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Sample records for 2d digital radiographic

  1. GPU accelerated generation of digitally reconstructed radiographs for 2-D/3-D image registration.

    PubMed

    Dorgham, Osama M; Laycock, Stephen D; Fisher, Mark H

    2012-09-01

    Recent advances in programming languages for graphics processing units (GPUs) provide developers with a convenient way of implementing applications which can be executed on the CPU and GPU interchangeably. GPUs are becoming relatively cheap, powerful, and widely available hardware components, which can be used to perform intensive calculations. The last decade of hardware performance developments shows that GPU-based computation is progressing significantly faster than CPU-based computation, particularly if one considers the execution of highly parallelisable algorithms. Future predictions illustrate that this trend is likely to continue. In this paper, we introduce a way of accelerating 2-D/3-D image registration by developing a hybrid system which executes on the CPU and utilizes the GPU for parallelizing the generation of digitally reconstructed radiographs (DRRs). Based on the advancements of the GPU over the CPU, it is timely to exploit the benefits of many-core GPU technology by developing algorithms for DRR generation. Although some previous work has investigated the rendering of DRRs using the GPU, this paper investigates approximations which reduce the computational overhead while still maintaining a quality consistent with that needed for 2-D/3-D registration with sufficient accuracy to be clinically acceptable in certain applications of radiation oncology. Furthermore, by comparing implementations of 2-D/3-D registration on the CPU and GPU, we investigate current performance and propose an optimal framework for PC implementations addressing the rigid registration problem. Using this framework, we are able to render DRR images from a 256×256×133 CT volume in ~24 ms using an NVidia GeForce 8800 GTX and in ~2 ms using NVidia GeForce GTX 580. In addition to applications requiring fast automatic patient setup, these levels of performance suggest image-guided radiation therapy at video frame rates is technically feasible using relatively low cost PC

  2. Calcification content quantification by dual-energy x-ray absorptiometry with a 2D digital radiographic detector

    NASA Astrophysics Data System (ADS)

    Dinten, Jean M.; Robert-Coutant, Christine; Darboux, Michel; Gonon, Georges; Bordy, Thomas

    2003-06-01

    In a previous paper (SPIE Medical Imaging 2001), a dual energy method for bone densitometry using a 2D digital radiographic detector has been presented. In this paper, calcium content quantification performance of the approach is precised. The main challenge is to achieve quantification using scatter-corrected dual energy acquisitions. Therefore a scatter estimation approach, based on an expression of scatter as a functional of the primary flux, has been developed. This expression is derived from the Klein and Nishina equation and includes tabulated scatter level values. The calcium quantification performances are validated on two configurations. A first one is issued from criteria developed by the French "Groupe de Recherche et d'Information sur les Osteoporoses." It is based on the use of a phantom made of five 3mm thick PVC sheets in the form of five steps, representing five different bone mineral density values, included in a lucite container filled with water. Additional lucite plates can be put over the phantom. This phantom has been used for evaluation of quantification robustness versus patient thickness and composition variations, and for accuracy evaluation. The second configuration, composed of small calcified objects (representative of lung nodules), is used for evaluating capacities to differentiate calcified from non calcified nodules and to test calcium content quantification performance.

  3. Comparison Of Digital Radiographic Units

    NASA Astrophysics Data System (ADS)

    Wang, Yen

    1986-06-01

    A total PACS will be inevitable for radiology practice within several years. To achieve a total PACS for radiology, a satisfactory digital radiographic unit is required, because approximately 65% of digital data for PACS comes from digital radiographs. There are several possibilities for producing digital radiographs, and 3 - 4 companies have been marketing digital radiographic devices. Some data regarding the digital radiographic units on the market are compared. It will aid in assessing the current status and availability of this aspect of development, as well as providing a summary of further development of digital radiographic technology.

  4. DIGITAL SPALL RADIOGRAPH ANALYSIS SYSTEM

    SciTech Connect

    CURTIS L. HARRIS - LATA

    1990-01-01

    This report describes progress on work to develop a cost effective, rapid response system for measuring Technology Assessment National Laboratory. momentum and kinetic energy of span for the Advanced Center (ATAC) Armor/Anti-Armor (As) program at Los Alamos The system will exploit data contained in two sets of simultaneous co-planar flash radiographs taken along the center line of anticipated span motion. Data contained in each set (which is proportional to the mass and z-number of the span material intersected by the exposing x-ray at each point) is digitized and used to construct a three dimensional model (called the reconstructed span image) that approximates the original span cloud. From the model the mass of span fragments is computed. The two sets of radiographs, separated in time, represent the span configuration at two instants of time. Span fragments from the first instant are matched with those from the second instant to determine velocity. Evaluation of the fidelity of candidate reconstruction algorithms is the highest priority task in. this development program for the obvious reason that the efficacy of the projected span analysis system depends upon the fidelity of the reconstruction techniques.

  5. Digital processing of radiographic images

    NASA Technical Reports Server (NTRS)

    Bond, A. D.; Ramapriyan, H. K.

    1973-01-01

    Some techniques are presented and the software documentation for the digital enhancement of radiographs. Both image handling and image processing operations are considered. The image handling operations dealt with are: (1) conversion of format of data from packed to unpacked and vice versa; (2) automatic extraction of image data arrays; (3) transposition and 90 deg rotations of large data arrays; (4) translation of data arrays for registration; and (5) reduction of the dimensions of data arrays by integral factors. Both the frequency and the spatial domain approaches are presented for the design and implementation of the image processing operation. It is shown that spatial domain recursive implementation of filters is much faster than nonrecursive implementations using fast fourier transforms (FFT) for the cases of interest in this work. The recursive implementation of a class of matched filters for enhancing image signal to noise ratio is described. Test patterns are used to illustrate the filtering operations. The application of the techniques to radiographic images of metallic structures is demonstrated through several examples.

  6. MRI visualisation by digitally reconstructed radiographs

    NASA Astrophysics Data System (ADS)

    Serrurier, Antoine; Bönsch, Andrea; Lau, Robert; Deserno, Thomas M.

    2015-03-01

    Visualising volumetric medical images such as computed tomography and magnetic resonance imaging (MRI) on picture archiving and communication systems (PACS) clients is often achieved by image browsing in sagittal, coronal or axial views or three-dimensional (3D) rendering. This latter technique requires fine thresholding for MRI. On the other hand, computing virtual radiograph images, also referred to as digitally reconstructed radiographs (DRR), provides in a single two-dimensional (2D) image a complete overview of the 3D data. It appears therefore as a powerful alternative for MRI visualisation and preview in PACS. This study describes a method to compute DRR from T1-weighted MRI. After segmentation of the background, a histogram distribution analysis is performed and each foreground MRI voxel is labeled as one of three tissues: cortical bone, also known as principal absorber of the X-rays, muscle and fat. An intensity level is attributed to each voxel according to the Hounsfield scale, linearly related to the X-ray attenuation coefficient. Each DRR pixel is computed as the accumulation of the new intensities of the MRI dataset along the corresponding X-ray. The method has been tested on 16 T1-weighted MRI sets. Anterior-posterior and lateral DRR have been computed with reasonable qualities and avoiding any manual tissue segmentations. This proof-of-concept holds for research application for use in clinical PACS.

  7. Digital radiographic systems detect boiler tube cracks

    SciTech Connect

    Walker, S.

    2008-06-15

    Boiler water wall leaks have been a major cause of steam plant forced outages. But conventional nondestructive evaluation techniques have a poor track record of detecting corrosion fatigue cracking on the inside surface of the cold side of waterwall tubing. EPRI is performing field trials of a prototype direct-digital radiographic system that promises to be a game changer. 8 figs.

  8. 3D-2D registration in mobile radiographs: algorithm development and preliminary clinical evaluation

    NASA Astrophysics Data System (ADS)

    Otake, Yoshito; Wang, Adam S.; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Aygun, Nafi; Lo, Sheng-fu L.; Wolinsky, Jean-Paul; Gokaslan, Ziya L.; Siewerdsen, Jeffrey H.

    2015-03-01

    An image-based 3D-2D registration method is presented using radiographs acquired in the uncalibrated, unconstrained geometry of mobile radiography. The approach extends a previous method for six degree-of-freedom (DOF) registration in C-arm fluoroscopy (namely ‘LevelCheck’) to solve the 9-DOF estimate of geometry in which the position of the source and detector are unconstrained. The method was implemented using a gradient correlation similarity metric and stochastic derivative-free optimization on a GPU. Development and evaluation were conducted in three steps. First, simulation studies were performed that involved a CT scan of an anthropomorphic body phantom and 1000 randomly generated digitally reconstructed radiographs in posterior-anterior and lateral views. A median projection distance error (PDE) of 0.007 mm was achieved with 9-DOF registration compared to 0.767 mm for 6-DOF. Second, cadaver studies were conducted using mobile radiographs acquired in three anatomical regions (thorax, abdomen and pelvis) and three levels of source-detector distance (~800, ~1000 and ~1200 mm). The 9-DOF method achieved a median PDE of 0.49 mm (compared to 2.53 mm for the 6-DOF method) and demonstrated robustness in the unconstrained imaging geometry. Finally, a retrospective clinical study was conducted with intraoperative radiographs of the spine exhibiting real anatomical deformation and image content mismatch (e.g. interventional devices in the radiograph that were not in the CT), demonstrating a PDE = 1.1 mm for the 9-DOF approach. Average computation time was 48.5 s, involving 687 701 function evaluations on average, compared to 18.2 s for the 6-DOF method. Despite the greater computational load, the 9-DOF method may offer a valuable tool for target localization (e.g. decision support in level counting) as well as safety and quality assurance checks at the conclusion of a procedure (e.g. overlay of planning data on the radiograph for verification of

  9. 3D–2D registration in mobile radiographs: algorithm development and preliminary clinical evaluation.

    PubMed

    Otake, Yoshito; Wang, Adam S; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Aygun, Nafi; Lo, Sheng-fu L; Wolinsky, Jean-Paul; Gokaslan, Ziya L; Siewerdsen, Jeffrey H

    2015-03-07

    An image-based 3D-2D registration method is presented using radiographs acquired in the uncalibrated, unconstrained geometry of mobile radiography. The approach extends a previous method for six degree-of-freedom (DOF) registration in C-arm fluoroscopy (namely 'LevelCheck') to solve the 9-DOF estimate of geometry in which the position of the source and detector are unconstrained. The method was implemented using a gradient correlation similarity metric and stochastic derivative-free optimization on a GPU. Development and evaluation were conducted in three steps. First, simulation studies were performed that involved a CT scan of an anthropomorphic body phantom and 1000 randomly generated digitally reconstructed radiographs in posterior-anterior and lateral views. A median projection distance error (PDE) of 0.007 mm was achieved with 9-DOF registration compared to 0.767 mm for 6-DOF. Second, cadaver studies were conducted using mobile radiographs acquired in three anatomical regions (thorax, abdomen and pelvis) and three levels of source-detector distance (~800, ~1000 and ~1200 mm). The 9-DOF method achieved a median PDE of 0.49 mm (compared to 2.53 mm for the 6-DOF method) and demonstrated robustness in the unconstrained imaging geometry. Finally, a retrospective clinical study was conducted with intraoperative radiographs of the spine exhibiting real anatomical deformation and image content mismatch (e.g. interventional devices in the radiograph that were not in the CT), demonstrating a PDE = 1.1 mm for the 9-DOF approach. Average computation time was 48.5 s, involving 687 701 function evaluations on average, compared to 18.2 s for the 6-DOF method. Despite the greater computational load, the 9-DOF method may offer a valuable tool for target localization (e.g. decision support in level counting) as well as safety and quality assurance checks at the conclusion of a procedure (e.g. overlay of planning data on the radiograph for verification of the surgical product

  10. 3D–2D registration in mobile radiographs: algorithm development and preliminary clinical evaluation

    PubMed Central

    Otake, Yoshito; Wang, Adam S; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Aygun, Nafi; Lo, Sheng-fu L; Wolinsky, Jean-Paul; Gokaslan, Ziya L; Siewerdsen, Jeffrey H

    2015-01-01

    An image-based 3D–2D registration method is presented using radiographs acquired in the uncalibrated, unconstrained geometry of mobile radiography. The approach extends a previous method for six degree-of-freedom (DOF) registration in C-arm fluoroscopy (namely ‘LevelCheck’) to solve the 9-DOF estimate of geometry in which the position of the source and detector are unconstrained. The method was implemented using a gradient correlation similarity metric and stochastic derivative-free optimization on a GPU. Development and evaluation were conducted in three steps. First, simulation studies were performed that involved a CT scan of an anthropomorphic body phantom and 1000 randomly generated digitally reconstructed radiographs in posterior–anterior and lateral views. A median projection distance error (PDE) of 0.007 mm was achieved with 9-DOF registration compared to 0.767 mm for 6-DOF. Second, cadaver studies were conducted using mobile radiographs acquired in three anatomical regions (thorax, abdomen and pelvis) and three levels of source-detector distance (~800, ~1000 and ~1200 mm). The 9-DOF method achieved a median PDE of 0.49 mm (compared to 2.53 mm for the 6-DOF method) and demonstrated robustness in the unconstrained imaging geometry. Finally, a retrospective clinical study was conducted with intraoperative radiographs of the spine exhibiting real anatomical deformation and image content mismatch (e.g. interventional devices in the radiograph that were not in the CT), demonstrating a PDE = 1.1 mm for the 9-DOF approach. Average computation time was 48.5 s, involving 687 701 function evaluations on average, compared to 18.2 s for the 6-DOF method. Despite the greater computational load, the 9-DOF method may offer a valuable tool for target localization (e.g. decision support in level counting) as well as safety and quality assurance checks at the conclusion of a procedure (e.g. overlay of planning data on the radiograph for verification of the surgical

  11. A procedure for the evaluation of 2D radiographic texture analysis to assess 3D bone micro-architecture

    NASA Astrophysics Data System (ADS)

    Apostol, Lian; Peyrin, Francoise; Yot, Sophie; Basset, Olivier; Odet, Christophe; Tabary, Joachim; Dinten, Jean-Marc; Boller, Elodie; Boudousq, Vincent; Kotzki, Pierre-Olivier

    2004-05-01

    Although the diagnosis of osteoporosis is mainly based on Dual X-ray Absorptiometry, it has been shown that trabecular bone micro-architecture is also an important factor in regards of fracture risk, which can be efficiently assessed in vitro using three-dimensional x-ray microtomography (μCT). In vivo, techniques based on high-resolution s-ray radiography associated to texture analysis have been proposed to investigate bone micro-architecture, but their relevance for giving pertinent 3D information is unclear. The purpose of this work was to develop a method for evaluating the relationships betweeen 3D micro-architecture and 2D texture parameters, and optimizing the conditions for radiographic imaging. Bone sample images taken from cortical to cortical were acquired using 3D-synchrotron x-ray μCT at the ESRF. The 3D digital imagees were further used for two purposes: 1) quantification of three-dimensional bone micro-architecture, 2) simulation of realistic x-ray radiographs under different acquisition conditions. Texture analysis was then applied to these 2D radiographs using a large variety of methods (co-occurence, spectrum, fractal...). First results of the statistical analysis between 2D and 3D parameters allowed identfying the most relevant 2D texture parameters.

  12. Segmentation of ribs in digital chest radiographs

    NASA Astrophysics Data System (ADS)

    Cong, Lin; Guo, Wei; Li, Qiang

    2016-03-01

    Ribs and clavicles in posterior-anterior (PA) digital chest radiographs often overlap with lung abnormalities such as nodules, and cause missing of these abnormalities, it is therefore necessary to remove or reduce the ribs in chest radiographs. The purpose of this study was to develop a fully automated algorithm to segment ribs within lung area in digital radiography (DR) for removal of the ribs. The rib segmentation algorithm consists of three steps. Firstly, a radiograph was pre-processed for contrast adjustment and noise removal; second, generalized Hough transform was employed to localize the lower boundary of the ribs. In the third step, a novel bilateral dynamic programming algorithm was used to accurately segment the upper and lower boundaries of ribs simultaneously. The width of the ribs and the smoothness of the rib boundaries were incorporated in the cost function of the bilateral dynamic programming for obtaining consistent results for the upper and lower boundaries. Our database consisted of 93 DR images, including, respectively, 23 and 70 images acquired with a DR system from Shanghai United-Imaging Healthcare Co. and from GE Healthcare Co. The rib localization algorithm achieved a sensitivity of 98.2% with 0.1 false positives per image. The accuracy of the detected ribs was further evaluated subjectively in 3 levels: "1", good; "2", acceptable; "3", poor. The percentages of good, acceptable, and poor segmentation results were 91.1%, 7.2%, and 1.7%, respectively. Our algorithm can obtain good segmentation results for ribs in chest radiography and would be useful for rib reduction in our future study.

  13. 3-D Reconstruction From 2-D Radiographic Images and Its Application to Clinical Veterinary Medicine

    NASA Astrophysics Data System (ADS)

    Hamamoto, Kazuhiko; Sato, Motoyoshi

    3D imaging technique is very important and indispensable in diagnosis. The main stream of the technique is one in which 3D image is reconstructed from a set of slice images, such as X-ray CT and MRI. However, these systems require large space and high costs. On the other hand, a low cost and small size 3D imaging system is needed in clinical veterinary medicine, for example, in the case of diagnosis in X-ray car or pasture area. We propose a novel 3D imaging technique using 2-D X-ray radiographic images. This system can be realized by cheaper system than X-ray CT and enables to get 3D image in X-ray car or portable X-ray equipment. In this paper, a 3D visualization technique from 2-D radiographic images is proposed and several reconstructions are shown. These reconstructions are evaluated by veterinarians.

  14. Automated 2D-3D registration of a radiograph and a cone beam CT using line-segment enhancement

    SciTech Connect

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

    2006-05-15

    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.

  15. A 2D 3D registration with low dose radiographic system for in vivo kinematic studies.

    PubMed

    Jerbi, T; Burdin, V; Stindel, E; Roux, C

    2011-01-01

    The knowledge of the poses and the positions of the knee bones and prostheses is of a great interest in the orthopedic and biomechanical applications. In this context, we use an ultra low dose bi-planar radiographic system called EOS to acquire two radiographs of the studied bones in each position. In this paper, we develop a new method for 2D 3D registration based on the frequency domain to determine the poses and the positions during quasi static motion analysis for healthy and prosthetic knees. Data of two healthy knees and four knees with unicompartimental prosthesis performing three different poses (full extension, 30° and 60° of flexion) were used in this work. The results we obtained are in concordance with the clinical accuracy and with the accuracy reported in other previous studies.

  16. High frame-rate digital radiographic videography

    SciTech Connect

    King, N.S.P.; Cverna, F.H.; Albright, K.L.; Jaramillo, S.A.; Yates, G.J.; McDonald, T.E.; Flynn, M.J.; Tashman, S.

    1994-09-01

    High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100-microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

  17. Digital image processing of cephalometric radiographs: a preliminary report.

    PubMed

    Jackson, P H; Dickson, G C; Birnie, D J

    1985-07-01

    The principles of image capture, image storage and image processing in digital radiology are described. The enhancement of radiographic images using digital image processing techniques and its application to cephalometry is discussed. The results of a pilot study which compared some common cephalometric measurements made from manual point identification with those made by direct digitization of digital radiographic images from video monitors are presented. Although in an early stage of development, the results from the image processing system were comparable with those obtained by traditional methods.

  18. Fraudulent use of digital radiography: methods to detect and protect digital radiographs.

    PubMed

    Calberson, Filip L G; Hommez, Geert M; De Moor, Roeland J

    2008-05-01

    Digital radiography has become an indispensable diagnostic tool in dentistry today. To improve vision and diagnosis, dental x-ray software allows image enhancement (eg, adjusting color, density, sharpness, brightness, or contrast). Exporting digital radiographs to a file format compatible with commercial graphic software increases chances that information can be altered, added, or removed in an unethical manner. Dental radiographs are easily duplicated, stored, or distributed in digital format. It is difficult to guarantee the authenticity of digital images, which is especially important in insurance or juridic cases. Image-enhancement features applied to digital radiographs allow mishandling or potential abuse. This has been illustrated by several recently published studies. A standard authentication procedure for digital radiographs is needed. A number of manipulated radiographic images are presented to show concerns about security, reliability, and the potential for fraud. Antitampering techniques and methods of detecting manipulations in digital medical images are discussed.

  19. Determinants Of Acceptability Of Radiographic Images For Archival Digital Storage

    NASA Astrophysics Data System (ADS)

    Markivee, C. R.; Nalesnik, W. J.; Chiang, M. C.; Tio, J. R.; Hall, E. L.

    1983-05-01

    The parameter, quality of radiographic film exposure, was evaluated by computer and 15 human observers for the purpose of determining the feasibility of automatic computer eval-uation of radiographs prior to archival storage. Histograms of digitized knee radiographs were parameterized according to the Pearson technique and the computer was used to grade exposure quality relative to a set of training radiographs evaluated by the readers. There was a significant variation in the assessment of film exposure quality among the different observers. The computer scored 73% for the AP films and 53% for the laterals relative to the general consensus. The discrepancies were explained in terms of differences in anatomy and radiographic technique. The significance of this work is that it demonstrates that a computer can grade films according to a predetermined standard set by the radiologist.

  20. Positioning evaluation of corrective osteotomy for the malunited radius: 3-D CT versus 2-D radiographs.

    PubMed

    Vroemen, Joy C; Dobbe, Johannes G G; Strackee, Simon D; Streekstra, Geert J

    2013-02-01

    The authors retrospectively investigated the postoperative position of the distal radius after a corrective osteotomy using 2-dimensional (2-D) and 3-dimensional (3-D) imaging techniques to determine whether malposition correlates with clinical outcome. Twenty-five patients who underwent a corrective osteotomy were available for follow-up. The residual positioning errors of the distal end were determined retrospectively using standard 2-D radiographs and 3-D computed tomography evaluations based on a scan of both forearms, with the contralateral healthy radius serving as reference. For 3-D analysis, use of an anatomical coordinate system for each reference bone allowed the authors to express the residual malalignment parameters in displacements (Δx, Δy, Δz) and rotations (Δφx, Δφy, Δφz) for aligning the affected bone in a standardized way with the corresponding reference bone. The authors investigated possible correlations between malalignment parameters and clinical outcome using patients' questionnaires. Two-dimensional radiographic evaluation showed a radial inclination of 24.9°±6.8°, a palmar tilt of 4.5°±8.6°, and an ulnar variance of 0.8±1.7 mm. With 3-D analysis, residual displacements were 2.6±3 (Δx), 2.4±3 (Δy), and -2.2±4 (Δz) mm. Residual rotations were -6.2°±10° (Δφx), 0.3°±7° (Δφy), and -5.1°±10° (Δφz). The large standard deviation is indicative of persistent malalignment in individual cases. Statistically significant correlations were found between 3-D rotational deficits and clinical outcome but not between 2-D evaluation parameters. Considerable residual malalignments and statistically significant correlations between malalignment parameters and clinical outcome confirm the need for better positioning techniques.

  1. Digital processing of radiographic images from PACS to publishing.

    PubMed

    Christian, M E; Davidson, H C; Wiggins, R H; Berges, G; Cannon, G; Jackson, G; Chapman, B; Harnsberger, H R

    2001-03-01

    Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.

  2. Radiographic Trabecular 2D and 3D Parameters of Proximal Femoral Bone Cores Correlate with Each Other and with Yield Stress

    PubMed Central

    Steines, Daniel; Liew, Siau-Way; Arnaud, Claude; Voracek, Rene Vargas; Nazarian, Ara; Müller, Ralph; Snyder, Brian; Hess, Patrick; Lang, Philipp

    2010-01-01

    Introduction We compared morphometric measurements of trabecular patterns in two-dimensional (2D) projection radiographic images of cores from cadaver proximal femoral bones with conceptually equivalent measurements from three-dimensional (3D) μCT images. Methods Seven cadaver proximal femora provided 47 excised cores from seven regions. Digitized radiographs of those cores were processed with software that extracts trabecular patterns. Measurements of their distribution, geometry, and connectivity were compared with 3D parameters of similar definition derived from μCT of those cores. The relationship between 2D and 3D measurements and yield stress was also examined. Results 2D measurements strongly correlated with conceptually equivalent measurements obtained using 3D μCT. In all cases, the correlation coefficients were high, ranging from r=0.84 (p<0.001) to r=0.93 (p<0.001). The correlation coefficients between 2D and 3D measurements and yield stress of the cores were also high (r=0.60 and 0.82, p<0.001 respectively). Conclusions These findings provide correlative and biomechanical evidence supporting the qualitative similarity of 2D microstructural parameters extracted from plain proximal femoral core X-ray images to conceptually equivalent 3D microstuctural measurements of those same cores. PMID:19319618

  3. Distortion of digital panoramic radiographs used for implant site assessment

    PubMed Central

    Kayal, Rayyan Abdulhamid

    2016-01-01

    Aims: This study is conducted to determine the amount of distortion of digital panoramic radiographs. Materials and Methods: Panoramic radiographs of all patients who received dental implants in the years 2012 and 2013 were selected from the records at the faculty of dentistry, King Abdulaziz University. Radiographs were analyzed using the R4 Kodak Software for linear measurements of implants length and width. The measurements were compared to the actual size of the implant, and the amount of distortion was calculated. Results: A total of 169 implants were analyzed. Horizontally, there was a statistically significant increase of 0.4 mm in width in the radiographic measurement compared to the actual size in the incisor region. Vertically, the sample overall exhibited a decrease by 0.4 mm compared to the actual size. Incisors had the highest difference with a decrease of 1.7 mm in the radiographic measurements compared to actual size. The highest distortion was found in the incisor region for both diameter and length (1.1 and 0.86), respectively. Conclusion: Digital panoramic radiographs show minimal to no distortion. The highest distortion is found in the anterior area. PMID:27843885

  4. Digit ratio (2D:4D), salivary testosterone, and handedness.

    PubMed

    Beaton, Alan A; Rudling, Nick; Kissling, Christian; Taurines, Regine; Thome, Johannes

    2011-03-01

    The length of the index finger relative to that of the ring finger, the 2D:4D ratio, has been taken to be a marker of the amount of testosterone (T) that was present in the foetal environment (Manning, Scutt, Wilson, & Lewis-Jones, 1998). It has also been suggested (Geschwind & Galaburda, 1987) that elevated levels of foetal T are associated with left-handedness and that adult levels of circulating T might relate to foetal levels (Jamison, Meier, & Campbell, 1993). We used multiple regression analyses to investigate whether there is any relationship between either left or right hand 2D:4D ratio and handedness. We also examined whether adult levels of salivary T (or cortisol, used as a control hormone) predict digit ratio and/or handedness. Although the 2D:4D ratio of neither the left nor the right hand was related to handedness, the difference between the digit ratios of the right and left hands, D(R-L), was a significant predictor of handedness and of the performance difference between the hands on a peg-moving task, supporting previous findings (Manning & Peters, 2009; Manning et al., 1998; Manning, Trivers, Thornhill, & Singh, 2000; Stoyanov, Marinov, & Pashalieva, 2009). Adult circulating T levels did not predict the digit ratio of the left or right hand; nor was there a significant relationship between concentrations of salivary T (or cortisol) and either hand preference or asymmetry in manual skill. We suggest that the association between D(R-L) and hand preference arises because D(R-L) is a correlate of sensitivity to T in the developing foetus.

  5. ROC Detectability Evaluation Of A Filmless Digital Radiographic System

    NASA Astrophysics Data System (ADS)

    Shaber, Gary S.; Shlansky-Goldberg, Richard; D'Adamo, Arthur J.

    1988-06-01

    A new digital radiographic system (Matrix Laser Rad) employing a filmless photostimulable reusable phosphor (PSP) was evaluated for spatial resolution and high and low contrast object detectability. Receiver operator characteristic curve (ROC) comparisons were made to film images using equal or lower exposure factors. The low and high contrast test objects for the ROC evaluation were respectively a 5/32 inch diameter hemispheric depression filled with mineral oil and 250-500 micrometer diameter silicon carbide granules, both in a 2 inch thick plexiglass block. These object sizes were shown to be at thresh-old of detectability for either the film or PSP system at the exposure factors used. The ROC curves were generated from data obtained by radiologists viewing multiple film radiographs and CRT displays of both the digitized film radiographs and PSP images with the test objects in random locations. There were 90 images generated for each system, 45 with test objects and 45 without. Each observer had 15 seconds at a fixed distance to view each image presented at random at standard view box intensities (140 foot-lamberts) on either a light view box or CRT. The unenhanced filmless PSP radiographs had a reduced detectability threshold for the test objects, however with the use of windowing, level manipulations and appropriate filtering, detectability could be improved for the low contrast objects with the digital system surpassing unenhanced film radiographs. In addition, a dose reduction could be achieved with the PSP filmless system without loss of significant detectability. Enhanced film radiographs demonstrated the highest detectability characteristics. To achieve similar detectability for high contrast objects with the PSP system, a significant increase in object size was necessary.

  6. 2D-3D registration for brain radiation therapy using a 3D CBCT and a single limited field-of-view 2D kV radiograph

    NASA Astrophysics Data System (ADS)

    Munbodh, R.; Moseley, D. J.

    2014-03-01

    We report results of an intensity-based 2D-3D rigid registration framework for patient positioning and monitoring during brain radiotherapy. We evaluated two intensity-based similarity measures, the Pearson Correlation Coefficient (ICC) and Maximum Likelihood with Gaussian noise (MLG) derived from the statistics of transmission images. A useful image frequency band was identified from the bone-to-no-bone ratio. Validation was performed on gold-standard data consisting of 3D kV CBCT scans and 2D kV radiographs of an anthropomorphic head phantom acquired at 23 different poses with parameter variations along six degrees of freedom. At each pose, a single limited field of view kV radiograph was registered to the reference CBCT. The ground truth was determined from markers affixed to the phantom and visible in the CBCT images. The mean (and standard deviation) of the absolute errors in recovering each of the six transformation parameters along the x, y and z axes for ICC were varphix: 0.08(0.04)°, varphiy: 0.10(0.09)°, varphiz: 0.03(0.03)°, tx: 0.13(0.11) mm, ty: 0.08(0.06) mm and tz: 0.44(0.23) mm. For MLG, the corresponding results were varphix: 0.10(0.04)°, varphiy: 0.10(0.09)°, varphiz: 0.05(0.07)°, tx: 0.11(0.13) mm, ty: 0.05(0.05) mm and tz: 0.44(0.31) mm. It is feasible to accurately estimate all six transformation parameters from a 3D CBCT of the head and a single 2D kV radiograph within an intensity-based registration framework that incorporates the physics of transmission images.

  7. Age estimation based on Kvaal's technique using digital panoramic radiographs

    PubMed Central

    Mittal, Samta; Nagendrareddy, Suma Gundareddy; Sharma, Manisha Lakhanpal; Agnihotri, Poornapragna; Chaudhary, Sunil; Dhillon, Manu

    2016-01-01

    Introduction: Age estimation is important for administrative and ethical reasons and also because of legal consequences. Dental pulp undergoes regression in size with increasing age due to secondary dentin deposition and can be used as a parameter of age estimation even beyond 25 years of age. Kvaal et al. developed a method for chronological age estimation based on the pulp size using periapical dental radiographs. There is a need for testing this method of age estimation in the Indian population using simple tools like digital imaging on living individuals not requiring extraction of teeth. Aims and Objectives: Estimation of the chronological age of subjects by Kvaal's method using digital panoramic radiographs and also testing the validity of regression equations as given by Kvaal et al. Materials and Methods: The study sample included a total of 152 subjects in the age group of 14-60 years. Measurements were performed on the standardized digital panoramic radiographs based on Kvaal's method. Different regression formulae were derived and the age was assessed. The assessed age was then correlated to the actual age of the patient using Student's t-test. Results: No significant difference between the mean of the chronological age and the estimated age was observed. However, the values of the mean age estimated by using regression equations as given previously in the study of Kvaal et al. significantly underestimated the chronological age in the present study sample. Conclusion: The results of the study give an inference for the feasibility of this technique by calculation of regression equations on digital panoramic radiographs. However, it negates the applicability of same regression equations as given by Kvaal et al. on the study population. PMID:27555738

  8. 2-D-3-D frequency registration using a low-dose radiographic system for knee motion estimation.

    PubMed

    Jerbi, Taha; Burdin, Valerie; Leboucher, Julien; Stindel, Eric; Roux, Christian

    2013-03-01

    In this paper, a new method is presented to study the feasibility of the pose and the position estimation of bone structures using a low-dose radiographic system, the entrepreneurial operating system (designed by EOS-Imaging Company). This method is based on a 2-D-3-D registration of EOS bi-planar X-ray images with an EOS 3-D reconstruction. This technique is relevant to such an application thanks to the EOS ability to simultaneously make acquisitions of frontal and sagittal radiographs, and also to produce a 3-D surface reconstruction with its attached software. In this paper, the pose and position of a bone in radiographs is estimated through the link between 3-D and 2-D data. This relationship is established in the frequency domain using the Fourier central slice theorem. To estimate the pose and position of the bone, we define a distance between the 3-D data and the radiographs, and use an iterative optimization approach to converge toward the best estimation. In this paper, we give the mathematical details of the method. We also show the experimental protocol and the results, which validate our approach.

  9. Fast and accurate automated measurements in digitized stereophotogrammetric radiographs.

    PubMed

    Vrooman, H A; Valstar, E R; Brand, G J; Admiraal, D R; Rozing, P M; Reiber, J H

    1998-05-01

    Until recently, Roentgen Stereophotogrammetric Analysis (RSA) required the manual definition of all markers using a high-resolution measurement table. To automate this tedious and time-consuming process and to eliminate observer variabilities, an analytical software package has been developed and validated for the detection, identification, and matching of markers in RSA radiographs. The digital analysis procedure consisted of the following steps: (1) the detection of markers using a variant of the Hough circle-finder technique; (2) the identification and labeling of the detected markers; (3) the reconstruction of the three-dimensional position of the bone markers and the prosthetic markers; and (4) the computation of micromotion. To assess the influence of film digitization, the measurements obtained from nine phantom radiographs using two different film scanners were compared with the results obtained by manual processing. All markers in the phantom radiographs were automatically detected and correctly labeled. The best results were obtained with a Vidar VXR-12 CCD scanner, for which the measurement errors were comparable to the errors associated with the manual approach. To assess the in vivo reproducibility, 30 patient radiographs were analyzed twice with the manual as well as with the automated procedure. Approximately, 85% of all calibration markers and bone markers were automatically detected and correctly matched. The calibration errors and the rigid-body errors show that the accuracy of the automated procedure is comparable to the accuracy of the manual procedure. The rigid-body errors had comparable mean values for both techniques: 0.05 mm for the tibia and 0.06 mm for the prosthesis. The reproducibility of the automated procedure showed to be slightly better than that of the manual procedure. The maximum errors in the computed translation and rotation of the tibial component were 0.11 mm and 0.24, compared to 0.13 mm and 0.27 for the manual RSA procedure

  10. 42 CFR 37.51 - Interpreting and classifying chest radiographs-digital radiography systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-digital radiography systems. 37.51 Section 37.51 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH... of Chest Radiographs § 37.51 Interpreting and classifying chest radiographs—digital radiography systems. (a) For each chest radiograph obtained at an approved facility using a digital radiography...

  11. Relevance of 2D radiographic texture analysis for the assessment of 3D bone micro-architecture

    SciTech Connect

    Apostol, Lian; Boudousq, Vincent; Basset, Oliver; Odet, Christophe; Yot, Sophie; Tabary, Joachim; Dinten, Jean-Marc; Boller, Elodie; Kotzki, Pierre-Olivier; Peyrin, Francoise

    2006-09-15

    Although the diagnosis of osteoporosis is mainly based on dual x-ray absorptiometry, it has been shown that trabecular bone micro-architecture is also an important factor in regard to fracture risk. In vivo, techniques based on high-resolution x-ray radiography associated to texture analysis have been proposed to investigate bone micro-architecture, but their relevance for giving pertinent 3D information is unclear. Thirty-three calcaneus and femoral neck bone samples including the cortical shells (diameter: 14 mm, height: 30-40 mm) were imaged using 3D-synchrotron x-ray micro-CT at the ESRF. The 3D reconstructed images with a cubic voxel size of 15 {mu}m were further used for two purposes: (1) quantification of three-dimensional trabecular bone micro-architecture (2) simulation of realistic x-ray radiographs under different acquisition conditions. The simulated x-ray radiographs were then analyzed using a large variety of texture analysis methods (co-occurrence, spectral density, fractal, morphology, etc.). The range of micro-architecture parameters was in agreement with previous studies and rather large, suggesting that the population was representative. More than 350 texture parameters were tested. A small number of them were selected based on their correlation to micro-architectural morphometric parameters. Using this subset of texture parameters, multiple regression allowed one to predict up to 93% of the variance of micro-architecture parameters using three texture features. 2D texture features predicting 3D micro-architecture parameters other than BV/TV were identified. The methodology proposed for evaluating the relationships between 3D micro-architecture and 2D texture parameters may also be used for optimizing the conditions for radiographic imaging. Further work will include the application of the method to physical radiographs. In the future, this approach could be used in combination with DXA to refine osteoporosis diagnosis.

  12. Electronic system for digital acquisition of rotational panoramic radiographs

    SciTech Connect

    McDavid, W.D.; Dove, S.B.; Welander, U.; Tronje, G. )

    1991-04-01

    A prototype system for digital panoramic imaging of the maxillofacial complex has been developed. In this system x-ray film is replaced by an electronic sensor that delivers the image information to a computer for storage in digital format. The images, which are similar to conventional panoramic radiographs, are displayed on a high-resolution video monitor and may be stored on optical disk for future use. Hard-copy output is also available. The present prototype system has been installed on an Orthopantomograph model OP10 panoramic x-ray machine is programmed for operation with this machine, but in principle the system can be installed on any such device. The system may be incorporated into the design of future panoramic x-ray systems or may be used to retrofit panoramic x-ray systems now using photographic film to record the radiographic image. Greater sensitivity of electronic sensors should make possible a reduction of x-ray dose to the patient, compared with film-based systems.

  13. Digital radiographic localization for CT scanning of the larynx

    SciTech Connect

    Silverman, P.M.; Korobkin, M.; Rauch, R.F.

    1983-12-01

    Computed tomography (CT) of the larynx is the preferred method for staging laryngeal carcinoma and assessing the extent of injury from trauma. The standard method of examination consists of 5 mm contiguous scans throughout the larynx in quiet respiration. Scans are performed with the patient supine with the neck slightly extended allowing the long axis of the larynx to be perpendicular to the scanning plane. A complete examination requires scanning from the supraglottic region (level of hyoid bone) to the subglottic region (level of cricoid cartlage). In the authors' experience when this method is used, multiple scans are performed cephalad to the level of interest because no upper limit of the examination is established before transaxial scans are done. We have used the lateral digital radiograph of the neck to identify specific landmarks so that the upper and lower limets of the examination can be established before scanning.

  14. 42 CFR 37.51 - Interpreting and classifying chest radiographs-digital radiography systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-digital radiography systems. 37.51 Section 37.51 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH..., and Submission of Chest Radiographs § 37.51 Interpreting and classifying chest radiographs—digital radiography systems. (a) For each chest radiograph obtained at an approved facility using a...

  15. Radiographer.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is designed for use in developing a tech prep competency profile for the occupation of radiographer, lists technical competencies and competency builders for 18 units pertinent to the health technologies cluster in general as well as those specific to the occupation of radiographer. The following skill areas are covered in the…

  16. Comparison of digital breast tomosynthesis and 2D digital mammography using a hybrid performance test

    NASA Astrophysics Data System (ADS)

    Cockmartin, Lesley; Marshall, Nicholas W.; Van Ongeval, Chantal; Aerts, Gwen; Stalmans, Davina; Zanca, Federica; Shaheen, Eman; De Keyzer, Frederik; Dance, David R.; Young, Kenneth C.; Bosmans, Hilde

    2015-05-01

    This paper introduces a hybrid method for performing detection studies in projection image based modalities, based on image acquisitions of target objects and patients. The method was used to compare 2D mammography and digital breast tomosynthesis (DBT) in terms of the detection performance of spherical densities and microcalcifications. The method starts with the acquisition of spheres of different glandular equivalent densities and microcalcifications of different sizes immersed in a homogeneous breast tissue simulating medium. These target objects are then segmented and the subsequent templates are fused in projection images of patients and processed or reconstructed. This results in hybrid images with true mammographic anatomy and clinically relevant target objects, ready for use in observer studies. The detection study of spherical densities used 108 normal and 178 hybrid 2D and DBT images; 156 normal and 321 hybrid images were used for the microcalcifications. Seven observers scored the presence/absence of the spheres/microcalcifications in a square region via a 5-point confidence rating scale. Detection performance in 2D and DBT was compared via ROC analysis with sub-analyses for the density of the spheres, microcalcification size, breast thickness and z-position. The study was performed on a Siemens Inspiration tomosynthesis system using patient acquisitions with an average age of 58 years and an average breast thickness of 53 mm providing mean glandular doses of 1.06 mGy (2D) and 2.39 mGy (DBT). Study results showed that breast tomosynthesis (AUC = 0.973) outperformed 2D (AUC = 0.831) for the detection of spheres (p  <  0.0001) and this applied for all spherical densities and breast thicknesses. By way of contrast, DBT was worse than 2D for microcalcification detection (AUC2D = 0.974, AUCDBT = 0.838, p  <  0.0001), with significant differences found for all sizes (150-354 µm), for breast thicknesses above 40 mm and for heights

  17. Comparison of digital breast tomosynthesis and 2D digital mammography using a hybrid performance test.

    PubMed

    Cockmartin, Lesley; Marshall, Nicholas W; Van Ongeval, Chantal; Aerts, Gwen; Stalmans, Davina; Zanca, Federica; Shaheen, Eman; De Keyzer, Frederik; Dance, David R; Young, Kenneth C; Bosmans, Hilde

    2015-05-21

    This paper introduces a hybrid method for performing detection studies in projection image based modalities, based on image acquisitions of target objects and patients. The method was used to compare 2D mammography and digital breast tomosynthesis (DBT) in terms of the detection performance of spherical densities and microcalcifications. The method starts with the acquisition of spheres of different glandular equivalent densities and microcalcifications of different sizes immersed in a homogeneous breast tissue simulating medium. These target objects are then segmented and the subsequent templates are fused in projection images of patients and processed or reconstructed. This results in hybrid images with true mammographic anatomy and clinically relevant target objects, ready for use in observer studies. The detection study of spherical densities used 108 normal and 178 hybrid 2D and DBT images; 156 normal and 321 hybrid images were used for the microcalcifications. Seven observers scored the presence/absence of the spheres/microcalcifications in a square region via a 5-point confidence rating scale. Detection performance in 2D and DBT was compared via ROC analysis with sub-analyses for the density of the spheres, microcalcification size, breast thickness and z-position. The study was performed on a Siemens Inspiration tomosynthesis system using patient acquisitions with an average age of 58 years and an average breast thickness of 53 mm providing mean glandular doses of 1.06 mGy (2D) and 2.39 mGy (DBT). Study results showed that breast tomosynthesis (AUC = 0.973) outperformed 2D (AUC = 0.831) for the detection of spheres (p  <  0.0001) and this applied for all spherical densities and breast thicknesses. By way of contrast, DBT was worse than 2D for microcalcification detection (AUC2D = 0.974, AUCDBT = 0.838, p  <  0.0001), with significant differences found for all sizes (150-354 µm), for breast thicknesses above 40 mm and for heights

  18. A digitally reconstructed radiograph algorithm calculated from first principles

    SciTech Connect

    Staub, David; Murphy, Martin J.

    2013-01-15

    Purpose: To develop an algorithm for computing realistic digitally reconstructed radiographs (DRRs) that match real cone-beam CT (CBCT) projections with no artificial adjustments. Methods: The authors used measured attenuation data from cone-beam CT projection radiographs of different materials to obtain a function to convert CT number to linear attenuation coefficient (LAC). The effects of scatter, beam hardening, and veiling glare were first removed from the attenuation data. Using this conversion function the authors calculated the line integral of LAC through a CT along rays connecting the radiation source and detector pixels with a ray-tracing algorithm, producing raw DRRs. The effects of scatter, beam hardening, and veiling glare were then included in the DRRs through postprocessing. Results: The authors compared actual CBCT projections to DRRs produced with all corrections (scatter, beam hardening, and veiling glare) and to uncorrected DRRs. Algorithm accuracy was assessed through visual comparison of projections and DRRs, pixel intensity comparisons, intensity histogram comparisons, and correlation plots of DRR-to-projection pixel intensities. In general, the fully corrected algorithm provided a small but nontrivial improvement in accuracy over the uncorrected algorithm. The authors also investigated both measurement- and computation-based methods for determining the beam hardening correction, and found the computation-based method to be superior, as it accounted for nonuniform bowtie filter thickness. The authors benchmarked the algorithm for speed and found that it produced DRRs in about 0.35 s for full detector and CT resolution at a ray step-size of 0.5 mm. Conclusions: The authors have demonstrated a DRR algorithm calculated from first principles that accounts for scatter, beam hardening, and veiling glare in order to produce accurate DRRs. The algorithm is computationally efficient, making it a good candidate for iterative CT reconstruction techniques

  19. A digitally reconstructed radiograph algorithm calculated from first principles

    PubMed Central

    Staub, David; Murphy, Martin J.

    2013-01-01

    Purpose: To develop an algorithm for computing realistic digitally reconstructed radiographs (DRRs) that match real cone-beam CT (CBCT) projections with no artificial adjustments. Methods: The authors used measured attenuation data from cone-beam CT projection radiographs of different materials to obtain a function to convert CT number to linear attenuation coefficient (LAC). The effects of scatter, beam hardening, and veiling glare were first removed from the attenuation data. Using this conversion function the authors calculated the line integral of LAC through a CT along rays connecting the radiation source and detector pixels with a ray-tracing algorithm, producing raw DRRs. The effects of scatter, beam hardening, and veiling glare were then included in the DRRs through postprocessing. Results: The authors compared actual CBCT projections to DRRs produced with all corrections (scatter, beam hardening, and veiling glare) and to uncorrected DRRs. Algorithm accuracy was assessed through visual comparison of projections and DRRs, pixel intensity comparisons, intensity histogram comparisons, and correlation plots of DRR-to-projection pixel intensities. In general, the fully corrected algorithm provided a small but nontrivial improvement in accuracy over the uncorrected algorithm. The authors also investigated both measurement- and computation-based methods for determining the beam hardening correction, and found the computation-based method to be superior, as it accounted for nonuniform bowtie filter thickness. The authors benchmarked the algorithm for speed and found that it produced DRRs in about 0.35 s for full detector and CT resolution at a ray step-size of 0.5 mm. Conclusions: The authors have demonstrated a DRR algorithm calculated from first principles that accounts for scatter, beam hardening, and veiling glare in order to produce accurate DRRs. The algorithm is computationally efficient, making it a good candidate for iterative CT reconstruction techniques

  20. Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

    NASA Astrophysics Data System (ADS)

    Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

    2016-03-01

    In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

  1. Ex vivo evaluation of new 2D and 3D dental radiographic technology for detecting caries

    PubMed Central

    Tyndall, Donald; Mol, André; Everett, Eric T; Bangdiwala, Ananta

    2016-01-01

    Objectives: Proximal dental caries remains a prevalent disease with only modest detection rates by current diagnostic systems. Many new systems are available without controlled validation of diagnostic efficacy. The objective of this study was to evaluate the diagnostic efficacy of three potentially promising new imaging systems. Methods: This study evaluated the caries detection efficacy of Schick 33 (Sirona Dental, Salzburg, Austria) intraoral digital detector images employing an advanced sharpening filter, Planmeca ProMax® (Planmeca Inc., Helsinki, Finland) extraoral “panoramic bitewing” images and Sirona Orthophos XG3D (Sirona Dental) CBCT images with advanced artefact reduction. Conventional photostimulable phosphor images served as the control modality. An ex vivo study design using extracted human teeth, ten expert observers and micro-CT ground truth was employed. Results: Receiver operating characteristic analysis indicated similar diagnostic efficacy of all systems (ANOVA p > 0.05). The sensitivity of the Schick 33 images (0.48) was significantly lower than the other modalities (0.53–0.62). The specificity of the Planmeca images (0.86) was significantly lower than Schick 33 (0.96) and XG3D (0.97). The XG3D showed significantly better cavitation detection sensitivity (0.62) than the other modalities (0.48–0.57). Conclusions: The Schick 33 images demonstrated reduced caries sensitivity, whereas the Planmeca panoramic bitewing images demonstrated reduced specificity. XG3D with artefact reduction demonstrated elevated sensitivity and specificity for caries detection, improved depth accuracy and substantially improved cavitation detection. Care must be taken to recognize potential false-positive caries lesions with Planmeca panoramic bitewing images. Use of CBCT for caries detection must be carefully balanced with the presence of metal artefacts, time commitment, financial cost and radiation dose. PMID:26670605

  2. Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study.

    PubMed

    Manning, J T; Peters, M

    2009-09-01

    The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths. We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference). A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.

  3. Comparison between inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements.

    PubMed

    Scaf, Gulnara; Morihisa, Olívia; Loffredo, Leonor de Castro Monteiro

    2007-12-01

    The advances in digital imaging technology in dentistry have provided an alternative to film-based radiography and have given new options to detect periodontal bone loss. The purpose of this study was to compare inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements. Thirty-five film-based periapical radiographs of patients suffering from moderate to advanced untreated periodontal bone loss associated to lower premolar and molars was selected from the department files, with 40 bone loss areas. The film-based radiographs were digitized with a flatbed scanner with a transparency and radiograph adapter used for transilluminating the radiograph imaging. Digitization was performed at 600 dpi and in gray scale. The images were digitized using Image Tool software by applying image inversion, that is, transformation of radiopaque structures into radiolucent structures and vice-versa. The digital data were saved as JPEG files. The images were displayed on a 15-inch and 24-bit video monitor under reduced room lighting. One calibrated examiner performed all radiographic measurements, three times, from the cementoenamel junction to the most apical extension of the bone loss, in both types of image (inverted and unprocessed). Brightness and contrast were adjusted according to the examiner's individual demand. Intraclass correlation coefficient was used to compare the measurements from both types of images. The means of radiographic measurements, in mm, for inverted and unprocessed digitized imaging were 6.4485 and 6.3790, respectively. The intraclass correlation coefficient was significant (0.99) The inverted and unprocessed digitized radiographic images were reliable and there was no difference in the diagnostic accuracy between these images regarding periodontal bone loss measurements.

  4. Radiographic determination of canal length direct digital radiography versus conventional radiography.

    PubMed

    Hedrick, R T; Dove, S B; Peters, D D; McDavid, W D

    1994-07-01

    This research compared the length determination images produced by Trophy and Regam direct digital radiographic systems with conventional E-speed radiographs. Size #15 K files were placed in the canals of 19 teeth of cadaver specimens and radiographed in a geometrically standardized bench device. Three evaluators estimated the length adjustment necessary to position the file at the apex. The mean estimated adjustment lengths were compared with the true, anatomically determined adjustment lengths. Statistical analysis with analysis of variance and the Student-Newman-Keuls test indicated no significant difference between direct digital thermal print images and conventional radiographs (p > 0.10). Length adjustment estimates with conventional radiographs were significantly more accurate than Regam high-resolution computer monitor images (p < 0.01). Additionally, it was determined that length adjustment estimates were significantly more accurate when the file was placed short of the apex (p < 0.001). The clinical relevance of these differences is discussed.

  5. COMPARISON OF RADIOGRAPHIC MEASUREMENTS OBTAINED WITH CONVENTIONAL AND INDIRECT DIGITAL IMAGING DURING ENDODONTIC TREATMENT

    PubMed Central

    Schmitd, Ligia Buloto; Lima, Tatiana de Castro; Chinellato, Luiz Eduardo Montenegro; Bramante, Clóvis Monteiro; Garcia, Roberto Brandão; de Moraes, Ivaldo Gomes; Bernardineli, Norberti

    2008-01-01

    The aims of this study were to evaluate the quality of indirect digitized radiographic images taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitized images were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitized images were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographic images, all indirect digitized images were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (p<0.01). The measurements achieved by the investigated radiographic methods were clinically similar and they are thus equivalent. Changes in brightness and contrast of the images using Digora® software improved the diagnosis. PMID:19089211

  6. Digital spall radiograph analysis system: Report on simulated three- dimensional digital spall image reconstruction fidelity

    SciTech Connect

    Harris, C.L.

    1990-01-01

    This report describes progress on work to develop a cost effective, rapid response system for measuring momentum and kinetic energy of spall for the Advanced Technology Assessment Center (ATAC) Armor/Anti-Armor (A{sup 3}) program at Los Alamos National Laboratory. The system will exploit data contained in two sets of simultaneous co-planar flash radiographs taken along the center line of anticipated spall motion. Data contained in each set (which is proportional to the mass and z- number of the spall material intersected by the exposing x-ray at each point) is digitized and used to construct a three dimensional model (called the reconstructed spall image) that approximates the original spall cloud. From the model the mass of spall fragments is computed. The two sets of radiographs, separated in time, represent the spall configuration at two instants of time. Spall fragments from the first instant are matched with those from the second instant to determine velocity. Evaluation of the fidelity of candidate reconstruction algorithms is the highest priority task in this development program for the obvious reason that the efficacy of the projected spall analysis system depends upon the fidelity of the reconstruction techniques. The purpose of this document is to report the results of analysis of the fidelity of best reconstruction procedure (for one radiograph set) investigated to date. The reconstruction procedure uses data from four simultaneous radiographs representing two sides and two diagonals of a cube. The procedure makes use of an available space algorithm, two probabilistic devices (a mass placement probability heuristic, and a mass clumping heuristic), and a stochastic procedure for mass that cannot be placed by the algorithm or either of the heuristics. The procedure is fully described in the body of the report.

  7. The Relationship Between Digit Ratio (2D:4D) and Sexual Orientation in Men from China.

    PubMed

    Xu, Yin; Zheng, Yong

    2016-04-01

    We examined the relationship between 2D:4D digit ratio and sexual orientation in men from China and analyzed the influences of the components used to assess sexual orientation and the criteria used to classify individuals as homosexual on this relationship. A total of 309 male and 110 female participants took part in a web-based survey. Our results showed that heterosexual men had a significantly lower 2D:4D than heterosexual women and exclusively homosexual men had a significantly higher left 2D:4D than heterosexual men whereas only exclusively homosexual men had a significantly higher right 2D:4D than heterosexual men when sexual orientation was assessed via sexual attraction. The left 2D:4D showed a significant positive correlation with sexual identity, sexual attraction, and sexual behavior, and the right 2D:4D showed a significant positive correlation with sexual attraction. The effect sizes for differences in 2D:4D between homosexual and heterosexual men varied according to criteria used to classify individuals as homosexual and sexual orientation components; the more stringent the criteria (scores closer to the homosexual category), the larger the effect sizes; further, sexual attraction yielded the largest effect size. There were no significant effects of age and latitude on Chinese 2D:4D. This study contributes to the current understanding of the relationship between 2D:4D and male sexual orientation.

  8. Brazilian young dental practitioners' use and acceptance of digital radiographic examinations

    PubMed Central

    de Faria Vasconcelos, Karla; do Nascimento, Eduarda Helena Leandro; Oliveira, Matheus Lima; Freitas, Deborah Queiroz; Haiter-Neto, Francisco

    2016-01-01

    Purpose The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. Materials and Methods Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). Results A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. Conclusion This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations. PMID:28035301

  9. Common Errors in Digital Panoramic Radiographs of Patients with Mixed Dentition and Patients with Permanent Dentition

    PubMed Central

    Peretz, Benjamin; Gotler, Maya; Kaffe, Israel

    2012-01-01

    Purpose. To compare errors in digital panoramic radiographs of permanent and mixed dentitions. Methods. 143 and 146 digital radiographs of mixed and permanent dentitions were examined. Results. Significantly fewer errors presented in the mixed dentition. Positioning too forward significantly prevalent in the mixed dentition; slumped position and nonpositioning of chin properly were significantly prevailed in the permanent dentition. Blurred or shortened upper incisors were significantly more prevalent in the mixed dentition. Diagnostic ability could be improved by manipulating the brightness or contrast in nearly 45% of all radiographs. In the mixed dentition, tilting the chin down and a slumped position made the lower incisors significantly nondiagnostic. In the permanent dentition, tilting the chin down made the lower incisors to be significantly nondiagnostic. Conclusions. More errors were prevalent in panoramic radiographs of permanent dentitions. Properly positioning the patient is the most important factor in preventing a cascade of errors. PMID:22505905

  10. Radiographical assessment of interphalangeal rotation in the evaluation of equine digital conformation.

    PubMed

    Caudron, I; Grülke, S; Gabriel, A; Serteyn, D

    1997-01-01

    This study is a part of a work to design a radiographical method to objectively define the conformation of an equine digit and to assess the individual appropriate trimming of a horse. Various angles were measured directly from the phalangeal bones. The authors observed that the bone relief of the sesamoid ligament insertions on the proximal phalanx was an essential landmark to determine the phalangeal alignment. The same angles were measured from specific radiographs and made it possible to quantify the rotation imposed to the proximal phalanx. The authors also noticed that the phalangeal rotation had little influence on the radiographic image of articular asymmetry.

  11. Comparison of radiographic image quality from four digitization devices as viewed on computer monitors.

    PubMed

    Davidson, H C; Johnston, D J; Christian, M E; Harnsberger, H R

    2001-03-01

    The objective of this study was to compare the quality of radiographic images digitized from commercial-grade and consumer-grade digital cameras and scanners as viewed on computer monitor. Radiographic images were digitized from hardcopy film using a commercial-grade laser scanner, a consumer-grade desktop flatbed scanner, a commercial-grade digital camera, and a consumer-grade digital camera. The quality of images without and with grayscale histogram adjustment was evaluated subjectively by 10 board-certified radiologists. Optical density response was evaluated objectively using a grayscale test pattern. There was no significant difference in subjective quality among images digitized with the commercial scanner, consumer scanner, and commercial camera. The quality of images digitized with the consumer camera was lower than the other 3. Objective tests showed the commercial scanner to have the most linear optical density response. For the purpose of viewing images on a computer monitor, a consumer-grade desktop scanner can produce images of similar quality to those produced by more expensive laser commercial-grade scanners and digital cameras and provides cost-efficient means to digitize radiographic plain films. A consumer-grade camera may not be optimal for use in this setting.

