WorldWideScience

Sample records for volume 3d fast

  1. 3D Volume Rendering and 3D Printing (Additive Manufacturing).

    Science.gov (United States)

    Katkar, Rujuta A; Taft, Robert M; Grant, Gerald T

    2018-07-01

    Three-dimensional (3D) volume-rendered images allow 3D insight into the anatomy, facilitating surgical treatment planning and teaching. 3D printing, additive manufacturing, and rapid prototyping techniques are being used with satisfactory accuracy, mostly for diagnosis and surgical planning, followed by direct manufacture of implantable devices. The major limitation is the time and money spent generating 3D objects. Printer type, material, and build thickness are known to influence the accuracy of printed models. In implant dentistry, the use of 3D-printed surgical guides is strongly recommended to facilitate planning and reduce risk of operative complications. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. When fast atom diffraction turns 3D

    International Nuclear Information System (INIS)

    Zugarramurdi, Asier; Borisov, Andrei G.

    2013-01-01

    Fast atom diffraction at surfaces (FAD) in grazing incidence geometry is characterized by the slow motion in the direction perpendicular to the surface and fast motion parallel to the surface plane along a low index direction. It is established experimentally that for the typical surfaces the FAD reveals the 2D diffraction patterns associated with exchange of the reciprocal lattice vector perpendicular to the direction of fast motion. The reciprocal lattice vector exchange along the direction of fast motion is negligible. The usual approximation made in the description of the experimental data is then to assume that the effective potential leading to the diffraction results from the averaging of the 3D surface potential along the atomic strings forming the axial channel. In this work we use full quantum wave packet propagation calculations to study theoretically the possibility to observe the 3D diffraction in FAD experiments. We show that for the surfaces with large unit cell, such as can be the case for reconstructed or vicinal surfaces, the 3D diffraction can be observed. The reciprocal lattice vector exchange along the direction of fast motion leads to several Laue circles in the diffraction pattern

  3. Multichannel algorithm for fast 3D reconstruction

    International Nuclear Information System (INIS)

    Rodet, Thomas; Grangeat, Pierre; Desbat, Laurent

    2002-01-01

    Some recent medical imaging applications such as functional imaging (PET and SPECT) or interventional imaging (CT fluoroscopy) involve increasing amounts of data. In order to reduce the image reconstruction time, we develop a new fast 3D reconstruction algorithm based on a divide and conquer approach. The proposed multichannel algorithm performs an indirect frequential subband decomposition of the image f to be reconstructed (f=Σf j ) through the filtering of the projections Rf. The subband images f j are reconstructed on a downsampled grid without information suppression. In order to reduce the computation time, we do not backproject the null filtered projections and we downsample the number of projections according to the Shannon conditions associated with the subband image. Our algorithm is based on filtering and backprojection operators. Using the same algorithms for these basic operators, our approach is three and a half times faster than a classical FBP algorithm for a 2D image 512x512 and six times faster for a 3D image 32x512x512. (author)

  4. Lightning fast animation in Element 3D

    CERN Document Server

    Audronis, Ty

    2014-01-01

    An easy-to-follow and all-inclusive guide, in which the underlying principles of 3D animation as well as their importance are explained in detail. The lessons are designed to teach you how to think of 3D animation in such a way that you can troubleshoot any problem, or animate any scene that comes your way.If you are a Digital Artist, Animation Artist, or a Game Programmer and you want to become an expert in Element 3D, this is the book for you. Although there are a lot of basics for beginners in this book, it includes some advanced techniques for both animating in Element 3D, and overcoming i

  5. Fast Segmentation From Blurred Data in 3D Fluorescence Microscopy.

    Science.gov (United States)

    Storath, Martin; Rickert, Dennis; Unser, Michael; Weinmann, Andreas

    2017-10-01

    We develop a fast algorithm for segmenting 3D images from linear measurements based on the Potts model (or piecewise constant Mumford-Shah model). To that end, we first derive suitable space discretizations of the 3D Potts model, which are capable of dealing with 3D images defined on non-cubic grids. Our discretization allows us to utilize a specific splitting approach, which results in decoupled subproblems of moderate size. The crucial point in the 3D setup is that the number of independent subproblems is so large that we can reasonably exploit the parallel processing capabilities of the graphics processing units (GPUs). Our GPU implementation is up to 18 times faster than the sequential CPU version. This allows to process even large volumes in acceptable runtimes. As a further contribution, we extend the algorithm in order to deal with non-negativity constraints. We demonstrate the efficiency of our method for combined image deconvolution and segmentation on simulated data and on real 3D wide field fluorescence microscopy data.

  6. Measurement of CSF volume with 3D-FASE MRI

    International Nuclear Information System (INIS)

    Kanayama, Shoichi; Calderon, A.; Makita, Jun-ichi; Ohara, Yukou; Tsunoda, Akira; Sato, Kiyoshi.

    1997-01-01

    A noninvasive and fast cerebrospinal fluid (CSF) volume measurement method has been developed using 3D-FASE MRI and a semi-automatic segmentation process. Images with a high CSF/(gray and white matter) ratio (about 10-20) were obtained with a heavily T 2 weighted 3D-FASE sequence. The CSF region was segmented with a region growing method and the volume was calculated from the number of segmented voxels with a signal intensity weighted summation. Total measurement time was about 30 minutes for each study. The errors of the measured volumes were within 10% for the phantom experiments. Intracranial CSF volumes of normal volunteers ranged between about 100 and 200 cc and the ventricle/intracranial CSF ratio was about 10%. 3D display of the segmented intracranial and ventricle CSF regions was also carried out and proved to be useful to understand the anatomy. Increased intracranial and/or ventricle CSF volumes were obtained for a hydrocephalic patient and one patient with probable cerebral atrophy. The results suggest that the developed method could be used for the diagnosis of patients with neurological diseases. (author)

  7. 3D pulmonary nodules detection using fast marching segmentation ...

    African Journals Online (AJOL)

    This paper proposes an automated computer aided diagnosis system for detection of pulmonary nodules based on three dimensional (3D) structures. Lung ... The proposed detection methodology can give the accuracy of 92%. Keywords: lung cancer; pulmonary nodule; fast marching; 3D features; random forest classifier.

  8. MRI Volume Fusion Based on 3D Shearlet Decompositions.

    Science.gov (United States)

    Duan, Chang; Wang, Shuai; Wang, Xue Gang; Huang, Qi Hong

    2014-01-01

    Nowadays many MRI scans can give 3D volume data with different contrasts, but the observers may want to view various contrasts in the same 3D volume. The conventional 2D medical fusion methods can only fuse the 3D volume data layer by layer, which may lead to the loss of interframe correlative information. In this paper, a novel 3D medical volume fusion method based on 3D band limited shearlet transform (3D BLST) is proposed. And this method is evaluated upon MRI T2* and quantitative susceptibility mapping data of 4 human brains. Both the perspective impression and the quality indices indicate that the proposed method has a better performance than conventional 2D wavelet, DT CWT, and 3D wavelet, DT CWT based fusion methods.

  9. MRI Volume Fusion Based on 3D Shearlet Decompositions

    Directory of Open Access Journals (Sweden)

    Chang Duan

    2014-01-01

    Full Text Available Nowadays many MRI scans can give 3D volume data with different contrasts, but the observers may want to view various contrasts in the same 3D volume. The conventional 2D medical fusion methods can only fuse the 3D volume data layer by layer, which may lead to the loss of interframe correlative information. In this paper, a novel 3D medical volume fusion method based on 3D band limited shearlet transform (3D BLST is proposed. And this method is evaluated upon MRI T2* and quantitative susceptibility mapping data of 4 human brains. Both the perspective impression and the quality indices indicate that the proposed method has a better performance than conventional 2D wavelet, DT CWT, and 3D wavelet, DT CWT based fusion methods.

  10. Overview of fast algorithm in 3D dynamic holographic display

    Science.gov (United States)

    Liu, Juan; Jia, Jia; Pan, Yijie; Wang, Yongtian

    2013-08-01

    3D dynamic holographic display is one of the most attractive techniques for achieving real 3D vision with full depth cue without any extra devices. However, huge 3D information and data should be preceded and be computed in real time for generating the hologram in 3D dynamic holographic display, and it is a challenge even for the most advanced computer. Many fast algorithms are proposed for speeding the calculation and reducing the memory usage, such as:look-up table (LUT), compressed look-up table (C-LUT), split look-up table (S-LUT), and novel look-up table (N-LUT) based on the point-based method, and full analytical polygon-based methods, one-step polygon-based method based on the polygon-based method. In this presentation, we overview various fast algorithms based on the point-based method and the polygon-based method, and focus on the fast algorithm with low memory usage, the C-LUT, and one-step polygon-based method by the 2D Fourier analysis of the 3D affine transformation. The numerical simulations and the optical experiments are presented, and several other algorithms are compared. The results show that the C-LUT algorithm and the one-step polygon-based method are efficient methods for saving calculation time. It is believed that those methods could be used in the real-time 3D holographic display in future.

  11. 3D fast reconstruction in positron emission tomography

    International Nuclear Information System (INIS)

    Egger, M.L.; Scheurer, A. Hermann; Joseph, C.; Morel, C.

    1996-01-01

    The issue of long reconstruction times in positron emission tomography (PET) has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstructions in a few minutes per frame : on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementation of computationally less intensive algorithms

  12. Fast human pose estimation using 3D Zernike descriptors

    Science.gov (United States)

    Berjón, Daniel; Morán, Francisco

    2012-03-01

    Markerless video-based human pose estimation algorithms face a high-dimensional problem that is frequently broken down into several lower-dimensional ones by estimating the pose of each limb separately. However, in order to do so they need to reliably locate the torso, for which they typically rely on time coherence and tracking algorithms. Their losing track usually results in catastrophic failure of the process, requiring human intervention and thus precluding their usage in real-time applications. We propose a very fast rough pose estimation scheme based on global shape descriptors built on 3D Zernike moments. Using an articulated model that we configure in many poses, a large database of descriptor/pose pairs can be computed off-line. Thus, the only steps that must be done on-line are the extraction of the descriptors for each input volume and a search against the database to get the most likely poses. While the result of such process is not a fine pose estimation, it can be useful to help more sophisticated algorithms to regain track or make more educated guesses when creating new particles in particle-filter-based tracking schemes. We have achieved a performance of about ten fps on a single computer using a database of about one million entries.

  13. Fast implementations of 3D PET reconstruction using vector and parallel programming techniques

    International Nuclear Information System (INIS)

    Guerrero, T.M.; Cherry, S.R.; Dahlbom, M.; Ricci, A.R.; Hoffman, E.J.

    1993-01-01

    Computationally intensive techniques that offer potential clinical use have arisen in nuclear medicine. Examples include iterative reconstruction, 3D PET data acquisition and reconstruction, and 3D image volume manipulation including image registration. One obstacle in achieving clinical acceptance of these techniques is the computational time required. This study focuses on methods to reduce the computation time for 3D PET reconstruction through the use of fast computer hardware, vector and parallel programming techniques, and algorithm optimization. The strengths and weaknesses of i860 microprocessor based workstation accelerator boards are investigated in implementations of 3D PET reconstruction

  14. A FAST METHOD FOR MEASURING THE SIMILARITY BETWEEN 3D MODEL AND 3D POINT CLOUD

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2016-06-01

    Full Text Available This paper proposes a fast method for measuring the partial Similarity between 3D Model and 3D point Cloud (SimMC. It is crucial to measure SimMC for many point cloud-related applications such as 3D object retrieval and inverse procedural modelling. In our proposed method, the surface area of model and the Distance from Model to point Cloud (DistMC are exploited as measurements to calculate SimMC. Here, DistMC is defined as the weighted distance of the distances between points sampled from model and point cloud. Similarly, Distance from point Cloud to Model (DistCM is defined as the average distance of the distances between points in point cloud and model. In order to reduce huge computational burdens brought by calculation of DistCM in some traditional methods, we define SimMC as the ratio of weighted surface area of model to DistMC. Compared to those traditional SimMC measuring methods that are only able to measure global similarity, our method is capable of measuring partial similarity by employing distance-weighted strategy. Moreover, our method is able to be faster than other partial similarity assessment methods. We demonstrate the superiority of our method both on synthetic data and laser scanning data.

  15. Anisotropic 3D texture synthesis with application to volume rendering

    DEFF Research Database (Denmark)

    Laursen, Lasse Farnung; Ersbøll, Bjarne Kjær; Bærentzen, Jakob Andreas

    2011-01-01

    images using a 12.1 megapixel camera. Next, we extend the volume rendering pipeline by creating a transfer function which yields not only color and opacity from the input intensity, but also texture coordinates for our synthesized 3D texture. Thus, we add texture to the volume rendered images....... This method is applied to a high quality visualization of a pig carcass, where samples of meat, bone, and fat have been used to produce the anisotropic 3D textures....

  16. Brain tumor locating in 3D MR volume using symmetry

    Science.gov (United States)

    Dvorak, Pavel; Bartusek, Karel

    2014-03-01

    This work deals with the automatic determination of a brain tumor location in 3D magnetic resonance volumes. The aim of this work is not the precise segmentation of the tumor and its parts but only the detection of its location. This work is the first step in the tumor segmentation process, an important topic in neuro-image processing. The algorithm expects 3D magnetic resonance volumes of brain containing a tumor. The detection is based on locating the area that breaks the left-right symmetry of the brain. This is done by multi-resolution comparing of corresponding regions in left and right hemisphere. The output of the computation is the probabilistic map of the tumor location. The created algorithm was tested on 80 volumes from publicly available BRATS databases containing 3D brain volumes afflicted by a brain tumor. These pathological structures had various sizes and shapes and were located in various parts of the brain. The locating performance of the algorithm was 85% for T1-weighted volumes, 91% for T1-weighted contrast enhanced volumes, 96% for FLAIR and T2-wieghted volumes and 95% for their combinations.

  17. Large volume syringe pump extruder for desktop 3D printers

    Directory of Open Access Journals (Sweden)

    Kira Pusch

    2018-04-01

    Full Text Available Syringe pump extruders are required for a wide range of 3D printing applications, including bioprinting, embedded printing, and food printing. However, the mass of the syringe becomes a major challenge for most printing platforms, requiring compromises in speed, resolution and/or volume. To address these issues, we have designed a syringe pump large volume extruder (LVE that is compatible with low-cost, open source 3D printers, and herein demonstrate its performance on a PrintrBot Simple Metal. Key aspects of the LVE include: (1 it is open source and compatible with open source hardware and software, making it inexpensive and widely accessible to the 3D printing community, (2 it utilizes a standard 60 mL syringe as its ink reservoir, effectively increasing print volume of the average bioprinter, (3 it is capable of retraction and high speed movements, and (4 it can print fluids using nozzle diameters as small as 100 μm, enabling the printing of complex shapes/objects when used in conjunction with the freeform reversible embedding of suspended hydrogels (FRESH 3D printing method. Printing performance of the LVE is demonstrated by utilizing alginate as a model biomaterial ink to fabricate parametric CAD models and standard calibration objects. Keywords: Additive manufacturing, 3D bioprinting, Embedded printing, FRESH, Soft materials extrusion

  18. High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation

    Directory of Open Access Journals (Sweden)

    Florian Rist

    2018-03-01

    Full Text Available Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r2 = 0.95 for berry number compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.

  19. High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation.

    Science.gov (United States)

    Rist, Florian; Herzog, Katja; Mack, Jenny; Richter, Robert; Steinhage, Volker; Töpfer, Reinhard

    2018-03-02

    Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg) was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r² = 0.95 for berry number) compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.

  20. A fast algorithm for 3D azimuthally anisotropic velocity scan

    KAUST Repository

    Hu, Jingwei

    2014-11-11

    © 2014 European Association of Geoscientists & Engineers. The conventional velocity scan can be computationally expensive for large-scale seismic data sets, particularly when the presence of anisotropy requires multiparameter scanning. We introduce a fast algorithm for 3D azimuthally anisotropic velocity scan by generalizing the previously proposed 2D butterfly algorithm for hyperbolic Radon transforms. To compute semblance in a two-parameter residual moveout domain, the numerical complexity of our algorithm is roughly O(N3logN) as opposed to O(N5) of the straightforward velocity scan, with N being the representative of the number of points in a particular dimension of either data space or parameter space. Synthetic and field data examples demonstrate the superior efficiency of the proposed algorithm.

  1. A fast algorithm for 3D azimuthally anisotropic velocity scan

    KAUST Repository

    Hu, Jingwei; Fomel, Sergey; Ying, Lexing

    2014-01-01

    © 2014 European Association of Geoscientists & Engineers. The conventional velocity scan can be computationally expensive for large-scale seismic data sets, particularly when the presence of anisotropy requires multiparameter scanning. We introduce a fast algorithm for 3D azimuthally anisotropic velocity scan by generalizing the previously proposed 2D butterfly algorithm for hyperbolic Radon transforms. To compute semblance in a two-parameter residual moveout domain, the numerical complexity of our algorithm is roughly O(N3logN) as opposed to O(N5) of the straightforward velocity scan, with N being the representative of the number of points in a particular dimension of either data space or parameter space. Synthetic and field data examples demonstrate the superior efficiency of the proposed algorithm.

  2. Force estimation from OCT volumes using 3D CNNs.

    Science.gov (United States)

    Gessert, Nils; Beringhoff, Jens; Otte, Christoph; Schlaefer, Alexander

    2018-05-04

    Estimating the interaction forces of instruments and tissue is of interest, particularly to provide haptic feedback during robot-assisted minimally invasive interventions. Different approaches based on external and integrated force sensors have been proposed. These are hampered by friction, sensor size, and sterilizability. We investigate a novel approach to estimate the force vector directly from optical coherence tomography image volumes. We introduce a novel Siamese 3D CNN architecture. The network takes an undeformed reference volume and a deformed sample volume as an input and outputs the three components of the force vector. We employ a deep residual architecture with bottlenecks for increased efficiency. We compare the Siamese approach to methods using difference volumes and two-dimensional projections. Data were generated using a robotic setup to obtain ground-truth force vectors for silicon tissue phantoms as well as porcine tissue. Our method achieves a mean average error of [Formula: see text] when estimating the force vector. Our novel Siamese 3D CNN architecture outperforms single-path methods that achieve a mean average error of [Formula: see text]. Moreover, the use of volume data leads to significantly higher performance compared to processing only surface information which achieves a mean average error of [Formula: see text]. Based on the tissue dataset, our methods shows good generalization in between different subjects. We propose a novel image-based force estimation method using optical coherence tomography. We illustrate that capturing the deformation of subsurface structures substantially improves force estimation. Our approach can provide accurate force estimates in surgical setups when using intraoperative optical coherence tomography.

  3. An efficient and accurate 3D displacements tracking strategy for digital volume correlation

    KAUST Repository

    Pan, Bing

    2014-07-01

    Owing to its inherent computational complexity, practical implementation of digital volume correlation (DVC) for internal displacement and strain mapping faces important challenges in improving its computational efficiency. In this work, an efficient and accurate 3D displacement tracking strategy is proposed for fast DVC calculation. The efficiency advantage is achieved by using three improvements. First, to eliminate the need of updating Hessian matrix in each iteration, an efficient 3D inverse compositional Gauss-Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid time-consuming integer-voxel displacement searching, a generalized reliability-guided displacement tracking strategy is designed to transfer accurate and complete initial guess of deformation for each calculation point from its computed neighbors. Third, to avoid the repeated computation of sub-voxel intensity interpolation coefficients, an interpolation coefficient lookup table is established for tricubic interpolation. The computational complexity of the proposed fast DVC and the existing typical DVC algorithms are first analyzed quantitatively according to necessary arithmetic operations. Then, numerical tests are performed to verify the performance of the fast DVC algorithm in terms of measurement accuracy and computational efficiency. The experimental results indicate that, compared with the existing DVC algorithm, the presented fast DVC algorithm produces similar precision and slightly higher accuracy at a substantially reduced computational cost. © 2014 Elsevier Ltd.

  4. An efficient and accurate 3D displacements tracking strategy for digital volume correlation

    Science.gov (United States)

    Pan, Bing; Wang, Bo; Wu, Dafang; Lubineau, Gilles

    2014-07-01

    Owing to its inherent computational complexity, practical implementation of digital volume correlation (DVC) for internal displacement and strain mapping faces important challenges in improving its computational efficiency. In this work, an efficient and accurate 3D displacement tracking strategy is proposed for fast DVC calculation. The efficiency advantage is achieved by using three improvements. First, to eliminate the need of updating Hessian matrix in each iteration, an efficient 3D inverse compositional Gauss-Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid time-consuming integer-voxel displacement searching, a generalized reliability-guided displacement tracking strategy is designed to transfer accurate and complete initial guess of deformation for each calculation point from its computed neighbors. Third, to avoid the repeated computation of sub-voxel intensity interpolation coefficients, an interpolation coefficient lookup table is established for tricubic interpolation. The computational complexity of the proposed fast DVC and the existing typical DVC algorithms are first analyzed quantitatively according to necessary arithmetic operations. Then, numerical tests are performed to verify the performance of the fast DVC algorithm in terms of measurement accuracy and computational efficiency. The experimental results indicate that, compared with the existing DVC algorithm, the presented fast DVC algorithm produces similar precision and slightly higher accuracy at a substantially reduced computational cost.

  5. 3D RISM theory with fast reciprocal-space electrostatics

    Energy Technology Data Exchange (ETDEWEB)

    Heil, Jochen; Kast, Stefan M., E-mail: stefan.kast@tu-dortmund.de [Physikalische Chemie III, Technische Universität Dortmund, Otto-Hahn-Str. 6, 44227 Dortmund (Germany)

    2015-03-21

    The calculation of electrostatic solute-solvent interactions in 3D RISM (“three-dimensional reference interaction site model”) integral equation theory is recast in a form that allows for a computational treatment analogous to the “particle-mesh Ewald” formalism as used for molecular simulations. In addition, relations that connect 3D RISM correlation functions and interaction potentials with thermodynamic quantities such as the chemical potential and average solute-solvent interaction energy are reformulated in a way that calculations of expensive real-space electrostatic terms on the 3D grid are completely avoided. These methodical enhancements allow for both, a significant speedup particularly for large solute systems and a smoother convergence of predicted thermodynamic quantities with respect to box size, as illustrated for several benchmark systems.

  6. 3D RISM theory with fast reciprocal-space electrostatics.

    Science.gov (United States)

    Heil, Jochen; Kast, Stefan M

    2015-03-21

    The calculation of electrostatic solute-solvent interactions in 3D RISM ("three-dimensional reference interaction site model") integral equation theory is recast in a form that allows for a computational treatment analogous to the "particle-mesh Ewald" formalism as used for molecular simulations. In addition, relations that connect 3D RISM correlation functions and interaction potentials with thermodynamic quantities such as the chemical potential and average solute-solvent interaction energy are reformulated in a way that calculations of expensive real-space electrostatic terms on the 3D grid are completely avoided. These methodical enhancements allow for both, a significant speedup particularly for large solute systems and a smoother convergence of predicted thermodynamic quantities with respect to box size, as illustrated for several benchmark systems.

  7. 3D RISM theory with fast reciprocal-space electrostatics

    International Nuclear Information System (INIS)

    Heil, Jochen; Kast, Stefan M.

    2015-01-01

    The calculation of electrostatic solute-solvent interactions in 3D RISM (“three-dimensional reference interaction site model”) integral equation theory is recast in a form that allows for a computational treatment analogous to the “particle-mesh Ewald” formalism as used for molecular simulations. In addition, relations that connect 3D RISM correlation functions and interaction potentials with thermodynamic quantities such as the chemical potential and average solute-solvent interaction energy are reformulated in a way that calculations of expensive real-space electrostatic terms on the 3D grid are completely avoided. These methodical enhancements allow for both, a significant speedup particularly for large solute systems and a smoother convergence of predicted thermodynamic quantities with respect to box size, as illustrated for several benchmark systems

  8. Biological modelling of fuzzy target volumes in 3D radiotherapy

    International Nuclear Information System (INIS)

    Levegruen, S.; Kampen, M. van; Waschek, T.; Engenhart, R.; Schlegel, W.

    1995-01-01

    Purpose/Objective: The outcome of each radiotherapy depends critically on the optimal choice of the target volume. The goal of the radiotherapist is to include all tumor spread at the same time as saving as much healthy tissue as possible. Even when the information of all imaging modalities is combined, the diagnostic techniques are not sensitive and specific enough to visualize all microscopic tumor cell spread. Due to this lack of information there is room for different interpretations concerning the extend of the target volume, leading to a fuzzy target volume. The aim of this work is to develop a model to score different target volume boundaries within the region of diagnostic uncertainty in terms of tumor control probability (TCP) and normal tissue complication probabilities (NTCP). Materials and Methods: In order to assess the region of diagnostic uncertainty, the radiotherapist defines interactively a minimal planning target volume that absolutely must be irradiated according to the diagnostic information available and a maximal planning target volume outside which no tumor cell spread is expected. For the NTCP calculation we use the Lyman 4 parameter model to estimate the response of an organ at risk to a uniform partial volume irradiation. The TCP calculation is based on the Poisson model of cell killing. The TCP estimation depends not only on volume, dose, clonogenic cell density and the α parameter of the linear quadratic model but also on the probability to find clonogenic cells in the considered volume. Inside the minimal PTV this probability is 1, outside the maximal PTV it is 0. Therefore all voxels inside the minimal PTV are assigned the value of 1 with respect to the target volume, all voxels outside the maximal PTV the value of 0. For voxels in the region of uncertainty in between, a 3D linear interpolation is performed. Here we assume the probability to follow the interpolated values. Starting with the minimal PTV, the expected gain in TCP and

  9. Registration of 3D spectral OCT volumes using 3D SIFT feature point matching

    Science.gov (United States)

    Niemeijer, Meindert; Garvin, Mona K.; Lee, Kyungmoo; van Ginneken, Bram; Abràmoff, Michael D.; Sonka, Milan

    2009-02-01

    The recent introduction of next generation spectral OCT scanners has enabled routine acquisition of high resolution, 3D cross-sectional volumetric images of the retina. 3D OCT is used in the detection and management of serious eye diseases such as glaucoma and age-related macular degeneration. For follow-up studies, image registration is a vital tool to enable more precise, quantitative comparison of disease states. This work presents a registration method based on a recently introduced extension of the 2D Scale-Invariant Feature Transform (SIFT) framework1 to 3D.2 The SIFT feature extractor locates minima and maxima in the difference of Gaussian scale space to find salient feature points. It then uses histograms of the local gradient directions around each found extremum in 3D to characterize them in a 4096 element feature vector. Matching points are found by comparing the distance between feature vectors. We apply this method to the rigid registration of optic nerve head- (ONH) and macula-centered 3D OCT scans of the same patient that have only limited overlap. Three OCT data set pairs with known deformation were used for quantitative assessment of the method's robustness and accuracy when deformations of rotation and scaling were considered. Three-dimensional registration accuracy of 2.0+/-3.3 voxels was observed. The accuracy was assessed as average voxel distance error in N=1572 matched locations. The registration method was applied to 12 3D OCT scans (200 x 200 x 1024 voxels) of 6 normal eyes imaged in vivo to demonstrate the clinical utility and robustness of the method in a real-world environment.

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

    Directory of Open Access Journals (Sweden)

    Xing Zhao

    2009-01-01

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

  11. GOTHIC 3D applicability to fast hydrogen combustions

    International Nuclear Information System (INIS)

    Lee, Jung Jae; Park, Goon Cherl; Lee, Byung Chul; Yoo, Ho Jong; Kim, Hyeong Taek; Oh, Seung Jong

    2004-01-01

    Under severe accidents in nuclear power plant (NPP), the hydrogen can be generated by chemical reactions and may threaten the containment integrity via hydrogen combustion. For containment analyses, three-dimensional mechanistic code, GOTHIC had to be applied near source compartments in order to predict whether highly reactive gas mixture can be formed or not under hydrogen mitigation system (HMS) working. For its applicability, this paper presents numerical calculation results of GOTHIC 3D on some hydrogen combustion experiments, which are the FLAME (Sandia National Lab.) experiments, the LSVCTF (AECL Whiteshell Lab.) experiments and the SNU-2D (Seoul National Univ.) experiments. A technical basis for the modeling of the large- and small-scale facilities was developed through sensitivity studies on cell size and combustion modeling parameters. It was found that for large-scale facilities, there were no significant differences in the results with different turbulent burn options, while for small-scale facility, the option using the eddy dissipation concept showed the faster flame propagations. The flame velocity became larger with smaller burn parameters such as the flame thickness δ f and the burn temperature limit T lim . The best estimate modeling parameters found from this study would be applied to real plant simulation of GOTHIC 3D later

  12. An Algorithm for Fast Computation of 3D Zernike Moments for Volumetric Images

    OpenAIRE

    Hosny, Khalid M.; Hafez, Mohamed A.

    2012-01-01

    An algorithm was proposed for very fast and low-complexity computation of three-dimensional Zernike moments. The 3D Zernike moments were expressed in terms of exact 3D geometric moments where the later are computed exactly through the mathematical integration of the monomial terms over the digital image/object voxels. A new symmetry-based method was proposed to compute 3D Zernike moments with 87% reduction in the computational complexity. A fast 1D cascade algorithm was also employed to add m...

  13. 3D FaceCam: a fast and accurate 3D facial imaging device for biometrics applications

    Science.gov (United States)

    Geng, Jason; Zhuang, Ping; May, Patrick; Yi, Steven; Tunnell, David

    2004-08-01

    Human faces are fundamentally three-dimensional (3D) objects, and each face has its unique 3D geometric profile. The 3D geometric features of a human face can be used, together with its 2D texture, for rapid and accurate face recognition purposes. Due to the lack of low-cost and robust 3D sensors and effective 3D facial recognition (FR) algorithms, almost all existing FR systems use 2D face images. Genex has developed 3D solutions that overcome the inherent problems in 2D while also addressing limitations in other 3D alternatives. One important aspect of our solution is a unique 3D camera (the 3D FaceCam) that combines multiple imaging sensors within a single compact device to provide instantaneous, ear-to-ear coverage of a human face. This 3D camera uses three high-resolution CCD sensors and a color encoded pattern projection system. The RGB color information from each pixel is used to compute the range data and generate an accurate 3D surface map. The imaging system uses no moving parts and combines multiple 3D views to provide detailed and complete 3D coverage of the entire face. Images are captured within a fraction of a second and full-frame 3D data is produced within a few seconds. This described method provides much better data coverage and accuracy in feature areas with sharp features or details (such as the nose and eyes). Using this 3D data, we have been able to demonstrate that a 3D approach can significantly improve the performance of facial recognition. We have conducted tests in which we have varied the lighting conditions and angle of image acquisition in the "field." These tests have shown that the matching results are significantly improved when enrolling a 3D image rather than a single 2D image. With its 3D solutions, Genex is working toward unlocking the promise of powerful 3D FR and transferring FR from a lab technology into a real-world biometric solution.

  14. Rigid 3D-3D registration of TOF MRA integrating vessel segmentation for quantification of recurrence volumes after coiling cerebral aneurysm

    International Nuclear Information System (INIS)

    Saering, Dennis; Forkert, Nils Daniel; Fiehler, Jens; Ries, Thorsten

    2012-01-01

    A fast and reproducible quantification of the recurrence volume of coiled aneurysms is required to enable a more timely evaluation of new coils. This paper presents two registration schemes for the semi-automatic quantification of aneurysm recurrence volumes based on baseline and follow-up 3D MRA TOF datasets. The quantification of shape changes requires a previous definition of corresponding structures in both datasets. For this, two different rigid registration methods have been developed and evaluated. Besides a state-of-the-art rigid registration method, a second approach integrating vessel segmentations is presented. After registration, the aneurysm recurrence volume can be calculated based on the difference image. The computed volumes were compared to manually extracted volumes. An evaluation based on 20 TOF MRA datasets (baseline and follow-up) of ten patients showed that both registration schemes are generally capable of providing sufficient registration results. Regarding the quantification of aneurysm recurrence volumes, the results suggest that the second segmentation-based registration method yields better results, while a reduction of the computation and interaction time is achieved at the same time. The proposed registration scheme incorporating vessel segmentation enables an improved quantification of recurrence volumes of coiled aneurysms with reduced computation and interaction time. (orig.)

  15. PF2fit: Polar Fast Fourier Matched Alignment of Atomistic Structures with 3D Electron Microscopy Maps.

    Directory of Open Access Journals (Sweden)

    Radhakrishna Bettadapura

    2015-10-01

    Full Text Available There continue to be increasing occurrences of both atomistic structure models in the PDB (possibly reconstructed from X-ray diffraction or NMR data, and 3D reconstructed cryo-electron microscopy (3D EM maps (albeit at coarser resolution of the same or homologous molecule or molecular assembly, deposited in the EMDB. To obtain the best possible structural model of the molecule at the best achievable resolution, and without any missing gaps, one typically aligns (match and fits the atomistic structure model with the 3D EM map. We discuss a new algorithm and generalized framework, named PF(2 fit (Polar Fast Fourier Fitting for the best possible structural alignment of atomistic structures with 3D EM. While PF(2 fit enables only a rigid, six dimensional (6D alignment method, it augments prior work on 6D X-ray structure and 3D EM alignment in multiple ways: Scoring. PF(2 fit includes a new scoring scheme that, in addition to rewarding overlaps between the volumes occupied by the atomistic structure and 3D EM map, rewards overlaps between the volumes complementary to them. We quantitatively demonstrate how this new complementary scoring scheme improves upon existing approaches. PF(2 fit also includes two scoring functions, the non-uniform exterior penalty and the skeleton-secondary structure score, and implements the scattering potential score as an alternative to traditional Gaussian blurring. Search. PF(2 fit utilizes a fast polar Fourier search scheme, whose main advantage is the ability to search over uniformly and adaptively sampled subsets of the space of rigid-body motions. PF(2 fit also implements a new reranking search and scoring methodology that considerably improves alignment metrics in results obtained from the initial search.

  16. A three-dimensional gradient refocused 3D volume imaging of discoid lateral meniscus

    International Nuclear Information System (INIS)

    Araki, Yutaka; Ootani, Masatoshi; Furukawa, Tomoaki; Yamamoto, Tadatsuka; Tomoda, Kaname; Tsukaguchi, Isao; Mitomo, Masanori.

    1991-01-01

    An axial 3D volume scan with MRI was applied to the evaluation of discoid lateral meniscus of the knee. By 0.7 mm-thick thin sliced and gapless images with volume scan, characteristically elongated appearance of discoid lateral meniscus was clearly depicted. These MR findings completely accorded with those on arthroscopy. Our conclusion is that an axial 3D volume scan was essential to the diagnosis of discoid lateral meniscus. (author)

  17. An Algorithm for Fast Computation of 3D Zernike Moments for Volumetric Images

    Directory of Open Access Journals (Sweden)

    Khalid M. Hosny

    2012-01-01

    Full Text Available An algorithm was proposed for very fast and low-complexity computation of three-dimensional Zernike moments. The 3D Zernike moments were expressed in terms of exact 3D geometric moments where the later are computed exactly through the mathematical integration of the monomial terms over the digital image/object voxels. A new symmetry-based method was proposed to compute 3D Zernike moments with 87% reduction in the computational complexity. A fast 1D cascade algorithm was also employed to add more complexity reduction. The comparison with existing methods was performed, where the numerical experiments and the complexity analysis ensured the efficiency of the proposed method especially with image and objects of large sizes.

  18. Three Dimensional Fast Exact Euclidean Distance (3D-FEED) Maps

    NARCIS (Netherlands)

    Latecki, L.J.; Schouten, Theo E.; Mount, D.M.; Kuppens, Harco C.; Wu, A.Y.; van den Broek, Egon

    2006-01-01

    In image and video analysis, distance maps are frequently used. They provide the (Euclidean) distance (ED) of background pixels to the nearest object pixel. Recently, the Fast Exact Euclidean Distance (FEED) transformation was launched. In this paper, we present the three dimensional (3D) version of

  19. A fast nonlinear conjugate gradient based method for 3D frictional contact problems

    NARCIS (Netherlands)

    Zhao, J.; Vollebregt, E.A.H.; Oosterlee, C.W.

    2014-01-01

    This paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from a 3D frictional contact problem. It incorporates an active set strategy with a nonlinear conjugate gradient method. One novelty is to consider the tractions of each slip element in a polar

  20. A fast nonlinear conjugate gradient based method for 3D concentrated frictional contact problems

    NARCIS (Netherlands)

    J. Zhao (Jing); E.A.H. Vollebregt (Edwin); C.W. Oosterlee (Cornelis)

    2015-01-01

    htmlabstractThis paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from 3D concentrated frictional shift and rolling contact problems with dry Coulomb friction. The solver combines an active set strategy with a nonlinear conjugate gradient method. One

  1. Femtosecond laser pulses for fast 3-D surface profilometry of microelectronic step-structures.

    Science.gov (United States)

    Joo, Woo-Deok; Kim, Seungman; Park, Jiyong; Lee, Keunwoo; Lee, Joohyung; Kim, Seungchul; Kim, Young-Jin; Kim, Seung-Woo

    2013-07-01

    Fast, precise 3-D measurement of discontinuous step-structures fabricated on microelectronic products is essential for quality assurance of semiconductor chips, flat panel displays, and photovoltaic cells. Optical surface profilers of low-coherence interferometry have long been used for the purpose, but the vertical scanning range and speed are limited by the micro-actuators available today. Besides, the lateral field-of-view extendable for a single measurement is restricted by the low spatial coherence of broadband light sources. Here, we cope with the limitations of the conventional low-coherence interferometer by exploiting unique characteristics of femtosecond laser pulses, i.e., low temporal but high spatial coherence. By scanning the pulse repetition rate with direct reference to the Rb atomic clock, step heights of ~69.6 μm are determined with a repeatability of 10.3 nm. The spatial coherence of femtosecond pulses provides a large field-of-view with superior visibility, allowing for a high volume measurement rate of ~24,000 mm3/s.

  2. Volume-Rendered 3D Display Of MR Angiograms in the Diagnosis of Cerebral Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K.; Katase, S.; Hachiya, J. [Kyorin Univ. School of Medicine, Tokyo (Japan). Dept. of Radiology; Shiokawa, Y. [Kyorin Univ. School of Medicine, Tokyo (Japan). Dept. of Neurosurgery

    2003-11-01

    Purpose: To determine whether application of a volume-rendered display of 3D time-of-flight (TOF) MR angiography could assist the diagnosis of cerebral arteriovenous malformations (AVMs). Material and Methods: Volume-rendered 3D images of postcontrast 3D time-of-flight MR angiography were compared with conventional angiograms in 12 patients. The correlation between the 3D images and the operative findings was also analyzed in 5 patients. Results: The 3D-displayed images showed all of the feeders and drainers in 10 and 9 patients, respectively. In all patients, the nidus was three-dimensionally visualized. In 3 patients with hematomas, the relationship between the hematoma and the AVM was well demonstrated. The 3D images corresponded well with the operative findings in the 5 patients. Conclusion: This method is of help in assessing the relationship between the components of an AVM as well as that between an AVM and an associated hematoma.

