas Klit

    2015-08-01

    Analyses of temporomandibular joint synovial fluid using the hydroxocobalamin push-pull technique are increasingly used. However, objective complications and subjective experiences from this procedure have not been described. Firstly, this study aimed to describe discomfort and potential side-effects of this method with special emphasis on symptoms related to the arthrocentesis to be used for future patient information and Ethical Committee applications. Secondly, this study aimed to evaluate the use of cone beam computed tomography (CBCT) as control of intra-capsular cannula placement. Twenty healthy, young adult volunteers were included. Extensive objective and subjective questionnaires were completed before and 14 days after the synovial fluid sampling. With the cannula inside the joints a CBCT was done to investigate if this procedure can be used to verify intra-capsular cannula position. The subjective findings: Most subjects did experience mild pain or discomfort post-operatively. In 12 of 20 subjects symptoms had resolved after 2 days and no subjects had symptoms for more than a week. The longer lasting symptoms were mainly transient joint sounds on mandibular movement. Objective findings: 14 days after the sampling mandibular protrusion had improved 1 mm, but all other objective measures were equal compared to baseline. CBCT showed a large variation in cannula position and no conclusions could be drawn from this. The hydroxocobalamin push-pull synovial fluid sampling may cause minor, transient symptoms. CBCT does not seem to provide any clinical benefits concerning the correct cannula position in relation to the upper joint compartment and disc.

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

    Science.gov (United States)

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

    2015-10-01

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

  17. Upper airway segmentation and dimensions estimation from cone-beam CT image datasets

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Hongjian; Scarfe, W.C. [Louisville Univ., KY (United States). School of Dentistry; Farman, A.G. [Louisville Univ., KY (United States). School of Dentistry; Louisville Univ., KY (United States). Div. of Radiology and Imaging Science

    2006-11-15

    Objective: To segment and measure the upper airway using cone-beam computed tomography (CBCT). This information may be useful as an imaging biomarker in the diagnostic assessment of patients with obstructive sleep apnea and in the planning of any necessary therapy. Methods: With Institutional Review Board Approval, anonymous CBCT datasets from subjects who had been imaged for a variety of conditions unrelated to the airway were evaluated. DICOM images were available. A segmentation algorithm was developed to separate the bounded upper airway and measurements were performed manually to determine the smallest cross-sectional area and the anteriorposterior distance of the retropalatal space (RP-SCA and RP-AP, respectively) and retroglossal space (RG-SCA and RG-AP, respectively). A segmentation algorithm was developed to separate the bounded upper airway and it was applied to determine RP-AP, RG-AP, the smallest transaxial-sectional area (TSCA) and largest sagittal view airway area (LCSA). A second algorithm was created to evaluate the airway volume within this bounded upper airway. Results: Measurements of the airway segmented automatically by the developed algorithm agreed with those obtained using manual segmentation. The corresponding volumes showed only very small differences considered clinically insignificant. Conclusion: Automatic segmentation of the airway imaged using CBCT is feasible and this method can be used to evaluate airway cross-section and volume comparable to measurements extracted using manual segmentation. (orig.)

  18. Cone-beam CT analysis of patients with obstructive sleep apnea compared to normal controls

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, Allison; Kalathingal Sajitha; De Rossi, Scott [Dept. of Oral Health and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta (United States); Cohen, Ruben [Park Avenue Oral and Facial Surgery, New York (United States); Loony, Stephen [Dept. of Biostatistics and Epidemiology, Augusta University Medical College of Georgia, Augusta (United States)

    2016-03-15

    To evaluate the upper airway dimensions of obstructive sleep apnea (OSA) and control subjects using a cone-beam computed tomography (CBCT) unit commonly applied in clinical practice in order to assess airway dimensions in the same fashion as that routinely employed in a clinical setting. This was a retrospective analysis utilizing existing CBCT scans to evaluate the dimensions of the upper airway in OSA and control subjects. The CBCT data of sixteen OSA and sixteen control subjects were compared. The average area, average volume, total volume, and total length of the upper airway were computed. Width and anterior-posterior (AP) measurements were obtained on the smallest axial slice. OSA subjects had a significantly smaller average airway area, average airway volume, total airway volume, and mean airway width. OSA subjects had a significantly larger airway length measurement. The mean A-P distance was not significantly different between groups. OSA subjects have a smaller upper airway compared to controls with the exception of airway length. The lack of a significant difference in the mean A-P distance may indicate that patient position during imaging (upright vs. supine) can affect this measurement. Comparison of this study with a future prospective study design will allow for validation of these results.

  19. Determination of size-specific exposure settings in dental cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Pauwels, Ruben [Chulalongkorn University, Department of Radiology, Faculty of Dentistry, Patumwan, Bangkok (Thailand); University of Leuven, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Jacobs, Reinhilde [University of Leuven, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Bogaerts, Ria [University of Leuven, Laboratory of Experimental Radiotherapy, Department of Oncology, Biomedical Sciences Group, Leuven (Belgium); Bosmans, Hilde [University of Leuven, Medical Physics and Quality Assessment, Department of Imaging and Pathology, Biomedical Sciences Group, Leuven (Belgium); Panmekiate, Soontra [Chulalongkorn University, Department of Radiology, Faculty of Dentistry, Patumwan, Bangkok (Thailand)

    2017-01-15

    To estimate the possible reduction of tube output as a function of head size in dental cone-beam computed tomography (CBCT). A 16 cm PMMA phantom, containing a central and six peripheral columns filled with PMMA, was used to represent an average adult male head. The phantom was scanned using CBCT, with 0-6 peripheral columns having been removed in order to simulate varying head sizes. For five kV settings (70-90 kV), the mAs required to reach a predetermined image noise level was determined, and corresponding radiation doses were derived. Results were expressed as a function of head size, age, and gender, based on growth reference charts. The use of 90 kV consistently resulted in the largest relative dose reduction. A potential mAs reduction ranging from 7 % to 50 % was seen for the different simulated head sizes, showing an exponential relation between head size and mAs. An optimized exposure protocol based on head circumference or age/gender is proposed. A considerable dose reduction, through reduction of the mAs rather than the kV, is possible for small-sized patients in CBCT, including children and females. Size-specific exposure protocols should be clinically implemented. (orig.)

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

    Science.gov (United States)

    Aps, J K M

    2013-06-01

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

  1. Evaluation of Sella Turcica Shape and Dimensions in Cleft Subjects Using Cone-Beam Computed Tomography

    Science.gov (United States)

    Yasa, Yasin; Bayrakdar, Ibrahim Sevki; Ocak, Ali; Duman, Suayip Burak; Dedeoglu, Numan

    2017-01-01

    Objective The aim of this study was to assess the morphology of the sella turcica and measure its size in cleft and noncleft subjects. Material and Methods Cone-beam computed tomography (CBCT) images of 54 individuals (29 males; 25 females) with cleft and 85 (22 males; 63 females) without cleft were used for this study. Syndromic patients with cleft(s) were not included because of possible additional endocrinological and/or morphological disorders. Linear measurements included length, depth, and diameter. The shape of the sella turcica was analyzed in the cleft and noncleft groups. An independent t test was conducted to evaluate differences between genders and groups. One-way ANOVA was used to compare age groups. Results The length (p 25 years in the overall assessment. The distribution of the shape of the sella turcica differed significantly between groups (p < 0.001). Conclusions In this study, CBCT was used to assess the morphology of the sella turcica. A majority of the subjects with cleft had a flattened sella turcica compared to that of the control group. A shorter length of the sella turcica was more evident in the cleft subjects than in the control group. PMID:27855395

  2. Dedicated scanner for laboratory investigations on cone-beam CT/SPECT imaging of the breast

    Energy Technology Data Exchange (ETDEWEB)

    Mettivier, Giovanni, E-mail: mettivier@na.infn.i [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, I-80126 Napoli (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy); Russo, Paolo, E-mail: russo@na.infn.i [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, I-80126 Napoli (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy); Cesarelli, Mario; Ospizio, Roberto [Dipartimento di Ingegneria Biomedica, Elettronica e delle Telecomunicazioni, Universita di Napoli Federico II, I-80125 Napoli (Italy); Passeggio, Giuseppe; Roscilli, Lorenzo; Pontoriere, Giuseppe; Rocco, Raffaele [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, I-80126 Napoli (Italy)

    2011-02-11

    We describe the design, realization and basic tests of a prototype Cone-Beam Breast Computed Tomography (CBBCT) scanner, combined with a SPECT head consisting of a compact pinhole gamma camera based on a photon counting CdTe hybrid pixel detector. The instrument features a 40 {mu}m focal spot X-ray tube, a 50 {mu}m pitch flat panel detector and a 1-mm-thick, 55 {mu}m pitch CdTe pixel detector. Preliminary imaging tests of the separate CT and gamma-ray units are presented showing a resolution in CT of 3.2 mm{sup -1} at a radial distance of 50 mm from the rotation axis and that the 5 and 8 mm hot masses ({sup 99m}Tc labeled with a 15:1 activity ratio with respect to the background) can be detected in planar gamma-ray imaging with a contrast-to-noise ratio of about 4.

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

    Science.gov (United States)

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

    2016-05-01

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

  4. Accurate registration of cone-beam computed tomography scans to 3-dimensional facial photographs.

    Science.gov (United States)

    Nahm, Kyung-Yen; Kim, Yong; Choi, Yong-Suk; Lee, Jeongjin; Kim, Seong-Hun; Nelson, Gerald

    2014-02-01

    Registering a 3-dimensional (3D) facial surface scan to a cone-beam computed tomography (CBCT) scan has various advantages. One major advantage is to compensate for the inaccuracy of the CBCT surface data. However, when registering CBCT and 3D facial scans, changes in facial expression, spatial soft-tissue changes, and differences in the patient's positioning can decrease the accuracy of the registration. In this study, we introduce a new 3D facial scanner that is combined with a CBCT apparatus. Our goal was to evaluate the registration accuracy of CBCT and 3D facial scans, which were taken with the shortest possible time between them. The experiment was performed with 4 subjects. Each patient was instructed to hold as still as possible while the CBCT scan was taken, followed immediately by the 3D facial surface scan. The images were automatically registered with software. The accuracy was measured by determining the degree of agreement between the soft-tissue surfaces of the CBCT and the 3D facial images. The average surface discrepancy between the CBCT facial surface and 3D facial surface was 0.60 mm (SD, 0.12 mm). Registration accuracy was also visually verified by toggling between the images of the CBCT and 3D facial surface scans while rotating the registered images. Registration of consecutively taken CBCT and 3D facial images resulted in reliable accuracy. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  5. [Evaluation of cone-beam CT in diagnosis of supernumerary teeth in the anterior maxilla].

    Science.gov (United States)

    Wen, Chenni; Li, Guo; Ren, Jiayin; Zheng, Guangning

    2012-08-01

    To evaluate the value of cone-beam CT (CBCT) in the diagnosis and orientation of supernumerary teeth in the anterior maxilla. 195 supernumerary teeth in the anterior maxilla of 146 patients were included, which were examined by CBCT. The number, shape, size, 3-dimensional position, growth direction of the supernumeraries and their relationship with the neighboring teeth were analyzed. The 146 patients aged from 5 to 39, and males were affected more than females in a ratio of 2.95:1. 102 (69.9%) patients had single supernumerary teeth. Of the 195 supernumerary teeth, 126 (64.6%) were near the middle line, 131 (67.2%) were conical, 51 (26.2%) were curved root, 98 (50.3%) were inverted and had a length of (11.97 +/- 2.40) mm. The supernumerary teeth often caused complications. The position of the supernumerary teeth is varied in the maxilla, and often causes permanent dentition complications. CBCT imaging yields accurate 3-dimensional pictures of supernumerary teeth, local dental and bony structures, which is helpful for diagnosis and orientation of supernumerary teeth.

  6. Cone beam computed tomography (CBCT) for diagnosis and treatment planning in periodontology: A systematic review.

    Science.gov (United States)

    Walter, Clemens; Schmidt, Julia C; Dula, Karl; Sculean, Anton

    2016-01-01

    The improvement in diagnostic accuracy and optimization of treatment planning in periodontology through the use of three-dimensional imaging with cone beam computed tomography (CBCT) is discussed controversially in the literature. The objective was to identify the best available external evidence for the indications of CBCT for periodontal diagnosis and treatment planning in specific clinical situations. A systematic literature search was performed for articles published by 2 March 2015 using electronic databases and hand search. Two reviewers performed the study selection, data collection, and validity assessment. PICO and PRISMA criteria were applied. From the combined search, seven studies were finally included. The case series were published from the years 2009 to 2014. Five of the included publications refer to maxillary and/or mandibular molars and two to aspects related to vertical bony defects. Two studies show a high accuracy of CBCT in detecting intrabony defect morphology when compared to periapical radiographs. Particularly, in maxillary molars, CBCT provides high accuracy for detecting furcation involvement and morphology of surrounding periodontal tissues. CBCT has demonstrated advantages, when more invasive treatment approaches were considered in terms of decision making and cost benefit. Within their limits, the available data suggest that CBCT may improve diagnostic accuracy and optimize treatment planning in periodontal defects, particularly in maxillary molars with furcation involvement, and that the higher irradiation doses and cost-benefit ratio should be carefully analyzed before using CBCT for periodontal diagnosis and treatment planning.

  7. Absorbed and effective dose from newly developed cone beam computed tomography in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Nyeong; Han, Won Jeong; Kim, Eun Kyung [Dankook Univ. School of Dentistry, Seoul (Korea, Republic of)

    2007-06-15

    Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absolved and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposure. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses.

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

    Science.gov (United States)

    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 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.

  9. Using cone beam computed thomography in planning the extraction of impacted third molars

    Directory of Open Access Journals (Sweden)

    Vlahović Zoran

    2016-01-01

    Full Text Available The panoramic radiography is the most used diagnostic imaging method in planning impacted lower third molar extractions. However, often panoramic radiography does not provide enough information in treatment planning for performing safely surgical extraction of impacted third molars. CBCT (Cone beam computed tomography provides more precise information in diagnostic analysis especially for planning surgical procedures where complications can be expected due to close relationship between mandibular canal and lower impacted third molars. The aim of this study is comparative analysis of panoramic radiography and CBCT in evaluating the topographic relationship between mandibular canal and impacted third molars. The study included 50 patients with close relationship between mandibular canal and impacted third molars detected using panoramic radiography. After panoramic radiography analysis CBCT was performed in order to diagnose, plan and prevent complications during the surgical tooth extraction. CBCT examination considered comparative analysis with panoramic radiography, marking, volume rendering and assessment of mandibular canal in buccolingual direction. Out of total patients where suprimposition of mandibular canal and impacted third molar on panoramic radiography was detected, in 32 patients mandibular chanal was localised on lingual side. Mandibular canal was positioned at bucal side in 18 of 50 patients. Results of this research indicate that panoramic radiography can be useful in everyday practice for diagnosis, planning and preparing lower third molar extractions, but in cases where close relationship between mandibular canal and lower third molars is detected CBCT is recommended as more precise radiographic imaging method in order to prevent complications.

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

    Science.gov (United States)

    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 (pcanal were greater in the bucco-lingual (BL) orientation (30.10°±14.02°) than in the mesio-distal (MD) orientation (14.03°± 8.56°) (pcanal morphology of the mandibular first molars in a Chinese subpopulation. PMID:26241480

  11. A general method for cupping artifact correction of cone-beam breast computed tomography images.

    Science.gov (United States)

    Qu, Xiaolei; Lai, Chao-Jen; Zhong, Yuncheng; Yi, Ying; Shaw, Chris C

    2016-07-01

    Cone-beam breast computed tomography (CBBCT), a promising breast cancer diagnostic technique, has been under investigation for the past decade. However, owing to scattered radiation and beam hardening, CT numbers are not uniform on CBBCT images. This is known as cupping artifact, and it presents an obstacle for threshold-based volume segmentation. In this study, we proposed a general post-reconstruction method for cupping artifact correction. There were four steps in the proposed method. First, three types of local region histogram peaks were calculated: adipose peaks with low CT numbers, glandular peaks with high CT numbers, and unidentified peaks. Second, a linear discriminant analysis classifier, which was trained by identified adipose and glandular peaks, was employed to identify the unidentified peaks as adipose or glandular peaks. Third, adipose background signal profile was fitted according to the adipose peaks using the least squares method. Finally, the adipose background signal profile was subtracted from original image to obtain cupping corrected image In experimental study, standard deviation of adipose tissue CT numbers was obviously reduced and the CT numbers were more uniform after cupping correction by proposed method; in simulation study, root-mean-square errors were significantly reduced for both symmetric and asymmetric cupping artifacts, indicating that the proposed method was effective to both artifacts. A general method without a circularly symmetric assumption was proposed to correct cupping artifacts in CBBCT images for breast. It may be properly applied to images of real patient breasts with natural pendent geometry.

  12. A level set method for cupping artifact correction in cone-beam CT.

    Science.gov (United States)

    Xie, Shipeng; Li, Chunming; Li, Haibo; Ge, Qi

    2015-08-01

    To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts.