  12. Effects of Cognitive Styles on 2D Drafting and Design Performance in Digital Media

    ERIC Educational Resources Information Center

    Pektas, Sule Tasli

    2010-01-01

    This paper investigates the interactions between design students' cognitive styles, as measured by Riding's Cognitive Styles Analysis, and performance in 2D drafting and design tasks in digital media. An empirical research revealed that Imager students outperformed Verbalisers in both drafting and creativity scores. Wholist-Analytic cognitive…

  13. Readability of cervical spine imaging: digital versus film/screen radiographs.

    PubMed

    Kreipke, D L; Silver, D I; Tarver, R D; Braunstein, E M

    1990-01-01

    In 109 trauma patients, both film/screen and digital lateral cervical spine radiographs were obtained. These films were compared for adequate visualization ("readability") of bone, soft tissue, and airway, and lowest visualized cervical vertebra. With viewbox alone, digital adequately demonstrated bone, soft tissue, and airway more often than film/screen. With a hotlight, there was no significant difference between digital and film/screen in adequately demonstrating bone, but for soft tissue and airway definition, digital was significantly better. There was less interobserver and intraobserver variation on digital than in film/screen. There was no significant difference in lowest vertebra identified.

  14. Is digit ratio (2D:4D) a reliable pointer to speech laterality?

    PubMed

    Hudson, John M; Hodgson, Jessica C

    2016-03-15

    The relative length of the second and fourth digits (2D:4D ratio) is sexually dimorphic and a retrospective biomarker of prenatal hormonal exposure. Low ratios indicate higher prenatal testosterone (pT) and lower estrogen exposure, whereas the reverse pattern is associated with high ratios. Elevated levels of pT exposure have long been thought to modulate hemispheric specialisation; subsequently many studies use the 2D:4D ratio as a proxy index for pT to examine the effects of prenatal hormonal exposure on lateralised cognitive abilities. Here we used Transcranial Doppler ultrasonography and digit ratio to investigate whether pT has an influence on speech laterality. We tested 34 right and 14 left handed adults. Our results indicate that speech representation is unrelated to digit characteristics and therefore purportedly pT. We discuss these findings in relation to androgen theories of lateralisation.

  15. Application of Perona Malik anisotropic diffusion on digital radiographic image

    NASA Astrophysics Data System (ADS)

    Halim, Suhaila Abd; Razak, Rohayu Abdul; Ibrahim, Arsmah; Manurung, Yupiter HP

    2014-07-01

    Perona Malik Anisotropic Diffusion (PMAD) is a very useful and efficient denoising technique if the parameters are properly selected. Overestimating the parameters may cause oversmoothed and underestimating it may leave unfiltered noise. This makes the selection of parameters a crucial process. In this paper the PMAD model is solved using a finite difference scheme The discretized model is evaluated using different diffusion coefficient of exponential and quadratic on defective radiographic images in terms of quality and efficiency. In the application of the PMAD model on image data, a set of defective radiographic images of welding is used as input data. Peak Signal to Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and temporal time are used to evaluate the performance of the model. The implementation of the experiment has been carried out using MATLAB R2009a. In terms of quality, results show that the Quadratic Diffusion Coefficient Function (QDCF) provides better results compared with the Exponential Diffusion Coefficient Function (EDCF). In conclusion, the denoising effect using PMAD model based on finite difference scheme shows able to improve image quality by removing noise in the defective radiographic image.

  16. Application of Perona Malik anisotropic diffusion on digital radiographic image

    SciTech Connect

    Halim, Suhaila Abd; Razak, Rohayu Abdul; Ibrahim, Arsmah; Manurung, Yupiter HP

    2014-07-10

    Perona Malik Anisotropic Diffusion (PMAD) is a very useful and efficient denoising technique if the parameters are properly selected. Overestimating the parameters may cause oversmoothed and underestimating it may leave unfiltered noise. This makes the selection of parameters a crucial process. In this paper the PMAD model is solved using a finite difference scheme The discretized model is evaluated using different diffusion coefficient of exponential and quadratic on defective radiographic images in terms of quality and efficiency. In the application of the PMAD model on image data, a set of defective radiographic images of welding is used as input data. Peak Signal to Noise Ratio (PSNR), Structural Similarity Measure (SSIM) and temporal time are used to evaluate the performance of the model. The implementation of the experiment has been carried out using MATLAB R2009a. In terms of quality, results show that the Quadratic Diffusion Coefficient Function (QDCF) provides better results compared with the Exponential Diffusion Coefficient Function (EDCF). In conclusion, the denoising effect using PMAD model based on finite difference scheme shows able to improve image quality by removing noise in the defective radiographic image.

  17. Digit ratio (2D:4D), lateral preferences, and performance in fencing.

    PubMed

    Voracek, Martin; Reimer, Barbara; Ertl, Clara; Dressler, Stefan G

    2006-10-01

    The second to fourth digit ratio (2D:4D) is a sexually dimorphic trait (men tend to have lower values than women) and a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. Prenatal testosterone, as reflected by 2D:4D, has many extragenital effects, including its relevance for the formation of an efficient cardiovascular system. Previous research, reviewed here, has therefore investigated possible associations of 2D:4D with sport performance. Several studies found more masculinized digit ratio patterns (low 2D:4D values or a negative right-minus-left difference in 2D:4D) to be related to high performance in running, soccer, and skiing. The present research tested this hypothesis in a sample of 54 tournament fencers, predominantly from Austria. For men, negative right-left differences in 2D:4D corresponded significantly to better current as well as highest national fencing rankings, independent of training intensity and fencing experience. The mean 2D:4D values of these fencers were significantly lower and the proportion of left-handers was elevated relative to the local general population. For the right hand, the ratio was somewhat lower in male sabre fencers than in male epée and foil fencers combined and significantly lower in left-handed compared to right-handed fencers. Although nonsignificant due to low statistical power, effect sizes suggested that crossed versus congruent hand-eye and hand-foot preferences might also be related to fencing performance. The present findings add to the evidence that 2D:4D might be a performance indicator for men across a variety of sports.

  18. Scientometric analysis and bibliography of digit ratio (2D:4D) research, 1998-2008.

    PubMed

    Voracek, Martin; Loibl, Lisa Mariella

    2009-06-01

    A scientometric analysis of modern research on the second-to-fourth digit ratio (2D:4D), a widely studied putative marker for prenatal androgen action, is presented. In early 2009, this literature totalled more than 300 publications and, since its initiation in 1998, has grown at a rate slightly faster than linear. Key findings included evidence of publication bias and citation bias, incomplete coverage and outdatedness of existing reviews, and a dearth of meta-analyses in this field. 2D:4D research clusters noticeably in terms of researchers, institutions, countries, and journals involved. Although 2D:4D is an anthropometric trait, most of the research has been conducted at psychology departments, not anthropology departments. However, 2D:4D research has not been predominantly published in core and specialized journals of psychology, but rather in more broadly scoped journals of the behavioral sciences, biomedical social sciences, and neurosciences. Total citation numbers of 2D:4D papers for the most part were not larger than their citation counts within 2D:4D research, indicating that until now, only a few 2D:4D studies have attained broader interest outside this specific field. Comparative citation analyses show that 2D:4D research presently is commensurate in size and importance to evolutionary psychological jealousy research, but has grown faster than the latter field. In contrast, it is much smaller and has spread more slowly than research about the Implicit Association Test Fifteen conjectures about anticipated trends in 2D:4D research are outlined, appendixed by a first-time bibliography of the entirety of the published 2D:4D literature.

  19. Morphometric Comparison of Clavicle Outlines from 3D Bone Scans and 2D Chest Radiographs: A Short-listing Tool to Assist Radiographic Identification of Human Skeletons

    SciTech Connect

    Stephan, Carl N.; Amidan, Brett G.; Trease, Harold E.; Guyomarch, Pierre; Pulsipher, Trenton C.; Byrd, John E.

    2014-03-01

    This paper describes a computerized clavicle identification system, primarily designed to resolve the identities of unaccounted for US soldiers who fought in the Korean War. Elliptical Fourier analysis is used to quantify the clavicle outline shape from skeletons and postero-anterior antemortem chest radiographs to rank individuals in terms of metric distance. Similar to leading fingerprint identification systems, shortlists of the top matching candidates are extracted for subsequent human visual assessment. Two independent tests of the computerized system using 17 field-recovered skeletons and 409 chest radiographs demonstrate that true positive matches are captured within the top 5% of the sample 75% of the time. These results are outstanding given the eroded state of some field-recovered skeletons and the faintness of the 1950’s photoflurographs. These methods enhance the capability to resolve several hundred cold cases for which little circumstantial information exists and current DNA and dental record technologies cannot be applied.

  20. [The imaging principles and the structure of the low-dose digital radiographic device].

    PubMed

    Kang, Q Z; Yu, H L; Zhang, H; Zhang, D S; Cao, H D

    2001-03-01

    This article introduced A new type of X-ray radiographic device, which uses MWPC as the low-dose detector with the machinery and computer to reconstruct the X-ray digital images. In this paper, the advantages and the disadvantages of the device are analysed, thus much improvement has been made to make it better and more efficient.

  1. Digital phase-stepping holographic interferometry in measuring 2-D density fields

    NASA Astrophysics Data System (ADS)

    Lanen, T. A. W. M.; Nebbeling, C.; van Ingen, J. L.

    1990-06-01

    This paper presents a holographic interferometer technique for measuring transparent (2-D or quasi 2-D) density fields. To be able to study the realization of such a field at a certain moment of time, the field is “frozen” on a holographic plate. During the reconstruction of the density field from the hologram the length of the path traversed by the reconstruction beam is diminished in equal steps by applying a computer controlled voltage to a piezo-electric crystal that translates a mirror. Four phase-stepped interferograms resulting from this pathlength variation are digitized and serve as input to an algorithm for computing the phase surface. The method is illustrated by measuring the basically 2-D density field existing around a heated horizontal cylinder in free convection.

  2. A multiple digital watermarking algorithm based on 1D and 2D chaotic sequences

    NASA Astrophysics Data System (ADS)

    Ji, Zhen; Jiang, Lai; Jin, Jing; Zhang, Jihong

    2003-09-01

    Multiple digital watermarking is attracting more and more researchers because it is more valuable in the practical applications than single watermarking. In this paper, a multiple watermarking algorithm based on 1-D and 2-D chaotic sequences is proposed. The chaotic sequences have the advantages of massive, high security, and weakest correlation. The massive and independent digital watermark signals are generated through 1-D chaotic maps, which are determined by different initial conditions and parameters. The chaotic digital watermark signals effectively resolve the construction of massive watermarks with good performance. The embedding of multiple watermakrs is more complex than the single watermarking scheme. In this paper, each watermark is added to the middle frequency coefficients of wavelet domain randomly by exploiting 2-D chaotic system, so the embedding and extracting of each watermark would not disturb each other. Considering the parameters of 2-D chaotic systsem as the key to embedding procedure can prevent the watermarks to be removed maliciously, therefore the performance of security is better. The capacity of the multiple watermarking is also analyzed in this paper. The experimental results demonstrate that this proposed watermarking algorithm is robust to many common attacks and it is a reliable copyright protection for multiple legal owners.

  3. The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis

    SciTech Connect

    Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde

    2011-12-15

    Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated

  4. Prediction of age and gender using digital radiographic method: A retrospective study

    PubMed Central

    Poongodi, V.; Kanmani, R.; Anandi, M. S.; Krithika, C. L.; Kannan, A.; Raghuram, P. H.

    2015-01-01

    Aim and Objective: To investigate age, sex based on gonial angle, width and breadth of the ramus of the mandible by digital orthopantomograph. Materials and Methods: A total of 200 panoramic radiographic images were selected. The age of the individuals ranged between 4 and 75 years of both the gender - males (113) and females (87) and selected radiographic images were measured using KLONK image measurement software tool with linear, angular measurement. The investigated radiographs were collected from the records of SRM Dental College, Department of Oral Medicine and Radiology. Radiographs with any pathology, facial deformities, if no observation of mental foramen, congenital deformities, magnification, and distortion were excluded. Results: Mean, median, standard deviation, derived to check the first and third quartile, linear regression is used to check age and gender correlation with angle of mandible, height and width of the ramus of mandible. Conclusion: The radiographic method is a simpler and cost-effective method of age identification compared with histological and biochemical methods. Mandible is strongest facial bone after the skull, pelvic bone. It is validatory to predict age and gender by many previous studies. Radiographic and tomographic images have become an essential aid for human identification in forensic dentistry forensic dentists can choose the most appropriate one since the validity of age and gender estimation crucially depends on the method used and its proper application. PMID:26538907

  5. A Pascal computer program for digitizing lateral cephalometric radiographs.

    PubMed

    Konchak, P A; Koehler, J A

    1985-03-01

    The authors describe a new program for cephalometric analysis which uses a commonly available microprocessor (computer) and digitizing pad to register fifteen commonly identified cephalometric landmarks to produce a meaningful analysis which is printed out for permanent or hard-copy record. Conventional and digitizing errors of cephalometric measurement are reviewed, with a discussion of the advantages of computer-assisted programs. The authors describe a program that uses vectors and vector algebra and the capabilities of the Pascal computer language to determine angular measurements and distances. It is suggested that computer-assisted cephalometric programs will likely be widely used in the near future, providing the orthodontist with a superior method of cephalometric analysis with respect to accuracy and speed of completion.

  6. The simulation of 3D mass models in 2D digital mammography and breast tomosynthesis

    SciTech Connect

    Shaheen, Eman De Keyzer, Frederik; Bosmans, Hilde; Ongeval, Chantal Van; Dance, David R.; Young, Kenneth C.

    2014-08-15

    Purpose: This work proposes a new method of building 3D breast mass models with different morphological shapes and describes the validation of the realism of their appearance after simulation into 2D digital mammograms and breast tomosynthesis images. Methods: Twenty-five contrast enhanced MRI breast lesions were collected and each mass was manually segmented in the three orthogonal views: sagittal, coronal, and transversal. The segmented models were combined, resampled to have isotropic voxel sizes, triangularly meshed, and scaled to different sizes. These masses were referred to as nonspiculated masses and were then used as nuclei onto which spicules were grown with an iterative branching algorithm forming a total of 30 spiculated masses. These 55 mass models were projected into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. The realism of the appearance of these mass models was assessed by five radiologists via receiver operating characteristic (ROC) analysis when compared to 54 real masses. All lesions were also given a breast imaging reporting and data system (BIRADS) score. The data sets of 2D mammography and tomosynthesis were read separately. The Kendall's coefficient of concordance was used for the interrater observer agreement assessment for the BIRADS scores per modality. Further paired analysis, using the Wilcoxon signed rank test, of the BIRADS assessment between 2D and tomosynthesis was separately performed for the real masses and for the simulated masses. Results: The area under the ROC curves, averaged over all observers, was 0.54 (95% confidence interval [0.50, 0.66]) for the 2D study, and 0.67 (95% confidence interval [0.55, 0.79]) for the tomosynthesis study. According to the BIRADS scores, the nonspiculated and the spiculated masses varied in their degrees of malignancy from normal (BIRADS 1) to highly

  7. Linear Calibration of Radiographic Mineral Density Using Video-Digitizing Methods

    NASA Technical Reports Server (NTRS)

    Martin, R. Bruce; Papamichos, Thomas; Dannucci, Greg A.

    1990-01-01

    Radiographic images can provide quantitative as well as qualitative information if they are subjected to densitometric analysis. Using modern video-digitizing techniques, such densitometry can be readily accomplished using relatively inexpensive computer systems. However, such analyses are made more difficult by the fact that the density values read from the radiograph have a complex, nonlinear relationship to bone mineral content. This article derives the relationship between these variables from the nature of the intermediate physical processes, and presents a simple mathematical method for obtaining a linear calibration function using a step wedge or other standard.

  8. Linear Calibration of Radiographic Mineral Density Using Video-Digitizing Methods

    NASA Technical Reports Server (NTRS)

    Martin, R. Bruce; Papamichos, Thomas; Dannucci, Greg A.

    1990-01-01

    Radiographic images can provide quantitative as well as qualitative information if they are subjected to densitometric analysis. Using modem video-digitizing techniques, such densitometry can be readily accomplished using relatively inexpensive computer systems. However, such analyses are made more difficult by the fact that the density values read from the radiograph have a complex, nonlinear relationship to bone mineral content. This article derives the relationship between these variables from the nature of the intermediate physical processes, and presents a simple mathematical method for obtaining a linear calibration function using a step wedge or other standard.

  9. A comparison of 2D and 3D digital image correlation for a membrane under inflation

    PubMed Central

    Murienne, Barbara J.; Nguyen, Thao D.

    2015-01-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions. PMID:26543296

  10. A comparison of 2D and 3D digital image correlation for a membrane under inflation.

    PubMed

    Murienne, Barbara J; Nguyen, Thao D

    2016-02-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions.

  11. A comparison of 2D and 3D digital image correlation for a membrane under inflation

    NASA Astrophysics Data System (ADS)

    Murienne, Barbara J.; Nguyen, Thao D.

    2016-02-01

    Three-dimensional (3D) digital image correlation (DIC) is becoming widely used to characterize the behavior of structures undergoing 3D deformations. However, the use of 3D-DIC can be challenging under certain conditions, such as high magnification, and therefore small depth of field, or a highly controlled environment with limited access for two-angled cameras. The purpose of this study is to compare 2D-DIC and 3D-DIC for the same inflation experiment and evaluate whether 2D-DIC can be used when conditions discourage the use of a stereo-vision system. A latex membrane was inflated vertically to 5.41 kPa (reference pressure), then to 7.87 kPa (deformed pressure). A two-camera stereo-vision system acquired top-down images of the membrane, while a single camera system simultaneously recorded images of the membrane in profile. 2D-DIC and 3D-DIC were used to calculate horizontal (in the membrane plane) and vertical (out of the membrane plane) displacements, and meridional strain. Under static conditions, the baseline uncertainty in horizontal displacement and strain were smaller for 3D-DIC than 2D-DIC. However, the opposite was observed for the vertical displacement, for which 2D-DIC had a smaller baseline uncertainty. The baseline absolute error in vertical displacement and strain were similar for both DIC methods, but it was larger for 2D-DIC than 3D-DIC for the horizontal displacement. Under inflation, the variability in the measurements were larger than under static conditions for both DIC methods. 2D-DIC showed a smaller variability in displacements than 3D-DIC, especially for the vertical displacement, but a similar strain uncertainty. The absolute difference in the average displacements and strain between 3D-DIC and 2D-DIC were in the range of the 3D-DIC variability. Those findings suggest that 2D-DIC might be used as an alternative to 3D-DIC to study the inflation response of materials under certain conditions.

  12. Hip2Norm: an object-oriented cross-platform program for 3D analysis of hip joint morphology using 2D pelvic radiographs.

    PubMed

    Zheng, G; Tannast, M; Anderegg, C; Siebenrock, K A; Langlotz, F

    2007-07-01

    We developed an object-oriented cross-platform program to perform three-dimensional (3D) analysis of hip joint morphology using two-dimensional (2D) anteroposterior (AP) pelvic radiographs. Landmarks extracted from 2D AP pelvic radiographs and optionally an additional lateral pelvic X-ray were combined with a cone beam projection model to reconstruct 3D hip joints. Since individual pelvic orientation can vary considerably, a method for standardizing pelvic orientation was implemented to determine the absolute tilt/rotation. The evaluation of anatomically morphologic differences was achieved by reconstructing the projected acetabular rim and the measured hip parameters as if obtained in a standardized neutral orientation. The program had been successfully used to interactively objectify acetabular version in hips with femoro-acetabular impingement or developmental dysplasia. Hip(2)Norm is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway) for graphical user interface (GUI) and is transportable to any platform.

  13. Radiopacity evaluation of Portland and MTA-based cements by digital radiographic system

    PubMed Central

    BORGES, Alvaro Henrique; PEDRO, Fabio Luiz Miranda; SEMANOFF-SEGUNDO, Alex; MIRANDA, Carlos Eduardo Saraiva; PÉCORA, Jesus Djalma; CRUZ FILHO, Antônio Miranda

    2011-01-01

    Objective The aim of the present study was to evaluate the radiopacity of Portland and MTA-based cements using the Digora TM digital radiographic system. Material and Methods The performed tests followed specification number 57 from the American National Standard Institute/American Dental Association (2000) for endodontic sealing materials. The materials were placed in 5 acrylic plates, especially designed for this experiment, along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The set was radiographed at a 30 cm focus-object distance and with 0.2 s exposure time. After the radiographs were taken, the optical laser readings of radiographs were performed by Digora TM system. Five radiographic density readings were performed for each studied material and for each step of the aluminum scale. Results White ProRoot MTA (155.99±8.04), gray ProRoot MTA (155.96±16.30) and MTA BIO (143.13±16.94) presented higher radiopacity values (p<0.05), while white non-structural Portland (119.76±22.34), gray Portland (109.71±4.90) and white structural Portland (99.59±12.88) presented lower radiopacity values (p<0.05). Conclusions It was concluded that MTA-based cements were the only materials presenting radiopacity within the ANSI/ADA specifications. PMID:21625738

  14. Foreground marker controlled watershed on digital radiographic image for weld discontinuity detection

    NASA Astrophysics Data System (ADS)

    Abd Halim, Suhaila; Zahid, Akhma; Abdul Razak, Nurul Syafinaz; Ibrahim, Arsmah; Manurung, Yupiter HP; Jayes, Mohd Idris

    2013-04-01

    Radiography is one of the most common and widely used non-destructive testing (NDT) technique in inspecting weld discontinuity in welded joints. Conventionally, radiography inspector is requires to do the inspection analysis manually on weld discontinuity based on visual characteristics such as location, shape, length and density. The results can be very subjective, time consuming and inconsistent. Hence, semi-automated inspection using digital image processing and segmentation technique can be applied for weld discontinuity detection. The goal of this work is to detect the weld discontinuity on digital radiographic image using Foreground Marker Controlled Watershed. It is usually implemented in image processing because it always generates closed contour for each region in the image. In this paper, image enhancement on radiographic image is aim to remove image noise and improve image contrast. Then, marker controlled watershed with foreground markers is applied on the image to detect the discontinuity. The accuracy of the technique is evaluated using Receiver Operating Characteristic (ROC) curve. The accuracy of the technique has been compared with the ground truth and the result shows that the accuracy is 67% and area under the curve is 0.7134. The application of image processing technique in detecting weld discontinuity is able to assist radiographer to improve the inconsistent results in evaluating the radiographic image.

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  16. [Conventional radiology, digital radiology with photostimulable phosphor, laser digitalization of thoracic radiographic films at the bedside. A comparative study].

    PubMed

    Miceli, M; Stamati, R; Burci, P; Guidarelli, G; Sartoni Galloni, S

    1992-10-01

    The bedside chest images obtained with conventional radiology and with "on line" and "off line" digital modalities were compared to evaluate the respective capabilities in visualizing chest anatomical structures. Seventy patients were submitted to bedside chest examinations with a portable unit; both a conventional film and a digital system (PCR Graphics 1, Philips) with photostimulable phosphor imaging plate were fitted in the radiographic cassette. The former was digitized using an "off line" laser beam unit (FD 2000, Dupont); the latter was subsequently postprocessed by modifying contrast, optical density and spatial frequencies. Thus, 4 different viewing modalities were obtained for each examination: a) conventional radiography; b) standard digital radiography; c) postprocessed digital radiography; d) digitized conventional radiography. Detectability rates of chest anatomical structures were analyzed by 4 independent radiologists on the different images and expressed by a score 1-4. The values were always higher with digital modalities than with the conventional one and the differences were statistically significant (Student's t-test modified by Bonferroni). In particular, the greatest difference was found between c) and a) in retrocardiac lung parenchyma and in skeletal structures, in favour of c). Concerning the comparative adequacy of the various digital modalities, higher detectability rates of chest anatomical structures were obtained with c), but also with b), than with d).

  17. The use of digital periapical radiographs to study the prevalence of alveolar domes

    PubMed Central

    Xambre, Pedro Augusto Oliveira Santos; Valerio, Claudia Scigliano; e Alves Cardoso, Claudia Assunção; Custódio, Antônio Luís Neto

    2016-01-01

    Purpose In the present study, we coined the term 'alveolar dome' and aimed to demonstrate the prevalence of alveolar domes through digital periapical radiographs. Materials and Methods This study examined 800 digital periapical radiographs in regard to the presence of alveolar domes. The periapical radiographs were acquired by a digital system using a photostimulable phosphor (PSP) plate. The χ2 test, with a significance level of 5%, was used to compare the prevalence of alveolar domes in the maxillary posterior teeth and, considering the same teeth, to verify the difference in the prevalence of dome-shaped phenomena between the roots. Results The prevalence of alveolar domes present in the first pre-molars was statistically lower as compared to the other maxillary posterior teeth (p<0.05). No statistically significant difference was observed in the prevalence of alveolar domes between the maxillary first and second molars. Considering the maxillary first and second molars, it was observed that the palatal root presented a lower prevalence of alveolar domes when compared to the distobuccal and mesiobuccal roots (p<0.05). Conclusion The present study coined the term 'alveolar dome', referring to the anatomical projection of the root into the floor of the maxillary sinus. The maxillary first and second molars presented a greater prevalence of alveolar domes, especially in the buccal roots, followed by the third molars and second pre-molars. Although the periapical radiograph is a two-dimensional method, it can provide dentists with the auxiliary information necessary to identify alveolar domes, thus improving diagnosis, planning, and treatment. PMID:27672614

  18. An automatic early stage alveolar-bone-resorption evaluation method on digital dental panoramic radiographs

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Katsumata, Akitoshi; Muramatsu, Chisako; Hara, Takeshi; Suzuki, Hiroki; Fujita, Hiroshi

    2014-03-01

    Periodontal disease is a kind of typical dental diseases, which affects many adults. The presence of alveolar bone resorption, which can be observed from dental panoramic radiographs, is one of the most important signs of the progression of periodontal disease. Automatically evaluating alveolar-bone resorption is of important clinic meaning in dental radiology. The purpose of this study was to propose a novel system for automated alveolar-bone-resorption evaluation from digital dental panoramic radiographs for the first time. The proposed system enables visualization and quantitative evaluation of alveolar bone resorption degree surrounding the teeth. It has the following procedures: (1) pre-processing for a test image; (2) detection of tooth root apices with Gabor filter and curve fitting for the root apex line; (3) detection of features related with alveolar bone by using image phase congruency map and template matching and curving fitting for the alveolar line; (4) detection of occlusion line with selected Gabor filter; (5) finally, evaluation of the quantitative alveolar-bone-resorption degree in the area surrounding teeth by simply computing the average ratio of the height of the alveolar bone and the height of the teeth. The proposed scheme was applied to 30 patient cases of digital panoramic radiographs, with alveolar bone resorption of different stages. Our initial trial on these test cases indicates that the quantitative evaluation results are correlated with the alveolar-boneresorption degree, although the performance still needs further improvement. Therefore it has potential clinical practicability.

  19. Weld defect detection on digital radiographic image using level set method

    NASA Astrophysics Data System (ADS)

    Halim, Suhaila Abd; Petrus, Bertha Trissan; Ibrahim, Arsmah; Manurung, Yupiter HP; Jayes, Mohd Idris

    2013-09-01

    Segmentation is the most critical task and widely used to obtain useful information in image processing. In this study, Level set based on Chan Vese method is explored and applied to define weld defect on digital radiographic image and its accuracy is evaluated to measure its performance. A set of images with region of interest (ROI) that contain defect are used as input image. The ROI image is pre-processed to improve their quality for better detection. Then, the image is segmented using level set method that is implemented using MATLAB R2009a. The accuracy of the method is evaluated using Receiver Operating Characteristic (ROC). Experimental results show that the method generated an area underneath the ROC of 0.7 in the set of images and the operational point reached corresponds to 0.6 of sensitivity and 0.8 of specificity. The application of segmentation technique such as Chan-Vese level set able to assist radiographer in detecting the defect on digital radiographic image accurately.

  20. Elongated styloid process evaluation on digital panoramic radiograph in a North Italian population

    PubMed Central

    Gracco, Antonio; De Stefani, Alberto; Balasso, Paolo; Alessandri-Bonetti, Giulio; Stellini, Edoardo

    2017-01-01

    Background The aim of this study is to evaluate the prevalence of elongated styloid process in digital panoramic radiographs in a North Italian population in relation to age, gender and side. Material and Methods This study was performed as a retrospective analysis on digital panoramic radiographs of 600 (271 males and 329 females) Italian patients between 6 and 87 years old. The styloid process length were measured using the measuring tool of Sidexis Software. It was measured from the point where it left the temporal bone plate to its tip. Styloid processes measuring more than 30 mm were considered elongated. Chi-squared and Fisher tests were used and the test is considered significant if the p-value is lower or equal to 0.05. Results Thirty-three per cent of the patients showed an elongated styloid process. Seventeen per cent were elongated on both right and left side, fifteen point nine per cent were elongated only in one side. Conclusions The prevalence of elongated styloid process was high and a progressive increase of the elongation prevalence was found in older groups. Key words:Elongated styloid process, Eagle’s syndrome, panoramic radiograph. PMID:28298982

  1. An algorithm for kilovoltage x-ray dose calculations with applications in kV-CBCT scans and 2D planar projected radiographs

    NASA Astrophysics Data System (ADS)

    Pawlowski, Jason M.; Ding, George X.

    2014-04-01

    A new model-based dose calculation algorithm is presented for kilovoltage x-rays and is tested for the cases of calculating the radiation dose from kilovoltage cone-beam CT (kV-CBCT) and 2D planar projected radiographs. This algorithm calculates the radiation dose to water-like media as the sum of primary and scattered dose components. The scatter dose is calculated by convolution of a newly introduced, empirically parameterized scatter dose kernel with the primary photon fluence. Several approximations are introduced to increase the scatter dose calculation efficiency: (1) the photon energy spectrum is approximated as monoenergetic; (2) density inhomogeneities are accounted for by implementing a global distance scaling factor in the scatter kernel; (3) kernel tilting is ignored. These approximations allow for efficient calculation of the scatter dose convolution with the fast Fourier transform. Monte Carlo simulations were used to obtain the model parameters. The accuracy of using this model-based algorithm was validated by comparing with the Monte Carlo method for calculating dose distributions for real patients resulting from radiotherapy image guidance procedures including volumetric kV-CBCT scans and 2D planar projected radiographs. For all patients studied, mean dose-to-water errors for kV-CBCT are within 0.3% with a maximum standard deviation error of 4.1%. Using a medium-dependent correction method to account for the effects of photoabsorption in bone on the dose distribution, mean dose-to-medium errors for kV-CBCT are within 3.6% for bone and 2.4% for soft tissues. This algorithm offers acceptable accuracy and has the potential to extend the applicability of model-based dose calculation algorithms from megavoltage to kilovoltage photon beams.

  2. Estimation of percentage breast tissue density: comparison between digital mammography (2D full field digital mammography) and digital breast tomosynthesis according to different BI-RADS categories

    PubMed Central

    Cavagnetto, F; Calabrese, M; Houssami, N

    2013-01-01

    Objective: To compare breast density estimated from two-dimensional full-field digital mammography (2D FFDM) and from digital breast tomosynthesis (DBT) according to different Breast Imaging–Reporting and Data System (BI-RADS) categories, using automated software. Methods: Institutional review board approval and written informed patient consent were obtained. DBT and 2D FFDM were performed in the same patients to allow within-patient comparison. A total of 160 consecutive patients (mean age: 50±14 years; mean body mass index: 22±3) were included to create paired data sets of 40 patients for each BI-RADS category. Automatic software (MedDensity©, developed by Giulio Tagliafico) was used to compare the percentage breast density between DBT and 2D FFDM. The estimated breast percentage density obtained using DBT and 2D FFDM was examined for correlation with the radiologists' visual BI-RADS density classification. Results: The 2D FFDM differed from DBT by 16.0% in BI-RADS Category 1, by 11.9% in Category 2, by 3.5% in Category 3 and by 18.1% in Category 4. These differences were highly significant (p<0.0001). There was a good correlation between the BI-RADS categories and the density evaluated using 2D FFDM and DBT (r=0.56, p<0.01 and r=0.48, p<0.01, respectively). Conclusion: Using DBT, breast density values were lower than those obtained using 2D FFDM, with a non-linear relationship across the BI-RADS categories. These data are relevant for clinical practice and research studies using density in determining the risk. Advances in knowledge: On DBT, breast density values were lower than with 2D FFDM, with a non-linear relationship across the classical BI-RADS categories. PMID:24029631

  3. Single-shot and phase-shifting digital holographic microscopy using a 2-D grating.

    PubMed

    Yang, Taeseok Daniel; Kim, Hyung-Jin; Lee, Kyoung J; Kim, Beop-Min; Choi, Youngwoon

    2016-05-02

    We demonstrate digital holographic microscopy that, while being based on phase-shifting interferometry, is capable of single-shot measurements. A two-dimensional (2-D) diffraction grating placed in a Fourier plane of a standard in-line holographic phase microscope generates multiple copies of a sample image on a camera sensor. The identical image copies are spatially separated with different overall phase shifts according to the diffraction orders. The overall phase shifts are adjusted by controlling the lateral position of the grating. These phase shifts are then set to be multiples of π/2. Interferograms composed of four image copies combined with a parallel reference beam are acquired in a single shot. The interferograms are processed through a phase-shifting algorithm to produce a single complex image. By taking advantage of the higher sampling capacity of the in-line holography, we can increase the imaging information density by a factor of 3 without compromising the imaging acquisition speed.

  4. [Technical parameters to decrease the radiation dose from conventional and digital radiographs].

    PubMed

    Foulquier, J N

    2010-11-01

    Reducing radiation dose while maintaining adequate image quality on conventional and digital radiographs requires optimal use of the unit. Additional filtration avoids unnecessary tissue exposure and improves photon transmission. Automatic exposure control may reduce exposure and dose. The volume of tissue imaged must be limited by the use of diaphragms and shutters or compression. Sensitive detectors with increased photon detection also contribute to reduce dose. Radiographic films combined to rare-earth screens also afford a good photon-conversion efficiency. Large area flat panel amorphous silicon x-ray sensors may also reduce dose up to 50% compared to films. Finally, calculation of the Kerma-area product independent of the source distance constitutes an important indicator of radiation dose.

  5. Evaluation of proximal caries in images resulting from different modes of radiographic digitalization

    PubMed Central

    Xavier, CRG; Araujo-Pires, AC; Poleti, ML; Rubira-Bullen, IRF; Ferreira, O; Capelozza, ALA

    2011-01-01

    Objective The aim of this study was to evaluate the performances of observers in diagnosing proximal caries in digital images obtained from digital bitewing radiographs using two scanners and four digital cameras in Joint Photographic Experts Group (JPEG) and tagged image file format (TIFF) files, and comparing them with the original conventional radiographs. Method In total, 56 extracted teeth were radiographed with Kodak Insight film (Eastman Kodak, Rochester, NY) in a Kaycor Yoshida X-ray device (Kaycor X-707; Yoshida Dental Manufacturing Co., Tokyo, Japan) operating at 70 kV and 7 mA with an exposure time of 0.40 s. The radiographs were obtained and scanned by CanonScan D646U (Canon USA Inc., Newport News, VA) and Genius ColorPage HR7X (KYE Systems Corp. America, Doral, FL) scanners, and by Canon Powershot G2 (Canon USA Inc.), Canon RebelXT (Canon USA Inc.), Nikon Coolpix 8700 (Nikon Inc., Melville, NY), and Nikon D70s (Nikon Inc.) digital cameras in JPEG and TIFF formats. Three observers evaluated the images. The teeth were then observed under the microscope in polarized light for the verification of the presence and depth of the carious lesions. Results The probability of no diagnosis ranged from 1.34% (Insight film) to 52.83% (CanonScan/JPEG). The sensitivity ranged from 0.24 (Canon RebelXT/JPEG) to 0.53 (Insight film), the specificity ranged from 0.93 (Nikon Coolpix/JPEG, Canon Powershot/TIFF, Canon RebelXT/JPEG and TIFF) to 0.97 (CanonScan/TIFF and JPEG) and the accuracy ranged from 0.82 (Canon RebelXT/JPEG) to 0.91 (CanonScan/JPEG). Conclusion The carious lesion diagnosis did not change in either of the file formats (JPEG and TIFF) in which the images were saved for any of the equipment used. Only the CanonScan scanner did not have adequate performance in radiography digitalization for caries diagnosis and it is not recommended for this purpose. PMID:21831972

  6. Sexual dimorphism in foramen magnum dimensions in the South Indian population: A digital submentovertex radiographic study

    PubMed Central

    Raikar, Neha Ajit; Meundi, Manasa A; David, Chaya M; Rao, Mahesh Dathu; Jogigowda, Sanjay Chikkarasinakere

    2016-01-01

    Purpose of the Study: Personal identification is a vital arena of forensic investigation, facilitating the search for missing persons. This process of identification is eased by the determination of age, sex, and ethnicity. In situations where there are fragmented and mutilated skeletal remains, sex determination is relatively difficult, and it becomes important to establish the accuracy of individual bones. Aim: This study aims to evaluate sexual dimorphism in foramen magnum (FM) dimensions in the South Indian population using digital submentovertex (SMV) radiograph. Materials and Methods: 150 individuals (75 males and 75 females) were subjected to digital SMV radiography. FM in the resultant image was assessed for longitudinal and transverse diameters, circumference, and area. Also, one particular shape was assigned to each image based on the classification of Chethan et al. of FM shapes. Three qualified oral radiologists performed all the measurements twice within an interval of 10 days. Results and Conclusion: The values obtained for all four parameters were statistically significant and higher in males than in females. The most common morphology of FM was an egg shape while hexagonal was the least common morphology. Circumference was the best indicator of sex followed by area, transverse diameter, and longitudinal diameter. Having achieved a high accuracy of 67.3% with digital SMV radiograph makes it a reliable and reproducible alternative to dry skulls for sex determination. PMID:28123285

  7. DIGITAL RADIOGRAPHIC EVALUATION OF OPTICAL DENSITY OF PORCELAINS USED FOR FABRICATION OF INLAY/ONLAY PROSTHESIS

    PubMed Central

    CASTILHO, Julio Cezar de Melo; TAKESHITA, Wilton Mitsunari; dos SANTOS, Luis Roque de Araújo; de MORAES, Luiz Cesar; MEDICI, Edmundo; de MORAES, Mari Eli Leonelli

    2006-01-01

    The purpose of this article was to compare the mean value of optical density of four porcelains commonly used for fabrication of inlay/onlay prostheses using direct digital radiograph. The sample consisted of 20 2-mm thick porcelain specimens (measured by digital pachymeter): Empress (Ivoclair), Simbios (Degussa), Vita Omega 900 and Vitadur Alpha (Vita Zahnfabrik). The values of optical density of the specimens were expressed in millimeters aluminum equivalent (mm eq Al). The samples were X-rayed using two charge coupled devices (CCD) - RVG (Trophy) - Visualix (Gendex) and a phosphor plate system – Digora (Soredex). The optical density reading was performed with Image Tool 1.28 in a total of 110 measurements. Statistical analysis showed that there were statistically significant differences in all materials studied (p < 0.05) regardless of the radiographic system used. The highest optical density value was found for Omega 900 (1.8988 mmeqAl – Visualix – Gendex) and the lowest for Vitadur Alpha (0.8647 – Visualix – Gendex). Thus, the material presenting the highest degree of optical density was Omega 900, Empress and Simbios presented intermediate optical density values, Vitadur Alpha presented the lowest value, and the optical density of porcelains was not influenced by the digital radiography systems. PMID:19089024

  8. Accuracy and Reliability of Preoperative On-screen Templating Using Digital Radiographs for Total Hip Arthroplasty

    PubMed Central

    Shin, Jong Ki; Son, Seung Min; Kim, Tae Woo; Shin, Won Chul; Lee, Jung Sub

    2016-01-01

    Purpose Preoperative on-screen templating is a method of using acetate templates on digital images. The aim of the present study was to evaluate the accuracy, intra- and interobserver reliabilities of preoperative on-screen templating using digital radiographs for total hip arthroplasty (THA). Materials and Methods Two hundred patients with hip disease who were treated with primary cementless THA were retrospectively evaluated. The accuracy of on-screen templating was assessed by comparing the predicted prosthesis sizes with the actual sizes used operatively. The inter- and intraobserver reliabilities of the templating results were also evaluated. Results The prosthesis prediction accuracy within ±one size was 96.6% for the cup size and 97.8% for the stem size. The inter- and intraobserver reliabilities for the implant size were substantial (kappa>0.70). The intra- and interobserver reliabilities for the leg length discrepancy and femoral offset difference using the intraclass correlation coefficient ranged from 0.89 to 0.97. Conclusion Preoperative on-screen templating using digital radiographs showed substantial accuracy and reliability for implant prediction. It is an effective method for predicting the size of implant, correcting the leg length discrepancy and restoring the femoral offset. PMID:28097109

  9. Determination of sexual dimorphism in humans by measurements of mandible on digital panoramic radiograph

    PubMed Central

    Sairam, V.; Geethamalika, M. V.; Kumar, Praveen B.; Naresh, G.; Raju, Gareema P.

    2016-01-01

    Background: Identification of sex is the first step in forensic science obtained from skeletal remains. Mandible, being a strong bone that is difficult to damage and disintegrate, is an important tool in sex determination. The present study is aimed to assess, compare, and evaluate the mandibular measurements as seen on digital panoramic radiographs to analyze their use in sexual dimorphism assessment. Materials and Methods: This retrospective study was conducted using digital panoramic images of 100 each in both genders. Mandibular measurements were carried out utilizing RadiAnt DICOM Viewer 2.2.9 (32 bit) software (Medixant Company, Poland) and subjected to statistical analysis. Results: Descriptive statistics for all the parameters on the right and left sides of mandible in both males and females were analyzed. Inferential statistics were performed using t-test to compare males and females with different variables. A statistical significance of P < 0.001 has been demonstrated for all the variables (except linear measurement of mandibular foramen). All variables showed increased measurements in males than in females. The accuracy of sex determination in mandibular ramus measurements is 79.5% on right side and 77% on left side, where as, in linear mandibular measurements it is 76% on right side and 79.5% on left side. Conclusion: Mandibular measurements on digital radiograph are useful in sex determination, and this study can be compared with other similar studies. PMID:27994407

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

    PubMed Central

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

    2016-01-01

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

  11. Optimisation of the digital radiographic imaging of suspected non-accidental injury

    NASA Astrophysics Data System (ADS)

    Offiah, Amaka

    Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI). Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI. Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor. Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection

  12. Perona Malik anisotropic diffusion model using Peaceman Rachford scheme on digital radiographic image

    SciTech Connect

    Halim, Suhaila Abd; Razak, Rohayu Abd; Ibrahim, Arsmah; Manurung, Yupiter HP

    2014-06-19

    In image processing, it is important to remove noise without affecting the image structure as well as preserving all the edges. Perona Malik Anisotropic Diffusion (PMAD) is a PDE-based model which is suitable for image denoising and edge detection problems. In this paper, the Peaceman Rachford scheme is applied on PMAD to remove unwanted noise as the scheme is efficient and unconditionally stable. The capability of the scheme to remove noise is evaluated on several digital radiography weld defect images computed using MATLAB R2009a. Experimental results obtained show that the Peaceman Rachford scheme improves the image quality substantially well based on the Peak Signal to Noise Ratio (PSNR). The Peaceman Rachford scheme used in solving the PMAD model successfully removes unwanted noise in digital radiographic image.

  13. Impact of resolution and noise characteristics of digital radiographic detectors on the detectability of lung nodules.

    PubMed

    Saunders, Robert S; Samei, Ehsan; Hoeschen, Christoph

    2004-06-01

    One of the unanswered questions in digital radiography is the connection between physical image quality metrics and clinical detection performance. In this paper, we examine the impact of two physical metrics, resolution and noise, on the detectability of nodules in a pulmonary background for specific digital radiographic detectors. A detection experiment was performed on a simulated image set using anatomical backgrounds from a high-quality lung radiograph and three different simulated nodule sizes (2-3.5 mm). The resolution and noise of the resulting images were modified using existing routines to simulate a selenium-based and a cesium iodide-based flat-panel detector at comparable exposures. A location-known-exactly (LKE) observer performance experiment was performed in which four experienced chest radiologists and three physicists specializing in chest radiology scored the images. The data from the observer experiment were analyzed by receiver operating characteristic (ROC) methodology. The detectability, as measured by the parameter Az, was higher for the selenium detector than the cesium iodide detector for all nodule sizes by an average of 8.5%. For one nodule size (2.75 mm), the difference between detectors was statistically significant (p < 0.01). The findings indicate that for the particular task studied, the superior resolution performance of the selenium-based detector provided better detectability of subtle lung nodules even though the images had greater noise than images obtained with the cesium iodide detector.

  14. Remapping of digital subtraction angiography on a standard fluoroscopy system using 2D-3D registration

    NASA Astrophysics Data System (ADS)

    Alhrishy, Mazen G.; Varnavas, Andreas; Guyot, Alexis; Carrell, Tom; King, Andrew; Penney, Graeme

    2015-03-01

    Fluoroscopy-guided endovascular interventions are being performing for more and more complex cases with longer screening times. However, X-ray is much better at visualizing interventional devices and dense structures compared to vasculature. To visualise vasculature, angiography screening is essential but requires the use of iodinated contrast medium (ICM) which is nephrotoxic. Acute kidney injury is the main life-threatening complication of ICM. Digital subtraction angiography (DSA) is also often a major contributor to overall patient radiation dose (81% reported). Furthermore, a DSA image is only valid for the current interventional view and not the new view once the C-arm is moved. In this paper, we propose the use of 2D-3D image registration between intraoperative images and the preoperative CT volume to facilitate DSA remapping using a standard fluoroscopy system. This allows repeated ICM-free DSA and has the potential to enable a reduction in ICM usage and radiation dose. Experiments were carried out using 9 clinical datasets. In total, 41 DSA images were remapped. For each dataset, the maximum and averaged remapping accuracy error were calculated and presented. Numerical results showed an overall averaged error of 2.50 mm, with 7 patients scoring averaged errors < 3 mm and 2 patients < 6 mm.

  15. In vivo accuracy of conventional and digital radiographic methods in confirming root canal working length determination by Root ZX

    PubMed Central

    OROSCO, Fernando Accorsi; BERNARDINELI, Norberti; GARCIA, Roberto Brandão; BRAMANTE, Clovis Monteiro; DUARTE, Marco Antonio Húngaro; de MORAES, Ivaldo Gomes

    2012-01-01

    Objectives To compare, in vivo, the accuracy of conventional and digital radiographic methods in determining root canal working length. Material and Methods Twenty-five maxillary incisor or canine teeth from 22 patients were used in this study. Considering the preoperative radiographs as the baseline, a 25 K file was inserted into the root canal to the point where the Root ZX electronic apex locator indicated the APEX measurement in the screen. From this measurement, 1 mm was subtracted for positioning the file. The radiographic measurements were made using a digital sensor (Digora 1.51) or conventional type-E films, size 2, following the paralleling technique, to determine the distance of the file tip and the radiographic apex. Results The Student "t" test indicated mean distances of 1.11 mm to conventional and 1.20 mm for the digital method and indicated a significant statistical difference (p<0.05). Conclusions The conventional radiographic method was found to be superior to the digital one in determining the working length of the root canal. PMID:23138737

  16. Linear densitometry and digital image processing of proximal femur radiographs: implications for archaeological and forensic anthropology.

    PubMed

    Macchiarelli, R; Bondioli, L

    1994-01-01

    Age- and sex-related patterns of proximal femur trabecular bone loss have previously been used to establish radiographic reference standards for estimating age at death for human skeletal remains. Such standards are of interest to both anthropologists and forensic scientists. However, osteopenia as a physiological phenomenon is dependent on numerous genetic, environmental, and cultural factors. Thus, while general age- and sex-related trends can be clearly observed for trabecular bone loss, such patterns also demonstrate marked variation among individuals of both sexes at all ages. Moreover, clinical evidence shows that rates of bone loss are not steady but episodic, and that radiographically "normal" (i.e., young adult) patterns of trabecular bone architecture can also exist in femora of older individuals, particularly within samples of African origin. In this study, adult proximal femur radiographs were used to explore patterns of age- and sex-related proximal femur cancellous bone involution among a sample of 66 African-American individuals from the Terry collection (33 males and 33 females), ranging in age from 19 to 71 years. The proximal femur radiographs of these subjects were analyzed by digital image processing (DIP), and the results were compared to those obtained by laser linear densitometric analyses (LDA) previously performed on the same series (Macchiarelli et al., 1987). Results of LDA and DIP analyses indicate (a) more pronounced bone density decrease in females; (b) sex- and site-specific structural patterns of proximal femur trabecular bone loss; (c) a high level of individual variability, in which predicted age deviated from real age by as much as 22.26 (males) and 30.78 years (females); (d) a moderate linear correlation with age for all the variables analyzed; and (e) an average discrepancy between known age and predicted age (measured by root mean squared residual values) of 10.34 (males) and 12.71 years (females) for the most satisfactory DIP

  17. Investigating digit ratio (2D:4D) in a highly male-dominated occupation: the case of firefighters.

    PubMed

    Voracek, Martin; Pum, Ulrike; Dressler, Stefan G

    2010-04-01

    Second-to-fourth digit ratio (2D:4D), a widely studied putative marker for masculinization through prenatal androgen exposure, is lower (more masculinized) in athletes than in general population controls, and athletes with lower 2D:4D have higher sporting success. Occupations differ markedly in perceived masculinity and actual maleness (sex ratios), but these givens have not yet been picked up and utilized in 2D:4D research. Accordingly, this study extended existing accounts on 2D:4D in athletes to a novel approach: 2D:4D and possible relationships to a variety of candidate variables (demographic, fertility-related, psychological, and other) were investigated in firefighters, a highly male-dominated occupation. Contrary to expectation, 2D:4D in firefighters (N = 134) was not lower than in local male population controls. Lower 2D:4D corresponded to lower service ranks. Replicating previous findings either unequivocally or partly, lower 2D:4D was associated with larger family size, later sibling position, left-handedness, and higher scores in the disinhibition component of sensation seeking. Not replicating prior evidence, 2D:4D was unrelated to body-mass index, offspring sex ratio, and sporting performance level. Novel findings included low 2D:4D in those with low relationship satisfaction and in cigarette smokers, especially among heavy smokers. Absolute finger length, a positive correlate of pubertal-adolescent androgen levels, was also considered. This marker showed negative associations with relationship consensus and satisfaction and positive ones with perceived quality of relationship alternatives and the experience seeking component of sensation seeking. The merits of this additional marker, relative to 2D:4D, for supplementing studies of possible sex-hormonal effects on personality and directions for future inquiry along these lines are discussed.

  18. Damage Assessment and Digital 2D-3D Documentation of PetraTreasury

    NASA Astrophysics Data System (ADS)

    Bala'awi, Fadi; Alshawabkeh, Yahya; Alawneh, Firas; Masri, Eyed al

    The treasury is the icon monument of the world heritage site of ancient Petra city. Unfortunately, this important part of the world's cultural heritage is gradually being diminished due to weathering and erosion problems. This give rise to the need to have a comprehensive study and full documentation of the monument in order to evaluate its status. In this research a comprehensive approach utilizing 2D-3D documentation of the structure using laser scanner and photogrammetry is carried parallel with a laboratory analysis and a correlation study of the salt content and the surface weathering forms. In addition, the research extends to evaluate a set of chemical and physical properties of the case study monument. Studies of stone texture and spatial distribution of soluble salts were carried out at the monument in order to explain the mechanism of the weathering problem. Then a series of field work investigations and laboratory work were undertaken to study the effect of relative humidity, temperature, and wind are the main factors in the salt damage process. The 3D modelling provides accurate geometric and radiometric properties of the damage shape. In order to support the visual quality of 3D surface details and cracks, a hybrid approach combining data from the laser scanner and the digital imagery was developed. Based on the findings, salt damage appears to be one of the main problems at this monument. Although, the total soluble salt content are quite low, but the salts contamination is all over the tested samples in all seasons, with higher concentrations at deep intervals. The thermodynamic calculations carried out by this research have also shown that salt damage could be minimised by controlling the surrounding relative humidity conditions. This measure is undoubtedly the most challenging of all, and its application, if deemed feasible, should be carried out in parallel with other conservation measures.

  19. [Clinical and comparative study of the image quality of 3 digital radiographic systems, E-speed film and digitalized film

    PubMed

    Bóscolo, F N; de Oliveira, A E; de Almeida, S M; Haiter, C F; Haiter Neto, F

    2001-01-01

    The aim of this study was to evaluate, subjectively, the image quality of two CCD digital systems, a digital storage phosphor system, a digitized film and an E-speed film. Five objects were radiographed with 50, 60 and 70 kVp, with exposure times of 0.08, 0.13, 0.2, 0.4 and 0.8 s. In order to maximize the fidelity of the results, the dental X-ray unit employed was submitted to an evaluation so that the relation between exposure time and dose could be established. A good reproducibility was obtained. Six evaluators analyzed 375 images, using a scoring scale which ranged from 0 to 4. The results revealed different responses, indicating that the storage phosphor system had the best performance, in the various exposures employed. However, it was possible to conclude that all systems studied, except for the Sens-A-Ray, can offer images in ideal conditions for the diagnosis, as long as their latitudes are respected.

  20. Removing Distortion of Periapical Radiographs in Dental Digital Radiography Using Embedded Markers in an External frame

    PubMed Central

    Kafieh, Rahele; Shahamoradi, Mahdi; Hekmatian, Ehsan; Foroohandeh, Mehrdad; Emamidoost, Mostafa

    2012-01-01

    To carry out in vivo and in vitro comparative pilot study to evaluate the preciseness of a newly proposed digital dental radiography setup. This setup was based on markers placed on an external frame to eliminate the measurement errors due to incorrect geometry in relative positioning of cone, teeth and the sensor. Five patients with previous panoramic images were selected to undergo the proposed periapical digital imaging for in vivo phase. For in vitro phase, 40 extracted teeth were replanted in dry mandibular sockets and periapical digital images were prepared. The standard reference for real scales of the teeth were obtained through extracted teeth measurements for in vitro application and were calculated through panoramic imaging for in vivo phases. The proposed image processing thechnique was applied on periapical digital images to distinguish the incorrect geometry. The recognized error was inversely applied on the image and the modified images were compared to the correct values. The measurement findings after the distortion removal were compared to our gold standards (results of panoramic imaging or measurements from extracted teeth) and showed the accuracy of 96.45% through in vivo examinations and 96.0% through in vitro tests. The proposed distortion removal method is perfectly able to identify the possible inaccurate geometry during image acquisition and is capable of applying the inverse transform to the distorted radiograph to obtain the correctly modified image. This can be really helpful in applications like root canal therapy, implant surgical procedures and digital subtraction radiography, which are essentially dependent on precise measurements. PMID:23724372

  1. Radiopacity of Methacrylate and Silorane Composite Resins Using a Digital Radiographic System

    PubMed Central

    Firoozmand, Leily Macedo; Cordeiro, Mariana Gonçalves; Da Silva, Marcos André dos Santos

    2016-01-01

    The aim of this study was to evaluate the radiopacity of silorane and methacrylate resin composites, comparing them to the enamel, dentin, and aluminum penetrometer using a digital image. From six resin composites (Filtek™ P90, Filtek Z350, Filtek Z350 XT flow, Tetric Ceram, TPH Spectrum, and SureFil SDR flow) cylindrical disks (5 × 1 mm) were made and radiographed by a digital method, together with a 15-step aluminum step-wedge and a 1 mm slice of human tooth. The degree of radiopacity of each image was quantified using digital image processing. The mean values of the shades of gray of the tested materials were measured and the equivalent width of aluminum was calculated for each resin. The results of our work yielded the following radiopacity values, given here in descending order: Tetric Ceram > TPH > SDR > Z350 > Z350 flow > P90 > enamel > dentin. The radiopacity of the materials was different both for the enamel and for the dentin, except for resin P90, which was no different than enamel. In conclusion, silorane-based resin exhibited a radiopacity higher than dentin and closest to the enamel; a large portion of the methacrylate-based flow and conventional resins demonstrated greater radiopacity in comparison to dentin and enamel. PMID:27722199

  2. A Comparison of Radiographic Film Densitometry Using a New Computerized Tool with a Digital Densitometer

    PubMed Central

    Fakhar, Hoorieh Bashizadeh; Razavi, Elham Sadat Emadian; Soheilifar, Sepideh; Kharazifard, Mohammad Javad

    2016-01-01

    Objectives: The purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge. Materials and Methods: We reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mm×3m×10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer. Results: The new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new method’s sensitivity in determining density changes was 5.26%, 84.1% and 93.02% in steps 2, 7, and 12 respectively. Conclusions: Our new method has an acceptable sensitivity for determining density changes of at least 7 mmEq/Al. PMID:28127317

  3. Semi-automated location identification of catheters in digital chest radiographs

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Cham, Matthew D.; Henschke, Claudia I.; Yankelevitz, David F.

    2007-03-01

    Localization of catheter tips is the most common task in intensive care unit imaging. In this work, catheters appearing in digital chest radiographs acquired by portable chest x-rays were tracked using a semi-automatic method. Due to the fact that catheters are synthetic objects, its profile does not vary drastically over its length. Therefore, we use forward looking registration with normalized cross-correlation in order to take advantage of a priori information of the catheter profile. The registration is accomplished with a two-dimensional template representative of the catheter to be tracked generated using two seed points given by the user. To validate catheter tracking with this method, we look at two metrics: accuracy and precision. The algorithms results are compared to a ground truth established by catheter midlines marked by expert radiologists. Using 12 objects of interest comprised of naso-gastric, endo-tracheal tubes, and chest tubes, and PICC and central venous catheters, we find that our algorithm can fully track 75% of the objects of interest, with a average tracking accuracy and precision of 85.0%, 93.6% respectively using the above metrics. Such a technique would be useful for physicians wishing to verify the positioning of catheter tips using chest radiographs.