  3. Volume-Rendered 3D Display Of MR Angiograms in the Diagnosis of Cerebral Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Tsuchiya, K.; Katase, S.; Hachiya, J.; Shiokawa, Y.

    2003-01-01

    Purpose: To determine whether application of a volume-rendered display of 3D time-of-flight (TOF) MR angiography could assist the diagnosis of cerebral arteriovenous malformations (AVMs). Material and Methods: Volume-rendered 3D images of postcontrast 3D time-of-flight MR angiography were compared with conventional angiograms in 12 patients. The correlation between the 3D images and the operative findings was also analyzed in 5 patients. Results: The 3D-displayed images showed all of the feeders and drainers in 10 and 9 patients, respectively. In all patients, the nidus was three-dimensionally visualized. In 3 patients with hematomas, the relationship between the hematoma and the AVM was well demonstrated. The 3D images corresponded well with the operative findings in the 5 patients. Conclusion: This method is of help in assessing the relationship between the components of an AVM as well as that between an AVM and an associated hematoma

  4. Sonographic measurement of thyroid gland volume: A comparison of 2D and 3D ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Ying, Michael [Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)]. E-mail: ormying@polyu.edu.hk; Sin Manhong [Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Pang, Shuk-fan [Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2005-11-01

    Aims: This study was undertaken to investigate the inter-observer reproducibility of 2D and 3D ultrasound in the measurement of thyroid gland volume. The symmetry of thyroid lobes in healthy subjects was also investigated. Materials and methods: The volume of the left and right lobes of the thyroid gland was measured in 20 healthy subjects (10 men and 10 women) using 2D and 3D ultrasound. On 2D ultrasound, the thyroid lobe volume was calculated by ellipsoid equation (volume = {pi}/6 x craniocaudal x mediolateral x anteroposterior dimensions), whereas 3D ultrasound volumetric measurements were performed with a 3D add-on system. In each subject, the thyroid gland was scanned by two operators to investigate inter-observer variability. Results: There was a moderate agreement between 2D and 3D ultrasound in the measurement of thyroid volume (r = 0.77). 3D ultrasound (90%) had a higher inter-observer reproducibility than 2D ultrasound (85%) in the measurements. About 74% of healthy subjects had the right thyroid lobe larger than the left lobe. Conclusion: 3D ultrasound is useful in the measurement of thyroid volume with a higher reproducibility than 2D ultrasound. Asymmetry of thyroid lobes was noted in healthy subjects.

  5. Sonographic measurement of thyroid gland volume: A comparison of 2D and 3D ultrasound

    International Nuclear Information System (INIS)

    Ying, Michael; Sin Manhong; Pang, Shuk-fan

    2005-01-01

    Aims: This study was undertaken to investigate the inter-observer reproducibility of 2D and 3D ultrasound in the measurement of thyroid gland volume. The symmetry of thyroid lobes in healthy subjects was also investigated. Materials and methods: The volume of the left and right lobes of the thyroid gland was measured in 20 healthy subjects (10 men and 10 women) using 2D and 3D ultrasound. On 2D ultrasound, the thyroid lobe volume was calculated by ellipsoid equation (volume = π/6 x craniocaudal x mediolateral x anteroposterior dimensions), whereas 3D ultrasound volumetric measurements were performed with a 3D add-on system. In each subject, the thyroid gland was scanned by two operators to investigate inter-observer variability. Results: There was a moderate agreement between 2D and 3D ultrasound in the measurement of thyroid volume (r = 0.77). 3D ultrasound (90%) had a higher inter-observer reproducibility than 2D ultrasound (85%) in the measurements. About 74% of healthy subjects had the right thyroid lobe larger than the left lobe. Conclusion: 3D ultrasound is useful in the measurement of thyroid volume with a higher reproducibility than 2D ultrasound. Asymmetry of thyroid lobes was noted in healthy subjects

  6. Intracranial MRA: single volume vs. multiple thin slab 3D time-of-flight acquisition.

    Science.gov (United States)

    Davis, W L; Warnock, S H; Harnsberger, H R; Parker, D L; Chen, C X

    1993-01-01

    Single volume three-dimensional (3D) time-of-flight (TOF) MR angiography is the most commonly used noninvasive method for evaluating the intracranial vasculature. The sensitivity of this technique to signal loss from flow saturation limits its utility. A recently developed multislab 3D TOF technique, MOTSA, is less affected by flow saturation and would therefore be expected to yield improved vessel visualization. To study this hypothesis, intracranial MR angiograms were obtained on 10 volunteers using three techniques: MOTSA, single volume 3D TOF using a standard 4.9 ms TE (3D TOFA), and single volume 3D TOF using a 6.8 ms TE (3D TOFB). All three sets of axial source images and maximum intensity projection (MIP) images were reviewed. Each exam was evaluated for the number of intracranial vessels visualized. A total of 502 vessel segments were studied with each technique. With use of the MIP images, 86% of selected vessels were visualized with MOTSA, 64% with 3D TOFA (TE = 4.9 ms), and 67% with TOFB (TE = 6.8 ms). Similarly, with the axial source images, 91% of selected vessels were visualized with MOTSA, 77% with 3D TOFA (TE = 4.9 ms), and 82% with 3D TOFB (TE = 6.8 ms). There is improved visualization of selected intracranial vessels in normal volunteers with MOTSA as compared with single volume 3D TOF. These improvements are believed to be primarily a result of decreased sensitivity to flow saturation seen with the MOTSA technique. No difference in overall vessel visualization was noted for the two single volume 3D TOF techniques.

  7. 3D Fast Spin Echo T2-weighted Contrast for Imaging the Female Cervix

    Science.gov (United States)

    Vargas Sanchez, Andrea Fernanda

    Magnetic Resonance Imaging (MRI) with T2-weighted contrast is the preferred modality for treatment planning and monitoring of cervical cancer. Current clinical protocols image the volume of interest multiple times with two dimensional (2D) T2-weighted MRI techniques. It is of interest to replace these multiple 2D acquisitions with a single three dimensional (3D) MRI acquisition to save time. However, at present the image contrast of standard 3D MRI does not distinguish cervical healthy tissue from cancerous tissue. The purpose of this thesis is to better understand the underlying factors that govern the contrast of 3D MRI and exploit this understanding via sequence modifications to improve the contrast. Numerical simulations are developed to predict observed contrast alterations and to propose an improvement. Improvements of image contrast are shown in simulation and with healthy volunteers. Reported results are only preliminary but a promising start to establish definitively 3D MRI for cervical cancer applications.

  8. Spatial resolution properties in 3D fast spin-echo using variable refocusing flip angles

    International Nuclear Information System (INIS)

    Ozaki, Masanori; Mizukami, Shinya; Hata, Hirofumi; Sato, Mayumi; Komi, Syotaro; Miyati, Tosiaki; Nozaki, Atsushi

    2011-01-01

    A new 3-dimensional fast spin-echo (3D FSE) method that uses a variable refocusing flip angle technique has recently been applied to imaging. The imaging pulse sequence can inhibit T 2 decay by varying the refocusing flip angle. Use of a long echo train length allows acquisition of 3D T 2 -weighted images with less blurring in a short scan time. The smaller refocusing flip angle in the new 3D FSE method than in the conventional method can reduce the specific absorption rate. However, T 2 decay differs between the new and conventional 3D FSE methods, so the resolution properties of the 2 methods may differ. We investigated the resolution properties of the new 3D FSE method using a variable refocusing flip angle technique. Varying the refocusing flip angle resulted in different resolution properties for the new 3D FSE method compared to the conventional method, a difference particularly noticeable when the imaging parameters were set for obtaining proton density weighted images. (author)

  9. Accuracy of volume measurement using 3D ultrasound and development of CT-3D US image fusion algorithm for prostate cancer radiotherapy

    International Nuclear Information System (INIS)

    Baek, Jihye; Huh, Jangyoung; Hyun An, So; Oh, Yoonjin; Kim, Myungsoo; Kim, DongYoung; Chung, Kwangzoo; Cho, Sungho; Lee, Rena

    2013-01-01

    Purpose: To evaluate the accuracy of measuring volumes using three-dimensional ultrasound (3D US), and to verify the feasibility of the replacement of CT-MR fusion images with CT-3D US in radiotherapy treatment planning. Methods: Phantoms, consisting of water, contrast agent, and agarose, were manufactured. The volume was measured using 3D US, CT, and MR devices. A CT-3D US and MR-3D US image fusion software was developed using the Insight Toolkit library in order to acquire three-dimensional fusion images. The quality of the image fusion was evaluated using metric value and fusion images. Results: Volume measurement, using 3D US, shows a 2.8 ± 1.5% error, 4.4 ± 3.0% error for CT, and 3.1 ± 2.0% error for MR. The results imply that volume measurement using the 3D US devices has a similar accuracy level to that of CT and MR. Three-dimensional image fusion of CT-3D US and MR-3D US was successfully performed using phantom images. Moreover, MR-3D US image fusion was performed using human bladder images. Conclusions: 3D US could be used in the volume measurement of human bladders and prostates. CT-3D US image fusion could be used in monitoring the target position in each fraction of external beam radiation therapy. Moreover, the feasibility of replacing the CT-MR image fusion to the CT-3D US in radiotherapy treatment planning was verified.

  10. Phantom investigation of 3D motion-dependent volume aliasing during CT simulation for radiation therapy planning

    International Nuclear Information System (INIS)

    Tanyi, James A; Fuss, Martin; Varchena, Vladimir; Lancaster, Jack L; Salter, Bill J

    2007-01-01

    To quantify volumetric and positional aliasing during non-gated fast- and slow-scan acquisition CT in the presence of 3D target motion. Single-slice fast, single-slice slow, and multi-slice fast scan helical CTs were acquired of dynamic spherical targets (1 and 3.15 cm in diameter), embedded in an anthropomorphic phantom. 3D target motions typical of clinically observed tumor motion parameters were investigated. Motion excursions included ± 5, ± 10, and ± 15 mm displacements in the S-I direction synchronized with constant displacements of ± 5 and ± 2 mm in the A-P and lateral directions, respectively. For each target, scan technique, and motion excursion, eight different initial motion-to-scan phase relationships were investigated. An anticipated general trend of target volume overestimation was observed. The mean percentage overestimation of the true physical target volume typically increased with target motion amplitude and decreasing target diameter. Slow-scan percentage overestimations were larger, and better approximated the time-averaged motion envelope, as opposed to fast-scans. Motion induced centroid misrepresentation was greater in the S-I direction for fast-scan techniques, and transaxial direction for the slow-scan technique. Overestimation is fairly uniform for slice widths < 5 mm, beyond which there is gross overestimation. Non-gated CT imaging of targets describing clinically relevant, 3D motion results in aliased overestimation of the target volume and misrepresentation of centroid location, with little or no correlation between the physical target geometry and the CT-generated target geometry. Slow-scan techniques are a practical method for characterizing time-averaged target position. Fast-scan techniques provide a more reliable, albeit still distorted, target margin

  11. New version of the reactor dynamics code DYN3D for Sodium cooled Fast Reactor analyses

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Evgeny [Ecole Polytechnique Federale de Lausanne (Switzerland); Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany); Fridman, Emil; Bilodid, Yuri; Kliem, Soeren [Helmholtz-Zentrum Dresden-Rossendorf (HZDR) e.V., Dresden (Germany)

    2017-07-15

    The reactor dynamics code DYN3D being developed at the Helmholtz-Zentrum Dresden-Rossendorf is currently under extension for Sodium cooled Fast Reactor analyses. This paper provides an overview on the new version of DYN3D to be used for SFR core calculations. The current article shortly describes the newly implemented thermal mechanical models, which can account for thermal expansion effects of the reactor core. Furthermore, the methodology used in Sodium cooled Fast Reactor analyses to generate homogenized few-group cross sections is summarized. The conducted and planned verification and validation studies are briefly presented. Related publications containing more detailed descriptions are outlined for the completeness of this overview.

  12. Fast implementations of reconstruction-based scatter compensation in fully 3D SPECT image reconstruction

    International Nuclear Information System (INIS)

    Kadrmas, Dan J.; Karimi, Seemeen S.; Frey, Eric C.; Tsui, Benjamin M.W.

    1998-01-01

    Accurate scatter compensation in SPECT can be performed by modelling the scatter response function during the reconstruction process. This method is called reconstruction-based scatter compensation (RBSC). It has been shown that RBSC has a number of advantages over other methods of compensating for scatter, but using RBSC for fully 3D compensation has resulted in prohibitively long reconstruction times. In this work we propose two new methods that can be used in conjunction with existing methods to achieve marked reductions in RBSC reconstruction times. The first method, coarse-grid scatter modelling, significantly accelerates the scatter model by exploiting the fact that scatter is dominated by low-frequency information. The second method, intermittent RBSC, further accelerates the reconstruction process by limiting the number of iterations during which scatter is modelled. The fast implementations were evaluated using a Monte Carlo simulated experiment of the 3D MCAT phantom with 99m Tc tracer, and also using experimentally acquired data with 201 Tl tracer. Results indicated that these fast methods can reconstruct, with fully 3D compensation, images very similar to those obtained using standard RBSC methods, and in reconstruction times that are an order of magnitude shorter. Using these methods, fully 3D iterative reconstruction with RBSC can be performed well within the realm of clinically realistic times (under 10 minutes for 64x64x24 image reconstruction). (author)

  13. On the major DYN3D developments for fast reactor design and transient analysis

    International Nuclear Information System (INIS)

    Merk, B.; Kliem, S.

    2013-01-01

    Due to the French project ASTRID, the European CP-ESFR project, and the MYRRHA/FASTEF project, the research work on fast reactors has got a new push in Europe. Additionally to this European projects a strong project is growing in Russia based on the lead cooled fast reactor design BREST. Following this trend, the Institute of Resource Ecology at the Helmholtz-Zentrum Dresden-Rossendorf has decided to start several projects dedicated to fast reactor technology, among them the extension of the well validated LWR core simulator DYN3D. The new developments, first validation results, and the next strategic steps for the adaption of the code for the improved simulation of fast reactor cores are presented. (orig.)

  14. On the major DYN3D developments for fast reactor design and transient analysis

    Energy Technology Data Exchange (ETDEWEB)

    Merk, B.; Kliem, S. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Reactor Safety Div.

    2013-07-01

    Due to the French project ASTRID, the European CP-ESFR project, and the MYRRHA/FASTEF project, the research work on fast reactors has got a new push in Europe. Additionally to this European projects a strong project is growing in Russia based on the lead cooled fast reactor design BREST. Following this trend, the Institute of Resource Ecology at the Helmholtz-Zentrum Dresden-Rossendorf has decided to start several projects dedicated to fast reactor technology, among them the extension of the well validated LWR core simulator DYN3D. The new developments, first validation results, and the next strategic steps for the adaption of the code for the improved simulation of fast reactor cores are presented. (orig.)

  15. Fast, accurate, small-scale 3D scene capture using a low-cost depth sensor

    Science.gov (United States)

    Carey, Nicole; Nagpal, Radhika; Werfel, Justin

    2017-01-01

    Commercially available depth sensing devices are primarily designed for domains that are either macroscopic, or static. We develop a solution for fast microscale 3D reconstruction, using off-the-shelf components. By the addition of lenses, precise calibration of camera internals and positioning, and development of bespoke software, we turn an infrared depth sensor designed for human-scale motion and object detection into a device with mm-level accuracy capable of recording at up to 30Hz. PMID:28758159

  16. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods.

    Science.gov (United States)

    van der Kleij, Lisa A; de Bresser, Jeroen; Hendrikse, Jeroen; Siero, Jeroen C W; Petersen, Esben T; De Vis, Jill B

    2018-01-01

    In previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim of this study was to assess the precision of the BPV and ICV measurements of the CSF MRI sequence and to validate the CSF MRI sequence by comparison with 3D T1-based brain segmentation methods. Ten healthy volunteers (2 females; median age 28 years) were scanned (3T MRI) twice with repositioning in between. The scan protocol consisted of a low resolution (LR) CSF sequence (0:57min), a high resolution (HR) CSF sequence (3:21min) and a 3D T1-weighted sequence (6:47min). Data of the HR 3D-T1-weighted images were downsampled to obtain LR T1-weighted images (reconstructed imaging time: 1:59 min). Data of the CSF MRI sequences was automatically segmented using in-house software. The 3D T1-weighted images were segmented using FSL (5.0), SPM12 and FreeSurfer (5.3.0). The mean absolute differences for BPV and ICV between the first and second scan for CSF LR (BPV/ICV: 12±9/7±4cc) and CSF HR (5±5/4±2cc) were comparable to FSL HR (9±11/19±23cc), FSL LR (7±4, 6±5cc), FreeSurfer HR (5±3/14±8cc), FreeSurfer LR (9±8, 12±10cc), and SPM HR (5±3/4±7cc), and SPM LR (5±4, 5±3cc). The correlation between the measured volumes of the CSF sequences and that measured by FSL, FreeSurfer and SPM HR and LR was very good (all Pearson's correlation coefficients >0.83, R2 .67-.97). The results from the downsampled data and the high-resolution data were similar. Both CSF MRI sequences have a precision comparable to, and a very good correlation with established 3D T1-based automated segmentations methods for the segmentation of BPV and ICV. However, the short imaging time of the fast CSF MRI sequence is superior to the 3D T1 sequence on which segmentation with established methods is performed.

  17. Combining 3d Volume and Mesh Models for Representing Complicated Heritage Buildings

    Science.gov (United States)

    Tsai, F.; Chang, H.; Lin, Y.-W.

    2017-08-01

    This study developed a simple but effective strategy to combine 3D volume and mesh models for representing complicated heritage buildings and structures. The idea is to seamlessly integrate 3D parametric or polyhedral models and mesh-based digital surfaces to generate a hybrid 3D model that can take advantages of both modeling methods. The proposed hybrid model generation framework is separated into three phases. Firstly, after acquiring or generating 3D point clouds of the target, these 3D points are partitioned into different groups. Secondly, a parametric or polyhedral model of each group is generated based on plane and surface fitting algorithms to represent the basic structure of that region. A "bare-bones" model of the target can subsequently be constructed by connecting all 3D volume element models. In the third phase, the constructed bare-bones model is used as a mask to remove points enclosed by the bare-bones model from the original point clouds. The remaining points are then connected to form 3D surface mesh patches. The boundary points of each surface patch are identified and these boundary points are projected onto the surfaces of the bare-bones model. Finally, new meshes are created to connect the projected points and original mesh boundaries to integrate the mesh surfaces with the 3D volume model. The proposed method was applied to an open-source point cloud data set and point clouds of a local historical structure. Preliminary results indicated that the reconstructed hybrid models using the proposed method can retain both fundamental 3D volume characteristics and accurate geometric appearance with fine details. The reconstructed hybrid models can also be used to represent targets in different levels of detail according to user and system requirements in different applications.

  18. Volume Attenuation and High Frequency Loss as Auditory Depth Cues in Stereoscopic 3D Cinema

    Science.gov (United States)

    Manolas, Christos; Pauletto, Sandra

    2014-09-01

    Assisted by the technological advances of the past decades, stereoscopic 3D (S3D) cinema is currently in the process of being established as a mainstream form of entertainment. The main focus of this collaborative effort is placed on the creation of immersive S3D visuals. However, with few exceptions, little attention has been given so far to the potential effect of the soundtrack on such environments. The potential of sound both as a means to enhance the impact of the S3D visual information and to expand the S3D cinematic world beyond the boundaries of the visuals is large. This article reports on our research into the possibilities of using auditory depth cues within the soundtrack as a means of affecting the perception of depth within cinematic S3D scenes. We study two main distance-related auditory cues: high-end frequency loss and overall volume attenuation. A series of experiments explored the effectiveness of these auditory cues. Results, although not conclusive, indicate that the studied auditory cues can influence the audience judgement of depth in cinematic 3D scenes, sometimes in unexpected ways. We conclude that 3D filmmaking can benefit from further studies on the effectiveness of specific sound design techniques to enhance S3D cinema.

  19. Gaze3DFix: Detecting 3D fixations with an ellipsoidal bounding volume.

    Science.gov (United States)

    Weber, Sascha; Schubert, Rebekka S; Vogt, Stefan; Velichkovsky, Boris M; Pannasch, Sebastian

    2017-10-26

    Nowadays, the use of eyetracking to determine 2-D gaze positions is common practice, and several approaches to the detection of 2-D fixations exist, but ready-to-use algorithms to determine eye movements in three dimensions are still missing. Here we present a dispersion-based algorithm with an ellipsoidal bounding volume that estimates 3D fixations. Therefore, 3D gaze points are obtained using a vector-based approach and are further processed with our algorithm. To evaluate the accuracy of our method, we performed experimental studies with real and virtual stimuli. We obtained good congruence between stimulus position and both the 3D gaze points and the 3D fixation locations within the tested range of 200-600 mm. The mean deviation of the 3D fixations from the stimulus positions was 17 mm for the real as well as for the virtual stimuli, with larger variances at increasing stimulus distances. The described algorithms are implemented in two dynamic linked libraries (Gaze3D.dll and Fixation3D.dll), and we provide a graphical user interface (Gaze3DFixGUI.exe) that is designed for importing 2-D binocular eyetracking data and calculating both 3D gaze points and 3D fixations using the libraries. The Gaze3DFix toolkit, including both libraries and the graphical user interface, is available as open-source software at https://github.com/applied-cognition-research/Gaze3DFix .

  20. MR Imaging of the Internal Auditory Canal and Inner Ear at 3T: Comparison between 3D Driven Equilibrium and 3D Balanced Fast Field Echo Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Jun Soo; Kim, Hyung Jin; Yim, Yoo Jeong; Kim, Sung Tae; Jeon, Pyoung; Kim, Keon Ha [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Sam Soo; Jeon, Yong Hwan; Lee, Ji Won [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of)

    2008-06-15

    To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). Thirty ears of 15 subjects (7 men and 8 women; age range, 22 71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear

  1. Left ventricular ejection fraction and volumes as measured by 3D echocardiography and ultrafast computed tomography

    International Nuclear Information System (INIS)

    Vieira, Marcelo Luiz Campos; Nomura, Cesar H.; Tranchesi Junior, Bernardino; Oliveira, Wercules A. de; Naccarato, Gustavo; Serpa, Bruna S.; Passos, Rodrigo B.D.; Funari, Marcelo B. G.; Fischer, Claudio H.; Morhy, Samira S.

    2009-01-01

    Background: Real-time three-dimensional echocardiography (RT-3D-Echo) and ultrafast computed tomography (CT) are two novel methods for the analysis of LV ejection fraction and volumes. Objective: To compare LVEF and volume measurements as obtained using RT-3D-Echo and ultrafast CT. Methods: Thirty nine consecutive patients (27 men, mean age of 57+- 12 years) were studied using RT-3D-Echo and 64-slice ultrafast CT. LVEF and LV volumes were analyzed. Statistical analysis: coefficient of correlation (r: Pearson), Bland-Altman analysis, linear regression analysis, 95% CI, p 5 .58)%; end-diastolic volume ranged from 49.6 to 178.2 (87+-27.8) ml; end-systolic volume ranged from 11.4 to 78 (33.1+-13.6) ml. CT scan measurements: LVEF ranged from 53 to 86% (67.8+-7.78); end-diastolic volume ranged from 51 to 186 (106.5+-30.3) ml; end-systolic volume ranged from 7 to 72 (35.5+-13.4)ml. Correlations between RT-3D-Echo and CT were: LVEF (r: 0.7888, p<0.0001, 95% CI 0.6301 to 0.8843); end-diastolic volume (r: 0.7695, p<0.0001, 95% CI 0.5995 to 0.8730); end-systolic volume (r: 0.8119, p<0.0001, 95% CI 0.6673 to 0.8975). Conclusion: Good correlation between LVEF and ventricular volume parameters as measured by RT-3D-Echo and 64-slice ultrafast CT was found in the present case series. (author)

  2. Fast precalculated triangular mesh algorithm for 3D binary computer-generated holograms.

    Science.gov (United States)

    Yang, Fan; Kaczorowski, Andrzej; Wilkinson, Tim D

    2014-12-10

    A new method for constructing computer-generated holograms using a precalculated triangular mesh is presented. The speed of calculation can be increased dramatically by exploiting both the precalculated base triangle and GPU parallel computing. Unlike algorithms using point-based sources, this method can reconstruct a more vivid 3D object instead of a "hollow image." In addition, there is no need to do a fast Fourier transform for each 3D element every time. A ferroelectric liquid crystal spatial light modulator is used to display the binary hologram within our experiment and the hologram of a base right triangle is produced by utilizing just a one-step Fourier transform in the 2D case, which can be expanded to the 3D case by multiplying by a suitable Fresnel phase plane. All 3D holograms generated in this paper are based on Fresnel propagation; thus, the Fresnel plane is treated as a vital element in producing the hologram. A GeForce GTX 770 graphics card with 2 GB memory is used to achieve parallel computing.

  3. Evaluation of pharyngeal volume and compliance of OSAHS patients using 3D CT and volume measurement

    International Nuclear Information System (INIS)

    Lan, Zhijie

    2004-01-01

    The intrinsic properties such as baseline caliber and compliance of the upper airway are thought to be important in the pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS).The author attempted using imaging methods to evaluate both baseline caliber and compliance in normal individuals and OSAHS patients, and to localize the obstructive sites in OSAHS patients. Critical closing pressure (P crit ) and minimally effective therapeutical pressure (P eff ) were measured and computed tomography (CT) scan of pharynx was performed during wakefulness and drug-induced sleep with P crit , 0 cm H 2 O and P eff being given through a nose mask system. 7 normal individuals (age, 32.2±6.5 y's and body mass index, 23.6±5.4 kg/m 2 ) and 13 OSAHS patients (age, 33.3±6.4 y's and body mass index, 25.9±6.0 kg/m 2 ) were studied. 3D images of pharyngeal airway were reconstructed, and volume of each subdivision of pharynx was measured. Volume, average area and compliance of each subdivision were compared between the two groups. On an air-mode view of 3D image, the outline of pharynx was shown as transparent tubal structure, on which the narrowing collapse of airway at any level or any direction can be easily identified. Anatomy of pharynx could be easily understood on the virtual endoscopic mode. During wakefulness, the average area of the upper (1.20±0.26 cm 2 vs. 1.57±0.17 cm 2 , P 2 vs. 2.58±0.27 cm 2 , P 2 vs. 1.45±0.18 cm 2 , P 2 vs. 2.44±0.26 cm 2 ). The compliance of the middle part (0.28±0.15/cmH 2 O vs. 0.13±0.07/cmH 2 O, P<0.05) of pharynx was significantly higher in OSAHS patients than in normal individuals. The data suggested that OSAHS patients have a narrower and more collapsible pharynx compared to the normal subjects. The method of the present study is valid to evaluate both morphology and function of the upper airway. (author)

  4. Theoretical prediction of fast 3D AC electro-osmotic pumps.

    Science.gov (United States)

    Bazant, Martin Z; Ben, Yuxing

    2006-11-01

    AC electro-osmotic (ACEO) pumps in microfluidics currently involve planar electrode arrays, but recent work on the underlying phenomenon of induced-charge electro-osmosis (ICEO) suggests that three-dimensional (3D) geometries may be exploited to achieve faster flows. In this paper, we present some new design principles for periodic 3D ACEO pumps, such as the "fluid conveyor belt" of ICEO flow over a stepped electrode array. Numerical simulations of these designs (using the standard low-voltage model) predict flow rates almost twenty times faster than existing planar ACEO pumps, for the same applied voltage and minimum feature size. These pumps may enable new portable or implantable lab-on-a-chip devices, since rather fast (mm s(-1)), tuneable flows should be attainable with battery voltages (<10 V).

  5. The evaluation of gallbladder contractibility for volume measurement by helical 3D-CT-cholangiography

    International Nuclear Information System (INIS)

    Hanaguri, Katsuro; Kimura, Hideaki; Kayashima, Yasuyo; Suemoto, Kouichiro; Makihata, Hiroshi; Maruhashi, Akira; Ohya, Toshihide; Ito, Katsuhide; Shen, Yun.

    1997-01-01

    As a new application of helical (spiral) scan, volume measurement has received a significant interest. Although it is important to evaluate gallbladder contractibility to decide on a treatment plan for a gallbladder lesion, qualitative analysis of gallbladder contractibility is very difficult owing to the fact that the volume of gallbladder can not be measured using usual DIC examination (plain X-P and tomography). In this study, the accuracy of volume measurement of helical CT was checked firstly by gallbladder phantom experiments. Then 128 cases of volume measurement of helical 3D CT Cholangiography (DIC-CT) were performed. Under the conditions of optimized scan technique (3 mm TH, 3 mm/s, 1 mm recon interval, Hispeed, GEMS), the difference of contractibility was obtained between clinical cases with and without thick wall. The experiment has shown that helical 3D CT volume measurement is very simple and highly accurate method which is useful for the evaluation of gallbladder contractibility. (author)

  6. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    Science.gov (United States)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  7. A fast rebinning algorithm for 3D positron emission tomography using John's equation

    Science.gov (United States)

    Defrise, Michel; Liu, Xuan

    1999-08-01

    Volume imaging in positron emission tomography (PET) requires the inversion of the three-dimensional (3D) x-ray transform. The usual solution to this problem is based on 3D filtered-backprojection (FBP), but is slow. Alternative methods have been proposed which factor the 3D data into independent 2D data sets corresponding to the 2D Radon transforms of a stack of parallel slices. Each slice is then reconstructed using 2D FBP. These so-called rebinning methods are numerically efficient but are approximate. In this paper a new exact rebinning method is derived by exploiting the fact that the 3D x-ray transform of a function is the solution to the second-order partial differential equation first studied by John. The method is proposed for two sampling schemes, one corresponding to a pair of infinite plane detectors and another one corresponding to a cylindrical multi-ring PET scanner. The new FORE-J algorithm has been implemented for this latter geometry and was compared with the approximate Fourier rebinning algorithm FORE and with another exact rebinning algorithm, FOREX. Results with simulated data demonstrate a significant improvement in accuracy compared to FORE, while the reconstruction time is doubled. Compared to FOREX, the FORE-J algorithm is slightly less accurate but more than three times faster.

  8. Fast 3D magnetic resonance fingerprinting for a whole-brain coverage.

    Science.gov (United States)

    Ma, Dan; Jiang, Yun; Chen, Yong; McGivney, Debra; Mehta, Bhairav; Gulani, Vikas; Griswold, Mark

    2018-04-01

    The purpose of this study was to accelerate the acquisition and reconstruction time of 3D magnetic resonance fingerprinting scans. A 3D magnetic resonance fingerprinting scan was accelerated by using a single-shot spiral trajectory with an undersampling factor of 48 in the x-y plane, and an interleaved sampling pattern with an undersampling factor of 3 through plane. Further acceleration came from reducing the waiting time between neighboring partitions. The reconstruction time was accelerated by applying singular value decomposition compression in k-space. Finally, a 3D premeasured B 1 map was used to correct for the B 1 inhomogeneity. The T 1 and T 2 values of the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI phantom showed a good agreement with the standard values, with an average concordance correlation coefficient of 0.99, and coefficient of variation of 7% in the repeatability scans. The results from in vivo scans also showed high image quality in both transverse and coronal views. This study applied a fast acquisition scheme for a fully quantitative 3D magnetic resonance fingerprinting scan with a total acceleration factor of 144 as compared with the Nyquist rate, such that 3D T 1 , T 2 , and proton density maps can be acquired with whole-brain coverage at clinical resolution in less than 5 min. Magn Reson Med 79:2190-2197, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  9. Study of 3D visualization of fast active reflector based on openGL and EPICS

    International Nuclear Information System (INIS)

    Luo Mingcheng; Wu Wenqing; Liu Jiajing; Tang Pengyi; Wang Jian

    2014-01-01

    Active Reflector is the one of the innovations of Five hundred meter Aperture Spherical Telescope (FAST). Its performance will influence the performance of whole telescope and for display all status of ARS in real time, the EPICS (Experimental Physics and Industrial Control System) is used to develop the control system of ARS and virtual 3D technology-OpenGL is used to visualize the status. For the real-time performance of EPICS, the status visualization is also display in real time for users to improve the efficiency of telescope observing. (authors)

  10. Fast readout logic interfacing a 256-pixel matrix of a dual-layer 3D device

    International Nuclear Information System (INIS)

    Gabrielli, A; Giorgi, F; Villa, M; Morsani, F

    2010-01-01

    A prototype of a 3D ASIC built up of a fast readout architecture, with sparsification capabilities, which interfaces with a matrix of a 256-pixel sensor, was recently submitted. The chosen technology is CMOS Chartered 130 nm as it is compatible with the Tezzaron facility to interconnect face-to-face two silicon wafers allowing for a vertical integration structure by means of through-silicon-vias. Particularly, the readout logic uses one layer that will be stacked on a sensor layer at the end of the fabrication process.

  11. Fast readout logic interfacing a 256-pixel matrix of a dual-layer 3D device

    Energy Technology Data Exchange (ETDEWEB)

    Gabrielli, A; Giorgi, F; Villa, M [INFN-Bologna and Physics Department, University of Bologna, Viale Berti Pichat, 6/2, 40127, Bologna (Italy); Morsani, F, E-mail: alessandro.gabrielli@bo.infn.i [INFN-Pisa and University of Pisa, Largo B. Pontecorvo, 3, 56127, Pisa (Italy)

    2010-07-15

    A prototype of a 3D ASIC built up of a fast readout architecture, with sparsification capabilities, which interfaces with a matrix of a 256-pixel sensor, was recently submitted. The chosen technology is CMOS Chartered 130 nm as it is compatible with the Tezzaron facility to interconnect face-to-face two silicon wafers allowing for a vertical integration structure by means of through-silicon-vias. Particularly, the readout logic uses one layer that will be stacked on a sensor layer at the end of the fabrication process.

  12. 3D fast adaptive correlation imaging for large-scale gravity data based on GPU computation

    Science.gov (United States)

    Chen, Z.; Meng, X.; Guo, L.; Liu, G.

    2011-12-01

    In recent years, large scale gravity data sets have been collected and employed to enhance gravity problem-solving abilities of tectonics studies in China. Aiming at the large scale data and the requirement of rapid interpretation, previous authors have carried out a lot of work, including the fast gradient module inversion and Euler deconvolution depth inversion ,3-D physical property inversion using stochastic subspaces and equivalent storage, fast inversion using wavelet transforms and a logarithmic barrier method. So it can be say that 3-D gravity inversion has been greatly improved in the last decade. Many authors added many different kinds of priori information and constraints to deal with nonuniqueness using models composed of a large number of contiguous cells of unknown property and obtained good results. However, due to long computation time, instability and other shortcomings, 3-D physical property inversion has not been widely applied to large-scale data yet. In order to achieve 3-D interpretation with high efficiency and precision for geological and ore bodies and obtain their subsurface distribution, there is an urgent need to find a fast and efficient inversion method for large scale gravity data. As an entirely new geophysical inversion method, 3D correlation has a rapid development thanks to the advantage of requiring no a priori information and demanding small amount of computer memory. This method was proposed to image the distribution of equivalent excess masses of anomalous geological bodies with high resolution both longitudinally and transversely. In order to tranform the equivalence excess masses into real density contrasts, we adopt the adaptive correlation imaging for gravity data. After each 3D correlation imaging, we change the equivalence into density contrasts according to the linear relationship, and then carry out forward gravity calculation for each rectangle cells. Next, we compare the forward gravity data with real data, and

  13. 2D-3D Registration of CT Vertebra Volume to Fluoroscopy Projection: A Calibration Model Assessment

    Directory of Open Access Journals (Sweden)

    P. Bifulco

    2010-01-01

    Full Text Available This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1 mm for displacements parallel to the fluoroscopic plane, and of order of 10 mm for the orthogonal displacement.

  14. Estimation of the 3D positioning of anatomic structures from radiographic projection and volume knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Bifulco, P; Cesarelli, M; Roccasalva Firenze, M; Verso, E; Sansone, M; Bracale, M [University of Naples, Federico II, Electronic Engineering Department, Bioengineering Unit, Via Claudio, 21 - 80125 Naples (Italy)

    1999-12-31

    The aim of this study is to develop a method to estimate the 3D positioning of an anatomic structure using the knowledge of its volume (provided by CT or MRI) combined with a single radiographic projection. This method could be applied in stereotactic surgery or in the study of 3D body joints kinematics. The knowledge of the 3D anatomical structure, available from CT (or in future MRI) is used to estimate the orientation of the projection that better match the actual 2D available projection. For this purpose it was necessary to develop an algorithm to simulate the radiographic projections. The radiographic image formation process has been simulated utilizing the geometrical characteristics of a real radiographic device and the volumetric anatomical data of the patient, obtained by 3D diagnostic CT images. The position of the patient volume respect to the radiological device is estimated comparing the actual radiographic projection with those simulated, maximising a similarity index. To assess the estimation, the 3D positioning of a segmented vertebra has been used as a test volume. The assessment has been carried out only by means of simulation. Estimation errors have been statistically evaluated. Conditions of mispositioning and noise have been also considered. The results relative to the simulation show the feasibility of the method. From the analysis of the errors emerges that the searching procedure results robust respect to the addition of white Gaussian noise. (authors) 13 fers., 4 figs., 1 tabs.

  15. Estimation of the 3D positioning of anatomic structures from radiographic projection and volume knowledge

    International Nuclear Information System (INIS)

    Bifulco, P.; Cesarelli, M.; Roccasalva Firenze, M.; Verso, E.; Sansone, M.; Bracale, M.

    1998-01-01

    The aim of this study is to develop a method to estimate the 3D positioning of an anatomic structure using the knowledge of its volume (provided by CT or MRI) combined with a single radiographic projection. This method could be applied in stereotactic surgery or in the study of 3D body joints kinematics. The knowledge of the 3D anatomical structure, available from CT (or in future MRI) is used to estimate the orientation of the projection that better match the actual 2D available projection. For this purpose it was necessary to develop an algorithm to simulate the radiographic projections. The radiographic image formation process has been simulated utilizing the geometrical characteristics of a real radiographic device and the volumetric anatomical data of the patient, obtained by 3D diagnostic CT images. The position of the patient volume respect to the radiological device is estimated comparing the actual radiographic projection with those simulated, maximising a similarity index. To assess the estimation, the 3D positioning of a segmented vertebra has been used as a test volume. The assessment has been carried out only by means of simulation. Estimation errors have been statistically evaluated. Conditions of mispositioning and noise have been also considered. The results relative to the simulation show the feasibility of the method. From the analysis of the errors emerges that the searching procedure results robust respect to the addition of white Gaussian noise. (authors)

  16. Reconstruction of the 3D representative volume element from the generalized two-point correlation function

    International Nuclear Information System (INIS)

    Staraselski, Y; Brahme, A; Inal, K; Mishra, R K

    2015-01-01

    This paper presents the first application of three-dimensional (3D) cross-correlation microstructure reconstruction implemented for a representative volume element (RVE) to facilitate the microstructure engineering of materials. This has been accomplished by developing a new methodology for reconstructing 3D microstructure using experimental two-dimensional electron backscatter diffraction data. The proposed methodology is based on the analytical representation of the generalized form of the two-point correlation function—the distance-disorientation function (DDF). Microstructure reconstruction is accomplished by extending the simulated annealing techniques to perform three term reconstruction with a minimization of the DDF. The new 3D microstructure reconstruction algorithm is employed to determine the 3D RVE containing all of the relevant microstructure information for accurately computing the mechanical response of solids, especially when local microstructural variations influence the global response of the material as in the case of fracture initiation. (paper)

  17. Fast fluid-attenuated inversion-recovery imaging: first experience with a 3D version in epilepsy

    International Nuclear Information System (INIS)

    Wieshmann, U.C.; Symms, M.R.; Bartlett, P.A.; Shorvon, S.D.; Barker, G.J.; Stevens, J.M.