  13. Characterization and correction of cupping effect artefacts in cone beam CT

    Science.gov (United States)

    Hunter, AK; McDavid, WD

    2012-01-01

    Objective The purpose of this study was to demonstrate and correct the cupping effect artefact that occurs owing to the presence of beam hardening and scatter radiation during image acquisition in cone beam CT (CBCT). Methods A uniform aluminium cylinder (6061) was used to demonstrate the cupping effect artefact on the Planmeca Promax 3D CBCT unit (Planmeca OY, Helsinki, Finland). The cupping effect was studied using a line profile plot of the grey level values using ImageJ software (National Institutes of Health, Bethesda, MD). A hardware-based correction method using copper pre-filtration was used to address this artefact caused by beam hardening and a software-based subtraction algorithm was used to address scatter contamination. Results The hardware-based correction used to address the effects of beam hardening suppressed the cupping effect artefact but did not eliminate it. The software-based correction used to address the effects of scatter resulted in elimination of the cupping effect artefact. Conclusion Compensating for the presence of beam hardening and scatter radiation improves grey level uniformity in CBCT. PMID:22378754

  14. An energy minimization method for the correction of cupping artifacts in cone-beam CT.

    Science.gov (United States)

    Xie, Shipeng; Zhuang, Wenqin; Li, Haibo

    2016-07-08

    The purpose of this study was to reduce cupping artifacts and improve quantitative accuracy of the images in cone-beam CT (CBCT). An energy minimization method (EMM) is proposed to reduce cupping artifacts in reconstructed image of the CBCT. The cupping artifacts are iteratively optimized by using efficient matrix computations, which are verified to be numerically stable by matrix analysis. Moreover, the energy in our formulation is convex in each of its variables, which brings the robustness of the proposed energy minimization algorithm. The cupping artifacts are estimated as a result of minimizing this energy. The results indicate that proposed algorithm is effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. The proposed method focuses on the reconstructed image without requiring any additional physical equipment; it is easily implemented and provides cupping correction using a single scan acquisition. The experimental results demonstrate that this method can successfully reduce the magnitude of cupping artifacts. The correction algorithm reported here may improve the uniformity of the reconstructed images, thus assisting the development of perfect volume visualization and threshold-based visualization techniques for reconstructed images. © 2016 The Authors.

  15. Cone-Beam computed tomography evaluation of maxillary expansion in twins with cleft lip and palate

    Directory of Open Access Journals (Sweden)

    Luciane Macedo de Menezes

    2012-04-01

    Full Text Available OBJECTIVE: The establishment of normal occlusal relationships in patients with cleft lip and palate using rapid maxillary expansion may promote good conditions for future rehabilitation. OBJECTIVE: This study describes the clinical case of monozygotic twins with unilateral cleft lip and palate at the age of mixed dentition, who were treated using the same rapid maxillary expansion protocol, but with two different screws (conventional and fan-type expansion screw. Results were evaluated using plaster models, intraoral and extraoral photographs, and Cone-Beam computed tomography (CBCT scans obtained before the beginning of the treatment, (T1. METHODS: The patients were followed up for 6 months after maxillary expansion, when the same tests requested at T1 were obtained again for review (T2. T1 and T2 results were compared using lateral cephalometric tracings and measurements of the intercanine and intermolar distances in the plaster models using a digital caliper. RESULTS: The two types of expansion screws corrected the transverse discrepancy in patients with cleft lip and palate. The shape of the upper arches improved at 10 days after activation. CONCLUSION: CBCT scans provide detailed information about craniofacial, maxillary and mandibular changes resulting from rapid maxillary expansion. The most adequate screw for each type of malocclusion should be chosen after detailed examination of the dental arches.

  16. Direct comparison of conventional radiography and cone-beam CT in small bone and joint trauma

    Energy Technology Data Exchange (ETDEWEB)

    Smet, E. de [Antwerp University Hospital, Department of Radiology, Edegem (Belgium); Praeter, G. de [Sint-Maartenziekenhuis, Department of Radiology, Duffel (Belgium); Verstraete, K.L.A. [Ghent University Hospital, Department of Radiology, Ghent (Belgium); Wouters, K. [Antwerp University Hospital, Department of Scientific Coordination and Biostatistics, Edegem (Belgium); Beuckeleer, Luc de [GZA Sint-Augustinus, Department of Radiology, Wilrijk (Belgium); Vanhoenacker, F.M.H.M. [Antwerp University Hospital, Department of Radiology, Edegem (Belgium); Sint-Maartenziekenhuis, Department of Radiology, Duffel (Belgium); Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2015-08-15

    To compare the diagnostic value of cone-beam computed tomography (CBCT) and conventional radiography (CR) after acute small bone or joint trauma. Between March 2013 and January 2014, 231 patients with recent small bone or joint trauma underwent CR and subsequent CBCT. CR and CBCT examinations were independently assessed by two readers, blinded to the result of the other modality. The total number of fractures as well as the number of complex fractures were compared, and inter- and intraobserver agreement for CBCT was calculated. In addition, radiation doses and evaluation times for both modalities were noted and statistically compared. Fracture detection on CBCT increased by 35 % and 37 % for reader 1 and reader 2, respectively, and identification of complex fractures increased by 236 % and 185 %. Interobserver agreement for CBCT was almost perfect, as was intraobserver agreement for reader 1. The intraobserver agreement for reader 2 was substantial. Radiation doses and evaluation time were significantly higher for CBCT. CBCT detects significantly more small bone and joint fractures, in particular complex fractures, than CR. In the majority of cases, the clinical implication of the additionally detected fractures is limited, but in some patients (e.g., fracture-dislocations), the management is significantly influenced by these findings. As the radiation dose for CBCT substantially exceeds that of CR, we suggest adhering to CR as the first-line examination after small bone and joint trauma and keeping CBCT for patients with clinical-radiographic discordance or suspected complex fractures in need of further (preoperative) assessment. (orig.)

  17. Evaluation of cone-beam computed tomography image quality assurance for Vero4DRT system.

    Science.gov (United States)

    Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintarou; Enosaki, Tsubasa; Yamada, Kiyoshi; Nagata, Yasushi

    2017-01-01

    We report the characteristics of quality assurance (QA) image for Vero4DRT system with a kilo-voltage (kV) cone-beam computed tomography (CBCT) capability to perform image-guided radiation therapy (IGRT). To acquire a set of CBCT, the kV source is rotated either 215° clockwise (CW) (tube 1 from 5° to 220° and tube 2 from 275° to 130°) or counterclockwise (CCW) (tube 1 from 85° to 230° and tube 2 from 355° to 140°). Image geometry, image uniformity, high/low contrast resolutions, and contrast linearity were measured with a Catphan 504 CT phantom (The Phantom Laboratory, NY). The comparison between measured and expected distances shows an excellent agreement. The CBCT for Vero4DRT system cannot perform a full 360° rotation, which leads to a loss in uniformity for image acquisition. Separations were observed for high-contrast resolution, with eight line pairs per centimeter corresponding to a gap size of 0.063 cm. For low-contrast resolution, the seventh largest hole was visible. This hole has a 4-mm diameter with 1.0% contrast level. We should check the contrast linearity compared with known value, even though it is out of range from the manufacturer manual.

  18. Development and validation of two phantoms for quality control in cone-beam CT.

    Science.gov (United States)

    Gomes Batista, Wilson Otto

    2017-07-27

    This study aimed at the development and validation of the models of phantom: CQ-02-IFBA and CQ-01-IFBA, the first filled with water and the second fully with a solid structure in polymethylmethacrylate (PMMA). Both models allow its use in various models of cone beam computed tomography (CBCT), independent of the size of the field of view. The two phantoms are used to evaluate seven parameters of quality control: intensity or average value of pixels of five different plastics, signal to noise ratio, resolution, low contrast, spatial resolution, the accuracy of distances on the z axis, the geometric distortion and image uniformity. Spatial resolution is a critical parameter that differs significantly in the various imaging modalities in dental radiology, and in these two phantoms, it can be evaluated by two different methods: MTF obtained by Fourier transformation of the function LSF (line spread function) and/or by analysis visual image to a pattern of bars up to 16 lp/cm. Validation was performed in three models CBCT: CareStream CS 9000 3D, i-CAT Classical and Sirona Orthophos XG 3D. The two phantom models were viable and also complied with the specifications and data available in the literature. It is concluded that the two phantom models are viable for use in CBCT with different characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Evaluation of pathologists (histopathology) and radiologists (cone beam computed tomography) differentiating radicular cysts from granulomas.

    Science.gov (United States)

    Rosenberg, Paul A; Frisbie, Jared; Lee, Jaehoon; Lee, Kyung; Frommer, Herbert; Kottal, Shailesh; Phelan, Joan; Lin, Louis; Fisch, Gene

    2010-03-01

    This study investigated the differentiation of radicular cysts from granulomas. Cone beam computed tomography (CBCT) imaging was compared with the existing standard, biopsy and histopathology. Forty-five patients scheduled for an apicoectomy received a CBCT scan of the involved arch. Two oral and maxillofacial radiologists, working independently and using the same criteria, categorized the CBCT images as one of the following: cyst, likely cyst, likely granuloma, granuloma, or other. After apicoectomies, two oral pathologists, working independently and using the same criteria, diagnosed the surgical specimens as one of the following: radicular cyst, granuloma, or other. We examined the following: (1) interrater agreement between pathologists as to the biopsy diagnosis, (2) interrater agreement between radiologists as to the CBCT diagnosis, and (3) accuracy of radiologists' diagnostic assessments using histopathology as the standard. Findings showed strong interrater reliability between pathologists (kappa=0.79, z=5.46, pradicular cysts from granulomas. Surgical biopsy and histopathological evaluation remain the standard procedure for differentiating radicular cysts from granulomas. Copyright (c) 2010. Published by Elsevier Inc.

  20. The value of cone beam computed tomography in the detection of salivary stones prior to sialendoscopy.

    Science.gov (United States)

    van der Meij, E H; Karagozoglu, K H; de Visscher, J G A M

    2018-02-01

    This study aimed to assess the value of cone beam computed tomography (CBCT) in the detection of salivary stones in patients with signs and symptoms of salivary gland obstruction. A total of 142 major salivary glands were analysed in a cohort of 127 patients with signs and symptoms of salivary gland obstruction. CBCT scans were performed in order to determine the presence of one or more salivary stones. All glands were also investigated by sialendoscopy. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for the submandibular gland, the parotid gland, and the whole group, based on the observers' abilities to diagnose the presence or absence of calculi in the CBCT scan using the sialendoscopy data as the gold standard. Fifty salivary stones were detected in the CBCT scans of the 142 glands analysed: 34 in the submandibular gland and 16 in the parotid gland. The sensitivity (94%), specificity (90%), positive predictive value (84%), and negative predictive value (97%) for the whole group were good to excellent, with an overall accuracy of 92%. CBCT appears to be an ideal first-line imaging modality for patients with signs and symptoms of obstructed major salivary glands. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  1. Cone beam computed tomography-based cephalometric norms for Brazilian adults.

    Science.gov (United States)

    Santos, R M G; De Martino, J M; Haiter Neto, F; Passeri, L A

    2018-01-01

    This study established cone beam computed tomography (CBCT)-based cephalometric norms for Brazilian adults, including the assessment of sexual dimorphism. An observer performed McNamara's cephalometric analysis twice on 60 CBCT datasets acquired from patients with a normal dental occlusion, divided equally into two groups by sex. Welch's t-test was applied to assess differences between the sexes in hard tissue cephalometric measurements, and Dahlberg's formula was used to calculate measurement error introduced by the observer. The cephalometric measurements of effective mandibular length, effective midfacial length, maxillomandibular differential, and lower anterior facial height presented sexual dimorphism. Linear measurements had error ≤0.78mm, and angular measurements had error ≤1.24°. The results show that (1) the CBCT-based cephalometric norms established in this study are reliable for use by researchers and clinicians, and (2) Brazilian adult males and females have similar craniofacial morphology, with males possessing larger jaws than females. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-12-01

    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.

  3. CT to Cone-beam CT Deformable Registration With Simultaneous Intensity Correction

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    Zhen, Xin; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B

    2012-01-01

    Computed tomography (CT) to cone-beam computed tomography (CBCT) deformable image registration (DIR) is a crucial step in adaptive radiation therapy. Current intensity-based registration algorithms, such as demons, may fail in the context of CT-CBCT DIR because of inconsistent intensities between the two modalities. In this paper, we propose a variant of demons, called Deformation with Intensity Simultaneously Corrected (DISC), to deal with CT-CBCT DIR. DISC distinguishes itself from the original demons algorithm by performing an adaptive intensity correction step on the CBCT image at every iteration step of the demons registration. Specifically, the intensity correction of a voxel in CBCT is achieved by matching the first and the second moments of the voxel intensities inside a patch around the voxel with those on the CT image. It is expected that such a strategy can remove artifacts in the CBCT image, as well as ensuring the intensity consistency between the two modalities. DISC is implemented on computer g...

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

    Science.gov (United States)

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

    2017-06-01

    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. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. The Use of Cone Beam Computed Tomography in Assessing the Insertion of Bone Conduction Hearing Implants

    Directory of Open Access Journals (Sweden)

    Tim George Ate Calon

    2017-07-01

    Full Text Available ObjectiveThis 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.MethodsIn 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.ResultsIn 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.ConclusionCBCT 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.

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

    Science.gov (United States)

    Bayram, Mehmet; Kayipmaz, Saadettin; Sezgin, Omer Said; Küçük, Murat

    2012-08-01

    The aim was to determine the accuracy of volumetric analysis of the mandibular condyle using cone-beam computed tomography (CBCT). Five dry mandibles containing 9 condyles were used. CBCT scans of the mandibles and an impression of each condylar area were taken. The physical volumes of the condyles were calculated as the gold standard using the water displacement technique. After isolating, the condylar volume was sectioned in the sagittal plane, and 0.3mm thick sections with 0.9mm intervals were obtained from 3D reconstructions. Using the Cavalieri principle, the volume of each condyle was estimated from the CBCT images by three observers. The accuracy of the CBCT volume measurements and the relation agreements between the results of the three observers were assessed using the Wilcoxon Signed Rank test and Pearson correlation test. The level of statistical significance was set at 0.05. The results of the Pearson correlation showed that there were highly significant positive correlations between the observers' measurements. According to the results of the Wilcoxon Signed Rank test comparing the physical and observers' measurements, there were no statistically significant differences (p>0.05). The Cavalieri principle, used in conjunction with a planimetry method, is a valid and effective method for volume estimation of the mandibular condyle on CBCT images. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  7. Study of the mandibular incisive canal anatomy using cone beam computed tomography.

    Science.gov (United States)

    Kabak, Sergey Lvovich; Zhuravleva, Natallia Victorovna; Melnichenko, Yuliya Michailovna; Savrasova, Nina Alexandrovna

    2017-06-01

    The aim of this study was to identify the range of individual variability in dimensions and topography of the mandibular incisive canal (MIC) in vivo. One hundred cone beam computed tomography (CBCT) scans of patients from dental outpatient hospitals of Minsk, Belarus were performed on Galileos GAX5 using standard exposure and patient positioning protocol. Reformatted panoramic and sagittal CBCT images were analyzed. The MIC was visualized in 92% of CBCT images. It was detected in the first premolar root region in 93% of cases, and only in 21% of cases it reached the central incisors root area. The MIC started prior to the mental foramen opening with formation of the anterior mental loop in 48% of cases. The MIC started at the level of the mental foramen or close to it in 52% of cases. The degree of MIC visibility and its internal vertical diameter decreases when it comes closer to the midline of the mandible. The distance from the roots of teeth to the upper wall of MIC increases in the mesial direction, while the position of MIC in relation to the base of the mandible remains virtually unchanged. The MIC can appear in a different length and can reach the level of the root of the central mandibular incisor. Individual topography of MIC should be determined during the preoperative radiological examination and surgical procedures in the anterior region of the mandible.

  8. Evaluation of location and dimensions of mandibular lingual canals: a cone beam computed tomography study.

    Science.gov (United States)

    Wang, Y-M; Ju, Y-R; Pan, W-L; Chan, C-P

    2015-09-01

    This retrospective study evaluated the presence, location, and diameter of the mandibular lingual canals in a Taiwanese population using cone beam computed tomography (CBCT), to help improve the safety of mandibular surgical procedures. A total of 101 patients (46 men and 55 women), with a mean age of 55 years, were enrolled. Cross-sectional CBCT images of the mandible were used to define the orifice and diameter of each lingual canal detected. The relevance of all data for both sexes was assessed and analyzed statistically using non-paired t-tests. The canals were categorized as median (MLC) and lateral lingual canals (LLC) based on the position of the mandible. The midline of the symphysis showed the highest frequency of lingual canals (97.0%), and all patients exhibited at least one lingual perforating bone canal in the mandible. The lingual canal diameter ranged from 0.25 to 1.90 mm (mean 0.61 mm) in the midline region and from 0.25 to 1.60mm (mean 0.58 mm) in the lateral region. Significant differences in diameter were observed between the sexes in the MLC and LLC groups (men>women). The results suggest that mandibular lingual vascular canals are common and detected regularly using CBCT. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bayram, Mehmet, E-mail: dtmehmetbayram@yahoo.com [Karadeniz Technical University, Faculty of Dentistry, Department of Orthodontics, 61080 Trabzon (Turkey); Kayipmaz, Saadettin; Sezgin, Oemer Said [Karadeniz Technical University, Faculty of Dentistry, Department of Oral Radiology, Trabzon (Turkey); Kuecuek, Murat [Karadeniz Technical University, Faculty of Arts and Sciences, Department of Chemistry, Trabzon (Turkey)

    2012-08-15

    Objective: The aim was to determine the accuracy of volumetric analysis of the mandibular condyle using cone-beam computed tomography (CBCT). Materials and methods: Five dry mandibles containing 9 condyles were used. CBCT scans of the mandibles and an impression of each condylar area were taken. The physical volumes of the condyles were calculated as the gold standard using the water displacement technique. After isolating, the condylar volume was sectioned in the sagittal plane, and 0.3 mm thick sections with 0.9 mm intervals were obtained from 3D reconstructions. Using the Cavalieri principle, the volume of each condyle was estimated from the CBCT images by three observers. The accuracy of the CBCT volume measurements and the relation agreements between the results of the three observers were assessed using the Wilcoxon Signed Rank test and Pearson correlation test. The level of statistical significance was set at 0.05. Results: The results of the Pearson correlation showed that there were highly significant positive correlations between the observers' measurements. According to the results of the Wilcoxon Signed Rank test comparing the physical and observers' measurements, there were no statistically significant differences (p > 0.05). Conclusion: The Cavalieri principle, used in conjunction with a planimetry method, is a valid and effective method for volume estimation of the mandibular condyle on CBCT images.