  4. Radiation dosage reduction in general dental practice using digital intraoral radiographic systems.

    PubMed

    Hayakawa, Y; Shibuya, H; Ota, Y; Kuroyanagi, K

    1997-02-01

    This report describes the radiation dosage reduction possible in the general dental practice with two CCD (charge-coupled device)-based intraoral radiographic systems: the RVG-S (Trophy Radiologie, Vincennes, France) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). Radiation dosages (air-kerma; Gy) necessary for obtaining clinically acceptable images were measured at the cone tip using an ionization chamber type 660-1 (Nuclear Associates, Victoreen, Inc., Carle Place, New York, USA). When the RVG-S was used with an Oramatic 70 (Trophy Radiologie) X-ray generator, dosages at the cone tip ranged from 322 to 612 microGy. These corresponded to 40-60% of the dosages necessary when using Ektaspeed dental X-ray film (Eastman Kodak, Rochester, New York, USA) with a Heliodent 70 (Siemens, Erlangen, Germany) X-ray generator. At 60 kVp, the Sens-A-Ray reduced the dosage in the order of 30% compared with Ektaspeed dental X-ray film. Reduction in radiation dosage is one of the benefits of digital intraoral radiographic systems in general dental clinics. The RVG-S provides greater dose savings than does the Sens-A-Ray.

  5. Digit ratio (2D:4D), dominance, reproductive success, asymmetry, and sociosexuality in the BBC Internet Study.

    PubMed

    Manning, John T; Fink, Bernhard

    2008-01-01

    Digit ratio (2D:4D) may be a correlate of prenatal sex steroids, and has been linked to traits, which are influenced by fetal testosterone and estrogen. Here we consider such links in a large Internet study of sex differences (the BBC Internet Study) in which finger lengths were self-measured. Consistent with lab-based findings the 2D:4D in this study shows sexual dimorphism, ethnic differences and higher dimorphism of right 2D:4D than left, thereby indicating that 2D:4D does measure real between-participant variation. High error in self-measurement of fingers reduces effect sizes. However, the large sample size gives assurance that significant effects are likely to be real. We controlled for ethnicity and sexual orientation by considering White heterosexuals only (153,429 participants). Sexual dimorphism was confirmed in 2D:4D and for the difference of right-left 2D:4D. After Bonferroni correction we found highly significant relationships with low effect sizes as follows. In males and females there were negative associations between 2D:4D and dominance. In males there were negative associations between 2D:4D and family size and factors associated with reproductive success. For females these associations were positive. For asymmetry we found U-shaped relationships with 2D:4D in both males and females. We found no relationship between 2D:4D and promiscuity (sociosexuality). In total, we considered 48 relationships and found 29 to be significant. We compare our findings with a similar study reported by Putz et al. (2004), which found only 2 out of 57 correlations to be significant and discuss possible reasons for the discrepancies between the studies.

  6. GPU acceleration for digitally reconstructed radiographs using bindless texture objects and CUDA/OpenGL interoperability.

    PubMed

    Abdellah, Marwan; Eldeib, Ayman; Owis, Mohamed I

    2015-01-01

    This paper features an advanced implementation of the X-ray rendering algorithm that harnesses the giant computing power of the current commodity graphics processors to accelerate the generation of high resolution digitally reconstructed radiographs (DRRs). The presented pipeline exploits the latest features of NVIDIA Graphics Processing Unit (GPU) architectures, mainly bindless texture objects and dynamic parallelism. The rendering throughput is substantially improved by exploiting the interoperability mechanisms between CUDA and OpenGL. The benchmarks of our optimized rendering pipeline reflect its capability of generating DRRs with resolutions of 2048(2) and 4096(2) at interactive and semi interactive frame-rates using an NVIDIA GeForce 970 GTX device.

  7. Evaluation of developmental dental anomalies in digital panoramic radiographs in Southeast Iranian Population

    PubMed Central

    Saberi, Eshagh Ali; Ebrahimipour, Sediqe

    2016-01-01

    Objectives: The objective of this study was to evaluate the prevalence of dental developmental anomalies in digital panoramic radiographs of the patients referred to the Zahedan medical imaging center and to evaluate the frequency of anomalies regarding the disorders in shape, position and number in the Southeast of Iran. Materials and Methods: A total of 1172 panoramic radiographs from 581 males and 586 females aged over 16 years were obtained from the files of the Zahedan medical imaging center between the years of 2014 and 2015. The selected radiographs were evaluated in terms of the anomalies such as dilacerations, taurodontism, supernumerary teeth, congenitally missing teeth, fusion, gemination, tooth impaction, tooth transposition, dens invagination, and peg lateral. Then, the anomalies were compared to each other regarding the frequency of the anomaly type (morphological, positional and numerical). Data were evaluated using descriptive statistics such as frequency and percent, and statistical tests such as X2 at 0.05 significant level using the Statistical Package for the Social Sciences version 16.5. Results: The prevalence of dental anomaly was 213 (18.17%), which was higher in females (9.90) than male, (8.28), however, this difference was not statistically significant (P > 0.05). The prevalence of dilacerated teeth was 62 (5.29%), taurodontism 63 (5.38%), supernumerary teeth 6 (0.51%), congenitally missing teeth 13 (1.11%), fusion 1 (0.09%), gemination 1 (0.09%), impaction 40 (3.41%), transposition 2 (0.18%), dens invagination 16 (1.37) and peg lateral was 9 (0.77%). The prevalence of morphological anomaly was 152 (71.36%), malposition 42 (19.72%) and numerous anomaly was 19 (8.92%). Conclusions: Dental anomalies are relatively common; although their occurrence is not symptomatic, they can lead to several clinical problems in patients. Detailed clinical and radiographic assessment and counseling during patient visits is a critical factor in assessing the

  8. Second to fourth digit ratio (2D:4D) and concentrations of circulating sex hormones in adulthood

    PubMed Central

    2011-01-01

    Background The second to fourth digit ratio (2D:4D) is used as a marker of prenatal sex hormone exposure. The objective of this study was to examine whether circulating concentrations of sex hormones and SHBG measured in adulthood was associated with 2D:4D. Methods This analysis was based on a random sample from the Melbourne Collaborative Cohort Study. The sample consisted of of 1036 men and 620 post-menopausal women aged between 39 and 70 at the time of blood draw. Concentrations of circulating sex hormones were measured from plasma collected at baseline (1990-1994), while digit length was measured from hand photocopies taken during a recent follow-up (2003-2009). The outcome measures were circulating concentrations of testosterone, oestradiol, dehydroepiandrosterone sulphate, androstenedione, Sex Hormone Binding Globulin, androstenediol glucoronide for men only and oestrone sulphate for women only. Free testosterone and oestradiol were estimated using standard formulae derived empirically. Predicted geometric mean hormone concentrations (for tertiles of 2D:4D) and conditional correlation coefficients (for continuous 2D:4D) were obtained using mixed effects linear regression models. Results No strong associations were observed between 2D:4D measures and circulating concentrations of hormones for men or women. For males, right 2D:4D was weakly inversely associated with circulating testosterone (predicted geometric mean testosterone was 15.9 and 15.0 nmol/L for the lowest and highest tertiles of male right 2D:4D respectively (P-trend = 0.04). There was a similar weak association between male right 2D:4D and the ratio of testosterone to oestradiol. These associations were not evident in analyses of continuous 2D:4D. Conclusions There were no strong associations between any adult circulating concentration of sex hormone or SHGB and 2D:4D. These results contribute to the growing body of evidence indicating that 2D:4D is unrelated to adult sex hormone concentrations

  9. Building a 2.5D Digital Elevation Model from 2D Imagery

    NASA Technical Reports Server (NTRS)

    Padgett, Curtis W.; Ansar, Adnan I.; Brennan, Shane; Cheng, Yang; Clouse, Daniel S.; Almeida, Eduardo

    2013-01-01

    When projecting imagery into a georeferenced coordinate frame, one needs to have some model of the geographical region that is being projected to. This model can sometimes be a simple geometrical curve, such as an ellipse or even a plane. However, to obtain accurate projections, one needs to have a more sophisticated model that encodes the undulations in the terrain including things like mountains, valleys, and even manmade structures. The product that is often used for this purpose is a Digital Elevation Model (DEM). The technology presented here generates a high-quality DEM from a collection of 2D images taken from multiple viewpoints, plus pose data for each of the images and a camera model for the sensor. The technology assumes that the images are all of the same region of the environment. The pose data for each image is used as an initial estimate of the geometric relationship between the images, but the pose data is often noisy and not of sufficient quality to build a high-quality DEM. Therefore, the source imagery is passed through a feature-tracking algorithm and multi-plane-homography algorithm, which refine the geometric transforms between images. The images and their refined poses are then passed to a stereo algorithm, which generates dense 3D data for each image in the sequence. The 3D data from each image is then placed into a consistent coordinate frame and passed to a routine that divides the coordinate frame into a number of cells. The 3D points that fall into each cell are collected, and basic statistics are applied to determine the elevation of that cell. The result of this step is a DEM that is in an arbitrary coordinate frame. This DEM is then filtered and smoothed in order to remove small artifacts. The final step in the algorithm is to take the initial DEM and rotate and translate it to be in the world coordinate frame [such as UTM (Universal Transverse Mercator), MGRS (Military Grid Reference System), or geodetic] such that it can be saved in

  10. Digit ratio (2D:4D) predicts sporting success among female fencers independent from physical, experience, and personality factors.

    PubMed

    Voracek, M; Reimer, B; Dressler, S G

    2010-12-01

    Research particularly focusing on male athletes and popular sports (running and soccer) suggests associations of lower (masculinized) second-to-fourth digit ratio (2D:4D), a putative marker of prenatal androgen action, with better sports performance. Studies focusing on women, non-mainstream sports, or controlling for covariates relevant for sporting success are still sparse. This study examined associations between 2D:4D and performance of both male and female athletes active in fencing (a non-mainstream sport dominated by male participants), while controlling for covariates. National fencing rankings and 2D:4D of 58 male and 41 female Austrian tournament fencers (mean age 24 years) were correlated. Among female, but not male, fencers, lower 2D:4D was related to better national fencing rankings. 2D:4D still accounted for incremental variance (12%) in fencing success, when the effects of salient performance factors (age, body mass index, years of fencing, training intensity, and the personality variables achievement, control, harm avoidance, and social potency) were controlled for (totaling 35% attributable variance). Athletes active in the most aggressive form (the sabre) had lower 2D:4D than those active in the other forms (épée and foil fencing). Sporting success in adult life might be partly prenatally programmed via long-lasting extragenital effects of testosterone.

  11. Digit ratio (2D:4D) and male facial attractiveness: new data and a meta-analysis.

    PubMed

    Hönekopp, Johannes

    2013-10-01

    Digit ratio (2D:4D) appears to correlate negatively with prenatal testosterone (T) effects in humans. As T probably increases facial masculinity, which in turn might be positively related to male facial attractiveness, a number of studies have looked into the relationship between 2D:4D and male facial attractiveness, showing equivocal results. Here, I present the largest and third largest samples so far, which investigate the relationship between 2D:4D and male facial attractiveness in adolescents (n = 115) and young men (n = 80). I then present random-effects meta-analyses of the available data (seven to eight samples, overall n = 362 to 469). These showed small (r ≈ -.09), statistically non-significant relationships between 2D:4D measures and male facial attractiveness. Thus, 2D:4D studies offer no convincing evidence at present that prenatal T has a positive effect on male facial attractiveness. However, a consideration of confidence intervals shows that, at present, a theoretically meaningful relationship between 2D:4D and male facial attractiveness cannot be ruled out either.

  12. The function-transferring model construction for X-ray digital radiographic system

    NASA Astrophysics Data System (ADS)

    Xiao, Wang; Yan, Han; Guo, Wenming

    2008-02-01

    This paper is aimed at presenting a renovated model-building method of transfer function for industrial X-ray digital radiography based on the amorphous silicon X-ray flat-panel detector. The system, known as point-spreading function (PSF), is composed of three parts: the system geometrical dispersion with a non-spot power source, the scintillating screen dispersion and the aperture sampling of the pixel detector. For the innovation purpose, we have first of all established a mathematical simulation of the PSF and the modulation transfer function (MTF) on the basis of analyzing the intensity distribution of X-ray penetration area in each part and by taking Gaussian functions as a mathematical equation for depicting the transfer behavior of each part of the system. And, then, we have worked out the approximately effective bandwidth of the system from its half-wave width. And, finally, by taking the digital radiography based on the flat-panel detector for sampling, the paper has provided a theoretical foundation for the industrial X-ray radiographic testing and measurement operation. In addition, the author has also estimated the validation of the model through experiments and proved that the method helps to make high resolutions of the diacritical tiniest details in the work-pieces, which has shown and will show its technical rationality, technical appropriateness and practical working value.

  13. A critical review of the research on the extreme male brain theory and digit ratio (2D:4D).

    PubMed

    Teatero, Missy L; Netley, Charles

    2013-11-01

    Boys are more likely than girls to be diagnosed with an autism spectrum disorder (ASD). The extreme male brain (EMB) theory of ASD suggests that fetal testosterone (FT) exposure may underlie sex differences in autistic traits. A link between the organizational effects of FT on the brain and ASD is often drawn based on research using digit ratio (2D:4D), a putative biomarker, without a full survey of the findings. This paper critically and quantitatively reviews the research on the relationship between 2D:4D and ASD as well as autism spectrum, empathizing, and systemizing measures in neurotypical populations. Overall, there is some support for the EMB theory in all four areas, particularly the 2D:4D-ASD relationship. Recommendations for future research are provided.

  14. New requirements for digital radiographic testing of welds according to ISO standards

    SciTech Connect

    Zscherpel, U.; Ewert, U.; Jechow, M.

    2013-01-25

    Users of EN 14784-2 (general principles for computed radiography with phosphor imaging plates) reported about difficulties to achieve testing class B in weld testing with imaging plates. One of the reasons is the insufficient consideration of the inherent detector unsharpness (u{sub i}) in the minimum requirements. Digital detectors have a higher inherent unsharpness compared to film, which can even exceed the geometrical unsharpness (u{sub g}) of the typical contact technique. In EN 444 and ISO 5579 (general principles for film radiography) u{sub i} is neglected for the calculation of the minimum source-to-object distance (SOD), because it is small compared to the geometric unsharpness (u{sub g}). Considering u{sub i} for digital detectors results in a new equation for SOD (see ISO/FDIS 17636-2). Therefore, the increase in total image unsharpness requires the compensation by a larger SOD to reduce u{sub g}. This contribution discusses the need for change of the SOD for different setups (detectors, focal spots, etc.) and explains the difference in image quality, achieved on basis of the extended equation of ISO/FDIS 17636-2. Furthermore, the detection of image quality indicators depends on the achieved Contrast-to-Noise ratio (CNR) and total image unsharpness. Both of them are essential parameters, which influence the contrast sensitivity. Additionally, new compensation principles (e.g. compensation of missing spatial resolution by enhanced contrast sensitivity) allow to widen the application range of digital detectors for radiographic weld testing.

  15. Hard Copy to Digital Transfer: 3D Models that Match 2D Maps

    ERIC Educational Resources Information Center

    Kellie, Andrew C.

    2011-01-01

    This research describes technical drawing techniques applied in a project involving digitizing of existing hard copy subsurface mapping for the preparation of three dimensional graphic and mathematical models. The intent of this research was to identify work flows that would support the project, ensure the accuracy of the digital data obtained,…

  16. Scaling digital radiographs for templating in total hip arthroplasty using conventional acetate templates independent of calibration markers.

    PubMed

    Brew, Christopher J; Simpson, Philip M; Whitehouse, Sarah L; Donnelly, William; Crawford, Ross W; Hubble, Matthew J W

    2012-04-01

    We describe a scaling method for templating digital radiographs using conventional acetate templates independent of template magnification without the need for a calibration marker. The mean magnification factor for the radiology department was determined (119.8%; range, 117%-123.4%). This fixed magnification factor was used to scale the radiographs by the method described. Thirty-two femoral heads on postoperative total hip arthroplasty radiographs were then measured and compared with the actual size. The mean absolute accuracy was within 0.5% of actual head size (range, 0%-3%) with a mean absolute difference of 0.16 mm (range, 0-1 mm; SD, 0.26 mm). Intraclass correlation coefficient showed excellent reliability for both interobserver and intraobserver measurements with intraclass correlation coefficient scores of 0.993 (95% CI, 0.988-0.996) for interobserver measurements and intraobserver measurements ranging between 0.990 and 0.993 (95% CI, 0.980-0.997).

  17. Radiographic Evaluation of the Status of Third Molars in Sriganganagar Population – A Digital Panoramic Study

    PubMed Central

    Goyal, Sharry; Verma, Pradhuman; Raj, Seetharamaiha Sunder

    2016-01-01

    Background Third molar (M3) agenesis and impaction are associated with evolution, changed dietary habits, and human jaw growth. The aim of the study was to radiographically evaluate the prevalence of M3s agenesis, impacted M3s with different impaction patterns, and the approximation of Inferior Dental Canal (IDC) with impacted mandibular M3s roots among the Sriganganagar population. Methods The study included 700 randomly selected subjects from OPD with an age range of 25–45 years. Digital OPGs were taken for all subjects using Kodak 8000C digital OPG machine. The M3 impaction patterns were evaluated using Winter’s classification. Results The prevalence of subjects with at least one M3 agenesis was found to be 34.1% and with 95% confidence interval was 30.6% to 37.6%. The overall M3s agenesis was 16.8% with more prevalence in the males. The patients with agenesis of one M3, two M3s, three M3s, and four M3s were 14.4%, 11.3%, 3.7% and 4.7%, respectively. M3 agenesis was more in the upper jaw and on the left side. The total impacted M3s were 21.11% with more prevalence in mixed diet subjects. Mesioangular was most common impaction pattern, and notching was most prevalent IDC relationship with impacted mandibular M3s roots. Conclusion This study highlighted the evolutionary increasing M3 agenesis and the importance of diagnostic OPG for seeing the status of M3s in jaws. PMID:28090184

  18. The contributions of Hans-Dieter Rösler: pioneer of digit ratio (2D:4D) research.

    PubMed

    Voracek, Martin; Dressler, Stefan G; Loibl, Lisa Mariella

    2008-12-01

    Over the past decade, the second-to-fourth digit ratio (2D:4D), a putative biomarker for the organizational (permanent) effects of prenatal androgens on the human brain, body, and behavior, has received extensive research attention in psychology. This account makes more widely accessible the contributions of the German psychologist, Hans-Dieter Rösler, an early, for a long time unnoticed, predecessor of modern 2D:4D research. In the mid-1950s, Rösler collected a massive sample of hand outline drawings, totalling nearly 7,000 individuals, ranging in age from 1 mo. to 70 yr. With regard to the distal finger-extent pattern, Rösler differentiated radial (longer index than ring finger), ulnar (reversed pattern), and intermediate hand types, which reflect higher (more female-typical), lower (more male-typical), and intermediate 2D:4D, respectively. Here is summarized Rösler's research. In a series of investigations into the hand types, he reported on their anatomical bases, unsuitability for paternity testing, developmental changes, heritability, sex, side, and occupational group differences, and associations with left-handedness, manual dexterity, mental retardation, and clinodactyly. Based on new data from 313 male and 316 female adults, hand type is further shown to be only a weak proxy of actual 2D:4D, leaving 75% of the interindividual variation in 2D:4D unexplained. Notwithstanding these shortcomings of the hand-type method, Rösler's work from the 1950s still has the potential to inform modern 2D:4D research, as it contains a multitude of testable hypotheses not yet picked up by current research.

  19. Revealing Invisible Beauty, Ultra Detailed: The Influence of Low Cost UV Exposure on Natural History Specimens in 2D+ Digitization

    PubMed Central

    Brecko, Jonathan; Mathys, Aurore; Dekoninck, Wouter; De Ceukelaire, Marleen; VandenSpiegel, Didier; Semal, Patrick

    2016-01-01

    Digitization of the natural history specimens usually occurs by taking detailed pictures from different sides or producing 3D models. Additionally this is normally limited to imaging the specimen while exposed by light of the visual spectrum. However many specimens can see in or react to other spectra as well. Fluorescence is a well known reaction to the ultraviolet (UV) spectrum by animals, plants, minerals etc. but rarely taken into account while examining natural history specimens. Our tests show that museum specimens still fluoresce when exposed to UV light of 395 nm and 365 nm, even after many years of preservation. When the UV exposure is used in the digitization of specimens using our low cost focus stacking (2D+) setup, the resulting pictures reveal more detail than the conventional 2D+ images. Differences in fluorescence using 395 nm or 365 nm UV lights were noticed, however there isn’t a preferred wavelength as some specimens react more to the first, while others have better results with the latter exposure. Given the increased detail and the low cost of the system, UV exposure should be considered while digitizing natural history museum collections. PMID:27536993

  20. Revealing Invisible Beauty, Ultra Detailed: The Influence of Low Cost UV Exposure on Natural History Specimens in 2D+ Digitization.

    PubMed

    Brecko, Jonathan; Mathys, Aurore; Dekoninck, Wouter; De Ceukelaire, Marleen; VandenSpiegel, Didier; Semal, Patrick

    2016-01-01

    Digitization of the natural history specimens usually occurs by taking detailed pictures from different sides or producing 3D models. Additionally this is normally limited to imaging the specimen while exposed by light of the visual spectrum. However many specimens can see in or react to other spectra as well. Fluorescence is a well known reaction to the ultraviolet (UV) spectrum by animals, plants, minerals etc. but rarely taken into account while examining natural history specimens. Our tests show that museum specimens still fluoresce when exposed to UV light of 395 nm and 365 nm, even after many years of preservation. When the UV exposure is used in the digitization of specimens using our low cost focus stacking (2D+) setup, the resulting pictures reveal more detail than the conventional 2D+ images. Differences in fluorescence using 395 nm or 365 nm UV lights were noticed, however there isn't a preferred wavelength as some specimens react more to the first, while others have better results with the latter exposure. Given the increased detail and the low cost of the system, UV exposure should be considered while digitizing natural history museum collections.

  1. HipMatch: an object-oriented cross-platform program for accurate determination of cup orientation using 2D-3D registration of single standard X-ray radiograph and a CT volume.

    PubMed

    Zheng, Guoyan; Zhang, Xuan; Steppacher, Simon D; Murphy, Stephen B; Siebenrock, Klaus A; Tannast, Moritz

    2009-09-01

    The widely used procedure of evaluation of cup orientation following total hip arthroplasty using single standard anteroposterior (AP) radiograph is known inaccurate, largely due to the wide variability in individual pelvic orientation relative to X-ray plate. 2D-3D image registration methods have been introduced for an accurate determination of the post-operative cup alignment with respect to an anatomical reference extracted from the CT data. Although encouraging results have been reported, their extensive usage in clinical routine is still limited. This may be explained by their requirement of a CAD model of the prosthesis, which is often difficult to be organized from the manufacturer due to the proprietary issue, and by their requirement of either multiple radiographs or a radiograph-specific calibration, both of which are not available for most retrospective studies. To address these issues, we developed and validated an object-oriented cross-platform program called "HipMatch" where a hybrid 2D-3D registration scheme combining an iterative landmark-to-ray registration with a 2D-3D intensity-based registration was implemented to estimate a rigid transformation between a pre-operative CT volume and the post-operative X-ray radiograph for a precise estimation of cup alignment. No CAD model of the prosthesis is required. Quantitative and qualitative results evaluated on cadaveric and clinical datasets are given, which indicate the robustness and the accuracy of the program. HipMatch is written in object-oriented programming language C++ using cross-platform software Qt (TrollTech, Oslo, Norway), VTK, and Coin3D and is transportable to any platform.

  2. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging.

    PubMed

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies.

  3. A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging

    PubMed Central

    Gallio, Elena; Rampado, Osvaldo; Gianaria, Elena; Bianchi, Silvio Diego; Ropolo, Roberto

    2015-01-01

    Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies. PMID:26545097

  4. A method to produce and validate a digitally reconstructed radiograph-based computer simulation for optimisation of chest radiographs acquired with a computed radiography imaging system

    PubMed Central

    Moore, C S; Liney, G P; Beavis, A W; Saunderson, J R

    2011-01-01

    Objectives The purpose of this study was to develop and validate a computer model to produce realistic simulated computed radiography (CR) chest images using CT data sets of real patients. Methods Anatomical noise, which is the limiting factor in determining pathology in chest radiography, is realistically simulated by the CT data, and frequency-dependent noise has been added post-digitally reconstructed radiograph (DRR) generation to simulate exposure reduction. Realistic scatter and scatter fractions were measured in images of a chest phantom acquired on the CR system simulated by the computer model and added post-DRR calculation. Results The model has been validated with a phantom and patients and shown to provide predictions of signal-to-noise ratios (SNRs), tissue-to-rib ratios (TRRs: a measure of soft tissue pixel value to that of rib) and pixel value histograms that lie within the range of values measured with patients and the phantom. The maximum difference in measured SNR to that calculated was 10%. TRR values differed by a maximum of 1.3%. Conclusion Experienced image evaluators have responded positively to the DRR images, are satisfied they contain adequate anatomical features and have deemed them clinically acceptable. Therefore, the computer model can be used by image evaluators to grade chest images presented at different tube potentials and doses in order to optimise image quality and patient dose for clinical CR chest radiographs without the need for repeat patient exposures. PMID:21933979

  5. Magnification rate of digital panoramic radiographs and its effectiveness for pre-operative assessment of dental implants

    PubMed Central

    Kim, Y-K; Park, J-Y; Kim, S-G; Kim, J-S; Kim, J-D

    2011-01-01

    Objectives The purpose of this study was to determine the accuracy and effectiveness of digital panoramic radiographs for pre-operative assessment of dental implants. Methods We selected 86 patients (221 implants) and calculated the length of the planned implant based on the distance between a selection of critical anatomical structures and the alveolar crest using the scaling tools provided in the digital panoramic system. We analysed the magnification rate and the difference between the actual inserted implant length and planned implant length according to the location of the implant placement and the clarity of anatomical structures seen in the panoramic radiographs. Results There was no significant difference between the planned implant length and actual inserted implant length (P > 0.05). The magnification rate of the width and length of the inserted implants, seen in the digital panoramic radiographs, was 127.28 ± 13.47% and 128.22 ± 4.17%, respectively. The magnification rate of the implant width was largest in the mandibular anterior part and there was a significant difference in the magnification rate of the length of implants between the maxilla and the mandible (P < 0.05). When the clarity of anatomical structures seen in the panoramic radiographs is low, the magnification rate of the width of the inserted implants is significantly higher (P < 0.05), but there is no significant difference between the planned implant length and actual inserted implant length according to the clarity of anatomical structures (P < 0.05). Conclusions Digital panoramic radiography can be considered a simple, readily available and considerably accurate pre-operative assessment tool in the vertical dimension for dental implant therapy. PMID:21239569

  6. Multi-imaging capabilities of a 2D diffraction grating in combination with digital holography.

    PubMed

    Paturzo, Melania; Merola, Francesco; Ferraro, Pietro

    2010-04-01

    In this Letter we report on an alternative approach to get multiple images in microscopy, exploiting the capabilities of both a lithium niobate diffraction grating and digital holographic technique. We demonstrate that multi-imaging can be achieved in a lensless configuration by using a hexagonal diffraction grating but overcoming, thanks to digital holography (DH), the many constrains imposed by the grating parameters in multi-imaging with Talbot effect or Talbot array illuminators. In fact, DH permits the numerical reconstruction of the optical field diffracted by the grating, thus obtaining in-focus multiple images in a plane different from the fractional or entire Talbot ones.

  7. Digital Transfer Growth of Patterned 2D Metal Chalcogenides by Confined Nanoparticle Evaporation

    SciTech Connect

    Mahjouri-Samani, Masoud; Tian, Mengkun; Wang, Kai; Boulesbaa, Abdelaziz; Rouleau, Christopher M.; Puretzky, Alexander A.; McGuire, Michael A.; Srijanto, Bernadeta R.; Xiao, Kai; Eres, Gyula; Duscher, Gerd; Geohegan, David B.

    2014-10-19

    Developing methods for the facile synthesis of two-dimensional (2D) metal chalcogenides and other layered materials is crucial for emerging applications in functional devices. Controlling the stoichiometry, number of the layers, crystallite size, growth location, and areal uniformity is challenging in conventional vapor phase synthesis. Here, we demonstrate a new route to control these parameters in the growth of metal chalcogenide (GaSe) and dichalcogenide (MoSe2) 2D crystals by precisely defining the mass and location of the source materials in a confined transfer growth system. A uniform and precise amount of stoichiometric nanoparticles are first synthesized and deposited onto a substrate by pulsed laser deposition (PLD) at room temperature. This source substrate is then covered with a receiver substrate to form a confined vapor transport growth (VTG) system. By simply heating the source substrate in an inert background gas, a natural temperature gradient is formed that evaporates the confined nanoparticles to grow large, crystalline 2D nanosheets on the cooler receiver substrate, the temperature of which is controlled by the background gas pressure. Large monolayer crystalline domains (~ 100 m lateral sizes) of GaSe and MoSe2 are demonstrated, as well as continuous monolayer films through the deposition of additional precursor materials. This novel PLD-VTG synthesis and processing method offers a unique approach for the controlled growth of large-area, metal chalcogenides with a controlled number of layers in patterned growth locations for optoelectronics and energy related applications.

  8. Digital 2D-photogrammetry and direct anthropometry--a comparing study on test accomplishment and measurement data.

    PubMed

    Franke-Gromberg, Christine; Schüler, Grit; Hermanussen, Michael; Scheffler, Christiane

    2010-01-01

    The aim of this methodological anthropometric study was to compare direct anthropometry and digital two-dimensional photogrammetry in 18 male and 27 female subjects, aged 24 to 65 years, from Potsdam, Germany. In view of the rising interest in reliable biometric kephalofacial data, we focussed on head and face measurements. Out of 34 classic facial anatomical landmarks, 27 landmarks were investigated both by direct anthropometry and 2D-photogrammetry; 7 landmarks could not be localized by 2D-photogrammetry. Twenty-six kephalofacial distances were analysed both by direct anthropometry and digital 2D-photogrammetry. Kephalofacial distances are on average 7.6% shorter when obtained by direct anthropometry. The difference between the two techniques is particularly evident in total head height (vertex-gnathion) due to the fact that vertex is usually covered by hair and escapes from photogrammetry. Also the distances photographic sellion-gnathion (1.3 cm, i. e. 11.6%) and nasal-gnathion (1.2 cm, i. e. 9.4%) differ by more than one centimetre. Differences below 0.5 cm between the two techniques were found when measuring mucosa-lip-height (2.2%), gonia (3.0%), glabella-stomion (3.9%), and nose height (glabella-subnasal) (4.0%). Only the estimates of forehead width were significantly narrower when obtained by 2D-photogrammetry (-1.4 cm, -13.1%). The methodological differences increased with increasing magnitude of the kephalometric distance. Apart from these limitations, both techniques are similarly valid and may replace each other.

  9. Digital Transfer Growth of Patterned 2D Metal Chalcogenides by Confined Nanoparticle Evaporation

    DOE PAGES

    Mahjouri-Samani, Masoud; Tian, Mengkun; Wang, Kai; ...

    2014-10-19

    Developing methods for the facile synthesis of two-dimensional (2D) metal chalcogenides and other layered materials is crucial for emerging applications in functional devices. Controlling the stoichiometry, number of the layers, crystallite size, growth location, and areal uniformity is challenging in conventional vapor phase synthesis. Here, we demonstrate a new route to control these parameters in the growth of metal chalcogenide (GaSe) and dichalcogenide (MoSe2) 2D crystals by precisely defining the mass and location of the source materials in a confined transfer growth system. A uniform and precise amount of stoichiometric nanoparticles are first synthesized and deposited onto a substrate bymore » pulsed laser deposition (PLD) at room temperature. This source substrate is then covered with a receiver substrate to form a confined vapor transport growth (VTG) system. By simply heating the source substrate in an inert background gas, a natural temperature gradient is formed that evaporates the confined nanoparticles to grow large, crystalline 2D nanosheets on the cooler receiver substrate, the temperature of which is controlled by the background gas pressure. Large monolayer crystalline domains (~ 100 m lateral sizes) of GaSe and MoSe2 are demonstrated, as well as continuous monolayer films through the deposition of additional precursor materials. This novel PLD-VTG synthesis and processing method offers a unique approach for the controlled growth of large-area, metal chalcogenides with a controlled number of layers in patterned growth locations for optoelectronics and energy related applications.« less

  10. Multi-view learning based robust collimation detection in digital radiographs

    NASA Astrophysics Data System (ADS)

    Mao, Hongda; Peng, Zhigang; Dennerlein, Frank; Shinagawa, Yoshihisa; Zhan, Yiqiang; Zhou, Xiang Sean

    2014-03-01

    In X-ray examinations, it is essential that radiographers carefully use collimation to the appropriate anatomy of interest to minimize the overall integral dose to the patient. The shadow regions are not diagnostically meaningful and could impair the overall image quality. Thus, it is desirable to detect the collimation and exclude the shadow regions to optimize image display. However, due to the large variability of collimated images, collimation detection remains a challenging task. In this paper, we consider a region of interest (ROI) in an image, such as the collimation, can be described by two distinct views, a cluster of pixels within the ROI and the corners of the ROI. Based on this observation, we propose a robust multi-view learning based strategy for collimation detection in digital radiography. Specifically, one view is from random forests learning based region detector, which provides pixel-wise image classification and each pixel is labeled as either in-collimation or out-of-collimation. The other view is from a discriminative, learning-based landmark detector, which detects the corners and localizes the collimation within the image. Nevertheless, given the huge variability of the collimated images, the detection from either view alone may not be perfect. Therefore, we adopt an adaptive view fusing step to obtain the final detection by combining region and corner detection. We evaluate our algorithm in a database with 665 X-ray images in a wide variety of types and dosages and obtain a high detection accuracy (95%), compared with using region detector alone (87%) and landmark detector alone (83%).

  11. Impact of lens distortions on strain measurements obtained with 2D digital image correlation

    NASA Astrophysics Data System (ADS)

    Lava, P.; Van Paepegem, W.; Coppieters, S.; De Baere, I.; Wang, Y.; Debruyne, D.

    2013-05-01

    The determination of strain fields based on displacements obtained via digital image correlation (DIC) at the micro-strain level (≤1000 μm/m) is still a cumbersome task. In particular when high-strain gradients are involved, e.g. in composite materials with multidirectional fibre reinforcement, uncertainties in the experimental setup and errors in the derivation of the displacement fields can substantially hamper the strain identification process. In this contribution, the aim is to investigate the impact of lens distortions on strain measurements. To this purpose, we first perform pure rigid body motion experiments, revealing the importance of precise correction of lens distortions. Next, a uni-axial tensile test on a textile composite with spatially varying high strain gradients is performed, resulting in very accurately determined strains along the fibers of the material.

  12. Experimental validation of 2D uncertainty quantification for digital image correlation.

    SciTech Connect

    Reu, Phillip L.

    2010-03-01

    Because digital image correlation (DIC) has become such an important and standard tool in the toolbox of experimental mechanicists, a complete uncertainty quantification of the method is needed. It should be remembered that each DIC setup and series of images will have a unique uncertainty based on the calibration quality and the image and speckle quality of the analyzed images. Any pretest work done with a calibrated DIC stereo-rig to quantify the errors using known shapes and translations, while useful, do not necessarily reveal the uncertainty of a later test. This is particularly true with high-speed applications where actual test images are often less than ideal. Work has previously been completed on the mathematical underpinnings of DIC uncertainty quantification and is already published, this paper will present corresponding experimental work used to check the validity of the uncertainty equations.

  13. Variability amongst radiographers in the categorization of clinical acceptability for digital trauma radiography

    NASA Astrophysics Data System (ADS)

    Decoster, Robin; Toomey, Rachel; Smits, Dirk; Mol, Harrie; Verhelle, Filip; Butler, Marie-Louise

    2016-03-01

    Introduction: Radiographers evaluate anatomical structures to judge clinical acceptability of a radiograph. Whether a radiograph is deemed acceptable for diagnosis or not depends on the individual decision of the radiographer. Individual decisions cause variation in the accepted image quality. To minimise these variations definitions of acceptability, such as in RadLex, were developed. On which criteria radiographers attribute a RadLex categories to radiographs is unknown. Insight into these criteria helps to further optimise definitions and reduce variability in acceptance between radiographers. Therefore, this work aims the evaluation of the correlation between the RadLex classification and the evaluation of anatomical structures, using a Visual Grading Analysis (VGA) Methods: Four radiographers evaluated the visibility of five anatomical structures of 25 lateral cervical spine radiographs on a secondary class display with a VGA. They judged clinical acceptability of each radiograph using RadLex. Relations between VGAS and RadLex category were analysed with Kendall's Tau correlation and Nagelkerke pseudo-R². Results: The overall VGA score (VGAS) and the RadLex score correlate (rτ= 0.62, p<0.01, R2=0.72) strongly. The observers' evaluation of contrast between bone, air (trachea) and soft tissue has low value in predicting (rτ=0.55, p<0.01, R2=0.03) the RadLex score. The reproduction of spinous processes (rτ=0.67, p<0.01, R2=0.31) and the evaluation of the exposure (rτ=0.65, p<0.01, R2=0.56) have a strong correlation with high predictive value for the RadLex score. Conclusion: RadLex scores and VGAS correlate positively, strongly and significantly. The predictive value of bony structures may support the use of these in the judgement of clinical acceptability. Considerable inter-observer variations in the VGAS within a certain RadLex category, suggest that observers use of observer specific cut

  14. Physical evaluation of prototype high-performance anti-scatter grids: potential for improved digital radiographic image quality.

    PubMed

    Fetterly, Kenneth A; Schueler, Beth A

    2009-01-21

    Grid evaluation for a screen-film x-ray system has typically included independent measurement of the opposing contrast improvement factor and Bucky factor. Neither of these metrics, however, is appropriate when assessing grid performance in a digital imaging environment. For digital radiographic systems, the benefit of an anti-scatter grid is well characterized by the quantum signal-to-noise ratio improvement factor (K(SNR)) provided by the grid. The purpose of this work was to measure K(SNR) of prototype grids designed for use with digital radiographic systems. The prototype grids had 5 mm tall lead septa, fiber interspace material, line rate N = 25 and 36 cm(-1) and ratio r = 15 and 21, respectively. The primary and scatter transmission properties of the grids were measured, and K(SNR) was evaluated over a phantom thickness range of 10-50 cm. To provide a comparison, the K(SNR) of similarly constructed N44r15 and N80r15 grids is also reported. K(SNR) of the prototype grids ranged from 1.4 for the 10 cm phantom to 2.4 for the 50 cm phantom. For the thickest phantom, the SNR improvement factor of the prototype grids was 18-83% higher than that of the N44r15 and N80r15 grids, respectively.

  15. Digital breast tomosynthesis: application of 2D digital mammography CAD to detection of microcalcification clusters on planar projection image

    NASA Astrophysics Data System (ADS)

    Samala, Ravi K.; Chan, Heang-Ping; Lu, Yao; Hadjiiski, Lubomir; Wei, Jun; Helvie, Mark

    2015-03-01

    Computer-aided detection (CAD) has the potential to aid radiologists in detection of microcalcification clusters (MCs). CAD for digital breast tomosynthesis (DBT) can be developed by using the reconstructed volume, the projection views or other derivatives as input. We have developed a novel method of generating a single planar projection (PPJ) image from a regularized DBT volume to emphasize the high contrast objects such as microcalcifications while removing the anatomical background and noise. In this work, we adapted a CAD system developed for digital mammography (CADDM) to the PPJ image and compared its performance with our CAD system developed for DBT volumes (CADDBT) in the same set of cases. For microcalcification detection in the PPJ image using the CADDM system, the background removal preprocessing step designed for DM was not needed. The other methods and processing steps in the CADDM system were kept without modification while the parameters were optimized with a training set. The linear discriminant analysis classifier using cluster based features was retrained to generate a discriminant score to be used as decision variable. For view-based FROC analysis, at 80% sensitivity, an FP rate of 1.95/volume and 1.54/image were achieved, respectively, for CADDBT and CADDM in an independent test set. At a threshold of 1.2 FPs per image or per DBT volume, the nonparametric analysis of the area under the FROC curve shows that the optimized CADDM for PPJ is significantly better than CADDBT. However, the performance of CADDM drops at higher sensitivity or FP rate, resulting in similar overall performance between the two CAD systems. The higher sensitivity of the CADDM in the low FP rate region and vice versa for the CADDBT indicate that a joint CAD system combining detection in the DBT volume and the PPJ image has the potential to increase the sensitivity and reduce the FP rate.

  16. Digital radiographic measurement of approximal caries progression in fluoridated and non-fluoridated areas of Rio de Janeiro, Brazil.

    PubMed

    Lawrence, H P; Benn, D K; Sheiham, A

    1997-12-01

    The effect of fluoridation on approximal caries progression was investigated using serial digitized bitewing images and conventional film images of 290 12-16-year-old schoolchildren who were lifetime residents of either Rio de Janeiro (a fluoridated area) or Mangaratiba and Angra dos Reis (non-fluoridated areas) in the state of Rio de Janeiro, Brazil. One examiner scored a maximum of 28 approximal surfaces of posterior teeth per subject using both methods. The intraexaminer reliability for rating lesion depth with digital images was comparable with that of the conventional bitewing films (namely, intraclass correlation of 0.99 and weighted Kappa scores of 0.82, respectively). Approximal surface D1S was 3.17 +/- 0.25 (sx) in fluoridated areas and 6.64 +/- 0.44 in non-fluoridated areas. After 1 year, the rate of caries progression in approximal surfaces was significantly lower in the fluoridated areas (0.54 +/- 0.14) as compared with the non-fluoridated areas (1.41 +/- 0.20) using Pitts' scoring system for conventional bitewing radiographs (P < 0.001). Similarly, the digital radiographic method was able to detect subtle differences in approximal caries progression in the enamel and the dentin (overall mean: 0.34 mm/year in fluoridated areas vs 0.49 mm/year in non-fluoridated areas, P < 0.05). The two radiographic methods were strongly correlated (rs = 0.7). Assuming a constant rate over time, these results indicate that lesion progression from the outer half of the enamel into the outer half of the dentin takes approximately 3-4 years in schoolchildren from the fluoridated areas compared to 2 1/2 years in the non-fluoridated areas.

  17. Benchmarking the performance of fixed-image receptor digital radiographic systems part 1: a novel method for image quality analysis.

    PubMed

    Lee, Kam L; Ireland, Timothy A; Bernardo, Michael

    2016-06-01

    This is the first part of a two-part study in benchmarking the performance of fixed digital radiographic general X-ray systems. This paper concentrates on reporting findings related to quantitative analysis techniques used to establish comparative image quality metrics. A systematic technical comparison of the evaluated systems is presented in part two of this study. A novel quantitative image quality analysis method is presented with technical considerations addressed for peer review. The novel method was applied to seven general radiographic systems with four different makes of radiographic image receptor (12 image receptors in total). For the System Modulation Transfer Function (sMTF), the use of grid was found to reduce veiling glare and decrease roll-off. The major contributor in sMTF degradation was found to be focal spot blurring. For the System Normalised Noise Power Spectrum (sNNPS), it was found that all systems examined had similar sNNPS responses. A mathematical model is presented to explain how the use of stationary grid may cause a difference between horizontal and vertical sNNPS responses.

  18. Assessment of the 3-d reconstruction and high-resolution geometrical modeling of the human skeletal trunk from 2-D radiographic images.

    PubMed

    Delorme, S; Petit, Y; de Guise, J A; Labelle, H; Aubin, C E; Dansereau, J

    2003-08-01

    This paper presents an in vivo validation of a method for the three-dimensional (3-D) high-resolution modeling of the human spine, rib cage, and pelvis for the study of spinal deformities. The method uses an adaptation of a standard close-range photogrammetry method called direct linear transformation to reconstruct the 3-D coordinates of anatomical landmarks from three radiographic images of the subject's trunk. It then deforms in 3-D 1-mm-resolution anatomical primitives (reference bones) obtained by serial computed tomography-scan reconstruction of a dry specimen. The free-form deformation is calculated using dual kriging equations. In vivo validation of this method on 40 scoliotic vertebrae gives an overall accuracy of 3.3 +/- 3.8 mm, making it an adequate tool for clinical studies and mechanical analysis purposes.

  19. Multichannel response analysis on 2D projection views for detection of clustered microcalcifications in digital breast tomosynthesis

    SciTech Connect

    Wei, Jun Chan, Heang-Ping; Hadjiiski, Lubomir M.; Helvie, Mark A.; Lu, Yao; Zhou, Chuan; Samala, Ravi

    2014-04-15

    Purpose: To investigate the feasibility of a new two-dimensional (2D) multichannel response (MCR) analysis approach for the detection of clustered microcalcifications (MCs) in digital breast tomosynthesis (DBT). Methods: With IRB approval and informed consent, a data set of two-view DBTs from 42 breasts containing biopsy-proven MC clusters was collected in this study. The authors developed a 2D approach for MC detection using projection view (PV) images rather than the reconstructed three-dimensional (3D) DBT volume. Signal-to-noise ratio (SNR) enhancement processing was first applied to each PV to enhance the potential MCs. The locations of MC candidates were then identified with iterative thresholding. The individual MCs were decomposed with Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) basis functions and the channelized Hotelling model was trained to produce the MCRs for each MC on the 2D images. The MCRs from the PVs were fused in 3D by a coincidence counting method that backprojects the MC candidates on the PVs and traces the coincidence of their ray paths in 3D. The 3D MCR was used to differentiate the true MCs from false positives (FPs). Finally a dynamic clustering method was used to identify the potential MC clusters in the DBT volume based on the fact that true MCs of clinical significance appear in clusters. Using two-fold cross validation, the performance of the 3D MCR for classification of true and false MCs was estimated by the area under the receiver operating characteristic (ROC) curve and the overall performance of the MCR approach for detection of clustered MCs was assessed by free response receiver operating characteristic (FROC) analysis. Results: When the HG basis function was used for MCR analysis, the detection of MC cluster achieved case-based test sensitivities of 80% and 90% at the average FP rates of 0.65 and 1.55 FPs per DBT volume, respectively. With LG basis function, the average FP rates were 0.62 and 1.57 per DBT volume at

  20. Evolution of sexual dimorphism in the digit ratio 2D:4D--relationships with body size and microhabitat use in iguanian lizards.

    PubMed

    Gomes, Camilla M; Kohlsdorf, Tiana

    2011-01-01

    The ratio between lengths of digit II and IV (digit ratio 2D:4D) is a morphological feature that likely affects tetrapod locomotor performances in different microhabitats. Modifications of this trait may be triggered by changes in steroids concentrations during embryo development, which might reflect direct selection acting on digit ratio or be solely a consequence of hormonal differences related for example to body size. Here we apply both conventional and phylogenetic analyses on morphological data from 25 lizard species of 3 families of Iguania (Iguanidae, Polychrotidae, and Tropiduridae), in order to verify whether selective pressures related to locomotion in different microhabitats could override the prenatal developmental cues imposed on the digit ratio 2D:4D by differences in body size between males and females. Data suggest that this trait evolved in association with ecological divergence in the species studied, despite the clear effect of body size on the digit ratio 2D:4D. The ecological associations of size-corrected digit ratios were restricted to one sex, and females of species that often use perches exhibited small digit ratios in the front limbs, which translated into larger sexual dimorphism indexes of arboreal species. The results, together with the subsequent discussion, provide outlines for further investigation about possible developmental mechanisms related to the evolution of adaptive changes in digit lengths that may have occurred during the evolution of ecological divergence in squamates.

  1. Evolution of Sexual Dimorphism in the Digit Ratio 2D:4D - Relationships with Body Size and Microhabitat Use in Iguanian Lizards

    PubMed Central

    Gomes, Camilla M.; Kohlsdorf, Tiana

    2011-01-01

    The ratio between lengths of digit II and IV (digit ratio 2D:4D) is a morphological feature that likely affects tetrapod locomotor performances in different microhabitats. Modifications of this trait may be triggered by changes in steroids concentrations during embryo development, which might reflect direct selection acting on digit ratio or be solely a consequence of hormonal differences related for example to body size. Here we apply both conventional and phylogenetic analyses on morphological data from 25 lizard species of 3 families of Iguania (Iguanidae, Polychrotidae, and Tropiduridae), in order to verify whether selective pressures related to locomotion in different microhabitats could override the prenatal developmental cues imposed on the digit ratio 2D:4D by differences in body size between males and females. Data suggest that this trait evolved in association with ecological divergence in the species studied, despite the clear effect of body size on the digit ratio 2D:4D. The ecological associations of size-corrected digit ratios were restricted to one sex, and females of species that often use perches exhibited small digit ratios in the front limbs, which translated into larger sexual dimorphism indexes of arboreal species. The results, together with the subsequent discussion, provide outlines for further investigation about possible developmental mechanisms related to the evolution of adaptive changes in digit lengths that may have occurred during the evolution of ecological divergence in squamates. PMID:22162772

  2. Digit ratio (2D:4D), sex differences, allometry, and finger length of 12-30-year olds: evidence from the British Broadcasting Corporation (BBC) Internet study.

    PubMed

    Manning, John T

    2010-01-01

    Many studies have reported digit ratio (2D:4D) to be sexually dimorphic, (males lower 2D:4D than females). However, Kratochvíl and Flegr ([2009]: Biol Lett 5:643-646) have suggested that 2D regressed on 4D has an allometric regression line with nonzero Y-intercept that is shared by males and females. Thus, 2D is shorter than expected when 4D is long, and males have lower 2D:4D than females because they have longer fingers. In this study, it is shown that this suggestion may be incorrect because sex differences in slope were not considered. Participants were recruited in an Internet study and had an age range of 12-30 years. The expected sex difference in 2D:4D was found, and the regression of 2D on 4D showed a significant sex difference in slope (males lower than females). A comparison of 10 age groups (12 years, 13 years..., 21-30 years) showed that sexual dimorphism for fingers was age dependent, varying from monomorphic to very dimorphic. Changes in sexual dimorphism of 2D:4D were much less marked, but there was a significant reduction in mean 2D:4D with age. The tendency for slopes of 2D regressed on 4D to be lower in males compared with females was significant in eight age groups. Sex difference in 2D:4D varied across the age groups and was positively related to the magnitude of the difference in female and male slopes. In contrast to the report of Kratochvíl and Flegr, it was found that the regression of 2D on 4D showed sex differences in slope, and such differences gave rise to the sexual dimorphism in 2D:4D.

  3. Reliability of Assessing Hand Osteoarthritis on Digital Photographs and Associations With Radiographic and Clinical Findings

    PubMed Central

    Marshall, Michelle; Jonsson, Helgi; Helgadottir, Gudrun P; Nicholls, Elaine; van der Windt, Danielle; Myers, Helen; Dziedzic, Krysia

    2014-01-01

    Objective To investigate the reliability and construct validity of an atlas for grading hand osteoarthritis (OA) on photographs in a separate younger community-dwelling population than the development cohort. Methods Participants were community-dwelling adults (ages ≥50 years) in North Staffordshire, UK with hand pain or hand problems in the last year who attended a research clinic. High-quality photographs were taken in a standardized position. A photographic atlas was used to score hand joints (second and third distal interphalangeal [DIP], second and third proximal interphalangeal [PIP], and first carpometacarpal [CMC] joints) and joint groups (DIP, PIP, and CMC joints) for OA on a 0–3 scale. Hand radiographs were graded for OA using the Kellgren/Lawrence (K/L) grading system. Clinical features (nodes, bony enlargement, and deformity) were determined by physical examination. Associations of photographic hand OA grades with radiographic OA and clinical features were determined to assess construct validity. Results In total, 558 participants (mean age 64 years, 62% women) were included in the analyses. Reliability for scoring OA on the photographs was good (mean intrarater intraclass correlation coefficient [ICC] 0.77 and mean interrater ICC 0.71). At the joint level, photographic hand OA grade was positively associated with radiographic OA grade (Spearman's ρ = 0.19–0.57, P < 0.001) and the number of clinical features (Spearman's ρ = 0.36–0.59, P < 0.001). At the person level, individuals with higher global photographic OA scores had higher summed K/L scores and higher percentages meeting the American College of Rheumatology clinical hand OA criteria. Conclusion This photographic scoring system was reliable and a good indicator of hand OA in a separate younger community-dwelling population than the development cohort. This method of data collection offers researchers a feasible alternative to physical examination and radiography. PMID:26259552

  4. Are digital images good enough? A comparative study of conventional film-screen vs digital radiographs on printed images of total hip replacement.

    PubMed

    Eklund, K; Jonsson, K; Lindblom, G; Lundin, B; Sanfridsson, J; Sloth, M; Sivberg, B

    2004-05-01

    The aim of this study was to evaluate the inter- and intra-observer variability and to find differences in diagnostic safety between digital and analog technique in diagnostic zones around hip prostheses. In 80 patients who had had a total hip replacement (THR) for more than 2 years, a conventional image and a digital image were taken. Gruen's model of seven distinct regions of interest was used for evaluations. Five experienced radiologists observed the seven regions and noted in a protocol the following distances: stem-cement; cement-bone; and stem-bone. All images were printed on hard copies and were read twice. Weighted kappa, kappa(w), analyses were used. The two most frequently loosening regions, stem-cement region 1 and cement-bone region 7, were closely analyzed. In region 1 the five observers had an agreement of 86.75-97.92% between analog and digital images in stem-cement, which is a varied kappa(w) 0.29-0.71. For cement-bone region 7 an agreement of 87.21-90.45% was found, which is a varied kappa(w) of 0.48-0.58. All the kappa values differ significantly from nil. The result shows that digital technique is as good as analog radiographs for diagnosing possible loosening of hip prostheses.

  5. Comparison of 2D Radiographic Images and 3D Cone Beam Computed Tomography for Positioning Head-and-Neck Radiotherapy Patients

    SciTech Connect

    Li Heng; Zhu, X. Ronald Zhang Lifei; Dong Lei; Tung, Sam; Ahamad, Anesa M.D.; Chao, K. S. Clifford; Morrison, William H.; Rosenthal, David I.; Schwartz, David L.; Mohan, Radhe; Garden, Adam S.

    2008-07-01

    Purpose: To assess the positioning accuracy using two-dimensional kilovoltage (2DkV) imaging and three-dimensional cone beam CT (CBCT) in patients with head and neck (H and N) cancer receiving radiation therapy. To assess the benefit of patient-specific headrest. Materials and Methods: All 21 patients studied were immobilized using thermoplastic masks with either a patient-specific vacuum bag (11 of 21, IMA) or standard clear plastic (10 of 21, IMB) headrests. Each patient was imaged with a pair of orthogonal 2DkV images in treatment position using onboard imaging before the CBCT procedure. The 2DkV and CBCT images were acquired weekly during the same session. The 2DkV images were reviewed by oncologists and also analyzed by a software tool based on mutual information (MI). Results: Ninety-eight pairs of assessable 2DkV-CBCT alignment sets were obtained. Systematic and random errors were <1.6 mm for both 2DkV and CBCT alignments. When we compared shifts determined by CBCT and 2DkV for the same patient setup, statistically significant correlations were observed in all three major directions. Among all CBCT couch shifts, 4.1% {>=} 0.5 cm and 18.7% {>=} 0.3 cm, whereas among all 2DkV (MI) shifts, 1.7% {>=} 0.5 cm and 11.2% {>=} 0.3 cm. Statistically significant difference was found on anteroposterior direction between IMA and IMB with the CBCT alignment only. Conclusions: The differences between 2D and 3D alignments were mainly caused by the relative flexibility of certain H and N structures and possibly by rotation. Better immobilization of the flexible neck is required to further reduce the setup errors for H and N patients receiving radiotherapy.

  6. Digit ratio (2D:4D) in Lithuania once and now: testing for sex differences, relations with eye and hair color, and a possible secular change.

    PubMed

    Voracek, Martin; Bagdonas, Albinas; Dressler, Stefan G

    2007-09-01

    The second-to-fourth digit ratio (2D:4D) is a sexually dimorphic somatic trait and has been proposed as a biomarker for the organizational, i.e., permanent, effects of prenatal testosterone on the human brain. Accordingly, recent research has related 2D:4D to a variety of sex-dependent, hormonally influenced traits and phenotypes. The geographical variation in typical 2D:4D is marked and presently poorly understood. This study presents the first investigation into the 2D:4D ratio in a Baltic country. A contemporary sample of 109 Lithuanian men and women was compared with data from a historical sample of 100 Lithuanian men and women, collected and published in the 1880s and rediscovered only now. The findings included the following lines of evidence: (i) seen in an international perspective, the average 2D:4D in Lithuania is low; (ii) there was a sex difference in 2D:4D in the expected direction in both samples; (iii) a previously adduced hypothesis of an association of lighter eye and hair color with higher, i.e., more feminized, 2D:4D received no support in both samples; and (iv) the average 2D:4D in the contemporary sample was higher than in the historical sample. In view of a hypothesized increase in 2D:4D in modern populations, owing to increased environmental levels of endocrine disruptors such as xenoestrogens, this latter finding appears to be of particular notice. However, because finger-length measurement methods differed across the samples, it cannot be safely ruled out that the apparent time trend in Lithuanian 2D:4D in truth is an artifact. The puzzling geographical pattern seen in the 2D:4D ratio and the question of possible time trends therein deserve further investigations.