    1998-01-01

    We developed a 3D version of fast fluid-attenuated inversion-recovery imaging (FLAIR) which provides images with a slice thickness of 1.5 mm. We present our initial experience with 3D fast FLAIR in patients with epilepsy. We compared 3D fast FLAIR (slice thickness 1.5 mm), 2D fast FLAIR (slice thickness 5 mm) and a 3D spoiled GRASS (IRSPGR) sequence (slice thickness 1.5 mm) in 10 patients with lesional epilepsy (head injury 1, hippocampal sclerosis 2, low-grade glioma 2, dysembryoplastic neuroepithelial tumour 2, polymicrogyria 1, perinatal infarct 1 and presumed thrombosed aneurysm 1). Both 2D and 3D fast FLAIR sequences yielded higher conspicuity for lesions than the T1-weighted IRSPGR sequence, except in the patient with polymicrogyria. The extent of the lesion, in particular that of low-grade tumours, was best assessed on 3D fast FLAIR images. 3D fast FLAIR may be a useful additional tool especially for imaging low-grade tumours. (orig.)

  18. Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies.

    Science.gov (United States)

    Sanz-Requena, Roberto; Moratal, David; García-Sánchez, Diego Ramón; Bodí, Vicente; Rieta, José Joaquín; Sanchis, Juan Manuel

    2007-03-01

    Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media-adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media-adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made. The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1mm(2) (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5mm(3) (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.

  19. Advantages and disadvantages of 3D ultrasound of thyroid nodules including thin slice volume rendering

    Directory of Open Access Journals (Sweden)

    Slapa Rafal

    2011-01-01

    Full Text Available Abstract Background The purpose of this study was to assess the advantages and disadvantages of 3D gray-scale and power Doppler ultrasound, including thin slice volume rendering (TSVR, applied for evaluation of thyroid nodules. Methods The retrospective evaluation by two observers of volumes of 71 thyroid nodules (55 benign, 16 cancers was performed using a new TSVR technique. Dedicated 4D ultrasound scanner with an automatic 6-12 MHz 4D probe was used. Statistical analysis was performed with Stata v. 8.2. Results Multiple logistic regression analysis demonstrated that independent risk factors of thyroid cancers identified by 3D ultrasound include: (a ill-defined borders of the nodule on MPR presentation, (b a lobulated shape of the nodule in the c-plane and (c a density of central vessels in the nodule within the minimal or maximal ranges. Combination of features provided sensitivity 100% and specificity 60-69% for thyroid cancer. Calcification/microcalcification-like echogenic foci on 3D ultrasound proved not to be a risk factor of thyroid cancer. Storage of the 3D data of the whole nodules enabled subsequent evaluation of new parameters and with new rendering algorithms. Conclusions Our results indicate that 3D ultrasound is a practical and reproducible method for the evaluation of thyroid nodules. 3D ultrasound stores volumes comprising the whole lesion or organ. Future detailed evaluations of the data are possible, looking for features that were not fully appreciated at the time of collection or applying new algorithms for volume rendering in order to gain important information. Three-dimensional ultrasound data could be included in thyroid cancer databases. Further multicenter large scale studies are warranted.

  20. Whole object surface area and volume of partial-view 3D models

    International Nuclear Information System (INIS)

    Mulukutla, Gopal K; Proussevitch, Alexander A; Genareau, Kimberly D; Durant, Adam J

    2017-01-01

    Micro-scale 3D models, important components of many studies in science and engineering, are often used to determine morphological characteristics such as shape, surface area and volume. The application of techniques such as stereoscopic scanning electron microscopy on whole objects often results in ‘partial-view’ models with a portion of object not within the field of view thus not captured in the 3D model. The nature and extent of the surface not captured is dependent on the complex interaction of imaging system attributes (e.g. working distance, viewing angle) with object size, shape and morphology. As a result, any simplistic assumptions in estimating whole object surface area or volume can lead to significant errors. In this study, we report on a novel technique to estimate the physical fraction of an object captured in a partial-view 3D model of an otherwise whole object. This allows a more accurate estimate of surface area and volume. Using 3D models, we demonstrate the robustness of this method and the accuracy of surface area and volume estimates relative to true values. (paper)

  1. 3D automatic segmentation method for retinal optical coherence tomography volume data using boundary surface enhancement

    Directory of Open Access Journals (Sweden)

    Yankui Sun

    2016-03-01

    Full Text Available With the introduction of spectral-domain optical coherence tomography (SD-OCT, much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a boundary surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced boundary surface, where pixel intensity, boundary position information, and intensity changes on both sides of the boundary surface are used simultaneously. Next, preliminary discrete boundary points are detected from the A-Scans of the volume data. Finally, surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed boundary surface by correcting a small number of error points. Our method can extract retinal layer boundary surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of 496×512 (each B-Scan comprising 512 A-Scans containing 496 pixels; experimental results show that this method can accurately segment seven layer boundary surfaces in normal as well as some abnormal eyes.

  2. 3D prostate TRUS segmentation using globally optimized volume-preserving prior.

    Science.gov (United States)

    Qiu, Wu; Rajchl, Martin; Guo, Fumin; Sun, Yue; Ukwatta, Eranga; Fenster, Aaron; Yuan, Jing

    2014-01-01

    An efficient and accurate segmentation of 3D transrectal ultrasound (TRUS) images plays an important role in the planning and treatment of the practical 3D TRUS guided prostate biopsy. However, a meaningful segmentation of 3D TRUS images tends to suffer from US speckles, shadowing and missing edges etc, which make it a challenging task to delineate the correct prostate boundaries. In this paper, we propose a novel convex optimization based approach to extracting the prostate surface from the given 3D TRUS image, while preserving a new global volume-size prior. We, especially, study the proposed combinatorial optimization problem by convex relaxation and introduce its dual continuous max-flow formulation with the new bounded flow conservation constraint, which results in an efficient numerical solver implemented on GPUs. Experimental results using 12 patient 3D TRUS images show that the proposed approach while preserving the volume-size prior yielded a mean DSC of 89.5% +/- 2.4%, a MAD of 1.4 +/- 0.6 mm, a MAXD of 5.2 +/- 3.2 mm, and a VD of 7.5% +/- 6.2% in - 1 minute, deomonstrating the advantages of both accuracy and efficiency. In addition, the low standard deviation of the segmentation accuracy shows a good reliability of the proposed approach.

  3. First impressions of 3D visual tools and dose volume histograms for plan evaluation

    International Nuclear Information System (INIS)

    Rattray, G.; Simitcioglu, A.; Parkinson, M.; Biggs, J.

    1999-01-01

    Converting from 2D to 3D treatment planning offers numerous challenges. The practices that have evolved in the 2D environment may not be applicable when translated into the 3D environment. One such practice is the methods used to evaluate a plan. In 2D planning a plane by plane comparison method is generally practiced. This type of evaluation method would not be appropriate for plans produced by a 3D planning system. To this end 3D dose displays and Dose Volume Histograms (DVHs) have been developed to facilitate the evaluation of such plans. A survey was conducted to determine the impressions of Radiation Therapists as they used these tools for the first time. The survey involved comparing a number of plans for a small group of patients and selecting the best plan for each patient. Three evaluation methods were assessed. These included the traditional plane by plane, 3D dose display, and DVHs. Those surveyed found the DVH to be the easiest of the three methods to use, with the 3D display being the next easiest. Copyright (1999) Blackwell Science Pty Ltd

  4. Efficient 3D Volume Reconstruction from a Point Cloud Using a Phase-Field Method

    Directory of Open Access Journals (Sweden)

    Darae Jeong

    2018-01-01

    Full Text Available We propose an explicit hybrid numerical method for the efficient 3D volume reconstruction from unorganized point clouds using a phase-field method. The proposed three-dimensional volume reconstruction algorithm is based on the 3D binary image segmentation method. First, we define a narrow band domain embedding the unorganized point cloud and an edge indicating function. Second, we define a good initial phase-field function which speeds up the computation significantly. Third, we use a recently developed explicit hybrid numerical method for solving the three-dimensional image segmentation model to obtain efficient volume reconstruction from point cloud data. In order to demonstrate the practical applicability of the proposed method, we perform various numerical experiments.

  5. 3D imaging of the mitochondrial redox state of rat hearts under normal and fasting conditions

    Directory of Open Access Journals (Sweden)

    He N. Xu

    2014-03-01

    Full Text Available The heart requires continuous ATP availability that is generated in the mitochondria. Although studies using the cell culture and perfused organ models have been carried out to investigate the biochemistry in the mitochondria in response to a change in substrate supply, mitochondrial bioenergetics of heart under normal feed or fasting conditions has not been studied at the tissue level with a sub-millimeter spatial resolution either in vivo or ex vivo. Oxidation of many food-derived metabolites to generate ATP in the mitochondria is realized through the NADH/NAD+ couple acting as a central electron carrier. We employed the Chance redox scanner — the low-temperature fluorescence scanner to image the three-dimensional (3D spatial distribution of the mitochondrial redox states in heart tissues of rats under normal feeding or an overnight starvation for 14.5 h. Multiple consecutive sections of each heart were imaged to map three redox indices, i.e., NADH, oxidized flavoproteins (Fp, including flavin adenine dinucleotide (FAD and the redox ratio NADH/Fp. The imaging results revealed the micro-heterogeneity and the spatial distribution of these redox indices. The quantitative analysis showed that in the fasted hearts the standard deviation of both NADH and Fp, i.e., SD_NADH and SD_Fp, significantly decreased with a p value of 0.032 and 0.045, respectively, indicating that the hearts become relatively more homogeneous after fasting. The fasted hearts contained 28.6% less NADH (p = 0.038. No significant change in Fp was found (p = 0.4. The NADH/Fp ratio decreased with a marginal p value (0.076. The decreased NADH in the fasted hearts is consistent with the cardiac cells' reliance of fatty acids consumption for energy metabolism when glucose becomes scarce. The experimental observation of NADH decrease induced by dietary restriction in the heart at tissue level has not been reported to our best knowledge. The Chance redox scanner demonstrated the

  6. 3D IMAGING OF THE MITOCHONDRIAL REDOX STATE OF RAT HEARTS UNDER NORMAL AND FASTING CONDITIONS.

    Science.gov (United States)

    Xu, He N; Zhou, Rong; Moon, Lily; Feng, Min; Li, Lin Z

    2014-03-01

    The heart requires continuous ATP availability that is generated in the mitochondria. Although studies using the cell culture and perfused organ models have been carried out to investigate the biochemistry in the mitochondria in response to a change in substrate supply, mitochondrial bioenergetics of heart under normal feed or fasting conditions has not been studied at the tissue level with a sub-millimeter spatial resolution either in vivo or ex vivo . Oxidation of many food-derived metabolites to generate ATP in the mitochondria is realized through the NADH/NAD + couple acting as a central electron carrier. We employed the Chance redox scanner - the low-temperature fluorescence scanner to image the three-dimensional (3D) spatial distribution of the mitochondrial redox states in heart tissues of rats under normal feeding or an overnight starvation for 14.5 h. Multiple consecutive sections of each heart were imaged to map three redox indices, i.e., NADH, oxidized flavoproteins (Fp, including flavin adenine dinucleotide (FAD)) and the redox ratio NADH/Fp. The imaging results revealed the micro-heterogeneity and the spatial distribution of these redox indices. The quantitative analysis showed that in the fasted hearts the standard deviation of both NADH and Fp, i.e., SD_NADH and SD_Fp, significantly decreased with a p value of 0.032 and 0.045, respectively, indicating that the hearts become relatively more homogeneous after fasting. The fasted hearts contained 28.6% less NADH ( p = 0.038). No significant change in Fp was found ( p = 0.4). The NADH/Fp ratio decreased with a marginal p value (0.076). The decreased NADH in the fasted hearts is consistent with the cardiac cells' reliance of fatty acids consumption for energy metabolism when glucose becomes scarce. The experimental observation of NADH decrease induced by dietary restriction in the heart at tissue level has not been reported to our best knowledge. The Chance redox scanner demonstrated the feasibility of 3D

  7. Kalisphera: an analytical tool to reproduce the partial volume effect of spheres imaged in 3D

    International Nuclear Information System (INIS)

    Tengattini, Alessandro; Andò, Edward

    2015-01-01

    In experimental mechanics, where 3D imaging is having a profound effect, spheres are commonly adopted for their simplicity and for the ease of their modeling. In this contribution we develop an analytical tool, ‘kalisphera’, to produce 3D raster images of spheres including their partial volume effect. This allows us to evaluate the metrological performance of existing image-based measurement techniques (knowing a priori the ground truth). An advanced application of ‘kalisphera’ is developed here to identify and accurately characterize spheres in real 3D x-ray tomography images with the objective of improving trinarization and contact detection. The effect of the common experimental imperfections is assessed and the overall performance of the tool tested on real images. (paper)

  8. Fast imaging of laboratory core floods using 3D compressed sensing RARE MRI.

    Science.gov (United States)

    Ramskill, N P; Bush, I; Sederman, A J; Mantle, M D; Benning, M; Anger, B C; Appel, M; Gladden, L F

    2016-09-01

    Three-dimensional (3D) imaging of the fluid distributions within the rock is essential to enable the unambiguous interpretation of core flooding data. Magnetic resonance imaging (MRI) has been widely used to image fluid saturation in rock cores; however, conventional acquisition strategies are typically too slow to capture the dynamic nature of the displacement processes that are of interest. Using Compressed Sensing (CS), it is possible to reconstruct a near-perfect image from significantly fewer measurements than was previously thought necessary, and this can result in a significant reduction in the image acquisition times. In the present study, a method using the Rapid Acquisition with Relaxation Enhancement (RARE) pulse sequence with CS to provide 3D images of the fluid saturation in rock core samples during laboratory core floods is demonstrated. An objective method using image quality metrics for the determination of the most suitable regularisation functional to be used in the CS reconstructions is reported. It is shown that for the present application, Total Variation outperforms the Haar and Daubechies3 wavelet families in terms of the agreement of their respective CS reconstructions with a fully-sampled reference image. Using the CS-RARE approach, 3D images of the fluid saturation in the rock core have been acquired in 16min. The CS-RARE technique has been applied to image the residual water saturation in the rock during a water-water displacement core flood. With a flow rate corresponding to an interstitial velocity of vi=1.89±0.03ftday(-1), 0.1 pore volumes were injected over the course of each image acquisition, a four-fold reduction when compared to a fully-sampled RARE acquisition. Finally, the 3D CS-RARE technique has been used to image the drainage of dodecane into the water-saturated rock in which the dynamics of the coalescence of discrete clusters of the non-wetting phase are clearly observed. The enhancement in the temporal resolution that has

  9. Multilevel fast multipole method based on a potential formulation for 3D electromagnetic scattering problems.

    Science.gov (United States)

    Fall, Mandiaye; Boutami, Salim; Glière, Alain; Stout, Brian; Hazart, Jerome

    2013-06-01

    A combination of the multilevel fast multipole method (MLFMM) and boundary element method (BEM) can solve large scale photonics problems of arbitrary geometry. Here, MLFMM-BEM algorithm based on a scalar and vector potential formulation, instead of the more conventional electric and magnetic field formulations, is described. The method can deal with multiple lossy or lossless dielectric objects of arbitrary geometry, be they nested, in contact, or dispersed. Several examples are used to demonstrate that this method is able to efficiently handle 3D photonic scatterers involving large numbers of unknowns. Absorption, scattering, and extinction efficiencies of gold nanoparticle spheres, calculated by the MLFMM, are compared with Mie's theory. MLFMM calculations of the bistatic radar cross section (RCS) of a gold sphere near the plasmon resonance and of a silica coated gold sphere are also compared with Mie theory predictions. Finally, the bistatic RCS of a nanoparticle gold-silver heterodimer calculated with MLFMM is compared with unmodified BEM calculations.

  10. 3-D seismic response of a base-isolated fast reactor

    International Nuclear Information System (INIS)

    Kitamura, S.; Morishita, M.; Iwata, K.

    1992-01-01

    This paper describes a 3-D response analysis methodology development and its application to a base-isolated fast breeder reactor (FBR) plant. At first, studies on application of a base-isolation system to an FBR plant were performed to identify a range of appropriate characteristics of the system. A response analysis method was developed based on mathematical models for the restoring force characteristics of several types of the systems. A series of shaking table tests using a small scale model was carried out to verify the analysis method. A good agreement was seen between the test and analysis results in terms of the horizontal and vertical responses. Parametric studies were then made to assess the effects of various factors which might be influential to the seismic response of the system. Moreover, the method was applied to evaluate three-dimensional response of the base-isolated FBR. (author)

  11. Fast and flexible 3D object recognition solutions for machine vision applications

    Science.gov (United States)

    Effenberger, Ira; Kühnle, Jens; Verl, Alexander

    2013-03-01

    In automation and handling engineering, supplying work pieces between different stages along the production process chain is of special interest. Often the parts are stored unordered in bins or lattice boxes and hence have to be separated and ordered for feeding purposes. An alternative to complex and spacious mechanical systems such as bowl feeders or conveyor belts, which are typically adapted to the parts' geometry, is using a robot to grip the work pieces out of a bin or from a belt. Such applications are in need of reliable and precise computer-aided object detection and localization systems. For a restricted range of parts, there exists a variety of 2D image processing algorithms that solve the recognition problem. However, these methods are often not well suited for the localization of randomly stored parts. In this paper we present a fast and flexible 3D object recognizer that localizes objects by identifying primitive features within the objects. Since technical work pieces typically consist to a substantial degree of geometric primitives such as planes, cylinders and cones, such features usually carry enough information in order to determine the position of the entire object. Our algorithms use 3D best-fitting combined with an intelligent data pre-processing step. The capability and performance of this approach is shown by applying the algorithms to real data sets of different industrial test parts in a prototypical bin picking demonstration system.

  12. 3D reconstruction from X-ray fluoroscopy for clinical veterinary medicine using differential volume rendering

    International Nuclear Information System (INIS)

    Khongsomboon, K.; Hamamoto, Kazuhiko; Kondo, Shozo

    2007-01-01

    3D reconstruction from ordinary X-ray equipment which is not CT or MRI is required in clinical veterinary medicine. Authors have already proposed a 3D reconstruction technique from X-ray photograph to present bone structure. Although the reconstruction is useful for veterinary medicine, the technique has two problems. One is about exposure of X-ray and the other is about data acquisition process. An x-ray equipment which is not special one but can solve the problems is X-ray fluoroscopy. Therefore, in this paper, we propose a method for 3D-reconstruction from X-ray fluoroscopy for clinical veterinary medicine. Fluoroscopy is usually used to observe a movement of organ or to identify a position of organ for surgery by weak X-ray intensity. Since fluoroscopy can output a observed result as movie, the previous two problems which are caused by use of X-ray photograph can be solved. However, a new problem arises due to weak X-ray intensity. Although fluoroscopy can present information of not only bone structure but soft tissues, the contrast is very low and it is very difficult to recognize some soft tissues. It is very useful to be able to observe not only bone structure but soft tissues clearly by ordinary X-ray equipment in the field of clinical veterinary medicine. To solve this problem, this paper proposes a new method to determine opacity in volume rendering process. The opacity is determined according to 3D differential coefficient of 3D reconstruction. This differential volume rendering can present a 3D structure image of multiple organs volumetrically and clearly for clinical veterinary medicine. This paper shows results of simulation and experimental investigation of small dog and evaluation by veterinarians. (author)

  13. High Productivity DRIE solutions for 3D-SiP and MEMS Volume Manufacturing

    International Nuclear Information System (INIS)

    Puech, M; Thevenoud, J M; Launay, N; Arnal, N; Godinat, P; Andrieu, B; Gruffat, J M

    2006-01-01

    Emerging 3D-SiP technologies and high volume MEMS applications require high productivity mass production DRIE systems. The Alcatel DRIE product range has recently been optimised to reach the highest process and hardware production performances. A study based on sub-micron high aspect ratio structures encountered in the most stringent 3D-SiP has been carried out. The optimization of the Bosch process parameters has resulted in ultra high silicon etch rates, with unrivalled uniformity and repeatability leading to excellent process. In parallel, most recent hardware and proprietary design optimization including vacuum pumping lines, process chamber, wafer chucks, pressure control system, gas delivery are discussed. These improvements have been monitored in a mass production environment for a mobile phone application. Field data analysis shows a significant reduction of cost of ownership thanks to increased throughput and much lower running costs. These benefits are now available for all 3D-SiP and high volume MEMS applications. The typical etched patterns include tapered trenches for CMOS imagers, through silicon via holes for die stacking, well controlled profile angle for 3D high precision inertial sensors, and large exposed area features for inkjet printer heads and Silicon microphones

  14. Characteristics of spondylotic myelopathy on 3D driven-equilibrium fast spin echo and 2D fast spin echo magnetic resonance imaging: a retrospective cross-sectional study.

    Science.gov (United States)

    Abdulhadi, Mike A; Perno, Joseph R; Melhem, Elias R; Nucifora, Paolo G P

    2014-01-01

    In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures. However, it is not yet clear whether 3D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2D fast spin echo sequences, adding time to the examination and potential discomfort to the patient. Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2D fast spin echo sequences. We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3D driven-equilibrium fast spin echo sequences and 2D fast spin echo sequences at the same scanning session. The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3D driven-equilibrium fast spin echo and 2D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions. Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3D driven-equilibrium fast spin echo sequences compared to 2D fast spin echo sequences. These findings suggest that 3D driven-equilibrium fast spin echo sequences do not need supplemental 2D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord.

  15. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods

    DEFF Research Database (Denmark)

    van der Kleij, Lisa A.; de Bresser, Jeroen; Hendrikse, Jeroen

    2018-01-01

    ObjectiveIn previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T-2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim...... of this study was to assess the precision of the BPV and ICV measurements of the CSF MRI sequence and to validate the CSF MRI sequence by comparison with 3D T-1-based brain segmentation methods.Materials and methodsTen healthy volunteers (2 females; median age 28 years) were scanned (3T MRI) twice......cc) and CSF HR (5 +/- 5/4 +/- 2cc) were comparable to FSL HR (9 +/- 11/19 +/- 23cc), FSL LR (7 +/- 4,6 +/- 5cc),FreeSurfer HR (5 +/- 3/14 +/- 8cc), FreeSurfer LR (9 +/- 8,12 +/- 10cc), and SPM HR (5 +/- 3/4 +/- 7cc), and SPM LR (5 +/- 4,5 +/- 3cc). The correlation between the measured volumes...

  16. Fast 3D Net Expeditions: Tools for Effective Scientific Collaboration on the World Wide Web

    Science.gov (United States)

    Watson, Val; Chancellor, Marisa K. (Technical Monitor)

    1996-01-01

    Two new technologies, the FASTexpedition and Remote FAST, have been developed that provide remote, 3D (three dimensional), high resolution, dynamic, interactive viewing of scientific data. The FASTexpedition permits one to access scientific data from the World Wide Web, take guided expeditions through the data, and continue with self controlled expeditions through the data. Remote FAST permits collaborators at remote sites to simultaneously view an analysis of scientific data being controlled by one of the collaborators. Control can be transferred between sites. These technologies are now being used for remote collaboration in joint university, industry, and NASA projects. Also, NASA Ames Research Center has initiated a project to make scientific data and guided expeditions through the data available as FASTexpeditions on the World Wide Web for educational purposes. Previously, remote visualization of dynamic data was done using video format (transmitting pixel information) such as video conferencing or MPEG (Motion Picture Expert Group) movies on the Internet. The concept for this new technology is to send the raw data (e.g., grids, vectors, and scalars) along with viewing scripts over the Internet and have the pixels generated by a visualization tool running on the viewers local workstation. The visualization tool that is currently used is FAST (Flow Analysis Software Toolkit). The advantages of this new technology over using video format are: (1) The visual is much higher in resolution (1280x1024 pixels with 24 bits of color) than typical video format transmitted over the network. (2) The form of the visualization can be controlled interactively (because the viewer is interactively controlling the visualization tool running on his workstation). (3) A rich variety of guided expeditions through the data can be included easily. (4) A capability is provided for other sites to see a visual analysis of one site as the analysis is interactively performed. Control of

  17. Assessment of glioma response to radiotherapy using 3D pulsed-continuous arterial spin labeling and 3D segmented volume

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Li, Jianrui; Diao, Qiang; Lin, YuanKai; Zhang, Jun; Li, Lin; Yang, Gang; Fang, Xiaokun; Li, Xie; Chen, YingQi; Zheng, Ling, E-mail: lingzheng1989@yeah.net; Lu, Guangming, E-mail: guangminglu1905@163.com

    2016-11-15

    Background: Gliomas are the most common primary brain tumors in adults, in some cases, radiotherapy may be the preferred treatment option especially for elderly people who cannot endure surgery. Therefore, it is necessary to evaluate the effects of radiotherapy on glioma. Arterial spin labeling (ASL) is an MR imaging technique that allows for a quantitative determination of cerebral blood flow (CBF) noninvasively. Tumor volume is still an important determinant for evaluating treatment response. The purpose of this study was to investigate the relationship between the tumor perfusion parameters and tumor volume and assess the effects of radiotherapy on glioma using pulsed-continuous arterial spin labeling (pcASL) technique. Methods: 35 patients with gliomas, histologically classified as low-grade group (n = 16) and high-grade group (n = 19), treated with radiotherapy only or before using other therapies were included in this study. MR examinations, including T1 weighted image and pcASL, were performed before and 4, 8, 12, 16 weeks after radiotherapy. Regional CBF of normal tissue, mean tumor blood flow (TBF{sub mean}), maximum tumor blood flow (TBF{sub max}), and tumor volume were evaluated at each time point. Both the percentage change in CBF (CBF ratio), TBF{sub mean} (TBF{sub mean} ratio), TBF{sub max} (TBF{sub max} ratio) and the percentage change in tumor volume (volume ratio) were calculated using values obtained before and after radiotherapy. The correlation between the volume ratio and CBF ratio, TBF{sub mean} ratio, TBF{sub max} ratio was assessed using linear regression analysis and Pearson’s correlation. Results: The TBF{sub mean} and TBF{sub max} of high-grade gliomas were significantly higher than that of low-grade group. In high-grade group, a strong correlation was demonstrated between the tumor volume and the TBF{sub max} before radiotherapy (R{sup 2} = 0.35, r{sub s} = 0.59, p < 0.05). There was also a significant correlation between the TBF

  18. A fast, accurate, and automatic 2D-3D image registration for image-guided cranial radiosurgery

    International Nuclear Information System (INIS)

    Fu Dongshan; Kuduvalli, Gopinath

    2008-01-01

    The authors developed a fast and accurate two-dimensional (2D)-three-dimensional (3D) image registration method to perform precise initial patient setup and frequent detection and correction for patient movement during image-guided cranial radiosurgery treatment. In this method, an approximate geometric relationship is first established to decompose a 3D rigid transformation in the 3D patient coordinate into in-plane transformations and out-of-plane rotations in two orthogonal 2D projections. Digitally reconstructed radiographs are generated offline from a preoperative computed tomography volume prior to treatment and used as the reference for patient position. A multiphase framework is designed to register the digitally reconstructed radiographs with the x-ray images periodically acquired during patient setup and treatment. The registration in each projection is performed independently; the results in the two projections are then combined and converted to a 3D rigid transformation by 2D-3D geometric backprojection. The in-plane transformation and the out-of-plane rotation are estimated using different search methods, including multiresolution matching, steepest descent minimization, and one-dimensional search. Two similarity measures, optimized pattern intensity and sum of squared difference, are applied at different registration phases to optimize accuracy and computation speed. Various experiments on an anthropomorphic head-and-neck phantom showed that, using fiducial registration as a gold standard, the registration errors were 0.33±0.16 mm (s.d.) in overall translation and 0.29 deg. ±0.11 deg. (s.d.) in overall rotation. The total targeting errors were 0.34±0.16 mm (s.d.), 0.40±0.2 mm (s.d.), and 0.51±0.26 mm (s.d.) for the targets at the distances of 2, 6, and 10 cm from the rotation center, respectively. The computation time was less than 3 s on a computer with an Intel Pentium 3.0 GHz dual processor

  19. Impact of Different CT Slice Thickness on Clinical Target Volume for 3D Conformal Radiation Therapy

    International Nuclear Information System (INIS)

    Prabhakar, Ramachandran; Ganesh, Tharmar; Rath, Goura K.; Julka, Pramod K.; Sridhar, Pappiah S.; Joshi, Rakesh C.; Thulkar, Sanjay

    2009-01-01

    The purpose of this study was to present the variation of clinical target volume (CTV) with different computed tomography (CT) slice thicknesses and the impact of CT slice thickness on 3-dimensional (3D) conformal radiotherapy treatment planning. Fifty patients with brain tumors were selected and CT scans with 2.5-, 5-, and 10-mm slice thicknesses were performed with non-ionic contrast enhancement. The patients were selected with tumor volume ranging from 2.54 cc to 222 cc. Three-dimensional treatment planning was performed for all three CT datasets. The target coverage and the isocenter shift between the treatment plans for different slice thickness were correlated with the tumor volume. An important observation from our study revealed that for volume 25 cc, the target underdosage was less than 6.7% for 5-mm slice thickness and 8% for 10-mm slice thickness. For 3D conformal radiotherapy treatment planning (3DCRT), a CT slice thickness of 2.5 mm is optimum for tumor volume 25 cc

  20. A fast algorithm for forward-modeling of gravitational fields in spherical coordinates with 3D Gauss-Legendre quadrature

    Science.gov (United States)

    Zhao, G.; Liu, J.; Chen, B.; Guo, R.; Chen, L.

    2017-12-01

    Forward modeling of gravitational fields at large-scale requires to consider the curvature of the Earth and to evaluate the Newton's volume integral in spherical coordinates. To acquire fast and accurate gravitational effects for subsurface structures, subsurface mass distribution is usually discretized into small spherical prisms (called tesseroids). The gravity fields of tesseroids are generally calculated numerically. One of the commonly used numerical methods is the 3D Gauss-Legendre quadrature (GLQ). However, the traditional GLQ integration suffers from low computational efficiency and relatively poor accuracy when the observation surface is close to the source region. We developed a fast and high accuracy 3D GLQ integration based on the equivalence of kernel matrix, adaptive discretization and parallelization using OpenMP. The equivalence of kernel matrix strategy increases efficiency and reduces memory consumption by calculating and storing the same matrix elements in each kernel matrix just one time. In this method, the adaptive discretization strategy is used to improve the accuracy. The numerical investigations show that the executing time of the proposed method is reduced by two orders of magnitude compared with the traditional method that without these optimized strategies. High accuracy results can also be guaranteed no matter how close the computation points to the source region. In addition, the algorithm dramatically reduces the memory requirement by N times compared with the traditional method, where N is the number of discretization of the source region in the longitudinal direction. It makes the large-scale gravity forward modeling and inversion with a fine discretization possible.

  1. Fast isotropic banding-free bSSFP imaging using 3D dynamically phase-cycled radial bSSFP (3D DYPR-SSFP)

    Energy Technology Data Exchange (ETDEWEB)

    Benkert, Thomas; Blaimer, Martin; Breuer, Felix A. [Research Center Magnetic Resonance Bavaria (MRB), Wuerzburg (Germany); Ehses, Philipp [Tuebingen Univ. (Germany). Dept. of Neuroimaging; Max Planck Institute for Biological Cybernetics, Tuebingen (Germany). High-Field MR Center; Jakob, Peter M. [Research Center Magnetic Resonance Bavaria (MRB), Wuerzburg (Germany); Wuerzburg Univ. (Germany). Dept. of Experimental Physics 5

    2016-05-01

    Aims: Dynamically phase-cycled radial balanced steady-state free precession (DYPR-SSFP) is a method for efficient banding artifact removal in bSSFP imaging. Based on a varying radiofrequency (RF) phase-increment in combination with a radial trajectory, DYPR-SSFP allows obtaining a banding-free image out of a single acquired k-space. The purpose of this work is to present an extension of this technique, enabling fast three-dimensional isotropic banding-free bSSFP imaging. Methods: While banding artifact removal with DYPR-SSFP relies on the applied dynamic phase-cycle, this aspect can lead to artifacts, at least when the number of acquired projections lies below a certain limit. However, by using a 3D radial trajectory with quasi-random view ordering for image acquisition, this problem is intrinsically solved, enabling 3D DYPR-SSFP imaging at or even below the Nyquist criterion. The approach is validated for brain and knee imaging at 3 Tesla. Results: Volumetric, banding-free images were obtained in clinically acceptable scan times with an isotropic resolution up to 0.56 mm. Conclusion: The combination of DYPR-SSFP with a 3D radial trajectory allows banding-free isotropic volumetric bSSFP imaging with no expense of scan time. Therefore, this is a promising candidate for clinical applications such as imaging of cranial nerves or articular cartilage.

  2. Common crus aplasia: diagnosis by 3D volume rendering imaging using 3DFT-CISS sequence

    International Nuclear Information System (INIS)

    Kim, H.J.; Song, J.W.; Chon, K.-M.; Goh, E.-K.

    2004-01-01

    AIM: The purpose of this study was to evaluate the findings of three-dimensional (3D) volume rendering (VR) imaging in common crus aplasia (CCA) of the inner ear. MATERIALS AND METHODS: Using 3D VR imaging of temporal bone constructive interference in steady state (CISS) magnetic resonance (MR) images, we retrospectively reviewed seven inner ears of six children who were candidates for cochlear implants and who had been diagnosed with CCA. As controls, we used the same method to examine 402 inner ears of 201 patients who had no clinical symptoms or signs of sensorineural hearing loss. Temporal bone MR imaging (MRI) was performed with a 1.5 T MR machine using a CISS sequence, and VR of the inner ear was performed on a work station. Morphological image analysis was performed on rotation views of 3D VR images. RESULTS: In all seven cases, CCA was diagnosed by the absence of the common crus. The remaining superior semicircular canal (SCC) was normal in five and hypoplastic in two inner ears, while the posterior SCC was normal in all seven. One patient showed bilateral symmetrical CCA. Complicated combined anomalies were seen in the cochlea, vestibule and lateral SCC. CONCLUSION: 3D VR imaging findings with MR CISS sequence can directly diagnose CCA. This technique may be useful in delineating detailed anomalies of SCCs

  3. Cell volume and geometric parameters determination in living cells using confocal microscopy and 3D reconstruction

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: David Hevia, Aida Rodriguez-Garcia, Marta Alonso-Gervós, Isabel Quirós-González, Henar M Cimadevilla, Carmen Gómez-Cordovés, Rosa M Sainz & Juan C Mayo ### Abstract The protocol reported here describes a simple, easy, fast and reproducible method aimed to know the geometric parameters of living cells based on confocal laser scanning microscopy combined with 3D reconstruction software. Briefly, the method is based on intrinsic fluorescence properties of acridine orange (AO), a...

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

    Energy Technology Data Exchange (ETDEWEB)

    Tornai, Gabor Janos; Cserey, Gyoergy [Faculty of Information Technology, Pazmany Peter Catholic University, Prater u. 50/a, H-1083, Budapest (Hungary); Pappas, Ion [General Electric Healthcare, Akron u. 2, H-2040, Budaoers (Hungary)

    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.

  5. Clinical Application of an Open-Source 3D Volume Rendering Software to Neurosurgical Approaches.

    Science.gov (United States)

    Fernandes de Oliveira Santos, Bruno; Silva da Costa, Marcos Devanir; Centeno, Ricardo Silva; Cavalheiro, Sergio; Antônio de Paiva Neto, Manoel; Lawton, Michael T; Chaddad-Neto, Feres

    2018-02-01

    Preoperative recognition of the anatomic individualities of each patient can help to achieve more precise and less invasive approaches. It also may help to anticipate potential complications and intraoperative difficulties. Here we describe the use, accuracy, and precision of a free tool for planning microsurgical approaches using 3-dimensional (3D) reconstructions from magnetic resonance imaging (MRI). We used the 3D volume rendering tool of a free open-source software program for 3D reconstruction of images of surgical sites obtained by MRI volumetric acquisition. We recorded anatomic reference points, such as the sulcus and gyrus, and vascularization patterns for intraoperative localization of lesions. Lesion locations were confirmed during surgery by intraoperative ultrasound and/or electrocorticography and later by postoperative MRI. Between August 2015 and September 2016, a total of 23 surgeries were performed using this technique for 9 low-grade gliomas, 7 high-grade gliomas, 4 cortical dysplasias, and 3 arteriovenous malformations. The technique helped delineate lesions with an overall accuracy of 2.6 ± 1.0 mm. 3D reconstructions were successfully performed in all patients, and images showed sulcus, gyrus, and venous patterns corresponding to the intraoperative images. All lesion areas were confirmed both intraoperatively and at the postoperative evaluation. With the technique described herein, it was possible to successfully perform 3D reconstruction of the cortical surface. This reconstruction tool may serve as an adjunct to neuronavigation systems or may be used alone when such a system is unavailable. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Fast Semantic Segmentation of 3d Point Clouds with Strongly Varying Density

    Science.gov (United States)

    Hackel, Timo; Wegner, Jan D.; Schindler, Konrad

    2016-06-01

    We describe an effective and efficient method for point-wise semantic classification of 3D point clouds. The method can handle unstructured and inhomogeneous point clouds such as those derived from static terrestrial LiDAR or photogammetric reconstruction; and it is computationally efficient, making it possible to process point clouds with many millions of points in a matter of minutes. The key issue, both to cope with strong variations in point density and to bring down computation time, turns out to be careful handling of neighborhood relations. By choosing appropriate definitions of a point's (multi-scale) neighborhood, we obtain a feature set that is both expressive and fast to compute. We evaluate our classification method both on benchmark data from a mobile mapping platform and on a variety of large, terrestrial laser scans with greatly varying point density. The proposed feature set outperforms the state of the art with respect to per-point classification accuracy, while at the same time being much faster to compute.