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

    Science.gov (United States)

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

    2011-01-01

    Cone beam CT (CBCT) has become an increasingly important source of three dimensional (3D) volumetric data in clinical orthodontics since its introduction into dentistry in 1998. The purpose of this manuscript is to highlight the current understanding of, and evidence for, the clinical use of CBCT in orthodontics, and to review the findings to answer clinically relevant questions. Currently available information from studies using CBCT can be organized into five broad categories: 1, the assessment of CBCT technology; 2, its use in craniofacial morphometric analyses; 3, incidental and missed findings; 4, analysis of treatment outcomes; and 5, efficacy of CBCT in diagnosis and treatment planning. The findings in these topical areas are summarized, followed by current indications and protocols for the use of CBCT in specific cases. Despite the increasing popularity of CBCT in orthodontics, and its advantages over routine radiography in specific cases, the effects of information derived from these images in altering diagnosis and treatment decisions has not been demonstrated in several types of cases. It has therefore been recommended that CBCT be used in select cases in which conventional radiography cannot supply satisfactory diagnostic information; these include cleft palate patients, assessment of unerupted tooth position, supernumerary teeth, identification of root resorption and for planning orthognathic surgery. The need to image other types of cases should be made on a case-by-case basis following an assessment of benefits vs risks of scanning in these situations.

  11. A level set method for cupping artifact correction in cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Shipeng; Li, Haibo; Ge, Qi [College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210003 (China); Li, Chunming, E-mail: li-chunming@hotmail.com [School of Electronic Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu, Sichuan 611731 (China)

    2015-08-15

    Purpose: To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). Methods: A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. Results: The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. Conclusions: The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts.

  12. Radiographic assessment of findings in the maxillary sinus using cone-beam computed tomography.

    Science.gov (United States)

    Dobele, Ilze; Kise, Ligija; Apse, Peteris; Kragis, Gints; Bigestans, Andris

    2013-01-01

    OBJECTIVES. To assess the presence of anatomic variations and pathology of the maxillary sinus using cone beam computed tomography (CBCT) of the maxilla where pre- implant surgery is planned. MATERIAL AND METHODS. This retrospective study evaluates a sample CBCT scans of 34 dental patients (68 sinuses). CBCT is used to assess maxillary sinus mucosa and outflow and prevalence of septa. The mucosal thickening was measured and the sinus outflow was classified as open or obstructed. RESULTS. Mucosal thickening was found in 48.5%, septa in 20.6% and total opacity in 2.9% of the sinuses. Maxillary sinus outflow was blocked in 26.5% of the scans. Strong association between radiological signs of maxillary sinus ostium blockage and thickened mucosa was observed. CONCLUSIONS. Anatomic variations and lesions of the maxillary sinus were common findings in CBCT examinations of the maxilla required for dental preprosthetic planning. Routine CBCT scans, including maxillary sinus ostium are recommended for risk assessment prior to surgery.

  13. Maxillofacial trauma patterns associated with external auditory canal fractures: Cone beam computed tomography analysis.

    Science.gov (United States)

    Ali, Ibrahim K; Sansare, Kaustubh; Karjodkar, Freny R; Salve, Prashant; Vanga, Kavita; Pawar, Ajinkya M

    2017-08-01

    There is a paucity of literature on external auditory canal (EAC) fractures secondary to maxillofacial trauma, with most of the literature on EAC fractures consisting of isolated case reports. To the authors' best knowledge, this is the first study to use cone beam computed tomography to evaluate the EAC region. The aim of this study was to assess the prevalence of external auditory canal (EAC) fracture following maxillofacial trauma and to evaluate the association between EAC fracture and other maxillofacial fractures and the region of trauma. One hundred patients were prospectively evaluated over 6 months from February to August 2016. The patients were referred for CBCT regarding temporomandibular joint or condylar fractures following maxillofacial trauma. Two observers (both experienced radiologists) assessed the EAC and associated fractures in the maxillofacial region. External auditory canal (EAC) fracture was confirmed in 32% of the patients. Of the EAC fractures, 68.75% and 31.25% were associated with mandibular fractures and non-mandibular fractures, respectively. Of the EAC fractures, 68.75% were single fractures and 31.25% of patients had multiple comminuted fractures. Significant association was observed on cross-tabulation of the fractured region and region of trauma with the presence of EAC fracture using chi-square test. External auditory canal (EAC) fracture is associated with maxillofacial fractures with increased incidence in mandibular fractures compared to non-mandibular fractures. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

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

    Energy Technology Data Exchange (ETDEWEB)

    Imanimoghaddam, Mahrokh; Mahdavi, Pirooze; Bagherpour, Ali; Darijani, Mansoreh; Ebrahimnejad, Hamed [Dept. of Oral and Maxillofacial Radiology, Oral and Maxillofacial Diseases Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of); Madani, Azam Sadat [Dept. of Oral and Maxillofacial Radiology, Oral and Maxillofacial Diseases Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad (Iran, Islamic Republic of)

    2016-06-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept.of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2015-12-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Santos Pinto de A, E. L.; Manzi, F. R.; Goncalves Z, E. [Pontifical Catholic University of Minas Gerais, Av. Jose Gaspar 500, 30535-901 Belo Horizonte, Minas Gerais (Brazil); Nogueira, M. S.; Fernandes Z, M. A., E-mail: madelon@cdtn.br [Development Center of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: The radiation dose and estimate the radiation induced risk of cancer and morpho functional alterations according to BEIR VII (2006) and recommendations of the ICRP 103 (2007) were measured in cone beam computed tomography (CBCT) scanning (Tc Kodak 9000C 3D) in different oral and maxillofacial regions for diagnosis and planning in implant dentistry for each examination protocol: jaw full, maxilla full and jaw and maxilla full associated. Thermoluminescent dosimeters (TLD- 100 H) were placed in an Alderson-Rando in regions corresponding to the crystalline, parotid, submandibular and thyroid glands and ovaries. The highest values for entrance skin dose were observed in the region of the parotid and submandibular glands, 9.612 mGy to 7.912 mGy and 8.818 mGy to 0.483 mGy, respectively. All examination protocols presented on the right and left sides in the region of the submandibular gland the highest values for absorbed dose (D). In the jaw full exam the thyroid glands on both sides presented highest dose values than maxilla full exam. This study allowed measuring the entrance skin dose and the absorbed dose (D) highlighting a dosimetric preponderance to the salivary glands. With danger of to radiation that induces cancer risk was observed that the age group most likely to have to risk of cancer was 20 years, compared to 30, 40, 50, 60,70 and 80 years. (Author)

  17. Tooth labeling in cone-beam CT using deep convolutional neural network for forensic identification

    Science.gov (United States)

    Miki, Yuma; Muramatsu, Chisako; Hayashi, Tatsuro; Zhou, Xiangrong; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

    2017-03-01

    In large disasters, dental record plays an important role in forensic identification. However, filing dental charts for corpses is not an easy task for general dentists. Moreover, it is laborious and time-consuming work in cases of large scale disasters. We have been investigating a tooth labeling method on dental cone-beam CT images for the purpose of automatic filing of dental charts. In our method, individual tooth in CT images are detected and classified into seven tooth types using deep convolutional neural network. We employed the fully convolutional network using AlexNet architecture for detecting each tooth and applied our previous method using regular AlexNet for classifying the detected teeth into 7 tooth types. From 52 CT volumes obtained by two imaging systems, five images each were randomly selected as test data, and the remaining 42 cases were used as training data. The result showed the tooth detection accuracy of 77.4% with the average false detection of 5.8 per image. The result indicates the potential utility of the proposed method for automatic recording of dental information.

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

    Science.gov (United States)

    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.

  19. Simultaneous calibration phantom commission and geometry calibration in cone beam CT

    Science.gov (United States)

    Xu, Yuan; Yang, Shuai; Ma, Jianhui; Li, Bin; Wu, Shuyu; Qi, Hongliang; Zhou, Linghong

    2017-09-01

    Geometry calibration is a vital step for describing the geometry of a cone beam computed tomography (CBCT) system and is a prerequisite for CBCT reconstruction. In current methods, calibration phantom commission and geometry calibration are divided into two independent tasks. Small errors in ball-bearing (BB) positioning in the phantom-making step will severely degrade the quality of phantom calibration. To solve this problem, we propose an integrated method to simultaneously realize geometry phantom commission and geometry calibration. Instead of assuming the accuracy of the geometry phantom, the integrated method considers BB centers in the phantom as an optimized parameter in the workflow. Specifically, an evaluation phantom and the corresponding evaluation contrast index are used to evaluate geometry artifacts for optimizing the BB coordinates in the geometry phantom. After utilizing particle swarm optimization, the CBCT geometry and BB coordinates in the geometry phantom are calibrated accurately and are then directly used for the next geometry calibration task in other CBCT systems. To evaluate the proposed method, both qualitative and quantitative studies were performed on simulated and realistic CBCT data. The spatial resolution of reconstructed images using dental CBCT can reach up to 15 line pair cm-1. The proposed method is also superior to the Wiesent method in experiments. This paper shows that the proposed method is attractive for simultaneous and accurate geometry phantom commission and geometry calibration.

  20. Detection of periapical bone defects in human jaws using cone beam computed tomography and intraoral radiography.

    Science.gov (United States)

    Patel, S; Dawood, A; Mannocci, F; Wilson, R; Pitt Ford, T

    2009-06-01

    To compare the diagnostic accuracy of intraoral digital periapical radiography with that of cone beam computed tomography (CBCT) for the detection of artificial periapical bone defects in dry human jaws. Small and large artificial periapical lesions were prepared in the periapical region of the distal root of six molar teeth in human mandibles. Scans and radiographs were taken with a charged couple device (CCD) digital radiography system and a CBCT scanner before and after each periapical lesion had been created. Sensitivity, specificity, positive predictive values, negative predictive values and Receiver Operator Characteristic (ROC) curves as well as the reproducibility of each technique were determined. The overall sensitivity was 0.248 and 1.0 for intraoral radiography and CBCT respectively, i.e. these techniques correctly identified periapical lesions in 24.8% and 100% of cases, respectively. Both imaging techniques had specificity values of 1.0. The ROC Az values were 0.791 and 1.000 for intraoral radiography and CBCT, respectively. With intraoral radiography, external factors (i.e. anatomical noise and poor irradiation geometry), which are not in the clinician's control, hinder the detection of periapical lesions. CBCT removes these external factors. In addition, it allows the clinician to select the most relevant views of the area of interest resulting in improved detection of the presence and absence of artificial periapical lesions.

  1. Detection of periodontal bone loss using cone beam CT and intraoral radiography.

    Science.gov (United States)

    de Faria Vasconcelos, K; Evangelista, K M; Rodrigues, C D; Estrela, C; de Sousa, T O; Silva, M A G

    2012-01-01

    The aim of this study was to compare periapical radiographs with cone beam CT (CBCT) imaging in detecting and localizing alveolar bone loss by comparing linear measurements of the height, depth and width of the defects and identifying combined bone defects in tomographic images. The images were selected from a secondary database containing images of patients referred for periodontal evaluation. The sample consisted of 51 sites showing both horizontal and vertical bone loss, assessed by 3 trained examiners. The results showed that there were no statistically significant differences between the imaging methods in terms of identification of the pattern of bone loss. However, there were differences between the two methods when the distance between the cemento-enamel junction (CEJ) and the alveolar crest (AC) was measured. When the distance between the CEJ and the deepest point and width of the defect were measured, the methods showed no statistically significant difference. In this study, 30.8% of the 39 teeth evaluated had combined bone defects. The two methods differ when detecting the height of the alveolar bone crest but present similar views of the depth and width of bone defects. CBCT was the only method that allowed for an analysis of the buccal and lingual/palatal surfaces and an improved visualization of the morphology of the defect.

  2. Detection of dental root fractures by using cone-beam computed tomography.

    Science.gov (United States)

    Wang, P; Yan, X B; Lui, D G; Zhang, W L; Zhang, Y; Ma, X C

    2011-07-01

    The purpose of this study was to compare the diagnostic accuracy of cone beam CT (CBCT) with that of conventional dental radiography in the detection of root fractures and to evaluate the influence of root canal fillings on root fracture detection. We investigated 128 patients with clinically suspected root fractures in 135 teeth. These patients underwent conventional dental radiography, CBCT and eventually surgical exploration. Among the 135 teeth, 86 were non-endodontically treated teeth and 49 were endodontically treated teeth. Two oral radiologists independently analysed the dental radiographs and CBCT images of each patient and reached a consensus. The CBCT findings of root fractures were set as the detection of a separation of the adjacent root segments on at least two contiguous sections and on at least two of the three-dimensional (3D) planes. Root fracture was intraoperatively detected in 95 of the 135 teeth. The sensitivity and specificity of root fractures diagnosed on the basis of the consensus between the 2 evaluators were 26.3% and 100%, respectively, for dental radiography and 89.5% and 97.5%, respectively, for CBCT. CBCT was significantly more accurate than dental radiography in detecting root fractures (P sensitivity of CBCT was reduced in the presence of root canal fillings but its specificity remained unaffected. Both the sensitivity and specificity of dental radiography were not influenced by the presence of root canal fillings. CBCT appears to be more accurate than conventional dental radiography in the detection of root fractures.

  3. [Effectiveness assessment of 3-D cone beam CT used in human bite marks identification].

    Science.gov (United States)

    Wu, Yan; Chen, Xinmin; Shen, Yun; Yu, Jinhao; Tang, Ying; Zhang, Yiming; Zhu, Lei; Xu, Yuanzhi

    2013-02-01

    The present study was aimed to use the 3-D cone beam CT (CBCT) as a new method in human bite marks identification which was carried out in experimental pigskin to assess its effectiveness in our laboratory. Bite marks were digital photographed according to American Board of Forensic Odontology (ABFO) guidelines. In this study, the data of the suspect's dental casts were collected by scanning in two ways: one was after plate scanning, in which the comparison overlays were generated by Adobe Photoshop 8.0 software; the other was by CBCT, which generated comparison overlays automatically. The bite marks were blind identified with the two kinds of data of the suspect's dental casts respectively. ROC curve was used to analyze the sensitivity, specificity, and 95% confidence interval. The results showed that CBCT method got a larger area under the ROC curve: 0.784 (SE = 0.074, 95% CI = 0.639-0.929), and got a very high specificity (specificity 98.7%, 95% CI = 94.5%-99.8%). Thus, this study illustrates that the CBCT used in bite mark identification is an effective and accurate tool and has stronger ability to exclude suspects compared with the conventional method, but the comparison process needs further study to enhance its effectiveness in bite mark identification.

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

    Science.gov (United States)

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

    2012-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Pedroso, Ludmila Assuncao de Mello; Silva, Maria Alves Garcia Santos, E-mail: ludmilapedroso@hotmail.com [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia; Garcia, Robson Rodrigues [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Medicina Oral; Leles, Jose Luiz Rodrigues [Universidade Paulista (UNIP), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Cirurgia; Leles, Claudio Rodrigues [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Fac. de Odontologia. Dept. de Prevencao e Reabilitacao Oral

    2013-11-15

    The aim was to investigate the impact of cone-beam computed tomography (CBCT) on implant planning and on prediction of final implant size. Consecutive patients referred for implant treatment were submitted to clinical examination, panoramic (PAN) radiography and a CBCT exam. Initial planning of implant length and width was assessed based on clinical and PAN exams, and final planning, on CBCT exam to complement diagnosis. The actual dimensions of the implants placed during surgery were compared with those obtained during initial and final planning, using the McNemmar test (p < 0.05). The final sample comprised 95 implants in 27 patients, distributed over the maxilla and mandible. Agreement in implant length was 50.5% between initial and final planning, and correct prediction of the actual implant length was 40.0% and 69.5%, using PAN and CBCT exams, respectively. Agreement in implant width assessment ranged from 69.5% to 73.7%. A paired comparison of the frequency of changes between initial or final planning and implant placement (McNemmar test) showed greater frequency of changes in initial planning for implant length (p < 0.001), but not for implant width (p = 0.850). The frequency of changes was not influenced by implant location at any stage of implant planning (chi-square test, p > 0.05). It was concluded that CBCT improves the ability of predicting the actual implant length and reduces inaccuracy in surgical dental implant planning. (author)

  6. Detection of an unusual inverted schneiderian papilloma by cone beam computed tomography.

    Science.gov (United States)

    Junqueira, Rafael Binato; Almeida, Vinícius Dilly; Grossi, Gustavo Brandão; Sperandio, Jamilly Aparecido; Costa, Lays Kelmer; Verner, Francielle Silvestre

    2017-01-01

    An inverted schneiderian papilloma (ISP) is a rare neoplasm that affects the nasal cavity or a paranasal sinus, especially the maxillary sinus. Although histologically benign, the lesion has a high potential for local destruction, has a high recurrence rate, and presents the possibility of malignant transformation into squamous cell carcinoma. To determine the extent of the injury and possible impairment of adjacent maxillofacial structures, accurate imaging, such as cone beam computed tomography (CBCT), is necessary. A 47-year-old man reported a nasal obstruction on the right side of his face, signs of oroantral communication, and facial asymmetry. The CBCT examination revealed an extensive lesion of mixed density and irregular contours involving the entire right maxillary sinus and nasal cavity. The association between the clinical signs and symptoms and the tomographic features of the lesion resulted in a differential diagnosis of an ISP, which was confirmed through histopathologic examination. This case report confirms that CBCT is a valuable method for the detection of pathologic alterations affecting the maxillary sinus, especially ISPs.