  7. Applying a 2D based CAD scheme for detecting micro-calcification clusters using digital breast tomosynthesis images: an assessment

    NASA Astrophysics Data System (ADS)

    Park, Sang Cheol; Zheng, Bin; Wang, Xiao-Hui; Gur, David

    2008-03-01

    Digital breast tomosynthesis (DBT) has emerged as a promising imaging modality for screening mammography. However, visually detecting micro-calcification clusters depicted on DBT images is a difficult task. Computer-aided detection (CAD) schemes for detecting micro-calcification clusters depicted on mammograms can achieve high performance and the use of CAD results can assist radiologists in detecting subtle micro-calcification clusters. In this study, we compared the performance of an available 2D based CAD scheme with one that includes a new grouping and scoring method when applied to both projection and reconstructed DBT images. We selected a dataset involving 96 DBT examinations acquired on 45 women. Each DBT image set included 11 low dose projection images and a varying number of reconstructed image slices ranging from 18 to 87. In this dataset 20 true-positive micro-calcification clusters were visually detected on the projection images and 40 were visually detected on the reconstructed images, respectively. We first applied the CAD scheme that was previously developed in our laboratory to the DBT dataset. We then tested a new grouping method that defines an independent cluster by grouping the same cluster detected on different projection or reconstructed images. We then compared four scoring methods to assess the CAD performance. The maximum sensitivity level observed for the different grouping and scoring methods were 70% and 88% for the projection and reconstructed images with a maximum false-positive rate of 4.0 and 15.9 per examination, respectively. This preliminary study demonstrates that (1) among the maximum, the minimum or the average CAD generated scores, using the maximum score of the grouped cluster regions achieved the highest performance level, (2) the histogram based scoring method is reasonably effective in reducing false-positive detections on the projection images but the overall CAD sensitivity is lower due to lower signal-to-noise ratio

  8. 42 CFR 37.44 - Approval of radiographic facilities that use digital radiography systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Communications in Medicine (DICOM) standard PS 3.12-2011 (incorporated by reference, see § 37.10). Applicants... (compact or digital video disc) and formatted to meet specifications of the current DICOM Standard PS...

  9. 42 CFR 37.44 - Approval of radiographic facilities that use digital radiography systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Communications in Medicine (DICOM) standard PS 3.12-2011 (incorporated by reference, see § 37.10). Applicants... (compact or digital video disc) and formatted to meet specifications of the current DICOM Standard PS...

  10. 42 CFR 37.44 - Approval of radiographic facilities that use digital radiography systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Medicine (DICOM) standard PS 3.12-2011 (incorporated by reference, see § 37.10). Applicants will be advised... digital video disc) and formatted to meet specifications of the current DICOM Standard PS...

  11. The second to fourth digit ratio (2D:4D) in a Japanese twin sample: heritability, prenatal hormone transfer, and association with sexual orientation.

    PubMed

    Hiraishi, Kai; Sasaki, Shoko; Shikishima, Chizuru; Ando, Juko

    2012-06-01

    The second to fourth digit ratio has been argued to reflect prenatal hormonal influences and is reportedly associated with various psychological and behavioral traits, such as sexual orientation, cognitive abilities, and personality. We examined genetic and environmental influences on the second to fourth digit ratio (2D:4D) using a Japanese twin sample (N=300). The genetic analysis showed substantial additive genetic influences for both right and left hand 2D:4D. The rest of the variance was explained mainly by environmental influences not shared within twin pairs. These findings were, in general, in accordance with preceding studies with primarily Caucasian twin samples. The bivariate genetic analysis revealed that the additive genetic influences were largely shared between the right and left hand, while the non-shared environmental influences were largely unique to each hand. Results from a comparison of opposite-sex and same-sex twins were not significant, although they were in the predicted direction according to the prenatal hormone transfer hypothesis. Female monozygotic twin pairs discordant in sexual orientation showed significant within-pair differences in left hand 2D:4D, where non-heterosexual twins had lower (more masculinized) 2D:4D. In addition, we found that non-heterosexual male MZ twins had larger (more feminized) 2D:4D than their heterosexual co-twins. These results suggest the existence of non-shared environmental influences that affect both 2D:4D and sexual orientation.

  12. Digitized crime scene forensics: automated trace separation of toolmarks on high-resolution 2D/3D CLSM surface data

    NASA Astrophysics Data System (ADS)

    Clausing, Eric; Vielhauer, Claus

    2015-03-01

    Locksmith forensics is an important and very challenging part of classic crime scene forensics. In prior work, we propose a partial transfer to the digital domain, to effectively support forensic experts and present approaches for a full process chain consisting of five steps: Trace positioning, 2D/3D acquisition with a confocal 3D laser scanning microscope, detection by segmentation, trace type determination, and determination of the opening method. In particular the step of trace segmentation on high-resolution 3D surfaces thereby turned out to be the part most difficult to implement. The reason for that is the highly structured and complex surfaces to be analyzed. These surfaces are cluttered with a high number of toolmarks, which overlap and distort each other. In Clausing et al., we present an improved approach for a reliable segmentation of relevant trace regions but without the possibility of separating single traces out of segmented trace regions. However, in our past research, especially features based on shape and dimension turned out to be highly relevant for a fully automated analysis and interpretation. In this paper, we consequently propose an approach for this separation. To achieve this goal, we use our segmentation approach and expand it with a combination of the watershed algorithm with a graph-based analysis. Found sub-regions are compared based on their surface character and are connected or divided depending on their similarity. We evaluate our approach with a test set of about 1,300 single traces on the exemplary locking cylinder component 'key pin' and thereby are able of showing the high suitability of our approach.

  13. Maternal corticosterone but not testosterone level is associated with the ratio of second-to-fourth digit length (2D:4D) in field vole offspring (Microtus agrestis).

    PubMed

    Lilley, Thomas; Laaksonen, Toni; Huitu, Otso; Helle, Samuli

    2010-03-30

    The steroid environment encountered by a foetus can strongly affect its post-natal physiology and behaviour. It has been proposed that steroid concentrations experienced in utero could be estimated from adults by measuring their second-to-fourth digit length ratio (2D:4D). However, there is still little direct evidence that intra-uterine steroid levels affect individual 2D:4D. We examined whether maternal pre-pregnancy testosterone and corticosterone levels (as estimates of intra-uterine testosterone and corticosterone exposure) affected the 2D:4D of pups in non-domesticated field voles (Microtus agrestis), measured by X-rays at the age of weaning (21 days). Furthermore, for the first time in a non-human species, we studied whether testosterone and corticosterone levels correlated with 2D:4D in adult females. We found that the maternal pre-pregnancy level of testosterone was not associated with offspring 2D:4D in either the left or the right paw. Instead, maternal pre-pregnancy corticosterone level was positively correlated with offspring 2D:4D in the right paw, but unrelated to 2D:4D in the left paw. In addition, the 2D:4D of adult females was not associated with either their circulating testosterone or corticosterone levels. Our results suggest that in field voles maternally administered testosterone is not a major determinant of offspring 2D:4D, whereas maternal stress appears to account for some of the variation in the 2D:4D of their offspring.

  14. Computer-aided diagnosis for detection of cardiomegaly in digital chest radiographs

    NASA Astrophysics Data System (ADS)

    Ishida, Takayuki; Katsuragawa, Shigehiko; Chida, Koichi; MacMahon, Heber; Doi, Kunio

    2005-04-01

    The cardio-thoracic ratio (CTR) is commonly measured manually for the evaluation of cardiomegaly. To determine the CTR automatically, we have developed a computerized scheme based on gray-level histogram analysis and an edge detection technique with feature analysis. The database used in this study consisted of 392 chest radiographs, which included 304 normals and 88 abnormals with cardiomegaly. The pixel size and the quantization level of the image were 0.175 mm and 1024, respectively. We performed a nonlinear density correction to maintain consistency in the density and contrast of the image. Initial heart edge detection was performed by selection of a certain range of pixel values in the histogram of a rectangular area at the center of a low-resolution image. Feature analysis with use of an edge gradient and with the orientation obtained by a Sobel operator was applied for accurate identification of the heart edges, which tend to have large edge gradients in a certain range of orientations. In addition, to determine the CTR, we detected the ribcage edges automatically by using image profile analysis. In 94.9% of all of the cases, the heart edges were detected accurately by use of this scheme. The area under the ROC curve (Az value) in distinguishing between normals and abnormals with cardiomegaly based on the CTR was 0.912. Because the CTR is measured automatically and quickly (in less than 1 sec.), radiologists could save reading time. The computerized scheme will be useful for the assessment of cardiomegaly on chest radiographs.

  15. Your fate is in your hands? Handedness, digit ratio (2D:4D), and selection to a national talent development system.

    PubMed

    Baker, Joseph; Kungl, Ann-Marie; Pabst, Jan; Strauß, Bernd; Büsch, Dirk; Schorer, Jörg

    2013-01-01

    Over the past decade a small evidence base has highlighted the potential importance of seemingly innocuous variables related to one's hands, such as hand dominance and the relative length of the second and fourth digits (2D:4D ratio), to success in sport. This study compared 2D:4D digit ratio and handedness among handball players selected to advance in a national talent development system with those not selected. Participants included 480 youth handball players (240 females and 240 males) being considered as part of the talent selection programme for the German Youth National team. Hand dominance and digit ratio were compared to age-matched control data using standard t-tests. There was a greater proportion of left-handers compared to the normal population in males but not in females. There was also a lower digit ratio in both females and males. However, there were no differences between those selected for the next stage of talent development and those not selected on either handedness or digit ratio. These results add support for general effects for both digit ratio and handedness in elite handball; however, these factors seem inadequate to explain talent selection decisions at this level.

  16. 42 CFR 37.42 - Chest radiograph specifications-digital radiography systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... must conform to the following components of the Digital Imaging and Communications in Medicine (DICOM) standard (incorporated by reference, see § 37.10): (A) DICOM Standard PS 3.3-2011, Annex A—Composite... Grayscale Softcopy Presentation State Information Object Definition. (B) DICOM Standard PS3.4-2011, Annex...

  17. 42 CFR 37.42 - Chest radiograph specifications-digital radiography systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Digital Imaging and Communications in Medicine (DICOM) standard (incorporated by reference, see § 37.10): (A) DICOM Standard PS 3.3-2011, Annex A—Composite Information Object Definitions, sections: Computed... Object Definition. (B) DICOM Standard PS3.4-2011, Annex B—Storage Service Class; Annex...

  18. Digit ratio (2D:4D) in twins: heritability estimates and evidence for a masculinized trait expression in women from opposite-sex pairs.

    PubMed

    Voracek, Martin; Dressler, Stefan G

    2007-02-01

    The second-to-fourth digit ratio (2D:4D) is sexually dimorphic in humans, such that men on average have a lower 2D:4D than women. This somatic trait has been proposed as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behavior. Over the past few years, an accumulating research program has shown 2D:4D to be related to a multitude of sex-dependent, hormonally influenced psychological and behavioral traits. The present study investigated the 2D:4D ratio of 44 men and 70 women from 36 identical and 21 fraternal twin pairs. Both basic and advanced approaches for estimating heritability concordantly suggested that the trait is substantially heritable. The best-fitting structural equation model indicated that the contributions to individual differences in 2D:4D are 81% additively genetic, 19% nonshared environmental, and 0% shared environmental. Supplemental analyses showed that, consistent with a prediction from sex-hormone transfer theory, women from opposite-sex fraternal twin pairs had significantly lower (more male-typical) 2D:4D than women from same-sex fraternal twin pairs. Directions for research are discussed, such as investigating possible influences of the sex chromosomes on the expression of 2D:4D. Further family studies will be needed to test whether the transmission mode of 2D:4D is consistent with X-linked or Y-linked inheritance. The study of sex chromosome aberrations should indicate whether the presence of additional X or Y chromosomes is associated with 2D:4D levels.

  19. Hand asymmetry in heterosexual and homosexual men and women: relationship to 2D:4D digit ratios and other sexually dimorphic anatomical traits.

    PubMed

    Martin, James T; Puts, David A; Breedlove, S Marc

    2008-02-01

    Sexual differentiation leads to the development of distinctive anatomical structures (e.g., gonads and genitalia); it also produces less obvious anatomical shifts in brain, bones, muscles, etc. This study is a retrospective analysis of growth patterns in the hands in relation to sex and sexual orientation. Using data from three published studies, we analyzed four hand traits in adults: hand width, hand length, second digit length, and fourth digit length. Using these measurements, we derived estimates of trait laterality (directional asymmetry or DA) and developmental instability (fluctuating asymmetry or FA). High FA is a putative indicator of interference with the cellular and molecular mechanisms regulating development. We focused on how these derived variables were related to sex, sexual orientation, and putative markers of early sex steroid exposure (e.g., the second to fourth digit ratio or 2D:4D). Our data point to three principal conclusions. First, individual differences in DA appeared to be a major source of variation in the 2D:4D ratio. The 2D:4D ratios of heterosexual men differed depending on whether they had leftward or rightward DA in their digits. Homosexual women showed the same pattern. Individuals with leftward DA in both digits had lower 2D:4D ratios than those with rightward DA. This effect was absent in heterosexual women and homosexual men. This led to sex differences in 2D:4D and sexual orientation differences in 2D:4D in the leftward DA group, but not in the rightward DA group. The second conclusion was that DA in digit length and hand width varied with sex; women were more likely to have rightward asymmetry than men. Homosexual men and women were generally sex typical in DA. The third conclusion was that homosexuality is unlikely to be a result of increased developmental instability. Although limited in scope, the present evidence actually suggests that homosexuals have lower FA than heterosexuals, raising the question of whether the

  20. [Correlation between basic imaging properties and subjective evaluations of two digital radiographic X-ray systems based on direct-conversion flat panel detector].

    PubMed

    Sakaguchi, Taro; Katayama, Reiji; Morishita, Junji; Sakai, Shinji; Kuroki, Hidefumi; Ohkubo, Seiji; Maeda, Takashi; Hayabuchi, Naofumi

    2010-11-20

    The purpose of this study was to examine the correlation between the basic imaging properties of two digital radiographic X-ray systems with a direct conversion flat-panel detector and their image qualities, which were evaluated by the observer in hard copy and soft copy studies. The subjective image quality was evaluated and compared in terms of the low-contrast detectability and image sharpness in the two digital radiographic X-ray systems. We applied the radiographs of a contrast detail phantom to the evaluation of low-contrast detectability and analyzed the contrast detail diagrams. Finally, low-contrast detectability was evaluated by the image quality figure (IQF) calculated from the contrast detail diagrams. Also, the subjective image sharpness of human dry bones of two systems was examined and evaluated by the normalized-rank method. The results indicated that System A tended to provide superior subjective image quality compared to System B in both observer studies. We also found high correlations between IQFs and basic imaging properties, such as the noise power spectrum (NPS) and the noise equivalent quantum (NEQ). In conclusion, the low-contrast detectability of the two digital radiographic X-ray systems with a direct conversion flat-panel detector corresponded to the NPS and the NEQ in both outputs (soft copy and hard copy). On the other hand, the subjective image sharpness of human dry bones was affected by their noise properties.

  1. An evaluation of the impact of digital imaging on radiographic practice and patient doses

    NASA Astrophysics Data System (ADS)

    Horrocks, J.; Violaki, K.

    2015-09-01

    Direct digital imaging technology was implemented in all areas in general and mobile radiology at Barts and the Royal London Hospitals in 2012. Evidence from recent radiation incident investigations indicates optimum exposure factors are not consistently selected, with the greater dynamic range of the digital detectors allowing sub-optimal practice. To investigate further patient dose data were extracted from the Radiology Information System for adult chest X-ray examinations in 2014, covering over 50,000 studies in the Trust. Chest X-ray examinations were selected as they are low dose but frequent examinations. The patient dose data were evaluated taking into account X-ray system type and detector performance measurements, and individual cases studies were used to highlight where practice can be improved.

  2. The effect of system geometry and dose on the threshold detectable calcification diameter in 2D-mammography and digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Hadjipanteli, Andria; Elangovan, Premkumar; Mackenzie, Alistair; Looney, Padraig T.; Wells, Kevin; Dance, David R.; Young, Kenneth C.

    2017-02-01

    Digital breast tomosynthesis (DBT) is under consideration to replace or to be used in combination with 2D-mammography in breast screening. The aim of this study was the comparison of the detection of microcalcification clusters by human observers in simulated breast images using 2D-mammography, narrow angle (15°/15 projections) and wide angle (50°/25 projections) DBT. The effects of the cluster height in the breast and the dose to the breast on calcification detection were also tested. Simulated images of 6 cm thick compressed breasts were produced with and without microcalcification clusters inserted, using a set of image modelling tools for 2D-mammography and DBT. Image processing and reconstruction were performed using commercial software. A series of 4-alternative forced choice (4AFC) experiments was conducted for signal detection with the microcalcification clusters as targets. Threshold detectable calcification diameter was found for each imaging modality with standard dose: 2D-mammography: 2D-mammography (165  ±  9 µm), narrow angle DBT (211  ±  11 µm) and wide angle DBT (257  ±  14 µm). Statistically significant differences were found when using different doses, but different geometries had a greater effect. No differences were found between the threshold detectable calcification diameters at different heights in the breast. Calcification clusters may have a lower detectability using DBT than 2D imaging.

  3. Physician experience with viewing digital radiographs in an intensive care unit environment.

    PubMed

    Humphrey, L M; Fitzpatrick, K; Paine, S S; Ravin, C E

    1993-02-01

    After several years of continuous operation, the utility of digital viewing stations as assessed by bedside clinicians has been investigated through the distribution of questionnaires to past and present users. The results of the questionnaire have indicated that the bedside physicians prefer using the workstations over handling film. For evaluation of line placements, chest tubes, and pleural effusions, the physicians prefer softcopy display over hardcopy. However, for analysis of air space disease and diagnosis of pneumothorax, images displayed on the workstation were not believed to be as useful as standard hardcopy.

  4. The digital radiographic and computed tomography imaging of two types of explosive devices.

    PubMed

    Galiano Riveros, Eduardo

    2002-12-01

    Two well-established medical imaging methods, digital radiography (DR) and computed tomography (CT), were employed to obtain images of two types of explosive devices, model rocket engines and shotgun shells. The images were evaluated from an airport security perspective. In terms of geometrical shape, the detection probability of the explosive devices appears to be higher with DR imaging, but in terms of the actual explosive compounds in the devices, CT appears to offer a higher detection probability. DR imaging offers a low detection probability for the explosive powder in the shotgun shells, but a rather significant detection probability for the explosive propellant in the model rocket engines.

  5. Doses under automatic exposure control (AEC) for direct digital radiographic (DDR) X-ray systems.

    PubMed

    Bowden, Louise; Faulkner, Ronan; Clancy, Conor; Gallagher, Aoife; Devine, Mark; Gorman, Dermot; O'Reilly, Geraldine; Dowling, Anita

    2011-09-01

    Current guidelines quote tolerances for automatic exposure control (AEC) device performance for X-ray systems as 'Baseline ± X %'. However, in the situation where a baseline figure has not yet been achieved, as in the case of commissioning assessments, this tolerance is not relevant. The purpose of this work is to provide mean doses for direct digital radiography (DDR) X-ray system, operating in AEC, against which comparisons can be made. Dose measurements have been recorded under AEC operation on 29 DDR detectors from three different manufacturers. Two different testing protocols were examined: (1) water equivalent phantoms in front of the DDR detector and (2) aluminium block at the tube head. The average patient exit dose, using the aluminium block was 4.6 μGy with the antiscatter grid in place and 4.0 μGy with the grid removed. Using the water phantoms, the average dose was measured at 17.1 μGy with the antiscatter grid in place and 5.4 μGy with grid removed. Based on these results, it is clear that different testing configurations significantly impact on the measured dose.

  6. The Left Hand Second to Fourth Digit Ratio (2D:4D) Does Not Discriminate World-Class Female Gymnasts from Age Matched Sedentary Girls

    PubMed Central

    Peeters, Maarten W.; Claessens, Albrecht L.

    2012-01-01

    Introduction The second to fourth-digit-ratio (2D:4D), a putative marker of prenatal androgen action and a sexually dimorphic trait, has been suggested to be related with sports performance, although results are not univocal. If this relation exists, it is most likely to be detected by comparing extreme groups on the continuum of sports performance. Methods In this study the 2D:4D ratio of world-class elite female artistic gymnasts (n = 129), competing at the 1987 Rotterdam World-Championships was compared to the 2D:4D ratio of sedentary age-matched sedentary girls (n = 129), alongside with other anthropometric characteristics including other sexually dimorphic traits such as an androgyny index (Bayer & Bayley) and Heath-Carter somatotype components (endomorphy, mesomorphy, ectomorphy) using AN(C)OVA. 2D:4D was measured on X-rays of the left hand. Results Left hand 2D:4D digit ratio in world class elite female gymnasts (0.921±0.020) did not differ significantly from 2D:4D in age-matched sedentary girls (0.924±0.018), either with or without inclusion of potentially confounding covariates such as skeletal age, height, weight, somatotype components or androgyny index. Height (161.9±6.4 cm vs 155.4±6.6 cm p<0.01), weight (53.9±7.6 kg vs 46.2 6.3 kg p<0.01), BMI (20.51±2.41 kg/m2 vs 19.05±1.56 kg/m2), skeletal age (15.2±1.1 y vs 14.5±1.2 y p>0.01), somatotype components (4.0/3.0/2.9 vs 1.7/3.7/3.2 for endomorphy (p<0.01), mesomorphy (p<0.01) and ectomorphy (p<0.05) respectively) all differed significantly between sedentary girls and elite gymnasts. As expressed by the androgyny index, gymnasts have, on average, broader shoulders relative to their hips, compared to the reference sample. Correlations between the 2D:4D ratio and chronological age, skeletal age, and the anthropometric characteristics are low and not significant. Conclusion Although other anthropometric characteristics of sexual dimorphism were significantly different between the two samples

  7. SEX DIFFERENCES IN DIGIT RATIO (2D:4D) AMONG MILITARY AND CIVIL COHORTS AT A MILITARY ACADEMY IN WROCŁAW, POLAND.

    PubMed

    Kociuba, Marek; Kozieł, Slawomir; Chakraborty, Raja

    2016-09-01

    The ratio of second-to-fourth digit length (2D:4D), which is generally higher in women compared with men, is a putative marker of prenatal testosterone (PT) exposure. Lower 2D:4D is linked with greater physical ability and strength, better sporting performance and a propensity towards jobs demanding greater physical ability. The objectives of this paper were to examine the sexual dimorphism in 2D:4D in both hands 1and compare this dimorphism in the students of military and civil courses at the General Kuściuszko Military Academy of Land Forces in Wrocław. The cross-sectional study compared 59 female and 118 male students from the military courses and 53 females and 64 male students from the civil courses. Besides calculating 2D:4D (2D/4D) for each hand, height and weight were also recorded. Physical fitness and endurance were assessed using Eurofit tests. Handgrip strength was measured using a standardized isometric dynamometer. In almost all physical tests, students in the military cohort showed highly significant greater physical ability and strength (e.g. handgrip strength) when compared with the civil cohort. Male participants had a significantly lower 2D:4D than females for each hand, as well as for the average value for both hands. The sexual dimorphism was, however, a little more pronounced in the right hand than in the left. Both sex and course type were significant predictors of 2D:4D. There were significant interactions between sex and the student type. Among females, but not in males, the military cohort had a significantly lower, i.e. more 'masculine', 2D:4D for the left hand and right hand and average for both hands (t=3.290, p<0.001) than the civil cohort. This was not the case in males. However, the sex difference in 2D:4D was only significant among the civil students, and not among the military cadets. In conclusion, higher PT exposure, as represented by a lower 2D:4D, among the Polish females might be an indicator of relatively increased physical

  8. Reconstruction-based 3D/2D image registration.

    PubMed

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2005-01-01

    In this paper we present a novel 3D/2D registration method, where first, a 3D image is reconstructed from a few 2D X-ray images and next, the preoperative 3D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure. Because the quality of the reconstructed image is generally low, we introduce a novel asymmetric mutual information similarity measure, which is able to cope with low image quality as well as with different imaging modalities. The novel 3D/2D registration method has been evaluated using standardized evaluation methodology and publicly available 3D CT, 3DRX, and MR and 2D X-ray images of two spine phantoms, for which gold standard registrations were known. In terms of robustness, reliability and capture range the proposed method outperformed the gradient-based method and the method based on digitally reconstructed radiographs (DRRs).

  9. A Critical Review of the Research on the Extreme Male Brain Theory and Digit Ratio (2D:4D)

    ERIC Educational Resources Information Center

    Teatero, Missy L.; Netley, Charles

    2013-01-01

    Boys are more likely than girls to be diagnosed with an autism spectrum disorder (ASD). The extreme male brain (EMB) theory of ASD suggests that fetal testosterone (FT) exposure may underlie sex differences in autistic traits. A link between the organizational effects of FT on the brain and ASD is often drawn based on research using digit ratio…

  10. High-accuracy 2D digital image correlation measurements using low-cost imaging lenses: implementation of a generalized compensation method

    NASA Astrophysics Data System (ADS)

    Pan, Bing; Yu, Liping; Wu, Dafang

    2014-02-01

    The ideal pinhole imaging model commonly assumed for an ordinary two-dimensional digital image correlation (2D-DIC) system is neither perfect nor stable because of the existence of small out-of-plane motion of the test sample surface that occurred after loading, small out-of-plane motion of the sensor target due to temperature variation of a camera and unavoidable geometric distortion of an imaging lens. In certain cases, these disadvantages can lead to significant errors in the measured displacements and strains. Although a high-quality bilateral telecentric lens has been strongly recommended to be used in the 2D-DIC system as an essential optical component to achieve high-accuracy measurement, it is not generally applicable due to its fixed field of view, limited depth of focus and high cost. To minimize the errors associated with the imperfectness and instability of a common 2D-DIC system using a low-cost imaging lens, a generalized compensation method using a non-deformable reference sample is proposed in this work. With the proposed method, the displacement of the reference sample rigidly attached behind the test sample is first measured using 2D-DIC, and then it is fitted using a parametric model. The fitted parametric model is then used to correct the displacements of the deformed sample to remove the influences of these unfavorable factors. The validity of the proposed compensation method is first verified using out-of-plane translation, out-of-plane rotation, in-plane translation tests and their combinations. Uniaxial tensile tests of an aluminum specimen were also performed to quantitatively examine the strain accuracy of the proposed compensation method. Experiments show that the proposed compensation method is an easy-to-implement yet effective technique for achieving high-accuracy deformation measurement using an ordinary 2D-DIC system.

  11. Effect of image processing version on detection of non-calcification cancers in 2D digital mammography imaging

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Cooke, J.; Given-Wilson, R. M.; Wallis, M. G.; Halling-Brown, M.; Mackenzie, A.; Chakraborty, D. P.; Bosmans, H.; Dance, D. R.; Young, K. C.

    2013-03-01

    Image processing (IP) is the last step in the digital mammography imaging chain before interpretation by a radiologist. Each manufacturer has their own IP algorithm(s) and the appearance of an image after IP can vary greatly depending upon the algorithm and version used. It is unclear whether these differences can affect cancer detection. This work investigates the effect of IP on the detection of non-calcification cancers by expert observers. Digital mammography images for 190 patients were collected from two screening sites using Hologic amorphous selenium detectors. Eighty of these cases contained non-calcification cancers. The images were processed using three versions of IP from Hologic - default (full enhancement), low contrast (intermediate enhancement) and pseudo screen-film (no enhancement). Seven experienced observers inspected the images and marked the location of regions suspected to be non-calcification cancers assigning a score for likelihood of malignancy. This data was analysed using JAFROC analysis. The observers also scored the clinical interpretation of the entire case using the BSBR classification scale. This was analysed using ROC analysis. The breast density in the region surrounding each cancer and the number of times each cancer was detected were calculated. IP did not have a significant effect on the radiologists' judgment of the likelihood of malignancy of individual lesions or their clinical interpretation of the entire case. No correlation was found between number of times each cancer was detected and the density of breast tissue surrounding that cancer.

  12. Computer-aided detection of masses in digital tomosynthesis mammography: combination of 3D and 2D detection information

    NASA Astrophysics Data System (ADS)

    Chan, Heang-Ping; Wei, Jun; Zhang, Yiheng; Moore, Richard H.; Kopans, Daniel B.; Hadjiiski, Lubomir; Sahiner, Berkman; Roubidoux, Marilyn A.; Helvie, Mark A.

    2007-03-01

    We are developing a computer-aided detection (CAD) system for masses on digital breast tomosynthesis mammograms (DBTs). The CAD system includes two parallel processes. In the first process, mass detection and feature analysis are performed in the reconstructed 3D DBT volume. A mass likelihood score is estimated for each mass candidate using a linear discriminant (LDA) classifier. In the second process, mass detection and feature analysis are applied to the individual projection view (PV) images. A mass likelihood score is estimated for each mass candidate using another LDA classifier. The mass likelihood images derived from the PVs are back-projected to the breast volume to estimate the 3D spatial distribution of the mass likelihood scores. The mass likelihood scores estimated by the two processes at the corresponding 3D location are then merged and evaluated using FROC analysis. In this preliminary study, a data set of 52 DBT cases acquired with a GE prototype system at the Massachusetts General Hospital was used. The LDA classifiers with stepwise feature selection were designed with leave-one-case-out resampling. In an FROC analysis, the CAD system for detection in the DBT volume alone achieved test sensitivities of 80% and 90% at an average FP rate of 1.6 and 3.0 per breast, respectively. In comparison, the average FP rates of the combined system were 1.2 and 2.3 per breast, respectively, at the same sensitivities. The combined system is a promising approach to improving mass detection on DBTs.

  13. Cerebral laterality for language is related to adult salivary testosterone levels but not digit ratio (2D:4D) in men: A functional transcranial Doppler ultrasound study.

    PubMed

    Papadatou-Pastou, Marietta; Martin, Maryanne

    2017-03-01

    The adequacy of three competing theories of hormonal effects on cerebral laterality are compared using functional transcranial Doppler sonography (fTCD). Thirty-three adult males participated in the study (21 left-handers). Cerebral lateralization was measured by fTCD using an extensively validated word generation task. Adult salivary testosterone (T) and cortisol (C) concentrations were measured by luminescence immunoassay and prenatal T exposure was indirectly estimated by the somatic marker of 2nd to 4th digit length ratio (2D:4D). A significant quadratic relationship between degree of cerebral laterality for language and adult T concentrations was observed, with enhanced T levels for strong left hemisphere dominance and strong right hemisphere dominance. No systematic effects on laterality were found for cortisol or 2D:4D. Findings suggest that higher levels of T are associated with a relatively attenuated degree of interhemispheric sharing of linguistic information, providing support for the callosal and the sexual differentiation hypotheses rather than the Geschwind, Behan and Galaburda (GBG) hypothesis.

  14. WE-AB-BRA-07: Quantitative Evaluation of 2D-2D and 2D-3D Image Guided Radiation Therapy for Clinical Trial Credentialing, NRG Oncology/RTOG

    SciTech Connect

    Giaddui, T; Yu, J; Xiao, Y; Jacobs, P; Manfredi, D; Linnemann, N

    2015-06-15

    Purpose: 2D-2D kV image guided radiation therapy (IGRT) credentialing evaluation for clinical trial qualification was historically qualitative through submitting screen captures of the fusion process. However, as quantitative DICOM 2D-2D and 2D-3D image registration tools are implemented in clinical practice for better precision, especially in centers that treat patients with protons, better IGRT credentialing techniques are needed. The aim of this work is to establish methodologies for quantitatively reviewing IGRT submissions based on DICOM 2D-2D and 2D-3D image registration and to test the methodologies in reviewing 2D-2D and 2D-3D IGRT submissions for RTOG/NRG Oncology clinical trials qualifications. Methods: DICOM 2D-2D and 2D-3D automated and manual image registration have been tested using the Harmony tool in MIM software. 2D kV orthogonal portal images are fused with the reference digital reconstructed radiographs (DRR) in the 2D-2D registration while the 2D portal images are fused with DICOM planning CT image in the 2D-3D registration. The Harmony tool allows alignment of the two images used in the registration process and also calculates the required shifts. Shifts calculated using MIM are compared with those submitted by institutions for IGRT credentialing. Reported shifts are considered to be acceptable if differences are less than 3mm. Results: Several tests have been performed on the 2D-2D and 2D-3D registration. The results indicated good agreement between submitted and calculated shifts. A workflow for reviewing these IGRT submissions has been developed and will eventually be used to review IGRT submissions. Conclusion: The IROC Philadelphia RTQA center has developed and tested a new workflow for reviewing DICOM 2D-2D and 2D-3D IGRT credentialing submissions made by different cancer clinical centers, especially proton centers. NRG Center for Innovation in Radiation Oncology (CIRO) and IROC RTQA center continue their collaborative efforts to enhance

  15. Evaluation of hand bone loss by digital X-ray radiogrammetry as a complement to clinical and radiographic assessment in early rheumatoid arthritis: results from the SWEFOT trial

    PubMed Central

    2013-01-01

    Background To investigate hand bone loss (HBL) measured by digital X-ray radiogrammetry (DXR) in patients with early rheumatoid arthritis (RA) receiving different treatment regimens, and to evaluate if DXR change rates during the first 12 months correlate with radiological damage after 24 months. Methods From the total SWEFOT trial population, 159 patients had hand radiographs correctly timed and taken with same modality to be analyzed with DXR. All patients started treatment with methotrexate. After 3–4 months, patients with DAS28 > 3.2 were randomized to add sulfasalazine and hydroxychloroquine (triple therapy) or infliximab (MTX + INF). Those with DAS28 ≤3.2 were followed in regular care. Radiographic progression over 24 months was scored according to the Sharp van der Heijde score (SHS) and defined as >5 increase in T-SHS over 24 months. Hand bone mineral density (BMD) was measured by DXR at inclusion and 12 months and a change ≥2.5 mg/cm2/month was used as a cut-off for HBL. Results In the MTX responders, triple therapy, and MTX + INF groups, the proportions with HBL were 4.1%, 22.2% and 16.4%, respectively (p = 0.01), and the mean (SD) radiological progression in these groups was 3.91 (6.72), 7.40 (14.63) and 2.72 (4.55) respectively (p = 0.06). Patients with HBL had significantly greater risk for radiographic progression, compared with patients without HBL (odds ratio 3.09, 95% CI =1.20–7.79, p = 0.02). Conclusions Non-responders to MTX had a significantly greater risk of HBL than MTX-responders, despite the add-on therapies. Patients with HBL during the 12 months had greater risk of radiographic progression after 24 months. Evaluation of HBL may help to identify patients who are at risk of radiographic progression. PMID:23497111

  16. Digital Paper Prints as Replacement for LASER Films: A Study of Intra-Observer Agreement for Wrist Radiographic Findings in Rickets

    PubMed Central

    Jain, Abhinav; Anand, Surinder Pal Singh; Dang, Archana

    2016-01-01

    Introduction Replacement of conventional LASER films with digital paper prints as supplement to radiology reports may serve as an economical and environment friendly method. However, it is essential that such a change does not compromise patient’s intended diagnostic outcome. Aim The aim of this study was to assess the reliability and acceptability of digital paper prints for the radiographic images by the treating physicians and radiologists. Materials and Methods This observational analytical study was done at a tertiary care hospital of New Delhi, India. A total of 58 consecutively ordered wrist radiographs of paediatric patients (6 months to 12 years of age) for ruling out rickets were retrieved from the PACS (Picture Archiving and Communication System). These 58 radiographs, out of which 21 (36.2%) had radiological evidence of rickets over PACS were printed on two different media i.e., LASER films and glossy photographic paper. An objective scoring for the severity of rickets was done on both LASER films and paper prints by six observers independently. Overall comfort level with paper prints was rated on a 1-5 point Likert scale. Data was analysed using STATA 14.0 (Stata Corp, College Station, TX). Results Intra-observer percentage agreement and value of Cohen’s kappa for PACS vs. LASER films and PACS vs. paper prints was equal i.e., 98.3% and 0.97, respectively. Intra-observer agreement between LASER films and paper prints for all six observers was excellent, ranging from 0.92 to 1.00; percentage agreement ranging from 94.8% to 100%. Fracture of ulna/radius present in 4 sets of the X-rays was well demonstrated in both LASER films and paper prints. Comfort level with paper prints was rated as 5 out of 5 by all due to no requirement of any special illuminated view box and dark room. Conclusion This study concludes that the use of paper prints may serve as a reliable alternative to LASER films to communicate the report of wrist radiographs for the treating

  17. An Analysis of Visibility and Anatomic Variations of Mandibular Canal in Digital Panoramic Radiographs of Dentulous and Edentulous Patients in Northern Iran Populations

    PubMed Central

    Nemati, Somayeh; Ashouri Moghadam, Anahita; Dalili Kajan, Zahra; Mohtavipour, Seyedeh Tahereh; Amouzad, Hasan

    2016-01-01

    Statement of the Problem Insufficient information about the anatomical positions and structure of mandibular canal provokes unwanted damage to this important structure of mandible. Purpose The aim of this study was to determine the visibility and anatomical variations of mandibular canal in digital panoramic radiographs of dentulous and edentulous patients in a sample of Iranian population. Materials and Method In this retrospective-analytical research, 249 digital panoramic radiographs in dentulous group and 126 in edentulous group were studied by an expert oral and maxillofacial radiologist. In both groups, the visibility of canal borders in anterior, middle, and posterior areas were examined. In dentulous group, the distance between the canal and apex of the first and second molars were measured. Canal-to-alveolar crest distance and lower mandibular border was measured in three different points for both groups. Finally, the upper-lower positions of canals were determined. Results In both groups, most visibility occurred in 1/3 of posterior and the least visibility was detected in 1/3 of anterior, with the intermediate being the most visible part (Type 2). There was no significant difference between the left and right sides in all cases. In dentulous group, no correlation was found between the visibility, age, and gender (p> 0.05); however, canal position was related to gender (p= 0.03 and p= 0.04 in right and left sides, respectively). High position was more frequent in females and intermediate position was more common in males. In edentulous group, no correlation was found between age, gender, and canal position (p> 0.05). Conclusion The most visibility of mandibular canal was in its third posterior and the least was in its third anterior part. Although the middle position of canal was more frequently visible than the high position in this study, it does not refute the possibility of damaging the mandibular canal in critical surgeries. PMID:27284556

  18. Analysis and Visualization of 2D and 3D Grain and Pore Size ofFontainebleau Sandstone Using Digital Rock Physics

    NASA Astrophysics Data System (ADS)

    Latief, FDE

    2016-08-01

    Fontainebleau sandstone is sandstone found in one of the cities in France. This sandstone has unique characteristics, which is a clean-fme sandstone, composed of 99% quartz, virtually devoid of clay, with the grain size of about 200 μm. Fontainebleau sandstone is widely used as a reference in the study of rock microstructure analysis and modelling. In this work analysis regarding the grain and pore size of Fontainebleau is presented. Calculation of 2D pore size and grain size distribution were done on the 299 slice of digital image of the Fontainebleau sandstone using Feret's diameters, equivalent diameters (d = 4A/P), and by means of local thickness/separation using plate model. For the 3D grain and pore size distribution, calculation of local thickness and local separation of the structure were used. Two dimensional analysis by means of Feret's diameter and equivalent diameter reveal that both grain and pore size distributions are in the form of reverse-J shaped (right skewed) while the local thickness/separation approach produces almost similar to symmetric Gaussian distribution. Three dimensional analysis produces fairly symmetric Gaussian distribution for both the grain and pore size. Further image processing were conducted and were succeed in producing three dimensional visual of the colour coded structure thickness (grain related) and structure separation (pore related).

  19. Potential sources of quantification error when retrospectively assessing metacarpal bone loss from historical radiographs by using digital X-ray radiogrammetry: an experimental study.

    PubMed

    Kälvesten, Johan; Brismar, Torkel B; Persson, Anders

    2014-01-01

    During the past 15 yr, digital X-ray radiogrammetry (DXR) has been used to measure metacarpal bone mineral density (BMD). BMD is often measured in existing cohorts where X-ray images were not acquired in accordance with the DXR imaging protocol (DIP). The purpose of the present study was to analyze how deviations from DIP in historical radiographs may affect the reproducibility of DXR-BMD measurements. Cadaver hand phantoms were used to conduct repeat measurements of deviations from DIP with respect to voltage, exposure, lateral displacement, supination, combination of lateral displacement and supination or rotation, extension of the wrist, and edge enhancement. Direct digital radiography (Aristos; Siemens Healthcare, Erlangen, Germany) was used for image acquisition and dxr-online (Sectra, Linköping, Sweden) for DXR-BMD measurements. The influence of the tested deviations from DIP ranged from 0 to 32.5 mg/cm(2) (0-6.8%). On repetition with the same specimen, none of the deviations resulted in a within-specimen reproducibility error greater than 2 mg/cm(2) (0.4%, equivalent to a T-score of 0.042). Among the tested deviations, all except tube voltage had a magnitude greater than the normal measurement noise for the technique and must therefore be considered when planning a study based on historical images.

  20. 2D/3D Image Registration using Regression Learning

    PubMed Central

    Chou, Chen-Rui; Frederick, Brandon; Mageras, Gig; Chang, Sha; Pizer, Stephen

    2013-01-01

    In computer vision and image analysis, image registration between 2D projections and a 3D image that achieves high accuracy and near real-time computation is challenging. In this paper, we propose a novel method that can rapidly detect an object’s 3D rigid motion or deformation from a 2D projection image or a small set thereof. The method is called CLARET (Correction via Limited-Angle Residues in External Beam Therapy) and consists of two stages: registration preceded by shape space and regression learning. In the registration stage, linear operators are used to iteratively estimate the motion/deformation parameters based on the current intensity residue between the target projec-tion(s) and the digitally reconstructed radiograph(s) (DRRs) of the estimated 3D image. The method determines the linear operators via a two-step learning process. First, it builds a low-order parametric model of the image region’s motion/deformation shape space from its prior 3D images. Second, using learning-time samples produced from the 3D images, it formulates the relationships between the model parameters and the co-varying 2D projection intensity residues by multi-scale linear regressions. The calculated multi-scale regression matrices yield the coarse-to-fine linear operators used in estimating the model parameters from the 2D projection intensity residues in the registration. The method’s application to Image-guided Radiation Therapy (IGRT) requires only a few seconds and yields good results in localizing a tumor under rigid motion in the head and neck and under respiratory deformation in the lung, using one treatment-time imaging 2D projection or a small set thereof. PMID:24058278

  1. Doses measured using AEC on direct digital radiographic (DDR) X-rays systems: updated results with an RP 162 perspective.

    PubMed

    Bowden, L; Faulkner, R; Gallagher, A; O'Connor, U; Walsh, C; Dowling, A; O'Reilly, G

    2013-02-01

    As digital technology in diagnostic radiology systems becomes more prevalent, there is a need to provide comparative dose information for these new systems. This is needed in particular for testing the automatic exposure control (AEC) devices on direct digital radiography (DDR) systems as there is no consensus on the receptor dose level in the current guidelines. The new European Commission RP 162 document sets the suspension level for the 'verification of kerma at receptor entrance in computed radiography and DDR systems under AEC' as ≥10 µGy. This document also notes that alternate methodologies are acceptable, and may require adjustment in the suspension level if used. This study provides a range of typical doses under AEC for DDR systems, for a variety measurement methodologies, including that described in RP 162.

  2. A radiolucent chair for sitting-posture radiographs in non-ambulatory children: use in biplanar digital slot-scanning.

    PubMed

    Bouloussa, Houssam; Dubory, Arnaud; Seiler, Catherine; Morel, Baptiste; Bachy, Manon; Vialle, Raphaël

    2015-11-01

    EOS imaging (EOS System; EOS imaging, Paris, France) enables fast 2-D/3-D imaging of children in standing load-bearing position. Non-ambulatory children with neuromuscular scoliosis need evaluation of their spinal balance while in a normal daily position. We designed a customized chair fitting the EOS patient-area dimensions to obtain images in natural sitting postures. The chair is a 360° rotating orthopaedic chair made of fully radiolucent polyethylene and equipped with an adjustable headrest and three-point belts. Out of 41 consecutive patients, 36 (88%, 95% confidence interval 74-96%) had successful imaging. In most patients with severe neuromuscular trunk deformities, the EOS system combined with our chair was useful for assessing preoperative trunk collapse, pelvic obliquity and postoperative corrections in all planes. This specific device changed our daily practice for the assessment of spinal deformities in non-ambulatory patients.

  3. Second to fourth digit length ratio (2D:4D) and adult sex hormone levels: new data and a meta-analytic review.

    PubMed

    Hönekopp, Johannes; Bartholdt, Luise; Beier, Lothar; Liebert, Andreas

    2007-05-01

    The relative length of the second (index) to the fourth (ring) finger (2D:4D) is a putative negative correlate of prenatal testosterone (T) exposure. Therefore, 2D:4D (and to a lesser extent D(r-l), the difference between 2D:4D in the right hand and in the left hand) has often been used to study effects of prenatal androgenization on human behavior and cognition. However, evidence suggests that 2D:4D may also be related to levels of circulating sex hormones in adults. This would question the validity of 2D:4D as a means of studying the effects of prenatal sex hormones. Here we present new data from two non-clinical samples (64 women and 102 men) regarding the relationships of 2D:4D and D(r-l) with circulating sex hormone levels. We then present a meta-analytic review of all the present evidence regarding this issue. The results suggest that, in the normal population, 2D:4D and D(r-l) are not associated with adult sex hormone levels. The findings from this current study add to the growing body of evidence demonstrating that 2D:4D is a suitable tool to study the effects of prenatal androgenization on human behavior and cognition.

  4. Can Sex Differences in Science Be Tied to the Long Reach of Prenatal Hormones? Brain Organization Theory, Digit Ratio (2D/4D), and Sex Differences in Preferences and Cognition

    PubMed Central

    Valla, Jeffrey; Ceci, Stephen J.

    2011-01-01

    Brain organization theory posits a cascade of physiological and behavioral changes initiated and shaped by prenatal hormones. Recently, this theory has been associated with outcomes including gendered toy preference, 2D/4D digit ratio, personality characteristics, sexual orientation, and cognitive profile (spatial, verbal, and mathematical abilities). We examine the evidence for this claim, focusing on 2D/4D and its putative role as a biomarker for organizational features that influence cognitive abilities/interests predisposing males toward mathematically and spatially intensive careers. Although massive support exists for early brain organization theory overall, there are myriad inconsistencies, alternative explanations, and outright contradictions that must be addressed while still taking the entire theory into account. Like a fractal within the larger theory, the 2D/4D hypothesis mirrors this overall support on a smaller scale while likewise suffering from inconsistencies (positive, negative, and sex-dependent correlations), alternative explanations (2D/4D related to spatial preferences rather than abilities per se), and contradictions (feminine 2D/4D in men associated with higher spatial ability). Using the debate over brain organization theory as the theoretical stage, we focus on 2D/4D evidence as an increasingly important player on this stage, a demonstrative case in point of the evidential complexities of the broader debate, and an increasingly important topic in its own right. PMID:22164187

  5. The relationship between second-to-fourth digit (2D:4D) ratios and problematic and pathological Internet use among Turkish university students.

    PubMed

    Canan, Fatih; Karaca, Servet; Düzgün, Melike; Erdem, Ayşe Merve; Karaçaylı, Esranur; Topan, Nur Begüm; Lee, Sang-Kyu; Zhai, Zu Wei; Kuloğlu, Murat; Potenza, Marc N

    2017-03-01

    Background and aims The ratio of the second and fourth fingers (2D:4D ratio) is a sexually dimorphic trait, with men tending to have lower values than women. This ratio has been related to prenatal testosterone concentrations and addictive behaviors including problematic video-gaming. We aimed to investigate the possible association between 2D:4D ratios and Internet addiction and whether such a relationship would be independent of impulsivity. Methods A total of 652 university students (369 women, 283 men), aged 17-27 years, were enrolled in the study. Problematic and pathological Internet use (PPIU) was assessed using the Internet Addiction Test (IAT). The participants also completed the Barratt Impulsiveness Scale (version 11; BIS-11) and had their 2D:4D ratios measured. Results 2D:4D ratios were not significantly different in women with PPIU and in those with adaptive Internet use (AIU). Men with PPIU exhibited lower 2D:4D ratios on both hands when compared with those with AIU. Correlation analysis revealed that 2D:4D ratios on both hands were negatively correlated with IAT scores among men, but not among women. The multiple linear regression analysis revealed that age, duration of weekly Internet use, impulsiveness, and 2D:4D ratios on the right hand were independently associated with IAT scores among men, and impulsivity did not mediate the relationship between 2D:4D ratios and PPIU. Conclusions For men, 2D:4D ratios on the right hand were inversely correlated with Internet addiction severity even after controlling for individual differences in impulsivity. These findings suggest that high prenatal testosterone levels may contribute to the occurrence of PPIU among men.

  6. The Ratio of Second to Fourth Digit Length (2D:4D) and Coronary Artery Disease in a Han Chinese Population

    PubMed Central

    Wu, Xing-li; Yang, Ding-you; Chai, Wen-hui; Jin, Ming-lei; Zhou, Xing-chun; Peng, Li; Zhao, Yu-sheng

    2013-01-01

    Background: The association between index finger to ring finger length ratio (2D:4D) and cardiac disorders has been reported, however it has not been discussed in terms of coronary artery disease (CAD). We investigated whether 2D:4D could be used as a marker for predisposition to CAD as assessed by coronary angiography in Chinese men and women. Methods: This study included 1764 persons divided into 4 groups, 441 cases with CAD and 441 persons without CAD as control in each sex of the same age. Finger lengths were measured twice for both hands using electronic calipers. Student t test was used to detect the difference of 2D:4D among groups. The receiver operator characteristic curves (ROCs) were used to detect the diagnostic effect of 2D:4D for CAD. Results: There were no significant differences in age among the four groups. A significant difference of 2D:4D ratios between right and left hand were observed only in men in both control and CAD groups. On the right hand in the control group and on both hands in the CAD group, the 2D:4D ratios were higher in women than in men (all, P < 0.001). In men with CAD, mean 2D:4D was higher than mean 2D:4D in control men (right hand 0.962±0.042:0.927±0.038; left hand 0.950±0.044:0.934±0.048; both hands, P < 0.001), but this was not observed in women. No relationship was found between 2D:4D and age (all, P >0.05). The area under the curve of right hand 2D:4D in male was 0.72 (95% CI 0.683-0.753, p<0.001), while it was 0.602 (95% CI 0.565-0.639, p<0.001) in left hand. Conclusions: The present study showed an association between high 2D:4D ratio and CAD in both hands in men. There were no significant differences in mean 2D:4D between women with CAD and controls. PMID:24046536

  7. WE-G-204-08: Optimized Digital Radiographic Technique for Lost Surgical Devices/Needle Identification

    SciTech Connect

    Gorman, A; Seabrook, G; Brakken, A; Dubois, M; Marn, C; Wilson, C; Jacobson, D; Liu, Y

    2015-06-15

    Purpose: Small surgical devices and needles are used in many surgical procedures. Conventionally, an x-ray film is taken to identify missing devices/needles if post procedure count is incorrect. There is no data to indicate smallest surgical devices/needles that can be identified with digital radiography (DR), and its optimized acquisition technique. Methods: In this study, the DR equipment used is a Canon RadPro mobile with CXDI-70c wireless DR plate, and the same DR plate on a fixed Siemens Multix unit. Small surgical devices and needles tested include Rubber Shod, Bulldog, Fogarty Hydrogrip, and needles with sizes 3-0 C-T1 through 8-0 BV175-6. They are imaged with PMMA block phantoms with thickness of 2–8 inch, and an abdomen phantom. Various DR techniques are used. Images are reviewed on the portable x-ray acquisition display, a clinical workstation, and a diagnostic workstation. Results: all small surgical devices and needles are visible in portable DR images with 2–8 inch of PMMA. However, when they are imaged with the abdomen phantom plus 2 inch of PMMA, needles smaller than 9.3 mm length can not be visualized at the optimized technique of 81 kV and 16 mAs. There is no significant difference in visualization with various techniques, or between mobile and fixed radiography unit. However, there is noticeable difference in visualizing the smallest needle on a diagnostic reading workstation compared to the acquisition display on a portable x-ray unit. Conclusion: DR images should be reviewed on a diagnostic reading workstation. Using optimized DR techniques, the smallest needle that can be identified on all phantom studies is 9.3 mm. Sample DR images of various small surgical devices/needles available on diagnostic workstation for comparison may improve their identification. Further in vivo study is needed to confirm the optimized digital radiography technique for identification of lost small surgical devices and needles.

  8. Age at menarche and digit ratio (2D:4D): relationships with body dissatisfaction, drive for thinness, and bulimia symptoms in women.

    PubMed

    Oinonen, Kirsten A; Bird, Jessica L

    2012-03-01

    This study examined the hypothesis that lower prenatal androgen exposure and earlier puberty are associated with more dysfunctional eating attitudes and behaviors. Relationships between both age at menarche (AAM) and 2D:4D (a marker of prenatal androgen exposure), and EDI-2-Body Dissatisfaction, EDI-2-Drive for Thinness, and EDI-2-Bulimia scores, were examined in women using correlations and regressions. Earlier menarche was associated with higher drive for thinness after controlling for BMI and negative affect, but only in women who were not exclusively heterosexual. Higher 2D:4D was associated with higher Bulimia and Body Dissatisfaction scores, but only in exclusively heterosexual women, and relationships disappeared when covariates were controlled. Later AAM and higher 2D:4D were unique predictors of higher Bulimia scores for exclusive heterosexuals when BMI was controlled. These findings suggest future research should examine sexual orientation as a mediator or moderator of prenatal and postnatal organizational hormonal effects on women's disordered eating attitudes and behaviors.

  9. Computer enhancement of radiographs

    NASA Technical Reports Server (NTRS)

    Dekaney, A.; Keane, J.; Desautels, J.

    1973-01-01

    Examination of three relevant noise processes and the image degradation associated with Marshall Space Flight Center's (MSFC) X-ray/scanning system was conducted for application to computer enhancement of radiographs using MSFC's digital filtering techniques. Graininess of type M, R single coat and R double coat X-ray films was quantified as a function of density level using root-mean-square (RMS) granularity. Quantum mottle (including film grain) was quantified as a function of the above film types, exposure level, specimen material and thickness, and film density using RMS granularity and power spectral density (PSD). For various neutral-density levels the scanning device used in digital conversion of radiographs was examined for noise characteristics which were quantified by RMS granularity and PSD. Image degradation of the entire pre-enhancement system (MG-150 X-ray device; film; and optronics scanner) was measured using edge targets to generate modulation transfer functions (MTF). The four parameters were examined as a function of scanning aperture sizes of approximately 12.5 25 and 50 microns.

  10. Interpretation of dental radiographs.

    PubMed

    Woodward, Tony M

    2009-02-01

    Interpretation of dental radiographs is fairly straightforward, with a handful of common patterns making up the majority of pathology. This article covers normal radiographic anatomy, endodontic disease, periodontal disease, neoplastic changes, tooth resorption, caries, and radiographic signs of oral trauma.

  11. Pilot Study on the Detection of Simulated Lesions Using a 2D and 3D Digital Full-Field Mammography System with a Newly Developed High Resolution Detector Based on Two Shifts of a-Se.

    PubMed

    Schulz-Wendtland, R; Bani, M; Lux, M P; Schwab, S; Loehberg, C R; Jud, S M; Rauh, C; Bayer, C M; Beckmann, M W; Uder, M; Fasching, P A; Adamietz, B; Meier-Meitinger, M

    2012-05-01

    Purpose: Experimental study of a new system for digital 2D and 3D full-field mammography (FFDM) using a high resolution detector based on two shifts of a-Se. Material and Methods: Images were acquired using the new FFDM system Amulet® (FujiFilm, Tokio, Japan), an a-Se detector (receptor 24 × 30 cm(2), pixel size 50 µm, memory depth 12 bit, spatial resolution 10 lp/mm, DQE > 0.50). Integrated in the detector is a new method for data transfer, based on optical switch technology. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152A (Radiation Measurement Inc., Middleton, WI, USA) and the same parameters and exposure data (Tungsten, 100 mAs, 30 kV) were consistently used. We acquired 3 different pairs of images in the c-c and ml planes (2D) and in the c-c and c-c planes with an angle of 4 degrees (3D). Five radiologists experienced in mammography (experience ranging from 3 months to more than 5 years) analyzed the images (monitoring) which had been randomly encoded (random generator) with regard to the recognition of details such as specks of aluminum oxide (200-740 µm), nylon fibers (0.4-1.6 mm) and round lesions/masses (diameters 5-14 mm), using special linear glasses for 3D visualization, and compared the results. Results: A total of 225 correct positive decisions could be detected: we found 222 (98.7 %) correct positive results for 2D and 3D visualization in each case. Conclusion: The results of this phantom study showed the same detection rates for both 2D and 3D imaging using full field digital mammography. Our results must be confirmed in further clinical trials.

  12. 3D-2D Deformable Image Registration Using Feature-Based Nonuniform Meshes

    PubMed Central

    Guo, Xiaohu; Cai, Yiqi; Yang, Yin; Wang, Jing; Jia, Xun

    2016-01-01

    By using prior information of planning CT images and feature-based nonuniform meshes, this paper demonstrates that volumetric images can be efficiently registered with a very small portion of 2D projection images of a Cone-Beam Computed Tomography (CBCT) scan. After a density field is computed based on the extracted feature edges from planning CT images, nonuniform tetrahedral meshes will be automatically generated to better characterize the image features according to the density field; that is, finer meshes are generated for features. The displacement vector fields (DVFs) are specified at the mesh vertices to drive the deformation of original CT images. Digitally reconstructed radiographs (DRRs) of the deformed anatomy are generated and compared with corresponding 2D projections. DVFs are optimized to minimize the objective function including differences between DRRs and projections and the regularity. To further accelerate the above 3D-2D registration, a procedure to obtain good initial deformations by deforming the volume surface to match 2D body boundary on projections has been developed. This complete method is evaluated quantitatively by using several digital phantoms and data from head and neck cancer patients. The feature-based nonuniform meshing method leads to better results than either uniform orthogonal grid or uniform tetrahedral meshes. PMID:27019849

  13. 3D-2D Deformable Image Registration Using Feature-Based Nonuniform Meshes.

    PubMed

    Zhong, Zichun; Guo, Xiaohu; Cai, Yiqi; Yang, Yin; Wang, Jing; Jia, Xun; Mao, Weihua

    2016-01-01

    By using prior information of planning CT images and feature-based nonuniform meshes, this paper demonstrates that volumetric images can be efficiently registered with a very small portion of 2D projection images of a Cone-Beam Computed Tomography (CBCT) scan. After a density field is computed based on the extracted feature edges from planning CT images, nonuniform tetrahedral meshes will be automatically generated to better characterize the image features according to the density field; that is, finer meshes are generated for features. The displacement vector fields (DVFs) are specified at the mesh vertices to drive the deformation of original CT images. Digitally reconstructed radiographs (DRRs) of the deformed anatomy are generated and compared with corresponding 2D projections. DVFs are optimized to minimize the objective function including differences between DRRs and projections and the regularity. To further accelerate the above 3D-2D registration, a procedure to obtain good initial deformations by deforming the volume surface to match 2D body boundary on projections has been developed. This complete method is evaluated quantitatively by using several digital phantoms and data from head and neck cancer patients. The feature-based nonuniform meshing method leads to better results than either uniform orthogonal grid or uniform tetrahedral meshes.