  7. Fast segmentation of stained nuclei in terabyte-scale, time resolved 3D microscopy image stacks.

    Directory of Open Access Journals (Sweden)

    Johannes Stegmaier

    Full Text Available Automated analysis of multi-dimensional microscopy images has become an integral part of modern research in life science. Most available algorithms that provide sufficient segmentation quality, however, are infeasible for a large amount of data due to their high complexity. In this contribution we present a fast parallelized segmentation method that is especially suited for the extraction of stained nuclei from microscopy images, e.g., of developing zebrafish embryos. The idea is to transform the input image based on gradient and normal directions in the proximity of detected seed points such that it can be handled by straightforward global thresholding like Otsu's method. We evaluate the quality of the obtained segmentation results on a set of real and simulated benchmark images in 2D and 3D and show the algorithm's superior performance compared to other state-of-the-art algorithms. We achieve an up to ten-fold decrease in processing times, allowing us to process large data sets while still providing reasonable segmentation results.

  8. Optimal noise reduction in 3D reconstructions of single particles using a volume-normalized filter

    Science.gov (United States)

    Sindelar, Charles V.; Grigorieff, Nikolaus

    2012-01-01

    The high noise level found in single-particle electron cryo-microscopy (cryo-EM) image data presents a special challenge for three-dimensional (3D) reconstruction of the imaged molecules. The spectral signal-to-noise ratio (SSNR) and related Fourier shell correlation (FSC) functions are commonly used to assess and mitigate the noise-generated error in the reconstruction. Calculation of the SSNR and FSC usually includes the noise in the solvent region surrounding the particle and therefore does not accurately reflect the signal in the particle density itself. Here we show that the SSNR in a reconstructed 3D particle map is linearly proportional to the fractional volume occupied by the particle. Using this relationship, we devise a novel filter (the “single-particle Wiener filter”) to minimize the error in a reconstructed particle map, if the particle volume is known. Moreover, we show how to approximate this filter even when the volume of the particle is not known, by optimizing the signal within a representative interior region of the particle. We show that the new filter improves on previously proposed error-reduction schemes, including the conventional Wiener filter as well as figure-of-merit weighting, and quantify the relationship between all of these methods by theoretical analysis as well as numeric evaluation of both simulated and experimentally collected data. The single-particle Wiener filter is applicable across a broad range of existing 3D reconstruction techniques, but is particularly well suited to the Fourier inversion method, leading to an efficient and accurate implementation. PMID:22613568

  9. 3D Finite Volume Modeling of ENDE Using Electromagnetic T-Formulation

    Directory of Open Access Journals (Sweden)

    Yue Li

    2012-01-01

    Full Text Available An improved method which can analyze the eddy current density in conductor materials using finite volume method is proposed on the basis of Maxwell equations and T-formulation. The algorithm is applied to solve 3D electromagnetic nondestructive evaluation (E’NDE benchmark problems. The computing code is applied to study an Inconel 600 work piece with holes or cracks. The impedance change due to the presence of the crack is evaluated and compared with the experimental data of benchmark problems No. 1 and No. 2. The results show a good agreement between both calculated and measured data.

  10. Virtual endoscopy and 3D volume rendering in the management of frontal sinus fractures.

    Science.gov (United States)

    Belina, Stanko; Cuk, Viseslav; Klapan, Ivica

    2009-12-01

    Frontal sinus fractures (FSF) are commonly caused by traffic accidents, assaults, industrial accidents and gunshot wounds. Classical roentgenography has high proportion of false negative findings in cases of FSF and is not particularly useful in examining the severity of damage to the frontal sinus posterior table and the nasofrontal duct region. High resolution computed tomography was inavoidable during the management of such patients but it may produce large quantity of 2D images. Postprocessing of datasets acquired by high resolution computer tomography from patients with severe head trauma may offer a valuable additional help in diagnostics and surgery planning. We performed virtual endoscopy (VE) and 3D volume rendering (3DVR) on high resolution CT data acquired from a 54-year-old man with with both anterior and posterior frontal sinus wall fracture in order to demonstrate advantages and disadvantages of these methods. Data acquisition was done by Siemens Somatom Emotion scanner and postprocessing was performed with Syngo 2006G software. VE and 3DVR were performed in a man who suffered blunt trauma to his forehead and nose in an traffic accident. Left frontal sinus anterior wall fracture without dislocation and fracture of tabula interna with dislocation were found. 3D position and orientation of fracture lines were shown in by 3D rendering software. We concluded that VE and 3DVR can clearly display the anatomic structure of the paranasal sinuses and nasopharyngeal cavity, revealing damage to the sinus wall caused by a fracture and its relationship to surrounding anatomical structures.

  11. Web-based volume slicer for 3D electron-microscopy data from EMDB.

    Science.gov (United States)

    Salavert-Torres, José; Iudin, Andrii; Lagerstedt, Ingvar; Sanz-García, Eduardo; Kleywegt, Gerard J; Patwardhan, Ardan

    2016-05-01

    We describe the functionality and design of the Volume slicer - a web-based slice viewer for EMDB entries. This tool uniquely provides the facility to view slices from 3D EM reconstructions along the three orthogonal axes and to rapidly switch between them and navigate through the volume. We have employed multiple rounds of user-experience testing with members of the EM community to ensure that the interface is easy and intuitive to use and the information provided is relevant. The impetus to develop the Volume slicer has been calls from the EM community to provide web-based interactive visualisation of 2D slice data. This would be useful for quick initial checks of the quality of a reconstruction. Again in response to calls from the community, we plan to further develop the Volume slicer into a fully-fledged Volume browser that provides integrated visualisation of EMDB and PDB entries from the molecular to the cellular scale. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  12. 3D CT modeling of hepatic vessel architecture and volume calculation in living donated liver transplantation

    International Nuclear Information System (INIS)

    Frericks, Bernd B.; Caldarone, Franco C.; Savellano, Dagmar Hoegemann; Stamm, Georg; Kirchhoff, Timm D.; Shin, Hoen-Oh; Galanski, Michael; Nashan, Bjoern; Klempnauer, Juergen; Schenk, Andrea; Selle, Dirk; Spindler, Wolf; Peitgen, Heinz-Otto

    2004-01-01

    The aim of this study was to evaluate a software tool for non-invasive preoperative volumetric assessment of potential donors in living donated liver transplantation (LDLT). Biphasic helical CT was performed in 56 potential donors. Data sets were post-processed using a non-commercial software tool for segmentation, volumetric analysis and visualisation of liver segments. Semi-automatic definition of liver margins allowed the segmentation of parenchyma. Hepatic vessels were delineated using a region-growing algorithm with automatically determined thresholds. Volumes and shapes of liver segments were calculated automatically based on individual portal-venous branches. Results were visualised three-dimensionally and statistically compared with conventional volumetry and the intraoperative findings in 27 transplanted cases. Image processing was easy to perform within 23 min. Of the 56 potential donors, 27 were excluded from LDLT because of inappropriate liver parenchyma or vascular architecture. Two recipients were not transplanted due to poor clinical conditions. In the 27 transplanted cases, preoperatively visualised vessels were confirmed, and only one undetected accessory hepatic vein was revealed. Calculated graft volumes were 1110±180 ml for right lobes, 820 ml for the left lobe and 270±30 ml for segments II+III. The calculated volumes and intraoperatively measured graft volumes correlated significantly. No significant differences between the presented automatic volumetry and the conventional volumetry were observed. A novel image processing technique was evaluated which allows a semi-automatic volume calculation and 3D visualisation of the different liver segments. (orig.)

  13. 3-D thermal hydraulic analysis of transient heat removal from fast reactor core using immersion coolers

    International Nuclear Information System (INIS)

    Chvetsov, I.; Volkov, A.

    2000-01-01

    For advanced fast reactors (EFR, BN-600M, BN-1600, CEFR) the special complementary loop is envisaged in order to ensure the decay heat removal from the core in the case of LOF accidents. This complementary loop includes immersion coolers that are located in the hot reactor plenum. To analyze the transient process in the reactor when immersion coolers come into operation one needs to involve 3-D thermal hydraulics code. Furthermore sometimes the problem becomes more complicated due to necessity of simulation of the thermal hydraulics processes into the core interwrapper space. For example on BN-600M and CEFR reactors it is supposed to ensure the effective removal of decay heat from core subassemblies by specially arranged internal circulation circuit: 'inter-wrapper space'. For thermal hydraulics analysis of the transients in the core and in the whole reactor including hot plenum with immersion coolers and considering heat and mass exchange between the main sodium flow and sodium that moves in the inter-wrapper space the code GRIFIC (the version of GRIF code family) was developed in IPPE. GRIFIC code was tested on experimental data obtained on RAMONA rig under conditions simulating decay heat removal of a reactor with the use of immersion coolers. Comparison has been made of calculated and experimental result, such as integral characteristics (flow rate through the core and water temperature at the core inlet and outlet) and the local temperatures (at thermocouple location) as well. In order to show the capabilities of the code some results of the transient analysis of heat removal from the core of BN-600M - type reactor under loss-of-flow accident are presented. (author)

  14. Algorithms for Fast Computing of the 3D-DCT Transform

    Directory of Open Access Journals (Sweden)

    S. Hanus

    2003-04-01

    Full Text Available The algorithm for video compression based on the Three-DimensionalDiscrete Cosine Transform (3D-DCT is presented. The original algorithmof the 3D-DCT has high time complexity. We propose several enhancementsto the original algorithm and make the calculation of the DCT algorithmfeasible for future real-time video compression.

  15. 3D ultrasound imaging : Fast and cost-effective morphometry of musculoskeletal tissue

    NARCIS (Netherlands)

    Weide, Guido; Van Der Zwaard, Stephan; Huijing, Peter A.; Jaspers, Richard T.; Harlaar, Jaap

    2017-01-01

    The developmental goal of 3D ultrasound imaging (3DUS) is to engineer a modality to perform 3D morphological ultrasound analysis of human muscles. 3DUS images are constructed from calibrated freehand 2D B-mode ultrasound images, which are positioned into a voxel array. Ultrasound (US) imaging allows

  16. Finding dose-volume constraints to reduce late rectal toxicity following 3D-conformal radiotherapy (3D-CRT) of prostate cancer

    International Nuclear Information System (INIS)

    Greco, Carlo; Mazzetta, Chiara; Cattani, Federica; Tosi, Giampiero; Castiglioni, Simona; Fodor, Andrei; Orecchia, Roberto

    2003-01-01

    Background and purpose: The rectum is known to display a dose-volume effect following high-dose 3D-conformal radiotherapy (3D-CRT). The aim of the study is to search for significant dose-volume combinations with the specific treatment technique and patient set-up currently used in our institution. Patients and methods: We retrospectively analyzed the dose-volume histograms (DVH) of 135 patients with stage T1b-T3b prostate cancer treated consecutively with 3D-CRT between 1996 and 2000 to a total dose of 76 Gy. The median follow-up was 28 months (range 12-62). All late rectal complications were scored using RTOG criteria. Time to late toxicity was assessed using the Kaplan-Meyer method. The association between variables at baseline and ≥2 rectal toxicity was tested using χ 2 test or Fisher's exact test. A multivariate analysis using logistic regression was performed. Results: Late rectal toxicity grade ≥2 was observed in 24 of the 135 patients (17.8%). A 'grey area' of increased risk has been identified. Average DVHs of the bleeding and non-bleeding patients were generated. The area under the percent volume DVH for the rectum of the bleeding patients was significantly higher than that of patients without late rectal toxicity. On multivariate analysis the correlation between the high risk DVHs and late rectal bleeding was confirmed. Conclusions: The present analysis confirms the role of the rectal DVH as a tool to discriminate patients undergoing high-dose 3D-CRT into a low and a high risk of developing late rectal bleeding. Based on our own results and taking into account the data published in the literature, we have been able to establish new dose-volume constraints for treatment planning: if possible, the percentage of rectal volume exposed to 40, 50, 60, 72 and 76 Gy should be limited to 60, 50, 25, 15 and 5%, respectively

  17. Enhanced FIB-SEM systems for large-volume 3D imaging

    Science.gov (United States)

    Xu, C Shan; Hayworth, Kenneth J; Lu, Zhiyuan; Grob, Patricia; Hassan, Ahmed M; García-Cerdán, José G; Niyogi, Krishna K; Nogales, Eva; Weinberg, Richard J; Hess, Harald F

    2017-01-01

    Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) can automatically generate 3D images with superior z-axis resolution, yielding data that needs minimal image registration and related post-processing. Obstacles blocking wider adoption of FIB-SEM include slow imaging speed and lack of long-term system stability, which caps the maximum possible acquisition volume. Here, we present techniques that accelerate image acquisition while greatly improving FIB-SEM reliability, allowing the system to operate for months and generating continuously imaged volumes > 106 µm3. These volumes are large enough for connectomics, where the excellent z resolution can help in tracing of small neuronal processes and accelerate the tedious and time-consuming human proofreading effort. Even higher resolution can be achieved on smaller volumes. We present example data sets from mammalian neural tissue, Drosophila brain, and Chlamydomonas reinhardtii to illustrate the power of this novel high-resolution technique to address questions in both connectomics and cell biology. DOI: http://dx.doi.org/10.7554/eLife.25916.001 PMID:28500755

  18. Liver Tumor Segmentation from MR Images Using 3D Fast Marching Algorithm and Single Hidden Layer Feedforward Neural Network

    Directory of Open Access Journals (Sweden)

    Trong-Ngoc Le

    2016-01-01

    Full Text Available Objective. Our objective is to develop a computerized scheme for liver tumor segmentation in MR images. Materials and Methods. Our proposed scheme consists of four main stages. Firstly, the region of interest (ROI image which contains the liver tumor region in the T1-weighted MR image series was extracted by using seed points. The noise in this ROI image was reduced and the boundaries were enhanced. A 3D fast marching algorithm was applied to generate the initial labeled regions which are considered as teacher regions. A single hidden layer feedforward neural network (SLFN, which was trained by a noniterative algorithm, was employed to classify the unlabeled voxels. Finally, the postprocessing stage was applied to extract and refine the liver tumor boundaries. The liver tumors determined by our scheme were compared with those manually traced by a radiologist, used as the “ground truth.” Results. The study was evaluated on two datasets of 25 tumors from 16 patients. The proposed scheme obtained the mean volumetric overlap error of 27.43% and the mean percentage volume error of 15.73%. The mean of the average surface distance, the root mean square surface distance, and the maximal surface distance were 0.58 mm, 1.20 mm, and 6.29 mm, respectively.

  19. Comparison of 2-D and 3-D estimates of placental volume in early pregnancy.

    Science.gov (United States)

    Aye, Christina Y L; Stevenson, Gordon N; Impey, Lawrence; Collins, Sally L

    2015-03-01

    Ultrasound estimation of placental volume (PlaV) between 11 and 13 wk has been proposed as part of a screening test for small-for-gestational-age babies. A semi-automated 3-D technique, validated against the gold standard of manual delineation, has been found at this stage of gestation to predict small-for-gestational-age at term. Recently, when used in the third trimester, an estimate obtained using a 2-D technique was found to correlate with placental weight at delivery. Given its greater simplicity, the 2-D technique might be more useful as part of an early screening test. We investigated if the two techniques produced similar results when used in the first trimester. The correlation between PlaV values calculated by the two different techniques was assessed in 139 first-trimester placentas. The agreement on PlaV and derived "standardized placental volume," a dimensionless index correcting for gestational age, was explored with the Mann-Whitney test and Bland-Altman plots. Placentas were categorized into five different shape subtypes, and a subgroup analysis was performed. Agreement was poor for both PlaV and standardized PlaV (p < 0.001 and p < 0.001), with the 2-D technique yielding larger estimates for both indices compared with the 3-D method. The mean difference in standardized PlaV values between the two methods was 0.007 (95% confidence interval: 0.006-0.009). The best agreement was found for regular rectangle-shaped placentas (p = 0.438 and p = 0.408). The poor correlation between the 2-D and 3-D techniques may result from the heterogeneity of placental morphology at this stage of gestation. In early gestation, the simpler 2-D estimates of PlaV do not correlate strongly with those obtained with the validated 3-D technique. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  20. Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology

    Science.gov (United States)

    Canavesi, Cristina; Cogliati, Andrea; Hayes, Adam; Santhanam, Anand P.; Tankam, Patrice; Rolland, Jannick P.

    2015-10-01

    Fast, robust, nondestructive 3D imaging is needed for characterization of microscopic structures in industrial and clinical applications. A custom micro-electromechanical system (MEMS)-based 2D scanner system was developed to achieve 55 kHz A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) instrument with a novel multilevel GPU architecture for high-speed imaging. GD-OCM yields high-definition volumetric imaging with dynamic depth of focusing through a bio-inspired liquid lens-based microscope design, which has no moving parts and is suitable for use in a manufacturing setting or in a medical environment. A dual-axis MEMS mirror was chosen to replace two single-axis galvanometer mirrors; as a result, the astigmatism caused by the mismatch between the optical pupil and the scanning location was eliminated and a 12x reduction in volume of the scanning system was achieved. Imaging at an invariant resolution of 2 μm was demonstrated throughout a volume of 1 × 1 × 0.6 mm3, acquired in less than 2 minutes. The MEMS-based scanner resulted in improved image quality, increased robustness and lighter weight of the system - all factors that are critical for on-field deployment. A custom integrated feedback system consisting of a laser diode and a position-sensing detector was developed to investigate the impact of the resonant frequency of the MEMS and the driving signal of the scanner on the movement of the mirror. Results on the metrology of manufactured materials and characterization of tissue samples with GD-OCM are presented.

  1. Extended volume and surface scatterometer for optical characterization of 3D-printed elements

    Science.gov (United States)

    Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

    2015-09-01

    The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

  2. Characterization of neonatal patients with intraventricular hemorrhage using 3D ultrasound cerebral ventricle volumes

    Science.gov (United States)

    Kishimoto, Jessica; Fenster, Aaron; Lee, David S. C.; de Ribaupierre, Sandrine

    2015-03-01

    One of the major non-congenital cause of neurological impairment among neonates born very preterm is intraventricular hemorrhage (IVH) - bleeding within the lateral ventricles. Most IVH patients will have a transient period of ventricle dilation that resolves spontaneously. However, those patients most at risk of long-term impairment are those who have progressive ventricle dilation as this causes macrocephaly, an abnormally enlarged head, then later causes increases intracranial pressure (ICP). 2D ultrasound (US) images through the fontanelles of the patients are serially acquired to monitor the progression of the ventricle dilation. These images are used to determine when interventional therapies such as needle aspiration of the built up CSF might be indicated for a patient. Initial therapies usually begin during the third week of life. Such interventions have been shown to decrease morbidity and mortality in IVH patients; however, this comes with risks of further hemorrhage or infection; therefore only patients requiring it should be treated. Previously we have developed and validated a 3D US system to monitor the progression of ventricle volumes (VV) in IVH patients. This system has been validated using phantoms and a small set of patient images. The aim of this work is to determine the ability of 3D US generated VV to categorize patients into those who will require interventional therapies, and those who will have spontaneous resolution. Patients with higher risks could therefore be monitored better, by re-allocating some of the resources as the low risks infants would need less monitoring.

  3. Fast and Easy 3D Reconstruction with the Help of Geometric Constraints and Genetic Algorithms

    Science.gov (United States)

    Annich, Afafe; El Abderrahmani, Abdellatif; Satori, Khalid

    2017-09-01

    The purpose of the work presented in this paper is to describe new method of 3D reconstruction from one or more uncalibrated images. This method is based on two important concepts: geometric constraints and genetic algorithms (GAs). At first, we are going to discuss the combination between bundle adjustment and GAs that we have proposed in order to improve 3D reconstruction efficiency and success. We used GAs in order to improve fitness quality of initial values that are used in the optimization problem. It will increase surely convergence rate. Extracted geometric constraints are used first to obtain an estimated value of focal length that helps us in the initialization step. Matching homologous points and constraints is used to estimate the 3D model. In fact, our new method gives us a lot of advantages: reducing the estimated parameter number in optimization step, decreasing used image number, winning time and stabilizing good quality of 3D results. At the end, without any prior information about our 3D scene, we obtain an accurate calibration of the cameras, and a realistic 3D model that strictly respects the geometric constraints defined before in an easy way. Various data and examples will be used to highlight the efficiency and competitiveness of our present approach.

  4. Birth weight and neonatal adiposity prediction using fractional limb volume obtained with 3D ultrasound.

    Science.gov (United States)

    O'Connor, Clare; O'Higgins, Amy; Doolan, Anne; Segurado, Ricardo; Stuart, Bernard; Turner, Michael J; Kennelly, Máireád M

    2014-01-01

    The objective of this investigation was to study fetal thigh volume throughout gestation and explore its correlation with birth weight and neonatal body composition. This novel technique may improve birth weight prediction and lead to improved detection rates for fetal growth restriction. Fractional thigh volume (TVol) using 3D ultrasound, fetal biometry and soft tissue thickness were studied longitudinally in 42 mother-infant pairs. The percentages of neonatal body fat, fat mass and fat-free mass were determined using air displacement plethysmography. Correlation and linear regression analyses were performed. Linear regression analysis showed an association between TVol and birth weight. TVol at 33 weeks was also associated with neonatal fat-free mass. There was no correlation between TVol and neonatal fat mass. Abdominal circumference, estimated fetal weight (EFW) and EFW centile showed consistent correlations with birth weight. Thigh volume demonstrated an additional independent contribution to birth weight prediction when added to the EFW centile from the 38-week scan (p = 0.03). Fractional TVol performed at 33 weeks gestation is correlated with birth weight and neonatal lean body mass. This screening test may highlight those at risk of fetal growth restriction or macrosomia.

  5. Tumor and normal structures volume localization and quantitation in 3D radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Anselmi, R.; Andreucci, L.

    1995-01-01

    Improvements in imaging technology have significantly enhanced the ability of the radiation oncologist to stage and to evaluate the response of tumor during and after treatment. Over the last few year, in fact, computed tomography (CT), magnetic resonance spectroscopy (MRS), positron emission tomography (PET), single photon emission computed tomography (SPECT) imaging radiolabelled monoclonal tumor antibodies have allowed tumor definition and evaluation. Concerning the above mentioned techniques accurate methods for the integration of morphological (CT, MRI) and functional (PET, SPECT, MRS) information can be very useful for volumes definition. In fact three-dimensional treatment planning depends heavily on volume displays and calculation based on volumes to convey information to the radiation oncologist, physicist and dosimetrist. The accuracy and reproducibility of the methods for creating these volumes are fundamental limitations of current treatment planning systems. Slice by slice manual contouring, which is extremely labor-intensive, and automatic edge detection, which has a high failure rate and requires human intervention are representative of the current standard of practice. The aim of our work is both to develop methods of image data integration and automatic segmentation, and to make the treatment planning system able to combine these multiple information in unified data set in order to get a better tumor volume definition and dose distribution calculation. Then the possibility of using morphological and functional images and other information coming from MR spectroscopy and electronic or confocal microscopy can allow the development into the treatment planning system of biological calculation models for evaluating tumor and normal tissue control probabilities (TCP, NTCP). The definitive use of these models into the 3-D treatment plannings will offer a considerable improvement in the biological efficacy of radiotherapy and it will constitute the object

  6. A critical evaluation of the planning target volume for 3-d conformal radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Tinger, Alfred; Michalski, Jeff M.; Cheng, Abel; Low, Daniel A.; Zhu, Ron; Bosch, Walter R.; Purdy, James A.; Perez, Carlos A.

    1996-01-01

    Purpose: The goal was to determine an adequate planning target volume (PTV) margin for three-dimensional conformal radiotherapy (3D CRT) of prostate cancer. The uncertainty in the internal positions of the prostate and seminal vesicles and the uncertainty in the treatment set-ups for a single group of patients was measured. Methods: Weekly computed tomography (CT) scans of the pelvis (n=38) and daily electronic portal images (n=1225) were reviewed for six patients who received seven-field 3D CRT for prostate cancer. The weekly CT scans were registered in three dimensions to the original treatment planning CT scan using commercially available software. This registration permitted measurement of the motion in the center-of-volume (COV) of the prostate and seminal vesicles throughout the course of therapy. The daily portal images (PI) were registered to the corresponding simulation films to measure the set-up displacement for each of the seven fields. The field displacements were then entered into a matrix program which calculated the isocenter displacement by a least squares method. The uncertainty in the internal positions of the prostate and seminal vesicles (standard deviation of the motions) was added to the uncertainty in the set-up (standard deviation of the isocenter displacements) in quadrature to arrive at a total uncertainty. Positive directions were defined in the left, anterior, and superior directions. A discussion of an adequate PTV was based on these results. Results: The mean magnitude of motion for the COV of the prostate ± the standard deviation was 0 ± 1 mm in the left-right (LR) direction, 0.5 ± 2.8 mm in the anterior-posterior (AP) direction, and 0.5 ± 3.5 mm in the superior-inferior (SI) direction. The mean magnitude of motion for the COV of the seminal vesicles ± the standard deviation was -0.3 ± 1.5 mm in the LR, 0.6 ± 4.1 mm in the AP, and 0.7 ± 2.3 mm in the SI directions, respectively. For all patients the mean isocenter

  7. NLT and extrapolated DLT:3-D cinematography alternatives for enlarging the volume of calibration.

    Science.gov (United States)

    Hinrichs, R N; McLean, S P

    1995-10-01

    This study investigated the accuracy of the direct linear transformation (DLT) and non-linear transformation (NLT) methods of 3-D cinematography/videography. A comparison of standard DLT, extrapolated DLT, and NLT calibrations showed the standard (non-extrapolated) DLT to be the most accurate, especially when a large number of control points (40-60) were used. The NLT was more accurate than the extrapolated DLT when the level of extrapolation exceeded 100%. The results indicated that when possible one should use the DLT with a control object, sufficiently large as to encompass the entire activity being studied. However, in situations where the activity volume exceeds the size of one's DLT control object, the NLT method should be considered.

  8. An open source workflow for 3D printouts of scientific data volumes

    Science.gov (United States)

    Loewe, P.; Klump, J. F.; Wickert, J.; Ludwig, M.; Frigeri, A.

    2013-12-01

    As the amount of scientific data continues to grow, researchers need new tools to help them visualize complex data. Immersive data-visualisations are helpful, yet fail to provide tactile feedback and sensory feedback on spatial orientation, as provided from tangible objects. The gap in sensory feedback from virtual objects leads to the development of tangible representations of geospatial information to solve real world problems. Examples are animated globes [1], interactive environments like tangible GIS [2], and on demand 3D prints. The production of a tangible representation of a scientific data set is one step in a line of scientific thinking, leading from the physical world into scientific reasoning and back: The process starts with a physical observation, or from a data stream generated by an environmental sensor. This data stream is turned into a geo-referenced data set. This data is turned into a volume representation which is converted into command sequences for the printing device, leading to the creation of a 3D printout. As a last, but crucial step, this new object has to be documented and linked to the associated metadata, and curated in long term repositories to preserve its scientific meaning and context. The workflow to produce tangible 3D data-prints from science data at the German Research Centre for Geosciences (GFZ) was implemented as a software based on the Free and Open Source Geoinformatics tools GRASS GIS and Paraview. The workflow was successfully validated in various application scenarios at GFZ using a RapMan printer to create 3D specimens of elevation models, geological underground models, ice penetrating radar soundings for planetology, and space time stacks for Tsunami model quality assessment. While these first pilot applications have demonstrated the feasibility of the overall approach [3], current research focuses on the provision of the workflow as Software as a Service (SAAS), thematic generalisation of information content and

  9. 3D mapping of cerebrospinal fluid local volume changes in patients with hydrocephalus treated by surgery: preliminary study

    International Nuclear Information System (INIS)

    Hodel, Jerome; Besson, Pierre; Pruvo, Jean-Pierre; Leclerc, Xavier; Rahmouni, Alain; Grandjacques, Benedicte; Luciani, Alain; Petit, Eric; Lebret, Alain; Outteryck, Olivier; Benadjaoud, Mohamed Amine; Maraval, Anne; Decq, Philippe

    2014-01-01

    To develop automated deformation modelling for the assessment of cerebrospinal fluid (CSF) local volume changes in patients with hydrocephalus treated by surgery. Ventricular and subarachnoid CSF volume changes were mapped by calculating the Jacobian determinant of the deformation fields obtained after non-linear registration of pre- and postoperative images. A total of 31 consecutive patients, 15 with communicating hydrocephalus (CH) and 16 with non-communicating hydrocephalus (NCH), were investigated before and after surgery using a 3D SPACE (sampling perfection with application optimised contrast using different flip-angle evolution) sequence. Two readers assessed CSF volume changes using 3D colour-encoded maps. The Evans index and postoperative volume changes of the lateral ventricles and sylvian fissures were quantified and statistically compared. Before surgery, sylvian fissure and brain ventricle volume differed significantly between CH and NCH (P = 0.001 and P = 0.025, respectively). After surgery, 3D colour-encoded maps allowed for the visual recognition of the CSF volume changes in all patients. The amounts of ventricle volume loss of CH and NCH patients were not significantly different (P = 0.30), whereas readjustment of the sylvian fissure volume was conflicting in CH and NCH patients (P < 0.001). The Evans index correlated with ventricle volume in NCH patients. 3D mapping of CSF volume changes is feasible providing a quantitative follow-up of patients with hydrocephalus. (orig.)

  10. 3D mapping of cerebrospinal fluid local volume changes in patients with hydrocephalus treated by surgery: preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Hodel, Jerome [Hopital Roger Salengro, Department of Neuroradiology, Lille (France); Hopital Roger Salengro, Service de Neuroradiologie, Lille (France); Besson, Pierre; Pruvo, Jean-Pierre; Leclerc, Xavier [Hopital Roger Salengro, Department of Neuroradiology, Lille (France); Rahmouni, Alain; Grandjacques, Benedicte; Luciani, Alain [Hopital Henri Mondor, Department of Radiology, Creteil (France); Petit, Eric; Lebret, Alain [Signals Images and Intelligent Systems Laboratory, Creteil (France); Outteryck, Olivier [Hopital Roger Salengro, Department of Neurology, Lille (France); Benadjaoud, Mohamed Amine [Radiation Epidemiology Team, CESP, Centre for Research in Epidemiology and Population Health U1018, Villejuif (France); Maraval, Anne [Hopital Henri Mondor, Department of Neuroradiology, Creteil (France); Decq, Philippe [Hopital Henri Mondor, Department of Neurosurgery, Creteil (France)

    2014-01-15

    To develop automated deformation modelling for the assessment of cerebrospinal fluid (CSF) local volume changes in patients with hydrocephalus treated by surgery. Ventricular and subarachnoid CSF volume changes were mapped by calculating the Jacobian determinant of the deformation fields obtained after non-linear registration of pre- and postoperative images. A total of 31 consecutive patients, 15 with communicating hydrocephalus (CH) and 16 with non-communicating hydrocephalus (NCH), were investigated before and after surgery using a 3D SPACE (sampling perfection with application optimised contrast using different flip-angle evolution) sequence. Two readers assessed CSF volume changes using 3D colour-encoded maps. The Evans index and postoperative volume changes of the lateral ventricles and sylvian fissures were quantified and statistically compared. Before surgery, sylvian fissure and brain ventricle volume differed significantly between CH and NCH (P = 0.001 and P = 0.025, respectively). After surgery, 3D colour-encoded maps allowed for the visual recognition of the CSF volume changes in all patients. The amounts of ventricle volume loss of CH and NCH patients were not significantly different (P = 0.30), whereas readjustment of the sylvian fissure volume was conflicting in CH and NCH patients (P < 0.001). The Evans index correlated with ventricle volume in NCH patients. 3D mapping of CSF volume changes is feasible providing a quantitative follow-up of patients with hydrocephalus. (orig.)

  11. A fast time-difference inverse solver for 3D EIT with application to lung imaging.

    Science.gov (United States)

    Javaherian, Ashkan; Soleimani, Manuchehr; Moeller, Knut

    2016-08-01

    A class of sparse optimization techniques that require solely matrix-vector products, rather than an explicit access to the forward matrix and its transpose, has been paid much attention in the recent decade for dealing with large-scale inverse problems. This study tailors application of the so-called Gradient Projection for Sparse Reconstruction (GPSR) to large-scale time-difference three-dimensional electrical impedance tomography (3D EIT). 3D EIT typically suffers from the need for a large number of voxels to cover the whole domain, so its application to real-time imaging, for example monitoring of lung function, remains scarce since the large number of degrees of freedom of the problem extremely increases storage space and reconstruction time. This study shows the great potential of the GPSR for large-size time-difference 3D EIT. Further studies are needed to improve its accuracy for imaging small-size anomalies.

  12. Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study.

    Science.gov (United States)

    Ebert, Lars C; Schweitzer, Wolf; Gascho, Dominic; Ruder, Thomas D; Flach, Patricia M; Thali, Michael J; Ampanozi, Garyfalia

    2017-02-01

    The 3D volume-rendering technique (VRT) is commonly used in forensic radiology. Its main function is to explain medical findings to state attorneys, judges, or police representatives. New visualization algorithms permit the generation of almost photorealistic volume renderings of CT datasets. The objective of this study is to present and compare a variety of radiologic findings to illustrate the differences between and the advantages and limitations of the current VRT and the physically based cinematic rendering technique (CRT). Seventy volunteers were shown VRT and CRT reconstructions of 10 different cases. They were asked to mark the findings on the images and rate them in terms of realism and understandability. A total of 48 of the 70 questionnaires were returned and included in the analysis. On the basis of most of the findings presented, CRT appears to be equal or superior to VRT with respect to the realism and understandability of the visualized findings. Overall, in terms of realism, the difference between the techniques was statistically significant (p 0.05). CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis, and therefore it should be used primarily as a tool to deliver visual information in the form of radiologic image reports. Using CRT for forensic visualization might have advantages over using VRT if conveying a high degree of visual realism is of importance. Most of the shortcomings of CRT have to do with the software being an early prototype.

  13. Comparative study between the Spin-echo and 3-D fast imaging techniques in the Knee evaluation with magnetic resonance

    International Nuclear Information System (INIS)

    Oleaga Zufiria, L.; Ibanez Zubiarrain, A.; Grande Icaran, J.; Vela Martin, A.C.; Cintora Leon, E.; Grau Garcia, M.; Grande Icaran, D.

    1993-01-01

    We have carried out a retrospective analysis of the results of magnetic resonance (MR) studies in 20 patients, comparing two different sequences. We compared a 2-D spin-echo (SE2D) sequence with a 3-D fast imaging with steady-state precession (FISP3D) sequence in the attempt to compare the reliability of each in the detection of knee injuries. Arthroscopy was employed as a control technique. Our study revealed no statistically significant difference between the two sequences, although the overall sensitivity for the detection of meniscal lesions was slightly greater with the FISP3D sequence; however, the reliability in the detection of ruptures of the posterior cruciate ligament is less with this sequence than with the SE2D sequence. Both sequences showed very low sensitivity in the detection of hyaline cartilage injuries. (Author) 14 refs

  14. Comparison of respiratory-triggered 3-D fast spin-echo and single-shot fast spin-echo radial slab MR cholangiopancreatography images in children

    Energy Technology Data Exchange (ETDEWEB)

    Chavhan, Govind B.; Almehdar, Abeer; Gupta, Sumeet [The Hospital for Sick Children and University of Toronto, Department of Diagnostic Imaging, Toronto (Canada); Moineddin, Rahim [University of Toronto, Department of Family and Community Medicine, Toronto (Canada); Babyn, Paul S. [Royal University Hospital, Department of Medical Imaging, Saskatoon (Canada)

    2013-09-15

    The two most commonly performed magnetic resonance cholangiopancreatography (MRCP) sequences, 3-D fast spin-echo (3-D FSE) and single-shot fast spin-echo radial slabs (radial slabs), have not been compared in children. The purpose of this study was to compare 3-D FSE and radial slabs MRCP sequences on a 3-T scanner to determine their ability to show various segments of pancreaticobiliary tree and presence of artifacts in children. We reviewed 79 consecutive MRCPs performed in 74 children on a 3-T scanner. We noted visibility of major ducts on 3-D FSE and radial slabs. We noted the order of branching of ducts in the right and left hepatic ducts and the degree of visibility of the pancreatic duct. Statistical analysis was performed using McNemar and signed rank tests. There was no significant difference in the visibility of major bile ducts and the order of branching in the right hepatic lobe between sequences. A higher order of branching in the left lobe was seen on radial slabs than 3-D FSE (mean order of branching 2.82 versus 2.27; P-value = 0.0002). The visibility of pancreatic duct was better on radial slabs as compared to 3-D FSE (mean value of 1.53 vs. 0.90; P-value < 0.0001). 3-D FSE sequence was artifact-free in 25/79 (31.6%) MRCP exams as compared to radial slabs, which were artifact-free in 18/79 (22.8%) MRCP exams (P-value = 0.0001). There is no significant difference in the visibility of major bile ducts between 3-D FSE and radial slab MRCP sequences at 3-T in children. However, radial slab MRCP shows a higher order of branching in the left hepatic lobe and superior visibility of the pancreatic duct than 3-D FSE. (orig.)

  15. Fast multifrequency focal beam analysis for 3D seismic acquisition geometry

    NARCIS (Netherlands)

    Wei, W.; Fu, L.; Blacquiere, G.

    2012-01-01

    A method for the efficient computation of multifrequency focal beams for 3D seismic acquisition geometry analysis has been developed. By computing them for all the frequency components of seismic data, single-frequency focal beams can be extended to multifrequency focal beams. However, this

  16. Sparsity-based fast CGH generation using layer-based approach for 3D point cloud model

    Science.gov (United States)

    Kim, Hak Gu; Jeong, Hyunwook; Ro, Yong Man

    2017-03-01

    Computer generated hologram (CGH) is becoming increasingly important for a 3-D display in various applications including virtual reality. In the CGH, holographic fringe patterns are generated by numerically calculating them on computer simulation systems. However, a heavy computational cost is required to calculate the complex amplitude on CGH plane for all points of 3D objects. This paper proposes a new fast CGH generation based on the sparsity of CGH for 3D point cloud model. The aim of the proposed method is to significantly reduce computational complexity while maintaining the quality of the holographic fringe patterns. To that end, we present a new layer-based approach for calculating the complex amplitude distribution on the CGH plane by using sparse FFT (sFFT). We observe the CGH of a layer of 3D objects is sparse so that dominant CGH is rapidly generated from a small set of signals by sFFT. Experimental results have shown that the proposed method is one order of magnitude faster than recently reported fast CGH generation.