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

    Science.gov (United States)

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

    2016-01-01

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

  8. Dosimetric properties and commissioning of cone-beam CT image beam line with a carbon target.

    Science.gov (United States)

    Dzierma, Y; Nuesken, F G; Licht, N P; Ruebe, C

    2013-07-01

    Accurate patient positioning before radiotherapy is often verified using advanced imaging techniques such as cone-beam computed tomography (CBCT). Even for dedicated imaging beam lines, the applied dose is not necessarily negligible with respect to the treatment dose and should be considered in the treatment plan. This study presents measurements of the beam properties of the Siemens kView (Siemens AG, Munich, Germany) image beam line (IBL) and the commissioning in the Philips Pinnacle(3) treatment planning system (TPS; Philips, Amsterdam, Netherlands). The percent depth dose curve reaches its maximum at a depth of 10 mm, with a surface dose of 44 %. The IBL operates in flattening filter-free mode, showing the characteristic dose falloff from the central axis. Stability over several days to months is within less than 2 % dose deviation or 1 mm distance-to-agreement. Modelling of the IBL beam line was performed using the Pinnacle(3) automatic modelling routine, with absolute dosimetric verification and film measurements of the fluence distribution. After commissioning of the IBL beam model, the dose from the imaging IBL CBCT can be calculated. Even if the absolute dose deposited is small, repeated imaging doses may sum up to significant amounts and can shift the position of the dose maximum by several centimetres.

  9. Detection of Foreign Bodies by Spiral Computed Tomography and Cone Beam Computed Tomography in Maxillofacial Regions

    Directory of Open Access Journals (Sweden)

    Farzaneh Kaviani

    2014-09-01

    Full Text Available Background and aims. The imaging techniques commonly used for foreign body detection include plain radiography, xeroradiography, computed tomography (CT scans, magnetic resonance imaging (MRI and ultrasonography. The aim of the present study was to compare cone-beam computed tomography (CBCT with conventional CT scan in determination of the exact location of a foreign body in the maxillofacial area in vitro. Materials and methods. In this descriptive study, seven different materials were selected as foreign bodies with dimen-sions of approximately 2 mm, 1 mm, and 0.5 mm. These materials consisted of metal, glass, wood, stone, plastic, graphite and tooth. These foreign bodies were placed in a sheep head between the corpus of the mandible and muscle, in the tongue and in an air space. One conventional CT scan and two CBCT scans were made on the models. Results. Tooth, metal, stone and glass foreign bodies were seen clearly on CT and CBCT scans made by NewTom at the smallest size in air. However, CBCT scan by NewTom was a more effective technique for visualization of foreign bodies in air compared to conventional CT. Foreign bodies measuring 0.5 mm made of metal, stone, glass, graphite and teeth were detected by all devices in muscle tissue and adjacent bone. Conclusion. According to the results, CBCT scans of NewTom and Planmeca are appropriate tools for detecting foreign bodies with relative high density in the maxillofacial area.

  10. Equivalent doses for gynecological patients undergoing IMRT or RapidArc with kilovoltage cone beam CT.

    Science.gov (United States)

    Qiu, Yue; Moiseenko, Vitali; Aquino-Parsons, Christina; Duzenli, Cheryl

    2012-08-01

    To investigate in-field and peripheral kilovoltage cone beam CT (CBCT) doses in gynecological patients in comparison with IMRT or RapidArc scatter and linac leakage doses. Monte Carlo codes BEAMnrc/DOSXYZnrc were used to simulate dose for daily use of kV CBCT in patients undergoing adjuvant pelvic radiotherapy for uterine or ovarian malignancies. Biological effectiveness was accounted for using a lineal energy based quality factor. Organ equivalent doses (OED) within the treatment field were modeled with linear-exponential, plateau and linear dose response curves. CBCT doses in peripheral regions were compared with IMRT and RapidArc scatter doses as well as linac leakage doses. CBCT doses in peripheral regions were on the order of linac leakage doses and one order of magnitude lower than IMRT or RapidArc scatter doses. OEDs increased slightly, leveled off or even decreased within the treatment field with the addition of CBCT doses according to different dose response models. The results of this study indicate that patients undergoing IMRT or RapidArc treatments with daily use of kV CBCT imaging are not subjected to additional risk due to CBCT imaging doses. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. A level-set based approach for anterior teeth segmentation in cone beam computed tomography images.

    Science.gov (United States)

    Ji, Dong Xu; Ong, Sim Heng; Foong, Kelvin Weng Chiong

    2014-07-01

    Cone beam CT (CBCT) has gained popularity in dentistry for 3D imaging of the jaw bones and teeth due to its high resolution and relatively lower radiation exposure compared to multi-slice CT (MSCT). However, image segmentation of the tooth from CBCT is more complex than from MSCT due to lower bone signal-to-noise. This paper describes a level-set method to extract tooth shape from CBCT images of the head. We improve the variational level set framework with three novel energy terms: (1) dual intensity distribution models to represent the two regions inside and outside the tooth; (2) a robust shape prior to impose a shape constraint on the contour evolution; and (3) using the thickness of the tooth dentine wall as a constraint to avoid leakage and shrinkage problems in the segmentation process. The proposed method was compared with several existing methods and was shown to give improved segmentation accuracy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Long term three dimensional tracking of orthodontic patients using registered cone beam CT and photogrammetry.

    Science.gov (United States)

    Boulanger, Pierre; Flores-Mir, Carlos; Ramirez, Juan F; Mesa, Elizabeth; Branch, John W

    2009-01-01

    The measurements from registered images obtained from Cone Beam Computed Tomography (CBCT) and a photogrammetric sensor are used to track three-dimensional shape variations of orthodontic patients before and after their treatments. The methodology consists of five main steps: (1) the patient's bone and skin shapes are measured in 3D using the fusion of images from a CBCT and a photogrammetric sensor. (2) The bone shape is extracted from the CBCT data using a standard marching cube algorithm. (3) The bone and skin shape measurements are registered using titanium targets located on the head of the patient. (4) Using a manual segmentation technique the head and lower jaw geometry are extracted separately to deal with jaw motion at the different record visits. (5) Using natural features of the upper head the two datasets are then registered with each other and then compared to evaluate bone, teeth, and skin displacements before and after treatments. This procedure is now used at the University of Alberta orthodontic clinic.

  13. Multimodal registration of three-dimensional maxillodental cone beam CT and photogrammetry data over time.

    Science.gov (United States)

    Bolandzadeh, N; Bischof, W; Flores-Mir, C; Boulanger, P

    2013-01-01

    In recent years, one of the foci of orthodontics has been on systems for the evaluation of treatment results and the tracking of tissue variations over time. This can be accomplished through analysing three-dimensional orthodontic images obtained before and after the treatments. Since complementary information is achieved by integrating multiple imaging modalities, cone beam CT (CBCT) and stereophotogrammetry technologies are used in this study to develop a method for tracking bone, teeth and facial soft-tissue variations over time. We propose a two-phase procedure of multimodal (Phase 1) and multitemporal (Phase 2) registration which aligns images taken from the same patient by different imaging modalities and at different times. Extrinsic (for Phase 1) and intrinsic (for Phase 2) landmark-based registration methods are employed as an initiation for a robust iterative closest points algorithm. Since the mandible moves independently of the upper skull, the registration procedure is applied separately on the mandible and the upper skull. The results show that the signed error distributions of both mandible and skull registrations follow a mixture of two Gaussian distributions, corresponding to alignment errors (due to our method) and temporal change over time. We suggest that the large values among the total registration errors correspond to the temporal change resulting from (1) the effect of treatment (i.e. the orthodontic changes of teeth positions); (2) the biological changes such as teeth growth over time, especially for teenagers; and (3) the segmentation procedure and CBCT precision change over time.

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

    Energy Technology Data Exchange (ETDEWEB)

    Creanga, Adriana Gabriela [Division of Dental Diagnostic Science, Rutgers School of Dental Medicine, Newark (United States); Geha, Hassem; Sankar, Vidya; Mcmahan, Clyde Alex; Noujeim, Marcel [University of Texas Health Science Center San Antonio, San Antonio (United States); Teixeira, Fabrico B. [Dept. of Endodontics, University of Iowa, Iowa City (United States)

    2015-09-15

    The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities. Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement. A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level. CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

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

    Science.gov (United States)

    Mota de Almeida, F J; Knutsson, K; Flygare, L

    2014-01-01

    The aim was to assess to what extent cone beam CT (CBCT) used in accordance with current European Commission guidelines in a normal clinical setting has an impact on therapeutic decisions in a population referred for endodontic problems. The study includes data of consecutively examined patients collected from October 2011 to December 2012. From 2 different endodontic specialist clinics, 57 patients were referred for a CBCT examination using criteria in accordance with current European guidelines. The CBCT examinations were performed using similar equipment and standardized among clinics. After a thorough clinical examination, but before CBCT, the examiner made a preliminary therapy plan which was recorded. After the CBCT examination, the same examiner made a new therapy plan. Therapy plans both before and after the CBCT examination were plotted for 53 patients and 81 teeth. As four patients had incomplete protocols, they were not included in the final analysis. 4% of the patients referred to endodontic clinics during the study period were examined with CBCT. The most frequent reason for referral to CBCT examination was to differentiate pathology from normal anatomy, this was the case in 24 patients (45% of the cases). The primary outcome was therapy plan changes that could be attributed to CBCT examination. There were changes in 28 patients (53%). CBCT has a significant impact on therapeutic decision efficacy in endodontics when used in concordance with the current European Commission guidelines.

  16. Simultaneous calibration phantom commission and geometry calibration in cone beam CT.

    Science.gov (United States)

    Xu, Yuan; Yang, Shuai; Ma, Jianhui; Li, Bin; Wu, Shuyu; Qi, Hongliang; Zhou, Linghong

    2017-08-09

    Geometry calibration is a vital step for describing the geometry of a cone beam computed tomography (CBCT) system and is a prerequisite for CBCT reconstruction. In current methods, calibration phantom commission and geometry calibration are divided into two independent tasks. Small errors in ball-bearing (BB) positioning in the phantom-making step will severely degrade the quality of phantom calibration. To solve this problem, we propose an integrated method to simultaneously realize geometry phantom commission and geometry calibration. Instead of assuming the accuracy of the geometry phantom, the integrated method considers BB centers in the phantom as an optimized parameter in the workflow. Specifically, an evaluation phantom and the corresponding evaluation contrast index are used to evaluate geometry artifacts for optimizing the BB coordinates in the geometry phantom. After utilizing particle swarm optimization, the CBCT geometry and BB coordinates in the geometry phantom are calibrated accurately and are then directly used for the next geometry calibration task in other CBCT systems. To evaluate the proposed method, both qualitative and quantitative studies were performed on simulated and realistic CBCT data. The spatial resolution of reconstructed images using dental CBCT can reach up to 15 line pair cm-1. The proposed method is also superior to the Wiesent method in experiments. This paper shows that the proposed method is attractive for simultaneous and accurate geometry phantom commission and geometry calibration.

  17. Assessment of female breast dose for thoracic cone-beam CT using MOSFET dosimeters.

    Science.gov (United States)

    Sun, Wenzhao; Wang, Bin; Qiu, Bo; Liang, Jian; Xie, Weihao; Deng, Xiaowu; Qi, Zhenyu

    2017-03-21

    To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols and breast sizes were compared. Dose reduction was attempted by using partial arc CBCT scan with bowtie filter. The impact of this dose reduction strategy on image registration accuracy was investigated. The average breast surface doses were 20.02 mGy and 11.65 mGy for thoracic CBCT without filtration and with filtration, respectively. This indicates a dose reduction of 41.8% by use of bowtie filter. It was found 220° partial arc scanning significantly reduced the dose to contralateral breast (44.4% lower than ipsilateral breast), while the image registration accuracy was not compromised. Breast dose reduction can be achieved by using ipsilateral 220° partial arc scan with bowtie filter. This strategy also provides sufficient image quality for thorax image registration in daily patient positioning verification.

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

    Energy Technology Data Exchange (ETDEWEB)

    Egbert, Nicholas [Private Practice, Reconstructive Dental Specialists of Utah, Salt Lake (United States); Cagna, David R.; Ahuja, Swati; Wicks, Russell A. [Dept. of rosthodontics, University of Tennessee Health Science Center College of Dentistry, Memphis (United States)

    2015-03-15

    This study was performed to evaluate the linear distance accuracy and reliability of stitched small field of view (FOV) cone-beam computed tomography (CBCT) reconstructed images for the fabrication of implant surgical guides. Three gutta percha points were fixed on the inferior border of a cadaveric mandible to serve as control reference points. Ten additional gutta percha points, representing fiduciary markers, were scattered on the buccal and lingual cortices at the level of the proposed complete denture flange. A digital caliper was used to measure the distance between the reference points and fiduciary markers, which represented the anatomic linear dimension. The mandible was scanned using small FOV CBCT, and the images were then reconstructed and stitched using the manufacturer's imaging software. The same measurements were then taken with the CBCT software. The anatomic linear dimension measurements and stitched small FOV CBCT measurements were statistically evaluated for linear accuracy. The mean difference between the anatomic linear dimension measurements and the stitched small FOV CBCT measurements was found to be 0.34 mm with a 95% confidence interval of +0.24 - +0.44 mm and a mean standard deviation of 0.30 mm. The difference between the control and the stitched small FOV CBCT measurements was insignificant within the parameters defined by this study. The proven accuracy of stitched small FOV CBCT data sets may allow image-guided fabrication of implant surgical stents from such data sets.

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

    Directory of Open Access Journals (Sweden)

    Farzad Esmaeili

    2012-04-01

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

  20. Use of cone beam CT in children and young people in three United Kingdom dental hospitals.

    Science.gov (United States)

    Hidalgo-Rivas, Jose Alejandro; Theodorakou, Chrysoula; Carmichael, Fiona; Murray, Brenda; Payne, Martin; Horner, Keith

    2014-09-01

    There is limited evidence about the use of cone-beam computed tomography (CBCT) in paediatric dentistry. Appropriate use of CBCT is particularly important because of greater radiation risks in this age group. To survey the use of CBCT in children and young people in three Dental Hospitals in the United Kingdom (UK), with special attention paid to aspects of justification and optimisation. Retrospective analysis of patient records over a 24-month period, looking at CBCT examinations performed on subjects under 18 years of age. Clinical indications, region of interest, scan field of view (FoV), incidental findings and exposure factors used were recorded. There were 294 CBCT examinations performed in this age group, representing 13.7% of all scanned patients. CBCT was used more frequently in the >13 year age group. The most common use was for localisation of unerupted teeth in the anterior maxilla and the detection of root resorption. Optimisation of X-ray exposures did not appear to be consistent. When planning a CBCT service for children and young people, a limited FoV machine would be the appropriate choice for the majority of clinical requirements. It would facilitate clinical evaluation of scans, would limit the number of incidental findings and contribute to optimisation of radiation doses.

  1. The detection accuracies for proximal caries by cone-beam computerized tomography, film, and phosphor plates.

    Science.gov (United States)

    Zhang, Zhi-ling; Qu, Xing-min; Li, Gang; Zhang, Zu-yan; Ma, Xu-chen

    2011-01-01

    To evaluate the accuracy of cone-beam computerized tomography (CBCT) for the detection of noncavitated proximal caries and to compare the detection accuracies of 2 CBCT imaging systems with those based on plain-film radiographs and phosphor-plate images. Test radiographs of 39 noncavitated unrestored human permanent teeth were obtained with film, phosphor-plate, ProMax 3D, and Kodak 9000 3D imaging systems. Seven observers used a 5-level scale to evaluate test images for the presence of proximal caries. With histologic examination serving as the reference standard, observer performances were assessed with receiver operating characteristic (ROC) curves, and the areas under the ROC curves (A(z) values) for the observers, and modalities were analyzed with a repeated-measures analysis of variance. The mean A(z) values for film, phosphor plates, ProMax 3D, and Kodak 9000 3D imaging systems were 0.541, 0.523, 0.528, and 0.525, respectively (P = .763). For detecting subtle noncavitated proximal caries, the detection accuracy with the CBCT images was little better than chance performance and was similar to that with phosphor plate- and film-based intraoral images. Copyright © 2011 Mosby, Inc. All rights reserved.

  2. Cone-beam computed tomography evaluation of dentoskeletal changes after asymmetric rapid maxillary expansion.

    Science.gov (United States)

    Baka, Zeliha Muge; Akin, Mehmet; Ucar, Faruk Izzet; Ileri, Zehra

    2015-01-01

    The aims of this study were to quantitatively evaluate the changes in arch widths and buccolingual inclinations of the posterior teeth after asymmetric rapid maxillary expansion (ARME) and to compare the measurements between the crossbite and the noncrossbite sides with cone-beam computed tomography (CBCT). From our clinic archives, we selected the CBCT records of 30 patients with unilateral skeletal crossbite (13 boys, 14.2 ± 1.3 years old; 17 girls, 13.8 ± 1.3 years old) who underwent ARME treatment. A modified acrylic bonded rapid maxillary expansion appliance including an occlusal locking mechanism was used in all patients. CBCT records had been taken before ARME treatment and after a 3-month retention period. Fourteen angular and 80 linear measurements were taken for the maxilla and the mandible. Frontally clipped CBCT images were used for the evaluation. Paired sample and independent sample t tests were used for statistical comparisons. Comparisons of the before-treatment and after-retention measurements showed that the arch widths and buccolingual inclinations of the posterior teeth increased significantly on the crossbite side of the maxilla and on the noncrossbite side of the mandible (P ARME treatment, the crossbite side of the maxilla and the noncrossbite side of the mandible were more affected than were the opposite sides. Copyright © 2015. Published by Elsevier Inc.