  14. ProgRes 3000: a digital color camera with a 2-D array CCD sensor and programmable resolution up to 2994 x 2320 picture elements

    NASA Astrophysics Data System (ADS)

    Lenz, Reimar K.; Lenz, Udo

    1990-11-01

    A newly developed imaging principle two dimensional microscanning with Piezo-controlled Aperture Displacement (PAD) allows for high image resolutions. The advantages of line scanners (high resolution) are combined with those of CCD area sensors (high light sensitivity geometrical accuracy and stability easy focussing illumination control and selection of field of view by means of TV real-time imaging). A custom designed sensor optimized for small sensor element apertures and color fidelity eliminates the need for color filter revolvers or mechanical shutters and guarantees good color convergence. By altering the computer controlled microscan patterns spatial and temporal resolution become interchangeable their product being a constant. The highest temporal resolution is TV real-time (50 fields/sec) the highest spatial resolution is 2994 x 2320 picture elements (Pels) for each of the three color channels (28 MBytes of raw image data in 8 see). Thus for the first time it becomes possible to take 35mm slide quality still color images of natural 3D scenes by purely electronic means. Nearly " square" Pels as well as hexagonal sampling schemes are possible. Excellent geometrical accuracy and low noise is guaranteed by sensor element (Sel) synchronous analog to digital conversion within the camera head. The cameras principle of operation and the procedure to calibrate the two-dimensional piezo-mechanical motion with an accuracy of better than O. 2. tm RMSE in image space is explained. The remaining positioning inaccuracy may be further

  15. Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images

    PubMed Central

    Harrison, Deed E.; Janik, Tadeusz J.; Cailliet, Rene; Normand, Martin C.; Perron, Denise L.; Ferrantelli, Joseph R

    2006-01-01

    Since thoracic cage posture affects lumbar spine coupling and loads on the spinal tissues and extremities, a scientific analysis of upright posture is needed. Common posture analyzers measure human posture as displacements from a plumb line, while the PosturePrint™ claims to measure head, rib cage, and pelvic postures as rotations and translations. In this study, it was decided to evaluate the validity of the PosturePrint™ Internet computer system’s analysis of thoracic cage postures. In a university biomechanics laboratory, photographs of a mannequin thoracic cage were obtained in different postures on a stand in front of a digital camera. For each mannequin posture, three photographs were obtained (left lateral, right lateral, and AP). The mannequin thoracic cage was placed in 68 different single and combined postures (requiring 204 photographs) in five degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion–extension (Rx), and anterior–posterior translation (Tz). The PosturePrint™ system requires 13 reflective markers to be placed on the subject (mannequin) during photography and 16 additional “click-on” markers via computer mouse before a set of three photographs is analyzed by the PosturePrint™ computer system over the Internet. Errors were the differences between the positioned mannequin and the calculated positions from the computer system. Average absolute value errors were obtained by comparing the exact inputted posture to the PosturePrint™’s computed values. Mean and standard deviation of computational errors for sagittal displacements of the thoracic cage were Rx=0.3±0.1°, Tz=1.6±0.7 mm, and for frontal view displacements were Ry=1.2±1.0°, Rz=0.6±0.4°, and Tx=1.5±0.6 mm. The PosturePrint™ system is sufficiently accurate in measuring thoracic cage postures in five degrees of freedom on a mannequin indicating the need for a further study on human subjects. PMID:16547756

  16. Gradient-based 3D-2D registration of cerebral angiograms

    NASA Astrophysics Data System (ADS)

    Mitrović, Uroš; Markelj, Primož; Likar, Boštjan; Miloševič, Zoran; Pernuš, Franjo

    2011-03-01

    Endovascular treatment of cerebral aneurysms and arteriovenous malformations (AVM) involves navigation of a catheter through the femoral artery and vascular system into the brain and into the aneurysm or AVM. Intra-interventional navigation utilizes digital subtraction angiography (DSA) to visualize vascular structures and X-ray fluoroscopy to localize the endovascular components. Due to the two-dimensional (2D) nature of the intra-interventional images, navigation through a complex three-dimensional (3D) structure is a demanding task. Registration of pre-interventional MRA, CTA, or 3D-DSA images and intra-interventional 2D DSA images can greatly enhance visualization and navigation. As a consequence of better navigation in 3D, the amount of required contrast medium and absorbed dose could be significantly reduced. In the past, development and evaluation of 3D-2D registration methods received considerable attention. Several validation image databases and evaluation criteria were created and made publicly available in the past. However, applications of 3D-2D registration methods to cerebral angiograms and their validation are rather scarce. In this paper, the 3D-2D robust gradient reconstruction-based (RGRB) registration algorithm is applied to CTA and DSA images and analyzed. For the evaluation purposes five image datasets, each comprised of a 3D CTA and several 2D DSA-like digitally reconstructed radiographs (DRRs) generated from the CTA, with accurate gold standard registrations were created. A total of 4000 registrations on these five datasets resulted in mean mTRE values between 0.07 and 0.59 mm, capture ranges between 6 and 11 mm and success rates between 61 and 88% using a failure threshold of 2 mm.

  17. Finger bone immaturity and 2D:4D ratio measurement error in the assessment of the hyperandrogenic hypothesis for the etiology of autism spectrum disorders.

    PubMed

    Bloom, Michael S; Houston, Allison S; Mills, James L; Molloy, Cynthia A; Hediger, Mary L

    2010-06-01

    Emerging hypotheses suggest a causal role for prenatal androgen exposure in some cases of autism spectrum disorders (ASD). The ratios of the lengths of the bones of the 2nd to the 4th digit (2D:4D) are purported to be markers for prenatal androgen exposure and to be established early in gestation. Elongation of the 4th digit in response to testosterone is said to reduce 2D:4D in males versus females. We examined the ratios of bones from the left hand radiographs of 75 boys and 6 girls 4-8 years of age, diagnosed with ASD, to evaluate digit ratio as a marker for gestational androgen exposure. Contrary to our expectations, girls had reduced 2D:4D compared to boys but the difference was not significant (Cohen's D 0.51-0.66, P>0.05). The limited sample size for this study and the absence of a referent group precluded providing robust estimates for girls and identifying possible statistical differences between the sexes. Tanner-Whitehouse 3 (TW3) rating of finger bone growth suggested relative immaturity of the 4th relative to the 2nd digits. Positive correlations were detected for 2D:4D ratios, body mass index (r=0.23, P=0.039), chronologic age (r=0.35, P=0.001), and skeletal age (r=0.42, P<0.0001). The TW3 ratings and associations between 2D:4D ratios and indicators of growth suggest that digits develop at different rates. This asynchronous development may produce differences in 2D:4D over time which could lead to erroneous interpretation of androgen exposure in utero among young ASD children.

  18. Vertical 2D Heterostructures

    NASA Astrophysics Data System (ADS)

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  19. Visual simulation of radiographs

    SciTech Connect

    Laguna, G.

    1985-01-18

    A method for computer simulation of radiographs has been added to the LLNL version of the solid modeler TIPS-1 (Technical Information Processing System-1). This new tool will enable an engineer to compare an actual radiograph of a solid to its computer-generated counterpart. The appearance of discrepancies between the two can be an indication of flaws in the solid object. Simulated radiographs can also be used to preview the placement of x-ray sources to focus on areas of concern before actual radiographs are made.

  20. Clinical Assessment of 2D/3D Registration Accuracy in 4 Major Anatomic Sites Using On-Board 2D Kilovoltage Images for 6D Patient Setup.

    PubMed

    Li, Guang; Yang, T Jonathan; Furtado, Hugo; Birkfellner, Wolfgang; Ballangrud, Åse; Powell, Simon N; Mechalakos, James

    2015-06-01

    To provide a comprehensive assessment of patient setup accuracy in 6 degrees of freedom (DOFs) using 2-dimensional/3-dimensional (2D/3D) image registration with on-board 2-dimensional kilovoltage (OB-2 DkV) radiographic images, we evaluated cranial, head and neck (HN), and thoracic and abdominal sites under clinical conditions. A fast 2D/3D image registration method using graphics processing unit GPU was modified for registration between OB-2 DkV and 3D simulation computed tomography (simCT) images, with 3D/3D registration as the gold standard for 6 DOF alignment. In 2D/3D registration, body roll rotation was obtained solely by matching orthogonal OB-2 DkV images with a series of digitally reconstructed radiographs (DRRs) from simCT with a small rotational increment along the gantry rotation axis. The window/level adjustments for optimal visualization of the bone in OB-2 DkV and DRRs were performed prior to registration. Ideal patient alignment at the isocenter was calculated and used as an initial registration position. In 3D/3D registration, cone-beam CT (CBCT) was aligned to simCT on bony structures using a bone density filter in 6DOF. Included in this retrospective study were 37 patients treated in 55 fractions with frameless stereotactic radiosurgery or stereotactic body radiotherapy for cranial and paraspinal cancer. A cranial phantom was used to serve as a control. In all cases, CBCT images were acquired for patient setup with subsequent OB-2 DkV verification. It was found that the accuracy of the 2D/3D registration was 0.0 ± 0.5 mm and 0.1° ± 0.4° in phantom. In patient, it is site dependent due to deformation of the anatomy: 0.2 ± 1.6 mm and -0.4° ± 1.2° on average for each dimension for the cranial site, 0.7 ± 1.6 mm and 0.3° ± 1.3° for HN, 0.7 ± 2.0 mm and -0.7° ± 1.1° for the thorax, and 1.1 ± 2.6 mm and -0.5° ± 1.9° for the abdomen. Anatomical deformation and presence of soft tissue in 2D/3D registration affect the consistency with

  1. Clinical Assessment of 2D/3D Registration Accuracy in 4 Major Anatomic Sites Using On-Board 2D Kilovoltage Images for 6D Patient Setup

    PubMed Central

    Li, Guang; Yang, T. Jonathan; Furtado, Hugo; Birkfellner, Wolfgang; Ballangrud, Åse; Powell, Simon N.; Mechalakos, James

    2015-01-01

    To provide a comprehensive assessment of patient setup accuracy in 6 degrees of freedom (DOFs) using 2-dimensional/3-dimensional (2D/3D) image registration with on-board 2-dimensional kilovoltage (OB-2DkV) radiographic images, we evaluated cranial, head and neck (HN), and thoracic and abdominal sites under clinical conditions. A fast 2D/3D image registration method using graphics processing unit GPU was modified for registration between OB-2DkV and 3D simulation computed tomography (simCT) images, with 3D/3D registration as the gold standard for 6DOF alignment. In 2D/3D registration, body roll rotation was obtained solely by matching orthogonal OB-2DkV images with a series of digitally reconstructed radiographs (DRRs) from simCT with a small rotational increment along the gantry rotation axis. The window/level adjustments for optimal visualization of the bone in OB-2DkV and DRRs were performed prior to registration. Ideal patient alignment at the isocenter was calculated and used as an initial registration position. In 3D/3D registration, cone-beam CT (CBCT) was aligned to simCT on bony structures using a bone density filter in 6DOF. Included in this retrospective study were 37 patients treated in 55 fractions with frameless stereotactic radiosurgery or stereotactic body radiotherapy for cranial and paraspinal cancer. A cranial phantom was used to serve as a control. In all cases, CBCT images were acquired for patient setup with subsequent OB-2DkV verification. It was found that the accuracy of the 2D/3D registration was 0.0 ± 0.5 mm and 0.1° ± 0.4° in phantom. In patient, it is site dependent due to deformation of the anatomy: 0.2 ± 1.6 mm and −0.4° ± 1.2° on average for each dimension for the cranial site, 0.7 ± 1.6 mm and 0.3° ± 1.3° for HN, 0.7 ± 2.0 mm and −0.7° ± 1.1° for the thorax, and 1.1 ± 2.6 mm and −0.5° ± 1.9° for the abdomen. Anatomical deformation and presence of soft tissue in 2D/3D registration affect the consistency with

  2. 2D semiconductor optoelectronics

    NASA Astrophysics Data System (ADS)

    Novoselov, Kostya

    The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.

  3. Radiographic film package

    SciTech Connect

    Muylle, W. E.

    1985-08-27

    A radiographic film package for non-destructive testing, comprising a radiographic film sheet, an intensifying screen with a layer of lead bonded to a paper foil, and a vacuum heat-sealed wrapper with a layer of aluminum and a heat-sealed easy-peelable thermoplastic layer.

  4. Are Panoramic Radiographs Reliable to Diagnose Mild Alveolar Bone Resorption?

    PubMed Central

    Semenoff, Larissa; Semenoff, Tereza Aparecida Delle; Pedro, Fabio Luiz Miranda; Volpato, Evaristo Ricci; Machado, Maria Aparecida de Andrade Moreira; Borges, Álvaro Henrique; Semenoff-Segundo, Alex

    2011-01-01

    It is extremely important to assess variations between the most used radiographs in dental practice, since minimum distortion on obtained images may change diagnosis, treatment plan, and prognosis for the patient. For this, the distance between the enamel-cementum junction and the alveolar bone crest was measured on conventional and digitized periapical, bitewing, and panoramic radiographs and compared among them. From a total of 1484 records, 39 sets of radiographs that fulfilled the inclusion criteria of the study sample were selected. The measurements were grouped according to the intensity of bone loss. Statistically significant difference was found in the averages of the measurements assessed in radiographs with absence of bone loss between conventional panoramic and periapical radiographs, between digitized panoramic and periapical radiographs and between digitized bitewing and panoramic radiographs. By analyzing the results of this work and considering the research protocol used, one can conclude that small losses in height of alveolar bone crest observed in panoramic radiographs should be cautiously evaluated, as they may be overestimated. PMID:21991470

  5. Are panoramic radiographs reliable to diagnose mild alveolar bone resorption?

    PubMed

    Semenoff, Larissa; Semenoff, Tereza Aparecida Delle; Pedro, Fabio Luiz Miranda; Volpato, Evaristo Ricci; Machado, Maria Aparecida de Andrade Moreira; Borges, Alvaro Henrique; Semenoff-Segundo, Alex

    2011-01-01

    It is extremely important to assess variations between the most used radiographs in dental practice, since minimum distortion on obtained images may change diagnosis, treatment plan, and prognosis for the patient. For this, the distance between the enamel-cementum junction and the alveolar bone crest was measured on conventional and digitized periapical, bitewing, and panoramic radiographs and compared among them. From a total of 1484 records, 39 sets of radiographs that fulfilled the inclusion criteria of the study sample were selected. The measurements were grouped according to the intensity of bone loss. Statistically significant difference was found in the averages of the measurements assessed in radiographs with absence of bone loss between conventional panoramic and periapical radiographs, between digitized panoramic and periapical radiographs and between digitized bitewing and panoramic radiographs. By analyzing the results of this work and considering the research protocol used, one can conclude that small losses in height of alveolar bone crest observed in panoramic radiographs should be cautiously evaluated, as they may be overestimated.

  6. The one-leg standing radiograph

    PubMed Central

    Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis was evaluated using the joint space width and Kellgren-Lawrence (KL) radiographic classification. The t-test was used for statistical analysis. Results The mean medial joint space width found in the one-leg and in the both-legs standing view were measured at 1.8 mm and 2.4 mm, respectively (p < 0.001, 95% CI 0.5 to 0.7). 33%, 47.4% and 23.1% of the knees diagnosed with a KL grade of I, II and III in the both-legs standing views were changed to KL grade II, III and IV in the one-leg standing views, respectively. No changes for KL IV osteoarthritis diagnoses have been found between both- and one-leg standing views. Conclusions One-leg standing radiographs better represent joint space width than both-legs standing radiographs. 32% of both-legs standing radiographs have changed the KL grading to a more severe grade than that in the one-leg standing radiographs. Cite this article: P. Pinsornsak, K. Naratrikun, S. Kanitnate, T. Sangkomkamhang. The one-leg standing radiograph: An improved technique to evaluate the severity of knee osteoarthritis. Bone Joint Res 2016;5:436–441. DOI: 10.1302/2046-3758.59.BJR-2016-0049.R1. PMID:27683299

  7. A review of computer aided interpretation technology for the evaluation of radiographs of aluminum welds

    NASA Technical Reports Server (NTRS)

    Lloyd, J. F., Sr.

    1987-01-01

    Industrial radiography is a well established, reliable means of providing nondestructive structural integrity information. The majority of industrial radiographs are interpreted by trained human eyes using transmitted light and various visual aids. Hundreds of miles of radiographic information are evaluated, documented and archived annually. In many instances, there are serious considerations in terms of interpreter fatigue, subjectivity and limited archival space. Quite often it is difficult to quickly retrieve radiographic information for further analysis or investigation. Methods of improving the quality and efficiency of the radiographic process are being explored, developed and incorporated whenever feasible. High resolution cameras, digital image processing, and mass digital data storage offer interesting possibilities for improving the industrial radiographic process. A review is presented of computer aided radiographic interpretation technology in terms of how it could be used to enhance the radiographic interpretation process in evaluating radiographs of aluminum welds.

  8. 2D discrete Fourier transform on sliding windows.

    PubMed

    Park, Chun-Su

    2015-03-01

    Discrete Fourier transform (DFT) is the most widely used method for determining the frequency spectra of digital signals. In this paper, a 2D sliding DFT (2D SDFT) algorithm is proposed for fast implementation of the DFT on 2D sliding windows. The proposed 2D SDFT algorithm directly computes the DFT bins of the current window using the precalculated bins of the previous window. Since the proposed algorithm is designed to accelerate the sliding transform process of a 2D input signal, it can be directly applied to computer vision and image processing applications. The theoretical analysis shows that the computational requirement of the proposed 2D SDFT algorithm is the lowest among existing 2D DFT algorithms. Moreover, the output of the 2D SDFT is mathematically equivalent to that of the traditional DFT at all pixel positions.

  9. Practical guidelines for radiographers to improve computed radiography image quality.

    PubMed

    Pongnapang, N

    2005-10-01

    Computed Radiography (CR) has become a major digital imaging modality in a modern radiological department. CR system changes workflow from the conventional way of using film/screen by employing photostimulable phosphor plate technology. This results in the changing perspectives of technical, artefacts and quality control issues in radiology departments. Guidelines for better image quality in digital medical enterprise include professional guidelines for users and the quality control programme specifically designed to serve the best quality of clinical images. Radiographers who understand technological shift of the CR from conventional method can employ optimization of CR images. Proper anatomic collimation and exposure techniques for each radiographic projection are crucial steps in producing quality digital images. Matching image processing with specific anatomy is also important factor that radiographers should realise. Successful shift from conventional to fully digitised radiology department requires skilful radiographers who utilise the technology and a successful quality control program from teamwork in the department.

  10. Analysis of physiological impact while reading stereoscopic radiographs

    NASA Astrophysics Data System (ADS)

    Unno, Yasuko Y.; Tajima, Takashi; Kuwabara, Takao; Hasegawa, Akira; Natsui, Nobutaka; Ishikawa, Kazuo; Hatada, Toyohiko

    2011-03-01

    A stereoscopic viewing technology is expected to improve diagnostic performance in terms of reading efficiency by adding one more dimension to the conventional 2D images. Although a stereoscopic technology has been applied to many different field including TV, movies and medical applications, physiological fatigue through reading stereoscopic radiographs has been concerned although no established physiological fatigue data have been provided. In this study, we measured the α-amylase concentration in saliva, heart rates and normalized tissue hemoglobin index (nTHI) in blood of frontal area to estimate physiological fatigue through reading both stereoscopic radiographs and the conventional 2D radiographs. In addition, subjective assessments were also performed. As a result, the pupil contraction occurred just after the reading of the stereoscopic images, but the subjective assessments regarding visual fatigue were nearly identical for the reading the conventional 2D and stereoscopic radiographs. The α-amylase concentration and the nTHI continued to decline while examinees read both 2D and stereoscopic images, which reflected the result of subjective assessment that almost half of the examinees reported to feel sleepy after reading. The subjective assessments regarding brain fatigue showed that there were little differences between 2D and stereoscopic reading. In summary, this study shows that the physiological fatigue caused by stereoscopic reading is equivalent to the conventional 2D reading including ocular fatigue and burden imposed on brain.

  11. Reduction of a grid moire pattern by integrating a carbon-interspaced high precision x-ray grid with a digital radiographic detector

    SciTech Connect

    Yoon, Jai-Woong; Park, Young-Guk; Park, Chun-Joo; Kim, Do-Il; Lee, Jin-Ho; Chung, Nag-Kun; Choe, Bo-Young; Suh, Tae-Suk; Lee, Hyoung-Koo

    2007-11-15

    The stationary grid commonly used with a digital x-ray detector causes a moire interference pattern due to the inadequate sampling of the grid shadows by the detector pixels. There are limitations with the previous methods used to remove the moire such as imperfect electromagnetic interference shielding and the loss of image information. A new method is proposed for removing the moire pattern by integrating a carbon-interspaced high precision x-ray grid with high grid line uniformity with the detector for frequency matching. The grid was aligned to the detector by translating and rotating the x-ray grid with respect to the detector using microcontrolled alignment mechanism. The gap between the grid and the detector surface was adjusted with micrometer precision to precisely match the projected grid line pitch to the detector pixel pitch. Considering the magnification of the grid shadows on the detector plane, the grids were manufactured such that the grid line frequency was slightly higher than the detector sampling frequency. This study examined the factors that affect the moire pattern, particularly the line frequency and displacement. The frequency of the moire pattern was found to be sensitive to the angular displacement of the grid with respect to the detector while the horizontal translation alters the phase but not the moire frequency. The frequency of the moire pattern also decreased with decreasing difference in frequency between the grid and the detector, and a moire-free image was produced after complete matching for a given source to detector distance. The image quality factors including the contrast, signal-to-noise ratio and uniformity in the images with and without the moire pattern were investigated.

  12. Reduction of a grid moiré pattern by integrating a carbon-interspaced high precision x-ray grid with a digital radiographic detector.

    PubMed

    Yoon, Jai-Woong; Park, Young-Guk; Park, Chun-Joo; Kim, Do-Il; Lee, Jin-Ho; Chung, Nag-Kun; Choe, Bo-Young; Suh, Tae-Suk; Lee, Hyoung-Koo

    2007-11-01

    The stationary grid commonly used with a digital x-ray detector causes a moiré interference pattern due to the inadequate sampling of the grid shadows by the detector pixels. There are limitations with the previous methods used to remove the moiré such as imperfect electromagnetic interference shielding and the loss of image information. A new method is proposed for removing the moiré pattern by integrating a carbon-interspaced high precision x-ray grid with high grid line uniformity with the detector for frequency matching. The grid was aligned to the detector by translating and rotating the x-ray grid with respect to the detector using microcontrolled alignment mechanism. The gap between the grid and the detector surface was adjusted with micrometer precision to precisely match the projected grid line pitch to the detector pixel pitch. Considering the magnification of the grid shadows on the detector plane, the grids were manufactured such that the grid line frequency was slightly higher than the detector sampling frequency. This study examined the factors that affect the moiré pattern, particularly the line frequency and displacement. The frequency of the moiré pattern was found to be sensitive to the angular displacement of the grid with respect to the detector while the horizontal translation alters the phase but not the moiré frequency. The frequency of the moiré pattern also decreased with decreasing difference in frequency between the grid and the detector, and a moiré-free image was produced after complete matching for a given source to detector distance. The image quality factors including the contrast, signal-to-noise ratio and uniformity in the images with and without the moiré pattern were investigated.

  13. Weld radiograph enigmas

    NASA Technical Reports Server (NTRS)

    Jemian, Wartan A.

    1986-01-01

    Weld radiograph enigmas are features observed on X-ray radiographs of welds. Some of these features resemble indications of weld defects, although their origin is different. Since they are not understood, they are a source of concern. There is a need to identify their causes and especially to measure their effect on weld mechanical properties. A method is proposed whereby the enigmas can be evaluated and rated, in relation to the full spectrum of weld radiograph indications. Thie method involves a signature and a magnitude that can be used as a quantitive parameter. The signature is generated as the diference between the microdensitometer trace across the radiograph and the computed film intensity derived from a thickness scan along the corresponding region of the sample. The magnitude is the measured difference in intensity between the peak and base line values of the signature. The procedure is demonstated by comparing traces across radiographs of a weld sample before and after the introduction of a hole and by a system based on a MacIntosh mouse used for surface profiling.

  14. 2D/4D marker-free tumor tracking using 4D CBCT as the reference image.

    PubMed

    Wang, Mengjiao; Sharp, Gregory C; Rit, Simon; Delmon, Vivien; Wang, Guangzhi

    2014-05-07

    Tumor motion caused by respiration is an important issue in image-guided radiotherapy. A 2D/4D matching method between 4D volumes derived from cone beam computed tomography (CBCT) and 2D fluoroscopic images was implemented to track the tumor motion without the use of implanted markers. In this method, firstly, 3DCBCT and phase-rebinned 4DCBCT are reconstructed from cone beam acquisition. Secondly, 4DCBCT volumes and a streak-free 3DCBCT volume are combined to improve the image quality of the digitally reconstructed radiographs (DRRs). Finally, the 2D/4D matching problem is converted into a 2D/2D matching between incoming projections and DRR images from each phase of the 4DCBCT. The diaphragm is used as a target surrogate for matching instead of using the tumor position directly. This relies on the assumption that if a patient has the same breathing phase and diaphragm position as the reference 4DCBCT, then the tumor position is the same. From the matching results, the phase information, diaphragm position and tumor position at the time of each incoming projection acquisition can be derived. The accuracy of this method was verified using 16 candidate datasets, representing lung and liver applications and one-minute and two-minute acquisitions. The criteria for the eligibility of datasets were described: 11 eligible datasets were selected to verify the accuracy of diaphragm tracking, and one eligible dataset was chosen to verify the accuracy of tumor tracking. The diaphragm matching accuracy was 1.88 ± 1.35 mm in the isocenter plane and the 2D tumor tracking accuracy was 2.13 ± 1.26 mm in the isocenter plane. These features make this method feasible for real-time marker-free tumor motion tracking purposes.

  15. E-2D Advanced Hawkeye Aircraft (E-2D AHE)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-364 E-2D Advanced Hawkeye Aircraft (E-2D AHE) As of FY 2017 President’s Budget Defense...Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined

  16. Neutron radiographic viewing system

    NASA Technical Reports Server (NTRS)

    Leysath, W.; Brown, R. L.

    1972-01-01

    Neutron radiographic viewing system consisting of camera head and control processor is developed for use in nondestructive testing applications. Camera head consists of neutron-sensitive image intensifier system, power supply, and SEC vidicon camera head. Both systems, with their optics, are housed on test mount.

  17. Sex dimorphism in digital formulae of children.

    PubMed

    McIntyre, Matthew H; Cohn, Barbara A; Ellison, Peter T

    2006-01-01

    This paper presents results of a study designed to: 1) test for a sex difference in the relative lengths of the finger bones, including the second-to-fourth digit ratio (2D:4D), using left-hand radiographs taken in young children, 2) test whether sex differences can be explained by sex differences in fetal growth, and 3) test the serial stability of sex differences in relative digit lengths, including 2D:4D. Results are presented from 1,060 subjects of the California Child Health and Development Studies. One serial replication at about 9 years old is available from 271 subjects. Results indicate that relative digit lengths are sex-dimorphic in children (Manning et al. [1998] Hum. Reprod. 13:3000-3004, [2004] Early Hum. Dev. 80:161-168). Sex differences in digit length ratios are more pronounced within sibships, where shared family factors are controlled, and are not strongly associated with gross measures of fetal growth, like birth length or weight. Thus, sex differences in the fetal growth of the body are not implicated in sex differences in digital formulae, leaving open the possibility of more direct hormonal and/or genetic causation. However, 2D:4D declined between ages 6-8 in a longitudinal sample, and was a less consistent sex-dimorphic marker than 3D:4D across ethnic groups, suggesting that 3D:4D may be a better marker of perinatal sex differentiation. Prior conflicting findings about 2D:4D may be partly explained by variations in age and ethnicity of populations studied.

  18. Pulp size in molars: underestimation on radiographs.

    PubMed

    Chandler, N P; Ford, T R Pitt; Monteith, B D

    2004-08-01

    The aim was to determine whether radiographs provide a clinically useful indication of pulp size in diseased/restored human first molar teeth, and to investigate accessibility of pulp tissue for diagnostic testing using laser Doppler flowmetry (LDF). Extracted teeth of known age were collected. Restorative materials were removed and teeth with evidence of pulp exposures excluded. Fifty-six teeth were radiographed from buccal and mesial aspects, and then their crowns were sectioned axiobuccolingually and photographed. Images were digitally scanned and measurements made of the total pulp area (above a line across the most superior part of the pulpal floor) and the pulp area in the clinical crown (superior to a line between the amelocemental junctions). The pulp width at the cervix and the highest point of the pulp were also recorded. Data were analysed using Pearson correlations. Pulp areas within the clinical crowns were significantly larger than indicated by radiographs, by 23% in the case of the clinically attainable buccal view (P < 0.05). Pulps may be more accessible to flowmeter testing than they appear. Absence of pulp tissues in the crown was recorded in equal numbers of teeth on radiographs and sections, but with agreement for only one tooth. Sixteen per cent of the teeth had no pulp area in the clinical crown when sectioned, but might still be suitable for testing using LDF.

  19. DARHT Radiographic Grid Scale Correction

    SciTech Connect

    Warthen, Barry J.

    2015-02-13

    Recently it became apparent that the radiographic grid which has been used to calibrate the dimensional scale of DARHT radiographs was not centered at the location where the objects have been centered. This offset produced an error of 0.188% in the dimensional scaling of the radiographic images processed using the assumption that the grid and objects had the same center. This paper will show the derivation of the scaling correction, explain how new radiographs are being processed to account for the difference in location, and provide the details of how to correct radiographic image processed with the erroneous scale factor.

  20. Radiographic wear measurements in a cementless metal-backed modular cobalt-chromium acetabular component.

    PubMed

    Barrack, R L; Lavernia, C; Szuszczewicz, E S; Sawhney, J

    2001-10-01

    Linear polyethylene wear was measured radiographically and correlated with direct measurements of wear from 21 of 24 liners retrieved at revision. An optical comparator was used to assess linear wear using the shadowgraph technique. Postoperative and prerevision radiographs were reviewed to measure the amount of linear wear radiographically. Seven radiographic methods described in the literature were used: 5 were manual techniques, and 2 techniques used a computer-assisted digitizer. Linear regression analysis showed that there was a statistically significant correlation between the radiographic measurements compared with the direct measurement for 4 of the 5 manual techniques but only 1 of the 2 computerized techniques. Based on these results, radiographic wear measurements of cementless, modular components should be considered qualitative rather than quantitative. There is a significant difference in the measurements obtained among various published techniques. The addition of computer digitization to enhance manual methodology does not improve accuracy.

  1. New generation transistor technologies enabled by 2D crystals

    NASA Astrophysics Data System (ADS)

    Jena, D.

    2013-05-01

    The discovery of graphene opened the door to 2D crystal materials. The lack of a bandgap in 2D graphene makes it unsuitable for electronic switching transistors in the conventional field-effect sense, though possible techniques exploiting the unique bandstructure and nanostructures are being explored. The transition metal dichalcogenides have 2D crystal semiconductors, which are well-suited for electronic switching. We experimentally demonstrate field effect transistors with current saturation and carrier inversion made from layered 2D crystal semiconductors such as MoS2, WS2, and the related family. We also evaluate the feasibility of such semiconducting 2D crystals for tunneling field effect transistors for low-power digital logic. The article summarizes the current state of new generation transistor technologies either proposed, or demonstrated, with a commentary on the challenges and prospects moving forward.

  2. Optoelectronics with 2D semiconductors

    NASA Astrophysics Data System (ADS)

    Mueller, Thomas

    2015-03-01

    Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.

  3. Automatic detection of scoliotic curves in posteroanterior radiographs.

    PubMed

    Duong, Luc; Cheriet, Farida; Labelle, Hubert

    2010-05-01

    Spinal deformities are diagnosed using posteroanterior (PA) radiographs. Automatic detection of the spine on conventional radiographs would be of interest to quantify curve severity, would help reduce observer variability and would allow large-scale retrospective studies on radiographic databases. The goal of this paper is to present a new method for automatic detection of spinal curves from a PA radiograph. A region of interest (ROI) is first extracted according to the 2-D shape variability of the spine obtained from a set of PA radiographs of scoliotic patients. This region includes 17 bounding boxes delimiting each vertebral level from T1 to L5. An adaptive filter combining shock with complex diffusion is used to individually restore the image of each vertebral level. Then, texture descriptors of small block elements are computed and submitted for training to support vector machines (SVM). Vertebral body's locations are thereby inferred for a particular vertebral level. The classifications of block elements for all 17 SVMs are identified in the image and a voting system is introduced to cumulate correctly predicted blocks. A spline curve is then fitted through the centers of the predicted vertebral regions and compared to a manual identification using a Student t-test. A clinical validation is performed using 100 radiographs of scoliotic patients (not used for training) and the detected spinal curve is found to be statistically similar (p < 0.05) in 93% of cases to the manually identified curve.

  4. Measurement accuracy and reliability of tooth length on conventional and CBCT reconstructed panoramic radiographs

    PubMed Central

    Flores-Mir, Carlos; Rosenblatt, Mark R; Major, Paul W.; Carey, Jason P.; Heo, Giseon

    2014-01-01

    INTRODUCTION: This in vivo study assessed accuracy and reliability of tooth length measurements obtained from conventional panoramic radiographs and CBCT panoramic reconstructions to that of a digital caliper (gold standard). METHODS: The sample consisted of subjects who had CBCT and conventional panoramic radiographic imaging and who required maxillary premolar extraction for routine orthodontic treatment. A total of 48 teeth extracted from 26 subjects were measured directly with digital calipers. Radiographic images were scanned and digitally measured in Dolphin 3D software. Accuracy of tooth length measurements made by CBCT panoramic reconstructions, conventional panoramic radiographs and digital caliper (gold standard) were compared to each other by repeated measures one-way ANOVA with Bonferroni correction and by single measures intraclass correlation coefficient. RESULTS: Repeated root length measures with digital calipers, panoramic radiographs and CBCT constructed panoramic-like images were all individually highly reliable. Compared to the caliper (gold standard), tooth measurements obtained from conventional panoramic radiographs were on average 6.3 mm (SD = 2.0 mm) longer, while tooth measurements from CBCT panoramic reconstructions were an average of 1.7 mm (SD = 1.2 mm) shorter. CONCLUSIONS: In comparison to actual tooth lengths, conventional panoramic radiographs were relatively inaccurate, overestimating the lengths by 29%, while CBCT panoramic reconstructions underestimated the lengths by 4%. PMID:25715716

  5. Highly crystalline 2D superconductors

    NASA Astrophysics Data System (ADS)

    Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro

    2016-12-01

    Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.

  6. Extensions of 2D gravity

    SciTech Connect

    Sevrin, A.

    1993-06-01

    After reviewing some aspects of gravity in two dimensions, I show that non-trivial embeddings of sl(2) in a semi-simple (super) Lie algebra give rise to a very large class of extensions of 2D gravity. The induced action is constructed as a gauged WZW model and an exact expression for the effective action is given.

  7. Validation of a novel technique for creating simulated radiographs using computed tomography datasets.

    PubMed

    Mendoza, Patricia; d'Anjou, Marc-André; Carmel, Eric N; Fournier, Eric; Mai, Wilfried; Alexander, Kate; Winter, Matthew D; Zwingenberger, Allison L; Thrall, Donald E; Theoret, Christine

    2014-01-01

    Understanding radiographic anatomy and the effects of varying patient and radiographic tube positioning on image quality can be a challenge for students. The purposes of this study were to develop and validate a novel technique for creating simulated radiographs using computed tomography (CT) datasets. A DICOM viewer (ORS Visual) plug-in was developed with the ability to move and deform cuboidal volumetric CT datasets, and to produce images simulating the effects of tube-patient-detector distance and angulation. Computed tomographic datasets were acquired from two dogs, one cat, and one horse. Simulated radiographs of different body parts (n = 9) were produced using different angles to mimic conventional projections, before actual digital radiographs were obtained using the same projections. These studies (n = 18) were then submitted to 10 board-certified radiologists who were asked to score visualization of anatomical landmarks, depiction of patient positioning, realism of distortion/magnification, and image quality. No significant differences between simulated and actual radiographs were found for anatomic structure visualization and patient positioning in the majority of body parts. For the assessment of radiographic realism, no significant differences were found between simulated and digital radiographs for canine pelvis, equine tarsus, and feline abdomen body parts. Overall, image quality and contrast resolution of simulated radiographs were considered satisfactory. Findings from the current study indicated that radiographs simulated using this new technique are comparable to actual digital radiographs. Further studies are needed to apply this technique in developing interactive tools for teaching radiographic anatomy and the effects of varying patient and tube positioning.

  8. Textbook of radiographic science

    SciTech Connect

    Bentley, H.B.

    1987-01-01

    This book has been written to provide an outline of scientific background of specialized radiologic procedures for candidates studying for the higher examination of the College of Radiographers (United Kingdom). The book contains nine chapters on various areas such as emergency/trauma; pediatrics; neurologic, angiographic, and urodynamic studies; and a final chapter on research. An index concludes the book. Information on historical and scientific procedural background, equipment, anatomic and pathologic correlates, and positioning of the patient is organized and presented. Scientific data are inserted in the text where appropriate. Metrizamide is given an extensive write-up as the contrast medium of choice for imaging of the spinal cord and is said to be ''less toxic than other forms of water-soluble contrast.''

  9. Dynamic Radiographic Imaging

    SciTech Connect

    Volkov, A.; Turley, D.; Veeser, L.; Lukyanov, N.; Yegorov, N.; Baker, S.A.; Mirenko, V.; Lewis, W.; Kuropatkin, Y.

    1999-06-01

    A radiographic system recently developed by American and Russian collaborators is designed to capture multiple images of a dynamic event lasting less than 10 microseconds. Various optical and electro-optical components were considered and their performance compared. The final system employed a solid crystal of lutetium oxyorthosilicate doped with cerium (LSO:Ce or LSO) for X-ray-to-light conversion with a coherent fiber optic bundle to relay the scintillator image to a streak camera with charge coupled device (CCD) readout. Resolution and sensitivity studies were carried out for this system on two different sources of X-rays: a 20 MeV microtron and a 70 MeV betatron.

  10. Computer-assisted diagnosis of chest radiographs for pneumoconioses

    NASA Astrophysics Data System (ADS)

    Soliz, Peter; Pattichis, Marios S.; Ramachandran, Janakiramanan; James, David S.

    2001-07-01

    A Computer-assisted Chest Radiograph Reader System (CARRS) was developed for the detection of pathological features in lungs presenting with pneumoconioses. CARRS applies novel techniques in automatic image segmentation, incorporates neural network-based pattern classification, and integrates these into a graphical user interface. The three aspects of CARRS are described: Chest radiograph digitization and display, rib and parenchyma characterization, and classification. The quantization of the chest radiograph film was optimized to maximize the information content of the digital images. Entropy was used as the benchmark for optimizing the quantization. From the rib-segmented images, regions of interest were selected by the pulmonologist. A feature vector composed of image characteristics such as entropy, textural statistics, etc. was calculated. A laterally primed adaptive resonance theory (LAPART) neural network was used as the classifier. LAPART classification accuracy averaged 86.8 %. Truth was determined by the two pulmonologists. The CARRS has demonstrated potential as a screening device. Today, 90% or more of the chest radiographs seen by the pulmonologist are normal. A computer-based system that can screen 50% or more of the chest radiographs represents a large savings in time and dollars.

  11. Radiographic Assessment for Back Pain

    MedlinePlus

    ... When Should I get an X-ray for Low Back Pain? Other Reasons for Having an X-ray What ... rays? What are Radiographic Assessments? Radiographic assessments for low back pain involve the use of X-rays to determine ...

  12. Radiographic dental implants recognition for geographic evaluation in human identification.

    PubMed

    Nuzzolese, E; Lusito, S; Solarino, B; Di Vella, G

    2008-06-01

    Dental implants for prosthetic rehabilitation with fixed crown or mobile partial/total dentures is a very common oral treatment among the population in Italy as elsewhere. There is a great number of implant systems of different designs. However, a catalogue of radiographic images and a description of the dental implants available in Italy would be useful in order to identify the manufacturer and the type of implant encountered in forensic casework. When an unidentified body is found with one or more implants in the jaws, and no dental record is available, clues gleaned from the type of implants used could give direction to the investigation. In this study Italian implant manufactures were contacted and asked to provide specimen implants. Digital radiographs were taken of all the implants donated at 0º, 30º, and 60º horizontal rotation, combined with -20º, -10º, 0º, +10º, and +20º vertical inclination relative to the radiographic beam and the X-ray sensor. A total of 15 images per implant were taken and examined to identify consistent, unique features that would aid in implant recognition. Only those observations made from radiographs between -10º and +10º vertical inclination would ever be used for definite identification of any implant. The information from this study should be considered a survey of the commercial distribution of dental implants in Italy through their digital radiographic images. It is also a starting point for a wider geographical evaluation of different manufacturers in other countries and continents. The radiographic images provided should help both the forensic odontologist and the prosthodontist to identify pre-existing implants which they may discover from their radiographic images.

  13. Oral tuberculosis: unusual radiographic findings.

    PubMed

    Sansare, K; Gupta, A; Khanna, V; Karjodkar, F

    2011-05-01

    Oral tuberculosis and its radiographic findings are not commonly encountered in an oral and maxillofacial radiology practice. Literature has occasional mention of the radiographic findings of oral tuberculosis, which are still ambiguous. When affected, it is manifested majorly in the oral mucosa and rarely in the jaw bones. Here, we report certain unusual radiographic findings of oral tuberculosis which have been rarely mentioned in the literature. Four illustrative cases describe bony resorption, condylar resorption, resorption of the inferior border of the mandible and rarefaction of the alveolar bone as radiographic findings of oral tuberculosis. Follow up of the first case demonstrated regeneration of the condylar head after anti-Kochs therapy was completed, a hitherto unreported phenomenon. The importance of including tuberculosis in the differential diagnosis of some of the unusual radiographic manifestations is emphasized.

  14. Comparison of radiograph-based texture analysis and bone mineral density with three-dimensional microarchitecture of trabecular bone

    SciTech Connect

    Ranjanomennahary, P.; Ghalila, S. Sevestre; Malouche, D; Marchadier, A.; Rachidi, M.; Benhamou, Cl.; Chappard, C.

    2011-01-15

    Purpose: Hip fracture is a serious health problem and textural methods are being developed to assess bone quality. The authors aimed to perform textural analysis at femur on high-resolution digital radiographs compared to three-dimensional (3D) microarchitecture comparatively to bone mineral density. Methods: Sixteen cadaveric femurs were imaged with an x-ray device using a C-MOS sensor. One 17 mm square region of interest (ROI) was selected in the femoral head (FH) and one in the great trochanter (GT). Two-dimensional (2D) textural features from the co-occurrence matrices were extracted. Site-matched measurements of bone mineral density were performed. Inside each ROI, a 16 mm diameter core was extracted. Apparent density (D{sub app}) and bone volume proportion (BV/TV{sub Arch}) were measured from a defatted bone core using Archimedes' principle. Microcomputed tomography images of the entire length of the core were obtained (Skyscan 1072) at 19.8 {mu}m of resolution and usual 3D morphometric parameters were computed on the binary volume after calibration from BV/TV{sub Arch}. Then, bone surface/bone volume, trabecular thickness, trabecular separation, and trabecular number were obtained by direct methods without model assumption and the structure model index was calculated. Results: In univariate analysis, the correlation coefficients between 2D textural features and 3D morphological parameters reached 0.83 at the FH and 0.79 at the GT. In multivariate canonical correlation analysis, coefficients of the first component reached 0.95 at the FH and 0.88 at the GT. Conclusions: Digital radiographs, widely available and economically viable, are an alternative method for evaluating bone microarchitectural structure.

  15. Comparative analysis of human and bovine teeth: radiographic density.

    PubMed

    Tanaka, Jefferson Luis Oshiro; Medici Filho, Edmundo; Salgado, José Antônio Pereira; Salgado, Miguel Angel Castillo; Moraes, Luiz Cesar de; Moraes, Mari Eli Leonelli de; Castilho, Julio Cezar de Melo

    2008-01-01

    Since bovine teeth have been used as substitutes for human teeth in in vitro dental studies, the aim of this study was to compare the radiographic density of bovine teeth with that of human teeth to evaluate their usability for radiographic studies. Thirty bovine and twenty human teeth were cut transversally in 1 millimeter-thick slices. The slices were X-rayed using a digital radiographic system and an intraoral X-ray machine at 65 kVp and 7 mA. The exposure time (0.08 s) and the target-sensor distance (40 cm) were standardized for all the radiographs. The radiographic densities of the enamel, coronal dentin and radicular dentin of each slice were obtained separately using the 'histogram' tool of Adobe Photoshop 7.0 software. The mean radiographic densities of the enamel, coronal dentin and radicular dentin were calculated by the arithmetic mean of the slices of each tooth. One-way ANOVA demonstrated statistically significant differences for the densities of bovine and human enamel (p < 0.05) and for bovine and human coronal dentin (p < 0.05). No statistically significant differences were found for the bovine and human radicular dentin (p > 0.05). Based on the results, the authors concluded that: a) the radiographic density of bovine enamel is significantly higher than that of human enamel; b) the radiodensity of bovine coronal dentin is statistically lower than the radiodensity of human coronal dentin; bovine radicular dentin is also less radiodense than human radicular dentin, although this difference was not statistically significant; c) bovine teeth should be used with care in radiographic in vitro studies.

  16. Digital radiography: an overview.

    PubMed

    Parks, Edwin T; Williamson, Gail F

    2002-11-15

    Since the discovery of X-rays in 1895, film has been the primary medium for capturing, displaying, and storing radiographic images. It is a technology that dental practitioners are the most familiar and comfortable with in terms of technique and interpretation. Digital radiography is the latest advancement in dental imaging and is slowly being adopted by the dental profession. Digital imaging incorporates computer technology in the capture, display, enhancement, and storage of direct radiographic images. Digital imaging offers some distinct advantages over film, but like any emerging technology, it presents new and different challenges for the practitioner to overcome. This article presents an overview of digital imaging including basic terminology and comparisons with film-based imaging. The principles of direct and indirect digital imaging modalities, intraoral and extraoral applications, image processing, and diagnostic efficacy will be discussed. In addition, the article will provide a list of questions dentists should consider prior to purchasing digital imaging systems for their practice.

  17. 2D:4D Ratio and its Implications in Medicine

    PubMed Central

    Jeevanandam, Saravanakumar

    2016-01-01

    Digit ratios, especially 2D:4D ratio, a potential proxy marker for prenatal androgen exposure shows sexual dimorphism. Existing literature and recent research show accumulating evidence on 2D:4D ratio showing correlations with various phenotypic traits in humans. Ratio of 2D:4D is found to correlate negatively to testosterone and positively to oestrogen in the foetus. Interestingly, it is constant since birth and not influenced by the adult hormone levels. Usually, males have lower ratios when compared to females. Prenatal androgen exposure and therefore, digit ratios have been reported to be associated with numerical competencies, spatial skills, handedness, cognitive abilities, academic performance, sperm counts, personalities and prevalence of obesity, migraine, eating disorders, depression, myopia, autism etc. The authors have attempted to write a brief account on the digit ratios and the dimorphism observed in various physiological, psychological and behavioural traits. Also, the authors have discussed the relevant molecular basics and the methods of measurement of digit ratios. PMID:28208851

  18. Registration of 2D C-Arm and 3D CT Images for a C-Arm Image-Assisted Navigation System for Spinal Surgery

    PubMed Central

    Chang, Chih-Ju; Lin, Geng-Li; Tse, Alex; Chu, Hong-Yu; Tseng, Ching-Shiow

    2015-01-01

    C-Arm image-assisted surgical navigation system has been broadly applied to spinal surgery. However, accurate path planning on the C-Arm AP-view image is difficult. This research studies 2D-3D image registration methods to obtain the optimum transformation matrix between C-Arm and CT image frames. Through the transformation matrix, the surgical path planned on preoperative CT images can be transformed and displayed on the C-Arm images for surgical guidance. The positions of surgical instruments will also be displayed on both CT and C-Arm in the real time. Five similarity measure methods of 2D-3D image registration including Normalized Cross-Correlation, Gradient Correlation, Pattern Intensity, Gradient Difference Correlation, and Mutual Information combined with three optimization methods including Powell's method, Downhill simplex algorithm, and genetic algorithm are applied to evaluate their performance in converge range, efficiency, and accuracy. Experimental results show that the combination of Normalized Cross-Correlation measure method with Downhill simplex algorithm obtains maximum correlation and similarity in C-Arm and Digital Reconstructed Radiograph (DRR) images. Spine saw bones are used in the experiment to evaluate 2D-3D image registration accuracy. The average error in displacement is 0.22 mm. The success rate is approximately 90% and average registration time takes 16 seconds. PMID:27018859

  19. Scanning radiographic apparatus

    SciTech Connect

    Albert, R.D.

    1980-04-01

    Visual display of dental, medical or other radiographic images is realized with an x-ray tube in which an electron beam is scanned through an x-y raster pattern on a broad anode plate, the scanning being synchronized with the x-y sweep signals of a cathode ray tube display and the intensity signal for the display being derived from a small x-ray detector which receives x-rays that have passed through the subject to be imaged. Positioning and support of the detector are provided for by disposing the detector in a probe which may be attached to the x-ray tube at any of a plurality of different locations and by providing a plurality of such probes of different configuration in order to change focal length, to accommodate to different detector placements relative to the subject, to enhance patient comfort and to enable production of both periapical images and wider angle pantomographic images. High image definition with reduced radiation dosage is provided for by a lead glass collimator situated between the x-ray tube and subject and having a large number of spaced-apart minute radiation transmissive passages convergent on the position of the detector. Releasable mounting means enable changes of collimator in conjunction with changes of the probe to change focal length. A control circuit modifies the x-y sweep signals applied to the x-ray tube and modulates electron beam energy and current in order to correct for image distortions and other undesirable effects which can otherwise be present in a scanning x-ray system.

  20. Film holder for radiographing tubing

    DOEpatents

    Davis, Earl V.; Foster, Billy E.

    1976-01-01

    A film cassette is provided which may be easily placed about tubing or piping and readily held in place while radiographic inspection is performed. A pair of precurved light-impervious semi-rigid plastic sheets, hinged at one edge, enclose sheet film together with any metallic foils or screens. Other edges are made light-tight with removable caps, and the entire unit is held securely about the object to be radiographed with a releasable fastener such as a strip of Velcro.

  1. Radiographic findings in liveborn triploidy.

    PubMed

    Silverthorn, K G; Houston, C S; Newman, D E; Wood, B J

    1989-01-01

    The detailed radiographic features of triploidy, a fatal congenital disorder with 69 chromosomes, have not previously been reported. Radiographs of ten liveborn infants with chromosomally confirmed triploidy showed six findings highly suggestive of this diagnosis: harlequin orbits, small anterior fontanelle, gracile ribs, diaphyseal overtubulation of long bones, upswept clavicles and antimongoloid pelvis. Sixteen other less specific findings showed many similarities to those found in trisomy 18.

  2. 2D quasiperiodic plasmonic crystals

    PubMed Central

    Bauer, Christina; Kobiela, Georg; Giessen, Harald

    2012-01-01

    Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871

  3. Valleytronics in 2D materials

    NASA Astrophysics Data System (ADS)

    Schaibley, John R.; Yu, Hongyi; Clark, Genevieve; Rivera, Pasqual; Ross, Jason S.; Seyler, Kyle L.; Yao, Wang; Xu, Xiaodong

    2016-11-01

    Semiconductor technology is currently based on the manipulation of electronic charge; however, electrons have additional degrees of freedom, such as spin and valley, that can be used to encode and process information. Over the past several decades, there has been significant progress in manipulating electron spin for semiconductor spintronic devices, motivated by potential spin-based information processing and storage applications. However, experimental progress towards manipulating the valley degree of freedom for potential valleytronic devices has been limited until very recently. We review the latest advances in valleytronics, which have largely been enabled by the isolation of 2D materials (such as graphene and semiconducting transition metal dichalcogenides) that host an easily accessible electronic valley degree of freedom, allowing for dynamic control.

  4. Unparticle example in 2D.

    PubMed

    Georgi, Howard; Kats, Yevgeny

    2008-09-26

    We discuss what can be learned about unparticle physics by studying simple quantum field theories in one space and one time dimension. We argue that the exactly soluble 2D theory of a massless fermion coupled to a massive vector boson, the Sommerfield model, is an interesting analog of a Banks-Zaks model, approaching a free theory at high energies and a scale-invariant theory with nontrivial anomalous dimensions at low energies. We construct a toy standard model coupling to the fermions in the Sommerfield model and study how the transition from unparticle behavior at low energies to free particle behavior at high energies manifests itself in interactions with the toy standard model particles.

  5. Efficient feature-based 2D/3D registration of transesophageal echocardiography to x-ray fluoroscopy for cardiac interventions

    NASA Astrophysics Data System (ADS)

    Hatt, Charles R.; Speidel, Michael A.; Raval, Amish N.

    2014-03-01

    We present a novel 2D/ 3D registration algorithm for fusion between transesophageal echocardiography (TEE) and X-ray fluoroscopy (XRF). The TEE probe is modeled as a subset of 3D gradient and intensity point features, which facilitates efficient 3D-to-2D perspective projection. A novel cost-function, based on a combination of intensity and edge features, evaluates the registration cost value without the need for time-consuming generation of digitally reconstructed radiographs (DRRs). Validation experiments were performed with simulations and phantom data. For simulations, in silica XRF images of a TEE probe were generated in a number of different pose configurations using a previously acquired CT image. Random misregistrations were applied and our method was used to recover the TEE probe pose and compare the result to the ground truth. Phantom experiments were performed by attaching fiducial markers externally to a TEE probe, imaging the probe with an interventional cardiac angiographic x-ray system, and comparing the pose estimated from the external markers to that estimated from the TEE probe using our algorithm. Simulations found a 3D target registration error of 1.08(1.92) mm for biplane (monoplane) geometries, while the phantom experiment found a 2D target registration error of 0.69mm. For phantom experiments, we demonstrated a monoplane tracking frame-rate of 1.38 fps. The proposed feature-based registration method is computationally efficient, resulting in near real-time, accurate image based registration between TEE and XRF.

  6. Comparing prediction models for radiographic exposures

    NASA Astrophysics Data System (ADS)

    Ching, W.; Robinson, J.; McEntee, M. F.

    2015-03-01

    During radiographic exposures the milliampere-seconds (mAs), kilovoltage peak (kVp) and source-to-image distance can be adjusted for variations in patient thicknesses. Several exposure adjustment systems have been developed to assist with this selection. This study compares the accuracy of four systems to predict the required mAs for pelvic radiographs taken on a direct digital radiography system (DDR). Sixty radiographs were obtained by adjusting mAs to compensate for varying combinations of source-to-image distance (SID), kVp and patient thicknesses. The 25% rule, the DuPont Bit System and the DigiBit system were compared to determine which of these three most accurately predicted the mAs required for an increase in patient thickness. Similarly, the 15% rule, the DuPont Bit System and the DigiBit system were compared for an increase in kVp. The exposure index (EI) was used as an indication of exposure to the DDR. For each exposure combination the mAs was adjusted until an EI of 1500+/-2% was achieved. The 25% rule was the most accurate at predicting the mAs required for an increase in patient thickness, with 53% of the mAs predictions correct. The DigiBit system was the most accurate at predicting mAs needed for changes in kVp, with 33% of predictions correct. This study demonstrated that the 25% rule and DigiBit system were the most accurate predictors of mAs required for an increase in patient thickness and kVp respectively. The DigiBit system worked well in both scenarios as it is a single exposure adjustment system that considers a variety of exposure factors.

  7. Quantum coherence selective 2D Raman–2D electronic spectroscopy

    PubMed Central

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-01-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational–vibrational, electronic–vibrational and electronic–electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment–protein complexes. PMID:28281541

  8. Quantum coherence selective 2D Raman-2D electronic spectroscopy

    NASA Astrophysics Data System (ADS)

    Spencer, Austin P.; Hutson, William O.; Harel, Elad

    2017-03-01

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  9. Quantum coherence selective 2D Raman-2D electronic spectroscopy.

    PubMed

    Spencer, Austin P; Hutson, William O; Harel, Elad

    2017-03-10

    Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.

  10. Perception-based reversible watermarking for 2D vector maps

    NASA Astrophysics Data System (ADS)

    Men, Chaoguang; Cao, Liujuan; Li, Xiang

    2010-07-01

    This paper presents an effective and reversible watermarking approach for digital copyright protection of 2D-vector maps. To ensure that the embedded watermark is insensitive for human perception, we only select the noise non-sensitive regions for watermark embedding by estimating vertex density within each polyline. To ensure the exact recovery of original 2D-vector map after watermark extraction, we introduce a new reversible watermarking scheme based on reversible high-frequency wavelet coefficients modification. Within the former-selected non-sensitive regions, our watermarking operates on the lower-order vertex coordinate decimals with integer wavelet transform. Such operation further reduces the visual distortion caused by watermark embedding. We have validated the effectiveness of our scheme on our real-world city river/building 2D-vector maps. We give extensive experimental comparisons with state-of-the-art methods, including embedding capability, invisibility, and robustness over watermark attacking.

  11. The future of digital imaging in dentistry.

    PubMed

    Miles, D A; Razzano, M R

    2000-04-01

    Digital radiographic imaging in dentistry has matured. All the reasons dentists have cited for keeping conventional, film-based systems have been refuted: cost, sensors, storage, and training are not issues. There are many reasons to switch to digital. This article outlines external factors that dentists may not have considered that will influence the way they conduct business in their offices related to radiographic imaging. The evidence points to the inevitable adoption of digital imaging systems.