  17. Fast CSF MRI for brain segmentation; Cross-validation by comparison with 3D T1-based brain segmentation methods

    NARCIS (Netherlands)

    van der Kleij, Lisa A; de Bresser, Jeroen; Hendrikse, Jeroen; Siero, Jeroen C W; Petersen, Esben T; De Vis, Jill B

    2018-01-01

    OBJECTIVE: In previous work we have developed a fast sequence that focusses on cerebrospinal fluid (CSF) based on the long T2 of CSF. By processing the data obtained with this CSF MRI sequence, brain parenchymal volume (BPV) and intracranial volume (ICV) can be automatically obtained. The aim of

  18. Fast globally optimal segmentation of 3D prostate MRI with axial symmetry prior.

    Science.gov (United States)

    Qiu, Wu; Yuan, Jing; Ukwatta, Eranga; Sun, Yue; Rajchl, Martin; Fenster, Aaron

    2013-01-01

    We propose a novel global optimization approach to segmenting a given 3D prostate T2w magnetic resonance (MR) image, which enforces the inherent axial symmetry of the prostate shape and simultaneously performs a sequence of 2D axial slice-wise segmentations with a global 3D coherence prior. We show that the proposed challenging combinatorial optimization problem can be solved globally and exactly by means of convex relaxation. With this regard, we introduce a novel coupled continuous max-flow model, which is dual to the studied convex relaxed optimization formulation and leads to an efficient multiplier augmented algorithm based on the modern convex optimization theory. Moreover, the new continuous max-flow based algorithm was implemented on GPUs to achieve a substantial improvement in computation. Experimental results using public and in-house datasets demonstrate great advantages of the proposed method in terms of both accuracy and efficiency.

  19. A cost-effective LED and photodetector based fast direct 3D diffuse optical imaging system

    Science.gov (United States)

    Saikia, Manob Jyoti; Manjappa, Rakesh; Kanhirodan, Rajan

    2017-07-01

    A cost-effective and high-speed 3D diffuse optical tomography system using high power LED light sources and silicon photodetectors has been designed and built, that can continuously scan and reconstruct spectroscopic images at a frame rate of 2 fps. The system is experimentally validated with tissue mimicking cylindrical resin phantom having light absorbing inhomogeneities of different size, shape and contrast, and at different locations.

  20. Progressive attenuation fields: Fast 2D-3D image registration without precomputation

    International Nuclear Information System (INIS)

    Rohlfing, Torsten; Russakoff, Daniel B.; Denzler, Joachim; Mori, Kensaku; Maurer, Calvin R. Jr.

    2005-01-01

    Computation of digitally reconstructed radiograph (DRR) images is the rate-limiting step in most current intensity-based algorithms for the registration of three-dimensional (3D) images to two-dimensional (2D) projection images. This paper introduces and evaluates the progressive attenuation field (PAF), which is a new method to speed up DRR computation. A PAF is closely related to an attenuation field (AF). A major difference is that a PAF is constructed on the fly as the registration proceeds; it does not require any precomputation time, nor does it make any prior assumptions of the patient pose or limit the permissible range of patient motion. A PAF effectively acts as a cache memory for projection values once they are computed, rather than as a lookup table for precomputed projections like standard AFs. We use a cylindrical attenuation field parametrization, which is better suited for many medical applications of 2D-3D registration than the usual two-plane parametrization. The computed attenuation values are stored in a hash table for time-efficient storage and access. Using clinical gold-standard spine image data sets from five patients, we demonstrate consistent speedups of intensity-based 2D-3D image registration using PAF DRRs by a factor of 10 over conventional ray casting DRRs with no decrease of registration accuracy or robustness

  1. Implementation of a fast running full core pin power reconstruction method in DYN3D

    International Nuclear Information System (INIS)

    Gomez-Torres, Armando Miguel; Sanchez-Espinoza, Victor Hugo; Kliem, Sören; Gommlich, Andre

    2014-01-01

    Highlights: • New pin power reconstruction (PPR) method for the nodal diffusion code DYN3D. • Flexible PPR method applicable to a single, a group or to all fuel assemblies (square, hex). • Combination of nodal with pin-wise solutions (non-conform geometry). • PPR capabilities shown for REA of a Minicore (REA) PWR whole core. - Abstract: This paper presents a substantial extension of the pin power reconstruction (PPR) method used in the reactor dynamics code DYN3D with the aim to better describe the heterogeneity within the fuel assembly during reactor simulations. The flexibility of the new implemented PPR permits the local spatial refinement of one fuel assembly, of a cluster of fuel assemblies, of a quarter or eight of a core or even of a whole core. The application of PPR in core regions of interest will pave the way for the coupling with sub-channel codes enabling the prediction of local safety parameters. One of the main advantages of considering regions and not only a hot fuel assembly (FA) is the fact that the cross flow within this region can be taken into account by the subchannel code. The implementation of the new PPR method has been tested analysing a rod ejection accident (REA) in a PWR minicore consisting of 3 × 3 FA. Finally, the new capabilities of DNY3D are demonstrated by the analysing a boron dilution transient in a PWR MOX core and the pin power of a VVER-1000 reactor at stationary conditions

  2. Implementation of a fast running full core pin power reconstruction method in DYN3D

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Torres, Armando Miguel [Instituto Nacional de Investigaciones Nucleares, Department of Nuclear Systems, Carretera Mexico – Toluca s/n, La Marquesa, 52750 Ocoyoacac (Mexico); Sanchez-Espinoza, Victor Hugo, E-mail: victor.sanchez@kit.edu [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology, Hermann-vom-Helmhotz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Kliem, Sören; Gommlich, Andre [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden (Germany)

    2014-07-01

    Highlights: • New pin power reconstruction (PPR) method for the nodal diffusion code DYN3D. • Flexible PPR method applicable to a single, a group or to all fuel assemblies (square, hex). • Combination of nodal with pin-wise solutions (non-conform geometry). • PPR capabilities shown for REA of a Minicore (REA) PWR whole core. - Abstract: This paper presents a substantial extension of the pin power reconstruction (PPR) method used in the reactor dynamics code DYN3D with the aim to better describe the heterogeneity within the fuel assembly during reactor simulations. The flexibility of the new implemented PPR permits the local spatial refinement of one fuel assembly, of a cluster of fuel assemblies, of a quarter or eight of a core or even of a whole core. The application of PPR in core regions of interest will pave the way for the coupling with sub-channel codes enabling the prediction of local safety parameters. One of the main advantages of considering regions and not only a hot fuel assembly (FA) is the fact that the cross flow within this region can be taken into account by the subchannel code. The implementation of the new PPR method has been tested analysing a rod ejection accident (REA) in a PWR minicore consisting of 3 × 3 FA. Finally, the new capabilities of DNY3D are demonstrated by the analysing a boron dilution transient in a PWR MOX core and the pin power of a VVER-1000 reactor at stationary conditions.

  3. Accurate B-spline-based 3-D interpolation scheme for digital volume correlation

    Science.gov (United States)

    Ren, Maodong; Liang, Jin; Wei, Bin

    2016-12-01

    An accurate and efficient 3-D interpolation scheme, based on sampling theorem and Fourier transform technique, is proposed to reduce the sub-voxel matching error caused by intensity interpolation bias in digital volume correlation. First, the influence factors of the interpolation bias are investigated theoretically using the transfer function of an interpolation filter (henceforth filter) in the Fourier domain. A law that the positional error of a filter can be expressed as a function of fractional position and wave number is found. Then, considering the above factors, an optimized B-spline-based recursive filter, combining B-spline transforms and least squares optimization method, is designed to virtually eliminate the interpolation bias in the process of sub-voxel matching. Besides, given each volumetric image containing different wave number ranges, a Gaussian weighting function is constructed to emphasize or suppress certain of wave number ranges based on the Fourier spectrum analysis. Finally, a novel software is developed and series of validation experiments were carried out to verify the proposed scheme. Experimental results show that the proposed scheme can reduce the interpolation bias to an acceptable level.

  4. 3D isotropic T2-weighted fast spin echo (VISTA) versus 2D T2-weighted fast spin echo in evaluation of the calcaneofibular ligament in the oblique coronal plane.

    Science.gov (United States)

    Park, H J; Lee, S Y; Choi, Y J; Hong, H P; Park, S J; Park, J H; Kim, E

    2017-02-01

    To investigate whether the image quality of three-dimensional (3D) volume isotropic fast spin echo acquisition (VISTA) magnetic resonance imaging (MRI) of the calcaneofibular ligament (CFL) view is comparable to that of 2D fast spin echo T2-weighted images (2D T2 FSE) for the evaluation of the CFL, and whether 3D VISTA can replace 2D T2 FSE for the evaluation of CFL injuries. This retrospective study included 76 patients who underwent ankle MRI with CFL views of both 2D T2 FSE MRI and 3D VISTA. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of both techniques were measured. The anatomical identification score and diagnostic performances were evaluated by two readers independently. The diagnostic performances of 3D VISTA and 2D T2 FSE were analysed by sensitivity, specificity, and accuracy for diagnosing CFL injury with reference standards of surgically or clinically confirmed diagnoses. Surgical correlation was performed in 29% of the patients, and clinical examination was used in those who did not have surgery (71%). The SNRs and CNRs of 3D VISTA were significantly higher than those of 2D T2 FSE. The anatomical identification scores on 3D VISTA were inferior to those on 2D T2 FSE, and the differences were statistically significant (pT2 FSE for the anatomical evaluation of CFL, 3D VISTA has a diagnostic performance comparable to that of 2D T2 FSE for the diagnosis of CFL injuries. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  5. AxiSEM3D: a new fast method for global wave propagation in 3-D Earth models with undulating discontinuities

    Science.gov (United States)

    Leng, K.; Nissen-Meyer, T.; van Driel, M.; Al-Attar, D.

    2016-12-01

    We present a new, computationally efficient numerical method to simulate global seismic wave propagation in realistic 3-D Earth models with laterally heterogeneous media and finite boundary perturbations. Our method is a hybrid of pseudo-spectral and spectral element methods (SEM). We characterize the azimuthal dependence of 3-D wavefields in terms of Fourier series, such that the 3-D equations of motion reduce to an algebraic system of coupled 2-D meridional equations, which can be solved by a 2-D spectral element method (based on www.axisem.info). Computational efficiency of our method stems from lateral smoothness of global Earth models (with respect to wavelength) as well as axial singularity of seismic point sources, which jointly confine the Fourier modes of wavefields to a few lower orders. All boundary perturbations that violate geometric spherical symmetry, including Earth's ellipticity, topography and bathymetry, undulations of internal discontinuities such as Moho and CMB, are uniformly considered by means of a Particle Relabeling Transformation.The MPI-based high performance C++ code AxiSEM3D, is now available for forward simulations upon 3-D Earth models with fluid outer core, ellipticity, and both mantle and crustal structures. We show novel benchmarks for global wave solutions in 3-D mantle structures between our method and an independent, fully discretized 3-D SEM with remarkable agreement. Performance comparisons are carried out on three state-of-the-art tomography models, with seismic period going down to 5s. It is shown that our method runs up to two orders of magnitude faster than the 3-D SEM for such settings, and such computational advantage scales favourably with seismic frequency. By examining wavefields passing through hypothetical Gaussian plumes of varying sharpness, we identify in model-wavelength space the limits where our method may lose its advantage.

  6. On the implementation of fast marching methods for 3D lattices

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas

    2001-01-01

    This technical report discusses Sethian's Fast Marching Method and its higher accuracy variant. Both methods may be used to compute the arrival times at the points of a discrete lattice of a front which is monotonously expanding. Applications of the method include arrival time computation and the...

  7. An efficient and accurate 3D displacements tracking strategy for digital volume correlation

    KAUST Repository

    Pan, Bing; Wang, Bo; Wu, Dafang; Lubineau, Gilles

    2014-01-01

    inverse compositional Gauss-Newton (3D IC-GN) algorithm is introduced to replace existing forward additive algorithms for accurate sub-voxel displacement registration. Second, to ensure the 3D IC-GN algorithm that converges accurately and rapidly and avoid

  8. Calculated Specific Volumes and Magnetic Moments of the 3d Transition Metal Monoxides

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Andersen, O. K.; Johansson, B.

    1980-01-01

    We have performed self-consistent, spin-polarized band structure calculations as a function of the lattice spacing for the 3d metal monoxides in order to obtain the equilibrium lattice constants. The calculated binding from the 3d electrons and the occurrence of antiferromagnetism account...

  9. Very fast road database verification using textured 3D city models obtained from airborne imagery

    Science.gov (United States)

    Bulatov, Dimitri; Ziems, Marcel; Rottensteiner, Franz; Pohl, Melanie

    2014-10-01

    Road databases are known to be an important part of any geodata infrastructure, e.g. as the basis for urban planning or emergency services. Updating road databases for crisis events must be performed quickly and with the highest possible degree of automation. We present a semi-automatic algorithm for road verification using textured 3D city models, starting from aerial or even UAV-images. This algorithm contains two processes, which exchange input and output, but basically run independently from each other. These processes are textured urban terrain reconstruction and road verification. The first process contains a dense photogrammetric reconstruction of 3D geometry of the scene using depth maps. The second process is our core procedure, since it contains various methods for road verification. Each method represents a unique road model and a specific strategy, and thus is able to deal with a specific type of roads. Each method is designed to provide two probability distributions, where the first describes the state of a road object (correct, incorrect), and the second describes the state of its underlying road model (applicable, not applicable). Based on the Dempster-Shafer Theory, both distributions are mapped to a single distribution that refers to three states: correct, incorrect, and unknown. With respect to the interaction of both processes, the normalized elevation map and the digital orthophoto generated during 3D reconstruction are the necessary input - together with initial road database entries - for the road verification process. If the entries of the database are too obsolete or not available at all, sensor data evaluation enables classification of the road pixels of the elevation map followed by road map extraction by means of vectorization and filtering of the geometrically and topologically inconsistent objects. Depending on the time issue and availability of a geo-database for buildings, the urban terrain reconstruction procedure has semantic models

  10. [3D FSPGR (fast spoiled gradient echo) magnetic resonance imaging in the diagnosis of focal cortical dysplasia in children].

    Science.gov (United States)

    Alikhanov, A A; Sinitsyn, V E; Perepelova, E M; Mukhin, K Iu; Demushkina, A A; Omarova, M O; Piliia, S V

    2001-01-01

    Small dysplastic lesions of the cerebral cortex are often missed by conventional MRI methods. The identification of subtle structural abnormalities by traditional multiplanar rectilinear slices is often limited by the complex convolutional pattern of the brain. We used a method of FSPGR (fast spoiled gradient-echo) of three-dimensional MRI data that improves the anatomical display of the sulcal structure of the hemispheric convexities. It also reduces the asymmetric sampling of gray-white matter that may lead to false-positive results. We present 5 from 12 patients with dysplastic cortical lesions in whom conventional two-dimensional and three-dimensional MRI with multiplanar reformatting was initially considered normal. Subsequent studies using 3D FSPGR identified various types of focal cortical dysplasia in all. These results indicate that an increase in the detection of subtle focal dysplastic lesions may be accomplished when one improves the anatomical display of the brain sulcal structure by performing 3D FSPGR.

  11. 3D wake measurements from a scanning wind lidar in combination with a fast wind field reconstruction model

    DEFF Research Database (Denmark)

    Mikkelsen, Torben Krogh; Herges, T. G.; Astrup, Poul

    2017-01-01

    University of Denmark. The purpose of the SpinnerLidar measurements at SWIFT is to measure the response of a V27 turbine wake to varying inflow conditions and turbine operating states. Although our fast scanning SpinnerLidar is able to measure the line-of-sight projected wind speed at up to 400 points per......-Stokes CFD code “Lincom Cyclop-buster model,”3 the corresponding 3D wind vector field (u, v, w) can be reconstructed under constraints for conservation of mass and momentum. The resulting model calculated line-of-sight projections of the 3D wind velocity vectors will become consistent with the line...

  12. 3D Dynamic Modeling of the Head-Neck Complex for Fast Eye and Head Orientation Movements Research

    Directory of Open Access Journals (Sweden)

    Daniel A. Sierra

    2011-01-01

    Full Text Available A 3D dynamic computer model for the movement of the head-neck complex is presented. It incorporates anatomically correct information about the diverse elements forming the system. The skeleton is considered as a set of interconnected rigid 3D bodies following the Newton-Euler laws of movement. The muscles are modeled using Enderle's linear model, which shows equivalent dynamic characteristics to Loeb's virtual muscle model. The soft tissues, namely, the ligaments, intervertebral disks, and facet joints, are modeled considering their physiological roles and dynamics. In contrast with other head and neck models developed for safety research, the model is aimed to study the neural control of the complex during fast eye and head movements, such as saccades and gaze shifts. In particular, the time-optimal hypothesis and the feedback control ones are discussed.

  13. Evaluation of right ventricular function by coronary computed tomography angiography using a novel automated 3D right ventricle volume segmentation approach: a validation study.

    Science.gov (United States)

    Burghard, Philipp; Plank, Fabian; Beyer, Christoph; Müller, Silvana; Dörler, Jakob; Zaruba, Marc-Michael; Pölzl, Leo; Pölzl, Gerhard; Klauser, Andrea; Rauch, Stefan; Barbieri, Fabian; Langer, Christian-Ekkehardt; Schgoer, Wilfried; Williamson, Eric E; Feuchtner, Gudrun

    2018-06-04

    To evaluate right ventricle (RV) function by coronary computed tomography angiography (CTA) using a novel automated three-dimensional (3D) RV volume segmentation tool in comparison with clinical reference modalities. Twenty-six patients with severe end-stage heart failure [left ventricle (LV) ejection fraction (EF) right heart invasive catheterisation (IC). Automated 3D RV volume segmentation was successful in 26 (100%) patients. Read-out time was 3 min 33 s (range, 1 min 50s-4 min 33s). RV EF by CTA was stronger correlated with right atrial pressure (RAP) by IC (r = -0.595; p = 0.006) but weaker with TAPSE (r = 0.366, p = 0.94). When comparing TAPSE with RAP by IC (r = -0.317, p = 0.231), a weak-to-moderate non-significant inverse correlation was found. Interobserver correlation was high with r = 0.96 (p right atrium (RA) and right ventricle (RV) was 196.9 ± 75.3 and 217.5 ± 76.1 HU, respectively. Measurement of RV function by CTA using a novel 3D volumetric segmentation tool is fast and reliable by applying a dedicated biphasic injection protocol. The RV EF from CTA is a closer surrogate of RAP than TAPSE by TTE. • Evaluation of RV function by cardiac CTA by using a novel 3D volume segmentation tool is fast and reliable. • A biphasic contrast agent injection protocol ensures homogenous RV contrast attenuation. • Cardiac CT is a valuable alternative modality to CMR for the evaluation of RV function.

  14. Using high-order polynomial basis in 3-D EM forward modeling based on volume integral equation method

    Science.gov (United States)

    Kruglyakov, Mikhail; Kuvshinov, Alexey

    2018-05-01

    3-D interpretation of electromagnetic (EM) data of different origin and scale becomes a common practice worldwide. However, 3-D EM numerical simulations (modeling)—a key part of any 3-D EM data analysis—with realistic levels of complexity, accuracy and spatial detail still remains challenging from the computational point of view. We present a novel, efficient 3-D numerical solver based on a volume integral equation (IE) method. The efficiency is achieved by using a high-order polynomial (HOP) basis instead of the zero-order (piecewise constant) basis that is invoked in all routinely used IE-based solvers. We demonstrate that usage of the HOP basis allows us to decrease substantially the number of unknowns (preserving the same accuracy), with corresponding speed increase and memory saving.

  15. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc, E-mail: Luc.Beaulieu@phy.ulaval.ca [Département de physique, de génie physique et d’optique et Centre de recherche sur le cancer de l’Université Laval, Université Laval, Québec, Québec G1V 0A6, Canada and Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec, 11 Côte du Palais, Québec, Québec G1R 2J6 (Canada); Binnekamp, Dirk [Integrated Clinical Solutions and Marketing, Philips Healthcare, Veenpluis 4-6, Best 5680 DA (Netherlands)

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  16. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    International Nuclear Information System (INIS)

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-01-01

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora ® Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators

  17. Fast 3D seismic wave simulations of 24 August 2016 Mw 6.0 central Italy earthquake for visual communication

    Directory of Open Access Journals (Sweden)

    Emanuele Casarotti

    2016-12-01

    Full Text Available We present here the first application of the fast reacting framework for 3D simulations of seismic wave propagation generated by earthquakes in the Italian region with magnitude Mw 5. The driven motivation is to offer a visualization of the natural phenomenon to the general public but also to provide preliminary modeling to expert and civil protection operators. We report here a description of this framework during the emergency of 24 August 2016 Mw 6.0 central Italy Earthquake, a discussion on the accuracy of the simulation for this seismic event and a preliminary critical analysis of the visualization structure and of the reaction of the public.

  18. Fast 3D elastic micro-seismic source location using new GPU features

    Science.gov (United States)

    Xue, Qingfeng; Wang, Yibo; Chang, Xu

    2016-12-01

    In this paper, we describe new GPU features and their applications in passive seismic - micro-seismic location. Locating micro-seismic events is quite important in seismic exploration, especially when searching for unconventional oil and gas resources. Different from the traditional ray-based methods, the wave equation method, such as the method we use in our paper, has a remarkable advantage in adapting to low signal-to-noise ratio conditions and does not need a person to select the data. However, because it has a conspicuous deficiency due to its computation cost, these methods are not widely used in industrial fields. To make the method useful, we implement imaging-like wave equation micro-seismic location in a 3D elastic media and use GPU to accelerate our algorithm. We also introduce some new GPU features into the implementation to solve the data transfer and GPU utilization problems. Numerical and field data experiments show that our method can achieve a more than 30% performance improvement in GPU implementation just by using these new features.

  19. Comparing an accelerated 3D fast spin-echo sequence (CS-SPACE) for knee 3-T magnetic resonance imaging with traditional 3D fast spin-echo (SPACE) and routine 2D sequences

    Energy Technology Data Exchange (ETDEWEB)

    Altahawi, Faysal F.; Blount, Kevin J.; Omar, Imran M. [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Morley, Nicholas P. [Marshfield Clinic, Department of Radiology, Marshfield, WI (United States); Raithel, Esther [Siemens Healthcare GmbH, Erlangen (Germany)

    2017-01-15

    To compare a faster, new, high-resolution accelerated 3D-fast-spin-echo (3D-FSE) acquisition sequence (CS-SPACE) to traditional 2D and high-resolution 3D sequences for knee 3-T magnetic resonance imaging (MRI). Twenty patients received knee MRIs that included routine 2D (T1, PD ± FS, T2-FS; 0.5 x 0.5 x 3 mm{sup 3}; ∝10 min), traditional 3D FSE (SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝7.5 min), and accelerated 3D-FSE prototype (CS-SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝5 min) acquisitions on a 3-T MRI system (Siemens MAGNETOM Skyra). Three musculoskeletal radiologists (MSKRs) prospectively and independently reviewed the studies with graded surveys comparing image and diagnostic quality. Tissue-specific signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were also compared. MSKR-perceived diagnostic quality of cartilage was significantly higher for CS-SPACE than for SPACE and 2D sequences (p < 0.001). Assessment of diagnostic quality of menisci and synovial fluid was higher for CS-SPACE than for SPACE (p < 0.001). CS-SPACE was not significantly different from SPACE but had lower assessments than 2D sequences for evaluation of bones, ligaments, muscles, and fat (p ≤ 0.004). 3D sequences had higher spatial resolution, but lower overall assessed contrast (p < 0.001). Overall image quality from CS-SPACE was assessed as higher than SPACE (p = 0.007), but lower than 2D sequences (p < 0.001). Compared to SPACE, CS-SPACE had higher fluid SNR and CNR against all other tissues (all p < 0.001). The CS-SPACE prototype allows for faster isotropic acquisitions of knee MRIs over currently used protocols. High fluid-to-cartilage CNR and higher spatial resolution over routine 2D sequences may present a valuable role for CS-SPACE in the evaluation of cartilage and menisci. (orig.)

  20. Intra- and interobserver variability of thyroid volume measurements in healthy adults by 2D versus 3D ultrasound

    International Nuclear Information System (INIS)

    Andermann, P.; Schloegl, S.; Maeder, U.; Luster, M.; Lassmann, M.; Reiners, C.

    2007-01-01

    Thyroid volume measurement by ultrasonography (US) is essential in numerous clinical diagnostic and therapeutic fields. While known to be limited, the accuracy and precision of two-dimensional (2D) US thyroid volume measurement have not been thoroughly characterized. Objective: We sought to assess the intra- and interobserver variability, accuracy and precision of thyroid volume determination by conventional 2D US in healthy adults using reference volumes determined by three-dimensional (3D) US. Design, methods: In a prospective blinded trial, thyroid volumes of ten volunteers were determined repeatedly by nine experienced sonographers using conventional 2D US (ellipsoid model). The values obtained were statistically compared to the so-called true volumes determined by 3D US (multiplanar approximation), the so-called gold standard, to estimate systematic errors and relative deviations of individual observers. Results: The standard error of measurement (SEM) for one observer and successive measurements (intraobserver variability), was 14%, and for different observers and repeated measurements (interobserver variability), 17%. The minimum relative thyroid volume change significantly different at the 95% level was 39% for the same observer and 46% for different observers. Regarding accuracy, the mean value of the differences showed a significant thyroid volume overestimation (17%, p <0.01) by 2D relative to 3D US. Conclusion: 2D US is appropriate for routine thyroid volumetry. Nevertheless, the so-called human factor (random error) should be kept in mind and correction is needed for methodical bias (systematic error). Further efforts are required to improve the accuracy and precision of 2D US thyroid volumetry by optimizing the underlying geometrical modeling or by the application of 3D US. (orig.)

  1. 3D hybrid profile order technique in a single breath-hold 3D T2-weighted fast spin-echo sequence: Usefulness in diagnosis of small liver lesions.

    Science.gov (United States)

    Hirata, Kenichiro; Nakaura, Takeshi; Okuaki, Tomoyuki; Tsuda, Noriko; Taguchi, Narumi; Oda, Seitaro; Utsunomiya, Daisuke; Yamashita, Yasuyuki

    2018-01-01

    We compared the efficacy of three-dimensional (3D) isotropic T2-weighted fast spin-echo imaging using a 3D hybrid profile order technique with a single-breath-hold (3D-Hybrid BH) with a two-dimensional (2D) T2-weighted fast spin-echo conventional respiratory-gated (2D-Conventional RG) technique for visualising small liver lesions. This study was approved by our institutional review board. The requirement to obtain written informed consent was waived. Fifty patients with small (≤15mm) hepatocellular carcinomas (HCC) (n=26), or benign cysts (n=24), had undergone hepatic MRI including both 2D-Conventional RG and 3D-Hybrid BH. We calculated the signal-to-noise ratio (SNR) and tumour-to-liver contrast (TLC). The diagnostic performance of the two protocols was analysed. The image acquisition time was 89% shorter with the 3D-Hybrid BH than with 2D-Conventional RG. There was no significant difference in the SNR between the two protocols. The area under the curve (AUC) of the TLC was significantly higher on 3D-Hybrid BH than on 2D-Conventional RG. The 3D-Hybrid BH sequence significantly improved diagnostic performance for small liver lesions with a shorter image acquisition time without sacrificing accuracy. Copyright © 2017. Published by Elsevier B.V.

  2. On the utility of 3D hand cursors to explore medical volume datasets with a touchless interface.

    Science.gov (United States)

    Lopes, Daniel Simões; Parreira, Pedro Duarte de Figueiredo; Paulo, Soraia Figueiredo; Nunes, Vitor; Rego, Paulo Amaral; Neves, Manuel Cassiano; Rodrigues, Pedro Silva; Jorge, Joaquim Armando

    2017-08-01

    Analyzing medical volume datasets requires interactive visualization so that users can extract anatomo-physiological information in real-time. Conventional volume rendering systems rely on 2D input devices, such as mice and keyboards, which are known to hamper 3D analysis as users often struggle to obtain the desired orientation that is only achieved after several attempts. In this paper, we address which 3D analysis tools are better performed with 3D hand cursors operating on a touchless interface comparatively to a 2D input devices running on a conventional WIMP interface. The main goals of this paper are to explore the capabilities of (simple) hand gestures to facilitate sterile manipulation of 3D medical data on a touchless interface, without resorting on wearables, and to evaluate the surgical feasibility of the proposed interface next to senior surgeons (N=5) and interns (N=2). To this end, we developed a touchless interface controlled via hand gestures and body postures to rapidly rotate and position medical volume images in three-dimensions, where each hand acts as an interactive 3D cursor. User studies were conducted with laypeople, while informal evaluation sessions were carried with senior surgeons, radiologists and professional biomedical engineers. Results demonstrate its usability as the proposed touchless interface improves spatial awareness and a more fluent interaction with the 3D volume than with traditional 2D input devices, as it requires lesser number of attempts to achieve the desired orientation by avoiding the composition of several cumulative rotations, which is typically necessary in WIMP interfaces. However, tasks requiring precision such as clipping plane visualization and tagging are best performed with mouse-based systems due to noise, incorrect gestures detection and problems in skeleton tracking that need to be addressed before tests in real medical environments might be performed. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Prosthetic component segmentation with blur compensation: a fast method for 3D fluoroscopy.

    Science.gov (United States)

    Tarroni, Giacomo; Tersi, Luca; Corsi, Cristiana; Stagni, Rita

    2012-06-01

    A new method for prosthetic component segmentation from fluoroscopic images is presented. The hybrid approach we propose combines diffusion filtering, region growing and level-set techniques without exploiting any a priori knowledge of the analyzed geometry. The method was evaluated on a synthetic dataset including 270 images of knee and hip prosthesis merged to real fluoroscopic data simulating different conditions of blurring and illumination gradient. The performance of the method was assessed by comparing estimated contours to references using different metrics. Results showed that the segmentation procedure is fast, accurate, independent on the operator as well as on the specific geometrical characteristics of the prosthetic component, and able to compensate for amount of blurring and illumination gradient. Importantly, the method allows a strong reduction of required user interaction time when compared to traditional segmentation techniques. Its effectiveness and robustness in different image conditions, together with simplicity and fast implementation, make this prosthetic component segmentation procedure promising and suitable for multiple clinical applications including assessment of in vivo joint kinematics in a variety of cases.

  4. A simple method for the production of large volume 3D macroporous hydrogels for advanced biotechnological, medical and environmental applications

    Science.gov (United States)

    Savina, Irina N.; Ingavle, Ganesh C.; Cundy, Andrew B.; Mikhalovsky, Sergey V.

    2016-02-01

    The development of bulk, three-dimensional (3D), macroporous polymers with high permeability, large surface area and large volume is highly desirable for a range of applications in the biomedical, biotechnological and environmental areas. The experimental techniques currently used are limited to the production of small size and volume cryogel material. In this work we propose a novel, versatile, simple and reproducible method for the synthesis of large volume porous polymer hydrogels by cryogelation. By controlling the freezing process of the reagent/polymer solution, large-scale 3D macroporous gels with wide interconnected pores (up to 200 μm in diameter) and large accessible surface area have been synthesized. For the first time, macroporous gels (of up to 400 ml bulk volume) with controlled porous structure were manufactured, with potential for scale up to much larger gel dimensions. This method can be used for production of novel 3D multi-component macroporous composite materials with a uniform distribution of embedded particles. The proposed method provides better control of freezing conditions and thus overcomes existing drawbacks limiting production of large gel-based devices and matrices. The proposed method could serve as a new design concept for functional 3D macroporous gels and composites preparation for biomedical, biotechnological and environmental applications.

  5. AUTOJOM, Quadratic Equation Coefficient for Conic Volume, Parallelepipeds, Wedges, Pyramids. JOMREAD, Check of 3-D Geometry Structure from Quadratic Surfaces

    International Nuclear Information System (INIS)

    2005-01-01

    Nature of physical problem solved: AUTOJOM is a computer program that will generate the coefficients of any quadratic equation used to define conic volumes and also the coefficients of the planes needed to define parallelepipeds, wedges, and pyramids. JOMREAD is a computer code to check any 3D geometry composed of and constructed with quadratic surfaces

  6. Fast multiview three-dimensional reconstruction method using cost volume filtering

    Science.gov (United States)

    Lee, Seung Joo; Park, Min Ki; Jang, In Yeop; Lee, Kwan H.

    2014-03-01

    As the number of customers who want to record three-dimensional (3-D) information using a mobile electronic device increases, it becomes more and more important to develop a method which quickly reconstructs a 3-D model from multiview images. A fast multiview-based 3-D reconstruction method is presented, which is suitable for the mobile environment by constructing a cost volume of the 3-D height field. This method consists of two steps: the construction of a reliable base surface and the recovery of shape details. In each step, the cost volume is constructed using photoconsistency and then it is filtered according to the multiscale. The multiscale-based cost volume filtering allows the 3-D reconstruction to maintain the overall shape and to preserve the shape details. We demonstrate the strength of the proposed method in terms of computation time, accuracy, and unconstrained acquisition environment.

  7. NCC-RANSAC: a fast plane extraction method for 3-D range data segmentation.

    Science.gov (United States)

    Qian, Xiangfei; Ye, Cang

    2014-12-01

    This paper presents a new plane extraction (PE) method based on the random sample consensus (RANSAC) approach. The generic RANSAC-based PE algorithm may over-extract a plane, and it may fail in case of a multistep scene where the RANSAC procedure results in multiple inlier patches that form a slant plane straddling the steps. The CC-RANSAC PE algorithm successfully overcomes the latter limitation if the inlier patches are separate. However, it fails if the inlier patches are connected. A typical scenario is a stairway with a stair wall where the RANSAC plane-fitting procedure results in inliers patches in the tread, riser, and stair wall planes. They connect together and form a plane. The proposed method, called normal-coherence CC-RANSAC (NCC-RANSAC), performs a normal coherence check to all data points of the inlier patches and removes the data points whose normal directions are contradictory to that of the fitted plane. This process results in separate inlier patches, each of which is treated as a candidate plane. A recursive plane clustering process is then executed to grow each of the candidate planes until all planes are extracted in their entireties. The RANSAC plane-fitting and the recursive plane clustering processes are repeated until no more planes are found. A probabilistic model is introduced to predict the success probability of the NCC-RANSAC algorithm and validated with real data of a 3-D time-of-flight camera-SwissRanger SR4000. Experimental results demonstrate that the proposed method extracts more accurate planes with less computational time than the existing RANSAC-based methods.

  8. Suppression law of quantum states in a 3D photonic fast Fourier transform chip

    Science.gov (United States)

    Crespi, Andrea; Osellame, Roberto; Ramponi, Roberta; Bentivegna, Marco; Flamini, Fulvio; Spagnolo, Nicolò; Viggianiello, Niko; Innocenti, Luca; Mataloni, Paolo; Sciarrino, Fabio

    2016-01-01

    The identification of phenomena able to pinpoint quantum interference is attracting large interest. Indeed, a generalization of the Hong–Ou–Mandel effect valid for any number of photons and optical modes would represent an important leap ahead both from a fundamental perspective and for practical applications, such as certification of photonic quantum devices, whose computational speedup is expected to depend critically on multi-particle interference. Quantum distinctive features have been predicted for many particles injected into multimode interferometers implementing the Fourier transform over the optical modes. Here we develop a scalable approach for the implementation of the fast Fourier transform algorithm using three-dimensional photonic integrated interferometers, fabricated via femtosecond laser writing technique. We observe the suppression law for a large number of output states with four- and eight-mode optical circuits: the experimental results demonstrate genuine quantum interference between the injected photons, thus offering a powerful tool for diagnostic of photonic platforms. PMID:26843135

  9. Fast spatial beam shaping by acousto-optic diffraction for 3D non-linear microscopy.

    Science.gov (United States)

    Akemann, Walther; Léger, Jean-François; Ventalon, Cathie; Mathieu, Benjamin; Dieudonné, Stéphane; Bourdieu, Laurent

    2015-11-02

    Acousto-optic deflection (AOD) devices offer unprecedented fast control of the entire spatial structure of light beams, most notably their phase. AOD light modulation of ultra-short laser pulses, however, is not straightforward to implement because of intrinsic chromatic dispersion and non-stationarity of acousto-optic diffraction. While schemes exist to compensate chromatic dispersion, non-stationarity remains an obstacle. In this work we demonstrate an efficient AOD light modulator for stable phase modulation using time-locked generation of frequency-modulated acoustic waves at the full repetition rate of a high power laser pulse amplifier of 80 kHz. We establish the non-local relationship between the optical phase and the generating acoustic frequency function and verify the system for temporal stability, phase accuracy and generation of non-linear two-dimensional phase functions.

  10. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation

    International Nuclear Information System (INIS)

    Sakhalkar, H. S.; Oldham, M.

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of ∼5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 μm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the 'gold standard' technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few millimeters of the

  11. Fast particles identification in programmable form at level-0 trigger by means of the 3D-Flow system

    International Nuclear Information System (INIS)

    Crosetto, Dario B.

    1998-01-01

    The 3D-Flow Processor system is a new, technology-independent concept in very fast, real-time system architectures. Based on either an FPGA or an ASIC implementation, it can address, in a fully programmable manner, applications where commercially available processors would fail because of throughput requirements. Possible applications include filtering-algorithms (pattern recognition) from the input of multiple sensors, as well as moving any input validated by these filtering-algorithms to a single output channel. Both operations can easily be implemented on a 3D-Flow system to achieve a real-time processing system with a very short lag time. This system can be built either with off-the-shelf FPGAs or, for higher data rates, with CMOS chips containing 4 to 16 processors each. The basic building block of the system, a 3D-Flow processor, has been successfully designed in VHDL code written in ''Generic HDL'' (mostly made of reusable blocks that are synthesizable in different technologies, or FPGAs), to produce a netlist for a four-processor ASIC featuring 0.35 micron CBA (Ceil Base Array) technology at 3.3 Volts, 884 mW power dissipation at 60 MHz and 63.75 mm sq. die size. The same VHDL code has been targeted to three FPGA manufacturers (Altera EPF10K250A, ORCA-Lucent Technologies 0R3T165 and Xilinx XCV1000). A complete set of software tools, the 3D-Flow System Manager, equally applicable to ASIC or FPGA implementations, has been produced to provide full system simulation, application development, real-time monitoring, and run-time fault recovery. Today's technology can accommodate 16 processors per chip in a medium size die, at a cost per processor of less than $5 based on the current silicon die/size technology cost

  12. Fast, free-breathing, in vivo fetal imaging using time-resolved 3D MRI technique: preliminary results.

    Science.gov (United States)

    Liu, Jing; Glenn, Orit A; Xu, Duan

    2014-04-01

    Fetal MR imaging is very challenging due to the movement of fetus and the breathing motion of the mother. Current clinical protocols involve quick 2D scouting scans to determine scan plane and often several attempts to reorient the scan plane when the fetus moves. This makes acquisition of fetal MR images clinically challenging and results in long scan times in order to obtain images that are of diagnostic quality. Compared to 2D imaging, 3D imaging of the fetus has many advantages such as higher SNR and ability to reformat images in multiple planes. However, it is more sensitive to motion and challenging for fetal imaging due to irregular fetal motion in addition to maternal breathing and cardiac motion. This aim of this study is to develop a fast 3D fetal imaging technique to resolve the challenge of imaging the moving fetus. This 3D imaging sequence has multi-echo radial sampling in-plane and conventional Cartesian encoding through plane, which provides motion robustness and high data acquisition efficiency. The utilization of a golden-ratio based projection profile allows flexible time-resolved image reconstruction with arbitrary temporal resolution at arbitrary time points as well as high signal-to-noise and contrast-to-noise ratio. The nice features of the developed image technique allow the 3D visualization of the movements occurring throughout the scan. In this study, we applied this technique to three human subjects for fetal MRI and achieved promising preliminary results of fetal brain, heart and lung imaging.