  3. Tomografía computada cone beam en articulación témporo mandibular (ATM

    Directory of Open Access Journals (Sweden)

    DR. B. Andrés Briner

    2014-09-01

    El propósito del presente artículo es exponer imágenes de alta resolución obtenidas mediante la técnica de Cone Beam, mostrando la elevada capacidad que esta técnica tiene para detectar cambios óseos morfológicos sutiles, que permiten el diagnóstico de las diversas etapas del proceso óseo degenerativo.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Soo [School of Dentistry, Chosun University, Gwangju (Korea, Republic of)

    2011-09-15

    Impaction of third molar is a common developmental abnormality. However, ectopic impaction of the mandibular third molar in condylar region is an extremely rare condition. This report describes a case of impacted tooth in the mandibular condyle without any associated pathologic condition. Also, this report presents the spatial relationship of the impacted mandibular third molar to the surrounding anatomic structures using cone beam computed tomography.

  5. Validity and reproducibility of cephalometric measurements performed in full and hemifacial reconstructions derived from cone beam computed tomography

    OpenAIRE

    Ramirez-Sotelo, LR; Almeida, S; Ambrosano, GM; F.; Boscolo

    2012-01-01

    Objective: To test the reproducibility and validity of angular measurements from virtual lateral cephalometric radiography (LCR) reconstructions (full and hemifacial on both sides) derived from cone beam computed tomography (CBCT). Materials and Methods: Fifty-eight CBCT and LCR images were selected. CBCT volume data were imported into Nemotec software, and virtual LCR images and tomographic slices from CBCT images were assessed. Three observers digitized landmarks used for 12 angular measure...

  6. Cone-beam computed tomography analysis of the vestibular surgical pathway to the palatine root of the maxillary first molar

    OpenAIRE

    Kalender, Atakan; Aksoy, Umut; Basmaci, Fatma; Orhan, Kaan; Orhan, Ayse Isil

    2013-01-01

    Objective: The aim of this study was to evaluate the anatomical distance between apices of the palatine root of the maxillary first molars to the buccal bone plate to identify the vestibular surgical pathway in a Turkish adult population using cone-beam computed tomography (CBCT) images. Methods: CBCT scans of 107 (48 male and 59 female) patients were retrospectively analyzed. The overall mean age was 38.6 years. The distance between the vestibular cortex and vestibular side of the palatine r...

  7. An assessment of the maxilla after rapid maxillary expansion using cone beam computed tomography in growing children

    OpenAIRE

    Woller,Jessica L.; Ki Beom Kim; Behrents, Rolf G.; Buschang, Peter H.

    2014-01-01

    INTRODUCTION: With the advent of cone beam computed tomography (CBCT), it is now possible to quantitatively evaluate the effects of rapid maxillary expansion (RME) on the entire maxillary complex in growing patients. OBJECTIVE: The purpose of this study is to use three-dimensional images to evaluate the displacement that occurs at the circummaxillary sutures (frontonasal, zygomaticomaxillary, intermaxillary, midpalatal, and transpalatal sutures) following rapid maxillary expansion in gro...

  8. Palatal bone thickness and associated factors in adult miniscrew placements: A cone-beam computed tomography study

    OpenAIRE

    Poon, Yi-Ching; Chang, Hong-Po; Tseng, Yu-Chuan; Chou, Szu-Ting; Cheng, Jung-Hsuan; Liu, Pao-Hsin; Pan, Chin-Yun

    2015-01-01

    Palatal bone thickness measurements obtained by cone-beam computed tomography (CBCT) in 30 men and 28 women were evaluated for associated factors. Palatal bone thickness was measured at 20 locations unilateral to the midpalatal suture and posterior to the incisive foramen. Tongue position, presence of posterior crossbite, and palatal morphology were recorded. Lateral cephalograms acquired from CBCT data were used to calculate Frankfort-mandibular plane angles (FMA). At almost all sites, bone ...

  9. Upper airway alterations/abnormalities in a case series of obstructive sleep apnea patients identified with cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Shigeta, Y.; Shintaku, W.H.; Clark, G.T. [Orofacial Pain/Oral Medicine Center, Div. of Diagnostic Sciences, School of Dentistry, Univ. of Southern California, Los Angeles, CA (United States); Enciso, R. [Div. of Craniofacial Sciences and Therapeutics, School of Dentistry, Univ. of Southern California, Los Angeles, CA (United States); Ogawa, T. [Dept. of Fixed Prosthodontic Dentistry, Tsurumi Univ., School of Dental Medicine, Tsurumi (Japan)

    2007-06-15

    There are many factors that influence the configuration of the upper airway and may contribute to the development of obstructive sleep apnea (OSA). This paper presents a series of 12 consecutive OSA cases where various upper airway alteration/abnormalities were identified using 3D anatomic reconstructions generated from cone-beam CT (CBCT) images. Some cases exhibited more than one type of abnormality and below we describe each of the six types identified with CBCT in this case series. (orig.)

  10. Maxillary Transverse Comparison of Skeletal Class I and Class III Patient Populations Using Cone Beam Computed Tomography

    Science.gov (United States)

    2012-04-13

    image. Establishing diagnostic problems in this plane can be critical even in the youngest of patients as cessation of the transverse growth comes...Williams CE. Control of the transverse dimension with surgery and orthodontics . Am J Orthod 1980;77:284-306 (NEED) 62     23. Lagravere MO...i     MAXILLARY TRANSVERSE COMPARISON OF SKELETAL CLASS I AND CLASS III PATIENT POPULATIONS USING CONE BEAM COMPUTED TOMOGRAPHY A

  11. Mandibular cortical bone evaluation on cone beam computed tomography images of patients with bisphosphonate-related osteonecrosis of the jaw

    OpenAIRE

    Torres, Sandra R.; Chen, Curtis S. K.; Leroux, Brian G.; Lee, Peggy P.; Hollender, Lars G.; Santos, Eduardo C. A. [UNESP; Drew, Shane P.; Hung, Kuei-Ching; Schubert, Mark M.

    2012-01-01

    Objectives. The objective of this study was to develop a technique for detecting cortical bone dimensional changes in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ).Study Design. Subjects with BRONJ who had cone-beam computed tomography imaging were selected, with age- and gender-matched controls. Mandibular cortical bone measurements to detect bisphosphonate-related cortical bone changes were made inferior to mental foramen, in 3 different ways: within a fixed sized re...

  12. Maxillary First Molars with Six Canals Diagnosed with the Aid of Cone Beam Computed Tomography: A Report of Two Cases

    Directory of Open Access Journals (Sweden)

    Mamta Kaushik

    2013-01-01

    Full Text Available The case reports present the endodontic management of two maxillary first molars with six canals. The diagnosis of morphology of multiple canal systems was identified under magnification of the dental operating microscope and was confirmed with the help of cone beam computed tomography. This paper discusses the variations in the canal morphology and the use of the latest adjuncts in successfully diagnosing and treating unusual canal anatomy.

  13. Cone Beam Computed Tomography Assisted Endodontic Management of a Rare Case of Mandibular First Premolar with Three Roots

    OpenAIRE

    Balakasireddy, K; Kumar, K. Pavan; John, Gijo; Gagan, C

    2015-01-01

    Understanding the morphological anatomy of the root and root canal systems of the teeth increases the success rate of endodontic therapy. Advanced diagnostic imaging techniques like cone beam computed tomography (CBCT) are an essential aid in understanding the anatomy of teeth especially in mandibular premolars. Most commonly mandibular first and second premolars have a single root and a single canal. However, multiple root and canals have also been reported. The present case report discusses...

  14. Identification of dental root canals and their medial line from micro-CT and cone-beam CT records.

    Science.gov (United States)

    Benyó, Balázs

    2012-10-29

    Shape of the dental root canal is highly patient specific. Automated identification methods of the medial line of dental root canals and the reproduction of their 3D shape can be beneficial for planning endodontic interventions as severely curved root canals or multi-rooted teeth may pose treatment challenges. Accurate shape information of the root canals may also be used by manufacturers of endodontic instruments in order to make more efficient clinical tools. Novel image processing procedures dedicated to the automated detection of the medial axis of the root canal from dental micro-CT and cone-beam CT records are developed. For micro-CT, the 3D model of the root canal is built up from several hundred parallel cross sections, using image enhancement, histogram based fuzzy c-means clustering, center point detection in the segmented slice, three dimensional inner surface reconstruction, and potential field driven curve skeleton extraction in three dimensions. Cone-beam CT records are processed with image enhancement filters and fuzzy chain based regional segmentation, followed by the reconstruction of the root canal surface and detecting its skeleton via a mesh contraction algorithm. The proposed medial line identification and root canal detection algorithms are validated on clinical data sets. 25 micro-CT and 36 cone-beam-CT records are used in the validation procedure. The overall success rate of the automatic dental root canal identification was about 92% in both procedures. The algorithms proved to be accurate enough for endodontic therapy planning. Accurate medial line identification and shape detection algorithms of dental root canal have been developed. Different procedures are defined for micro-CT and cone-beam CT records. The automated execution of the subsequent processing steps allows easy application of the algorithms in the dental care. The output data of the image processing procedures is suitable for mathematical modeling of the central line. The

  15. Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR)

    OpenAIRE

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

    2015-01-01

    Total-variation (TV) minimization reconstructions can significantly reduce noise and streaks in thoracic four-dimensional cone-beam computed tomography (4D CBCT) images compared to the Feldkamp-Davis-Kress (FDK) algorithm currently used in practice. TV minimization reconstructions are, however, prone to over-smoothing anatomical details and are also computationally inefficient. The aim of this study is to demonstrate a proof of concept that these disadvantages can be overcome by incorporating...

  16. Identification and Endodontic Management of Middle Mesial Canal in Mandibular Second Molar Using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Bonny Paul

    2015-01-01

    Full Text Available Endodontic treatments are routinely done with the help of radiographs. However, radiographs represent only a two-dimensional image of an object. Failure to identify aberrant anatomy can lead to endodontic failure. This case report presents the use of three-dimensional imaging with cone beam computed tomography (CBCT as an adjunct to digital radiography in identification and management of mandibular second molar with three mesial canals.

  17. The use of a Colapinto TIPS Needle under cone-beam computed tomography guidance for true lumen re-entry in subintimal recanalization of chronic iliac artery occlusion

    Directory of Open Access Journals (Sweden)

    Huei-Lung Liang

    2017-06-01

    Conclusion: The use of Colapinto TIPS needle, especially under cone-beam CT image guidance, appears to be safe and effective to re-enter the true lumen in a subintimal angioplasty for a difficult chronic total iliac occlusion.

  18. The presence of calcifications along the course of internal carotid artery in Greek and Brazilian populations: a comparative and retrospective cone beam CT data analysis

    NARCIS (Netherlands)

    da Silveira, H.L.D.; Damaskos, S.; Arús, N.A.; Tsiklakis, K.; Berkhout, E.W.R.

    2016-01-01

    Objectives. We aimed to retrospectively compare the prevalence of soft tissue calcifications (STCs) depicted incidentally along the extra- and intracranial course of the internal carotid artery (ICA) on cone beam computed tomography examinations in 2 different populations (Greeks and Brazilians).

  19. Cone-Beam Computed Tomography Assessment of Lower Facial Asymmetry in Unilateral Cleft Lip and Palate and Non-Cleft Patients with Class III Skeletal Relationship: e0130235

    National Research Council Canada - National Science Library

    Yifan Lin; Gui Chen; Zhen Fu; Lian Ma; Weiran Li

    2015-01-01

      Introduction To evaluate, using cone-beam computed tomography (CBCT), both the condylar-fossa relationships and the mandibular and condylar asymmetries between unilateral cleft lip and palate (UCLP...

  20. Use of cone-beam CT and live 3-D needle guidance to facilitate percutaneous nephrostomy and nephrolithotripsy access in children and adolescents

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, C.M. [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States); Kukreja, Kamlesh [Texas Children' s Hospital, Department of Radiology, Houston, TX (United States); Singewald, Timothy; Johnson, Neil D.; Racadio, John M. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Minevich, Eugene; Reddy, Pramod [Cincinnati Children' s Hospital Medical Center, Department of Urology, Cincinnati, OH (United States)

    2016-04-15

    Gaining access into non-dilated renal collecting systems for percutaneous nephrolithotripsy, particularly in patients with prohibitive body habitus and/or scoliosis, is often challenging using conventional techniques. To evaluate the feasibility of cone-beam CT for percutaneous nephrostomy placement for subsequent percutaneous nephrolithotripsy in children and adolescents. A retrospective review of percutaneous nephrostomy revealed use of cone-beam CT and 3-D guidance in 12 percutaneous nephrostomy procedures for 9 patients between 2006 and 2015. All cone-beam CT-guided percutaneous nephrostomies were for pre-lithotripsy access and all 12 were placed in non-dilated collecting systems. Technical success was 100%. There were no complications. Cone-beam CT with 3-D guidance is a technically feasible technique for percutaneous nephrostomy in children and adolescents, specifically for nephrolithotripsy access in non-dilated collecting systems. (orig.)

  1. A helical optical for circular polarized UV-FEL project at the UVSOR

    Energy Technology Data Exchange (ETDEWEB)

    Hama, Hiroyuki [Institute for Molecular Science, Okazaki (Japan)

    1995-12-31

    Most of existing storage ring free electron lasers (SRFEL) are restricted those performances by degradation of mirrors in optical cavities. In general, the SRFEL gain at the short wavelength region with high energy electrons is quite low, and the high reflectivity mirrors such as dielectric multilayer mirrors are therefore required. The mirror degradation is considered as a result of irradiation of higher harmonic photons that are simultaneously emitted from planar optical klystron (OK) type undulators, which are commonly used in SRFEL. This problem is getting severer as the lasing wavelength becomes shorter. The UVSOR-FEL had been originally scheduled to be shutdown by 1996 because another undulator project for spectroscopic studies with circular polarized photon would take the FEL`s place. According to suggestion of the insertion device group of the SPring-8, we have designed a helical undulator that is able to vary degree and direction of the polarization easily. In addition, the undulator can be converted into a helical OK by replacing magnets at the center part of undulator in order to coexist with further FEL experiments. Using a calculated magnetic field for magnet configurations of the OK mode, the radiation spectrum at wide wavelength range was simulated by a Fourier transform of Lienard-Wiechert potentials. As a matter of course, some higher harmonics are radiated on the off-axis angle. However it was found out that the higher harmonics is almost negligible as far as inside a solid angle of the Gaussian laser mode. Moreover the gain at the UV region of 250 nm is expected to be much higher than our present FEL because of high brilliant fundamental radiation. The calculated spatial distribution of higher harmonics and the estimated instantaneous gain is presented. Advantages of the helical OK for SRFEL will be discussed in view of our experience, and a possibility of application two-color experiment with SR will be also mentioned.

  2. A practical cone-beam CT scatter correction method with optimized Monte Carlo simulations for image-guided radiation therapy

    Science.gov (United States)

    Xu, Yuan; Bai, Ti; Yan, Hao; Ouyang, Luo; Pompos, Arnold; Wang, Jing; Zhou, Linghong; Jiang, Steve B.; Jia, Xun

    2015-05-01

    Cone-beam CT (CBCT) has become the standard image guidance tool for patient setup in image-guided radiation therapy. However, due to its large illumination field, scattered photons severely degrade its image quality. While kernel-based scatter correction methods have been used routinely in the clinic, it is still desirable to develop Monte Carlo (MC) simulation-based methods due to their accuracy. However, the high computational burden of the MC method has prevented routine clinical application. This paper reports our recent development of a practical method of MC-based scatter estimation and removal for CBCT. In contrast with conventional MC approaches that estimate scatter signals using a scatter-contaminated CBCT image, our method used a planning CT image for MC simulation, which has the advantages of accurate image intensity and absence of image truncation. In our method, the planning CT was first rigidly registered with the CBCT. Scatter signals were then estimated via MC simulation. After scatter signals were removed from the raw CBCT projections, a corrected CBCT image was reconstructed. The entire workflow was implemented on a GPU platform for high computational efficiency. Strategies such as projection denoising, CT image downsampling, and interpolation along the angular direction were employed to further enhance the calculation speed. We studied the impact of key parameters in the workflow on the resulting accuracy and efficiency, based on which the optimal parameter values were determined. Our method was evaluated in numerical simulation, phantom, and real patient cases. In the simulation cases, our method reduced mean HU errors from 44 to 3 HU and from 78 to 9 HU in the full-fan and the half-fan cases, respectively. In both the phantom and the patient cases, image artifacts caused by scatter, such as ring artifacts around the bowtie area, were reduced. With all the techniques employed, we achieved computation time of less than 30 s including the

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

    Science.gov (United States)

    Agarwal, Anirudh; Marwah, Nikhil

    2016-01-01

    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. 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. 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. 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.