  12. Accuracy and Reliability of Postoperative Radiographic Evaluation of First Metatarsal-Phalangeal Joint Arthrodesis.

    PubMed

    Pirozzi, Kelly M; Meyr, Andrew J

    2017-03-03

    The clinical value of routine postoperative radiographic evaluation after orthopedic procedures has recently been called into question. The objective of the present investigation was to evaluate the ability of foot and ankle surgeons to accurately and reliably assess postoperative radiographs after first metatarsal-phalangeal joint arthrodesis. Thirty sets of digital radiographs from 11 patients who had undergone first metatarsal-phalangeal joint arthrodesis were retrospectively evaluated by 5 podiatric physicians board-certified in foot surgery. The surgeons were asked to answer several questions, including whether the radiograph appeared to be >4 or <4 postoperative weeks; whether the radiograph appeared to be >8 or <8 postoperative weeks; their estimation of the postoperative week; and whether they would allow the patient to begin weightbearing based on the radiographic findings. With respect to whether the radiographs were >4 or <4 postoperative weeks, surgeons made accurate assessments 63.33% of the time (95 of 150; range 56.67% to 73.33%), with a kappa of 0.220. With respect to whether the radiographs were >8 or <8 postoperative weeks, surgeons made accurate assessments 60.0% of the time (90 of 150; range 53.33% to 70.0%), with a kappa of 0.203. With respect to the estimation of the postoperative week of the radiograph, surgeons accurately assessed the radiographs within a 4-week period 34.0% of the time (54 of 150; range 26.67% to 46.67%), with a kappa of 0.425. With respect to allowing the patient to bear weight according to the radiographic findings, the surgeons were in complete agreement 26.67% of the time (8 of 30), with a kappa of 0.251. These results provide evidence against the serial routine use of postoperative radiographs for the first metatarsal-phalangeal joint arthrodesis in the absence of a specific clinical indication.

  13. A benchmark concept for simulation in radiographic testing

    SciTech Connect

    Ewert, U.; Deresch, A.; Bellon, C.; Jaenisch, G.-R.

    2014-02-18

    The new standard ISO 17636–2:2013 “NDT of welds: Radiographic testing - Part 2: X- and gamma ray techniques with digital detectors” describes a complex procedure for film replacement by phosphor imaging plates and digital detector arrays. RT modeling software should consider these detector types, X-ray film, and the standard requirements for image quality. Practitioners expect the same visibility of image quality indicators (IQI) in the simulated radiographs as in the experimental exposures. The proposed benchmark test is based on the comparison of experimental radiographs taken at BAM with modeled ones of participants. The experimental setup and the determination of the equivalent penetrameter sensitivity (EPS) as described in the procedure of ASTM E 746 are used for quantitative evaluation of the achievable contrast sensitivity for step hole IQIs as considered in Annex B of ISO 17636–2. System classification data for Computed Radiography (CR) and film systems will be provided by BAM according to ISO 11699–1 for selected film systems and according to ASTM E 2446 for selected CR systems. The classification of films and digital detectors is based on the measurement of the dose response function, the basic spatial resolution (SR{sub b}) of the image, and the measured image noise, which depends on the detector efficiency, the quantum statistics, and the detector fixed pattern noise.

  14. Accurate positioning for head and neck cancer patients using 2D and 3D image guidance

    PubMed Central

    Kang, Hyejoo; Lovelock, Dale M.; Yorke, Ellen D.; Kriminiski, Sergey; Lee, Nancy; Amols, Howard I.

    2011-01-01

    Our goal is to determine an optimized image-guided setup by comparing setup errors determined by two-dimensional (2D) and three-dimensional (3D) image guidance for head and neck cancer (HNC) patients immobilized by customized thermoplastic masks. Nine patients received weekly imaging sessions, for a total of 54, throughout treatment. Patients were first set up by matching lasers to surface marks (initial) and then translationally corrected using manual registration of orthogonal kilovoltage (kV) radiographs with DRRs (2D-2D) on bony anatomy. A kV cone beam CT (kVCBCT) was acquired and manually registered to the simulation CT using only translations (3D-3D) on the same bony anatomy to determine further translational corrections. After treatment, a second set of kVCBCT was acquired to assess intrafractional motion. Averaged over all sessions, 2D-2D registration led to translational corrections from initial setup of 3.5 ± 2.2 (range 0–8) mm. The addition of 3D-3D registration resulted in only small incremental adjustment (0.8 ± 1.5 mm). We retrospectively calculated patient setup rotation errors using an automatic rigid-body algorithm with 6 degrees of freedom (DoF) on regions of interest (ROI) of in-field bony anatomy (mainly the C2 vertebral body). Small rotations were determined for most of the imaging sessions; however, occasionally rotations > 3° were observed. The calculated intrafractional motion with automatic registration was < 3.5 mm for eight patients, and < 2° for all patients. We conclude that daily manual 2D-2D registration on radiographs reduces positioning errors for mask-immobilized HNC patients in most cases, and is easily implemented. 3D-3D registration adds little improvement over 2D-2D registration without correcting rotational errors. We also conclude that thermoplastic masks are effective for patient immobilization. PMID:21330971

  15. Digit ratio in birds.

    PubMed

    Lombardo, Michael P; Thorpe, Patrick A; Brown, Barbara M; Sian, Katie

    2008-12-01

    The Homeobox (Hox) genes direct the development of tetrapod digits. The expression of Hox genes may be influenced by endogenous sex steroids during development. Manning (Digit ratio. New Brunswick, NJ: Rutgers University Press, 2002) predicted that the ratio between the lengths of digits 2 (2D) and 4 (4D) should be sexually dimorphic because prenatal exposure to estrogens and androgens positively influence the lengths of 2D and 4D, respectively. We measured digits and other morphological traits of birds from three orders (Passeriformes, house sparrow, Passer domesticus; tree swallow, Tachycineta bicolor; Pscittaciformes, budgerigar, Melopsittacus undulates; Galliformes, chicken, Gallus domesticus) to test this prediction. None were sexually dimorphic for 2D:4D and there were no associations between 2D:4D and other sexually dimorphic traits. When we pooled data from all four species after we averaged right and left side digits from each individual and z-transformed the resulting digit ratios, we found that males had significantly larger 2D:4D than did females. Tetrapods appear to be sexually dimorphic for 2D:4D with 2D:4D larger in males as in some birds and reptiles and 2D:4D smaller in males as in some mammals. The differences between the reptile and mammal lineages in the directionality of 2D:4D may be related to the differences between them in chromosomal sex determination. We suggest that (a) natural selection for a perching foot in the first birds may have overridden the effects of hormones on the development of digit ratio in this group of vertebrates and (b) caution be used in making inferences about prenatal exposure to hormones and digit ratio in birds.

  16. Acid corrosive esophagitis: radiographic findings.

    PubMed

    Muhletaler, C A; Gerlock, A J; de Soto, L; Halter, S A

    1980-06-01

    Thirty-nine esophagograms of 24 patients after ingestion of muriatic acid (27% HCI) in suicide attempts were reviewed. All esophagograms were obtained in the acute, subacute, and chronic phases. In the acute and subacute phases, the radiographic findings consisted of mucosal edema, submucosal edema or hemorrhage, ulcerations, sloughing of the mucosa, atony, and dilatation. Strictures of the esophagus were present in the chronic phase. These radiographic findings were not different from those found in alkaline corrosive esophagitis. The severity of the corrosive esophagitis is considered related to the concentration, amount, viscosity, and duration of contact between the caustic agent and the esophageal mucosa.

  17. Tonsillolith: a panoramic radiograph presentation.

    PubMed

    Babu B, Balaji; Tejasvi M L, Avinash; Avinash, C K Anulekha; B, Chittaranjan

    2013-10-01

    Tonsilloliths are calcifications within a tonsillar crypt, involve primarily the palatine tonsil caused by dystrophic calcification as a result of chronic inflammation. Tonsilloliths are very uncommon and are microscopic. Tonsillar concretions sometimes produce symptoms which include non-specific chronic halitosis, irritable cough, dysphagia, otalgia and foreign body-like sensation or foul taste. Patients with tonsillolithiasis may also be asymptomatic, with their lesions being discovered incidentally on panoramic radiographs. This article presents an unusual case of multiple bilateral and asymptomatic tonsilloliths which were found during a routine panoramic radiographic examination.

  18. Optimization of key building blocks for a large-area radiographic and fluoroscopic dynamic digital x-ray detector based on a-Si:H/CsI:Tl flat panel technology

    NASA Astrophysics Data System (ADS)

    Ducourant, Thierry; Michel, Marc; Vieux, Gerard; Peppler, Tobias; Trochet, J. C.; Schulz, Reiner F.; Bastiaens, Raoul J. M.; Busse, Falko

    2000-04-01

    This paper introduces the key design optimizations which have been carried out recently in Trixell in order to prepare the future family of large area, combined static (Radiography) and dynamic (Fluoroscopy, Cardio...) digital X-ray detectors based on a-Si:H/CsI:Tl flat panel technology. These optimizations have been carried out on a 16' X 12' prototype that has been designed and built in a product-oriented way. We describe the detector technology and give some of its main characteristics, as well as some preliminary measurement results.The heart of the new prototype is a Cesium Iodide scintillating screen, directly evaporated onto a 2 K X 2.5 K pixel, array of amorphous silicon photodiodes and TFTs deposited on a glass substrate. The pixel pitch is 155 micrometer. The detective flat panel is connected to dedicated electronics which provides line addressing, low-noise column readout and multiplexing into a serial electrical signal. This signal is digitized over 14 bits to provide a direct digital image output, available for the host radiology system via an optical fiber. This type of detector (flat panel + electronics) is built into a light and thin (less than 100 mm) packaging which can be easily integrated in various x-ray equipment such as R&F tables, Angiography systems (incl. Cardiology), and mobile C-arm systems.

  19. NKG2D ligands as therapeutic targets

    PubMed Central

    Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.

    2013-01-01

    The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565

  20. Fast DRR generation for 2D to 3D registration on GPUs

    SciTech Connect

    Tornai, Gabor Janos; Cserey, Gyoergy

    2012-08-15

    Purpose: The generation of digitally reconstructed radiographs (DRRs) is the most time consuming step on the CPU in intensity based two-dimensional x-ray to three-dimensional (CT or 3D rotational x-ray) medical image registration, which has application in several image guided interventions. This work presents optimized DRR rendering on graphical processor units (GPUs) and compares performance achievable on four commercially available devices. Methods: A ray-cast based DRR rendering was implemented for a 512 Multiplication-Sign 512 Multiplication-Sign 72 CT volume. The block size parameter was optimized for four different GPUs for a region of interest (ROI) of 400 Multiplication-Sign 225 pixels with different sampling ratios (1.1%-9.1% and 100%). Performance was statistically evaluated and compared for the four GPUs. The method and the block size dependence were validated on the latest GPU for several parameter settings with a public gold standard dataset (512 Multiplication-Sign 512 Multiplication-Sign 825 CT) for registration purposes. Results: Depending on the GPU, the full ROI is rendered in 2.7-5.2 ms. If sampling ratio of 1.1%-9.1% is applied, execution time is in the range of 0.3-7.3 ms. On all GPUs, the mean of the execution time increased linearly with respect to the number of pixels if sampling was used. Conclusions: The presented results outperform other results from the literature. This indicates that automatic 2D to 3D registration, which typically requires a couple of hundred DRR renderings to converge, can be performed quasi on-line, in less than a second or depending on the application and hardware in less than a couple of seconds. Accordingly, a whole new field of applications is opened for image guided interventions, where the registration is continuously performed to match the real-time x-ray.

  1. Reference for radiographic film interpreters

    NASA Technical Reports Server (NTRS)

    Austin, D. L.

    1970-01-01

    Reference of X-ray film images provides examples of weld defects, film quality, stainless steel welded tubing, and acceptable weld conditions. A summary sheet details the discrepancies shown on the film strip. This reference aids in interpreting and evaluating radiographic film of weldments.

  2. Radiographic findings of Proteus Syndrome.

    PubMed

    Gandhi, Nishant Mukesh; Davalos, Eric A; Varma, Rajeev K

    2014-01-01

    The extremely rare Proteus Syndrome is a hamartomatous congenital syndrome with substantial variability between clinical patient presentations. The diagnostic criteria consist of a multitude of clinical findings including hemihypertrophy, macrodactyly, epidermal nevi, subcutaneous hamartomatous tumors, and bony abnormalities. These clinical findings correlate with striking radiographic findings.

  3. Radiographic findings of Proteus Syndrome

    PubMed Central

    Gandhi, Nishant Mukesh; Davalos, Eric A.; Varma, Rajeev K.

    2015-01-01

    The extremely rare Proteus Syndrome is a hamartomatous congenital syndrome with substantial variability between clinical patient presentations. The diagnostic criteria consist of a multitude of clinical findings including hemihypertrophy, macrodactyly, epidermal nevi, subcutaneous hamartomatous tumors, and bony abnormalities. These clinical findings correlate with striking radiographic findings. PMID:27186241

  4. Improved radiographic image amplifier panel

    NASA Technical Reports Server (NTRS)

    Brown, R. L., Sr.

    1968-01-01

    Layered image amplifier for radiographic /X ray and gamma ray/ applications, combines very high radiation sensitivity with fast image buildup and erasure capabilities by adding a layer of material that is both photoconductive and light-emitting to basic image amplifier and cascading this assembly with a modified Thorne panel.

  5. Chemical intensification of dental radiographs

    SciTech Connect

    Price, C.

    1983-04-01

    The potential applications of chemical intensification in dental radiography are explored. Three standard photographic intensifiers and three methods designed for radiographic use are evaluated. One of these methods is shown to be capable of reducing radiation dose to one half, without loss of diagnostic quality. Further work is necessary to achieve a system sufficiently practicable to deserve widespread use in routine clinical dental radiography.

  6. Continuous Representations of Digital Images.

    DTIC Science & Technology

    1985-10-01

    adjacency topology on a 2D digital image S is well represented by the standard Euclidean topology on F (S ) (resp. U (S )). The topological spaces F(S) and U...space R as primitive approximation of a 2D digital image S by con- tinuous topological spaces . This space F (S) is not new. In fact, it has always been

  7. Is there a relation between local bone quality as assessed on panoramic radiographs and alveolar bone level?

    PubMed

    Nackaerts, Olivia; Gijbels, Frieda; Sanna, Anna-Maria; Jacobs, Reinhilde

    2008-03-01

    The aim was to explore the relation between radiographic bone quality on panoramic radiographs and relative alveolar bone level. Digital panoramic radiographs of 94 female patients were analysed (mean age, 44.5; range, 35-74). Radiographic density of the alveolar bone in the premolar region was determined using Agfa Musica software. Alveolar bone level and bone quality index (BQI) were also assessed. Relationships between bone density and BQI on one hand and the relative loss of alveolar bone level on the other were assessed. Mandibular bone density and loss of alveolar bone level were weakly but significantly negatively correlated for the lower premolar area (r = -.27). The BQI did not show a statistically significant relation to alveolar bone level. Radiographic mandibular bone density on panoramic radiographs shows a weak but significant relation to alveolar bone level, with more periodontal breakdown for less dense alveolar bone.

  8. A Dental Radiograph Recognition System Using Phase-Only Correlation for Human Identification

    NASA Astrophysics Data System (ADS)

    Ito, Koichi; Nikaido, Akira; Aoki, Takafumi; Kosuge, Eiko; Kawamata, Ryota; Kashima, Isamu

    In mass disasters such as earthquakes, fire disasters, tsunami, and terrorism, dental records have been used for identifying victims due to their processing time and accuracy. The greater the number of victims, the more time the identification tasks require, since a manual comparison between the dental radiograph records is done by forensic experts. Addressing this problem, this paper presents an efficient dental radiograph recognition system using Phase-Only Correlation (POC) for human identification. The use of phase components in 2D (two-dimensional) discrete Fourier transforms of dental radiograph images makes possible to achieve highly robust image registration and recognition. Experimental evaluation using a set of dental radiographs indicates that the proposed system exhibits efficient recognition performance for low-quality images.

  9. The impact of lossless image compression to radiographs

    NASA Astrophysics Data System (ADS)

    Lehmann, Thomas M.; Abel, Jürgen; Weiss, Claudia

    2006-03-01

    The increasing number of digital imaging modalities results in data volumes of several Tera Bytes per year that must be transferred and archived in a common-sized hospital. Hence, data compression is an important issue for picture archiving and communication systems (PACS). The effect of lossy image compression is frequently analyzed with respect to images from a certain modality supporting a certain diagnosis. However, novel compression schemes have been developed recently allowing efficient but lossless compression. In this study, we compare the lossless compression schemes embedded in the tagged image file format (TIFF), graphics interchange format (GIF), and Joint Photographic Experts Group (JPEG 2000 II) with the Borrows-Wheeler compression algorithm (BWCA) with respect to image content and origin. Repeated measures ANOVA was based on 1.200 images in total. Statistically significant effects (p < 0,0001) of compression scheme, image content, and image origin were found. Best mean compression factor of 3.5 (2.272 bpp) is obtained applying BTW to secondarily digitized radiographs of the head, while the lowest factor of 1,05 (7.587 bpp) resulted from the TIFF packbits algorithm applied to pelvis images captured digitally. Over all, the BWCA is slightly but significantly more effective than JPEG 2000. Both compression schemes reduce the required bits per pixel (bpp) below 3. Also, secondarily digitized images are more compressible than the directly digital ones. Interestingly, JPEG outperforms BWCA for directly digital images regardless of image content, while BWCA performs better than JPEG on secondarily digitized radiographs. In conclusion, efficient lossless image compression schemes are available for PACS.

  10. Patient-based radiographic exposure factor selection: a systematic review

    SciTech Connect

    Ching, William; Robinson, John; McEntee, Mark

    2014-09-15

    Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system.

  11. Correlating the clinical assessment of impacted mandibular third molars with panoramic radiograph and intraoral periapical radiograph

    PubMed Central

    Priya, P. Vani; Nasyam, Fazil A.; Ramprasad, M.; Penumatsa, Narendra V.; Akifuddin, Syed; Sandeep

    2016-01-01

    Aims And Objectives: This study was conducted to compare the clinical assessment of impacted third molars of mandible with panaromic radiograph (OPG) and intraoral periapical radiograph (IOPA) and to assess the efficacy of IOPA and. Moreover, we corroborated the OPG and IOPA findings of impacted mandiblar third molar root apex to inferior alveolar canal. Materials and Methods: A total of 200 patients with pericoronitis were examined who were indicated for surgical extraction, among which 50 patients were selected for the study. All the patients underwent a radiographic survey with a digital OPG and IOPA of impacted mandibular third molars, along with clinical survey for anatomic relationship, type of impaction, space available, position in relation to second molar, number of roots, root curvature, and proximity of nerve canal. The data was subjected to statistical analysis. The Statistical Package for Social Sciences version 4.0.1 software was used for analyzing the collected data. Results: The study revealed that IOPA was more accurate in determining a majority of the factors affecting the third molar surgery, including relationship of the external oblique ridge (IOPA vs OPG = 96%:90%), anteroposterior relation with ramus (IOPA vs OPG = 70%:66%), vertical depth of impaction (IOPA vs OPG = 72%:68%), number of roots (P = 0.013), morphology of roots (IOPA vs OPG = 96%:90%); however, OPG was found to be accurate in evaluating the type of impaction (IOPA vs OPG = 88%:94%), canal relation, along with root of impacted molar (IOPA vs OPG = 74%:86%). Conclusion: To conclude, although IOPA has a marginal angle over OPG in assessing various parameters, only the number of roots have a greater accuracy (P < 0.0013) in IOPA than with OPG. However, the OPG is the better choice to be considered when the patient is associated with trismus. PMID:28217540

  12. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or both... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film. 892.1840 Section 892.1840...

  13. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or both... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film. 892.1840 Section 892.1840...

  14. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film. 892.1840 Section 892.1840 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or...

  15. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film. 892.1840 Section 892.1840 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or...

  16. 21 CFR 892.1840 - Radiographic film.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film. 892.1840 Section 892.1840 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1840 Radiographic film. (a) Identification. Radiographic film is a device that consists of a thin sheet of radiotransparent material coated on one or...

  17. Radiographic techniques for investigating cereal grains

    SciTech Connect

    Winkler, M.A.

    1981-10-01

    Radiographic examination of cereal grain can determine nondestructively the presence of internal structural damage and other defects, which can be correlated to associated problems such as disease and infestation. Radiographs of several representative grains demonstrate the capabilities of the radiographic technique to detect structural deviations in the grains.

  18. Robust initialization of 2D-3D image registration using the projection-slice theorem and phase correlation

    SciTech Connect

    Bom, M. J. van der; Bartels, L. W.; Gounis, M. J.; Homan, R.; Timmer, J.; Viergever, M. A.; Pluim, J. P. W.

    2010-04-15

    Purpose: The image registration literature comprises many methods for 2D-3D registration for which accuracy has been established in a variety of applications. However, clinical application is limited by a small capture range. Initial offsets outside the capture range of a registration method will not converge to a successful registration. Previously reported capture ranges, defined as the 95% success range, are in the order of 4-11 mm mean target registration error. In this article, a relatively computationally inexpensive and robust estimation method is proposed with the objective to enlarge the capture range. Methods: The method uses the projection-slice theorem in combination with phase correlation in order to estimate the transform parameters, which provides an initialization of the subsequent registration procedure. Results: The feasibility of the method was evaluated by experiments using digitally reconstructed radiographs generated from in vivo 3D-RX data. With these experiments it was shown that the projection-slice theorem provides successful estimates of the rotational transform parameters for perspective projections and in case of translational offsets. The method was further tested on ex vivo ovine x-ray data. In 95% of the cases, the method yielded successful estimates for initial mean target registration errors up to 19.5 mm. Finally, the method was evaluated as an initialization method for an intensity-based 2D-3D registration method. The uninitialized and initialized registration experiments had success rates of 28.8% and 68.6%, respectively. Conclusions: The authors have shown that the initialization method based on the projection-slice theorem and phase correlation yields adequate initializations for existing registration methods, thereby substantially enlarging the capture range of these methods.

  19. Development of welding defects identifier application on radiographic film using gray level co-occurrence matrix and backpropagation

    NASA Astrophysics Data System (ADS)

    Abidin, Zaenal; Anompa, Muhammad Angger; Muhtadan

    2013-09-01

    Development of Welding Defect Identifiers for application in Radiographic Film by using Gray Level Co-Occurrence Matrix and Back-Propagation. A research on the application development to interpret the welding defects in industrial radiographic films by using neural networks has been conducted. This research is aimed to produce an application that implement the digital image processing, feature extraction and pattern recognition using artificial neural networks. Digital image processing applied in the development is the technique of noise removal using median filter, contrast stretching and image sharpening by Laplacian filter. Method of Grey level co-occurrence matrix (GLCM) is applied to extract features from digital images radiographic films. Back-propagation artificial neural network method is used for defect classification and interpretation of welding defect in radiographic films. The result of this research is an application of back-propagation neural networks with classification results for 60 simulated data with 95% of classification successful rate.

  20. Quantitative 2D liquid-state NMR.

    PubMed

    Giraudeau, Patrick

    2014-06-01

    Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.

  1. Micro-structural Fluctuations in 2D Dusty Plasma Liquids

    SciTech Connect

    I Lin; Huang, Y.-H.; Teng, L.-W.

    2007-07-13

    We address structural fluctuations in a cold 2D dusty plasma liquid which is self-organized through the strong Coulomb coupling of the negatively charged micro-meter sized dust particles suspending in weakly ionized discharges. The 2D liquids consist of triangular type ordered domains surrounded by defect clusters, which can be reorganized through avalanche type hopping under the interplay of strong Coulomb coupling and thermal fluctuations. The spatio-temporal evolutions of the local bond-orientational order are directly tracked through digital optical microscopy. The power law scaling of the temporal persistence length of fluctuations is obtained for the cold liquid. The measurement of the conditional probability of the persistence lengths of the successive fluctuating cycles suggests certain types of the persistence length combinations are more preferred. The memory of persistence lasts a few fluctuating cycles.

  2. HADES, A Radiographic Simulation Code

    SciTech Connect

    Aufderheide, M.B.; Slone, D.M.; Schach von Wittenau, A.E.

    2000-08-18

    We describe features of the HADES radiographic simulation code. We begin with a discussion of why it is useful to simulate transmission radiography. The capabilities of HADES are described, followed by an application of HADES to a dynamic experiment recently performed at the Los Alamos Neutron Science Center. We describe quantitative comparisons between experimental data and HADES simulations using a copper step wedge. We conclude with a short discussion of future work planned for HADES.

  3. Non-Radiographic Axial Spondyloarthritis.

    PubMed

    Slobodin, Gleb; Eshed, Iris

    2015-12-01

    The term non-radiographic axial spondyloarthritis (nrAxSpA) was coined for patients who have a clinical picture of ankylosing spondylitis (AS) but do not exhibit radiographic sacroiliitis. The ASAS classification criteria for nrAxSpA, ensuring the recruitment of homogenous study cohorts, were accepted in 2009, although the respective diagnostic criteria for daily clinical practice have not yet been developed. The clinical diagnosis should be based on the composite of clinical symptoms and signs of the disease, HLA B27 status, and magnetic resonance imaging (MRI) of sacroiliac joints. Notably, a negative MRI or HLA B27 does not exclude the diagnosis in patients with a high clinical suspicion for nrAxSpA. The prevalence of nrAxSpA is similar to that of AS, but the former has a higher female preponderance. The rate of progression of nrAxSpA to the radiographic stage of disease (AS) ranges from 10% to 20% over 2 years. Current treatment strategies for nrAxSpA are the same as for AS and include non-steroidal anti-inflammatory drugs and inhibitors of tumor necrosis factor-alpha. While this review summarizes the current achievements in the field of nrAxSpA, further understanding of the epidemiology and natural history of the disease and, particularly, mechanisms of inflammation and subsequent new bone formation is essential for the development of new treatment strategies for nrAxSpA patients.

  4. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  5. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  6. The palmar metric: A novel radiographic assessment of the equine distal phalanx

    PubMed Central

    Burd, M.A.; Craig, J.J.; Craig, M.F.

    2014-01-01

    Digital radiographs are often used to subjectively assess the equine digit. Recently, quantitative and objective radiographic measurements have been reported that give new insight into the form and function of the equine digit. We investigated a radio-dense curvilinear profile along the distal phalanx on lateral radiographs we term the Palmar Curve (PC) that we believe provides a measurement of the concavity of the distal phalanx of the horse. A second quantitative measurement, the Palmar Metric (PM) was defined as the percent area under the PC. We correlated the PM and age from 544 radiographs of the distal phalanx from the left and right front feet of various breed horses of known age, and 278 radiographs of the front feet of Quarter Horses. The PM was negatively correlated with age and decreased at a rate of 0.28 % per year for horses of various breeds and 0.33 % per year for Quarter Horses. Therefore, veterinarians should be aware of age related change in the concave, parietal solar aspect of the distal phalanx in the horse. PMID:26623343

  7. Statement of Work Third Party Algorithm Development and Evaluation of Detection of Liquid Explosives in Dual-Energy Digital Radiographic/TIP Ready X-ray Images - Public Version

    SciTech Connect

    Nekoogar, F; Martz, Jr., H E

    2009-09-23

    The purpose of this statement of work is for third party collaborators to train, validate and have Lawrence Livermore National Security, LLC (LLNS) evaluate algorithms to detect liquid threats in digital radiography (DR)/TIP Ready X-ray (TRX) images that will be provided by LLNS through the Transportation and Security Administration (TSA). LLNS will provide a set of images with threat(s) to determine detection rates and non-threat images from airports to determine false alarm rates. A key including a bounding box showing the locations of the threats and non-threats will be provided for the images. It is expected that the Subcontractor shall use half of the images with their keys for training the algorithms and the other half shall be used for validation (third party evaluation) purposes. The Subcontractor shall not use the key to the second half of the data other than for the validation and reporting of the performance of its algorithm (not for training). The Subcontractor has 45 business days from the receipt of datasets and the Subcontract to: (1) Run their detection/classification algorithms on the data; (2) Deliver a final report describing their performance by generating Receiver Operator Characteristic (ROC) curves using their algorithm; and (3) Deliver a copy of the third party's executable software (already trained and validated by the datasets) to LLNL accompanied by a user manual. LLNS will evaluate the performance of the same algorithm on another separate set of data. LLNS evaluation of the Subcontractor's algorithm will be documented in a final report within 30 days of receiving the executable code. This report will be sent to TSA and the report may be disseminated to the Subcontract at TSA's discretion.

  8. Image data compression using a new floating-point digital signal processor.

    PubMed

    Siegel, E L; Templeton, A W; Hensley, K L; McFadden, M A; Baxter, K G; Murphey, M D; Cronin, P E; Gesell, R G; Dwyer, S J

    1991-08-01

    A new dual-ported, floating-point, digital signal processor has been evaluated for compressing 512 and 1,024 digital radiographic images using a full-frame, two-dimensional, discrete cosine transform (2D-DCT). The floating point digital signal processor operates at 49.5 million floating point instructions per second (MFLOPS). The level of compression can be changed by varying four parameters in the lossy compression algorithm. Throughput times were measured for both 2D-DCT compression and decompression. For a 1,024 x 1,024 x 10-bit image with a compression ratio of 316:1, the throughput was 75.73 seconds (compression plus decompression throughput). For a digital fluorography 1,024 x 1,024 x 8-bit image and a compression ratio of 26:1, the total throughput time was 63.23 seconds. For a computed tomography image of 512 x 512 x 12 bits and a compression ratio of 10:1 the throughput time was 19.65 seconds.

  9. Low 2D:4D Values Are Associated with Video Game Addiction

    PubMed Central

    Kornhuber, Johannes; Zenses, Eva-Maria; Lenz, Bernd; Stoessel, Christina; Bouna-Pyrrou, Polyxeni; Rehbein, Florian; Kliem, Sören; Mößle, Thomas

    2013-01-01

    Androgen-dependent signaling regulates the growth of the fingers on the human hand during embryogenesis. A higher androgen load results in lower 2D:4D (second digit to fourth digit) ratio values. Prenatal androgen exposure also impacts brain development. 2D:4D values are usually lower in males and are viewed as a proxy of male brain organization. Here, we quantified video gaming behavior in young males. We found lower mean 2D:4D values in subjects who were classified according to the CSAS-II as having at-risk/addicted behavior (n = 27) compared with individuals with unproblematic video gaming behavior (n = 27). Thus, prenatal androgen exposure and a hyper-male brain organization, as represented by low 2D:4D values, are associated with problematic video gaming behavior. These results may be used to improve the diagnosis, prediction, and prevention of video game addiction. PMID:24236143

  10. Low 2D:4D values are associated with video game addiction.

    PubMed

    Kornhuber, Johannes; Zenses, Eva-Maria; Lenz, Bernd; Stoessel, Christina; Bouna-Pyrrou, Polyxeni; Rehbein, Florian; Kliem, Sören; Mößle, Thomas

    2013-01-01

    Androgen-dependent signaling regulates the growth of the fingers on the human hand during embryogenesis. A higher androgen load results in lower 2D:4D (second digit to fourth digit) ratio values. Prenatal androgen exposure also impacts brain development. 2D:4D values are usually lower in males and are viewed as a proxy of male brain organization. Here, we quantified video gaming behavior in young males. We found lower mean 2D:4D values in subjects who were classified according to the CSAS-II as having at-risk/addicted behavior (n = 27) compared with individuals with unproblematic video gaming behavior (n = 27). Thus, prenatal androgen exposure and a hyper-male brain organization, as represented by low 2D:4D values, are associated with problematic video gaming behavior. These results may be used to improve the diagnosis, prediction, and prevention of video game addiction.

  11. Material identification with multichannel radiographs

    NASA Astrophysics Data System (ADS)

    Collins, Noelle; Jimenez, Edward S.; Thompson, Kyle R.

    2017-02-01

    This work aims to validate previous exploratory work done to characterize materials by matching their attenuation profiles using a multichannel radiograph given an initial energy spectrum. The experiment was performed in order to evaluate the effects of noise on the resulting attenuation profiles, which was ignored in simulation. Spectrum measurements have also been collected from various materials of interest. Additionally, a MATLAB optimization algorithm has been applied to these candidate spectrum measurements in order to extract an estimate of the attenuation profile. Being able to characterize materials through this nondestructive method has an extensive range of applications for a wide variety of fields, including quality assessment, industry, and national security.

  12. 3D/2D registration and segmentation of scoliotic vertebrae using statistical models.

    PubMed

    Benameur, Said; Mignotte, Max; Parent, Stefan; Labelle, Hubert; Skalli, Wafa; de Guise, Jacques

    2003-01-01

    We propose a new 3D/2D registration method for vertebrae of the scoliotic spine, using two conventional radiographic views (postero-anterior and lateral), and a priori global knowledge of the geometric structure of each vertebra. This geometric knowledge is efficiently captured by a statistical deformable template integrating a set of admissible deformations, expressed by the first modes of variation in Karhunen-Loeve expansion, of the pathological deformations observed on a representative scoliotic vertebra population. The proposed registration method consists of fitting the projections of this deformable template with the preliminary segmented contours of the corresponding vertebra on the two radiographic views. The 3D/2D registration problem is stated as the minimization of a cost function for each vertebra and solved with a gradient descent technique. Registration of the spine is then done vertebra by vertebra. The proposed method efficiently provides accurate 3D reconstruction of each scoliotic vertebra and, consequently, it also provides accurate knowledge of the 3D structure of the whole scoliotic spine. This registration method has been successfully tested on several biplanar radiographic images and validated on 57 scoliotic vertebrae. The validation results reported in this paper demonstrate that the proposed statistical scheme performs better than other conventional 3D reconstruction methods.

  13. Influence of Elevation Data Source on 2D Hydraulic Modelling

    NASA Astrophysics Data System (ADS)

    Bakuła, Krzysztof; StĘpnik, Mateusz; Kurczyński, Zdzisław

    2016-08-01

    The aim of this paper is to analyse the influence of the source of various elevation data on hydraulic modelling in open channels. In the research, digital terrain models from different datasets were evaluated and used in two-dimensional hydraulic models. The following aerial and satellite elevation data were used to create the representation of terrain-digital terrain model: airborne laser scanning, image matching, elevation data collected in the LPIS, EuroDEM, and ASTER GDEM. From the results of five 2D hydrodynamic models with different input elevation data, the maximum depth and flow velocity of water were derived and compared with the results of the most accurate ALS data. For such an analysis a statistical evaluation and differences between hydraulic modelling results were prepared. The presented research proved the importance of the quality of elevation data in hydraulic modelling and showed that only ALS and photogrammetric data can be the most reliable elevation data source in accurate 2D hydraulic modelling.

  14. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-01-01

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  15. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-12-31

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  16. Brittle damage models in DYNA2D

    SciTech Connect

    Faux, D.R.

    1997-09-01

    DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.

  17. 2D/3D switchable displays

    NASA Astrophysics Data System (ADS)

    Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.

    2006-02-01

    A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.

  18. 2-d Finite Element Code Postprocessor

    SciTech Connect

    Sanford, L. A.; Hallquist, J. O.

    1996-07-15

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  19. Chemical Approaches to 2D Materials.

    PubMed

    Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang

    2016-08-01

    Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology.

  20. Shear viscosity measurements in a 2D Yukawa liquid

    NASA Astrophysics Data System (ADS)

    Nosenko, Volodymyr

    2005-03-01

    Shear viscosity was measured for a 2D strongly-coupled Yukawa liquid. First, we formed a dilute monolayer suspension of microspheres in a partially-ionized rarefied gas, i.e., a dusty plasma. In the absence of manipulation, the suspension forms a 2D triangular lattice. We used a new in-situ method of applying a shear stress using the scattering forces applied by counter-propagating laser beams. The lattice melted and a shear flow formed. Using digital video microscopy for direct imaging and particle tracking, the microscopic dynamics of the shear flow are observed. Averaging the velocities of individual microspheres, a velocity flow profile was calculated. Using the Navier-Stokes equation with an additional frictional term to account for gas drag, we fit the velocity profile. The fit yielded the value of the shear viscosity. The kinematic viscosity of our particle suspension is of order 1 mm^2s-1, which is comparable to that for liquid water. We believe this is the first report of a rheological measurement in a 2D dusty plasma. This talk is based on V. Nosenko and J. Goree, PRL 93, 155004 (2004).

  1. 78 FR 53645 - Black Lung Benefits Act: Standards for Chest Radiographs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Office... final rule; withdrawal. SUMMARY: The Office of Workers' Compensation Programs (OWCP) published a direct... providing parallel standards for submission of digital radiographs in connection with claims filed under...

  2. Early radiographic changes in radiation bone injury

    SciTech Connect

    Fujita, M.; Tanimoto, K.; Wada, T.

    1986-06-01

    A chronologic series of periapical radiographs was evaluated for the purpose of detecting damage to bone and tooth-supporting tissues in a patient receiving radiation therapy for a basal cell carcinoma of the mandibular gingiva. Widening of the periodontal space was one of the early radiographic changes observed. It is suggested, from the sequence of radiographic changes, that radiation-induced changed in the circulatory system of the bone might be primarily responsible for the resulting changes.

  3. Observer POD for radiographic testing

    SciTech Connect

    Kanzler, Daniel E-mail: uwe.ewert@bam.de Ewert, Uwe E-mail: uwe.ewert@bam.de Müller, Christina E-mail: uwe.ewert@bam.de; Pitkänen, Jorma

    2015-03-31

    The radiographic testing (RT) is a non-destructive testing (NDT) method capable of finding volumetric and open planar defects depending on their orientation. The radiographic contrast is higher for larger penetrated length of the defect in a component. Even though, the detectability of defects does not only depend on the contrast, but also on the noise, the defect area and the geometry of the defect. The currently applied Probability of Detection (POD) approach uses a detection threshold that is only based on a constant noise level or on a constant contrast threshold. This does not reflect accurately the results of evaluations by human observers. A new approach is introduced, using the widely applied POD evaluation and additionally a detection threshold depending on the lateral area and shape of the indication. This work shows the process of calculating the POD curves with simulated data by the modeling software aRTist and with artificial reference data of different defect types, such as ASTM E 476 EPS plates, flat bottom holes and notches. Additional experiments with different operators confirm that the depth of a defect, the lateral area and shape of its indication contribute with different weight to the detectability of the defect if evaluated by human operators on monitors.

  4. Elbow clinical, ultrasonographic and radiographic study in patients with inflammatory joint diseases.

    PubMed

    Uson, Jacqueline; Miguélez-Sánchez, Roberto; de Los Riscos, Marina; Martínez-Blasco, María Jesús; Fernández-Espartero, Cruz; Villaverde-García, Virginia; Garrido, Jesús; Naredo, Esperanza

    2016-03-01

    The main objective of this cross-sectional observational study was to investigate the relationship between clinical, ultrasonographic (US) and radiographic elbow features in patients with inflammatory joint diseases (IJD). The secondary objective was to evaluate the association between regional clinical elbow diagnoses and imaging findings. Consecutive patients with IJD attending follow-up visits were assessed for elbow pain and standardized elbow examination. Seven regional clinical diagnoses were defined. Digital elbow radiographs were read for 9 abnormalities. A standardized elbow grayscale (GS) and power Doppler (PD) scan recorded 13 defined abnormalities. Analysis encompassed 361 clinical, 361 US and 340 radiographic elbow assessments from 181 patients. US and clinical assessments showed an overall higher agreement than radiographic and clinical assessments (68.8 vs 59.1%, p = 0.001). When structural US abnormalities were compared with radiographic findings, agreement was slightly higher than when comparing all US abnormalities with radiographic findings (77.3%, k 0.533 and 73.5%, k 0.492). Enthesophytes, the most common abnormalities, were not associated with clinical findings. Subclinical US-synovitis and US-enthesopathy were found, respectively, in 17.3 and 14.1% of the clinically normal elbows. Clinical elbow arthritis prevalence and bias-adjusted kappa (PABAK) agreement was good for radiographic fat pad sign, PD-synovitis and GS-synovitis. Clinical elbow enthesopathy PABAK agreement was moderate for GS-enthesopathy and radiographic calcifications. US showed acceptable agreement with clinical and radiographic assessments for detecting elbow inflammatory and structural abnormalities in patients with IJD. Because US detected more abnormalities than radiography and has the capability to detect more subclinical abnormalities, US may be potentially used as a first-line elbow diagnostic tool in this clinical setting.

  5. A new method for standardization of intraoral radiographs.

    PubMed

    Kiliç, A R; Efeoglu, E; Yilmaz, S

    1996-01-01

    Standardization of intraoral radiographs is necessary for longitudinal studies of alveolar bone changes. Several methods of standardizing have been developed. These all involve fixing the geometric relations between the object, the x-ray tube, and the film. This usually involves a film holder, mounted on an occlusal stent and connected to the x-ray tube via an adapter ring. There is, however, a problem of compatibility between various commercial adapter rings and film holder assemblies. In an attempt to overcome this problem, we developed a method of producing cast acrylic adapters by making a plaster cast from a silicon rubber impression of the x-ray tube. The adapter was devised so that radiographs could be taken of all four segments using the same standard commercially available film holder. A total of 128 radiographs were taken from 42 patients who underwent various types of periodontal surgery; 64 were taken preoperatively and 64 at 6 months postoperatively. These pairs were superposed and approximately 58% were found by qualitative inspection to show total matching of geometric outlines as well as maintenance of position on the film, and approximately 73% to show geometric matching. Changes in alveolar bone height were evaluated for 11 of these totally matching pairs by counting millimetric grids and by a computer-based indirect digital imaging system. These were found to correlate satisfactorily (r = .63).

  6. Automatic fusion of lateral cephalograms and digital volume tomography data—perspective for combining two modalities in the future

    PubMed Central

    Sauppe, S; Hourfar, J; Ludwig, B; Ulrici, J; Hell, E

    2015-01-01

    Objectives: This article investigates the combination of three-dimensional (3D) digital volume tomography data with two-dimensional (2D) cephalograms in dentomaxillofacial imaging. Methods: An automatic hierarchical method to adjust the geometrical relations of these two modalities is presented. The approach is tested on phantom and patient case data, where the feasibility, usability and potential possibilities of the presented innovative method are highlighted. Digitally reconstructed radiographs are computed by casting rays through the 3D volume to get a 2D projection of the volume to produce realistic simulated cephalograms. Different similarity measures are considered based on variations of statistical and deterministic optimization procedures. Stability, precision and accuracy of the method are investigated. Results: The presented algorithm demonstrates a reasonable solution of the corresponding 2D/3D registration problem. Exemplary results from phantom and patient case data are presented. Tooth movement could be determined, in contrast to the 2D lateral cephalogram, separated for each side in all three spatial directions. Conclusions: Achieved results are highlighted from a clinical point of view and demonstrate the clinical benefit in daily praxis. PMID:26119213

  7. Radiographical evaluation of ulcerative colitis

    PubMed Central

    Deepak, Parakkal; Bruining, David H.

    2014-01-01

    Radiographical modalities have become important diagnostic tools in cases of ulcerative colitis (UC). Imaging can be used non-invasively to determine the extent of involvement, severity of disease and to detect disease-related complications and extra-intestinal inflammatory bowel disease (IBD) manifestations. While abdominal X-rays and barium enemas still retain their relevance in specific clinical settings, the use of computed tomography enterography (CTE) or magnetic resonance enterography (MRE) are now used as first-line investigations to exclude active small bowel disease in IBD patients and can be utilized to detect active colonic inflammation. Additionally, CT colonography and MR colonography are emerging techniques with potential applications in UC. Ultrasonography, leukocyte scintigraphy and positron emission tomography are novel abdominal imaging modalities currently being explored for IBD interrogations. This plethora of radiological imaging options has become a vital component of UC assessments. PMID:24843072

  8. Calibration of radiographs by a reference metal ball affects preoperative selection of implant size.

    PubMed

    Schropp, Lars; Stavropoulos, Andreas; Gotfredsen, Erik; Wenzel, Ann

    2009-12-01

    The aim was to evaluate the impact of a reference ball for calibration of periapical and panoramic radiographs on preoperative selection of implant size for three implant systems. Presurgical digital radiographs (70 panoramic, 43 periapical) from 70 patients scheduled for single-tooth implant treatment, recorded with a metal ball placed in the edentulous area, were evaluated by three observers with the intent to select the appropriate implant size. Four reference marks corresponding to the margins of the metal ball were manually placed on the digital image by means of computer software. Additionally, an implant with proper dimensions for the respective site was outlined by manually placing four reference marks. The diameter of the metal ball and the unadjusted length and width of the implant were calculated. Implant size was adjusted according to a "standard" calibration method (SCM; magnification factor 1.25 in panoramic images and 1.05 in periapical images) and according to a reference ball calibration method (RCM; true magnification). Based on the unadjusted as well as the adjusted implant dimensions, the implant size was selected among those available in a given implant system. For periapical radiographs, when comparing SCM and RCM with unadjusted implant dimensions, implant size changed in 42% and 58%, respectively. When comparing SCM and RCM, implant size changed in 24%. For panoramic radiographs, comparing SCM and RCM changed implant size in 48%. The use of a reference metal ball for calibration of periapical and panoramic radiographs when selecting implant size during treatment planning might be advantageous.

  9. Orthotropic Piezoelectricity in 2D Nanocellulose

    NASA Astrophysics Data System (ADS)

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-10-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  10. Orthotropic Piezoelectricity in 2D Nanocellulose

    PubMed Central

    García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

    2016-01-01

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364

  11. Orthotropic Piezoelectricity in 2D Nanocellulose.

    PubMed

    García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

    2016-10-06

    The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V(-1), ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

  12. 2D microwave imaging reflectometer electronics

    SciTech Connect

    Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  13. Large Area Synthesis of 2D Materials

    NASA Astrophysics Data System (ADS)

    Vogel, Eric

    Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.

  14. 2D microwave imaging reflectometer electronics.

    PubMed

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  15. Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications.

    PubMed

    Fang, Yuan; Yushmanov, Pavel V; Furó, István

    2016-12-08

    Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. StartCopTextCopyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.

  16. A method to enhance 2D ion chamber array patient specific quality assurance for IMRT.

    PubMed

    Diaz Moreno, Rogelio Manuel; Venencia, Daniel; Garrigo, Edgardo; Pipman, Yakov

    2016-11-21

    Gamma index comparison has been established as a method for patient specific quality assurance in IMRT. Detector arrays can replace radiographic film systems to record 2D dose distributions and fulfill quality assurance requirements. These electronic devices present spatial resolution disadvantages with respect to films. This handicap can be partially overcome with a multiple acquisition sequence of adjacent 2D dose distributions. The detector spatial response influence can also be taken into account through the convolution of the calculated dose with the detector spatial response. A methodology that employs both approaches could allow for enhancements of the quality assurance procedure. 35 beams from different step and shoot IMRT plans were delivered on a phantom. 2D dose distributions were recorded with a PTW-729 ion chamber array for individual beams, following the multiple acquisition methodology. 2D dose distributions were also recorded on radiographic films. Measured dose distributions with films and with the PTW-729 array were processed with the software RITv5.2 for Gamma index comparison with calculated doses. Calculated dose was also convolved with the ion chamber 2D response and the Gamma index comparisons with the 2D dose distribution measured with the PTW-729 array was repeated. 3.7 ± 2.7% of points surpassed the accepted Gamma index when using radiographic films compared with calculated dose, with a minimum of 0.67 and a maximum of 13.27. With the PTW-729 multiple acquisition methodology compared with calculated dose, 4.1 ± 1.3% of points surpassed the accepted Gamma index, with a minimum of 1.44 and a maximum of 11.26. With the PTW- multiple acquisition methodology compared with convolved calculated dose, 2.7 ± 1.3% of points surpassed the accepted Gamma index, with a minimum of 0.42 and a maximum of 5.75. The results obtained in this work suggest that the comparison of merged adjacent dose distributions with convolved calculated dose

  17. Doping explosive materials for neutron radiographic enhancement.

    NASA Technical Reports Server (NTRS)

    Golliher, K. G.

    1971-01-01

    Discussion of studies relating to the selection of doping materials of high neutron absorption usable for enhancing the neutron radiographic imaging of explosive mixtures, without interfering with the proper chemical reaction of the explosives. The results of the studies show that gadolinium oxide is an excellent material for doping explosive mixtures to enhance the neutron radiographic image.

  18. Radiographic simulations and analysis for ASCI

    SciTech Connect

    Aufderheide, M.; Stone, D.; VonWittenau, A.

    1998-12-18

    In this paper, the authors describe their work on developing quantitatively accurate radiographic simulation and analysis tools for ASCI hydro codes. they have extended the ability of HADES, the code which simulates radiography through a mesh, to treat the complex meshes used in ASCI calculations. The ultimate goal is to allow direct comparison between experimental radiographs and full physics simulated radiographs of ASCI calculations. They describe the ray-tracing algorithm they have developed for fast, accurate simulation of dynamic radiographs with the meshes used in ALE3D, an LLNL ASCI code. Spectral effects and material compositions are included. In addition to the newness of the mesh types, the distributed nature of domain decomposed problems requires special treatment by the radiographic code. Because of the size of such problems, they have parallelized the radiographic simulation, in order to have quick turnaround time. presently, this is done using the domain decomposition from the hydro code. They demonstrate good parallel scaling as the size of the problem is increased. They show a comparison between an experimental radiograph of a high explosive detonation and a simulated radiograph of an ALE3D calculation. They conclude with a discussion of future work.

  19. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1910 Radiographic grid. (a) Identification....

  20. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1910 Radiographic grid. (a) Identification....

  1. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1910 Radiographic grid. (a) Identification....

  2. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1910 Radiographic grid. (a) Identification....

  3. 21 CFR 892.1910 - Radiographic grid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic grid. 892.1910 Section 892.1910 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1910 Radiographic grid. (a) Identification....

  4. Abdominal Plain Radiograph in Neonatal Intestinal Obstruction

    PubMed Central

    Prasad, G Raghavendra; Aziz, Amtul

    2017-01-01

    A comprehensive all-inclusive resource on plain radiograph in neonatal intestinal obstruction is presented. This is an attempt to develop a protocol and to regain expertise in evaluating a plain radiograph that most often yields more than enough clues to diagnose and to decide a plan of action. PMID:28083492

  5. 2D Distributed Sensing Via TDR

    DTIC Science & Technology

    2007-11-02

    plate VEGF CompositeSensor Experimental Setup Air 279 mm 61 78 VARTM profile: slope RTM profile: rectangle 22 1 Jul 2003© 2003 University of Delaware...2003 University of Delaware All rights reserved Vision: Non-contact 2D sensing ü VARTM setup constructed within TL can be sensed by its EM field: 2D...300.0 mm/ns. 1 2 1 Jul 2003© 2003 University of Delaware All rights reserved Model Validation “ RTM Flow” TDR Response to 139 mm VEGC

  6. Inkjet printing of 2D layered materials.

    PubMed

    Li, Jiantong; Lemme, Max C; Östling, Mikael

    2014-11-10

    Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials.

  7. DIGITAL RADIOGRAPHY OF SPECIAL NUCLEAR MATERIAL TEST PACKAGES

    SciTech Connect

    HOWARD, BOYD

    2006-02-02

    The purpose of this document is to provide a brief introduction to digital radiography (DR), and a description of the DR configuration that was used to radiographically image the Special Nuclear Material (SNM) Test Packages before and after function tests that have been conducted. Also included are (1) Attachment 1, a comprehensive index that describes at which phase of the certification process that digital radiographic images were acquired, (2) digital radiographic images of each of the six packages at various stages of the certification process, and (3) Attachment 2, imaging instructions, that specify the setup procedures and detailed parameters of the DR imaging methodology that were used.

  8. Automatic Masking for Robust 3D-2D Image Registration in Image-Guided Spine Surgery

    PubMed Central

    Ketcha, M. D.; De Silva, T.; Uneri, A.; Kleinszig, G.; Vogt, S.; Wolinsky, J.-P.; Siewerdsen, J. H.

    2016-01-01

    During spinal neurosurgery, patient-specific information, planning, and annotation such as vertebral labels can be mapped from preoperative 3D CT to intraoperative 2D radiographs via image-based 3D-2D registration. Such registration has been shown to provide a potentially valuable means of decision support in target localization as well as quality assurance of the surgical product. However, robust registration can be challenged by mismatch in image content between the preoperative CT and intraoperative radiographs, arising, for example, from anatomical deformation or the presence of surgical tools within the radiograph. In this work, we develop and evaluate methods for automatically mitigating the effect of content mismatch by leveraging the surgical planning data to assign greater weight to anatomical regions known to be reliable for registration and vital to the surgical task while removing problematic regions that are highly deformable or often occluded by surgical tools. We investigated two approaches to assigning variable weight (i.e., "masking") to image content and/or the similarity metric: (1) masking the preoperative 3D CT ("volumetric masking"); and (2) masking within the 2D similarity metric calculation ("projection masking"). The accuracy of registration was evaluated in terms of projection distance error (PDE) in 61 cases selected from an IRB-approved clinical study. The best performing of the masking techniques was found to reduce the rate of gross failure (PDE > 20 mm) from 11.48% to 5.57% in this challenging retrospective data set. These approaches provided robustness to content mismatch and eliminated distinct failure modes of registration. Such improvement was gained without additional workflow and has motivated incorporation of the masking methods within a system under development for prospective clinical studies. PMID:27335531

  9. Automatic Masking for Robust 3D-2D Image Registration in Image-Guided Spine Surgery.

    PubMed

    Ketcha, M D; De Silva, T; Uneri, A; Kleinszig, G; Vogt, S; Wolinsky, J-P; Siewerdsen, J H

    During spinal neurosurgery, patient-specific information, planning, and annotation such as vertebral labels can be mapped from preoperative 3D CT to intraoperative 2D radiographs via image-based 3D-2D registration. Such registration has been shown to provide a potentially valuable means of decision support in target localization as well as quality assurance of the surgical product. However, robust registration can be challenged by mismatch in image content between the preoperative CT and intraoperative radiographs, arising, for example, from anatomical deformation or the presence of surgical tools within the radiograph. In this work, we develop and evaluate methods for automatically mitigating the effect of content mismatch by leveraging the surgical planning data to assign greater weight to anatomical regions known to be reliable for registration and vital to the surgical task while removing problematic regions that are highly deformable or often occluded by surgical tools. We investigated two approaches to assigning variable weight (i.e., "masking") to image content and/or the similarity metric: (1) masking the preoperative 3D CT ("volumetric masking"); and (2) masking within the 2D similarity metric calculation ("projection masking"). The accuracy of registration was evaluated in terms of projection distance error (PDE) in 61 cases selected from an IRB-approved clinical study. The best performing of the masking techniques was found to reduce the rate of gross failure (PDE > 20 mm) from 11.48% to 5.57% in this challenging retrospective data set. These approaches provided robustness to content mismatch and eliminated distinct failure modes of registration. Such improvement was gained without additional workflow and has motivated incorporation of the masking methods within a system under development for prospective clinical studies.

  10. Automatic masking for robust 3D-2D image registration in image-guided spine surgery

    NASA Astrophysics Data System (ADS)

    Ketcha, M. D.; De Silva, T.; Uneri, A.; Kleinszig, G.; Vogt, S.; Wolinsky, J.-P.; Siewerdsen, J. H.

    2016-03-01

    During spinal neurosurgery, patient-specific information, planning, and annotation such as vertebral labels can be mapped from preoperative 3D CT to intraoperative 2D radiographs via image-based 3D-2D registration. Such registration has been shown to provide a potentially valuable means of decision support in target localization as well as quality assurance of the surgical product. However, robust registration can be challenged by mismatch in image content between the preoperative CT and intraoperative radiographs, arising, for example, from anatomical deformation or the presence of surgical tools within the radiograph. In this work, we develop and evaluate methods for automatically mitigating the effect of content mismatch by leveraging the surgical planning data to assign greater weight to anatomical regions known to be reliable for registration and vital to the surgical task while removing problematic regions that are highly deformable or often occluded by surgical tools. We investigated two approaches to assigning variable weight (i.e., "masking") to image content and/or the similarity metric: (1) masking the preoperative 3D CT ("volumetric masking"); and (2) masking within the 2D similarity metric calculation ("projection masking"). The accuracy of registration was evaluated in terms of projection distance error (PDE) in 61 cases selected from an IRB-approved clinical study. The best performing of the masking techniques was found to reduce the rate of gross failure (PDE > 20 mm) from 11.48% to 5.57% in this challenging retrospective data set. These approaches provided robustness to content mismatch and eliminated distinct failure modes of registration. Such improvement was gained without additional workflow and has motivated incorporation of the masking methods within a system under development for prospective clinical studies.

  11. Clinical performance of a prototype flat-panel digital detector for general radiography

    NASA Astrophysics Data System (ADS)

    Huda, Walter; Scalzetti, Ernest M.; Roskopf, Marsha L.; Geiger, Robert

    2001-08-01

    Digital radiographs obtained using a prototype Digital Radiography System (Stingray) were compared with those obtained using conventional screen-film. Forty adult volunteers each had two identical radiographs taken at the same level of radiation exposure, one using screen-film and the other the digital detector. Each digital image was processed by hand to ensure that the printed quality was optimal. Ten radiologists compared the diagnostic image quality of the digital images with the corresponding film radiographs using a seven point ranking scheme.

  12. Evaluation of trabecular bone patterns on dental radiographic images: influence of cortical bone

    NASA Astrophysics Data System (ADS)

    Amouriq, Yves; Evenou, Pierre; Arlicot, Aurore; Normand, Nicolas; Layrolle, Pierre; Weiss, Pierre; Guédon, Jean-Pierre

    2010-03-01

    For some authors trabecular bone is highly visible in intraoral radiographs. For other authors, the observed intrabony trabecular pattern is a representation of only the endosteal surface of cortical bone, not of intermedullary striae. The purpose of this preliminary study was to investigate the true anatomical structures that are visible in routine dental radiographs and classically denoted trabecular bone. This is a major point for bone texture analysis on radiographs. Computed radiography (CR) images of dog mandible section in molar region were compared with simulations calculated from high-resolution micro-CT volumes. Calculated simulations were obtained using the Mojette Transform. By digitally editing the CT volume, the simulations were separated into trabecular and cortical components into a region of interest. Different images were compared and correlated, some bone micro-architecture parameters calculated. A high correlation was found between computed radiographs and calculated simulations from micro-CT. The Mojette transform was successful to obtain high quality images. Cortical bone did not contribute to change in a major way simulated images. These first results imply that intrabony trabecular pattern observed on radiographs can not only be a representation of the cortical bone endosteal surface and that trabecular bone is highly visible in intraoral radiographs.