  13. A low volume 3D-printed temperature-controllable cuvette for UV visible spectroscopy.

    Science.gov (United States)

    Pisaruka, Jelena; Dymond, Marcus K

    2016-10-01

    We report the fabrication of a 3D-printed water-heated cuvette that fits into a standard UV visible spectrophotometer. Full 3D-printable designs are provided and 3D-printing conditions have been optimised to provide options to print the cuvette in either acrylonitrile butadiene styrene or polylactic acid polymers, extending the range of solvents that are compatible with the design. We demonstrate the efficacy of the cuvette by determining the critical micelle concentration of sodium dodecyl sulphate at 40 °C, the molar extinction coefficients of cobalt nitrate and dsDNA and by reproducing the thermochromic UV visible spectrum of a mixture of cobalt chloride, water and propan-2-ol. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. 3D laser scanning in civil engineering - measurements of volume of earth masses

    Science.gov (United States)

    Pawłowicz, J. A.; Szafranko, E.; Harasymiuk, J.

    2018-03-01

    Considering the constant drive to improve and accelerate building processes as well as possible applications of the latest technological achievements in civil engineering practice, the author has proposed to use 3D laser scanning in the construction industry. For example, data achieved through a 3D laser scanning process will facilitate making inventories of parameters of buildings in a very short time, will enable one to check irregularly shaped masses of earth, heavy and practically impossible to calculate precisely using traditional techniques. The other part of the research, performed in the laboratory, consisted of measurements of a model mound of earth. All the measurements were made with a 3D SkanStation C10 laser scanner manufactured by Leica. The data were analyzed. The results suggest that there are great opportunities for using the laser scanning technology in civil engineering

  15. LBM-EP: Lattice-Boltzmann method for fast cardiac electrophysiology simulation from 3D images.

    Science.gov (United States)

    Rapaka, S; Mansi, T; Georgescu, B; Pop, M; Wright, G A; Kamen, A; Comaniciu, Dorin

    2012-01-01

    Current treatments of heart rhythm troubles require careful planning and guidance for optimal outcomes. Computational models of cardiac electrophysiology are being proposed for therapy planning but current approaches are either too simplified or too computationally intensive for patient-specific simulations in clinical practice. This paper presents a novel approach, LBM-EP, to solve any type of mono-domain cardiac electrophysiology models at near real-time that is especially tailored for patient-specific simulations. The domain is discretized on a Cartesian grid with a level-set representation of patient's heart geometry, previously estimated from images automatically. The cell model is calculated node-wise, while the transmembrane potential is diffused using Lattice-Boltzmann method within the domain defined by the level-set. Experiments on synthetic cases, on a data set from CESC'10 and on one patient with myocardium scar showed that LBM-EP provides results comparable to an FEM implementation, while being 10 - 45 times faster. Fast, accurate, scalable and requiring no specific meshing, LBM-EP paves the way to efficient and detailed models of cardiac electrophysiology for therapy planning.

  16. 3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

    International Nuclear Information System (INIS)

    Hornblower, V D M; Yu, E; Fenster, A; Battista, J J; Malthaner, R A

    2007-01-01

    The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial 'tumours' were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the 'tumours' were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure 'tumour' volumes both in vivo and ex vivo

  17. 3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

    Energy Technology Data Exchange (ETDEWEB)

    Hornblower, V D M [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Yu, E [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Fenster, A [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Battista, J J [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada); Malthaner, R A [Canadian Surgical Technologies and Advanced Robotics, London, Ontario (Canada)

    2007-01-07

    The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial 'tumours' were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the 'tumours' were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure 'tumour' volumes both in vivo and ex vivo.

  18. Evaluation of right ventricular volume and function by 2D and 3D echocardiography compared to MRI

    DEFF Research Database (Denmark)

    Kjaergaard, Jesper; Petersen, Claus Leth; Kjaer, Andreas

    2005-01-01

    : Thirty-four subjects with (a) prior inferior ST-elevation myocardial infarction (n=17), (b) a history of pulmonary embolism and persistent dyspnea (n=7) or (c) normal subjects (n=10) had 2D and 3D echocardiography, SPECT and MRI within 24h. End-diastolic volume and peak tricuspid regurgitation velocity...... were increased in patients with a history of pulmonary embolism compared to healthy subjects, 130+/-26 ml vs. 94+/-26 ml, P... volume showed significant correlation to RV volumes by MRI. Tricuspid annular plane systolic excursion (TAPSE) had the better correlation to RVEF by MRI, r=0.48, P

  19. Novel 3D-CT evaluation of carotid stent volume: greater chronological expansion of stents in patients with vulnerable plaques.

    Science.gov (United States)

    Itami, Hisakazu; Tokunaga, Koji; Okuma, Yu; Hishikawa, Tomohito; Sugiu, Kenji; Ida, Kentaro; Date, Isao

    2013-09-01

    Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors. Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed. Stent volume gradually increased in each case and had increased by 1.04-1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period.

  20. Fat-suppressed three-dimensional fast spoiled gradient-recalled echo imaging: a modified FS 3D SPGR technique for assessment of patellofemoral joint chondromalacia.

    Science.gov (United States)

    Wang, S F; Cheng, H C; Chang, C Y

    1999-01-01

    Fast fat-suppressed (FS) three-dimensional (3D) spoiled gradient-recalled echo (SPGR) imaging of 64 articular cartilage regions in 16 patellofemoral joints was evaluated to assess its feasibility in diagnosing patellofemoral chondromalacia. It demonstrated good correlation with arthroscopic reports and took about half of the examination time that FS 3D SPGR did. This modified, faster technique has the potential to diagnose patellofemoral chondromalacia with shorter examination time than FS 3D SPGR did.

  1. Mechanical vibration compensation method for 3D+t multi-particle tracking in microscopic volumes.

    Science.gov (United States)

    Pimentel, A; Corkidi, G

    2009-01-01

    The acquisition and analysis of data in microscopic systems with spatiotemporal evolution is a very relevant topic. In this work, we describe a method to optimize an experimental setup for acquiring and processing spatiotemporal (3D+t) data in microscopic systems. The method is applied to a three-dimensional multi-tracking and analysis system of free-swimming sperm trajectories previously developed. The experimental set uses a piezoelectric device making oscillate a large focal-distance objective mounted on an inverted microscope (over its optical axis) to acquire stacks of images at a high frame rate over a depth on the order of 250 microns. A problem arise when the piezoelectric device oscillates, in such a way that a vibration is transmitted to the whole microscope, inducing undesirable 3D vibrations to the whole set. For this reason, as a first step, the biological preparation was isolated from the body of the microscope to avoid modifying the free swimming pattern of the microorganism due to the transmission of these vibrations. Nevertheless, as the image capturing device is mechanically attached to the "vibrating" microscope, the resulting acquired data are contaminated with an undesirable 3D movement that biases the original trajectory of these high speed moving cells. The proposed optimization method determines the functional form of these 3D oscillations to neutralize them from the original acquired data set. Given the spatial scale of the system, the added correction increases significantly the data accuracy. The optimized system may be very useful in a wide variety of 3D+t applications using moving optical devices.

  2. Computer-assisted operational planning for pediatric abdominal surgery. 3D-visualized MRI with volume rendering

    International Nuclear Information System (INIS)

    Guenther, P.; Holland-Cunz, S.; Waag, K.L.

    2006-01-01

    Exact surgical planning is necessary for complex operations of pathological changes in anatomical structures of the pediatric abdomen. 3D visualization and computer-assisted operational planning based on CT data are being increasingly used for difficult operations in adults. To minimize radiation exposure and for better soft tissue contrast, sonography and MRI are the preferred diagnostic methods in pediatric patients. Because of manifold difficulties 3D visualization of these MRI data has not been realized so far, even though the field of embryonal malformations and tumors could benefit from this. A newly developed and modified raycasting-based powerful 3D volume rendering software (VG Studio Max 1.2) for the planning of pediatric abdominal surgery is presented. With the help of specifically developed algorithms, a useful surgical planning system is demonstrated. Thanks to the easy handling and high-quality visualization with enormous gain of information, the presented system is now an established part of routine surgical planning. (orig.) [de

  3. [Computer-assisted operational planning for pediatric abdominal surgery. 3D-visualized MRI with volume rendering].

    Science.gov (United States)

    Günther, P; Tröger, J; Holland-Cunz, S; Waag, K L; Schenk, J P

    2006-08-01

    Exact surgical planning is necessary for complex operations of pathological changes in anatomical structures of the pediatric abdomen. 3D visualization and computer-assisted operational planning based on CT data are being increasingly used for difficult operations in adults. To minimize radiation exposure and for better soft tissue contrast, sonography and MRI are the preferred diagnostic methods in pediatric patients. Because of manifold difficulties 3D visualization of these MRI data has not been realized so far, even though the field of embryonal malformations and tumors could benefit from this.A newly developed and modified raycasting-based powerful 3D volume rendering software (VG Studio Max 1.2) for the planning of pediatric abdominal surgery is presented. With the help of specifically developed algorithms, a useful surgical planning system is demonstrated. Thanks to the easy handling and high-quality visualization with enormous gain of information, the presented system is now an established part of routine surgical planning.

  4. 2D and 3D milled surface roughness of high volume fraction SiCp/Al composites

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2015-06-01

    Full Text Available This paper presents a study on surface roughness generated by high speed milling of high volume fraction (65% silicon carbide particle-reinforced aluminum matrix (SiCp/Al composites. Typical 2D (Ra and Rz and 3D (Sa and Sq surface roughness parameters were selected to evaluate the influence of the milling parameters on the surface quality in comparison with aluminum alloy. The 3D topography of the milled surface was studied as well. The results indicate that 3D parameters (Sa and Sq are more capable to describe the influence of the milling parameters on the surface quality, and among them Sq is preferable due to its good sensitivity. Sq decreases with milling speed and increases with feed rate. The influence of axial depth of cut (ADOC is negligible.

  5. Fast automatic 3D liver segmentation based on a three-level AdaBoost-guided active shape model

    Energy Technology Data Exchange (ETDEWEB)

    He, Baochun; Huang, Cheng; Zhou, Shoujun; Hu, Qingmao; Jia, Fucang, E-mail: fc.jia@siat.ac.cn [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Sharp, Gregory [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Fang, Chihua; Fan, Yingfang [Department of Hepatology (I), Zhujiang Hospital, Southern Medical University, Guangzhou 510280 (China)

    2016-05-15

    Purpose: A robust, automatic, and rapid method for liver delineation is urgently needed for the diagnosis and treatment of liver disorders. Until now, the high variability in liver shape, local image artifacts, and the presence of tumors have complicated the development of automatic 3D liver segmentation. In this study, an automatic three-level AdaBoost-guided active shape model (ASM) is proposed for the segmentation of the liver based on enhanced computed tomography images in a robust and fast manner, with an emphasis on the detection of tumors. Methods: The AdaBoost voxel classifier and AdaBoost profile classifier were used to automatically guide three-level active shape modeling. In the first level of model initialization, fast automatic liver segmentation by an AdaBoost voxel classifier method is proposed. A shape model is then initialized by registration with the resulting rough segmentation. In the second level of active shape model fitting, a prior model based on the two-class AdaBoost profile classifier is proposed to identify the optimal surface. In the third level, a deformable simplex mesh with profile probability and curvature constraint as the external force is used to refine the shape fitting result. In total, three registration methods—3D similarity registration, probability atlas B-spline, and their proposed deformable closest point registration—are used to establish shape correspondence. Results: The proposed method was evaluated using three public challenge datasets: 3Dircadb1, SLIVER07, and Visceral Anatomy3. The results showed that our approach performs with promising efficiency, with an average of 35 s, and accuracy, with an average Dice similarity coefficient (DSC) of 0.94 ± 0.02, 0.96 ± 0.01, and 0.94 ± 0.02 for the 3Dircadb1, SLIVER07, and Anatomy3 training datasets, respectively. The DSC of the SLIVER07 testing and Anatomy3 unseen testing datasets were 0.964 and 0.933, respectively. Conclusions: The proposed automatic approach

  6. Fast automatic 3D liver segmentation based on a three-level AdaBoost-guided active shape model.

    Science.gov (United States)

    He, Baochun; Huang, Cheng; Sharp, Gregory; Zhou, Shoujun; Hu, Qingmao; Fang, Chihua; Fan, Yingfang; Jia, Fucang

    2016-05-01

    A robust, automatic, and rapid method for liver delineation is urgently needed for the diagnosis and treatment of liver disorders. Until now, the high variability in liver shape, local image artifacts, and the presence of tumors have complicated the development of automatic 3D liver segmentation. In this study, an automatic three-level AdaBoost-guided active shape model (ASM) is proposed for the segmentation of the liver based on enhanced computed tomography images in a robust and fast manner, with an emphasis on the detection of tumors. The AdaBoost voxel classifier and AdaBoost profile classifier were used to automatically guide three-level active shape modeling. In the first level of model initialization, fast automatic liver segmentation by an AdaBoost voxel classifier method is proposed. A shape model is then initialized by registration with the resulting rough segmentation. In the second level of active shape model fitting, a prior model based on the two-class AdaBoost profile classifier is proposed to identify the optimal surface. In the third level, a deformable simplex mesh with profile probability and curvature constraint as the external force is used to refine the shape fitting result. In total, three registration methods-3D similarity registration, probability atlas B-spline, and their proposed deformable closest point registration-are used to establish shape correspondence. The proposed method was evaluated using three public challenge datasets: 3Dircadb1, SLIVER07, and Visceral Anatomy3. The results showed that our approach performs with promising efficiency, with an average of 35 s, and accuracy, with an average Dice similarity coefficient (DSC) of 0.94 ± 0.02, 0.96 ± 0.01, and 0.94 ± 0.02 for the 3Dircadb1, SLIVER07, and Anatomy3 training datasets, respectively. The DSC of the SLIVER07 testing and Anatomy3 unseen testing datasets were 0.964 and 0.933, respectively. The proposed automatic approach achieves robust, accurate, and fast liver

  7. 3D Representative Volume Element Reconstruction of Fiber Composites via Orientation Tensor and Substructure Features

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Chen, Wei; Xu, Hongyi; Jin, Xuejun

    2016-01-01

    To provide a seamless integration of manufacturing processing simulation and fiber microstructure modeling, two new stochastic 3D microstructure reconstruction methods are proposed for two types of random fiber composites: random short fiber composites, and Sheet Molding Compounds (SMC) chopped fiber composites. A Random Sequential Adsorption (RSA) algorithm is first developed to embed statistical orientation information into 3D RVE reconstruction of random short fiber composites. For the SMC composites, an optimized Voronoi diagram based approach is developed for capturing the substructure features of SMC chopped fiber composites. The proposed methods are distinguished from other reconstruction works by providing a way of integrating statistical information (fiber orientation tensor) obtained from material processing simulation, as well as capturing the multiscale substructures of the SMC composites.

  8. Core design optimization by integration of a fast 3-D nodal code in a heuristic search procedure

    Energy Technology Data Exchange (ETDEWEB)

    Geemert, R. van; Leege, P.F.A. de; Hoogenboom, J.E.; Quist, A.J. [Delft University of Technology, NL-2629 JB Delft (Netherlands)

    1998-07-01

    An automated design tool is being developed for the Hoger Onderwijs Reactor (HOR) in Delft, the Netherlands, which is a 2 MWth swimming-pool type research reactor. As a black box evaluator, the 3-D nodal code SILWER, which up to now has been used only for evaluation of predetermined core designs, is integrated in the core optimization procedure. SILWER is a part of PSl's ELCOS package and features optional additional thermal-hydraulic, control rods and xenon poisoning calculations. This allows for fast and accurate evaluation of different core designs during the optimization search. Special attention is paid to handling the in- and output files for SILWER such that no adjustment of the code itself is required for its integration in the optimization programme. The optimization objective, the safety and operation constraints, as well as the optimization procedure, are discussed. (author)

  9. Core design optimization by integration of a fast 3-D nodal code in a heuristic search procedure

    International Nuclear Information System (INIS)

    Geemert, R. van; Leege, P.F.A. de; Hoogenboom, J.E.; Quist, A.J.

    1998-01-01

    An automated design tool is being developed for the Hoger Onderwijs Reactor (HOR) in Delft, the Netherlands, which is a 2 MWth swimming-pool type research reactor. As a black box evaluator, the 3-D nodal code SILWER, which up to now has been used only for evaluation of predetermined core designs, is integrated in the core optimization procedure. SILWER is a part of PSl's ELCOS package and features optional additional thermal-hydraulic, control rods and xenon poisoning calculations. This allows for fast and accurate evaluation of different core designs during the optimization search. Special attention is paid to handling the in- and output files for SILWER such that no adjustment of the code itself is required for its integration in the optimization programme. The optimization objective, the safety and operation constraints, as well as the optimization procedure, are discussed. (author)

  10. Fast Fourier transform-based solution of 2D and 3D magnetization problems in type-II superconductivity

    Science.gov (United States)

    Prigozhin, Leonid; Sokolovsky, Vladimir

    2018-05-01

    We consider the fast Fourier transform (FFT) based numerical method for thin film magnetization problems (Vestgården and Johansen 2012 Supercond. Sci. Technol. 25 104001), compare it with the finite element methods, and evaluate its accuracy. Proposed modifications of this method implementation ensure stable convergence of iterations and enhance its efficiency. A new method, also based on the FFT, is developed for 3D bulk magnetization problems. This method is based on a magnetic field formulation, different from the popular h-formulation of eddy current problems typically employed with the edge finite elements. The method is simple, easy to implement, and can be used with a general current–voltage relation; its efficiency is illustrated by numerical simulations.

  11. Fast, large field-of-view, telecentric optical-CT scanning system for 3D radiochromic dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, A; Oldham, M, E-mail: ast5@duke.ed [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)

    2010-11-01

    We describe initial experiences with an in-house, fast, large field-of-view optical-CT telecentric scanner (the Duke Large field of view Optical-CT Scanner (DLOS)). The DLOS system is designed to enable telecentric optical-CT imaging of dosimeters up to 24 cm in diameter with a spatial resolution of 1 mm{sup 3}, in approximately 10 minutes. These capabilities render the DLOS system a unique device at present. The system is a scaled up version of early prototypes in our lab. This scaling introduces several challenges, including the accurate measurement of a greatly increased range of light attenuation within the dosimeter, and the need to reduce even minor reflections and scattered light within the imaging chain. We present several corrections and techniques that enable accurate, low noise, 3D dosimetery with the DLOS system.

  12. The parallel processing system for fast 3D-CT image reconstruction by circular shifting float memory architecture

    International Nuclear Information System (INIS)

    Wang Shi; Kang Kejun; Wang Jingjin

    1996-01-01

    Computerized Tomography (CT) is expected to become an inevitable diagnostic technique in the future. However, the long time required to reconstruct an image has been one of the major drawbacks associated with this technique. Parallel process is one of the best way to solve this problem. This paper gives the architecture, hardware and software design of PIRS-4 (4-processor Parallel Image Reconstruction System), which is a parallel processing system for fast 3D-CT image reconstruction by circular shifting float memory architecture. It includes the structure and components of the system, the design of crossbar switch and details of control model, the description of RPBP image reconstruction, the choice of OS (Operate System) and language, the principle of imitating EMS, direct memory R/W of float and programming in the protect model. Finally, the test results are given

  13. Fast matrix treatment of 3-D radiative transfer in vegetation canopies: SPARTACUS-Vegetation 1.1

    Science.gov (United States)

    Hogan, Robin J.; Quaife, Tristan; Braghiere, Renato

    2018-01-01

    A fast scheme is described to compute the 3-D interaction of solar radiation with vegetation canopies. The canopy is split in the horizontal plane into one clear region and one or more vegetated regions, and the two-stream equations are used for each, but with additional terms representing lateral exchange of radiation between regions that are proportional to the area of the interface between them. The resulting coupled set of ordinary differential equations is solved using the matrix-exponential method. The scheme is compared to solar Monte Carlo calculations for idealized scenes from the RAMI4PILPS intercomparison project, for open forest canopies and shrublands both with and without snow on the ground. Agreement is good in both the visible and infrared: for the cases compared, the root-mean-squared difference in reflectance, transmittance and canopy absorptance is 0.020, 0.038 and 0.033, respectively. The technique has potential application to weather and climate modelling.

  14. Fast-electron-impact study on excitations of 4p, 4s, and 3d electrons of krypton

    International Nuclear Information System (INIS)

    Yuan Zhensheng; Zhu Linfan; Liu Xiaojing; Li Wenbin; Cheng Huadong; Xu Kezun; Zhong Zhiping

    2002-01-01

    Absolute optical oscillator strength densities for the excitations of the electrons 4p, 4s, and 3d have been measured. Their absolute optical oscillator strengths have also been obtained. An enhancement above the 4p ionization threshold in the photoabsorption spectrum was assigned as a delayed maximum which arises from the photoionization process of 4p→εd according to present Dirac-Slater calculation. In the energy region of 4s autoionization, we have observed several features that are absent in previous fast-electron-impact work, but exist in optical measurements. We clarify this discrepancy here. Two Rydberg series of optically forbidden transitions, i.e., 4s -1 ns( 1 S) (n=5,6,7) and 4s -1 nd( 1 D) (n=4,5,6,7) have been observed when the spectrometer worked at conditions with larger momentum transfers, namely, K 2 =0.23 a.u. and 0.67 a.u. Furthermore, the absolute optical oscillator strengths for the 3d excitation have been obtained

  15. 3D inverse-opal structured Li4Ti5O12 Anode for fast Li-Ion storage capabilities

    Science.gov (United States)

    Kim, Dahye; Quang, Nguyen Duc; Hien, Truong Thi; Chinh, Nguyen Duc; Kim, Chunjoong; Kim, Dojin

    2017-11-01

    Since the demand for high power Li-ion batteries (LIBs) is increasing, spinel-structured lithium titanate, Li4Ti5O12 (LTO), as the anode material has attracted great attention because of its excellent cycle retention, good thermal stability, high rate capability, and so on. However, LTO shows relatively low conductivity due to empty 3 d orbital of Ti4+ state. Nanoscale architectures can shorten electron conduction path, thus such low electronic conductivity can be overcome while Li+ can be easily accessed due to large surface area. Herein, three dimensional bicontinuous LTO electrodes were prepared via close-packed self-assembly with polystyrene (PS) spheres followed by removal of them, which leads to no blockage of Li+ ion transportation pathways as well as fast electron conduction. 3D bicontinuous LTO electrodes showed high-rate lithium storage capability (103 mAh/g at 20 C), which is promising as the power sources that require rapid electrochemical response.[Figure not available: see fulltext.

  16. Left ventricular function assessment using a fast 3D gradient echo pulse sequence: comparison to standard multi-breath hold 2D steady state free precession imaging and accounting for papillary muscles and trabeculations.

    Science.gov (United States)

    Sievers, Burkhard; Schrader, Sebastian; Rehwald, Wolfgang; Hunold, Peter; Barkhausen, Joerg; Erbel, Raimund

    2011-06-01

    Papillary muscles and trabeculae for ventricular function analysis are known to significantly contribute to accurate volume and mass measurements. Fast imaging techniques such as three-dimensional steady-state free precession (3D SSFP) are increasingly being used to speed up imaging time, but sacrifice spatial resolution. It is unknown whether 3D SSFP, despite its reduced spatial resolution, allows for exact delineation of papillary muscles and trabeculations. We therefore compared 3D SSFP ventricular function measurements to those measured from standard multi-breath hold two-dimensional steady-state free precession cine images (standard 2D SSFP). 14 healthy subjects and 14 patients with impaired left ventricularfunction underwent 1.5 Tesla cine imaging. A stack of short axis images covering the left ventricle was acquired with 2D SSFP and 3D SSFP. Left ventricular volumes, ejection fraction, and mass were determined. Analysis was performed by substracting papillary muscles and trabeculae from left ventricular volumes. In addition, reproducibility was assessed. EDV, ESV, EF, and mass were not significantly different between 2D SSFP and 3D SSFP (mean difference healthy subjects: -0.06 +/- 3.2 ml, 0.54 +/- 2.2 ml, -0.45 +/- 1.8%, and 1.13 +/- 0.8 g, respectively; patients: 1.36 +/- 2.8 ml, -0.15 3.5 ml, 0.86 +/- 2.5%, and 0.91 +/- 0.9 g, respectively; P > or = 0.095). Intra- and interobserver variability was not different for 2D SSFP (P > or = 0.64 and P > or = 0.397) and 3D SSFP (P > or = 0.53 and P > or = 0.47). Differences in volumes, EF, and mass measurements between 3D SSFP and standard 2D SSFP are very small, and not statistically significant. 3D SSFP may be used for accurate ventricular function assessment when papillary muscles and trabeculations are to be taken into account.

  17. P32INCREASED PERCENTAGE RESECTION OF TUMOUR VOLUME USING NEURONAVIGATIONAL 3D INTRAOPERATIVE ULTRASOUND: A SINGLE UNIT EXPERIENCE

    OpenAIRE

    Vaqas, B.; O'Neill, K.; Awad, M.

    2014-01-01

    INTRODUCTION: The use of intraoperative 3D navigational ultrasound (Sonowand) offers a relatively inexpensive method of obtaining imaging of intrinsic brain tumours during resection which takes in account brain shift during surgery and also allows better visualisation of the tumour margin to help control resection. We designed a study to measure the volume of tumour resection in 25 consecutive Sonowand cases compared to 25 matched non-ultrasound guided controls. METHOD: A retrospective consec...

  18. Towards a universal method for calculating hydration free energies: a 3D reference interaction site model with partial molar volume correction

    International Nuclear Information System (INIS)

    Palmer, David S; Frolov, Andrey I; Ratkova, Ekaterina L; Fedorov, Maxim V

    2010-01-01

    We report a simple universal method to systematically improve the accuracy of hydration free energies calculated using an integral equation theory of molecular liquids, the 3D reference interaction site model. A strong linear correlation is observed between the difference of the experimental and (uncorrected) calculated hydration free energies and the calculated partial molar volume for a data set of 185 neutral organic molecules from different chemical classes. By using the partial molar volume as a linear empirical correction to the calculated hydration free energy, we obtain predictions of hydration free energies in excellent agreement with experiment (R = 0.94, σ = 0.99 kcal mol -1 for a test set of 120 organic molecules). (fast track communication)

  19. A computationally efficient 3D finite-volume scheme for violent liquid–gas sloshing

    CSIR Research Space (South Africa)

    Oxtoby, Oliver F

    2015-10-01

    Full Text Available We describe a semi-implicit volume-of-fluid free-surface-modelling methodology for flow problems involving violent free-surface motion. For efficient computation, a hybrid-unstructured edge-based vertex-centred finite volume discretisation...

  20. MRT letter: Guided filtering of image focus volume for 3D shape recovery of microscopic objects.

    Science.gov (United States)

    Mahmood, Muhammad Tariq

    2014-12-01

    In this letter, a shape from focus (SFF) method is proposed that utilizes the guided image filtering to enhance the image focus volume efficiently. First, image focus volume is computed using a conventional focus measure. Then each layer of image focus volume is filtered using guided filtering. In this work, the all-in-focus image, which can be obtained from the initial focus volume, is used as guidance image. Finally, improved depth map is obtained from the filtered image focus volume by maximizing the focus measure along the optical axis. The proposed SFF method is efficient and provides better depth maps. The improved performance is highlighted by conducting several experiments using image sequences of simulated and real microscopic objects. The comparative analysis demonstrates the effectiveness of the proposed SFF method. © 2014 Wiley Periodicals, Inc.

  1. 3D medical image segmentation based on a continuous modelling of the volume

    International Nuclear Information System (INIS)

    Marque, I.

    1990-12-01

    Several medical imaging/techniques, including Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) provide 3D information of the human body by means of a stack of parallel cross-sectional images. But a more sophisticated edge detection step has to be performed when the object under study is not well defined by its characteristic density or when an analytical knowledge of the surface of the object is useful for later processings. A new method for medical image segmentation has been developed: it uses the stability and differentiability properties of a continuous modelling of the 3D data. The idea is to build a system of Ordinary Differential Equations which the stable manifold is the surface of the object we are looking for. This technique has been applied to classical edge detection operators: threshold following, laplacian, gradient maximum in its direction. It can be used in 2D as well as in 3D and has been extended to seek particular points of the surface, such as local extrema. The major advantages of this method are as follows: the segmentation and boundary following steps are performed simultaneously, an analytical representation of the surface is obtained straightforwardly and complex objects in which branching problems may occur can be described automatically. Simulations on noisy synthetic images have induced a quantization step to test the sensitiveness to noise of our method with respect to each operator, and to study the influence of all the parameters. Last, this method has been applied to numerous real clinical exams: skull or femur images provided by CT, MR images of a cerebral tumor and of the ventricular system. These results show the reliability and the efficiency of this new method of segmentation [fr

  2. 3-D inelastic analysis methods for hot section components. Volume 2: Advanced special functions models

    Science.gov (United States)

    Wilson, R. B.; Banerjee, P. K.

    1987-01-01

    This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Sections Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of computer codes that permit more accurate and efficient three-dimensional analyses of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components.

  3. A fast dual wavelength laser beam fluid-less optical CT scanner for radiotherapy 3D gel dosimetry I: design and development

    Science.gov (United States)

    Ramm, Daniel

    2018-02-01

    Three dimensional dosimetry by optical CT readout of radiosensitive gels or solids has previously been indicated as a solution for measurement of radiotherapy 3D dose distributions. The clinical uptake of these dosimetry methods has been limited, partly due to impracticalities of the optical readout such as the expertise and labour required for refractive index fluid matching. In this work a fast laser beam optical CT scanner is described, featuring fluid-less and dual wavelength operation. A second laser with a different wavelength is used to provide an alternative reference scan to the commonly used pre-irradiation scan. Transmission data for both wavelengths is effectively acquired simultaneously, giving a single scan process. Together with the elimination of refractive index fluid matching issues, scanning practicality is substantially improved. Image quality and quantitative accuracy were assessed for both dual and single wavelength methods. The dual wavelength scan technique gave improvements in uniformity of reconstructed optical attenuation coefficients in the sample 3D volume. This was due to a reduction of artefacts caused by scan to scan changes. Optical attenuation measurement accuracy was similar for both dual and single wavelength modes of operation. These results established the basis for further work on dosimetric performance.

  4. A 3-D method for delineation of activity distributions and assessment of functional organ volumes with SPECT

    International Nuclear Information System (INIS)

    Wang, Y.; Karolinska Hospital and Karolinska Inst., Stockholm; Jacobsson, H.; Jacobson, S.H.; Kimiaei, S.; Larsson, S.A.

    1995-01-01

    The distrubution volume of an organ may have a clinical impact in many cases and various methods have been designed to make volume assessments. In this paper, we describe a new method for delineation of the distribution outline and volume determination. The method is based on smoothing, differentiation, image relaxation and voxel counting of single photon emission computer tomography (SPECT) image sets with 3-D operators. A special routine corrects for the inherent thickness of the voxel-based outline. Phantom experiments, using a SPECT system with LEGP-collimator and a 64x64 acquisition matrix with 6.3x6.3 mm 2 pixel size, demonstrated good correlation between the measured and the true volumes. For volumes larger than 120 cc the correlation coefficient was 0.9999 with SE 1.0 cc and an average relative deviation of 0.49%. For volumes below 120 cc, the accuracy was impaired due to low resolution power. By improving the system spatial resolution with an LEHR-collimator and a smaller pixel-size (4.1x4.1 mm 2 ), good accuracy was achieved also for volumes in the range from 3 to 120 cc. Measurements of 15 differently shaped phantoms of volumes between 3 and 104 cc demonstrated high correlation between measured and true volumes: R=0.9921 and SE=0.74 cc (5.3%). For volumes as small as 3 and 5 cc, the difference between the true and the assessed volume was 0.6 cc. The reproducibility of the method was within 3% for volumes above 120 cc and within 7% for volumes below. Due to this accuracy, we conclude that the method can be applied for various clinical routine and research applications using SPECT. (orig.)

  5. 1H Spectroscopic Imaging of Human Brain at 3T: Comparison of Fast 3D-MRSI Techniques

    Science.gov (United States)

    Zierhut, Matthew L.; Ozturk-Isik, Esin; Chen, Albert P.; Park, Ilwoo; Vigneron, Daniel B.; Nelson, Sarah J.

    2011-01-01

    Purpose To investigate the signal-to-noise-ratio (SNR) and data quality of time-reduced 1H 3D-MRSI techniques in the human brain at 3T. Materials and Methods Techniques that were investigated included ellipsoidal k-space sampling, parallel imaging, and EPSI. The SNR values for NAA, Cho, Cre, and lactate or lipid peaks were compared after correcting for effective spatial resolution and acquisition time in a phantom and in the brains of human volunteers. Other factors considered were linewidths, metabolite ratios, partial volume effects, and subcutaneous lipid contamination. Results In volunteers, the median normalized SNR for parallel imaging data decreased by 34–42%, but could be significantly improved using regularization. The normalized signal to noise loss in flyback EPSI data was 11–18%. The effective spatial resolutions of the traditional, ellipsoidal, SENSE, and EPSI data were 1.02, 2.43, 1.03, and 1.01cm3, respectively. As expected, lipid contamination was variable between subjects but was highest for the SENSE data. Patient data obtained using the flyback EPSI method were of excellent quality. Conclusions Data from all 1H 3D-MRSI techniques were qualitatively acceptable, based upon SNR, linewidths, and metabolite ratios. The larger FOV obtained with the EPSI methods showed negligible lipid aliasing with acceptable SNR values in less than 9.5 minutes without compromising the PSF. PMID:19711396

  6. Statistical representative elementary volumes of porous media determined using greyscale analysis of 3D tomograms

    Science.gov (United States)

    Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

    2017-09-01

    Digital rock physics carries the dogmatic concept of having to segment volume images for quantitative analysis but segmentation rejects huge amounts of signal information. Information that is essential for the analysis of difficult and marginally resolved samples, such as materials with very small features, is lost during segmentation. In X-ray nanotomography reconstructions of Hod chalk we observed partial volume voxels with an abundance that limits segmentation based analysis. Therefore, we investigated the suitability of greyscale analysis for establishing statistical representative elementary volumes (sREV) for the important petrophysical parameters of this type of chalk, namely porosity, specific surface area and diffusive tortuosity, by using volume images without segmenting the datasets. Instead, grey level intensities were transformed to a voxel level porosity estimate using a Gaussian mixture model. A simple model assumption was made that allowed formulating a two point correlation function for surface area estimates using Bayes' theory. The same assumption enables random walk simulations in the presence of severe partial volume effects. The established sREVs illustrate that in compacted chalk, these simulations cannot be performed in binary representations without increasing the resolution of the imaging system to a point where the spatial restrictions of the represented sample volume render the precision of the measurement unacceptable. We illustrate this by analyzing the origins of variance in the quantitative analysis of volume images, i.e. resolution dependence and intersample and intrasample variance. Although we cannot make any claims on the accuracy of the approach, eliminating the segmentation step from the analysis enables comparative studies with higher precision and repeatability.

  7. Volume based DCE-MRI breast cancer detection with 3D visualization system

    International Nuclear Information System (INIS)

    Chia, F.K.; Sim, K.S.; Chong, S.S.; Tan, S.T.; Ting, H.Y.; Abbas, S.F.; Omar, S.