  4. Evaluation of the potential of automatic segmentation of the mandibular canal using cone-beam computed tomography.

    Science.gov (United States)

    Gerlach, Nicolaas Lucius; Meijer, Gerrit Jacobus; Kroon, Dirk-Jan; Bronkhorst, Ewald Maria; Bergé, Stefaan Jozef; Maal, Thomas Jan Jaap

    2014-11-01

    We aimed to investigate the effectiveness of software for automatically tracing the mandibular canal on data from cone-beam computed tomography (CT). After the data had been collected from one dentate and one edentate fresh cadaver head, both a trained Active Shape Model (ASM) and an Active Appearance Model (AAM) were used to automatically segment the canals from the mandibular to the mental foramen. Semiautomatic segmentation was also evaluated by providing the models with manual annotations of the foramina. To find out if the tracings were in accordance with the actual anatomy, we compared the position of the automatic mandibular canal segmentations, as displayed on cross-sectional cone-beam CT views, with histological sections of exactly the same region. The significance of differences between results were analysed with the help of Fisher's exact test and Pearson's correlation coefficient. When tracings based on AAM and ASM were used, differences between cone-beam CT and histological measurements varied up to 3.45mm and 4.44mm, respectively. Manual marking of the mandibular and mental foramina did not improve the results, and there were no significant differences (p=0.097) among the methods. The accuracy of automatic segmentation of the mandibular canal by the AAM and ASM methods is inadequate for use in clinical practice. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  5. Cone-Beam Composite-Circling Scan and Exact Image Reconstruction for a Quasi-Short Object

    Directory of Open Access Journals (Sweden)

    Hengyong Yu

    2007-01-01

    Full Text Available Here we propose a cone-beam composite-circling mode to solve the quasi-short object problem, which is to reconstruct a short portion of a long object from longitudinally truncated cone-beam data involving the short object. In contrast to the saddle curve cone-beam scanning, the proposed scanning mode requires that the X-ray focal spot undergoes a circular motion in a plane facing the short object, while the X-ray source is rotated in the gantry main plane. Because of the symmetry of the proposed mechanical rotations and the compatibility with the physiological conditions, this new mode has significant advantages over the saddle curve from perspectives of both engineering implementation and clinical applications. As a feasibility study, a backprojection filtration (BPF algorithm is developed to reconstruct images from data collected along a composite-circling trajectory. The initial simulation results demonstrate the correctness of the proposed exact reconstruction method and the merits of the proposed mode.

  6. Ultrafast and scalable cone-beam CT reconstruction using MapReduce in a cloud computing environment.

    Science.gov (United States)

    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

  7. Small pulmonary nodule localization with cone beam computed tomography during video-assisted thoracic surgery: a feasibility study.

    Science.gov (United States)

    Rouzé, Simon; de Latour, Bertrand; Flécher, Erwan; Guihaire, Julien; Castro, Miguel; Corre, Romain; Haigron, Pascal; Verhoye, Jean-Philippe

    2016-06-01

    To describe a non-invasive guidance procedure, using intraoperative cone beam computed tomography (CBCT) and augmented fluoroscopy to guide lung resection during video-assisted thoracic surgery (VATS). Patients with solitary or multiple lung nodules between 5 and 20 mm in size were included. Under general anaesthesia, a moderate pneumothorax allowing the CBCT acquisition was first performed. Then a segmentation of the lesion was performed on a 3D reconstruction. A projection of this 3D reconstruction was then integrated into the digital workspace and automatically registered into the fluoroscopic images, creating an augmented fluoroscopy. The procedure was continued under classic video-thoracoscopic vision taking account of the augmented fluoroscopy to locate the targeted nodule. Eight patients were included (mean age 61 ± 11.7 years): 7 patients had an isolated lesion and 1 patient had two lesions (mean size 13.2 ± 5.1 mm). Their mean depth to the pleura was 21.4 ± 10.7 mm. Four patients underwent a wedge resection associated with lymph node resection. Two patients had an initial wedge resection followed by a complementary lobectomy associated with lymph node resection (primary lung tumour). One patient had a wedge resection in the upper lobe and a lobectomy of the inferior lobe associated with lymph node resection. One patient underwent a conversion and a bilobectomy due to vascular injury. The mean global operating time was 100.6 ± 36.7 min. All the nodules have been identified on the CBCT acquisitions. The segmentation of the lesion has been performed in all cases. We have been able to detect all the nodules and to successfully perform the resection in all cases owing to the augmented fluoroscopy. The mean fluoroscopic time was 134.2 ± 55.0 s. The mean imaging time, between the incision and the final nodule localization, was 11.8 ± 3.8 min. This paper is the first describing a clinical application of CBCT performed during thoracic surgery. Associated with

  8. Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR)

    Science.gov (United States)

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

    2015-01-01

    Total-variation (TV) minimization reconstructions can significantly reduce noise and streaks in thoracic four-dimensional cone-beam computed tomography (4D CBCT) images compared to the Feldkamp-Davis-Kress (FDK) algorithm currently used in practice. TV minimization reconstructions are, however, prone to over-smoothing anatomical details and are also computationally inefficient. The aim of this study is to demonstrate a proof of concept that these disadvantages can be overcome by incorporating the general knowledge of the thoracic anatomy via anatomy segmentation into the reconstruction. The proposed method, referred as the anatomical-adaptive image regularization (AAIR) method, utilizes the adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS) framework, but introduces an additional anatomy segmentation step in every iteration. The anatomy segmentation information is implemented in the reconstruction using a heuristic approach to adaptively suppress over-smoothing at anatomical structures of interest. The performance of AAIR depends on parameters describing the weighting of the anatomy segmentation prior and segmentation threshold values. A sensitivity study revealed that the reconstruction outcome is not sensitive to these parameters as long as they are chosen within a suitable range. AAIR was validated using a digital phantom and a patient scan and was compared to FDK, ASD-POCS and the prior image constrained compressed sensing (PICCS) method. For the phantom case, AAIR reconstruction was quantitatively shown to be the most accurate as indicated by the mean absolute difference and the structural similarity index. For the patient case, AAIR resulted in the highest signal-to-noise ratio (i.e. the lowest level of noise and streaking) and the highest contrast-to-noise ratios for the tumor and the bony anatomy (i.e. the best visibility of anatomical details). Overall, AAIR was much less prone to over-smoothing anatomical details compared to ASD-POCS and did

  9. Shading correction for on-board cone-beam CT in radiation therapy using planning MDCT images.

    Science.gov (United States)

    Niu, Tianye; Sun, Mingshan; Star-Lack, Josh; Gao, Hewei; Fan, Qiyong; Zhu, Lei

    2010-10-01

    Applications of cone-beam CT (CBCT) to image-guided radiationtherapy (IGRT) are hampered by shading artifacts in the reconstructed images. These artifacts are mainly due to scatter contamination in the projections but also can result from uncorrected beam hardening effects as well as nonlinearities in responses of the amorphous silicon flat panel detectors. While currently, CBCT is mainly used to provide patient geometry information for treatment setup, more demanding applications requiring high-quality CBCT images are under investigation. To tackle these challenges, many CBCT correction algorithms have been proposed; yet, a standard approach still remains unclear. In this work, we propose a shading correction method for CBCT that addresses artifacts from low-frequency projection errors. The method is consistent with the current workflow of radiation therapy. With much smaller inherent scatter signals and more accurate detectors, diagnostic multidetector CT (MDCT) provides high quality CT images that are routinely used for radiation treatment planning. Using the MDCT image as "free" prior information, we first estimate the primary projections in the CBCT scan via forward projection of the spatially registered MDCT data. Since most of the CBCT shading artifacts stem from low-frequency errors in the projections such as scatter, these errors can be accurately estimated by low-pass filtering the difference between the estimated and raw CBCT projections. The error estimates are then subtracted from the raw CBCT projections. Our method is distinct from other published correction methods that use the MDCT image as a prior because it is projection-based and uses limited patient anatomical information from the MDCT image. The merit of CBCT-based treatment monitoring is therefore retained. The proposed method is evaluated using two phantom studies on tabletop systems. On the Catphan 600 phantom, our approach reduces the reconstruction error from 348 Hounsfield unit (HU

  10. Arms Down Cone Beam CT Hepatic Angiography Performance Assessment: Vascular Imaging Quality and Imaging Artifacts.

    Science.gov (United States)

    Gonzalez-Aguirre, Adrian J; Petre, Elena N; Hsu, Meier; Moskowitz, Chaya S; Solomon, Stephen B; Durack, Jeremy C

    2018-01-11

    The practice of positioning patients' arms above the head during catheter-injected hepatic arterial phase cone beam CT (A-CBCT) imaging has been inherited from standard CT imaging due to image quality concerns, but interrupts workflow and extends procedure time. We sought to assess A-CBCT image quality and artifacts with arms extended above the head versus down by the side. We performed an IRB approved retrospective evaluation of reformatted and 3D-volume rendered images from 91 consecutive A-CBCTs (43 arms up, 48 arms down) acquired during hepatic tumor arterial embolization procedures. Two interventional radiologists reviewed all A-CBCT imaging and assigned vessel visualization scores (VVS) from 1 to 5, ranging from non-diagnostic to optimal visualization. Streak artifacts across axial images were rated from 1 to 3 based on resulting image quality (none to significant). Presence of respiratory or cardiac motion during acquisition, body mass index and radiation dose area product (DAP) were also recorded and analyzed. Univariate and multivariate analyses were used to assess the impact of arm position on VVS and imaging artifacts. VVS were not significantly associated with arm position during A-CBCT imaging. One reader reported more streak artifacts across axial images in the arms down group (p = 0.005). DAP was not statistically different between the groups (23.9 Gy cm2 [6.1-73.4] arms up, 26.1 Gy cm2 [4.2-102.6] arms down, p = 0.54). A-CBCT angiography performed with the arms above the head is not superior for clinically relevant hepatic vascular visualization compared to imaging performed with the arms by the patient's side.

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

    Directory of Open Access Journals (Sweden)

    Cristina Bucchi

    2016-02-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2016-02-21

    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.

  13. Is Cone-Beam Computed Tomography Always Necessary for Dental Implant Placement?

    Science.gov (United States)

    Deeb, George; Antonos, Ludmils; Tack, Samuel; Carrico, Caroline; Laskin, Daniel; Deeb, Janina Golob

    2017-02-01

    The use of cone-beam computed tomography (CBCT) for evaluation of patients for dental implants has gained considerable popularity. This retrospective cohort study was designed to determine whether using a clinical examination and a panoramic radiograph (Panorex) for implant selection and determining the need for bone grafting would be comparable to using CBCT in routine implant cases. Implant size and need for bone grafting were initially determined in 82 patients using a panoramic radiograph and clinical examination. These patients subsequently underwent CBCT and their treatment was re-planned by the same surgeon using Simplant treatment planning software (DENTSPLY Implants, Mölndal, Sweden) in addition to clinical examination. The length and width of implants selected by each method and the need for bone grafting were recorded and the results were compared statistically with each other and with the actual treatment subsequently rendered. The Panorex method and the CBCT method accurately predicted implant width to within 1.5 mm of the implant actually placed in 100% of cases and length to within 1.5 mm in more than 95% of cases. For bone graft prediction, the results indicated that neither the Panorex method nor CBCT method differed substantially from the actual treatment rendered. The results of this study indicate that the CBCT is more accurate in predicting implant length and width and the need for bone grafting procedures. However, for routine unguided implant placement in sites where anatomic structures and bone grafting are not a concern, the use of a panoramic radiograph could be adequate for determining the length and width of the implant. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Clinical Application of Cone-Beam Computed Tomography of the Rabbit Head: Part 1 - Normal Dentition

    Directory of Open Access Journals (Sweden)

    GG Comet Riggs

    2016-10-01

    Full Text Available Domestic rabbits (Oryctolagus cuniculus are increasingly popular as household pets; therefore, veterinarians need to be familiar with the most common diseases afflicting rabbits including dental diseases. Diagnostic approaches for dental disease include gross oral examination, endoscopic oral examination, skull radiography, and computed tomography (CT. CT overcomes many limitations of standard radiography by permitting cross-sectional images of the rabbit head in multiple planes without superimposition of anatomic structures. Cone-beam CT (CBCT is an oral and maxillofacial imaging modality that produces high-resolution images. The objective of this study was to describe and compare the normal anatomic features of the dentition and surrounding maxillofacial structures in healthy rabbits on CBCT and conventional CT. Ten New Zealand white rabbit cadaver heads were scanned using CBCT and conventional CT. Images were evaluated using Anatomage Invivo 5 software. The maxillofacial anatomy was labeled on CBCT images and the mean lengths and widths of the teeth were determined. The visibility of relevant dental and anatomic features (pulp cavity, germinal center, tooth outline, periodontal ligament were scored and compared between conventional CT and CBCT. The thinnest teeth were the maxillary second incisor teeth at 1.29 ± 0.26 mm and the maxillary third molar teeth at 1.04 ±0.10 mm. In general, it was found that CBCT was superior to conventional CT when imaging the dentition. Importantly, the periodontal ligament was significantly (P<0.01 more visible on CBCT than on conventional CT. Ability to see the periodontal ligament with such detail may allow earlier detection and treatment of periodontal disease in rabbits. This study is the first of its kind and shows the feasibility and yield of CBCT when evaluating the maxillofacial features and dentition in rabbits.

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

    Science.gov (United States)

    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 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.

  16. Accuracy of cone-beam computed tomography and periapical radiography in detecting small periapical lesions.

    Science.gov (United States)

    Tsai, Patrick; Torabinejad, Mahmoud; Rice, Dwight; Azevedo, Bruno

    2012-07-01

    The aim of this study was to determine the diagnostic accuracy of 2 cone-beam computed tomography (CBCT) machines and periapical (PA) radiography in detecting simulated apical lesions created with the smallest dental burs available. By using mandibles from human cadavers, simulated apical lesions were created and then progressively enlarged in 16 roots by using sizes #1/4, #1/2, #1, #2, #4, and #6 round burs. Imaging was obtained after each enlargement with a Kodak 9000 3D (Kodak) CBCT, a Veraviewpocs 3De (Morita) CBCT, and intraoral digital PA radiography. Specificity and sensitivity at variable decision thresholds were calculated and plotted on receiver operator characteristic curves. The area under the curve (AUC) served as an estimate of diagnostic accuracy. The overall AUCs for Kodak, Morita, and PA radiography were 0.767 (95% confidence interval [CI], 0.743-0.792), 0.753 (95% CI, 0.728-0.779), and 0.584 (95% CI, 0.554-0.615), respectively. The AUCs for Kodak and Morita were both statistically significantly larger than the AUC for all corresponding simulated lesion sizes imaged with PA radiography. Between Kodak and Morita, there were no statistically significant differences in AUCs for any of the corresponding simulated lesion sizes. Both CBCT devices demonstrated poor accuracy in detecting simulated lesions smaller than 0.8 mm in diameter, fair to good accuracy when simulated lesion diameter was between 0.8-1.4 mm, and excellent accuracy when simulated lesions were larger than 1.4 mm in diameter. PA radiography, at best, demonstrated poor diagnostic accuracy for all simulated lesion sizes. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-15

    To compare and evaluate the diagnostic ability of cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). CBCT and MRI of 46 TMJs of 23 patients with TMJ disorders were evaluated. They were divided into 3 groups according to the position of the articular disc of the TMJ at closed mouth position and the reduction of the disc during open mouth position on MRI: no disc displacement group (NDD), disc displacement with reduction group (DDR), and disc displacement without reduction group (DDWR). With PACS viewing software, position of mandibular condyle in the articular fossa, osseous change of mandibular condyle, shape of articular fossa, and mediolateral and anteroposterior dimensions of mandibular condyle were evaluated on CBCT and MRI. Each value was tested statistically. The position of mandibular condyle in the articular fossa were concentric in the NDD, DDR, and DDWR of CBCT and NDD of MRI. However, condyle was positioned posteriorly in DDR and DDWR of MRI. Flattening, sclerosis and osteophyte of the mandibular condyle were much more apparent on DDR of CBCT than MRI. And the erosion of the condyle was much more apparent on DDWR of MRI than CBCT. Box and Sigmoid types of articular fossa were found most frequently in DDR of MRI. Flattened type was found most frequently in DDR of CBCT and deformed type was found most frequently in DDWR of CBCT. No significant difference in mediolateral and anteroposterior dimensions were shown on CBCT and MRI. Since MRI and CBCT has unique diagnostic imaging ability, both modalities should be used together to supplement each other to evaluate TMJ.