  13. Grading Osteoarthritic Changes of the Zygapophyseal Joints from Radiographs: A Reliability Study

    PubMed Central

    Little, Joshua W.; Grieve, Thomas J.; Cramer, Gregory D.; Rich, Jeffrey A.; Laptook, Evelyn E.; Stiefel, Joseph P.D.; Linaker, Kathleen

    2015-01-01

    Objective This study tested the reliability of a 5-point ordinal scale used to grade the severity of degenerative changes of zygapophyseal (Z) joints on standard radiographs. Methods Modifications were made to Kellgren’s grading system to improve agreement for grading the severity of osteoarthritic changes in lumbar Z joints. These included adding 1 grade of no degeneration, multiple radiographic views, and structured examiner training. Thirty packets of radiographic files were obtained, which included representation of all 5 grades including no degeneration (0) and Kellgren’s 4-point (1 to 4) joint degeneration classification criteria. Radiographs were digitized to create a radiographic atlas that was given to examiners for individual study and blinded evaluation sessions. Intra-rater and inter-rater agreement was determined by weighted kappa (κw) from the examination of 79 Z joints (25 packets). Results Using the modified scale and following training, examiners demonstrated a moderate to substantial level of inter-rater agreement (κw = 0.57, 0.60, and 0.68). Intra-rater agreement was moderate (κw = 0.42 and 0.54). Conclusions The modified Kellgren 5-point grading system provides acceptable intra- and inter-rater reliability when examiners are adequately trained. This grading system may be a useful method for future investigations assessing radiographic osteoarthritis of the Z joints. v PMID:26118786

  14. Principles of digital imaging.

    PubMed

    van der Stelt, P F

    2000-04-01

    Electronic sensors in diagnostic radiology are gradually replacing radiographic film. The advantages of this new technology include a lower radiation dose to the patient, an almost instantaneous availability of images without the need for chemical film processing, and the possibility of image enhancement and computer-aided feature extraction. Digital radiography is a promising technology, opening the door to new diagnostic procedures not available with traditional film-based imaging.

  15. Parallel Stitching of 2D Materials.

    PubMed

    Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing

    2016-03-23

    Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  16. The basics of 2D DIGE.

    PubMed

    Beckett, Phil

    2012-01-01

    The technique of two-dimensional (2D) gel electrophoresis is a powerful tool for separating complex mixtures of proteins, but since its inception in the mid 1970s, it acquired the stigma of being a very difficult application to master and was generally used to its best effect by experts. The introduction of commercially available immobilized pH gradients in the early 1990s provided enhanced reproducibility and easier protocols, leading to a pronounced increase in popularity of the technique. However gel-to-gel variation was still difficult to control without the use of technical replicates. In the mid 1990s (at the same time as the birth of "proteomics"), the concept of multiplexing fluorescently labeled proteins for 2D gel separation was realized by Jon Minden's group and has led to the ability to design experiments to virtually eliminate gel-to-gel variation, resulting in biological replicates being used for statistical analysis with the ability to detect very small changes in relative protein abundance. This technology is referred to as 2D difference gel electrophoresis (2D DIGE).

  17. Parallel stitching of 2D materials

    DOE PAGES

    Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...

    2016-01-27

    Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  18. 2D Transducer Array for High-Speed 3D Imaging System

    DTIC Science & Technology

    2007-11-02

    low voltage differential signaling ( LVDS ) interface and a peripheral component interconnect (PCI) bus. The maximum numbers of transmission and...32-channel analog to digital converter (ADC) was attached to the developed transducer array. LVDS 2D Array Front End D a t a A c q u i s i t i o

  19. Automatic localization of target vertebrae in spine surgery using fast CT-to-fluoroscopy (3D-2D) image registration

    NASA Astrophysics Data System (ADS)

    Otake, Y.; Schafer, S.; Stayman, J. W.; Zbijewski, W.; Kleinszig, G.; Graumann, R.; Khanna, A. J.; Siewerdsen, J. H.

    2012-02-01

    Localization of target vertebrae is an essential step in minimally invasive spine surgery, with conventional methods relying on "level counting" - i.e., manual counting of vertebrae under fluoroscopy starting from readily identifiable anatomy (e.g., the sacrum). The approach requires an undesirable level of radiation, time, and is prone to counting errors due to the similar appearance of vertebrae in projection images; wrong-level surgery occurs in 1 of every ~3000 cases. This paper proposes a method to automatically localize target vertebrae in x-ray projections using 3D-2D registration between preoperative CT (in which vertebrae are preoperatively labeled) and intraoperative fluoroscopy. The registration uses an intensity-based approach with a gradient-based similarity metric and the CMA-ES algorithm for optimization. Digitally reconstructed radiographs (DRRs) and a robust similarity metric are computed on GPU to accelerate the process. Evaluation in clinical CT data included 5,000 PA and LAT projections randomly perturbed to simulate human variability in setup of mobile intraoperative C-arm. The method demonstrated 100% success for PA view (projection error: 0.42mm) and 99.8% success for LAT view (projection error: 0.37mm). Initial implementation on GPU provided automatic target localization within about 3 sec, with further improvement underway via multi-GPU. The ability to automatically label vertebrae in fluoroscopy promises to streamline surgical workflow, improve patient safety, and reduce wrong-site surgeries, especially in large patients for whom manual methods are time consuming and error prone.

  20. Radiographic evaluation of mandibular ramus for gender estimation: Retrospective study

    PubMed Central

    Damera, Ajit; Mohanalakhsmi, Jonnala; Yellarthi, Pavan Kumar; Rezwana, Begum Mohammed

    2016-01-01

    Background and Aims: Gender estimation is a very important part of a study in the field of anthropology and forensic sciences. In the skeleton, gender estimation is the first step of the identification process as subsequent methods for age and stature estimation are sex-dependent. Skeletal components such as the pelvis and skull are investigated for gender estimation and the mandible is a practical element to analyze sexual dimorphism in fragmented bones. The aim of the present study is to measure, compare, and evaluate various measurements of the mandibular ramus, observed in digital orthopantomographs and also to assess the usefulness of the mandibular ramus as an aid in gender estimation. Materials and Methods: A radiographic retrospective study was conducted using 80 digital orthopantomographs to measure, compare, and evaluate the measurements of the mandibular ramus such as maximum ramus breadth, maximum ramus height, and coronoid heightusing Planmeca ProMax® digital machine to assess the usefulness of mandibular measurements in gender estimation. Results: Descriptive statistics of various measurements and associated univariate F ratios for both the sexes were determined. Four variables were significant predictor in classifying a given sample (P < 0.001). The F-statistic values indicated that measurements expressing the greatest sexual dimorphism were noticed in the maximum ramus height. Conclusion: Mandibular ramus can be considered as a valuable tool in gender estimation and the most reliable measurements were obtained of linear objects in the horizontal plane by digital panoramic imaging. PMID:27555722

  1. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  2. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  3. Automated Measurement of Fracture Callus in Radiographs Using Portable Software

    PubMed Central

    Porter, Stephen M.; Dailey, Hannah L.; Hollar, Katherine A.; Klein, Karina; Harty, James A.; Lujan, Trevor J.

    2016-01-01

    The development of software applications that assist the radiographic evaluation of fracture healing could advance clinical diagnosis and expedite the identification of effective treatment strategies. A radiographic feature regularly used as an outcome measure for basic and clinical fracture healing research is new bone growth, or fracture callus. In this study, we developed OrthoRead, a portable software application that uses image-processing algorithms to detect and measure fracture callus in plain radiographs. OrthoRead utilizes an optimal boundary tracking algorithm to semi-automatically segment the cortical surface, and a novel iterative thresholding selection algorithm to then automatically segment the fracture callus. The software was validated in three steps. First, algorithm accuracy and sensitivity were analyzed using surrogate models with known callus size. Second, the callus area of distal femur fractures measured using OrthoRead was compared to callus area manually outlined by orthopaedic surgeons. Third, the callus area of ovine tibial fractures was measured using OrthoRead and compared to callus volume measured from micro-CT. The software had less than a 5% error in measuring surrogate callus, and was insensitive to changes in image resolution, image rotation, and the size of the analyzed region of interest. Strong positive correlations existed between OrthoRead and clinicians (R2 = 0.98), and between 2D callus area and 3D callus volume (R2 = 0.70). The average run time for OrthoRead was 3 s when using a 2.7 GHz processor. By being accurate, fast, and robust, OrthoRead can support prospective and retrospective clinical studies investigating implant efficacy, and can assist research on fracture healing mechanobiology. PMID:26714245

  4. Effects of x-ray and CT image enhancements on the robustness and accuracy of a rigid 3D/2D image registration.

    PubMed

    Kim, Jinkoo; Yin, Fang-Fang; Zhao, Yang; Kim, Jae Ho

    2005-04-01

    A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration.

  5. Kinematic analysis of healthy hips during weight-bearing activities by 3D-to-2D model-to-image registration technique.

    PubMed

    Hara, Daisuke; Nakashima, Yasuharu; Hamai, Satoshi; Higaki, Hidehiko; Ikebe, Satoru; Shimoto, Takeshi; Hirata, Masanobu; Kanazawa, Masayuki; Kohno, Yusuke; Iwamoto, Yukihide

    2014-01-01

    Dynamic hip kinematics during weight-bearing activities were analyzed for six healthy subjects. Continuous X-ray images of gait, chair-rising, squatting, and twisting were taken using a flat panel X-ray detector. Digitally reconstructed radiographic images were used for 3D-to-2D model-to-image registration technique. The root-mean-square errors associated with tracking the pelvis and femur were less than 0.3 mm and 0.3° for translations and rotations. For gait, chair-rising, and squatting, the maximum hip flexion angles averaged 29.6°, 81.3°, and 102.4°, respectively. The pelvis was tilted anteriorly around 4.4° on average during full gait cycle. For chair-rising and squatting, the maximum absolute value of anterior/posterior pelvic tilt averaged 12.4°/11.7° and 10.7°/10.8°, respectively. Hip flexion peaked on the way of movement due to further anterior pelvic tilt during both chair-rising and squatting. For twisting, the maximum absolute value of hip internal/external rotation averaged 29.2°/30.7°. This study revealed activity dependent kinematics of healthy hip joints with coordinated pelvic and femoral dynamic movements. Kinematics' data during activities of daily living may provide important insight as to the evaluating kinematics of pathological and reconstructed hips.

  6. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet... for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  7. 21 CFR 892.1960 - Radiographic intensifying screen.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (a) Identification. A radiographic intensifying screen is a device that is a thin radiolucent sheet... for medical purposes to expose radiographic film. (b) Classification. Class I (general controls)....

  8. Interactive 2D to 3D stereoscopic image synthesis

    NASA Astrophysics Data System (ADS)

    Feldman, Mark H.; Lipton, Lenny

    2005-03-01

    Advances in stereoscopic display technologies, graphic card devices, and digital imaging algorithms have opened up new possibilities in synthesizing stereoscopic images. The power of today"s DirectX/OpenGL optimized graphics cards together with adapting new and creative imaging tools found in software products such as Adobe Photoshop, provide a powerful environment for converting planar drawings and photographs into stereoscopic images. The basis for such a creative process is the focus of this paper. This article presents a novel technique, which uses advanced imaging features and custom Windows-based software that utilizes the Direct X 9 API to provide the user with an interactive stereo image synthesizer. By creating an accurate and interactive world scene with moveable and flexible depth map altered textured surfaces, perspective stereoscopic cameras with both visible frustums and zero parallax planes, a user can precisely model a virtual three-dimensional representation of a real-world scene. Current versions of Adobe Photoshop provide a creative user with a rich assortment of tools needed to highlight elements of a 2D image, simulate hidden areas, and creatively shape them for a 3D scene representation. The technique described has been implemented as a Photoshop plug-in and thus allows for a seamless transition of these 2D image elements into 3D surfaces, which are subsequently rendered to create stereoscopic views.

  9. Unusual radiographic appearance of adamantinoma.

    PubMed

    Cappuccio, Michele; Montalti, Maurizio; Bosco, Giuseppe; Gasbarrini, Alessandro; Boriani, Stefano

    2009-12-01

    Adamantinoma is a rare tumor with an indolent course that occurs most commonly in the tibia. It is locally aggressive, and local recurrences are described after resection. Pain is the most common symptom. Since the lesion is typically slow growing, the pain can be present for many years before the patient seeks medical attention. Microscopically, adamantinoma consists of islands of epithelial cells in a fibrous stroma. Nuclear atypia is minimal, and mitotic figures are rare. The most common radiographic appearance is that of multiple sharply demarcated radiolucent lesions surrounded by areas of dense, sclerotic bone. This tumor most often affects the tibial diaphysis and produces lytic lesions that can cause fractures. A 31-year-old man presented with a rapidly growing lytic lesion of the distal tibia. On histological examination, many areas of epithelial cells in a fibrous stroma were identified. Diagnosis of adamantinoma was performed. The lesion was treated with en bloc resection and reconstruction with distal tibia allograft and ankle arthrodesis with retrograde nail. At 2-year follow-up, there were no clinical or radiological signs of recurrence of disease.

  10. Radiographic findings in congenital lead poisoning

    SciTech Connect

    Pearl, M.; Boxt, L.M.

    1980-07-01

    Because lead crosses the placenta throughout pregnancy, the fetus is at risk for lead poisoning. A full term, asymptomatic child was born with congenital lead poisoning secondary to maternal pica. Radiographic findings of a dense cranial vault, lead lines, and delayed skeletal and deciduous dental development were noted at birth. After chelation therapy, when the patient was seven months old, radiographs revealed normal skeletal maturation. Tooth eruption did not occur until 15 months of age. Newborn infants with these radiographic findings should be screened for subclinical, congenital lead poisoning.

  11. Compatible embedding for 2D shape animation.

    PubMed

    Baxter, William V; Barla, Pascal; Anjyo, Ken-Ichi

    2009-01-01

    We present new algorithms for the compatible embedding of 2D shapes. Such embeddings offer a convenient way to interpolate shapes having complex, detailed features. Compared to existing techniques, our approach requires less user input, and is faster, more robust, and simpler to implement, making it ideal for interactive use in practical applications. Our new approach consists of three parts. First, our boundary matching algorithm locates salient features using the perceptually motivated principles of scale-space and uses these as automatic correspondences to guide an elastic curve matching algorithm. Second, we simplify boundaries while maintaining their parametric correspondence and the embedding of the original shapes. Finally, we extend the mapping to shapes' interiors via a new compatible triangulation algorithm. The combination of our algorithms allows us to demonstrate 2D shape interpolation with instant feedback. The proposed algorithms exhibit a combination of simplicity, speed, and accuracy that has not been achieved in previous work.

  12. Schottky diodes from 2D germanane

    NASA Astrophysics Data System (ADS)

    Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.

    2016-07-01

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  13. Extrinsic Cation Selectivity of 2D Membranes

    PubMed Central

    2017-01-01

    From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333

  14. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Lin, Jerry

    1996-07-15

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  15. Explicit 2-D Hydrodynamic FEM Program

    SciTech Connect

    Lin, Jerry

    1996-08-07

    DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.

  16. Quasiparticle interference in unconventional 2D systems

    NASA Astrophysics Data System (ADS)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-01

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  17. Compact 2-D graphical representation of DNA

    NASA Astrophysics Data System (ADS)

    Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana

    2003-05-01

    We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.

  18. 2D Metals by Repeated Size Reduction.

    PubMed

    Liu, Hanwen; Tang, Hao; Fang, Minghao; Si, Wenjie; Zhang, Qinghua; Huang, Zhaohui; Gu, Lin; Pan, Wei; Yao, Jie; Nan, Cewen; Wu, Hui

    2016-10-01

    A general and convenient strategy for manufacturing freestanding metal nanolayers is developed on large scale. By the simple process of repeatedly folding and calendering stacked metal sheets followed by chemical etching, free-standing 2D metal (e.g., Ag, Au, Fe, Cu, and Ni) nanosheets are obtained with thicknesses as small as 1 nm and with sizes of the order of several micrometers.

  19. Realistic and efficient 2D crack simulation

    NASA Astrophysics Data System (ADS)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  20. Engineering light outcoupling in 2D materials.

    PubMed

    Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  1. Irreversibility-inversions in 2D turbulence

    NASA Astrophysics Data System (ADS)

    Bragg, Andrew; de Lillo, Filippo; Boffetta, Guido

    2016-11-01

    We consider a recent theoretical prediction that for inertial particles in 2D turbulence, the nature of the irreversibility of their pair dispersion inverts when the particle inertia exceeds a certain value. In particular, when the particle Stokes number, St , is below a certain value, the forward-in-time (FIT) dispersion should be faster than the backward-in-time (BIT) dispersion, but for St above this value, this should invert so that BIT becomes faster than FIT dispersion. This non-trivial behavior arises because of the competition between two physically distinct irreversibility mechanisms that operate in different regimes of St . In 3D turbulence, both mechanisms act to produce faster BIT than FIT dispersion, but in 2D, the two mechanisms have opposite effects because of the inverse energy cascade in the turbulent velocity field. We supplement the qualitative argument given by Bragg et al. by deriving quantitative predictions of this effect in the short-time dispersion limit. These predictions are then confirmed by results of inertial particle dispersion in a direct numerical simulation of 2D turbulence.

  2. A volumetric model-based 2D to 3D registration method for measuring kinematics of natural knees with single-plane fluoroscopy

    SciTech Connect

    Tsai, Tsung-Yuan; Lu, Tung-Wu; Chen, Chung-Ming; Kuo, Mei-Ying; Hsu, Horng-Chaung

    2010-03-15

    Purpose: Accurate measurement of the three-dimensional (3D) rigid body and surface kinematics of the natural human knee is essential for many clinical applications. Existing techniques are limited either in their accuracy or lack more realistic experimental evaluation of the measurement errors. The purposes of the study were to develop a volumetric model-based 2D to 3D registration method, called the weighted edge-matching score (WEMS) method, for measuring natural knee kinematics with single-plane fluoroscopy to determine experimentally the measurement errors and to compare its performance with that of pattern intensity (PI) and gradient difference (GD) methods. Methods: The WEMS method gives higher priority to matching of longer edges of the digitally reconstructed radiograph and fluoroscopic images. The measurement errors of the methods were evaluated based on a human cadaveric knee at 11 flexion positions. Results: The accuracy of the WEMS method was determined experimentally to be less than 0.77 mm for the in-plane translations, 3.06 mm for out-of-plane translation, and 1.13 deg. for all rotations, which is better than that of the PI and GD methods. Conclusions: A new volumetric model-based 2D to 3D registration method has been developed for measuring 3D in vivo kinematics of natural knee joints with single-plane fluoroscopy. With the equipment used in the current study, the accuracy of the WEMS method is considered acceptable for the measurement of the 3D kinematics of the natural knee in clinical applications.

  3. 2D superconductivity by ionic gating

    NASA Astrophysics Data System (ADS)

    Iwasa, Yoshi

    2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially

  4. Fragile watermarking using the VW2D watermark

    NASA Astrophysics Data System (ADS)

    Wolfgang, Raymond B.; Delp, Edward J., III

    1999-04-01

    Two classes of digital watermarks have been developed to protect the copyright ownership of digital images. Robust watermarks are designed to withstand attacks on an image (such as compression or scaling), while fragile watermarks are designed to detect minute changes in an image. Fragile marks can also identify where an image has been altered. This paper compares two fragile watermarks. The first method uses a hash function to obtain a digest of the image. An altered or forged version of the original image is then hashed and the digest is compared to the digest of the original image. If the image has changed the digests will be different. We will describe how images can be hashed so that any changes can be spatially localized. The second method uses the Variable-Watermark Two- Dimensional algorithm (VW2D). The sensitivity to changes is user-specific. Either no changes can be permitted (similar to a hard hash function), or an image can be altered and still be labeled authentic. Latter algorithms are known as semi-fragile watermarks. We will describe the performance of these two techniques and discuss under what circumstances one would use a particular technique.

  5. Photorealistic image synthesis and camera validation from 2D images

    NASA Astrophysics Data System (ADS)

    Santos Ferrer, Juan C.; González Chévere, David; Manian, Vidya

    2014-06-01

    This paper presents a new 3D scene reconstruction technique using the Unity 3D game engine. The method presented here allow us to reconstruct the shape of simple objects and more complex ones from multiple 2D images, including infrared and digital images from indoor scenes and only digital images from outdoor scenes and then add the reconstructed object to the simulated scene created in Unity 3D, these scenes are then validated with real world scenes. The method used different cameras settings and explores different properties in the reconstructions of the scenes including light, color, texture, shapes and different views. To achieve the highest possible resolution, it was necessary the extraction of partial textures from visible surfaces. To recover the 3D shapes and the depth of simple objects that can be represented by the geometric bodies, there geometric characteristics were used. To estimate the depth of more complex objects the triangulation method was used, for this the intrinsic and extrinsic parameters were calculated using geometric camera calibration. To implement the methods mentioned above the Matlab tool was used. The technique presented here also let's us to simulate small simple videos, by reconstructing a sequence of multiple scenes of the video separated by small margins of time. To measure the quality of the reconstructed images and video scenes the Fast Low Band Model (FLBM) metric from the Video Quality Measurement (VQM) software was used. Low bandwidth perception based features include edges and motion.

  6. Evaluation of similarity measures for use in the intensity-based rigid 2D-3D registration for patient positioning in radiotherapy

    SciTech Connect

    Wu Jian; Kim, Minho; Peters, Jorg; Chung, Heeteak; Samant, Sanjiv S.

    2009-12-15

    Purpose: Rigid 2D-3D registration is an alternative to 3D-3D registration for cases where largely bony anatomy can be used for patient positioning in external beam radiation therapy. In this article, the authors evaluated seven similarity measures for use in the intensity-based rigid 2D-3D registration using a variation in Skerl's similarity measure evaluation protocol. Methods: The seven similarity measures are partitioned intensity uniformity, normalized mutual information (NMI), normalized cross correlation (NCC), entropy of the difference image, pattern intensity (PI), gradient correlation (GC), and gradient difference (GD). In contrast to traditional evaluation methods that rely on visual inspection or registration outcomes, the similarity measure evaluation protocol probes the transform parameter space and computes a number of similarity measure properties, which is objective and optimization method independent. The variation in protocol offers an improved property in the quantification of the capture range. The authors used this protocol to investigate the effects of the downsampling ratio, the region of interest, and the method of the digitally reconstructed radiograph (DRR) calculation [i.e., the incremental ray-tracing method implemented on a central processing unit (CPU) or the 3D texture rendering method implemented on a graphics processing unit (GPU)] on the performance of the similarity measures. The studies were carried out using both the kilovoltage (kV) and the megavoltage (MV) images of an anthropomorphic cranial phantom and the MV images of a head-and-neck cancer patient. Results: Both the phantom and the patient studies showed the 2D-3D registration using the GPU-based DRR calculation yielded better robustness, while providing similar accuracy compared to the CPU-based calculation. The phantom study using kV imaging suggested that NCC has the best accuracy and robustness, but its slow function value change near the global maximum requires a

  7. Image-processing technique for suppressing ribs in chest radiographs by means of massive training artificial neural network (MTANN).

    PubMed

    Suzuki, Kenji; Abe, Hiroyuki; MacMahon, Heber; Doi, Kunio

    2006-04-01

    When lung nodules overlap with ribs or clavicles in chest radiographs, it can be difficult for radiologists as well as computer-aided diagnostic (CAD) schemes to detect these nodules. In this paper, we developed an image-processing technique for suppressing the contrast of ribs and clavicles in chest radiographs by means of a multiresolution massive training artificial neural network (MTANN). An MTANN is a highly nonlinear filter that can be trained by use of input chest radiographs and the corresponding "teaching" images. We employed "bone" images obtained by use of a dual-energy subtraction technique as the teaching images. For effective suppression of ribs having various spatial frequencies, we developed a multiresolution MTANN consisting of multiresolution decomposition/composition techniques and three MTANNs for three different-resolution images. After training with input chest radiographs and the corresponding dual-energy bone images, the multiresolution MTANN was able to provide "bone-image-like" images which were similar to the teaching bone images. By subtracting the bone-image-like images from the corresponding chest radiographs, we were able to produce "soft-tissue-image-like" images where ribs and clavicles were substantially suppressed. We used a validation test database consisting of 118 chest radiographs with pulmonary nodules and an independent test database consisting of 136 digitized screen-film chest radiographs with 136 solitary pulmonary nodules collected from 14 medical institutions in this study. When our technique was applied to nontraining chest radiographs, ribs and clavicles in the chest radiographs were suppressed substantially, while the visibility of nodules and lung vessels was maintained. Thus, our image-processing technique for rib suppression by means of a multiresolution MTANN would be potentially useful for radiologists as well as for CAD schemes in detection of lung nodules on chest radiographs.

  8. Solid state radiographic image amplifiers, part C

    NASA Technical Reports Server (NTRS)

    Szepesi, Z.

    1971-01-01

    The contrast sensitivity of the radiographic amplifiers, both the storage type and nonstorage type, their absolute sensitivity, and the reproducibility of fabrication were investigated. The required 2-2T quality level was reached with the radiographic storage screen. The sensitivity threshold was 100 to 200 mR with 45 to 100 kV filtered X-rays. The quality level of the radiographic amplifier screen (without storage) was 4-4T; for a 6 mm (0.25 in.) thick aluminum specimen, a 1 mm (0.040 in.) diameter hole in a 0.25 mm (0.010 in.) thick penetrameter was detected. Its sensitivity threshold was 2 to 6 mR/min. The developed radiographic screens are applicable for uses in nondestructive testing.

  9. Radiographic selection criteria: new guidelines, old challenges.

    PubMed

    Horner, K

    2013-02-01

    Radiographic selection criteria are a legal requirement for any establishment using ionising radiation for medical purposes, including dental practices. The Faculty of General Dental Practice (UK) pioneered the development of radiographic selection criteria for dentistry in the UK in 1998 and followed this with a second edition in 2004. This year will see a third edition, updated by new research evidence and developments in X-ray imaging for dentistry, including cone beam computed tomography (CT). Radiographic selection criteria are not rules but are one form of clinical guideline designed to help in clinical decision making. There are many influences on the use of radiography in dental practice including non-clinical factors. Evidence-based radiographic selection criteria can help to reinforce good practice, but require a multi-faceted implementation strategy including incorporation into clinical audit, easy availability to users and education.

  10. Film adhesive enhances neutron radiographic images

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1978-01-01

    Resolution of neutron radiographic images of thermally conductive film is increased by replacing approximately 5 percent of aluminum powder, which provides thermal conductivity, with gadolinium oxide. Oxide is also chemically stable.

  11. Gastroduodenal lesions of ingested acids: radiographic findings.

    PubMed

    Muhletaler, C A; Gerlock, A J; de Soto, L; Halter, S A

    1980-12-01

    Abdominal radiographs and barium studies of the stomach and duodenum of 27 patients after ingestion of muriatic acid (27% HCl) in suicidal attempts were reviewed. Eleven patients were studied in the acute phase (1-10 days), nine in the subacute phase (11-20 days), and 15 in the chronic phase (21 days or more). Extensive gastric and duodenal mucosal and submucosal damage was radiographically demonstrated in all patients studied in the acute and subacute phase. Four patients had gastric perforation. The radiographic findings in the chronic phase were characterized by marked contraction of the lesser curvature, antral stenosis, irregular gastric contours, and deformed duodenal bulb. Esophageal mucosal and submucosal lesions were radiographically demonstrated in all these patients.

  12. Method prevents secondary radiation in radiographic inspection

    NASA Technical Reports Server (NTRS)

    Struckus, A. A.

    1967-01-01

    Thin-walled neoprene containers prevent secondary radiation, scatter, and undercut during radiographic inspection. The containers are filled with a mixture of barium sulfate, red lead, and petroleum jelly that achieves the required absorption rate.

  13. The forensic importance of frontal sinus radiographs.

    PubMed

    da Silva, Rhonan Ferreira; Prado, Felippe Bevilacqua; Caputo, Isamara Geandra Cavalcanti; Devito, Karina Lopes; Botelho, Tessa de Luscena; Daruge Júnior, Eduardo

    2009-01-01

    The identification of unidentified human remains through the comparison of antemortem and postmortem radiographs has found wide acceptance in recent years. Reported here is the forensic case of an unidentified adult male who had died as the result of a traffic accident, after which the body was identified by matching images of ante- and postmortem radiographs of the frontal sinus. A general discussion on identification using frontal sinus radiographs is presented, highlighting the reliability of this method, in reference to the uniqueness of the frontal sinus in humans. However, it also notes a few difficulties, especially in reference to the X-ray technique in cases where antemortem radiographs are available and a potentially larger number of anatomical, pathological or traumatic features are present. The comparison of frontal sinus outlines is recommended when it may become necessary to provide quantitative substantiation for forensic identification based on these structures.

  14. Silicene: silicon conquers the 2D world

    NASA Astrophysics Data System (ADS)

    Le Lay, Guy; Salomon, Eric; Angot, Thierry

    2016-01-01

    We live in the digital age based on the silicon chip and driven by Moore's law. Last July, IBM created a surprise by announcing the fabrication of a 7 nm test chip with functional transistors using, instead of just silicon, a silicon-germanium alloy. Will silicon be dethroned?

  15. Lead Scales for X-Radiographs

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Adams, James F.

    1987-01-01

    Indentations made by typing on lead tape. Lead scales for inclusion in x-radiographs as length and position references created by repeatedly imprinting character like upper-case I, L, or V, or lower-case L into lead tape with typewriter. Character pitch of typewriter serves as length reference for scale. Thinning of tape caused by impacts of type shows up dark in radiograph.

  16. Radiation recommendation series: administratively required dental radiographs

    SciTech Connect

    Not Available

    1981-09-01

    Administrative requirements for radiographs are found in many segments of the United States health care system. This document presents an FDA radiation recommendation on administratively required dental x-ray examinations. In general, such examinations are not requested to further the patient's dental health, but rather as a means of monitoring claims. However, the administrative use of radiographs that have been taken in the normal course of patient care is usually appropriate, as long as the patient's right to privacy is respected.

  17. Radiographic signs and diagnosis of dental disease.

    PubMed

    Bellows, J

    1993-08-01

    Dental radiographs are critical for the complete assessment and treatment of dental diseases. Dental radiography is commonly used to evaluate congenital dental defects, periodontal disease, orthodontic manipulations, oral tumors, endodontic treatments, oral trauma, and any situation where an abnormality is suspected. Although standard radiographic equipment and film can be used to produce dental radiographs, dental X-ray equipment and film provide superior quality images and greater convenience of animal patient positioning. An understanding of normal dental radiographic anatomy is important when interpreting dental radiographs. Stage III periodontitis is the earliest stage of periodontal disease at which radiographic abnormalities become apparent. Bone loss associated with periodontal disease can be classified as either horizontal or vertical. Periapical radiolucencies can represent granulomas, cysts, or abscesses, whereas periapical radiodensities may represent sclerotic bone or condensing osteitis. Lytic lesions of the bone of the jaw often represent oral neoplasms. Neoplasms also can displace or disrupt teeth in the dental arch. Resorptive lesions can be external or internal and appear as radiolucent areas involving the external surface of the root or the pulp cavity, respectively. Feline dental resorptive lesions, also known as odontoclastic resorptions, are a specific form of dental resorptive lesions unique to cats.

  18. Can exposure to prenatal sex hormones (2D:4D) predict cognitive reflection?

    PubMed

    Bosch-Domènech, Antoni; Brañas-Garza, Pablo; Espín, Antonio M

    2014-05-01

    The Cognitive Reflection Test (CRT) is a test introduced by Frederick (2005). The task is designed to measure the tendency to override an intuitive response that is incorrect and to engage in further reflection that leads to the correct response. The consistent sex differences in CRT performance may suggest a role for prenatal sex hormones. A now widely studied putative marker for relative prenatal testosterone is the second-to-fourth digit ratio (2D:4D). This paper tests to what extent 2D:4D, as a proxy for the prenatal ratio of testosterone/estrogens, can predict CRT scores in a sample of 623 students. After controlling for sex, we observe that a lower 2D:4D (reflecting a relative higher exposure to testosterone) is significantly associated with a higher number of correct answers. The result holds for both hands' 2D:4Ds. In addition, the effect appears to be stronger for females than for males. We also control for patience and math proficiency, which are significantly related to performance in the CRT. But the effect of 2D:4D on performance in CRT is not reduced with these controls, implying that these variables are not mediating the relationship between digit ratio and CRT.

  19. A comparative study of the diagnostic capabilities of 2D plain radiograph and 3D cone beam CT sialography

    PubMed Central

    Jadu, FM; Lam, EWN

    2013-01-01

    Objective The aim of this study was to compare the diagnostic capabilities of two-dimensional sialography with a novel three-dimensional technique using cone beam CT (CBCT). Methods 47 subjects underwent parotid or submandibular gland sialography over a 2 year period using both plain imaging and CBCT. Both image sets were anonymized and independently reviewed by three certified oral and maxillofacial radiologists blinded to the clinical data. McNemar's χ2 test was used to determine differences between the two modalities for feature visualization and interpretation. Results CBCT outperformed plain imaging with respect to visualization of the gland parenchyma (p < 0.001) and identification of sialoliths (p = 0.02). Plain imaging outperformed CBCT for the identification of strictures (p = 0.04); however, the negative per cent agreement (“specificity”) between the two imaging modalities was 100%. Although both imaging modalities performed equally in identifying normal and abnormal sialographic examinations, CBCT demonstrated a high negative per cent agreement for normal glands and a high positive per cent agreement (“sensitivity”) for abnormal glands with inflammatory changes. Conclusion CBCT sialography allowed better visualization of gland parenchyma and identification of sialoliths. The high negative per cent agreement for strictures suggests that, if strictures are identified on CBCT images, then obstruction can be ruled in. Relative to plain images, the high negative per cent agreement for normal glands suggests that, if an abnormal finding is detected on CBCT images, then disease can be ruled in, and the high positive per cent agreement for glands with inflammatory changes suggests that inflammation can be ruled out if these changes are not seen on CBCT images. PMID:23253564

  20. An integrated system for 3D hip joint reconstruction from 2D X-rays: a preliminary validation study.

    PubMed

    Schumann, Steffen; Liu, Li; Tannast, Moritz; Bergmann, Mathias; Nolte, Lutz-P; Zheng, Guoyan

    2013-10-01

    The acquisition of conventional X-ray radiographs remains the standard imaging procedure for the diagnosis of hip-related problems. However, recent studies demonstrated the benefit of using three-dimensional (3D) surface models in the clinical routine. 3D surface models of the hip joint are useful for assessing the dynamic range of motion in order to identify possible pathologies such as femoroacetabular impingement. In this paper, we present an integrated system which consists of X-ray radiograph calibration and subsequent 2D/3D hip joint reconstruction for diagnosis and planning of hip-related problems. A mobile phantom with two different sizes of fiducials was developed for X-ray radiograph calibration, which can be robustly detected within the images. On the basis of the calibrated X-ray images, a 3D reconstruction method of the acetabulum was developed and applied together with existing techniques to reconstruct a 3D surface model of the hip joint. X-ray radiographs of dry cadaveric hip bones and one cadaveric specimen with soft tissue were used to prove the robustness of the developed fiducial detection algorithm. Computed tomography scans of the cadaveric bones were used to validate the accuracy of the integrated system. The fiducial detection sensitivity was in the same range for both sizes of fiducials. While the detection sensitivity was 97.96% for the large fiducials, it was 97.62% for the small fiducials. The acetabulum and the proximal femur were reconstructed with a mean surface distance error of 1.06 and 1.01 mm, respectively. The results for fiducial detection sensitivity and 3D surface reconstruction demonstrated the capability of the integrated system for 3D hip joint reconstruction from 2D calibrated X-ray radiographs.

  1. Periodically sheared 2D Yukawa systems

    SciTech Connect

    Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  2. ENERGY LANDSCAPE OF 2D FLUID FORMS

    SciTech Connect

    Y. JIANG; ET AL

    2000-04-01

    The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.

  3. Codon Constraints on Closed 2D Shapes,

    DTIC Science & Technology

    2014-09-26

    19843$ CODON CONSTRAINTS ON CLOSED 2D SHAPES Go Whitman Richards "I Donald D. Hoffman’ D T 18 Abstract: Codons are simple primitives for describing plane...RSONAL AUT"ORtIS) Richards, Whitman & Hoffman, Donald D. 13&. TYPE OF REPORT 13b. TIME COVERED N/A P8 AT F RRrT t~r. Ago..D,) is, PlE COUNT Reprint...outlines, if figure and ground are ignored. Later, we will address the problem of indexing identical codon descriptors that have different figure

  4. Radiographic Evaluation of Mandible to Predict the Gender and Age

    PubMed Central

    Kumar, Jyothi Shiv; Mohan, Vinay

    2014-01-01

    Purpose: This study is been conducted using digital panoramic radiographs for predicting age in various age groups and the accuracy of the parameters were accessed as age advances. Materials and Methods: The selected 300 panoramic images were divided into 3 age group of Group A (25-34 years), Group B (35-44 years), and Group C (45 -54 years). Each group comprised of 100 subjects in which 50 were males & 50 females. The age changes were evaluated using five parameters collectively, which were: Gonial angle, Antegonial angle, Mental foramen, Mandibular canal, Mandibular foramen. These parameters were evaluated on panoramic radiographs for age prediction and changes in their position as age advances. Results: Among all the parameters changes in Mandibular canal and mandibular foramen was found to be highly significant (p value ≤0.05) as age advances. Conclusion: These parameters can be used to predict the age of the individual as there were significant changes in Mandibular canal and Mandibular foramen as age advances. For Further studies large sample size, and recent modalities in radiography like CBCT or CT scan are required. PMID:25478451

  5. Remarks on thermalization in 2D CFT

    NASA Astrophysics Data System (ADS)

    de Boer, Jan; Engelhardt, Dalit

    2016-12-01

    We revisit certain aspects of thermalization in 2D conformal field theory (CFT). In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a Banados-Teitelboim-Zanelli black hole. The extra conserved charges, while rendering c <1 theories essentially integrable, therefore seem to have little effect on large-c conformal field theories.

  6. Microwave Assisted 2D Materials Exfoliation

    NASA Astrophysics Data System (ADS)

    Wang, Yanbin

    Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.

  7. The 2D:4D ratio of the hand and schizotypal personality traits in schizophrenia patients and healthy control persons.

    PubMed

    Zhu, Yi-Kang; Li, Chun-Bo; Jin, Jin; Wang, Ji-Jun; Lachmann, Bernd; Sariyska, Rayna; Montag, Christian

    2014-06-01

    Prenatal estrogen/testosterone exposure is known to be involved in early brain development. In this context, the ratio of the index finger to ring finger length (2D:4D) has been put forward as an indicator of the intrauterine sex hormonal level. A previous study by Collinson et al. (2010) examined 2D:4D ratios in Asian patients with schizophrenia and found an increased 2D:4D pattern in male patients compared to male healthy controls. In the current study, we tried to replicate the result of this study on the 2D:4D ratio in schizophrenia patients and controls in a Chinese sample. Moreover, we investigated the link between 2D:4D ratios and schizotypal personality traits in the participants of the study. No significant difference between cases and controls in 2D:4D ratios for both hands could be observed. However, a positive association between right 2D:4D ratio and schizotypal personality traits was found in healthy controls (both in the male and female subsamples) suggesting that a high 2D:4D ratio could represent a vulnerability factor for schizophrenia in healthy males and females. Same results were observed for the digit ratio of the left hand and the SPQ in the healthy total and healthy female subsample. Therefore, the inclusion of personality measures to study the link between the digit ratio and schizophrenia might help to provide insights in a potential continuum from healthy to schizophrenic behavior.

  8. Reducing missing fracture clinic radiographs by entrusting them to patients.

    PubMed Central

    Calder, Peter R.; Hynes, Matthew C.; Goodier, W. David

    2004-01-01

    BACKGROUND: Missing radiographs in fracture clinics may compromise fracture management and lead to inappropriate use of clerical resources. METHODS: We prospectively compared the number of missing radiographs in two hospitals over a period of two months. In hospital A the radiographs were retained and in hospital B they were entrusted to the patients. RESULTS: At the completion of the study, entrusting patients with their radiographs resulted in statistically less radiographs missing from the clinic. PMID:15333169

  9. 2-D or not 2-D, that is the question: A Northern California test

    SciTech Connect

    Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D

    2005-06-06

    Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is still preferable over 2

  10. A positioning QA procedure for 2D/2D (kV/MV) and 3D/3D (CT/CBCT) image matching for radiotherapy patient setup.

    PubMed

    Guan, Huaiqun; Hammoud, Rabih; Yin, Fang-Fang

    2009-10-06

    A positioning QA procedure for Varian's 2D/2D (kV/MV) and 3D/3D (planCT/CBCT) matching was developed. The procedure was to check: (1) the coincidence of on-board imager (OBI), portal imager (PI), and cone beam CT (CBCT)'s isocenters (digital graticules) to a linac's isocenter (to a pre-specified accuracy); (2) that the positioning difference detected by 2D/2D (kV/MV) and 3D/3D(planCT/CBCT) matching can be reliably transferred to couch motion. A cube phantom with a 2 mm metal ball (bb) at the center was used. The bb was used to define the isocenter. Two additional bbs were placed on two phantom surfaces in order to define a spatial location of 1.5 cm anterior, 1.5 cm inferior, and 1.5 cm right from the isocenter. An axial scan of the phantom was acquired from a multislice CT simulator. The phantom was set at the linac's isocenter (lasers); either AP MV/R Lat kV images or CBCT images were taken for 2D/2D or 3D/3D matching, respectively. For 2D/2D, the accuracy of each device's isocenter was obtained by checking the distance between the central bb and the digital graticule. Then the central bb in orthogonal DRRs was manually moved to overlay to the off-axis bbs in kV/MV images. For 3D/3D, CBCT was first matched to planCT to check the isocenter difference between the two CTs. Manual shifts were then made by moving CBCT such that the point defined by the two off-axis bbs overlay to the central bb in planCT. (PlanCT can not be moved in the current version of OBI1.4.) The manual shifts were then applied to remotely move the couch. The room laser was used to check the accuracy of the couch movement. For Trilogy (or Ix-21) linacs, the coincidence of imager and linac's isocenter was better than 1 mm (or 1.5 mm). The couch shift accuracy was better than 2 mm.

  11. Transition to turbulence: 2D directed percolation

    NASA Astrophysics Data System (ADS)

    Chantry, Matthew; Tuckerman, Laurette; Barkley, Dwight

    2016-11-01

    The transition to turbulence in simple shear flows has been studied for well over a century, yet in the last few years has seen major leaps forward. In pipe flow, this transition shows the hallmarks of (1 + 1) D directed percolation, a universality class of continuous phase transitions. In spanwisely confined Taylor-Couette flow the same class is found, suggesting the phenomenon is generic to shear flows. However in plane Couette flow the largest simulations and experiments to-date find evidence for a discrete transition. Here we study a planar shear flow, called Waleffe flow, devoid of walls yet showing the fundamentals of planar transition to turbulence. Working with a quasi-2D yet Navier-Stokes derived model of this flow we are able to attack the (2 + 1) D transition problem. Going beyond the system sizes previously possible we find all of the required scalings of directed percolation and thus establish planar shears flow in this class.

  12. 2D quantum gravity from quantum entanglement.

    PubMed

    Gliozzi, F

    2011-01-21

    In quantum systems with many degrees of freedom the replica method is a useful tool to study the entanglement of arbitrary spatial regions. We apply it in a way that allows them to backreact. As a consequence, they become dynamical subsystems whose position, form, and extension are determined by their interaction with the whole system. We analyze, in particular, quantum spin chains described at criticality by a conformal field theory. Its coupling to the Gibbs' ensemble of all possible subsystems is relevant and drives the system into a new fixed point which is argued to be that of the 2D quantum gravity coupled to this system. Numerical experiments on the critical Ising model show that the new critical exponents agree with those predicted by the formula of Knizhnik, Polyakov, and Zamolodchikov.

  13. Simulation of Yeast Cooperation in 2D.

    PubMed

    Wang, M; Huang, Y; Wu, Z

    2016-03-01

    Evolution of cooperation has been an active research area in evolutionary biology in decades. An important type of cooperation is developed from group selection, when individuals form spatial groups to prevent them from foreign invasions. In this paper, we study the evolution of cooperation in a mixed population of cooperating and cheating yeast strains in 2D with the interactions among the yeast cells restricted to their small neighborhoods. We conduct a computer simulation based on a game theoretic model and show that cooperation is increased when the interactions are spatially restricted, whether the game is of a prisoner's dilemma, snow drifting, or mutual benefit type. We study the evolution of homogeneous groups of cooperators or cheaters and describe the conditions for them to sustain or expand in an opponent population. We show that under certain spatial restrictions, cooperator groups are able to sustain and expand as group sizes become large, while cheater groups fail to expand and keep them from collapse.

  14. 2D Electrostatic Actuation of Microshutter Arrays

    NASA Technical Reports Server (NTRS)

    Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.

    2015-01-01

    An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.

  15. Graphene suspensions for 2D printing

    NASA Astrophysics Data System (ADS)

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  16. Canard configured aircraft with 2-D nozzle

    NASA Technical Reports Server (NTRS)

    Child, R. D.; Henderson, W. P.

    1978-01-01

    A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.

  17. Numerical Evaluation of 2D Ground States

    NASA Astrophysics Data System (ADS)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  18. Impact of lossy compression on diagnostic accuracy of radiographs for periapical lesions

    NASA Technical Reports Server (NTRS)

    Eraso, Francisco E.; Analoui, Mostafa; Watson, Andrew B.; Rebeschini, Regina

    2002-01-01

    OBJECTIVES: The purpose of this study was to evaluate the lossy Joint Photographic Experts Group compression for endodontic pretreatment digital radiographs. STUDY DESIGN: Fifty clinical charge-coupled device-based, digital radiographs depicting periapical areas were selected. Each image was compressed at 2, 4, 8, 16, 32, 48, and 64 compression ratios. One root per image was marked for examination. Images were randomized and viewed by four clinical observers under standardized viewing conditions. Each observer read the image set three times, with at least two weeks between each reading. Three pre-selected sites per image (mesial, distal, apical) were scored on a five-scale score confidence scale. A panel of three examiners scored the uncompressed images, with a consensus score for each site. The consensus score was used as the baseline for assessing the impact of lossy compression on the diagnostic values of images. The mean absolute error between consensus and observer scores was computed for each observer, site, and reading session. RESULTS: Balanced one-way analysis of variance for all observers indicated that for compression ratios 48 and 64, there was significant difference between mean absolute error of uncompressed and compressed images (P <.05). After converting the five-scale score to two-level diagnostic values, the diagnostic accuracy was strongly correlated (R (2) = 0.91) with the compression ratio. CONCLUSION: The results of this study suggest that high compression ratios can have a severe impact on the diagnostic quality of the digital radiographs for detection of periapical lesions.

  19. Metrology for graphene and 2D materials

    NASA Astrophysics Data System (ADS)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  20. Improving the quality of radiographic images acquired with conical radiation beams through divergence correction and filtering

    NASA Astrophysics Data System (ADS)

    Silvani, M. I.; Almeida, G. L.; Latini, R. M.; Bellido, A. V. B.; Souza, E. S.; Lopes, R. T.

    2015-07-01

    Earlier works have shown the feasibility to correct the deformation of the attenuation map in radiographs acquired with conical radiation beams provided that the inspected object could be expressed into analytical geometry terms. This correction reduces the contribution of the main object in the radiograph, allowing thus the visualization of its otherwise concealed heterogeneities. However, the non-punctual character of the source demanded a cumbersome trial-and-error approach in order to determine the proper correction parameters for the algorithm. Within this frame, this work addresses the improvement of radiographs of specially tailored test-objects acquired with a conical beam through correction of its divergence by using the information contained in the image itself. The corrected images have afterwards undergone a filtration in the frequency domain aiming at the reduction of statistical fluctuation and noise by using a 2D Fourier transform. All radiographs have been acquired using 165Dy and 198Au gamma-ray sources produced at the Argonauta research reactor in Institutode Engenharia Nuclear - CNEN, and an X-ray sensitive imaging plate as detector. The processed images exhibit features otherwise invisible in the original ones. Their processing by conventional histogram equalization carried out for comparison purposes did not succeed to detect those features.

  1. Reconstruction of 3D lung models from 2D planning data sets for Hodgkin's lymphoma patients using combined deformable image registration and navigator channels

    SciTech Connect

    Ng, Angela; Nguyen, Thao-Nguyen; Moseley, Joanne L.; Hodgson, David C.; Sharpe, Michael B.; Brock, Kristy K.

    2010-03-15

    Purpose: Late complications (cardiac toxicities, secondary lung, and breast cancer) remain a significant concern in the radiation treatment of Hodgkin's lymphoma (HL). To address this issue, predictive dose-risk models could potentially be used to estimate radiotherapy-related late toxicities. This study investigates the use of deformable image registration (DIR) and navigator channels (NCs) to reconstruct 3D lung models from 2D radiographic planning images, in order to retrospectively calculate the treatment dose exposure to HL patients treated with 2D planning, which are now experiencing late effects. Methods: Three-dimensional planning CT images of 52 current HL patients were acquired. 12 image sets were used to construct a male and a female population lung model. 23 ''Reference'' images were used to generate lung deformation adaptation templates, constructed by deforming the population model into each patient-specific lung geometry using a biomechanical-based DIR algorithm, MORFEUS. 17 ''Test'' patients were used to test the accuracy of the reconstruction technique by adapting existing templates using 2D digitally reconstructed radiographs. The adaptation process included three steps. First, a Reference patient was matched to a Test patient by thorax measurements. Second, four NCs (small regions of interest) were placed on the lung boundary to calculate 1D differences in lung edges. Third, the Reference lung model was adapted to the Test patient's lung using the 1D edge differences. The Reference-adapted Test model was then compared to the 3D lung contours of the actual Test patient by computing their percentage volume overlap (POL) and Dice coefficient. Results: The average percentage overlapping volumes and Dice coefficient expressed as a percentage between the adapted and actual Test models were found to be 89.2{+-}3.9% (Right lung=88.8%; Left lung=89.6%) and 89.3{+-}2.7% (Right=88.5%; Left=90.2%), respectively. Paired T-tests demonstrated that the

  2. A radiographic scanning technique for cores

    USGS Publications Warehouse

    Hill, G.W.; Dorsey, M.E.; Woods, J.C.; Miller, R.J.

    1979-01-01

    A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment. Additional components include a conveyor system, antiscatter cylinder-diaphragm, adjustable sample platform, developing tanks, and a contact printer. Complete cores, half cores, sample slabs or peels may be scanned. Converting the X-ray unit from one mode to another is easy and can be accomplished without the use of special tools. RST provides the investigator with a convenient, continuous, high quality radiograph, saves time and money, and decreases the number of times cores have to be handled. ?? 1979.

  3. Centric relation determinations: clinical and radiographic comparisons.

    PubMed

    Carwell, M L; McFall, W T

    1981-07-01

    This study investigated variations in occlusal prematurities and condylar positions using different methods of determining centric relation. Thirty patients were randomly placed into three groups of 10. In Group I a clinical analysis of occlusal patterns using bilateral mandibular manipulation (BMM) was compared to results with a chin point (CPM) method. Group II compared CPM to an anterior guidance jig (CPJ) method. Group III compared BMM to CPJ. Standardized transcranial oblique radiographs were taken of each temporomandibular joint using CPM and BMM on 10 patients. Condylar position was determined with tracing evaluations and direct measurements of the radiographs. Clinical results indicated that the initial point of contact was located most accurately with CPJ. Both initial contact points and secondary points were disclosed with CPM. The BMM disclosed the most tooth contacts. Contacts were most prevalent on the premolars. Radiographic analyses of condylar positions were inconclusive.

  4. Postmortem abdominal radiographic findings in feline cadavers.

    PubMed

    Heng, Hock Gan; Teoh, Wen Tian; Sheikh-Omar, Abdul Rahman

    2008-01-01

    Postmortem radiographic examinations of animals are commonly performed in judicial investigations to rule out gunshot and fractures. However, there was no available data on radiographic postmortem changes of animals. Forty-one sets of abdominal radiographs of feline cadavers made within 12 h of death were evaluated for postmortem changes. Intravascular gas was detected in 11 of 41 (27%) cadavers. The most common site of intravascular gas was the liver. Intravascular gas was also present in the aorta, femoral artery, celiac and cranial mesenteric arteries, and caudal superficial epigastric artery. Intrasplenic gas was detected in two cadavers. Only two cadavers had distended small intestine. One cadaver had pneumatosis coli. The changes detected were most likely due to putrefaction.

  5. Method of radiographic inspection of wooden members

    NASA Technical Reports Server (NTRS)

    Berry, Maggie L. (Inventor); Berry, Robert F., Jr. (Inventor)

    1990-01-01

    The invention is a method to be used for radiographic inspection of a wooden specimen for internal defects which includes the steps of introducing a radiopaque penetrant into any internal defects in the specimen through surface openings; passing a beam of radiation through a portion of the specimen to be inspected; and making a radiographic film image of the radiation passing through the specimen, with the radiopaque penetrant in the specimen absorbing the radiation passing through it, thereby enhancing the resulting image of the internal defects in the specimen.

  6. 3D-2D registration of cerebral angiograms based on vessel directions and intensity gradients

    NASA Astrophysics Data System (ADS)

    Mitrovic, Uroš; Špiclin, Žiga; Štern, Darko; Markelj, Primož; Likar, Boštjan; Miloševic, Zoran; Pernuš, Franjo

    2012-02-01

    Endovascular treatment of cerebral aneurysms and arteriovenous malformations (AVM) involves navigation of a catheter through the femoral artery and vascular system to the site of pathology. Intra-interventional navigation is done under the guidance of one or at most two two-dimensional (2D) X-ray fluoroscopic images or 2D digital subtracted angiograms (DSA). Due to the projective nature of 2D images, the interventionist needs to mentally reconstruct the position of the catheter in respect to the three-dimensional (3D) patient vasculature, which is not a trivial task. By 3D-2D registration of pre-interventional 3D images like CTA, MRA or 3D-DSA and intra-interventional 2D images, intra-interventional tools such as catheters can be visualized on the 3D model of patient vasculature, allowing easier and faster navigation. Such a navigation may consequently lead to the reduction of total ionizing dose and delivered contrast medium. In the past, development and evaluation of 3D-2D registration methods for endovascular treatments received considerable attention. The main drawback of these methods is that they have to be initialized rather close to the correct position as they mostly have a rather small capture range. In this paper, a novel registration method that has a higher capture range and success rate is proposed. The proposed method and a state-of-the-art method were tested and evaluated on synthetic and clinical 3D-2D image-pairs. The results on both databases indicate that although the proposed method was slightly less accurate, it significantly outperformed the state-of-the-art 3D-2D registration method in terms of robustness measured by capture range and success rate.

  7. Validation for 2D/3D registration I: A new gold standard data set

    SciTech Connect

    Pawiro, S. A.; Markelj, P.; Pernus, F.; Gendrin, C.; Figl, M.; Weber, C.; Kainberger, F.; Noebauer-Huhmann, I.; Bergmeister, H.; Stock, M.; Georg, D.; Bergmann, H.; Birkfellner, W.

    2011-03-15

    Purpose: In this article, the authors propose a new gold standard data set for the validation of two-dimensional/three-dimensional (2D/3D) and 3D/3D image registration algorithms. Methods: A gold standard data set was produced using a fresh cadaver pig head with attached fiducial markers. The authors used several imaging modalities common in diagnostic imaging or radiotherapy, which include 64-slice computed tomography (CT), magnetic resonance imaging using Tl, T2, and proton density sequences, and cone beam CT imaging data. Radiographic data were acquired using kilovoltage and megavoltage imaging techniques. The image information reflects both anatomy and reliable fiducial marker information and improves over existing data sets by the level of anatomical detail, image data quality, and soft-tissue content. The markers on the 3D and 2D image data were segmented using ANALYZE 10.0 (AnalyzeDirect, Inc., Kansas City, KN) and an in-house software. Results: The projection distance errors and the expected target registration errors over all the image data sets were found to be less than 2.71 and 1.88 mm, respectively. Conclusions: The gold standard data set, obtained with state-of-the-art imaging technology, has the potential to improve the validation of 2D/3D and 3D/3D registration algorithms for image guided therapy.

  8. Lateral cephalometric radiograph versus lateral nasopharyngeal radiograph for quantitative evaluation of nasopharyngeal airway space

    PubMed Central

    Pereira, Suelen Cristina da Costa; Beltrão, Rejane Targino Soares; Janson, Guilherme; Garib, Daniela Gamba

    2014-01-01

    Objective This study compared lateral radiographs of the nasopharynx (LN) and lateral cephalometric radiographs (LC) used to assess nasopharyngeal airway space in children. Material and Methods One examiner measured the nasopharyngeal space of 15 oral breathing patients aged between 5 and 11 years old by using LN and LC. Both assessments were made twice with a 15-day interval in between. Intergroup comparison was performed with t-tests (P < 0.05). Results Comparison between LN and LC measurements showed no significant differences. Conclusion Lateral cephalometric radiograph is an acceptable method used to assess nasopharyngeal airway space. PMID:25279526

  9. Persistence Measures for 2d Soap Froth

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Ruskin, H. J.; Zhu, B.

    Soap froths as typical disordered cellular structures, exhibiting spatial and temporal evolution, have been studied through their distributions and topological properties. Recently, persistence measures, which permit representation of the froth as a two-phase system, have been introduced to study froth dynamics at different length scales. Several aspects of the dynamics may be considered and cluster persistence has been observed through froth experiment. Using a direct simulation method, we have investigated persistent properties in 2D froth both by monitoring the persistence of survivor cells, a topologically independent measure, and in terms of cluster persistence. It appears that the area fraction behavior for both survivor and cluster persistence is similar for Voronoi froth and uniform froth (with defects). Survivor and cluster persistent fractions are also similar for a uniform froth, particularly when geometries are constrained, but differences observed for the Voronoi case appear to be attributable to the strong topological dependency inherent in cluster persistence. Survivor persistence, on the other hand, depends on the number rather than size and position of remaining bubbles and does not exhibit the characteristic decay to zero.