    2011-01-01

    In this paper, a computer aided design auto probing system is presented to detect breast lesions based on Dynamic contrast enhanced Magnetic resonance imaging (DCE-MRI) images. The system is proposed in order to aid the radiologists and doctors in the interpretation of MRI breast images and enhance the detection accuracy. A series of approaches are presented to enhance the detection accuracy and refine the breast region of interest (Roil) automatically. Besides, a semi-quantitative analysis is used to segment the breast lesions from selected breast Roil and classify the detected tumour is whether benign, suspicious or malignant. The entire breast Roil including the detected tumour will display in 3D. The methodology has been applied on 104 sets of digital imaging and communications in medicine (Dico) breast MRI datasets images. The biopsy results are verified by 2 radiologists from Hospital Malaysia. The experimental results are demonstrated the proposed scheme can precisely identify breast cancer regions with 93% accuracy. (author)

  8. Qualitative and quantitative assessment of wrist MRI at 3.0T - Comparison between isotropic 3D turbo spin echo and isotropic 3D fast field echo and 2D turbo spin echo

    International Nuclear Information System (INIS)

    Jung, Jee Young; Yoon, Young Cheol; Jung, Jin Young; Choe, Bong-Keun

    2013-01-01

    Background: Isotropic three-dimensional (3D) magnetic resonance imaging (MRI) has been applied to various joints. However, comparison for image quality between isotropic 3D MRI and two-dimensional (2D) turbo spin echo (TSE) sequence of the wrist at a 3T MR system has not been investigated. Purpose: To compare the image quality of isotropic 3D MRI including TSE intermediate-weighted (VISTA) sequence and fast field echo (FFE) sequence with 2D TSE intermediate-weighted sequence of the wrist joint at 3.0 T. Material and Methods: MRI was performed in 10 wrists of 10 healthy volunteers with isotropic 3D sequences (VISTA and FFE) and 2D TSE intermediate-weighted sequences at 3.0 T. The signal-to-noise ratio (SNR) was obtained by imaging phantom and noise-only image. Contrast ratios (CRs) were calculated between fluid and cartilage, triangular fibrocartilage complex (TFCC), and the scapholunate ligament. Two radiologists independently assessed the visibility of TFCC, carpal ligaments, cartilage, tendons and nerves with a four-point grading scale. Statistical analysis to compare CRs (one way ANOVA with a Tukey test) and grades of visibility (Kruskal-Wallis test) between three sequences and those for inter-observer agreement (kappa analysis) were performed. Results: The SNR of 2D TSE (46.26) was higher than those of VISTA (23.34) and 3D FFE (19.41). CRs were superior in 2D TSE than VISTA (P = 0.02) for fluid-cartilage and in 2D TSE than 3D FFE (P < 0.01) for fluid-TFCC. The visibility was best in 2D TSE (P < 0.01) for TFCC and in VISTA (P = 0.01) for scapholunate ligament. The visibility was better in 2D TSE and 3D FFE (P 0.04) for cartilage and in VISTA than 3D FFE (P < 0.01) for TFCC. The inter-observer agreement for the visibility of anatomic structures was moderate or substantial. Conclusion: Image quality of 2D TSE was superior to isotropic 3D MR imaging for cartilage, and TFCC. 3D FFE has better visibility for cartilage than VISTA and VISTA has superior visibility for

  9. Qualitative and quantitative assessment of wrist MRI at 3.0T - Comparison between isotropic 3D turbo spin echo and isotropic 3D fast field echo and 2D turbo spin echo

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jee Young [Dept. of Radiology, Chungang Univ. Hospital, School of Medicine, Chungang Univ. (Korea, Republic of); Yoon, Young Cheol [Dept. of Radiology, Samsung Medical Center, School of Medicine, Sungkyunkwan Univ. (Korea, Republic of)], e-mail: ycyoon@skku.edu; Jung, Jin Young [Dept. of Radiology, Saint Paul' s Hospital, The Catholic Univ. (Korea, Republic of); Choe, Bong-Keun [Dept. of Preventive Medicine, School of Medicine, Kyung Hee Univ., Seoul (Korea, Republic of)

    2013-04-15

    Background: Isotropic three-dimensional (3D) magnetic resonance imaging (MRI) has been applied to various joints. However, comparison for image quality between isotropic 3D MRI and two-dimensional (2D) turbo spin echo (TSE) sequence of the wrist at a 3T MR system has not been investigated. Purpose: To compare the image quality of isotropic 3D MRI including TSE intermediate-weighted (VISTA) sequence and fast field echo (FFE) sequence with 2D TSE intermediate-weighted sequence of the wrist joint at 3.0 T. Material and Methods: MRI was performed in 10 wrists of 10 healthy volunteers with isotropic 3D sequences (VISTA and FFE) and 2D TSE intermediate-weighted sequences at 3.0 T. The signal-to-noise ratio (SNR) was obtained by imaging phantom and noise-only image. Contrast ratios (CRs) were calculated between fluid and cartilage, triangular fibrocartilage complex (TFCC), and the scapholunate ligament. Two radiologists independently assessed the visibility of TFCC, carpal ligaments, cartilage, tendons and nerves with a four-point grading scale. Statistical analysis to compare CRs (one way ANOVA with a Tukey test) and grades of visibility (Kruskal-Wallis test) between three sequences and those for inter-observer agreement (kappa analysis) were performed. Results: The SNR of 2D TSE (46.26) was higher than those of VISTA (23.34) and 3D FFE (19.41). CRs were superior in 2D TSE than VISTA (P = 0.02) for fluid-cartilage and in 2D TSE than 3D FFE (P < 0.01) for fluid-TFCC. The visibility was best in 2D TSE (P < 0.01) for TFCC and in VISTA (P = 0.01) for scapholunate ligament. The visibility was better in 2D TSE and 3D FFE (P 0.04) for cartilage and in VISTA than 3D FFE (P < 0.01) for TFCC. The inter-observer agreement for the visibility of anatomic structures was moderate or substantial. Conclusion: Image quality of 2D TSE was superior to isotropic 3D MR imaging for cartilage, and TFCC. 3D FFE has better visibility for cartilage than VISTA and VISTA has superior visibility for

  10. Contour interpolated radial basis functions with spline boundary correction for fast 3D reconstruction of the human articular cartilage from MR images

    International Nuclear Information System (INIS)

    Javaid, Zarrar; Unsworth, Charles P.; Boocock, Mark G.; McNair, Peter J.

    2016-01-01

    Purpose: The aim of this work is to demonstrate a new image processing technique that can provide a “near real-time” 3D reconstruction of the articular cartilage of the human knee from MR images which is user friendly. This would serve as a point-of-care 3D visualization tool which would benefit a consultant radiologist in the visualization of the human articular cartilage. Methods: The authors introduce a novel fusion of an adaptation of the contour method known as “contour interpolation (CI)” with radial basis functions (RBFs) which they describe as “CI-RBFs.” The authors also present a spline boundary correction which further enhances volume estimation of the method. A subject cohort consisting of 17 right nonpathological knees (ten female and seven male) is assessed to validate the quality of the proposed method. The authors demonstrate how the CI-RBF method dramatically reduces the number of data points required for fitting an implicit surface to the entire cartilage, thus, significantly improving the speed of reconstruction over the comparable RBF reconstruction method of Carr. The authors compare the CI-RBF method volume estimation to a typical commercial package (3D DOCTOR), Carr’s RBF method, and a benchmark manual method for the reconstruction of the femoral, tibial, and patellar cartilages. Results: The authors demonstrate how the CI-RBF method significantly reduces the number of data points (p-value < 0.0001) required for fitting an implicit surface to the cartilage, by 48%, 31%, and 44% for the patellar, tibial, and femoral cartilages, respectively. Thus, significantly improving the speed of reconstruction (p-value < 0.0001) by 39%, 40%, and 44% for the patellar, tibial, and femoral cartilages over the comparable RBF model of Carr providing a near real-time reconstruction of 6.49, 8.88, and 9.43 min for the patellar, tibial, and femoral cartilages, respectively. In addition, it is demonstrated how the CI-RBF method matches the volume

  11. Contour interpolated radial basis functions with spline boundary correction for fast 3D reconstruction of the human articular cartilage from MR images

    Energy Technology Data Exchange (ETDEWEB)

    Javaid, Zarrar; Unsworth, Charles P., E-mail: c.unsworth@auckland.ac.nz [Department of Engineering Science, The University of Auckland, Auckland 1010 (New Zealand); Boocock, Mark G.; McNair, Peter J. [Health and Rehabilitation Research Center, Auckland University of Technology, Auckland 1142 (New Zealand)

    2016-03-15

    Purpose: The aim of this work is to demonstrate a new image processing technique that can provide a “near real-time” 3D reconstruction of the articular cartilage of the human knee from MR images which is user friendly. This would serve as a point-of-care 3D visualization tool which would benefit a consultant radiologist in the visualization of the human articular cartilage. Methods: The authors introduce a novel fusion of an adaptation of the contour method known as “contour interpolation (CI)” with radial basis functions (RBFs) which they describe as “CI-RBFs.” The authors also present a spline boundary correction which further enhances volume estimation of the method. A subject cohort consisting of 17 right nonpathological knees (ten female and seven male) is assessed to validate the quality of the proposed method. The authors demonstrate how the CI-RBF method dramatically reduces the number of data points required for fitting an implicit surface to the entire cartilage, thus, significantly improving the speed of reconstruction over the comparable RBF reconstruction method of Carr. The authors compare the CI-RBF method volume estimation to a typical commercial package (3D DOCTOR), Carr’s RBF method, and a benchmark manual method for the reconstruction of the femoral, tibial, and patellar cartilages. Results: The authors demonstrate how the CI-RBF method significantly reduces the number of data points (p-value < 0.0001) required for fitting an implicit surface to the cartilage, by 48%, 31%, and 44% for the patellar, tibial, and femoral cartilages, respectively. Thus, significantly improving the speed of reconstruction (p-value < 0.0001) by 39%, 40%, and 44% for the patellar, tibial, and femoral cartilages over the comparable RBF model of Carr providing a near real-time reconstruction of 6.49, 8.88, and 9.43 min for the patellar, tibial, and femoral cartilages, respectively. In addition, it is demonstrated how the CI-RBF method matches the volume

  12. FuncPatch: a web server for the fast Bayesian inference of conserved functional patches in protein 3D structures.

    Science.gov (United States)

    Huang, Yi-Fei; Golding, G Brian

    2015-02-15

    A number of statistical phylogenetic methods have been developed to infer conserved functional sites or regions in proteins. Many methods, e.g. Rate4Site, apply the standard phylogenetic models to infer site-specific substitution rates and totally ignore the spatial correlation of substitution rates in protein tertiary structures, which may reduce their power to identify conserved functional patches in protein tertiary structures when the sequences used in the analysis are highly similar. The 3D sliding window method has been proposed to infer conserved functional patches in protein tertiary structures, but the window size, which reflects the strength of the spatial correlation, must be predefined and is not inferred from data. We recently developed GP4Rate to solve these problems under the Bayesian framework. Unfortunately, GP4Rate is computationally slow. Here, we present an intuitive web server, FuncPatch, to perform a fast approximate Bayesian inference of conserved functional patches in protein tertiary structures. Both simulations and four case studies based on empirical data suggest that FuncPatch is a good approximation to GP4Rate. However, FuncPatch is orders of magnitudes faster than GP4Rate. In addition, simulations suggest that FuncPatch is potentially a useful tool complementary to Rate4Site, but the 3D sliding window method is less powerful than FuncPatch and Rate4Site. The functional patches predicted by FuncPatch in the four case studies are supported by experimental evidence, which corroborates the usefulness of FuncPatch. The software FuncPatch is freely available at the web site, http://info.mcmaster.ca/yifei/FuncPatch golding@mcmaster.ca Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. A novel 3D volumetric voxel registration technique for volume-view-guided image registration of multiple imaging modalities

    International Nuclear Information System (INIS)

    Li Guang; Xie Huchen; Ning, Holly; Capala, Jacek; Arora, Barbara C.; Coleman, C. Norman; Camphausen, Kevin; Miller, Robert W.

    2005-01-01

    Purpose: To provide more clinically useful image registration with improved accuracy and reduced time, a novel technique of three-dimensional (3D) volumetric voxel registration of multimodality images is developed. Methods and Materials: This technique can register up to four concurrent images from multimodalities with volume view guidance. Various visualization effects can be applied, facilitating global and internal voxel registration. Fourteen computed tomography/magnetic resonance (CT/MR) image sets and two computed tomography/positron emission tomography (CT/PET) image sets are used. For comparison, an automatic registration technique using maximization of mutual information (MMI) and a three-orthogonal-planar (3P) registration technique are used. Results: Visually sensitive registration criteria for CT/MR and CT/PET have been established, including the homogeneity of color distribution. Based on the registration results of 14 CT/MR images, the 3D voxel technique is in excellent agreement with the automatic MMI technique and is indicatory of a global positioning error (defined as the means and standard deviations of the error distribution) using the 3P pixel technique: 1.8 deg ± 1.2 deg in rotation and 2.0 ± 1.3 (voxel unit) in translation. To the best of our knowledge, this is the first time that such positioning error has been addressed. Conclusion: This novel 3D voxel technique establishes volume-view-guided image registration of up to four modalities. It improves registration accuracy with reduced time, compared with the 3P pixel technique. This article suggests that any interactive and automatic registration should be safeguarded using the 3D voxel technique

  14. Advancement of 31P Magnetic Resonance Spectroscopy Using GRAPPA Reconstruction on a 3D Volume

    Science.gov (United States)

    Clevenger, Tony

    The overall objective of this research is to improve currently available metabolic imaging techniques for clinical use in monitoring and predicting treatment response to radiation therapy in liver cancer. Liver metabolism correlates with inflammatory and neoplastic liver diseases, which alter the intracellular concentration of phosphorus- 31 (31P) metabolites [1]. It is assumed that such metabolic changes occur prior to physical changes of the tissue. Therefore, information on regional changes of 31P metabolites in the liver, obtained by Magnetic Resonance Spectroscopic Imaging (MRSI) [1,2], can help in diagnosis and follow-up of various liver diseases. Specifically, there appears to be an immediate need of this technology for both the assessment of tumor response in patients with Hepatocellular Carcinoma (HCC) treated with Stereotactic Body Radiation Therapy (SBRT) [3--5], as well as assessment of radiation toxicity, which can result in worsening liver dysfunction [6]. Pilot data from our lab has shown that 31P MRSI has the potential to identify treatment response five months sooner than conventional methods [7], and to assess the biological response of liver tissue to radiation 24 hours post radiation therapy [8]. While this data is very promising, commonly occurring drawbacks for 31P MRSI are patient discomfort due to long scan times and prone positioning within the scanner, as well as reduced data quality due to patient motion and respiration. To further advance the full potential of 31P MRSI as a clinical diagnostic tool in the management of liver cancer, this PhD research project had the following aims: I) Reduce the long acquisition time of 3D 31P MRS by formulating and imple- menting an appropriate GRAPPA undersampling scheme and reconstruction on a clinical MRI scanner II) Testing and quantitative validation of GRAPPA reconstruction on 3D 31P MRSI on developmental phantoms and healthy volunteers At completion, this work should considerably advance 31P MRSI

  15. Identifying Structure-Property Relationships Through DREAM.3D Representative Volume Elements and DAMASK Crystal Plasticity Simulations: An Integrated Computational Materials Engineering Approach

    Science.gov (United States)

    Diehl, Martin; Groeber, Michael; Haase, Christian; Molodov, Dmitri A.; Roters, Franz; Raabe, Dierk

    2017-05-01

    Predicting, understanding, and controlling the mechanical behavior is the most important task when designing structural materials. Modern alloy systems—in which multiple deformation mechanisms, phases, and defects are introduced to overcome the inverse strength-ductility relationship—give raise to multiple possibilities for modifying the deformation behavior, rendering traditional, exclusively experimentally-based alloy development workflows inappropriate. For fast and efficient alloy design, it is therefore desirable to predict the mechanical performance of candidate alloys by simulation studies to replace time- and resource-consuming mechanical tests. Simulation tools suitable for this task need to correctly predict the mechanical behavior in dependence of alloy composition, microstructure, texture, phase fractions, and processing history. Here, an integrated computational materials engineering approach based on the open source software packages DREAM.3D and DAMASK (Düsseldorf Advanced Materials Simulation Kit) that enables such virtual material development is presented. More specific, our approach consists of the following three steps: (1) acquire statistical quantities that describe a microstructure, (2) build a representative volume element based on these quantities employing DREAM.3D, and (3) evaluate the representative volume using a predictive crystal plasticity material model provided by DAMASK. Exemplarily, these steps are here conducted for a high-manganese steel.

  16. Robust processing of intracranial CT angiograms for 3D volume rendering

    International Nuclear Information System (INIS)

    Moore, E.A.; Grieve, J.P.; Jaeger, H.R.; Univ. Dept. of Neurosurgery, London

    2001-01-01

    The goal of this study was to develop a robust and simple technique for processing of cranial CT angiograms (CTA) in the clinical setting. The method described in this paper involves segmentation of the bone, then dilation of the skull by adding three or four layers of voxels. This dilated skull is subtracted from the vessels object on a voxel-by-voxel basis, allowing segmentation and subsequent display of the vessels only. For evaluation of the technique, three groups of operators processed one CTA, and the quality of the 3D views obtained and the times taken were compared. One group was given training by an expert and a ''recipe'' for guidance, the second was given only the ''recipe,'' and the third group consisted of expert operators. All operators were able to produce good or acceptable shaded-surface displays when compared with digital subtraction angiography, within 10 min for experienced users, an average of 17 min for trained operators and 26 min for those using only the recipe sheet. Using a simple scoring system for the appearance of feeding vessels and draining veins, no significant differences were found between the three levels of training and experience. This technique simplifies the processing of CTAs and is quick enough to make such examinations part of a routine clinical service. (orig.)

  17. Triangular SPECT system for 3-D total organ volume imaging: Design concept and preliminary imaging results

    International Nuclear Information System (INIS)

    Lim, C.B.; Anderson, J.; Covic, J.

    1985-01-01

    SPECT systems based on 2-D detectors for projection data collection and filtered back-projection image reconstruction have the potential for true 3-D imaging, providing contiguous slice images in any orientation. Anger camera-based SPECT systems have the natural advantage supporting planar imaging clinical procedures. However, current systems suffer from two drawbacks; poor utilization of emitted photons, and inadequate system design for SPECT. A SPECT system consisting of three rectangular cameras with radial translation would offer the variable cylindrical FOV of 25 cm to 40 cm diameter allowing close detector access to the object. This system would provide optimized imaging for both brain and body organs in terms of sensitivity and resolution. For brain imaging a tight detector triangle with fan beam collimation, matching detector UFOV to the head, allows full 2 π utilization of emitted photons, resulting in >4 times sensitivity increase over the single detector system. Minification of intrinsic detector resolution in fan beam collimation further improves system resolution. For body organ imaging the three detectors with parallel hole collimators, rotating in non-circular orbit, provide both improved resolution and three-fold sensitivity increase. Practical challenges lie in ensuring perfect image overlap from three detectors without resolution degradation and artifact generation in order to benefit from the above improvements. An experimental system has been developed to test the above imaging concept and we have successfully demonstrated the superior image quality of the overlapped images. Design concept will be presented with preliminary imaging results

  18. Measurement of left atrial volume by 2D and 3D non-contrast computed tomography compared with cardiac magnetic resonance imaging

    DEFF Research Database (Denmark)

    Fredgart, Maise Høigaard; Carter-Storch, Rasmus; Møller, Jacob Eifer

    2018-01-01

    Background: Cardiac magnetic resonance imaging (MRI) is considered the gold standard for assessment of left atrial (LA) volume. We assessed the feasibility of evaluating LA volume using 3D non-contrast computed tomography (NCCT). Furthermore, since manual tracing of LA volume is time consuming, we...... evaluated the accuracy of the LA area using 2D NCCT imaging for LA volume assessment. Methods: MRI and NCCT imaging were performed in 69 patients before and one year after aortic valve replacement. In 3D MRI and 3D NCCT, each slice was manually traced, excluding the pulmonary veins and atrial appendage...

  19. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling.

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C; Joyce, Kevin P; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing ([Formula: see text] for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining [Formula: see text] compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to [Formula: see text]. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple [Formula: see text] correction improved agreement with experiment from [Formula: see text] to [Formula: see text], despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  20. SAMPL5: 3D-RISM partition coefficient calculations with partial molar volume corrections and solute conformational sampling

    Science.gov (United States)

    Luchko, Tyler; Blinov, Nikolay; Limon, Garrett C.; Joyce, Kevin P.; Kovalenko, Andriy

    2016-11-01

    Implicit solvent methods for classical molecular modeling are frequently used to provide fast, physics-based hydration free energies of macromolecules. Less commonly considered is the transferability of these methods to other solvents. The Statistical Assessment of Modeling of Proteins and Ligands 5 (SAMPL5) distribution coefficient dataset and the accompanying explicit solvent partition coefficient reference calculations provide a direct test of solvent model transferability. Here we use the 3D reference interaction site model (3D-RISM) statistical-mechanical solvation theory, with a well tested water model and a new united atom cyclohexane model, to calculate partition coefficients for the SAMPL5 dataset. The cyclohexane model performed well in training and testing (R=0.98 for amino acid neutral side chain analogues) but only if a parameterized solvation free energy correction was used. In contrast, the same protocol, using single solute conformations, performed poorly on the SAMPL5 dataset, obtaining R=0.73 compared to the reference partition coefficients, likely due to the much larger solute sizes. Including solute conformational sampling through molecular dynamics coupled with 3D-RISM (MD/3D-RISM) improved agreement with the reference calculation to R=0.93. Since our initial calculations only considered partition coefficients and not distribution coefficients, solute sampling provided little benefit comparing against experiment, where ionized and tautomer states are more important. Applying a simple pK_{ {a}} correction improved agreement with experiment from R=0.54 to R=0.66, despite a small number of outliers. Better agreement is possible by accounting for tautomers and improving the ionization correction.

  1. The Development of a 3D LADAR Simulator Based on a Fast Target Impulse Response Generation Approach

    Science.gov (United States)

    Al-Temeemy, Ali Adnan

    2017-09-01

    A new laser detection and ranging (LADAR) simulator has been developed, using MATLAB and its graphical user interface, to simulate direct detection time of flight LADAR systems, and to produce 3D simulated scanning images under a wide variety of conditions. This simulator models each stage from the laser source to data generation and can be considered as an efficient simulation tool to use when developing LADAR systems and their data processing algorithms. The novel approach proposed for this simulator is to generate the actual target impulse response. This approach is fast and able to deal with high scanning requirements without losing the fidelity that accompanies increments in speed. This leads to a more efficient LADAR simulator and opens up the possibility for simulating LADAR beam propagation more accurately by using a large number of laser footprint samples. The approach is to select only the parts of the target that lie in the laser beam angular field by mathematically deriving the required equations and calculating the target angular ranges. The performance of the new simulator has been evaluated under different scanning conditions, the results showing significant increments in processing speeds in comparison to conventional approaches, which are also used in this study as a point of comparison for the results. The results also show the simulator's ability to simulate phenomena related to the scanning process, for example, type of noise, scanning resolution and laser beam width.

  2. Usefulness of PC based 3D volume rendering technique in the evaluation of suspected aneurysm on brain MRA

    International Nuclear Information System (INIS)

    Baek, Seung Il; Lee, Ghi Jai; Shim, Jae Chan; Bang, Sun Woo; Ryu, Seok Jong; Kim, Ho Kyun

    2002-01-01

    To evaluated usefulness of volume rending technique using 3D visualization software on PC in patients with suspected intracranial aneurysm on brain MRA. We analyzed prospectively 21 patients with suspected aneurysms on the routine MIP images which were obtained 15 .deg. C increment along axial and sagittal plane, among 135 patients in whom brain MRA was done due to stroke symptoms for recent 5 months. The locations were the anterior communicating artery (A-com) in 8 patients, the posterior communicating artery (P-com) in 3, the ICA bifurcation in 5, the MCA bifurcation in 4, and the basilar tip in one. Male to female ratio was 14:7 and mean age was 62 years. MRA source images were sent to PC through LAN, and the existence of aneurysm was evaluated with volume rendering technique using 3D visualization software on PC. The presence or absence of aneurysm on MIP and volume rendering images was decided by the consensus of two radiologists. We found the aneurysms with volume rendering technique, from 1 patient among 8 patients with suspected aneurysm at A-com and also 1 patient among 3 patients with suspected aneurysm at P=com on routine MIP images. Confirmative angiography and interventional procedures were done in these 2 patients. The causes for mimicking the aneurysm on MIP were flow displacement artifact in 9, normal P-com infundibulum in 2, and overlapped or narrowed vessels in 8 patients, and among them confirmative angiography was done in 2 patient. Volume rendering technique using visualization software on PC is useful to scrutinize the suspected aneurysm on routine MIP images and to avoid further invasive angiography

  3. Octanol-Water Partition Coefficient from 3D-RISM-KH Molecular Theory of Solvation with Partial Molar Volume Correction.

    Science.gov (United States)

    Huang, WenJuan; Blinov, Nikolay; Kovalenko, Andriy

    2015-04-30

    The octanol-water partition coefficient is an important physical-chemical characteristic widely used to describe hydrophobic/hydrophilic properties of chemical compounds. The partition coefficient is related to the transfer free energy of a compound from water to octanol. Here, we introduce a new protocol for prediction of the partition coefficient based on the statistical-mechanical, 3D-RISM-KH molecular theory of solvation. It was shown recently that with the compound-solvent correlation functions obtained from the 3D-RISM-KH molecular theory of solvation, the free energy functional supplemented with the correction linearly related to the partial molar volume obtained from the Kirkwood-Buff/3D-RISM theory, also called the "universal correction" (UC), provides accurate prediction of the hydration free energy of small compounds, compared to explicit solvent molecular dynamics [ Palmer , D. S. ; J. Phys.: Condens. Matter 2010 , 22 , 492101 ]. Here we report that with the UC reparametrized accordingly this theory also provides an excellent agreement with the experimental data for the solvation free energy in nonpolar solvent (1-octanol) and so accurately predicts the octanol-water partition coefficient. The performance of the Kovalenko-Hirata (KH) and Gaussian fluctuation (GF) functionals of the solvation free energy, with and without UC, is tested on a large library of small compounds with diverse functional groups. The best agreement with the experimental data for octanol-water partition coefficients is obtained with the KH-UC solvation free energy functional.

  4. Inter-Scan Reproducibility of Carotid Plaque Volume Measurements by 3-D Ultrasound

    DEFF Research Database (Denmark)

    Sandholt, Benjamin V; Collet-Billon, Antoine; Entrekin, Robert

    2018-01-01

    (PPV) measure centered on MPT. Total plaque volume (TPV), PPV from a 10-mm segment and MPT were measured using dedicated semi-automated software on 38 plaques from 26 patients. Inter-scan reproducibility was assessed using the t-test, Bland-Altman plots and Pearson's correlation coefficient....... There was a mean difference of 0.01 mm in MPT (limits of agreement: -0.45 to 0.42 mm, Pearson's correlation coefficient: 0.96). Both volume measurements exhibited high reproducibility, with PPV being superior (limits of agreement: -35.3 mm3to 33.5 mm3, Pearson's correlation coefficient: 0.96) to TPV (limits...... of agreement: -88.2 to 61.5 mm3, Pearson's correlation coefficient: 0.91). The good reproducibility revealed by the present results encourages future studies on establishing plaque quantification as part of cardiovascular risk assessment and for follow-up of disease progression over time....

  5. 3D core burnup studies in 500 MWe Indian prototype fast breeder reactor to attain enhanced core burnup

    International Nuclear Information System (INIS)

    Choudhry, Nakul; Riyas, A.; Devan, K.; Mohanakrishnan, P.

    2013-01-01

    Highlights: ► Enhanced burnup potential of existing prototype fast breeder reactor core is studied. ► By increasing the Pu enrichment, fuel burnup can be increased in existing PFBR core. ► Enhanced burnup increase economy and reduce load of fuel fabrication and reprocessing. ► Beginning of life reactivity is suppressed by increasing the number of diluents. ► Absorber rod worth requirements can be achieved by increasing 10 B enrichment. -- Abstract: Fast breeder reactors are capable of producing high fuel burnup because of higher internal breeding of fissile material and lesser parasitic capture of neutrons in the core. As these reactors need high fissile enrichment, high fuel burnup is desirable to be cost effective and to reduce the load on fuel reprocessing and fabrication plants. A pool type, liquid sodium cooled, mixed (Pu–U) oxide fueled 500 MWe prototype fast breeder reactor (PFBR), under construction at Kalpakkam is designed for a peak burnup of 100 GWd/t. This limitation on burnup is purely due to metallurgical properties of structural materials like clad and hexcan to withstand high neutron fluence, and not by the limitation on the excess reactivity available in the core. The 3D core burnup studies performed earlier for approach to equilibrium core of PFBR is continued to demonstrate the burnup potential of existing PFBR core. To increase the fuel burnup of PFBR, plutonium oxide enrichment is increased from 20.7%/27.7% to 22.1%/29.4% of core-1/core-2 which resulted in cycle length increase from 180 to 250 effective full power days (efpd), so that the peak fuel burnup increases from 100 to 134 GWd/t, keeping all the core parameters under allowed safety limits. Number of diluents subassemblies is increased from eight to twelve at beginning of life core to bring down the initial core excess reactivity. PFBR refueling is revised to accommodate twelve diluents. Increase of 10 B enrichment in control safety rods (CSRs) and diverse safety rods (DSRs

  6. Rapid 3D in vivo 1H human lung respiratory imaging at 1.5 T using ultra-fast balanced steady-state free precession.

    Science.gov (United States)

    Pusterla, Orso; Bauman, Grzegorz; Wielpütz, Mark O; Nyilas, Sylvia; Latzin, Philipp; Heussel, Claus P; Bieri, Oliver

    2017-09-01

    To introduce a reproducible, nonenhanced 1H MRI method for rapid in vivo functional assessment of the whole lung at 1.5 Tesla (T). At different respiratory volumes, the pulmonary signal of ultra-fast steady-state free precession (ufSSFP) follows an adapted sponge model, characterized by a respiratory index α. From the model, α reflects local ventilation-related information, is virtually independent from the lung density and thus from the inspiratory phase and breathing amplitude. Respiratory α-mapping is evaluated for healthy volunteers and patients with obstructive lung disease from a set of five consecutive 3D ultra-fast steady-state free precession (ufSSFP) scans performed in breath-hold and at different inspiratory volumes. For the patients, α-maps were compared with CT, dynamic contrast-enhanced MRI (DCE-MRI), and Fourier decomposition (FD). In healthy volunteers, respiratory α-maps showed good reproducibility and were homogeneous on iso-gravitational planes, but showed a gravity-dependent respiratory gradient. In patients with obstructive pulmonary disease, the functional impairment observed in respiratory α-maps was associated with emphysematous regions present on CT images, perfusion defects observable on DCE-MRI, and impairments visualized on FD ventilation and perfusion maps. Respiratory α-mapping derived from multivolumetric ufSSFP provides insights into functional lung impairment and may serve as a reproducible and normative measure for clinical studies. Magn Reson Med 78:1059-1069, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  7. MO-G-BRF-07: Anomalously Fast Diffusion of Carbon Nanotubes Carriers in 3D Tissue Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y; Bahng, J; Kotov, N [University of Michigan, Ann Arbor, MI (United States)

    2014-06-15

    Purpose: We aim to investigate and understand diffusion process of carbon nanotubes (CNTs) and other nanoscale particles in tissue and organs. Methods: In this research, we utilized a 3D model tissue of hepatocellular carcinoma (HCC)cultured in inverted colloidal crystal (ICC) scaffolds to compare the diffusivity of CNTs with small molecules such as Rhodamine and FITC in vitro, and further investigated the transportation of CNTs with and without targeting ligand, TGFβ1. The real-time permeation profiles of CNTs in HCC tissue model with high temporal and spatial resolution was demonstrated by using standard confocal microscopy. Quantitative analysis of the diffusion process in 3D was carried out using luminescence intensity in a series of Z-stack images obtained for different time points of the diffusion process after initial addition of CNTs or small molecules to the cell culture and the image data was analyzed by software ImageJ and Mathematica. Results: CNTs display diffusion rate in model tissues substantially faster than small molecules of the similar charge such as FITC, and the diffusion rate of CNTs are significantly enhanced with targeting ligand, TGFβ1. Conclusion: In terms of the advantages of in-vitro model, we were able to have access to measuring the rate of CNT penetration at designed conditions with variable parameters. And the findings by using this model, changed our understanding about advantages of CNTs as nanoscale drug carriers and provides design principles for making new drug carriers for both treatment and diagnostics. Additionally the fast diffusion opens the discussion of the best possible drug carriers to reach deep parts of cancerous tissues, which is often a prerequisite for successful cancer treatment. This work was supported by the Center for Photonic and Multiscale Nanomaterials funded by National Science Foundation Materials Research Science and Engineering Center program DMR 1120923. The work was also partially supported by NSF

  8. MO-G-BRF-07: Anomalously Fast Diffusion of Carbon Nanotubes Carriers in 3D Tissue Model

    International Nuclear Information System (INIS)

    Wang, Y; Bahng, J; Kotov, N

    2014-01-01

    Purpose: We aim to investigate and understand diffusion process of carbon nanotubes (CNTs) and other nanoscale particles in tissue and organs. Methods: In this research, we utilized a 3D model tissue of hepatocellular carcinoma (HCC)cultured in inverted colloidal crystal (ICC) scaffolds to compare the diffusivity of CNTs with small molecules such as Rhodamine and FITC in vitro, and further investigated the transportation of CNTs with and without targeting ligand, TGFβ1. The real-time permeation profiles of CNTs in HCC tissue model with high temporal and spatial resolution was demonstrated by using standard confocal microscopy. Quantitative analysis of the diffusion process in 3D was carried out using luminescence intensity in a series of Z-stack images obtained for different time points of the diffusion process after initial addition of CNTs or small molecules to the cell culture and the image data was analyzed by software ImageJ and Mathematica. Results: CNTs display diffusion rate in model tissues substantially faster than small molecules of the similar charge such as FITC, and the diffusion rate of CNTs are significantly enhanced with targeting ligand, TGFβ1. Conclusion: In terms of the advantages of in-vitro model, we were able to have access to measuring the rate of CNT penetration at designed conditions with variable parameters. And the findings by using this model, changed our understanding about advantages of CNTs as nanoscale drug carriers and provides design principles for making new drug carriers for both treatment and diagnostics. Additionally the fast diffusion opens the discussion of the best possible drug carriers to reach deep parts of cancerous tissues, which is often a prerequisite for successful cancer treatment. This work was supported by the Center for Photonic and Multiscale Nanomaterials funded by National Science Foundation Materials Research Science and Engineering Center program DMR 1120923. The work was also partially supported by NSF

  9. 3D Volumetry and its Correlation Between Postoperative Gastric Volume and Excess Weight Loss After Sleeve Gastrectomy.

    Science.gov (United States)

    Hanssen, Andrés; Plotnikov, Sergio; Acosta, Geylor; Nuñez, José Tomas; Haddad, José; Rodriguez, Carmen; Petrucci, Claudia; Hanssen, Diego; Hanssen, Rafael

    2018-03-01

    The volume of the postoperative gastric remnant is a key factor in excess weight loss (EWL) after sleeve gastrectomy (SG). Traditional methods to estimate gastric volume (GV) after bariatric procedures are often inaccurate; usually conventional biplanar contrast studies are used. Thirty patients who underwent SG were followed prospectively and evaluated at 6 months after the surgical procedure, performing 3D CT reconstruction and gastric volumetry, to establish its relationship with EWL. The gastric remnant was distended with effervescent sodium bicarbonate given orally. Helical CT images were acquired and reconstructed; GV was estimated with the software of the CT device. The relationship between GV and EWL was analyzed. The study allowed estimating the GV in all patients. A dispersion diagram showed an inverse relationship between GV and %EWL. 55.5% of patients with GV ≤ 100 ml had %EWL 25-75% and 38.8% had an %EWL above 75% and patients with GV ≥ 100 ml had an %EWL under 25% (50% of patients) or between 25 and 75% (50% of this group). The Pearson's correlation coefficient was R = 6.62, with bilateral significance (p ≤ .01). The Chi-square result correlating GV and EWL showed a significance of .005 (p ≤ .01). The 3D reconstructions showed accurately the shape and anatomic details of the gastric remnant. 3D volumetry CT scans accurately estimate GV after SG. A significant relationship between GV and EWL 6 months after SG was established, seeming that GV ≥ 100 ml at 6 months of SG is associated with poor EWL.

  10. Effect of routine preoperative fasting on residual gastric volume and ...

    African Journals Online (AJOL)

    2016-02-10

    Feb 10, 2016 ... Key words: Fasting, myomectomy, pH, residual gastric volume. Date of Acceptance: ... gastric volume and acid in patients undergoing myomectomy. Niger J Clin ..... of gastric residual volume: A simulated, controlled study.

  11. On 'light' fermions and proton stability in 'big divisor' D3/D7 large volume compactifications

    International Nuclear Information System (INIS)

    Misra, Aalok; Shukla, Pramod

    2011-01-01

    Building on our earlier work (Misra and Shukla, Nucl. Phys. B 827:112, 2010; Phys. Lett. B 685:347-352, 2010), we show the possibility of generating ''light'' fermion mass scales of MeV-GeV range (possibly related to the first two generations of quarks/leptons) as well as eV (possibly related to first two generations of neutrinos) in type IIB string theory compactified on Swiss-Cheese orientifolds in the presence of a mobile space-time filling D3-brane restricted to (in principle) stacks of fluxed D7-branes wrapping the ''big'' divisor Σ B . This part of the paper is an expanded version of the latter half of Sect. 3 of a published short invited review (Misra, Mod. Phys. Lett. A 26:1, 2011) written by one of the authors [AM ]. Further, we also show that there are no SUSY GUT-type dimension-five operators corresponding to proton decay, and we estimate the proton lifetime from a SUSY GUT-type four-fermion dimension-six operator to be 10 61 years. Based on GLSM calculations in (Misra and Shukla, Nucl. Phys. B 827:112, 2010) for obtaining the geometric Kaehler potential for the ''big divisor,'' using further the Donaldson's algorithm, we also briefly discuss in the first of the two appendices the metric for the Swiss-Cheese Calabi-Yau used, which we obtain and which becomes Ricci flat in the large-volume limit. (orig.)

  12. On `light' fermions and proton stability in `big divisor' D3/ D7 large volume compactifications

    Science.gov (United States)

    Misra, Aalok; Shukla, Pramod

    2011-06-01

    Building on our earlier work (Misra and Shukla, Nucl. Phys. B 827:112, 2010; Phys. Lett. B 685:347-352, 2010), we show the possibility of generating "light" fermion mass scales of MeV-GeV range (possibly related to the first two generations of quarks/leptons) as well as eV (possibly related to first two generations of neutrinos) in type IIB string theory compactified on Swiss-Cheese orientifolds in the presence of a mobile space-time filling D3-brane restricted to (in principle) stacks of fluxed D7-branes wrapping the "big" divisor Σ B . This part of the paper is an expanded version of the latter half of Sect. 3 of a published short invited review (Misra, Mod. Phys. Lett. A 26:1, 2011) written by one of the authors [AM]. Further, we also show that there are no SUSY GUT-type dimension-five operators corresponding to proton decay, and we estimate the proton lifetime from a SUSY GUT-type four-fermion dimension-six operator to be 1061 years. Based on GLSM calculations in (Misra and Shukla, Nucl. Phys. B 827:112, 2010) for obtaining the geometric Kähler potential for the "big divisor," using further the Donaldson's algorithm, we also briefly discuss in the first of the two appendices the metric for the Swiss-Cheese Calabi-Yau used, which we obtain and which becomes Ricci flat in the large-volume limit.

  13. Determination of quantitative tissue composition by iterative reconstruction on 3D DECT volumes

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, Maria [Linkoeping Univ. (Sweden). Dept. of Electrical Engineering; Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV); Malusek, Alexandr [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV); Nuclear Physics Institute AS CR, Prague (Czech Republic). Dept. of Radiation Dosimetry; Muhammad, Arif [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Carlsson, Gudrun Alm [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV)

    2011-07-01

    Quantitative tissue classification using dual-energy CT has the potential to improve accuracy in radiation therapy dose planning as it provides more information about material composition of scanned objects than the currently used methods based on single-energy CT. One problem that hinders successful application of both single- and dual-energy CT is the presence of beam hardening and scatter artifacts in reconstructed data. Current pre- and post-correction methods used for image reconstruction often bias CT attenuation values and thus limit their applicability for quantitative tissue classification. Here we demonstrate simulation studies with a novel iterative algorithm that decomposes every soft tissue voxel into three base materials: water, protein, and adipose. The results demonstrate that beam hardening artifacts can effectively be removed and accurate estimation of mass fractions of each base material can be achieved. Our iterative algorithm starts with calculating parallel projections on two previously reconstructed DECT volumes reconstructed from fan-beam or helical projections with small conebeam angle. The parallel projections are then used in an iterative loop. Future developments include segmentation of soft and bone tissue and subsequent determination of bone composition. (orig.)