  18. COMPARISON OF CONE-BEAM COMPUTED TOMOGRAPHY AND PANORAMIC RADIOGRAPHS IN DETECTING MAXILLARY SINUS SEPTA

    Directory of Open Access Journals (Sweden)

    Meryem TORAMAN-ALKURT

    2016-10-01

    Full Text Available Purpose: The purpose of this retrospective study was to compare the performance of cone-beam computed tomography (CBCT and panoramic radiography in detecting the presence and location of maxillary sinus septa. Materials and methods: This study included radiographic examination of 104 maxillary sinuses of 52 individuals (26 females, 50% and 26 males, 50% whose panoramic radiographs and CBCT images were obtained for several dental causes which were examined by the consensus of four dentomaxillofacial radiologists. The posterior maxillary segments in proximity of maxillary sinus were classified as edentulous and dentate maxillary segments. The location of maxillary sinus septa was classified as primary septa and secondary septa according to the presence of maxillary tooth at the affected site. The maxillary sinus septa were divided into three categories (anterior, middle and posterior according to its relation with posterior maxillary teeth. Data were statistically analyzed with chi-square and Fisher’s exact tests. Results: The septa were found in 23.1% and 29.8% of the maxillary sinuses on panoramic radiography and CBCT images, respectively. The majority of maxillary sinus septa were observed in dentate posterior maxillary segments on both panoramic (45.8% radiography and CBCT (64.5% images. Statistically significant differences (p<0.001 were found between panoramic radiography and CBCT images for presence, location and neighborhood with the posterior maxillary teeth of maxillary sinus septa. Conclusion: The results of this study demonstrated the low reliability of panoramic radiography images in the detection of maxillary sinus septa. CBCT images can provide valuable information to the clinicians about the presence and location of maxillary sinus septa.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-15

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

  1. Radiation dose saving through the use of cone-beam CT in hearing-impaired patients.

    Science.gov (United States)

    Faccioli, N; Barillari, M; Guariglia, S; Zivelonghi, E; Rizzotti, A; Cerini, R; Mucelli, R Pozzi

    2009-12-01

    Bionic ear implants provide a solution for deafness. Patients treated with these hearing devices are often children who require close follow-up with frequent functional and radiological examinations; in particular, multislice computed tomography (MSCT). Dental volumetric cone-beam CT (CBCT) has been reported as a reliable technique for acquiring images of the temporal bone while delivering low radiation doses and containing costs. The aim of this study was to assess, in terms of radiation dose and image quality, the possibility of using CBCT as an alternative to MSCT in patients with bionic ear implants. One hundred patients (mean age 26 years, range 7-43) with Vibrant SoundBridge implants on the round window underwent follow-up: 85 with CBCT and 15 with MSCT. We measured the average tissue-absorbed doses during both MSCT and CBCT scans. Each scan was focused on the temporal bone with the smallest field of view and a low-dose protocol. In order to estimate image quality, we obtained data about slice thickness, high- and low-contrast resolution, uniformity and noise by using an AAPM CT performance phantom. Although the CBCT images were qualitatively inferior to those of MSCT, they were sufficiently diagnostic to allow evaluation of the position of the implants. The effective dose of MSCT was almost three times higher than that of CBCT. Owing to low radiation dose and sufficient image quality, CBCT could be considered an adequate technique for postoperative imaging and follow-up of patients with bionic ear implants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-15

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

  3. Image quality of a cone beam O-arm 3D imaging system

    Science.gov (United States)

    Zhang, Jie; Weir, Victor; Lin, Jingying; Hsiung, Hsiang; Ritenour, E. Russell

    2009-02-01

    The O-arm is a cone beam imaging system designed primarily to support orthopedic surgery and is also used for image-guided and vascular surgery. Using a gantry that can be opened or closed, the O-arm can function as a 2-dimensional (2D) fluoroscopy device or collect 3-dimensional (3D) volumetric imaging data like a CT system. Clinical applications of the O-arm in spine surgical procedures, assessment of pedicle screw position, and kyphoplasty procedures show that the O-arm 3D mode provides enhanced imaging information compared to radiographs or fluoroscopy alone. In this study, the image quality of an O-arm system was quantitatively evaluated. A 20 cm diameter CATPHAN 424 phantom was scanned using the pre-programmed head protocols: small/medium (120 kVp, 100 mAs), large (120 kVp, 128 mAs), and extra-large (120 kVp, 160 mAs) in 3D mode. High resolution reconstruction mode (512×512×0.83 mm) was used to reconstruct images for the analysis of low and high contrast resolution, and noise power spectrum. MTF was measured using the point spread function. The results show that the O-arm image is uniform but with a noise pattern which cannot be removed by simply increasing the mAs. The high contrast resolution of the O-arm system was approximately 9 lp/cm. The system has a 10% MTF at 0.45 mm. The low-contrast resolution cannot be decided due to the noise pattern. For surgery where locations of a structure are emphasized over a survey of all image details, the image quality of the O-arm is well accepted clinically.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tehranchi, Maryam; Taleghani, Ferial; Shahab, Shahriar [Faculty of Dentistry, Shahed University, Tehran (Iran, Islamic Republic of); Nouri, Arash [Nouri' s Dental Clinic, Tehran (Iran, Islamic Republic of)

    2017-03-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xin, E-mail: Xin.Liang@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); College of Stomatology, Dalian Medical University (China); Jacobs, Reinhilde, E-mail: Reinhilde.Jacobs@uz.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Hassan, Bassam, E-mail: b.hassan@acta.n [Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); Li Limin, E-mail: Limin.Li@uz.kuleuven.b [Department of Paediatric Dentistry and Special Dental Care, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Pauwels, Ruben, E-mail: Ruben.Pauwels@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Corpas, Livia, E-mail: LiviaCorpas@gmail.co [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Souza, Paulo Couto, E-mail: Paulo.CoutoSouza@med.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Martens, Wendy, E-mail: wendy.martens@uhasselt.b [Department of Basic Medical Sciences, Faculty of Medicine, University of Hasselt, Diepenbeek (Belgium); Shahbazian, Maryam, E-mail: Maryam.Shahbazian@student.kuleuven.b [Oral Imaging Centre, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven (Belgium); Alonso, Arie, E-mail: ariel.alonso@uhasselt.b [Department of Biostatistics and Statistical Bioinformatics, Universiteit Hasselt (Belgium)

    2010-08-15

    Aims: To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system. Materials and methods: One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale. Results: Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p = 0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p = 0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise. Conclusions: CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.

  6. Cone-beam computed tomography in pediatric dentistry, a retrospective observational study.

    Science.gov (United States)

    Van Acker, Jakob W G; Martens, Luc C; Aps, Johan K M

    2016-06-01

    The aim of this study was to find the reasons for referral and their correlation with age, gender, field of view, and resolution for all patients under the age of 18 who underwent a cone-beam computed tomography (CBCT) scan between 1 May 2010 and 1 May 2012 in the dental out-patient clinic of the University Hospital Ghent. From the local CBCT database, 79 pediatric patients gave their consent. Subsequently age, gender, reason for referral, external or internal referral, field of view (FOV), and resolution data were collected. Descriptive and comparative statistical analysis was performed. There seemed to be a correlation between orthodontic referrals and female patients. The majority of patients referred for trauma follow-up were 12 years and older. Fourteen percent of referrals were for dento-alveolar trauma, 18 % for other dento-alveolar reasons, 4 % for developing dentition-generalized, 36 % for developing dentition-localized, 10 % for endodontics, 1 % for periodontics, 16 % for surgical applications, and 1 % was for the visualization of the TMJ. Eighty percent of the CBCTs were taken at a FOV 50 × 55 mm. Larger FOV was used for surgical planning or follow-up reasons. The majority of the CBCTs was taken at a resolution of 200 μm, while a resolution of 150 μm was used for endodontic issues. From these results, a classification system for referral was developed. From the present study, it can be concluded that a referral pattern could be detected which was correlated with gender, age group, FOV, and resolution. These results can help practitioners make the decision to refer for CBCT when extra three dimensional imaging is expected to have a benefit in therapeutic value for a pediatric or adolescent patient. This study can guide dental professionals referring pediatric and adolescent patients for CBCT.

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

    Science.gov (United States)

    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

  8. Cemento-Osseous Dysplasias: Imaging Features Based on Cone Beam Computed Tomography Scans.

    Science.gov (United States)

    Cavalcanti, Paulo Henrique Pereira; Nascimento, Eduarda Helena Leandro; Pontual, Maria Luiza Dos Anjos; Pontual, Andréa Dos Anjos; Marcelos, Priscylla Gonçalves Correia Leite de; Perez, Danyel Elias da Cruz; Ramos-Perez, Flávia Maria de Moraes

    2018-01-01

    Imaging exams have important role in diagnosis of cemento-osseous dysplasia (COD). Cone beam computed tomography (CBCT) stands out for allowing three-dimensional image evaluation. This study aimed to assess the prevalence of cases diagnosed as COD on CBCT scans, as well identify the main imaging features related to these lesions. An analysis was performed in a database containing 22,400 radiological reports, in which all cases showing some type of COD were initially selected. These CBCT exams were reevaluated to confirm the radiographic diagnosis and determine the prevalence and distribution of the types of COD with regard to gender, age and preferred location, while describing its most common imaging aspects. Data were presented using descriptive analyses. There were 82 cases diagnosed as COD in the CBCT images (prevalence of 0.4%). The distribution of patients was 11 (13.4%) male and 71 (86.6%) female, with a mean age of 49.8 years (age-range 17-85 years). There were 47 (57.3%) cases of periapical COD, 23 (28%) of focal COD and 12 (14.6%) of florid COD. The mandible was more affected than the maxilla. In most cases, the lesions were mixed or hyperdense. All COD had well-defined limits and there were no cases of tooth displacement. In conclusion, periapical COD was the most common type and the most affected bone was the mandible. Imaging evaluation is critical for diagnosis and dentists should bear in mind all possible radiographic presentations of COD in order to prevent misleading diagnoses and consequently, inadequate treatments.

  9. Investigation of impacted supernumerary teeth: a cone beam computed tomograph (cbct) study.

    Science.gov (United States)

    Gurler, Gokhan; Delilbasi, Cagri; Delilbasi, Evren

    2017-01-01

    The purpose of this study was to investigate the impacted supernumerary teeth which were initially detected on panoramic radiographs by using cone beam computed tomography (CBCT). In this retrospective study, supernumerary teeth diagnosed on panoramic radiographs taken from patients who had admitted for routine dental treatment were evaluated using CBCT. Patients' age, gender, systemic conditions as well as number of supernumerary teeth, unilateral-bilateral presence, anatomical localization (maxilla, mandible, anterior-premolar-molar, mesiodens-lateral-canine, parapremolar-paramolar-distomolar) shape (rudimentary, supplemental, tuberculate, odontoma), position (palatal-lingual-buccal-labial-central), shortest distance between the tooth and adjacent cortical plate, complications and treatment were assessed. A total of 47 impacted supernumerary teeth in 34 patients were investigated in this study. Of these, 33 (70.2%) were unilateral and 14 (29.8%) were bilateral. Only 1 supernumerary tooth was found in 27 patients (79.4%) whereas 7 patients (20.6%) had 2 or more supernumerary teeth. Most of the teeth located in the anterior region (74.4%) of the jaws and maxilla (74.4%). Twenty teeth (42.5%) were mesiodens, 11 (23.4%) were lateral or canine, 14 (29.7%) were parapremolar and 2(4.4%) were distomolar. Twenty-seven teeth (57.4%) were rudimentary, 15 (31.9%) were supplemental and 5 (10.7%) were odontoma in shape. The shortest distance between the supernumerary tooth and adjacent cortical plate varied between 0 to 2.5 mm with a mean of 0.66 mm. The most common clinical complaint was the non-eruption of permanent teeth (42.5%). All supernumerary teeth were removed under local anesthesia. Orthodontic traction was performed for those impacted permanent teeth if necessary. Impacted supernumerary teeth are usually in close proximity to cortical bone. Although this may facilitate surgical access, there is a risk of damaging surrounding anatomical structures. Therefore, CBCT

  10. How accurate are the fusion of cone-beam CT and 3-D stereophotographic images?

    Directory of Open Access Journals (Sweden)

    Yasas S N Jayaratne

    Full Text Available BACKGROUND: Cone-beam Computed Tomography (CBCT and stereophotography are two of the latest imaging modalities available for three-dimensional (3-D visualization of craniofacial structures. However, CBCT provides only limited information on surface texture. This can be overcome by combining the bone images derived from CBCT with 3-D photographs. The objectives of this study were 1 to evaluate the feasibility of integrating 3-D Photos and CBCT images 2 to assess degree of error that may occur during the above processes and 3 to identify facial regions that would be most appropriate for 3-D image registration. METHODOLOGY: CBCT scans and stereophotographic images from 29 patients were used for this study. Two 3-D images corresponding to the skin and bone were extracted from the CBCT data. The 3-D photo was superimposed on the CBCT skin image using relatively immobile areas of the face as a reference. 3-D colour maps were used to assess the accuracy of superimposition were distance differences between the CBCT and 3-D photo were recorded as the signed average and the Root Mean Square (RMS error. PRINCIPAL FINDINGS: The signed average and RMS of the distance differences between the registered surfaces were -0.018 (±0.129 mm and 0.739 (±0.239 mm respectively. The most errors were found in areas surrounding the lips and the eyes, while minimal errors were noted in the forehead, root of the nose and zygoma. CONCLUSIONS: CBCT and 3-D photographic data can be successfully fused with minimal errors. When compared to RMS, the signed average was found to under-represent the registration error. The virtual 3-D composite craniofacial models permit concurrent assessment of bone and soft tissues during diagnosis and treatment planning.

  11. Classification of teeth in cone-beam CT using deep convolutional neural network.

    Science.gov (United States)

    Miki, Yuma; Muramatsu, Chisako; Hayashi, Tatsuro; Zhou, Xiangrong; Hara, Takeshi; Katsumata, Akitoshi; Fujita, Hiroshi

    2017-01-01

    Dental records play an important role in forensic identification. To this end, postmortem dental findings and teeth conditions are recorded in a dental chart and compared with those of antemortem records. However, most dentists are inexperienced at recording the dental chart for corpses, and it is a physically and mentally laborious task, especially in large scale disasters. Our goal is to automate the dental filing process by using dental x-ray images. In this study, we investigated the application of a deep convolutional neural network (DCNN) for classifying tooth types on dental cone-beam computed tomography (CT) images. Regions of interest (ROIs) including single teeth were extracted from CT slices. Fifty two CT volumes were randomly divided into 42 training and 10 test cases, and the ROIs obtained from the training cases were used for training the DCNN. For examining the sampling effect, random sampling was performed 3 times, and training and testing were repeated. We used the AlexNet network architecture provided in the Caffe framework, which consists of 5 convolution layers, 3 pooling layers, and 2 full connection layers. For reducing the overtraining effect, we augmented the data by image rotation and intensity transformation. The test ROIs were classified into 7 tooth types by the trained network. The average classification accuracy using the augmented training data by image rotation and intensity transformation was 88.8%. Compared with the result without data augmentation, data augmentation resulted in an approximately 5% improvement in classification accuracy. This indicates that the further improvement can be expected by expanding the CT dataset. Unlike the conventional methods, the proposed method is advantageous in obtaining high classification accuracy without the need for precise tooth segmentation. The proposed tooth classification method can be useful in automatic filing of dental charts for forensic identification. Copyright © 2016 Elsevier Ltd

  12. Cone beam computed tomography images fusion in predicting lung ablation volumes: a feasibility study.

    Science.gov (United States)

    Ierardi, Anna Maria; Petrillo, Mario; Xhepa, Genti; Laganà, Domenico; Piacentino, Filippo; Floridi, Chiara; Duka, Ejona; Fugazzola, Carlo; Carrafiello, Gianpaolo

    2016-02-01

    Recently different software with the ability to plan ablation volumes have been developed in order to minimize the number of attempts of positioning electrodes and to improve a safe overall tumor coverage. To assess the feasibility of three-dimensional cone beam computed tomography (3D CBCT) fusion imaging with "virtual probe" positioning, to predict ablation volume in lung tumors treated percutaneously. Pre-procedural computed tomography contrast-enhanced scans (CECT) were merged with a CBCT volume obtained to plan the ablation. An offline tumor segmentation was performed to determine the number of antennae and their positioning within the tumor. The volume of ablation obtained, evaluated on CECT performed after 1 month, was compared with the pre-procedural predicted one. Feasibility was assessed on the basis of accuracy evaluation (visual evaluation [VE] and quantitative evaluation [QE]), technical success (TS), and technical effectiveness (TE). Seven of the patients with lung tumor treated by percutaneous thermal ablation were selected and treated on the basis of the 3D CBCT fusion imaging. In all cases the volume of ablation predicted was in accordance with that obtained. The difference in volume between predicted ablation volumes and obtained ones on CECT at 1 month was 1.8 cm(3) (SD ± 2, min. 0.4, max. 0.9) for MW and 0.9 cm(3) (SD ± 1.1, min. 0.1, max. 0.7) for RF. Use of pre-procedural 3D CBCT fusion imaging could be useful to define expected ablation volumes. However, more patients are needed to ensure stronger evidence. © The Foundation Acta Radiologica 2015.

  13. SU-E-T-161: Evaluation of Dose Calculation Based On Cone-Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Abe, T; Nakazawa, T; Saitou, Y; Nakata, A; Yano, M [Graduate School of Medicine, Sapporo Medical University, Sapporo, Hokkaido (Japan); Tateoka, K [Graduate School of Medicine, Sapporo Medical University, Sapporo, Hokkaido (Japan); Radiation Therapy Research Institute, Social Medical Corporation Teishinkai, Sapporo, Hokkaido (Japan); Fujimoto, K [Radiation Therapy Research Institute, Social Medical Corporation Teishinkai, Sapporo, Hokkaido (Japan); Sakata, K [Graduate School of Medicine, Sapporo Medical University, Sapporo, Hokkaido (Japan); Sapporo Medical University, Sapporo, Hokkaido (Japan)

    2014-06-01

    Purpose: The purpose of this study is to convert pixel values in cone-beam CT (CBCT) using histograms of pixel values in the simulation CT (sim-CT) and the CBCT images and to evaluate the accuracy of dose calculation based on the CBCT. Methods: The sim-CT and CBCT images immediately before the treatment of 10 prostate cancer patients were acquired. Because of insufficient calibration of the pixel values in the CBCT, it is difficult to be directly used for dose calculation. The pixel values in the CBCT images were converted using an in-house program. A 7 fields treatment plans (original plan) created on the sim-CT images were applied to the CBCT images and the dose distributions were re-calculated with same monitor units (MUs). These prescription doses were compared with those of original plans. Results: In the results of the pixel values conversion in the CBCT images,the mean differences of pixel values for the prostate,subcutaneous adipose, muscle and right-femur were −10.78±34.60, 11.78±41.06, 29.49±36.99 and 0.14±31.15 respectively. In the results of the calculated doses, the mean differences of prescription doses for 7 fields were 4.13±0.95%, 0.34±0.86%, −0.05±0.55%, 1.35±0.98%, 1.77±0.56%, 0.89±0.69% and 1.69±0.71% respectively and as a whole, the difference of prescription dose was 1.54±0.4%. Conclusion: The dose calculation on the CBCT images achieve an accuracy of <2% by using this pixel values conversion program. This may enable implementation of efficient adaptive radiotherapy.

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

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    Full Text Available 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.