  10. SEM signal emulation for 2D patterns

    NASA Astrophysics Data System (ADS)

    Sukhov, Evgenii; Muelders, Thomas; Klostermann, Ulrich; Gao, Weimin; Braylovska, Mariya

    2016-03-01

    The application of accurate and predictive physical resist simulation is seen as one important use model for fast and efficient exploration of new patterning technology options, especially if fully qualified OPC models are not yet available at an early pre-production stage. The methodology of using a top-down CD-SEM metrology to extract the 3D resist profile information, such as the critical dimension (CD) at various resist heights, has to be associated with a series of presumptions which may introduce such small, but systematic CD errors. Ideally, the metrology effects should be carefully minimized during measurement process, or if possible be taken into account through proper metrology modeling. In this paper we discuss the application of a fast SEM signal emulation describing the SEM image formation. The algorithm is applied to simulated resist 3D profiles and produces emulated SEM image results for 1D and 2D patterns. It allows estimating resist simulation quality by comparing CDs which were extracted from the emulated and from the measured SEM images. Moreover, SEM emulation is applied for resist model calibration to capture subtle error signatures through dose and defocus. Finally, it should be noted that our SEM emulation methodology is based on the approximation of physical phenomena which are taking place in real SEM image formation. This approximation allows achieving better speed performance compared to a fully physical model.

  11. Competing coexisting phases in 2D water

    NASA Astrophysics Data System (ADS)

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-05-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.

  12. Competing coexisting phases in 2D water

    PubMed Central

    Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire

    2016-01-01

    The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018

  13. 2D/3D registration algorithm for lung brachytherapy

    SciTech Connect

    Zvonarev, P. S.; Farrell, T. J.; Hunter, R.; Wierzbicki, M.; Hayward, J. E.; Sur, R. K.

    2013-02-15

    Purpose: A 2D/3D registration algorithm is proposed for registering orthogonal x-ray images with a diagnostic CT volume for high dose rate (HDR) lung brachytherapy. Methods: The algorithm utilizes a rigid registration model based on a pixel/voxel intensity matching approach. To achieve accurate registration, a robust similarity measure combining normalized mutual information, image gradient, and intensity difference was developed. The algorithm was validated using a simple body and anthropomorphic phantoms. Transfer catheters were placed inside the phantoms to simulate the unique image features observed during treatment. The algorithm sensitivity to various degrees of initial misregistration and to the presence of foreign objects, such as ECG leads, was evaluated. Results: The mean registration error was 2.2 and 1.9 mm for the simple body and anthropomorphic phantoms, respectively. The error was comparable to the interoperator catheter digitization error of 1.6 mm. Preliminary analysis of data acquired from four patients indicated a mean registration error of 4.2 mm. Conclusions: Results obtained using the proposed algorithm are clinically acceptable especially considering the complications normally encountered when imaging during lung HDR brachytherapy.

  14. Simultaneous 2D Doppler backscattering from edge turbulence

    NASA Astrophysics Data System (ADS)

    Thomas, David; Brunner, Kai; Freethy, Simon; Huang, Billy; Shevchenko, Vladimir; Vann, Roddy

    2015-11-01

    The Synthetic Aperture Microwave Imaging (SAMI) diagnostic (previously at MAST and now at NSTX-U) actively probes the plasma edge using a wide (80 degree beam width) and broadband (10-34.5 GHz) beam. It digitizes the phase and amplitude of the Doppler backscattered signal using a receiving array of eight antennas which can be focused in any direction post shot to an angular range of 6-24 degree FWHM. This allows Doppler BackScattering (DBS) experiments to be conducted in every direction within the field of view simultaneously. This capability is unique to SAMI and is a novel way of conducting DBS experiments. SAMI has measured the magnetic pitch angle in the edge for the first time using a backscattering diagnostic. This is possible with simultaneous 2D DBS because the maximum backscattered power is perpendicular to the turbulence and turbulence is elongated along the magnetic field. SAMI has also studied the effect of NBI and the L-H transition on turbulent velocity, and turbulence suppression in the edge during H-mode. Initial results from all of these studies will be presented. This work is supported by the Engineering and Physical Sciences Research Council Grants EP/K504178 and EP/H016732.

  15. Accuracy of Panoramic Radiograph in Assessment of the Relationship Between Mandibular Canal and Impacted Third Molars

    PubMed Central

    Tantanapornkul, Weeraya; Mavin, Darika; Prapaiphittayakun, Jaruthai; Phipatboonyarat, Natnicha; Julphantong, Wanchanok

    2016-01-01

    Background: The relationship between impacted mandibular third molar and mandibular canal is important for removal of this tooth. Panoramic radiography is one of the commonly used diagnostic tools for evaluating the relationship of these two structures. Objectives: To evaluate the accuracy of panoramic radiographic findings in predicting direct contact between mandibular canal and impacted third molars on 3D digital images, and to define panoramic criterion in predicting direct contact between the two structures. Methods: Two observers examined panoramic radiographs of 178 patients (256 impacted mandibular third molars). Panoramic findings of interruption of mandibular canal wall, isolated or with darkening of third molar root, diversion of mandibular canal and narrowing of third molar root were evaluated for 3D digital radiography. Direct contact between mandibular canal and impacted third molars on 3D digital images was then correlated with panoramic findings. Panoramic criterion was also defined in predicting direct contact between the two structures. Results: Panoramic findings of interruption of mandibular canal wall, isolated or with darkening of third molar root were statistically significantly correlated with direct contact between mandibular canal and impacted third molars on 3D digital images (p < 0.005), and were defined as panoramic criteria in predicting direct contact between the two structures. Conclusion: Interruption of mandibular canal wall, isolated or with darkening of third molar root observed on panoramic radiographs were effective in predicting direct contact between mandibular canal and impacted third molars on 3D digital images. Panoramic radiography is one of the efficient diagnostic tools for pre-operative assessment of impacted mandibular third molars. PMID:27398105

  16. Radiofrequency Spectroscopy and Thermodynamics of Fermi Gases in the 2D to Quasi-2D Dimensional Crossover

    NASA Astrophysics Data System (ADS)

    Cheng, Chingyun; Kangara, Jayampathi; Arakelyan, Ilya; Thomas, John

    2016-05-01

    We tune the dimensionality of a strongly interacting degenerate 6 Li Fermi gas from 2D to quasi-2D, by adjusting the radial confinement of pancake-shaped clouds to control the radial chemical potential. In the 2D regime with weak radial confinement, the measured pair binding energies are in agreement with 2D-BCS mean field theory, which predicts dimer pairing energies in the many-body regime. In the qausi-2D regime obtained with increased radial confinement, the measured pairing energy deviates significantly from 2D-BCS theory. In contrast to the pairing energy, the measured radii of the cloud profiles are not fit by 2D-BCS theory in either the 2D or quasi-2D regimes, but are fit in both regimes by a beyond mean field polaron-model of the free energy. Supported by DOE, ARO, NSF, and AFOSR.

  17. Acquisition hardware for digital imaging.

    PubMed

    Widmer, William R

    2008-01-01

    Use of digital radiography is growing rapidly in veterinary medicine. Two basic digital imaging systems are available, computed radiography (CR) and direct digital radiography (DDR). Computed radiographic detectors use a two-step process for image capture and processing. Image capture is by X-ray sensitive phosphors in the image plate. The image plate reader transforms the latent phosphor image to light photons that are converted to an analog electrical signal. An analog to digital converter is used to digitize the electrical signal before computer analysis. Direct digital detectors provide digital data by direct readout after image capture--a reader unnecessary. Types of DDR detectors are flat panel detectors and charge coupled device (CCD) detectors. Flat panel detectors are composed of layers of semiconductors for image capture with transistor and microscopic circuitry embedded in a pixel array. Direct converting flat panel detectors convert incident X-rays directly into electrical charges. Indirect detectors convert X-rays to visible light, then to electrical charges. All flat panel detectors send a digitized electrical signal to a computer using a direct link. Charge coupled device detectors have a small chip similar to those used in digital cameras. A scintillator first converts X-rays to a light signal that is minified by an optical system before reaching the chip. The chip sends a digital signal directly to a computer. Both CR and DDR provide quality diagnostic images. CR is a mature technology while DDR is an emerging technology.

  18. Detecting objects in radiographs for homeland security

    NASA Astrophysics Data System (ADS)

    Prasad, Lakshman; Snyder, Hans

    2005-05-01

    We present a general scheme for segmenting a radiographic image into polygons that correspond to visual features. This decomposition provides a vectorized representation that is a high-level description of the image. The polygons correspond to objects or object parts present in the image. This characterization of radiographs allows the direct application of several shape recognition algorithms to identify objects. In this paper we describe the use of constrained Delaunay triangulations as a uniform foundational tool to achieve multiple visual tasks, namely image segmentation, shape decomposition, and parts-based shape matching. Shape decomposition yields parts that serve as tokens representing local shape characteristics. Parts-based shape matching enables the recognition of objects in the presence of occlusions, which commonly occur in radiographs. The polygonal representation of image features affords the efficient design and application of sophisticated geometric filtering methods to detect large-scale structural properties of objects in images. Finally, the representation of radiographs via polygons results in significant reduction of image file sizes and permits the scalable graphical representation of images, along with annotations of detected objects, in the SVG (scalable vector graphics) format that is proposed by the world wide web consortium (W3C). This is a textual representation that can be compressed and encrypted for efficient and secure transmission of information over wireless channels and on the Internet. In particular, our methods described here provide an algorithmic framework for developing image analysis tools for screening cargo at ports of entry for homeland security.

  19. Identifying murder victims with endodontic radiographs.

    PubMed

    Silva, Rhonan Ferreira; Franco, Ademir; Mendes, Solon Diego Santos Carvalho; Picoli, Fernando Fortes; Nunes, Fernando Gomes; Estrela, Carlos

    2016-01-01

    Endodontics is a special branch of dentistry constantly guided by imaging examinations. From a forensic scope, endodontics plays a valuable role providing solid antemortem (AM) radiographic evidence for comparison with postmortem findings in human identifications. This study illustrates the interface between endodontics and forensic odontology describing three cases of human identification based on radiographic endodontic records. From 2009 to 2012, three unknown male victims of murder were examined in a local Brazilian medico-legal institute to retrieve identity and potential cause of death. Specifically, when asked for AM data, a relative of the three victims provided periapical radiographs of endodontic treatments. Based on that, forensic dentists reproduced the same imaging acquisition techniques obtaining similar periapical radiographs, enabling a comparative dental identification. All the victims were positively identified based on patterns of dental morphology and treatment intervention. This study draws the attention of general and forensic dentists highlight the importance of properly recording dental treatments and searching for evidence in AM endodontic data, respectively.

  20. Identifying murder victims with endodontic radiographs

    PubMed Central

    Silva, Rhonan Ferreira; Franco, Ademir; Mendes, Solon Diego Santos Carvalho; Picoli, Fernando Fortes; Nunes, Fernando Gomes; Estrela, Carlos

    2016-01-01

    Endodontics is a special branch of dentistry constantly guided by imaging examinations. From a forensic scope, endodontics plays a valuable role providing solid antemortem (AM) radiographic evidence for comparison with postmortem findings in human identifications. This study illustrates the interface between endodontics and forensic odontology describing three cases of human identification based on radiographic endodontic records. From 2009 to 2012, three unknown male victims of murder were examined in a local Brazilian medico-legal institute to retrieve identity and potential cause of death. Specifically, when asked for AM data, a relative of the three victims provided periapical radiographs of endodontic treatments. Based on that, forensic dentists reproduced the same imaging acquisition techniques obtaining similar periapical radiographs, enabling a comparative dental identification. All the victims were positively identified based on patterns of dental morphology and treatment intervention. This study draws the attention of general and forensic dentists highlight the importance of properly recording dental treatments and searching for evidence in AM endodontic data, respectively. PMID:28123272

  1. Radiographic applications of spatial frequency multiplexing

    NASA Technical Reports Server (NTRS)

    Macovski, A.

    1981-01-01

    The application of spacial frequency encoding techniques which allow different regions of the X-ray spectrum to be encoded on conventional radiographs was studied. Clinical considerations were reviewed, as were experimental studies involving the encoding and decoding of X-ray images at different energies and the subsequent processing of the data to produce images of specific materials in the body.

  2. TECHNICAL TRAINING FOR INDUSTRIAL RADIOGRAPHERS. FINAL REPORT.

    ERIC Educational Resources Information Center

    BEARDEN, H.D.

    TO OFFSET THE PROBLEM OF A SHORTAGE OF QUALIFIED TECHNICIANS TO SERVE AS RADIOGRAPHERS IN INDUSTRY, 19 STUDENTS WERE TRAINED IN TWO CLASSES, THE FIRST CONSISTING OF 19, AND THE SECOND OF EIGHTEEN 30-HOUR WEEKS. ORGANIZED FORMAL OR LECTURE-TYPE INSTRUCTION WAS PRESENTED IN SOME SUBJECT AREAS, BUT THE MAJOR EMPHASIS WAS ON LABORATORY EXPERIENCES…

  3. The Design of Radiographic Enhancement Systems.

    DTIC Science & Technology

    1986-09-01

    reco Inc., 547 St. Thomas, Longueuil , Quebec, Canada J4H 3A7 9 S. I",, . % . . ,. . - . % % .,, . -.- . . . .d- . - ,. , - - .,, - ,. - ..- , .S...34: the IED safe. Samples of original and enhanced radiographs made with the P-1700 scanner are shown in Figures 5 and 6. The improvement in image

  4. Panoramic radiographic demonstration of bilateral tonsilloliths.

    PubMed

    Guevara, Carlo; Mandel, Louis

    2011-04-01

    Calcifications can develop within the crypts of the palatine tonsil. During routine dental panoramic radiography, these tonsillar calcifications, or tonsilloliths, may be visualized superimposed upon the mandibular ramus. Their anatomic location and radiographic appearance are such that confusion with parotid sialolithiasis may occur. This report defines the symptomatology and differential diagnosis of these tonsilloliths.

  5. Survey of Radiographic Requirements and Techniques.

    ERIC Educational Resources Information Center

    Farman, Allan G.; Shawkat, Abdul H.

    1981-01-01

    A survey of dental schools revealed little standardization of student requirements for dental radiography in the United States. There was a high degree of variability as to what constituted a full radiographic survey, which has implications concerning the maximum limits to patient exposure to radiation. (Author/MLW)

  6. Radiographic evaluation and assessment of paragangliomas.

    PubMed

    Lustrin, E S; Palestro, C; Vaheesan, K

    2001-10-01

    Radiographic imaging plays an important role in the diagnosis and treatment of paragangliomas. Diagnosis and treatment should be performed as a team effort, with all the involved disciplines working together to provide the best possible individualized work-up and treatment plan for the patient.

  7. Radiographic Differentiation of Advanced Fibrocystic Lung Diseases.

    PubMed

    Akira, Masanori

    2017-03-01

    The concept of end-stage lung disease suggests a final common pathway for most diffuse parenchymal lung diseases. In accordance with this concept, end-stage disease is characterized radiographically and pathologically by the presence of extensive honeycombing. However, sequential computed tomographic (CT) scans obtained from patients with chronic diffuse lung disease evolve over time to show various advanced lung disease patterns other than honeycombing. In addition, several radiographically distinct honeycomb patterns, including microcystic, macrocystic, mixed, and combined emphysema and honeycombing, differentiate one advanced lung disease from another. For example, usual interstitial pneumonia (IP) usually shows mixed microcystic and macrocystic honeycombing. In contrast, CT images of long-standing fibrotic nonspecific IP typically show only small, scattered foci of honeycombing; instead, most enlarged airspaces observed in the advanced stage of this disease represent dilatation of bronchioles. In desquamative IP and pulmonary Langerhans cell histiocytosis, focal opacities typically evolve into emphysema-like lesions seen on CT imaging. In combined pulmonary fibrosis and emphysema and sarcoidosis, the cysts tend to be larger than those observed in usual IP. Sequential CT scans in other chronic, diffuse lung diseases also show various distinctive changes. This article highlights radiographic patterns of lung destruction that belie a single common pathway to end-stage lung disease. Recognition of distinct radiographic patterns of lung destruction can help differentiate diffuse parenchymal lung diseases, even in advanced stages of disease evolution.

  8. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1989-03-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculations assume local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  9. MAGNUM2D. Radionuclide Transport Porous Media

    SciTech Connect

    Langford, D.W.; Baca, R.G.

    1988-08-01

    MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculation assumes local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.

  10. Axial Tomography from Digitized Real Time Radiography

    DOE R&D Accomplishments Database

    Zolnay, A. S.; McDonald, W. M.; Doupont, P. A.; McKinney, R. L.; Lee, M. M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  11. Axial tomography from digitized real time radiography

    SciTech Connect

    Zolnay, A.S.; McDonald, W.M.; Doupont, P.A.; McKinney, R.L.; Lee, M.M.

    1985-01-18

    Axial tomography from digitized real time radiographs provides a useful tool for industrial radiography and tomography. The components of this system are: x-ray source, image intensifier, video camera, video line extractor and digitizer, data storage and reconstruction computers. With this system it is possible to view a two dimensional x-ray image in real time at each angle of rotation and select the tomography plane of interest by choosing which video line to digitize. The digitization of a video line requires less than a second making data acquisition relatively short. Further improvements on this system are planned and initial results are reported.

  12. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Hallquist, J. O.; Sanford, Larry

    1996-07-15

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  13. MAZE96. Generates 2D Input for DYNA NIKE & TOPAZ

    SciTech Connect

    Sanford, L.; Hallquist, J.O.

    1992-02-24

    MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.

  14. NIKE2D96. Static & Dynamic Response of 2D Solids

    SciTech Connect

    Raboin, P.; Engelmann, B.; Halquist, J.O.

    1992-01-24

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.

  15. 10 CFR Appendix A to Part 34 - Radiographer Certification

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INDUSTRIAL RADIOGRAPHIC OPERATIONS Pt. 34, App. A Appendix A to Part 34—Radiographer Certification I... Agreement State requirements; 2. Written in a multiple-choice format; 3. Have test items drawn from...

  16. Reliability of Panoramic Radiographs in the Localization of Mandibular Foramen

    PubMed Central

    Patil, Karthikeya; Guledgud, Mahima V

    2015-01-01

    Objective The present study evaluated the reliability and accuracy of panoramic radiographs in the localization of mandibular foramen. Materials and Methods Twenty five Indian dry human adult mandibles constituted the study material. Ten measurements were carried on each of them to evaluate the location of mandibular foramen with respect to adjacent anatomic landmarks. Panoramic radiographs were then made of the mandibles. Same distances were measured on the traced images of the radiographs. Paired t-test and Pearson’s correlation test were applied to evaluate the accuracy and reliability of panoramic radiographs in localization of mandibular foramen. Results The mean distances measured on dry mandibles and panoramic radiographs showed statistically significant difference (p<0.05). There was strong positive correlation between the measurements on dry mandible and panoramic radiographs. Conclusion The panoramic radiographs can serve as a guide in locating the anterosuperior point of mandibular foramen on panoramic radiographs. PMID:26155559

  17. Applicability of Fractal Dimension Analysis in Dental Radiographs for the Evaluation of Renal Osteodystrophy

    NASA Astrophysics Data System (ADS)

    Fernandes, Maurício Anderson; Ribeiro Rosa, Edvaldo Antônio; Johann, Aline Cristina Batista Rodrigues; Grégio, Ana Maria Trindade; Trevilatto, Paula Cristina; Azevedo-Alanis, Luciana Reis

    2016-01-01

    Objectives: To test the capacity of the digital tool, fractal dimension (FD) analysis, in identifying subtle differences in bone pattern in patients with renal osteodystrophy (RO), correlated with the time of hemodialysis, in different regions of interest, delineated on panoramic and periapical radiographs. Study design: A total of 34 patients with chronic renal disease undergoing hemodialysis were submitted to panoramic and periapical radiographs. Different regions of interest were delineated on the mandibular body and ramus. FD was analyzed by means of the software program ImageJ and correlated with the time of hemodialysis. Results: The sample consisted of 34 subjects. The time of hemodialysis varied from 1 to 286 months. There was significant correlation between the time of hemodialysis and the FD values in the region delineated in the mandibular angle (r = 0.498; p = 0.003) and this was shown in the periapical radiographs as well (r = -0.349; p = 0.043). Conclusions: FD analysis was a useful tool in detecting alterations caused by RO in bone pattern, in panoramic and periapical radiographs.

  18. Accuracy of cone beam dental CT, intraoral digital and conventional film radiography for the detection of periapical lesions. An ex vivo study in pig jaws.

    PubMed

    Stavropoulos, Andreas; Wenzel, Ann

    2007-03-01

    To compare the accuracy of cone beam CT scanning (NewTom 3G) with intraoral periapical radiography (Dixi2, Planmeca CCD sensor and Insight film) for the detection of periapical bone defects. Ten frozen pig mandibles were used. All soft tissues were removed and the jaws were sagittally sectioned to obtain three blocks from each side of the jaw containing the premolars and the molars with surrounding jaw bone. All teeth with intact roots were then "extracted". First, 15 blocks were used to define defect size and exposure parameters; then, the remaining 45 blocks were divided into three equal groups. In one group, cylindrical defects of 1 x 1 mm were prepared beyond the apices of the extraction sockets, in another group defects of 2 x 2 mm were similarly prepared, while no defects were prepared in the last group. The teeth were replaced into their sockets and digital and conventional radiographs of all blocks were taken under reproducible conditions. In addition, all blocks were CT scanned with the same volumetric data and then reconstructed to provide sagittal and coronal 2-D sections. Masked evaluation of the images (defect present vs no defect) was performed by four calibrated examiners. Statistical analysis was performed with ANOVA and the significance level was set to P < 0.05. NewTom 3G was statistically significantly better in terms of sensitivity (54%), positive (82.6%) and negative (44.5%) predictive values, and diagnostic accuracy (61%) when compared with digital radiographs (23%, 60%, 31%, 39%), and with conventional ones (28%, 70%, 35%, 44%)-except in the positive predictive value. Specificity was similar for all three methods. No difference was observed between the two periapical (digital vs conventional) radiographs. NewTom 3G may be useful in cases of immediate implants intended to replace teeth with suspicion for possible existing endodontic pathology, or in candidate implant sites neighboring such teeth.

  19. Preliminary evaluation of a high-resolution workstation for diagnostic interpretation of portable radiographs

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Huda, Walter; Palmer, Carole K.; Frost, Meryll M.; Moser, Robert; Staab, Edward V.

    1995-04-01

    A cost effectiveness study on the feasibility of using computed radiography (CR) instead of screen-film methods for portable radiographs indicates that we could only justify CR if film were eliminated. Before purchasing CR equipment, we needed to evaluate the use of softcopy to replace film for routine clinical use. The evaluation had to cover image quality, human factors, and efficiency measures. Screen-film radiographs were digitized and used to simulate CR in two studies. The first study evaluated the quality of digitized images and the workstation user interface. Twenty-one radiographs were selected at random from scopes in the radiology department, were digitized, and transferred to a megascan workstation. Five radiologists were asked to assess the quality of the images and the ease of operation of the workstation while an observer recorded their comments and scores. The second study evaluated the feasibility of using the workstation in a clinical environment. Four radiologists read adult and pediatric portable images in film and softcopy format. Reports were evaluated for differences and timing statistics were kept. The results of the first study indicate that image quality may be acceptable for diagnostic purposes and suggests some changes in the user interface. Newborn infant images were the least acceptable in softcopy, largely due to magnification artifacts introduced when viewing very small images. The evaluation was based on a digitizer as a simulator for a CR unit and the digitizer did not exhibit the same resolution characteristics as CR. Films that were unacceptable from the digitizer are expected to be acceptable with CR. The results of the second study indicated that the high resolution diagnostic workstation could be used in a clinical setting, and that the diagnostic readings were not significantly different between film and softcopy displays. The results also indicated that, depending on the radiologist and the type of images, more time was

  20. Temporal radiographic texture analysis in the detection of periprosthetic osteolysis

    SciTech Connect

    Wilkie, Joel R.; Giger, Maryellen L.; Chinander, Michael R.; Engh, Charles A. Sr.; Hopper, Robert H. Jr.; Martell, John M.

    2008-01-15

    Periprosthetic osteolysis is one of the most serious long-term problems in total hip arthroplasty. It has been primarily attributed to the body's inflammatory response to submicron polyethylene particles worn from the hip implant, and it leads to bone loss and structural deterioration in the surrounding bone. It was previously demonstrated that radiographic texture analysis (RTA) has the ability to distinguish between osteolysis and normal cases at the time of clinical detection of the disease; however, that analysis did not take into account the changes in texture over time. The goal of this preliminary analysis, however, is to assess the ability of temporal radiographic texture analysis (tRTA) to distinguish between patients who develop osteolysis and normal cases. Two tRTA methods were used in the study: the RTA feature change from baseline at various follow-up intervals and the slope of the best-fit line to the RTA data series. These tRTA methods included Fourier-based and fractal-based features calculated from digitized images of 202 total hip replacement cases, including 70 that developed osteolysis. Results show that separation between the osteolysis and normal groups increased over time for the feature difference method, as the disease progressed, with area under the curve (AUC) values from receiver operating characteristic analysis of 0.65 to 0.72 at 15 years postsurgery. Separation for the slope method was also evident, with AUC values ranging from 0.65 to 0.76 for the task of distinguishing between osteolysis and normal cases. The results suggest that tRTA methods have the ability to measure changes in trabecular structure, and may be useful in the early detection of periprosthetic osteolysis.

  1. 21 CFR 892.1970 - Radiographic ECG/respirator synchronizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic ECG/respirator synchronizer. 892.1970... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1970 Radiographic ECG/respirator synchronizer. (a) Identification. A radiographic ECG/respirator synchronizer is a device intended to be used...

  2. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  3. 42 CFR 37.41 - Chest radiograph specifications-film.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Chest radiograph specifications-film. 37.41 Section... Specifications for Performing Chest Radiographic Examinations § 37.41 Chest radiograph specifications—film. (a... posteroanterior projection at full inspiration on a film being no less than 14 by 17 inches and no greater than...

  4. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  5. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  6. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  7. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  8. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  9. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  10. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  11. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  12. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  13. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  14. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  15. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  16. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  17. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  18. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  19. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  20. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  1. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  2. 21 CFR 892.1860 - Radiographic film/cassette changer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film/cassette changer. 892.1860... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1860 Radiographic film/cassette changer. (a) Identification. A radiographic film/cassette changer is a device intended to be used during...

  3. 21 CFR 892.1890 - Radiographic film illuminator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film illuminator. 892.1890 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1890 Radiographic film illuminator. (a) Identification. A radiographic film illuminator is a device containing a visible light source covered with...

  4. 21 CFR 892.1850 - Radiographic film cassette.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Radiographic film cassette. 892.1850 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1850 Radiographic film cassette. (a) Identification. A radiographic film cassette is a device intended for use during diagnostic x-ray procedures...

  5. 21 CFR 892.1900 - Automatic radiographic film processor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automatic radiographic film processor. 892.1900... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1900 Automatic radiographic film processor. (a) Identification. An automatic radiographic film processor is a device intended to be used...

  6. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  7. 21 CFR 892.1640 - Radiographic film marking system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Radiographic film marking system. 892.1640 Section... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1640 Radiographic film marking system. (a) Identification. A radiographic film marking system is a device intended for medical purposes...

  8. Mandibular asymmetry: A proposal of radiographic analysis with public domain software

    PubMed Central

    Lemos, Alexandre Durval; Katz, Cintia Regina Tornisiello; Heimer, Mônica Vilela; Rosenblatt, Aronita

    2014-01-01

    Objective This preliminary study aimed to propose a new analysis of digital panoramic radiographs for a differential diagnosis between functional and morphological mandibular asymmetry in children with and without unilateral posterior crossbite. Methods Analysis is based on linear and angular measurements taken from nine anatomic points, demarcated in sequence directly on digital images. A specific plug-in was developed as part of a larger public domain image processing software (ImageJ) to automate and facilitate measurements. Since panoramic radiographs are typically subject to magnification differences between the right and left sides, horizontal linear measurements were adjusted for greater accuracy in both sides by means of a Distortion Factor (DF). In order to provide a preliminary assessment of proposed analysis and the developed plug-in, radiographs of ten patients (5 with unilateral posterior crossbite and 5 with normal occlusion) were analyzed. Results Considerable divergence was found between the right and left sides in the measurements of mandibular length and position of condyles in patients with unilateral posterior crossbite in comparison to individuals with normal occlusion. Conclusion Although there are more effective and accurate diagnostic methods, panoramic radiography is still widespread, especially in emerging countries. This study presented initial evidence that the proposed analysis can be an important resource for planning early orthodontic intervention and, thus, avoid progression of asymmetries and their consequences. PMID:25162566

  9. No Association between the 2D:4D Fetal Testosterone Marker and Multidimensional Attentional Abilities in Children with ADHD

    ERIC Educational Resources Information Center

    Lemiere, Jurgen; Boets, Bart; Danckaerts, Marina

    2010-01-01

    Aim: It has been suggested that high levels of prenatal testosterone exposure are implied in the aetiology of attention-deficit-hyperactivity disorder (ADHD). This study examined the association between the ratio of the length of the second and fourth digits (2D:4D ratio), a marker of fetal testosterone exposure, and the presence of ADHD-related…

  10. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping

    PubMed Central

    Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea

    2016-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact

  11. CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.

    PubMed

    Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea

    2015-01-01

    TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer

  12. Iterative Reconstruction of Coded Source Neutron Radiographs

    SciTech Connect

    Santos-Villalobos, Hector J; Bingham, Philip R; Gregor, Jens

    2012-01-01

    Use of a coded source facilitates high-resolution neutron imaging but requires that the radiographic data be deconvolved. In this paper, we compare direct deconvolution with two different iterative algorithms, namely, one based on direct deconvolution embedded in an MLE-like framework and one based on a geometric model of the neutron beam and a least squares formulation of the inverse imaging problem.

  13. Video enhancement of dental radiographic films

    SciTech Connect

    Van Dis, M.L.; Beck, F.M.; Miles, D.A. )

    1989-08-01

    A prototype video image display system, a real-time analog enhancer (RAE), was compared to conventional viewing conditions with the use of nonscreen dental films. When medium optical density films were evaluated, there was no significant difference in the number of radiographic details detected. Conventional viewing conditions allowed perception of more details when dark films were evaluated; however, the RAE unit allowed the perception of more details when light films were viewed.

  14. Hand and wrist arthropathies of hemochromatosis and calcium pyrophosphate deposition disease: distinct radiographic features

    SciTech Connect

    Adamson, T.C. III; Resnik, C.S.; Guerra, J. Jr.; Vint, V.C.; Weisman, M.H.; Resnick, D.

    1983-05-01

    Radiographic features of hand and wrist involvement in 26 patients with hemochromatosis and in 26 patients with idiopathic calcium pyrophosphate dihydrate (CPPD) crystal deposition disease were compared. Two radiologists independently examined the radiographs without knowledge of the specific group to which the patient belonged. The results of this study clearly establish that structural joint diseases in the two disorders are not identical. Characteristic findings allow the radiologist to favor one diagnosis over the other. These radiograhic differences indicate that the arthropathy of hemochromatosis is related to factors additional to the presence of CPPD crystals, specifically, the more prevalent narrowing of the metacarpophalangeal joint spaces, including those in the fourth and fifth digits, peculiar hook-like osteophytes on the radial aspect of the metacarpal heads, and less prevalent separation of the scaphoid and the lunate.

  15. Clinical and radiographic maxillofacial features of pycnodysostosis

    PubMed Central

    Alves, Nilton; Cantín, Mario

    2014-01-01

    The aim of this study was to review of the literature to determine the radiographic and clinical maxillofacial features of pycnodysostosis emphasizing the main aspects of interest to the dentist in order to make them fit for the proper treatment of this population. It is important to make the diagnosis as early as possible in order to plan the treatment more suitable to provide a better life’s quality to the patients. The most frequent clinical maxillofacial features were: grooved palate, midfacial hypoplasia, mandibular hypoplasia and enamel hypoplasia. The most common radiographic maxillofacial features were: obtuse mandibular angle, frontal/parietal/occiptal bossing, open fontanels and sutures, multiple impacted teeth. The earlier diagnostic of pycnodysostosis has a fundamental role in general health of the patients. We consider that is very important that the dentist know recognize the radiographic and clinical maxillofacial features of pycnodysostosis, which allows correct treatment planning avoiding risks and ensuring better life’s quality to the patients. PMID:24753741

  16. Unsupervised segmentation of lungs from chest radiographs

    NASA Astrophysics Data System (ADS)

    Ghosh, Payel; Antani, Sameer K.; Long, L. Rodney; Thoma, George R.

    2012-03-01

    This paper describes our preliminary investigations for deriving and characterizing coarse-level textural regions present in the lung field on chest radiographs using unsupervised grow-cut (UGC), a cellular automaton based unsupervised segmentation technique. The segmentation has been performed on a publicly available data set of chest radiographs. The algorithm is useful for this application because it automatically converges to a natural segmentation of the image from random seed points using low-level image features such as pixel intensity values and texture features. Our goal is to develop a portable screening system for early detection of lung diseases for use in remote areas in developing countries. This involves developing automated algorithms for screening x-rays as normal/abnormal with a high degree of sensitivity, and identifying lung disease patterns on chest x-rays. Automatically deriving and quantitatively characterizing abnormal regions present in the lung field is the first step toward this goal. Therefore, region-based features such as geometrical and pixel-value measurements were derived from the segmented lung fields. In the future, feature selection and classification will be performed to identify pathological conditions such as pulmonary tuberculosis on chest radiographs. Shape-based features will also be incorporated to account for occlusions of the lung field and by other anatomical structures such as the heart and diaphragm.

  17. Residual lens effects in 2D mode of auto-stereoscopic lenticular-based switchable 2D/3D displays

    NASA Astrophysics Data System (ADS)

    Sluijter, M.; IJzerman, W. L.; de Boer, D. K. G.; de Zwart, S. T.

    2006-04-01

    We discuss residual lens effects in multi-view switchable auto-stereoscopic lenticular-based 2D/3D displays. With the introduction of a switchable lenticular, it is possible to switch between a 2D mode and a 3D mode. The 2D mode displays conventional content, whereas the 3D mode provides the sensation of depth to the viewer. The uniformity of a display in the 2D mode is quantified by the quality parameter modulation depth. In order to reduce the modulation depth in the 2D mode, birefringent lens plates are investigated analytically and numerically, by ray tracing. We can conclude that the modulation depth in the 2D mode can be substantially decreased by using birefringent lens plates with a perfect index match between lens material and lens plate. Birefringent lens plates do not disturb the 3D performance of a switchable 2D/3D display.

  18. Osteology and radiographic anatomy of the pelvis and hind limb of healthy ring-tailed lemurs (Lemur catta).

    PubMed

    Makungu, M; Groenewald, H B; du Plessis, W M; Barrows, M; Koeppel, K N

    2014-06-01

    In family Lemuridae, anatomical variations exist. Considering its conservation status (near threatened) and presence of similarities between strepsirrhines and primitive animals, it was thought to be beneficial to describe the gross osteology and radiographic anatomy of the pelvis and hind limb of ring-tailed lemurs (Lemur catta) as a reference for clinical use and species identification. Radiography was performed in 14 captive adult ring-tailed lemurs. The radiographic findings were correlated with bone specimens from two adult animals. Additionally, computed tomography of the hind limbs was performed in one animal. The pelvic bone has a well-developed caudal ventral iliac spine. The patella has a prominent tuberosity on the cranial surface. The first metatarsal bone and digit 1 are markedly stouter than the other metatarsal bones and digits with medial divergence from the rest of the metatarsal bones and digits. Ossicles were seen in the lateral meniscus, inter-phalangeal joint of digit 1 and in the infrapatellar fat pad. Areas of mineral opacity were seen within the external genitalia, which are believed to be the os penis and os clitoris. Variations exist in the normal osteology and radiographic appearance of the pelvis and hind limb of different animal species. The use of only atlases from domestic cats and dogs for interpretative purposes may be misleading.

  19. Differential CYP 2D6 metabolism alters primaquine pharmacokinetics.

    PubMed

    Potter, Brittney M J; Xie, Lisa H; Vuong, Chau; Zhang, Jing; Zhang, Ping; Duan, Dehui; Luong, Thu-Lan T; Bandara Herath, H M T; Dhammika Nanayakkara, N P; Tekwani, Babu L; Walker, Larry A; Nolan, Christina K; Sciotti, Richard J; Zottig, Victor E; Smith, Philip L; Paris, Robert M; Read, Lisa T; Li, Qigui; Pybus, Brandon S; Sousa, Jason C; Reichard, Gregory A; Marcsisin, Sean R

    2015-04-01

    Primaquine (PQ) metabolism by the cytochrome P450 (CYP) 2D family of enzymes is required for antimalarial activity in both humans (2D6) and mice (2D). Human CYP 2D6 is highly polymorphic, and decreased CYP 2D6 enzyme activity has been linked to decreased PQ antimalarial activity. Despite the importance of CYP 2D metabolism in PQ efficacy, the exact role that these enzymes play in PQ metabolism and pharmacokinetics has not been extensively studied in vivo. In this study, a series of PQ pharmacokinetic experiments were conducted in mice with differential CYP 2D metabolism characteristics, including wild-type (WT), CYP 2D knockout (KO), and humanized CYP 2D6 (KO/knock-in [KO/KI]) mice. Plasma and liver pharmacokinetic profiles from a single PQ dose (20 mg/kg of body weight) differed significantly among the strains for PQ and carboxy-PQ. Additionally, due to the suspected role of phenolic metabolites in PQ efficacy, these were probed using reference standards. Levels of phenolic metabolites were highest in mice capable of metabolizing CYP 2D6 substrates (WT and KO/KI 2D6 mice). PQ phenolic metabolites were present in different quantities in the two strains, illustrating species-specific differences in PQ metabolism between the human and mouse enzymes. Taking the data together, this report furthers understanding of PQ pharmacokinetics in the context of differential CYP 2D metabolism and has important implications for PQ administration in humans with different levels of CYP 2D6 enzyme activity.

  20. The forensic radiographer: a new member in the medicolegal team.

    PubMed

    Schneider, Benjamin; Chevallier, Christine; Dominguez, Alejandro; Bruguier, Christine; Elandoy, Cristèle; Mangin, Patrice; Grabherr, Silke

    2012-03-01

    Multidetector computed tomography is becoming more widespread in forensic medicine. In most services, autopsy assistants perform the radiological examination. We introduced professional radiographers into the legal medicine service and hypothesized they would also be able to take over duties currently reserved for other specialists. The aims of this study were to evaluate if radiographers could be trained as "forensic radiographers" by (1) integrating graduated medical radiographers into the legal medicine service, (2) investigating the advantages of this collaboration, and (3) defining the duties of the forensic radiographers.The study was performed prospectively on a group of 8 recruited radiographers who underwent a testing period with special training. They learned the basics of medicolegal case treatment, the autonomous execution of postmortem computed tomography angiography, and postprocessing of data. Seven of 8 radiographers finished the training and were integrated into our service. Although all radiographers were able to fulfill the duties demanded after the training period, some radiographers could not enter or complete the program because they were unable to work with dead bodies.Our study presents the advantages of integrating radiographers into the medicolegal team and proposes how to train the forensic radiographers. In addition, the duties and responsibilities of these new specialists are defined.

  1. Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials

    NASA Technical Reports Server (NTRS)

    Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.

    1993-01-01

    Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.

  2. Known-component 3D-2D registration for quality assurance of spine surgery pedicle screw placement

    PubMed Central

    Uneri, A; De Silva, T; Stayman, JW; Kleinszig, G; Vogt, S; Khanna, AJ; Gokaslan, ZL; Wolinsky, J-P; Siewerdsen, JH

    2015-01-01

    Purpose A 3D-2D image registration method is presented that exploits knowledge of interventional devices (e.g., K-wires or spine screws – referred to as “known components”) to extend the functionality of intraoperative radiography/fluoroscopy by providing quantitative measurement and quality assurance (QA) of the surgical product. Methods The known-component registration (KC-Reg) algorithm uses robust 3D-2D registration combined with 3D component models of surgical devices known to be present in intraoperative 2D radiographs. Component models were investigated that vary in fidelity from simple parametric models (e.g., approximation of a screw as a simple cylinder, referred to as “parametrically-known” component [pKC] registration) to precise models based on device-specific CAD drawings (referred to as “exactly-known” component [eKC] registration). 3D-2D registration from three intraoperative radiographs was solved using the covariance matrix adaptation evolution strategy (CMA-ES) to maximize image-gradient similarity, relating device placement relative to 3D preoperative CT of the patient. Spine phantom and cadaver studies were conducted to evaluate registration accuracy and demonstrate QA of the surgical product by verification of the type of devices delivered and conformance within the “acceptance window” of the spinal pedicle. Results Pedicle screws were successfully registered to radiographs acquired from a mobile C-arm, providing TRE 1–4 mm and <5° using simple parametric (pKC) models, further improved to <1 mm and <1° using eKC registration. Using advanced pKC models, screws that did not match the device models specified in the surgical plan were detected with an accuracy of >99%. Visualization of registered devices relative to surgical planning and the pedicle acceptance window provided potentially valuable QA of the surgical product and reliable detection of pedicle screw breach. Conclusions 3D-2D registration combined with 3D models

  3. Known-component 3D-2D registration for quality assurance of spine surgery pedicle screw placement.

    PubMed

    Uneri, A; De Silva, T; Stayman, J W; Kleinszig, G; Vogt, S; Khanna, A J; Gokaslan, Z L; Wolinsky, J-P; Siewerdsen, J H

    2015-10-21

    A 3D-2D image registration method is presented that exploits knowledge of interventional devices (e.g. K-wires or spine screws-referred to as 'known components') to extend the functionality of intraoperative radiography/fluoroscopy by providing quantitative measurement and quality assurance (QA) of the surgical product. The known-component registration (KC-Reg) algorithm uses robust 3D-2D registration combined with 3D component models of surgical devices known to be present in intraoperative 2D radiographs. Component models were investigated that vary in fidelity from simple parametric models (e.g. approximation of a screw as a simple cylinder, referred to as 'parametrically-known' component [pKC] registration) to precise models based on device-specific CAD drawings (referred to as 'exactly-known' component [eKC] registration). 3D-2D registration from three intraoperative radiographs was solved using the covariance matrix adaptation evolution strategy (CMA-ES) to maximize image-gradient similarity, relating device placement relative to 3D preoperative CT of the patient. Spine phantom and cadaver studies were conducted to evaluate registration accuracy and demonstrate QA of the surgical product by verification of the type of devices delivered and conformance within the 'acceptance window' of the spinal pedicle. Pedicle screws were successfully registered to radiographs acquired from a mobile C-arm, providing TRE 1-4 mm and  <5° using simple parametric (pKC) models, further improved to  <1 mm and  <1° using eKC registration. Using advanced pKC models, screws that did not match the device models specified in the surgical plan were detected with an accuracy of  >99%. Visualization of registered devices relative to surgical planning and the pedicle acceptance window provided potentially valuable QA of the surgical product and reliable detection of pedicle screw breach. 3D-2D registration combined with 3D models of known surgical devices offers a

  4. Known-component 3D-2D registration for quality assurance of spine surgery pedicle screw placement

    NASA Astrophysics Data System (ADS)

    Uneri, A.; De Silva, T.; Stayman, J. W.; Kleinszig, G.; Vogt, S.; Khanna, A. J.; Gokaslan, Z. L.; Wolinsky, J.-P.; Siewerdsen, J. H.

    2015-10-01

    A 3D-2D image registration method is presented that exploits knowledge of interventional devices (e.g. K-wires or spine screws—referred to as ‘known components’) to extend the functionality of intraoperative radiography/fluoroscopy by providing quantitative measurement and quality assurance (QA) of the surgical product. The known-component registration (KC-Reg) algorithm uses robust 3D-2D registration combined with 3D component models of surgical devices known to be present in intraoperative 2D radiographs. Component models were investigated that vary in fidelity from simple parametric models (e.g. approximation of a screw as a simple cylinder, referred to as ‘parametrically-known’ component [pKC] registration) to precise models based on device-specific CAD drawings (referred to as ‘exactly-known’ component [eKC] registration). 3D-2D registration from three intraoperative radiographs was solved using the covariance matrix adaptation evolution strategy (CMA-ES) to maximize image-gradient similarity, relating device placement relative to 3D preoperative CT of the patient. Spine phantom and cadaver studies were conducted to evaluate registration accuracy and demonstrate QA of the surgical product by verification of the type of devices delivered and conformance within the ‘acceptance window’ of the spinal pedicle. Pedicle screws were successfully registered to radiographs acquired from a mobile C-arm, providing TRE 1-4 mm and  <5° using simple parametric (pKC) models, further improved to  <1 mm and  <1° using eKC registration. Using advanced pKC models, screws that did not match the device models specified in the surgical plan were detected with an accuracy of  >99%. Visualization of registered devices relative to surgical planning and the pedicle acceptance window provided potentially valuable QA of the surgical product and reliable detection of pedicle screw breach. 3D-2D registration combined with 3D models of known surgical

  5. The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China

    PubMed Central

    Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian

    2016-01-01

    The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology. PMID:27375513

  6. The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China.

    PubMed

    Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian

    2016-01-01

    The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology.

  7. Improved 2D/3D registration robustness using local spatial information

    NASA Astrophysics Data System (ADS)

    De Momi, Elena; Eckman, Kort; Jaramaz, Branislav; DiGioia, Anthony, III

    2006-03-01

    Xalign is a tool designed to measure implant orientation after joint arthroplasty by co-registering a projection of an implant model and a digitally reconstructed radiograph of the patient's anatomy with a post operative x-ray. A mutual information based registration method is used to automate alignment. When using basic mutual information, the presence of local maxima can result in misregistration. To increase robustness of registration, our research is aimed at improving the similarity function by modifying the information measure and incorporating local spatial information. A test dataset with known groundtruth parameters was created to evaluate the performance of this measure. A synthetic radiograph was generated first from a preoperative pelvic CT scan to act as the gold standard. The voxel weights used to generate the image were then modified and new images were generated with the CT rigidly transformed. The roll, pitch and yaw angles span a range of -10/+10 degrees, while x, y and z translations range from -10mm to +10mm. These images were compared with the reference image. The proposed cost function correctly identified the correct pose in all tests and did not exhibit any local maxima which would slow or prevent locating the global maximum.

  8. Computational Screening of 2D Materials for Photocatalysis.

    PubMed

    Singh, Arunima K; Mathew, Kiran; Zhuang, Houlong L; Hennig, Richard G

    2015-03-19

    Two-dimensional (2D) materials exhibit a range of extraordinary electronic, optical, and mechanical properties different from their bulk counterparts with potential applications for 2D materials emerging in energy storage and conversion technologies. In this Perspective, we summarize the recent developments in the field of solar water splitting using 2D materials and review a computational screening approach to rapidly and efficiently discover more 2D materials that possess properties suitable for solar water splitting. Computational tools based on density-functional theory can predict the intrinsic properties of potential photocatalyst such as their electronic properties, optical absorbance, and solubility in aqueous solutions. Computational tools enable the exploration of possible routes to enhance the photocatalytic activity of 2D materials by use of mechanical strain, bias potential, doping, and pH. We discuss future research directions and needed method developments for the computational design and optimization of 2D materials for photocatalysis.

  9. Self-Calibration of Cone-Beam CT Geometry Using 3D-2D Image Registration: Development and Application to Task-Based Imaging with a Robotic C-Arm

    PubMed Central

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

    2015-01-01

    Purpose Robotic C-arm systems are capable of general noncircular orbits whose trajectories can be driven by the particular imaging task. However obtaining accurate calibrations for reconstruction in such geometries can be a challenging problem. This work proposes a method to perform a unique geometric calibration of an arbitrary C-arm orbit by registering 2D projections to a previously acquired 3D image to determine the transformation parameters representing the system geometry. Methods Experiments involved a cone-beam CT (CBCT) bench system, a robotic C-arm, and three phantoms. A robust 3D-2D registration process was used to compute the 9 degree of freedom (DOF) transformation between each projection and an existing 3D image by maximizing normalized gradient information with a digitally reconstructed radiograph (DRR) of the 3D volume. The quality of the resulting “self-calibration” was evaluated in terms of the agreement with an established calibration method using a BB phantom as well as image quality in the resulting CBCT reconstruction. Results The self-calibration yielded CBCT images without significant difference in spatial resolution from the standard (“true”) calibration methods (p-value >0.05 for all three phantoms), and the differences between CBCT images reconstructed using the “self” and “true” calibration methods were on the order of 10−3 mm−1. Maximum error in magnification was 3.2%, and back-projection ray placement was within 0.5 mm. Conclusion The proposed geometric “self” calibration provides a means for 3D imaging on general non-circular orbits in CBCT systems for which a geometric calibration is either not available or not reproducible. The method forms the basis of advanced “task-based” 3D imaging methods now in development for robotic C-arms. PMID:26388661

  10. Self-calibration of cone-beam CT geometry using 3D-2D image registration: development and application to tasked-based imaging with a robotic C-arm

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Purpose: Robotic C-arm systems are capable of general noncircular orbits whose trajectories can be driven by the particular imaging task. However obtaining accurate calibrations for reconstruction in such geometries can be a challenging problem. This work proposes a method to perform a unique geometric calibration of an arbitrary C-arm orbit by registering 2D projections to a previously acquired 3D image to determine the transformation parameters representing the system geometry. Methods: Experiments involved a cone-beam CT (CBCT) bench system, a robotic C-arm, and three phantoms. A robust 3D-2D registration process was used to compute the 9 degree of freedom (DOF) transformation between each projection and an existing 3D image by maximizing normalized gradient information with a digitally reconstructed radiograph (DRR) of the 3D volume. The quality of the resulting "self-calibration" was evaluated in terms of the agreement with an established calibration method using a BB phantom as well as image quality in the resulting CBCT reconstruction. Results: The self-calibration yielded CBCT images without significant difference in spatial resolution from the standard ("true") calibration methods (p-value >0.05 for all three phantoms), and the differences between CBCT images reconstructed using the "self" and "true" calibration methods were on the order of 10-3 mm-1. Maximum error in magnification was 3.2%, and back-projection ray placement was within 0.5 mm. Conclusion: The proposed geometric "self" calibration provides a means for 3D imaging on general noncircular orbits in CBCT systems for which a geometric calibration is either not available or not reproducible. The method forms the basis of advanced "task-based" 3D imaging methods now in development for robotic C-arms.

  11. Synthetic Covalent and Non-Covalent 2D Materials.

    PubMed

    Boott, Charlotte E; Nazemi, Ali; Manners, Ian

    2015-11-16

    The creation of synthetic 2D materials represents an attractive challenge that is ultimately driven by their prospective uses in, for example, electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration. This Review illustrates some recent advances in this diverse field with a focus on covalent and non-covalent 2D polymers and frameworks, and self-assembled 2D materials derived from nanoparticles, homopolymers, and block copolymers.

  12. 2D:4D Asymmetry and Gender Differences in Academic Performance

    PubMed Central

    Nye, John V. C.; Androuschak, Gregory; Desierto, Desirée; Jones, Garett; Yudkevich, Maria

    2012-01-01

    Exposure to prenatal androgens affects both future behavior and life choices. However, there is still relatively limited evidence on its effects on academic performance. Moreover, the predicted effect of exposure to prenatal testosterone (T)–which is inversely correlated with the relative length of the second to fourth finger lengths (2D:4D)–would seem to have ambiguous effects on academic achievement since traits like aggressiveness or risk-taking are not uniformly positive for success in school. We provide the first evidence of a non-linear, quadratic, relationship between 2D:4D and academic achievement using samples from Moscow and Manila. We also find that there is a gender differentiated link between various measures of academic achievement and measured digit ratios. These effects are different depending on the field of study, choice of achievement measure, and use of the right hand or left digit ratios. The results seem to be asymmetric between Moscow and Manila where the right (left) hand generates inverted-U (U-shaped) curves in Moscow while the pattern for hands reverses in Manila. Drawing from unusually large and detailed samples of university students in two countries not studied in the digit literature, our work is the first to have a large cross country comparison that includes two groups with very different ethnic compositions. PMID:23056282

  13. 2D:4D asymmetry and gender differences in academic performance.

    PubMed

    Nye, John V C; Androuschak, Gregory; Desierto, Desirée; Jones, Garett; Yudkevich, Maria

    2012-01-01

    Exposure to prenatal androgens affects both future behavior and life choices. However, there is still relatively limited evidence on its effects on academic performance. Moreover, the predicted effect of exposure to prenatal testosterone (T)-which is inversely correlated with the relative length of the second to fourth finger lengths (2D:4D)-would seem to have ambiguous effects on academic achievement since traits like aggressiveness or risk-taking are not uniformly positive for success in school. We provide the first evidence of a non-linear, quadratic, relationship between 2D:4D and academic achievement using samples from Moscow and Manila. We also find that there is a gender differentiated link between various measures of academic achievement and measured digit ratios. These effects are different depending on the field of study, choice of achievement measure, and use of the right hand or left digit ratios. The results seem to be asymmetric between Moscow and Manila where the right (left) hand generates inverted-U (U-shaped) curves in Moscow while the pattern for hands reverses in Manila. Drawing from unusually large and detailed samples of university students in two countries not studied in the digit literature, our work is the first to have a large cross country comparison that includes two groups with very different ethnic compositions.

  14. Registration of MRI to intraoperative radiographs for target localization in spinal interventions

    NASA Astrophysics Data System (ADS)

    De Silva, T.; Uneri, A.; Ketcha, M. D.; Reaungamornrat, S.; Goerres, J.; Jacobson, M. W.; Vogt, S.; Kleinszig, G.; Khanna, A. J.; Wolinsky, J.-P.; Siewerdsen, J. H.

    2017-01-01

    Decision support to assist in target vertebra localization could provide a useful aid to safe and effective spine surgery. Previous solutions have shown 3D-2D registration of preoperative CT to intraoperative radiographs to reliably annotate vertebral labels for assistance during level localization. We present an algorithm (referred to as MR-LevelCheck) to perform 3D-2D registration based on a preoperative MRI to accommodate the increasingly common clinical scenario in which MRI is used instead of CT for preoperative planning. Straightforward adaptation of gradient/intensity-based methods appropriate to CT-to-radiograph registration is confounded by large mismatch and noncorrespondence in image intensity between MRI and radiographs. The proposed method overcomes such challenges with a simple vertebrae segmentation step using vertebra centroids as seed points (automatically defined within existing workflow). Forwards projections are computed using segmented MRI and registered to radiographs via gradient orientation (GO) similarity and the CMA-ES (covariance-matrix-adaptation evolutionary-strategy) optimizer. The method was tested in an IRB-approved study involving 10 patients undergoing cervical, thoracic, or lumbar spine surgery following preoperative MRI. The method successfully registered each preoperative MRI to intraoperative radiographs and maintained desirable properties of robustness against image content mismatch and large capture range. Robust registration performance was achieved with projection distance error (PDE) (median  ±  IQR)  =  4.3  ±  2.6 mm (median  ±  IQR) and 0% failure rate. Segmentation accuracy for the continuous max-flow method yielded dice coefficient  =  88.1  ±  5.2, accuracy  =  90.6  ±  5.7, RMSE  =  1.8  ±  0.6 mm, and contour affinity ratio (CAR)  =  0.82  ±  0.08. Registration performance was found to be robust for

  15. Registration of MRI to intraoperative radiographs for target localization in spinal interventions.

    PubMed

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

    2017-01-21

    Decision support to assist in target vertebra localization could provide a useful aid to safe and effective spine surgery. Previous solutions have shown 3D-2D registration of preoperative CT to intraoperative radiographs to reliably annotate vertebral labels for assistance during level localization. We present an algorithm (referred to as MR-LevelCheck) to perform 3D-2D registration based on a preoperative MRI to accommodate the increasingly common clinical scenario in which MRI is used instead of CT for preoperative planning. Straightforward adaptation of gradient/intensity-based methods appropriate to CT-to-radiograph registration is confounded by large mismatch and noncorrespondence in image intensity between MRI and radiographs. The proposed method overcomes such challenges with a simple vertebrae segmentation step using vertebra centroids as seed points (automatically defined within existing workflow). Forwards projections are computed using segmented MRI and registered to radiographs via gradient orientation (GO) similarity and the CMA-ES (covariance-matrix-adaptation evolutionary-strategy) optimizer. The method was tested in an IRB-approved study involving 10 patients undergoing cervical, thoracic, or lumbar spine surgery following preoperative MRI. The method successfully registered each preoperative MRI to intraoperative radiographs and maintained desirable properties of robustness against image content mismatch and large capture range. Robust registration performance was achieved with projection distance error (PDE) (median  ±  IQR)  =  4.3  ±  2.6 mm (median  ±  IQR) and 0% failure rate. Segmentation accuracy for the continuous max-flow method yielded dice coefficient  =  88.1  ±  5.2, accuracy  =  90.6  ±  5.7, RMSE  =  1.8  ±  0.6 mm, and contour affinity ratio (CAR)  =  0.82  ±  0.08. Registration performance was found to be robust for

  16. Epitaxial 2D SnSe2/ 2D WSe2 van der Waals Heterostructures.

    PubMed

    Aretouli, Kleopatra Emmanouil; Tsoutsou, Dimitra; Tsipas, Polychronis; Marquez-Velasco, Jose; Aminalragia Giamini, Sigiava; Kelaidis, Nicolaos; Psycharis, Vassilis; Dimoulas, Athanasios

    2016-09-07

    van der Waals heterostructures of 2D semiconductor materials can be used to realize a number of (opto)electronic devices including tunneling field effect devices (TFETs). It is shown in this work that high quality SnSe2/WSe2 vdW heterostructure can be grown by molecular beam epitaxy on AlN(0001)/Si(111) substrates using a Bi2Se3 buffer layer. A valence band offset of 0.8 eV matches the energy gap of SnSe2 in such a way that the VB edge of WSe2 and the CB edge of SnSe2 are lined up, making this materials combination suitable f