  15. Positional relationship between mandibular third molar and mandibular canal in cone beam computed tomographs

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    Yu, Su Kyung; Lee, Ji Un; Kim, Kyoung A; Koh, Kwang Joon [Chonbuk National Univ. Hospital, Chonju (Korea, Republic of)

    2007-12-15

    To provide diagnostic information by evaluation of the positional relationship between the mandibular third molar and the mandibular canal. Eighty-nine mandibular third molars were classified as mesioangular, horizontal, vertical, distoangular groups. The distances between the mandibular third molar and the mandibular canal were measured in cone-beam computed tomographs. The height and width ratios of distances from the mandibular third molar and the mandibular canal to the mandibular inferior border and to the lingual cortical plate were calculated. The vertical and buccolingual distances between the mandibular third molar and the mandibular canal were 0.03 mm, 2.96 mm in the mesioangular, 0.37 mm, 3.38 ,, in the horizontal, -1.50 mm, 1.38 mm in the vertical, -1.10 mm, 4.20 mm in the distoangular group. There were significant differences in vertical (P<0.05), but not in buccolingual (P>0.05). The height and width ratios of distances on the mandibular third molar were 47.1%, 36.1% in the mesioangular, 47.4%, 34.4% in the horizontal, 37.0%, 46.7% in the vertical, 40.9%, 37.4% in the distoangular group. There were significant differences between the mesioangular and the vertical group, and the horizontal and the vertical group in height ratio (P>0.05). The mesioangular group showed the nearest distance between the mandibular third molar and the mandibular canal vertically. The root apex of the mandibular third molar was positioned more buccally in the vertical group than in the mesioangular group.

  16. Integration of digital dental casts in cone beam computed tomography scans-a clinical validation study.

    Science.gov (United States)

    Rangel, Frits A; Maal, Thomas J J; de Koning, Martien J J; Bronkhorst, Ewald M; Bergé, Stefaan J; Kuijpers-Jagtman, Anne Marie

    2017-09-20

    Images derived from cone beam computed tomography (CBCT) scans lack detailed information on the dentition and interocclusal relationships needed for proper surgical planning and production of surgical splints. To get a proper representation of the dentition, integration of a digital dental model into the CBCT scan is necessary. The aim of this study was to validate a simplified protocol to integrate digital dental models into CBCT scans using only one scan. Conventional protocol A used one combined upper and lower impression and two CBCT scans. The new protocol B included placement of ten markers on the gingiva, one CBCT scan, and two separate impressions of the upper and lower dentition. Twenty consecutive patients, scheduled for mandibular advancement surgery, were included. To validate protocol B, 3-dimensional reconstructions were made, which were compared by calculating the mean intersurface distances obtained with both protocols. The mean distance for all patients for the upper jaw is 0.39 mm and for the lower jaw is 0.30 mm. For ten out of 20 patients, all distances were less than 1 mm. For the other ten patients, all distances were less than 2 mm. Mean distances of 0.39 and 0.30 mm are clinically acceptable and comparable to other studies; therefore, this new protocol is clinically accurate. This new protocol seems to be clinically accurate. It is less time consuming, gives less radiation exposure for the patient, and has a lower risk for positional errors of the impressions compared to other integration protocols.

  17. Deformable registration of CT and cone-beam CT with local intensity matching

    Science.gov (United States)

    Park, Seyoun; Plishker, William; Quon, Harry; Wong, John; Shekhar, Raj; Lee, Junghoon

    2017-02-01

    Cone-beam CT (CBCT) is a widely used intra-operative imaging modality in image-guided radiotherapy and surgery. A short scan followed by a filtered-backprojection is typically used for CBCT reconstruction. While data on the mid-plane (plane of source-detector rotation) is complete, off-mid-planes undergo different information deficiency and the computed reconstructions are approximate. This causes different reconstruction artifacts at off-mid-planes depending on slice locations, and therefore impedes accurate registration between CT and CBCT. In this paper, we propose a method to accurately register CT and CBCT by iteratively matching local CT and CBCT intensities. We correct CBCT intensities by matching local intensity histograms slice by slice in conjunction with intensity-based deformable registration. The correction-registration steps are repeated in an alternating way until the result image converges. We integrate the intensity matching into three different deformable registration methods, B-spline, demons, and optical flow that are widely used for CT-CBCT registration. All three registration methods were implemented on a graphics processing unit for efficient parallel computation. We tested the proposed methods on twenty five head and neck cancer cases and compared the performance with state-of-the-art registration methods. Normalized cross correlation (NCC), structural similarity index (SSIM), and target registration error (TRE) were computed to evaluate the registration performance. Our method produced overall NCC of 0.96, SSIM of 0.94, and TRE of 2.26 → 2.27 mm, outperforming existing methods by 9%, 12%, and 27%, respectively. Experimental results also show that our method performs consistently and is more accurate than existing algorithms, and also computationally efficient.

  18. Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Kazunori, E-mail: kazokada@sfsu.edu [Department of Computer Science, San Francisco State University, San Francisco, California 94132 (United States); Rysavy, Steven [Biomedical and Health Informatics Program, University of Washington, Seattle, Washington 98195 (United States); Flores, Arturo [Computer Science and Engineering, University of California, San Diego, California 92093 (United States); Linguraru, Marius George [Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Medical Center, Washington, DC 20010 and Departments of Radiology and Pediatrics, George Washington University, Washington, DC 20037 (United States)

    2015-04-15

    Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.

  19. Influence of Intracanal Materials in Vertical Root Fracture Pathway Detection with Cone-beam Computed Tomography.

    Science.gov (United States)

    Dutra, Kamile Leonardi; Pachêco-Pereira, Camila; Bortoluzzi, Eduardo Antunes; Flores-Mir, Carlos; Lagravère, Manuel O; Corrêa, Márcio

    2017-07-01

    Investigating the vertical root fracture (VRF) pathway under different clinical scenarios may help to diagnose this condition properly. We aimed to determine the capability and intrareliability of VRF pathway detection through cone-beam computed tomographic (CBCT) imaging as well as analyze the influence of different intracanal and crown materials. VRFs were mechanically induced in 30 teeth, and 4 clinical situations were reproduced in vitro: no filling, gutta-percha, post, and metal crown. A Prexion (San Mateo, CA) 3-dimensional tomographic device was used to generate 104 CBCT scans. The VRF pathway was determined by using landmarks in the Avizo software (Version 8.1; FEI Visualization Sciences Group, Burlington, MA) by 1 observer repeated 3 times. Analysis of variance and post hoc tests were applied to compare groups. Intrareliability demonstrated an excellent agreement (intraclass correlation coefficient mean = 0.93). Descriptive analysis showed that the fracture line measurement was smaller in the post and metal crown groups than in the no-filling and gutta-percha groups. The 1-way analysis of variance test found statistically significant differences among the groups measurements. The Bonferroni correction showed statistically significant differences related to the no-filling and gutta-percha groups versus the post and metal crown groups. The VRF pathway can be accurately detected in a nonfilled tooth using limited field of view CBCT imaging. The presence of gutta-percha generated a low beam hardening artifact that did not hinder the VRF extent. The presence of an intracanal gold post made the fracture line appear smaller than it really was in the sagittal images; in the axial images, a VRF was only detected when the apical third was involved. The presence of a metal crown did not generate additional artifacts on the root surface compared to the intracanal gold post by itself. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc

  20. Usefulness of Cone-Beam Computed Tomography and Automatic Vessel Detection Software in Emergency Transarterial Embolization

    Energy Technology Data Exchange (ETDEWEB)

    Carrafiello, Gianpaolo, E-mail: gcarraf@gmail.com; Ierardi, Anna Maria, E-mail: amierardi@yahoo.it; Duka, Ejona, E-mail: ejonaduka@hotmail.com [Insubria University, Department of Radiology, Interventional Radiology (Italy); Radaelli, Alessandro, E-mail: alessandro.radaelli@philips.com [Philips Healthcare (Netherlands); Floridi, Chiara, E-mail: chiara.floridi@gmail.com [Insubria University, Department of Radiology, Interventional Radiology (Italy); Bacuzzi, Alessandro, E-mail: alessandro.bacuzzi@ospedale.varese.it [University of Insubria, Anaesthesia and Palliative Care (Italy); Bucourt, Maximilian de, E-mail: maximilian.de-bucourt@charite.de [Charité - University Medicine Berlin, Department of Radiology (Germany); Marchi, Giuseppe De, E-mail: giuseppedemarchi@email.it [Insubria University, Department of Radiology, Interventional Radiology (Italy)

    2016-04-15

    BackgroundThis study was designed to evaluate the utility of dual phase cone beam computed tomography (DP-CBCT) and automatic vessel detection (AVD) software to guide transarterial embolization (TAE) of angiographically challenging arterial bleedings in emergency settings.MethodsTwenty patients with an arterial bleeding at computed tomography angiography and an inconclusive identification of the bleeding vessel at the initial 2D angiographic series were included. Accuracy of DP-CBCT and AVD software were defined as the ability to detect the bleeding site and the culprit arterial bleeder, respectively. Technical success was defined as the correct positioning of the microcatheter using AVD software. Clinical success was defined as the successful embolization. Total volume of iodinated contrast medium and overall procedure time were registered.ResultsThe bleeding site was not detected by initial angiogram in 20 % of cases, while impossibility to identify the bleeding vessel was the reason for inclusion in the remaining cases. The bleeding site was detected by DP-CBCT in 19 of 20 (95 %) patients; in one case CBCT-CT fusion was required. AVD software identified the culprit arterial branch in 18 of 20 (90 %) cases. In two cases, vessel tracking required manual marking of the candidate arterial bleeder. Technical success was 95 %. Successful embolization was achieved in all patients. Mean contrast volume injected for each patient was 77.5 ml, and mean overall procedural time was 50 min.ConclusionsC-arm CBCT and AVD software during TAE of angiographically challenging arterial bleedings is feasible and may facilitate successful embolization. Staff training in CBCT imaging and software manipulation is necessary.

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

    Energy Technology Data Exchange (ETDEWEB)

    Barngkgei, Imad; Al Haffar, Iyad [Dept. of Oral Medicine, Faculty of Dentistry, Damascus University, Damascus (Syrian Arab Republic); Khattab, Razan [Dept. of Periodontology, Faculty of Dentistry, Damascus University, Damascus (Syrian Arab Republic)

    2014-12-15

    This study aimed to evaluate the use of dental cone-beam computed tomography (CBCT) in the diagnosis of osteoporosis among menopausal and postmenopausal women by using only a CBCT viewer program. Thirty-eight menopausal and postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) examination for hip and lumbar vertebrae were scanned using CBCT (field of view: 13 cmx15 cm; voxel size: 0.25 mm). Slices from the body of the mandible as well as the ramus were selected and some CBCT-derived variables, such as radiographic density (RD) as gray values, were calculated as gray values. Pearson's correlation, one-way analysis of variance (ANOVA), and accuracy (sensitivity and specificity) evaluation based on linear and logistic regression were performed to choose the variable that best correlated with the lumbar and femoral neck T-scores. RD of the whole bone area of the mandible was the variable that best correlated with and predicted both the femoral neck and the lumbar vertebrae T-scores; further, Pearson's correlation coefficients were 0.5/0.6 (p value=0.037/0.009). The sensitivity, specificity, and accuracy based on the logistic regression were 50%, 88.9%, and 78.4%, respectively, for the femoral neck, and 46.2%, 91.3%, and 75%, respectively, for the lumbar vertebrae. Lumbar vertebrae and femoral neck osteoporosis can be predicted with high accuracy from the RD value of the body of the mandible by using a CBCT viewer program.

  2. Three-rooted premolar analyzed by high-resolution and cone beam CT.

    Science.gov (United States)

    Marca, Caroline; Dummer, Paul M H; Bryant, Susan; Vier-Pelisser, Fabiana Vieira; Só, Marcus Vinicius Reis; Fontanella, Vania; Dutra, Vinicius D'avila; de Figueiredo, José Antonio Poli

    2013-07-01

    The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (μCT) and cone beam computed tomography (CBCT). Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using μCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using μCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. Images using μCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the μCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional μCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. Although variation was similar in the roots and canals under study, CBCT produced poorer image details than μCT. Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.

  3. SU-E-I-11: A New Cone-Beam CT System for Bedside Head Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sun, H; Zeng, W; Xu, P; Wang, Z; Xing, X; Sun, M [Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Jiangsu (China)

    2015-06-15

    Purpose: To design and develop a new mobile cone-beam CT (CBCT) system for head imaging with good soft-tissue visibility, to be used bedside in ICU and neurosurgery department to monitor treatment and operation outcome in brain patients. Methods: The imaging chain consists of a 30cmx25cm amorphous silicon flat panel detector and a pulsed, stationary anode monoblock x-ray source of 100kVp at a maximal tube current of 10mA. The detector and source are supported on motorized mechanisms to provide detector lateral shift and source angular tilt, enabling a centered digital radiographic imaging mode and half-fan CBCT, while maximizing the use of the x-ray field and keep the source to detector distance short. A focused linear anti-scatter grid is mounted on the detector, and commercial software with scatter and other corrective algorithms is used for data processing and image reconstruction. The gantry rotates around a horizontal axis, and is able to adjust its height for different patient table positions. Cables are routed through a custom protective sleeve over a large bore with an in-plane twister band, facilitating single 360-degree rotation without a slip-ring at a speed up to 5 seconds per rotation. A UPS provides about 10 minutes of operation off the battery when unplugged. The gantry is on locked casters, whose brake is control by two push handles on both sides for easy reposition. The entire system is designed to have a light weight and a compact size for excellent maneuverability. Results: System design is complete and main imaging components are tested. Initial results will be presented and discussed later in the presentation. Conclusion: A new mobile CBCT system for head imaging is being developed. With its compact size, a large bore, and quality design, it is expected to be a useful imaging tool for bedside uses. The work is supported by a grant from Chinese Academy of Sciences.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cazzato, Roberto Luigi, E-mail: r.cazzato@unicampus.it; Battistuzzi, Jean-Benoit, E-mail: j.battistuzzi@bordeaux.unicancer.fr; Catena, Vittorio, E-mail: vittoriocatena@gmail.com [Institut Bergonié, Department of Radiology (France); Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it; Zobel, Bruno Beomonte, E-mail: b.zobel@unicampus.it [Università Campus Bio-Medico di Roma, Department of Radiology and Diagnostic Imaging (Italy); Schena, Emiliano, E-mail: e.schena@unicampus.it [Università Campus Bio-Medico di Roma, Unit of Measurements and Biomedical Instrumentations, Biomedical Engineering Laboratory (Italy); Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr; Palussiere, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France)

    2015-10-15

    AimTo compare cone-beam CT (CBCT) versus computed tomography (CT) guidance in terms of time needed to target and place the radiofrequency ablation (RFA) electrode on lung tumours.Materials and MethodsPatients at our institution who received CBCT- or CT-guided RFA for primary or metastatic lung tumours were retrospectively included. Time required to target and place the RFA electrode within the lesion was registered and compared across the two groups. Lesions were stratified into three groups according to their size (<10, 10–20, >20 mm). Occurrences of electrode repositioning, repositioning time, RFA complications, and local recurrence after RFA were also reported.ResultsForty tumours (22 under CT, 18 under CBCT guidance) were treated in 27 patients (19 male, 8 female, median age 67.25 ± 9.13 years). Thirty RFA sessions (16 under CBCT and 14 under CT guidance) were performed. Multivariable linear regression analysis showed that CBCT was faster than CT to target and place the electrode within the tumour independently from its size (β = −9.45, t = −3.09, p = 0.004). Electrode repositioning was required in 10/22 (45.4 %) tumours under CT guidance and 5/18 (27.8 %) tumours under CBCT guidance. Pneumothoraces occurred in 6/14 (42.8 %) sessions under CT guidance and in 6/16 (37.5 %) sessions under CBCT guidance. Two recurrences were noted for tumours receiving CBCT-guided RFA (2/17, 11.7 %) and three after CT-guided RFA (3/19, 15.8 %).ConclusionCBCT with live 3D needle guidance is a useful technique for percutaneous lung ablation. Despite lesion size, CBCT allows faster lung RFA than CT.

  5. Maxillary dental anomalies in patients with cleft lip and palate: a cone beam computed tomography study.

    Science.gov (United States)

    Celikoglu, M; Buyuk, S K; Sekerci, A E; Cantekin, K; Candirli, C

    2015-01-01

    To compare the frequency of maxillary dental anomalies in patients affected by unilateral (UCLP) and bilateral (BCLP) cleft lip with palate and to determine whether statistical differences were present or not between cleft and normal sides in UCLP group by using cone beam computed tomography (CBCT). In addition, the frequency of those dental anomalies was compared with previous studies presenting the same population without cleft Study Design: Fifty non-syndromic patients affected by UCLP (28 patients) and BCLP (22 patients) were selected for analysis of dental anomalies by means of CBCT. The frequency of maxillary dental anomalies including tooth agenesis, microdontia of lateral incisor, ectopic eruption and impaction of canine and supernumerary tooth were examined. Pearson chi-square and Fisher's exact tests were performed for statistical comparisons. All patients affected by UCLP and BCLP were found to have at least one maxillary dental anomaly. The most frequently observed dental anomaly was tooth agenesis (92.5% and 86.4%, respectively) in UCLP and BCLP groups. Tooth agenesis and canine impaction were observed more commonly in the cleft side (75.0% and 35.7%, respectively) than in the normal side (57.1% and 14.3%, respectively) in UCLP group (p≯0.05). All dental anomalies were found to be higher in both cleft groups than in general populations not affected by cleft. Since patients affected by UCLP and BCLP had at least one dental anomaly and higher dental anomaly frequency as compared to patients without cleft, those patients should be examined carefully prior to orthodontic treatment.

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

    Science.gov (United States)

    Muinelo-Lorenzo, Juan; Fernández-Alonso, Ana; Smyth-Chamosa, Ernesto; Suárez-Quintanilla, Juan Antonio; Varela-Mallou, Jesús; Suárez-Cunqueiro, María Mercedes

    2017-01-01

    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. 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). 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). 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.

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

    Science.gov (United States)

    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 lin