  14. Prostate and seminal vesicle volume based consideration of prostate cancer patients for treatment with 3D-conformal or intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Nandanuri M. S.; Nori, Dattatreyudu; Chang, Hyesook; Lange, Christopher S.; Ravi, Akkamma [Department of Radiation Oncology, New York Hospital Queens, Flushing, New York 11355 (United States); Department of Radiation Oncology, State University of New York Downstate Medical Center, Brooklyn, New York 11203 (United States); Department of Radiation Oncology, New York Hospital Queens, Flushing, New York 11355 (United States)

    2010-07-15

    Purpose: The purpose of this article was to determine the suitability of the prostate and seminal vesicle volumes as factors to consider patients for treatment with image-guided 3D-conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT), using common dosimetry parameters as comparison tools. Methods: Dosimetry of 3D and IMRT plans for 48 patients was compared. Volumes of prostate, SV, rectum, and bladder, and prescriptions were the same for both plans. For both 3D and IMRT plans, expansion margins to prostate+SV (CTV) and prostate were 0.5 cm posterior and superior and 1 cm in other dimensions to create PTV and CDPTV, respectively. Six-field 3D plans were prepared retrospectively. For 3D plans, an additional 0.5 cm margin was added to PTV and CDPTV. Prescription for both 3D and IMRT plans was the same: 45 Gy to CTV followed by a 36 Gy boost to prostate. Dosimetry parameters common to 3D and IMRT plans were used for comparison: Mean doses to prostate, CDPTV, SV, rectum, bladder, and femurs; percent volume of rectum and bladder receiving 30 (V30), 50 (V50), and 70 Gy (V70), dose to 30% of rectum and bladder, minimum and maximum point dose to CDPTV, and prescription dose covering 95% of CDPTV (D95). Results: When the data for all patients were combined, mean dose to prostate and CDPTV was higher with 3D than IMRT plans (P<0.01). Mean D95 to CDPTV was the same for 3D and IMRT plans (P>0.2). On average, among all cases, the minimum point dose was less for 3D-CRT plans and the maximum point dose was greater for 3D-CRT than for IMRT (P<0.01). Mean dose to 30% rectum with 3D and IMRT plans was comparable (P>0.1). V30 was less (P<0.01), V50 was the same (P>0.2), and V70 was more (P<0.01) for rectum with 3D than IMRT plans. Mean dose to bladder was less with 3D than IMRT plans (P<0.01). V30 for bladder with 3D plans was less than that of IMRT plans (P<0.01). V50 and V70 for 3D plans were the same for 3D and IMRT plans (P>0.2). Mean dose to femurs

  15. Fast in vivo volume dose reconstruction via reference dose perturbation

    International Nuclear Information System (INIS)

    Lu, Weiguo; Chen, Mingli; Mo, Xiaohu; Parnell, Donald; Olivera, Gustavo; Galmarini, Daniel

    2014-01-01

    Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

  16. SU-E-J-251: Fast MR-Based DRR Generation Using Highly Undersampled 3D Radial Trajectories

    International Nuclear Information System (INIS)

    Pereira, G; Traughber, B; Traughber, M; Hu, L; Su, K; Muzic, R

    2014-01-01

    Purpose: The construction of a digitally reconstructed radiograph (DRR) from a magnetic resonance image (MRI) is possible if the cortical bone signal can be acquired and separated from air and soft tissue. This may be accomplished by subtracting a long echo-time, in-phase, gradient echo (GRE) image volume from an ultra-short echo time free induction decay (FID) image to produce a bone-enhanced (BE) image that reveals cortical bone. One limitation of this approach is the length of time required for data acquisition, which can limit the quality of the DRRs due to patient and organ motion. This study aimed to significantly reduce the acquisition time without compromising DRR quality. Methods: Brain data were acquired from two volunteers using a 3T MR scanner (Ingenia, Philips Healthcare). The FID and GRE images were acquired in a single acquisition using a 3D radial readout sequence with the following parameters: TE1=0.142ms (ultra-short), TE2=2.197ms (nearly in-phase), 2*2*2mm3 isotropic voxels, 250*250*250mm3 FOV. To reduce the acquisition time, k-space was sampled at 75, 50 and 25% of a full 3D sphere . The TE2 image was subtracted from the TE1 image to generate the BE images. The BE images were used to generate DRRs using the Pinnacle treatment planning system (Philips-version 9.2). The quality of the DRRs was evaluated qualitatively by 5 board certified medical physicists for clinical usefulness. Results: The acquisition time for 75, 50 and 25% sampling schemes were 219s, 146s, and 73s, respectively, the latter of which was a four-fold reduction in scan time compared to a 300s fully-sampled acquisition. All DRRs obtained were of acceptable quality and were shown to have sufficient information for clinical 2D image matching. Conclusion: Undersampling k-space while maintaining the same range of frequency information results in significantly reduced scan time and clinically acceptable DRR image quality. Drs. B Traughber and R Muzic have research support from Philips

  17. Computer-aided detection of lung nodules via 3D fast radial transform, scale space representation, and Zernike MIP classification.

    Science.gov (United States)

    Riccardi, Alessandro; Petkov, Todor Sergueev; Ferri, Gianluca; Masotti, Matteo; Campanini, Renato

    2011-04-01

    The authors presented a novel system for automated nodule detection in lung CT exams. The approach is based on (1) a lung tissue segmentation preprocessing step, composed of histogram thresholding, seeded region growing, and mathematical morphology; (2) a filtering step, whose aim is the preliminary detection of candidate nodules (via 3D fast radial filtering) and estimation of their geometrical features (via scale space analysis); and (3) a false positive reduction (FPR) step, comprising a heuristic FPR, which applies thresholds based on geometrical features, and a supervised FPR, which is based on support vector machines classification, which in turn, is enhanced by a feature extraction algorithm based on maximum intensity projection processing and Zernike moments. The system was validated on 154 chest axial CT exams provided by the lung image database consortium public database. The authors obtained correct detection of 71% of nodules marked by all radiologists, with a false positive rate of 6.5 false positives per patient (FP/patient). A higher specificity of 2.5 FP/patient was reached with a sensitivity of 60%. An independent test on the ANODE09 competition database obtained an overall score of 0.310. The system shows a novel approach to the problem of lung nodule detection in CT scans: It relies on filtering techniques, image transforms, and descriptors rather than region growing and nodule segmentation, and the results are comparable to those of other recent systems in literature and show little dependency on the different types of nodules, which is a good sign of robustness.

  18. Volume of myocardium perfused by coronary artery branches as estimated from 3D micro-CT images of rat hearts

    Science.gov (United States)

    Lund, Patricia E.; Naessens, Lauren C.; Seaman, Catherine A.; Reyes, Denise A.; Ritman, Erik L.

    2000-04-01

    Average myocardial perfusion is remarkably consistent throughout the heart wall under resting conditions and the velocity of blood flow is fairly reproducible from artery to artery. Based on these observations, and the fact that flow through an artery is the product of arterial cross-sectional area and blood flow velocity, we would expect the volume of myocardium perfused to be proportional to the cross-sectional area of the coronary artery perfusing that volume of myocardium. This relationship has been confirmed by others in pigs, dogs and humans. To test the body size-dependence of this relationship we used the hearts from rats, 3 through 25 weeks of age. The coronary arteries were infused with radiopaque microfil polymer and the hearts scanned in a micro- CT scanner. Using these 3D images we measured the volume of myocardium and the arterial cross-sectional area of the artery that perfused that volume of myocardium. The average constant of proportionality was found to be 0.15 +/- 0.08 cm3/mm2. Our data showed no statistically different estimates of the constant of proportionality in the rat hearts of different ages nor between the left and right coronary arteries. This constant is smaller than that observed in large animals and humans, but this difference is consistent with the body mass-dependence on metabolic rate.

  19. A volume of intersection approach for on-the-fly system matrix calculation in 3D PET image reconstruction

    International Nuclear Information System (INIS)

    Lougovski, A; Hofheinz, F; Maus, J; Schramm, G; Will, E; Hoff, J van den

    2014-01-01

    The aim of this study is the evaluation of on-the-fly volume of intersection computation for system’s geometry modelling in 3D PET image reconstruction. For this purpose we propose a simple geometrical model in which the cubic image voxels on the given Cartesian grid are approximated with spheres and the rectangular tubes of response (ToRs) are approximated with cylinders. The model was integrated into a fully 3D list-mode PET reconstruction for performance evaluation. In our model the volume of intersection between a voxel and the ToR is only a function of the impact parameter (the distance between voxel centre to ToR axis) but is independent of the relative orientation of voxel and ToR. This substantially reduces the computational complexity of the system matrix calculation. Based on phantom measurements it was determined that adjusting the diameters of the spherical voxel size and the ToR in such a way that the actual voxel and ToR volumes are conserved leads to the best compromise between high spatial resolution, low noise, and suppression of Gibbs artefacts in the reconstructed images. Phantom as well as clinical datasets from two different PET systems (Siemens ECAT HR + and Philips Ingenuity-TF PET/MR) were processed using the developed and the respective vendor-provided (line of intersection related) reconstruction algorithms. A comparison of the reconstructed images demonstrated very good performance of the new approach. The evaluation showed the respective vendor-provided reconstruction algorithms to possess 34–41% lower resolution compared to the developed one while exhibiting comparable noise levels. Contrary to explicit point spread function modelling our model has a simple straight-forward implementation and it should be easy to integrate into existing reconstruction software, making it competitive to other existing resolution recovery techniques. (paper)

  20. Enabling 3D Tele-Immersion with Live Reconstructed Mesh Geometry with Fast Mesh Compression and Linear Rateless Coding

    NARCIS (Netherlands)

    R.N. Mekuria (Rufael); M. Sanna (Michele); E Izquierdo (Ebroul); D.C.A. Bulterman (Dick); P.S. Cesar Garcia (Pablo Santiago)

    2014-01-01

    htmlabstract3D Tele-immersion enables participants in remote locations to share, in real-time, an activity. It offers users interactive and immersive experiences, but it challenges current media streaming solutions. Work in the past has mainly focused on the efficient delivery of image-based 3D

  1. Enabling 3D Tele-Immersion with Live Reconstructed Mesh Geometry with Fast Mesh Compression and Linear Rateless Coding

    NARCIS (Netherlands)

    Mekuria, R.; Sanna, M.; Izquierdo, E; Bulterman, D.; Garcia, P.

    2014-01-01

    3-D tele-immersion (3DTI) enables participants in remote locations to share, in real time, an activity. It offers users interactive and immersive experiences, but it challenges current media-streaming solutions. Work in the past has mainly focused on the efficient delivery of image-based 3-D videos

  2. The Lidar Cyclops Syndrome Bypassed: 3D Wind Field Measurements from a Turbine mounted Lidar in combination with a fast CFD solver

    DEFF Research Database (Denmark)

    Mikkelsen, Torben Krogh; Astrup, Poul; van Dooren, Marijn Floris

    as the “Lidar Cyclops syndrome” with reference to the one-eyed Cyclops in old Greek mythology. However, by feeding a single lidar’s line-of-sight (LOS) rotor plane scanned wind speeds to a fast CFD solver, it has been possible to determine the entire 3D velocity vectors at each measurement point consistent...

  3. Cranial nerve assessment in cavernous sinus tumors with contrast-enhanced 3D fast-imaging employing steady-state acquisition MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Shiori; Aoki, Shigeki; Ohtomo, Kuni [University of Tokyo, Department of Radiology, Graduate School of Medicine, Bunkyo-ku, Tokyo (Japan)

    2009-07-15

    The purpose of this study is to apply contrast-enhanced 3D fast-imaging employing steady-state acquisition (3D-FIESTA) imaging to the evaluation of cranial nerves (CN) in patients with cavernous sinus tumors. Contrast-enhanced 3D-FIESTA images were acquired from ten patients with cavernous sinus tumors with a 3-T unit. In all cases, the trigeminal nerve with tumor involvement was easily identified in the cavernous portions. Although oculomotor and abducens nerves were clearly visualized against the tumor area with intense contrast enhancement, they were hardly identifiable within the area lacking contrast enhancement. The trochlear nerve was visualized in part, but not delineated as a linear structure outside of the lesion. Contrast-enhanced 3D-FIESTA can be useful in the assessment of cranial nerves in and around the cavernous sinus with tumor involvement. (orig.)

  4. Cranial nerve assessment in cavernous sinus tumors with contrast-enhanced 3D fast-imaging employing steady-state acquisition MR imaging

    International Nuclear Information System (INIS)

    Amemiya, Shiori; Aoki, Shigeki; Ohtomo, Kuni

    2009-01-01

    The purpose of this study is to apply contrast-enhanced 3D fast-imaging employing steady-state acquisition (3D-FIESTA) imaging to the evaluation of cranial nerves (CN) in patients with cavernous sinus tumors. Contrast-enhanced 3D-FIESTA images were acquired from ten patients with cavernous sinus tumors with a 3-T unit. In all cases, the trigeminal nerve with tumor involvement was easily identified in the cavernous portions. Although oculomotor and abducens nerves were clearly visualized against the tumor area with intense contrast enhancement, they were hardly identifiable within the area lacking contrast enhancement. The trochlear nerve was visualized in part, but not delineated as a linear structure outside of the lesion. Contrast-enhanced 3D-FIESTA can be useful in the assessment of cranial nerves in and around the cavernous sinus with tumor involvement. (orig.)

  5. High Resolution 3-D Finite-Volume Coastal Ocean Modeling in Lower Campbell River and Discovery Passage, British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    Yuehua Lin

    2014-03-01

    Full Text Available The 3-D unstructured-grid, Finite-Volume Coastal Ocean Model (FVCOM was used to simulate the flows in Discovery Passage including the adjoining Lower Campbell River, British Columbia, Canada. Challenges in the studies include the strong tidal currents (e.g., up to 7.8 m/s in Seymour Narrows and tailrace discharges, small-scale topographic features and steep bottom slopes, and stratification affected by the Campbell River freshwater discharges. Two applications of high resolution 3-D FVCOM modeling were conducted. One is for the Lower Campbell River extending upstream as far as the John Hart Hydroelectric dam. The horizontal resolution varies from 0.27 m to 32 m in the unstructured triangular mesh to resolve the tailrace flow. The bottom elevation decreases ~14 m within the distance of ~1.4 km along the river. This pioneering FVCOM river modeling demonstrated a very good performance in simulating the river flow structures. The second application is to compute ocean currents immediately above the seabed along the present underwater electrical cable crossing routes across Discovery Passage. Higher resolution was used near the bottom with inter-layer spacing ranging from 0.125 to 0.0005 of total water depth. The model behaves very well in simulating the strong tidal currents in the area at high resolution in both the horizontal and vertical. One year maximum near bottom tidal current along the routes was then analyzed using the model results.

  6. Morphological image processing operators. Reduction of partial volume effects to improve 3D visualization based on CT data

    International Nuclear Information System (INIS)

    Beier, J.; Bittner, R.C.; Hosten, N.; Troeger, J.; Felix, R.

    1998-01-01

    Aim: The quality of segmentation and three-dimensional reconstruction of anatomical structures in tomographic slices is often impaired by disturbances due to partial volume effects (PVE). The potential for artefact reduction by use of the morphological image processing operators (MO) erosion and dilation is investigated. Results: For all patients under review, the artefacts caused by PVE were significantly reduced by erosion (lung: Mean SBR pre =1.67, SBR post =4.83; brain: SBR pre =1.06, SBR post =1.29) even with only a small number of iterations. Region dilation was applied to integrate further structures (e.g. at tumor borders) into a configurable neighbourhood for segmentation and quantitative analysis. Conclusions: The MO represent an efficient approach for the reduction of PVE artefacts in 3D-CT reconstructions and allow optimised visualization of individual objects. (orig./AJ) [de

  7. Interleaved 3D-CNNs for joint segmentation of small-volume structures in head and neck CT images.

    Science.gov (United States)

    Ren, Xuhua; Xiang, Lei; Nie, Dong; Shao, Yeqin; Zhang, Huan; Shen, Dinggang; Wang, Qian

    2018-02-26

    Accurate 3D image segmentation is a crucial step in radiation therapy planning of head and neck tumors. These segmentation results are currently obtained by manual outlining of tissues, which is a tedious and time-consuming procedure. Automatic segmentation provides an alternative solution, which, however, is often difficult for small tissues (i.e., chiasm and optic nerves in head and neck CT images) because of their small volumes and highly diverse appearance/shape information. In this work, we propose to interleave multiple 3D Convolutional Neural Networks (3D-CNNs) to attain automatic segmentation of small tissues in head and neck CT images. A 3D-CNN was designed to segment each structure of interest. To make full use of the image appearance information, multiscale patches are extracted to describe the center voxel under consideration and then input to the CNN architecture. Next, as neighboring tissues are often highly related in the physiological and anatomical perspectives, we interleave the CNNs designated for the individual tissues. In this way, the tentative segmentation result of a specific tissue can contribute to refine the segmentations of other neighboring tissues. Finally, as more CNNs are interleaved and cascaded, a complex network of CNNs can be derived, such that all tissues can be jointly segmented and iteratively refined. Our method was validated on a set of 48 CT images, obtained from the Medical Image Computing and Computer Assisted Intervention (MICCAI) Challenge 2015. The Dice coefficient (DC) and the 95% Hausdorff Distance (95HD) are computed to measure the accuracy of the segmentation results. The proposed method achieves higher segmentation accuracy (with the average DC: 0.58 ± 0.17 for optic chiasm, and 0.71 ± 0.08 for optic nerve; 95HD: 2.81 ± 1.56 mm for optic chiasm, and 2.23 ± 0.90 mm for optic nerve) than the MICCAI challenge winner (with the average DC: 0.38 for optic chiasm, and 0.68 for optic nerve; 95HD: 3.48 for

  8. Voluminator 2.0 - Speeding up the Approximation of the Volume of Defective 3d Building Models

    Science.gov (United States)

    Sindram, M.; Machl, T.; Steuer, H.; Pültz, M.; Kolbe, T. H.

    2016-06-01

    Semantic 3D city models are increasingly used as a data source in planning and analyzing processes of cities. They represent a virtual copy of the reality and are a common information base and source of information for examining urban questions. A significant advantage of virtual city models is that important indicators such as the volume of buildings, topological relationships between objects and other geometric as well as thematic information can be derived. Knowledge about the exact building volume is an essential base for estimating the building energy demand. In order to determine the volume of buildings with conventional algorithms and tools, the buildings may not contain any topological and geometrical errors. The reality, however, shows that city models very often contain errors such as missing surfaces, duplicated faces and misclosures. To overcome these errors (Steuer et al., 2015) have presented a robust method for approximating the volume of building models. For this purpose, a bounding box of the building is divided into a regular grid of voxels and it is determined which voxels are inside the building. The regular arrangement of the voxels leads to a high number of topological tests and prevents the application of this method using very high resolutions. In this paper we present an extension of the algorithm using an octree approach limiting the subdivision of space to regions around surfaces of the building models and to regions where, in the case of defective models, the topological tests are inconclusive. We show that the computation time can be significantly reduced, while preserving the robustness against geometrical and topological errors.

  9. 3D flow study in a mildly stenotic coronary artery phantom using a whole volume PIV method.

    Science.gov (United States)

    Brunette, J; Mongrain, R; Laurier, J; Galaz, R; Tardif, J C

    2008-11-01

    Blood flow dynamics has an important role in atherosclerosis initiation, progression, plaque rupture and thrombosis eventually causing myocardial infarction. In particular, shear stress is involved in platelet activation, endothelium function and secondary flows have been proposed as possible variables in plaque erosion. In order to investigate these three-dimensional flow characteristics in the context of a mild stenotic coronary artery, a whole volume PIV method has been developed and applied to a scaled-up transparent phantom. Experimental three-dimensional velocity data was processed to estimate the 3D shear stress distributions and secondary flows within the flow volume. The results show that shear stress reaches values out of the normal and atheroprotective range at an early stage of the obstructive pathology and that important secondary flows are also initiated at an early stage of the disease. The results also support the concept of a vena contracta associated with the jet in the context of a coronary artery stenosis with the consequence of higher shear stresses in the post-stenotic region in the blood domain than at the vascular wall.

  10. Evaluation of the relationship between renal function and renal volume-vascular indices using 3D power Doppler ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Cansu, Aysegul, E-mail: drcansu@gmail.com; Kupeli, Ali; Kul, Sibel; Eyuboglu, Ilker; Oguz, Sukru; Ozturk, Mehmet Halil; Dinc, Hasan

    2014-07-15

    Purpose: To investigate the relationship between renal function and total renal volume-vascular indices using 3D power Doppler ultrasound (3DPDUS). Materials and methods: One hundred six patients with hypertensive proteinuric nephropathy (HPN) (49 male, 57 female) and 65 healthy controls (32 male, 33 female) were evaluated prospectively using 3DPDUS. Total renal volume (RV), vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using Virtual Organ Computer-aided Analysis (VOCAL). The estimated glomerular filtration rates (GFRs) of the patients with HPN and the control group were calculated. The patients with HPN were divided into two groups on the basis of GFR, normal (≥90) or reduced (<90). Differences between groups were compared using ANOVA. Correlations between GFR, renal volume and vascular indices were analyzed using Pearson's correlation analysis. Significance was set at p < 0.05. Results: The mean total RV, VI, FI and VFI values in the reduced GFR, normal GFR and control groups were RV (ml): 234.7, 280.7 and 294.6; VI: 17.6, 27.6 and 46.8; FI: 79.1, 88.7 and 93.9 and VFI: 7.1, 12.7 and 23.8. There were statistically significant differences between the groups (p < 0.001). Total RVs and vascular indices exhibited significant correlations with estimated GFR (r = 0.53–0.59, p < 0.001) Conclusion: Three-dimensional power Doppler ultrasound is a reliable predictive technique in renal function analysis.

  11. 3D organic Na4C6O6/graphene architecture for fast sodium storage with ultralong cycle life.

    Science.gov (United States)

    Gu, Jianan; Gu, Yue; Yang, Shubin

    2017-11-23

    Sodium-ion batteries (SIBs) have aroused increasing interest as one of the most promising replacements for lithium-ion batteries (LIBs). Here, a novel organic-inorganic 3D Na 4 C 6 O 6 -graphene architecture was successfully fabricated from commercial Na 2 C 6 O 6 and for the first time applied for sodium storage. Hence, the 3D Na 4 C 6 O 6 -graphene architecture exhibits a high reversible capacity, good cyclic performance and high-rate capability for sodium storage.

  12. Recommendations from gynaecological (GYN) GEC ESTRO working group (II): Concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy-3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, radiobiology

    International Nuclear Information System (INIS)

    Poetter, Richard; Haie-Meder, Christine; Limbergen, Erik van; Barillot, Isabelle; Brabandere, Marisol De; Dimopoulos, Johannes; Dumas, Isabelle; Erickson, Beth; Lang, Stefan; Nulens, An; Petrow, Peter; Rownd, Jason; Kirisits, Christian

    2006-01-01

    The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm 3 ; optional 5 and 10 cm 3 . Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm 3 . Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD 2 )-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Poetter R, Van Limbergen E et al

  13. Prostate and seminal vesicle volume based consideration of prostate cancer patients for treatment with 3D-conformal or intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Reddy, Nandanuri M. S.; Nori, Dattatreyudu; Chang, Hyesook; Lange, Christopher S.; Ravi, Akkamma

    2010-01-01

    Purpose: The purpose of this article was to determine the suitability of the prostate and seminal vesicle volumes as factors to consider patients for treatment with image-guided 3D-conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT), using common dosimetry parameters as comparison tools. Methods: Dosimetry of 3D and IMRT plans for 48 patients was compared. Volumes of prostate, SV, rectum, and bladder, and prescriptions were the same for both plans. For both 3D and IMRT plans, expansion margins to prostate+SV (CTV) and prostate were 0.5 cm posterior and superior and 1 cm in other dimensions to create PTV and CDPTV, respectively. Six-field 3D plans were prepared retrospectively. For 3D plans, an additional 0.5 cm margin was added to PTV and CDPTV. Prescription for both 3D and IMRT plans was the same: 45 Gy to CTV followed by a 36 Gy boost to prostate. Dosimetry parameters common to 3D and IMRT plans were used for comparison: Mean doses to prostate, CDPTV, SV, rectum, bladder, and femurs; percent volume of rectum and bladder receiving 30 (V30), 50 (V50), and 70 Gy (V70), dose to 30% of rectum and bladder, minimum and maximum point dose to CDPTV, and prescription dose covering 95% of CDPTV (D95). Results: When the data for all patients were combined, mean dose to prostate and CDPTV was higher with 3D than IMRT plans (P 0.2). On average, among all cases, the minimum point dose was less for 3D-CRT plans and the maximum point dose was greater for 3D-CRT than for IMRT (P 0.1). V30 was less (P 0.2), and V70 was more (P 0.2). Mean dose to femurs was more with 3D than IMRT plans (P 3 (39/48), respectively (P 3 , respectively, would be suitable for 3D-CRT. Patients with prostate and prostate+SV volumes >65 and 85 cm 3 , respectively, might get benefit from IMRT.

  14. Fast computation of hologram patterns of a 3D object using run-length encoding and novel look-up table methods.

    Science.gov (United States)

    Kim, Seung-Cheol; Kim, Eun-Soo

    2009-02-20

    In this paper we propose a new approach for fast generation of computer-generated holograms (CGHs) of a 3D object by using the run-length encoding (RLE) and the novel look-up table (N-LUT) methods. With the RLE method, spatially redundant data of a 3D object are extracted and regrouped into the N-point redundancy map according to the number of the adjacent object points having the same 3D value. Based on this redundancy map, N-point principle fringe patterns (PFPs) are newly calculated by using the 1-point PFP of the N-LUT, and the CGH pattern for the 3D object is generated with these N-point PFPs. In this approach, object points to be involved in calculation of the CGH pattern can be dramatically reduced and, as a result, an increase of computational speed can be obtained. Some experiments with a test 3D object are carried out and the results are compared to those of the conventional methods.

  15. Comparison of rectal volume definition techniques and their influence on rectal toxicity in patients with prostate cancer treated with 3D conformal radiotherapy: a dose-volume analysis

    International Nuclear Information System (INIS)

    Onal, Cem; Topkan, Erkan; Efe, Esma; Yavuz, Melek; Sonmez, Serhat; Yavuz, Aydin

    2009-01-01

    To evaluate the impact of four different rectum contouring techniques and rectal toxicities in patients with treated with 3D conformal radiotherapy (3DCRT). Clinical and dosimetric data were evaluated for 94 patients who received a total dose 3DCRT of 70 Gy, and rectal doses were compared in four different rectal contouring techniques: the prostate-containing CT sections (method 1); 1 cm above and below the planning target volume (PTV) (method 2); 110 mm starting from the anal verge (method 3); and from the anal verge to the sigmoid flexure (method 4). The percentage of rectal volume receiving RT doses (30–70 Gy) and minimum, mean rectal doses were assessed. Median age was 69 years. Percentage of rectal volume receiving high doses (≥ 70 Gy) were higher with the techniques that contoured smaller rectal volumes. In methods 2 and 3, the percentage of rectal volume receiving ≥ 70 Gy was significantly higher in patients with than without rectal bleeding (method 2: 30.8% vs. 22.5%, respectively (p = 0.03); method 3: 26.9% vs. 18.1%, respectively (p = 0.006)). Mean rectal dose was significant predictor of rectal bleeding only in method 3 (48.8 Gy in patients with bleeding vs. 44.4 Gy in patients without bleeding; p = 0.02). Different techniques of rectal contouring significantly influence the calculation of radiation doses to the rectum and the prediction of rectal toxicity. Rectal volume receiving higher doses (≥ 70 Gy) and mean rectal doses may significantly predict rectal bleeding for techniques contouring larger rectal volumes, as was in method 3

  16. Fast reconstruction of 3D time-of-flight PET data by axial rebinning and transverse mashing

    International Nuclear Information System (INIS)

    Vandenberghe, Stefaan; Daube-Witherspoon, Margaret E; Lewitt, Robert M; Karp, Joel S

    2006-01-01

    Faster scintillators like LaBr 3 and LSO have sparked renewed interest in PET scanners with time-of-flight (TOF) information. The TOF information adds another dimension to the data set compared to conventional three-dimensional (3D) PET with the size of the projection data being multiplied by the number of TOF bins. Here we show by simulations and analytical reconstruction that angular sampling for two-dimensional (2D) TOF PET can be reduced significantly compared to what is required for conventional 2D PET. Fully 3D TOF PET data, however, have a wide range of oblique and transverse angles. To make use of the smaller necessary angular sampling we reduce the 3D data to a set of 2D histoprojections. This is done by rebinning the 3D data to 2D data and by mashing these 2D data into a limited number of angles. Both methods are based on the most likely point given by the TOF measurement. It is shown that the axial resolution loss associated with rebinning reduces with improved timing resolution and becomes less than 1 mm for a TOF resolution below 300 ps. The amount of angular mashing that can be applied without tangential resolution loss increases with improved TOF resolution. Even quite coarse angular mashing (18 angles out of 324 measured angles for 424 ps) does not significantly reduce image quality in terms of the contrast or noise. The advantages of the proposed methods are threefold. Data storage is reduced to a limited number of 2D histoprojections with TOF information. Compared to listmode format we have the advantage of a predetermined storage space and faster reconstruction. The method does not require the normalization of projections prior to rebinning and can be applied directly to measured listmode data

  17. Mechanical behavior of a fast reactor core application of 3D codes to SUPER-PHENIX 1 and parametric studies

    International Nuclear Information System (INIS)

    Bernard, A.; Dorsselaere, J.P. van

    1984-01-01

    This paper presents the SPX1 project calculations, performed on 1/3 core with the aid of the series of 3D codes described in Session 2. The main criteria, related to contact forces, head bowings and handling forces, are fulfilled. Some parametric studies on the mechanical equilibrium are also presented. The main parameters are: the axial pad level, the subassembly stiffness and the pad local stiffness. (author)

  18. The 3D thermal-hydraulic numerical simulation for the fuel zone outlet of China experimental fast reactor

    International Nuclear Information System (INIS)

    Xue Xiuli; Yang Hongyi; Yang Fuchang

    2008-01-01

    Detailed 3D thermal-hydraulic numerical analyses to the fuel zone outlet are actualized with the STAR-CD CFD code. The performance of sodium mixing is studied and detailed velocity and temperature distribution are obtained in this region which will offer foundations and references to study the rationality of temperature monitoring-spot arrangement and to assess the effect of temperature fluctuations to control rod guide tubes in this region, and so on. (authors)

  19. A numerical study of super-resolution through fast 3D wideband algorithm for scattering in highly-heterogeneous media

    KAUST Repository

    Lé tourneau, Pierre-David; Wu, Ying; Papanicolaou, George; Garnier, Josselin; Darve, Eric

    2016-01-01

    We present a wideband fast algorithm capable of accurately computing the full numerical solution of the problem of acoustic scattering of waves by multiple finite-sized bodies such as spherical scatterers in three dimensions. By full solution, we

  20. Single minimum incision endoscopic radical nephrectomy for renal tumors with preoperative virtual navigation using 3D-CT volume-rendering

    Directory of Open Access Journals (Sweden)

    Shioyama Yasukazu

    2010-04-01

    Full Text Available Abstract Background Single minimum incision endoscopic surgery (MIES involves the use of a flexible high-definition laparoscope to facilitate open surgery. We reviewed our method of radical nephrectomy for renal tumors, which is single MIES combined with preoperative virtual surgery employing three-dimensional CT images reconstructed by the volume rendering method (3D-CT images in order to safely and appropriately approach the renal hilar vessels. We also assessed the usefulness of 3D-CT images. Methods Radical nephrectomy was done by single MIES via the translumbar approach in 80 consecutive patients. We performed the initial 20 MIES nephrectomies without preoperative 3D-CT images and the subsequent 60 MIES nephrectomies with preoperative 3D-CT images for evaluation of the renal hilar vessels and the relation of each tumor to the surrounding structures. On the basis of the 3D information, preoperative virtual surgery was performed with a computer. Results Single MIES nephrectomy was successful in all patients. In the 60 patients who underwent 3D-CT, the number of renal arteries and veins corresponded exactly with the preoperative 3D-CT data (100% sensitivity and 100% specificity. These 60 nephrectomies were completed with a shorter operating time and smaller blood loss than the initial 20 nephrectomies. Conclusions Single MIES radical nephrectomy combined with 3D-CT and virtual surgery achieved a shorter operating time and less blood loss, possibly due to safer and easier handling of the renal hilar vessels.

  1. Geographic miss of lung tumours due to respiratory motion: a comparison of 3D vs 4D PET/CT defined target volumes

    International Nuclear Information System (INIS)

    Callahan, Jason; Kron, Tomas; Siva, Shankar; Simoens, Nathalie; Edgar, Amanda; Everitt, Sarah; Schneider, Michal E; Hicks, Rodney J

    2014-01-01

    PET/CT scans acquired in the radiotherapy treatment position are typically performed without compensating for respiratory motion. The purpose of this study was to investigate geographic miss of lung tumours due to respiratory motion for target volumes defined on a standard 3D-PET/CT. 29 patients staged for pulmonary malignancy who completed both a 3D-PET/CT and 4D-PET/CT were included. A 3D-Gross Tumour Volume (GTV) was defined on the standard whole body PET/CT scan. Subsequently a 4D-GTV was defined on a 4D-PET/CT MIP. A 5 mm, 10 mm, 15 mm symmetrical and 15×10 mm asymmetrical Planning Target Volume (PTV) was created by expanding the 3D-GTV and 4D-GTV’s. A 3D conformal plan was generated and calculated to cover the 3D-PTV. The 3D plan was transferred to the 4D-PTV and analysed for geographic miss. Three types of miss were measured. Type 1: any part of the 4D-GTV outside the 3D-PTV. Type 2: any part of the 4D-PTV outside the 3D-PTV. Type 3: any part of the 4D-PTV receiving less than 95% of the prescribed dose. The lesion motion was measured to look at the association between lesion motion and geographic miss. When a standard 15 mm or asymmetrical PTV margin was used there were 1/29 (3%) Type 1 misses. This increased 7/29 (24%) for the 10 mm margin and 23/29 (79%) for a 5 mm margin. All patients for all margins had a Type 2 geographic miss. There was a Type 3 miss in 25 out of 29 cases in the 5, 10, and 15 mm PTV margin groups. The asymmetrical margin had one additional Type 3 miss. Pearson analysis showed a correlation (p < 0.01) between lesion motion and the severity of the different types of geographic miss. Without any form of motion suppression, the current standard of a 3D- PET/CT and 15 mm PTV margin employed for lung lesions has an increasing risk of significant geographic miss when tumour motion increases. Use of smaller asymmetric margins in the cranio-caudal direction does not comprise tumour coverage. Reducing PTV margins for volumes defined on 3D

  2. Fast multi-core based multimodal registration of 2D cross-sections and 3D datasets

    Directory of Open Access Journals (Sweden)

    Pielot Rainer

    2010-01-01

    Full Text Available Abstract Background Solving bioinformatics tasks often requires extensive computational power. Recent trends in processor architecture combine multiple cores into a single chip to improve overall performance. The Cell Broadband Engine (CBE, a heterogeneous multi-core processor, provides power-efficient and cost-effective high-performance computing. One application area is image analysis and visualisation, in particular registration of 2D cross-sections into 3D image datasets. Such techniques can be used to put different image modalities into spatial correspondence, for example, 2D images of histological cuts into morphological 3D frameworks. Results We evaluate the CBE-driven PlayStation 3 as a high performance, cost-effective computing platform by adapting a multimodal alignment procedure to several characteristic hardware properties. The optimisations are based on partitioning, vectorisation, branch reducing and loop unrolling techniques with special attention to 32-bit multiplies and limited local storage on the computing units. We show how a typical image analysis and visualisation problem, the multimodal registration of 2D cross-sections and 3D datasets, benefits from the multi-core based implementation of the alignment algorithm. We discuss several CBE-based optimisation methods and compare our results to standard solutions. More information and the source code are available from http://cbe.ipk-gatersleben.de. Conclusions The results demonstrate that the CBE processor in a PlayStation 3 accelerates computational intensive multimodal registration, which is of great importance in biological/medical image processing. The PlayStation 3 as a low cost CBE-based platform offers an efficient option to conventional hardware to solve computational problems in image processing and bioinformatics.

  3. Fast multi-core based multimodal registration of 2D cross-sections and 3D datasets.

    Science.gov (United States)

    Scharfe, Michael; Pielot, Rainer; Schreiber, Falk

    2010-01-11

    Solving bioinformatics tasks often requires extensive computational power. Recent trends in processor architecture combine multiple cores into a single chip to improve overall performance. The Cell Broadband Engine (CBE), a heterogeneous multi-core processor, provides power-efficient and cost-effective high-performance computing. One application area is image analysis and visualisation, in particular registration of 2D cross-sections into 3D image datasets. Such techniques can be used to put different image modalities into spatial correspondence, for example, 2D images of histological cuts into morphological 3D frameworks. We evaluate the CBE-driven PlayStation 3 as a high performance, cost-effective computing platform by adapting a multimodal alignment procedure to several characteristic hardware properties. The optimisations are based on partitioning, vectorisation, branch reducing and loop unrolling techniques with special attention to 32-bit multiplies and limited local storage on the computing units. We show how a typical image analysis and visualisation problem, the multimodal registration of 2D cross-sections and 3D datasets, benefits from the multi-core based implementation of the alignment algorithm. We discuss several CBE-based optimisation methods and compare our results to standard solutions. More information and the source code are available from http://cbe.ipk-gatersleben.de. The results demonstrate that the CBE processor in a PlayStation 3 accelerates computational intensive multimodal registration, which is of great importance in biological/medical image processing. The PlayStation 3 as a low cost CBE-based platform offers an efficient option to conventional hardware to solve computational problems in image processing and bioinformatics.

  4. Fast, free-breathing, in vivo fetal imaging using time-resolved 3D MRI technique: preliminary results

    OpenAIRE

    Liu, Jing; Glenn, Orit A.; Xu, Duan

    2014-01-01

    Fetal MR imaging is very challenging due to the movement of fetus and the breathing motion of the mother. Current clinical protocols involve quick 2D scouting scans to determine scan plane and often several attempts to reorient the scan plane when the fetus moves. This makes acquisition of fetal MR images clinically challenging and results in long scan times in order to obtain images that are of diagnostic quality. Compared to 2D imaging, 3D imaging of the fetus has many advantages such as hi...

  5. High-resolution T2-weighted MR imaging of the inner ear using a long echo-train-length 3D fast spin-echo sequence

    International Nuclear Information System (INIS)

    Naganawa, S.; Yamakawa, K.; Fukatsu, H.; Ishigaki, T.; Nakashima, T.; Sugimoto, H.; Aoki, I.; Miyazaki, M.; Takai, H.

    1996-01-01

    The purpose of this study was to assess the value of a long echo-train-length 3D fast spin-echo (3D-FSE) sequence in visualizing the inner ear structures. Ten normal ears and 50 patient ears were imaged on a 1.5T MR unit using a head coil. Axial high-resolution T2-weighted images of the inner ear and the internal auditory canal (IAC) were obtained in 15 min. In normal ears the reliability of the visualization for the inner ear structures was evaluated on original images and the targeted maximum intensity projection (MIP) images of the labyrinth. In ten normal ears, 3D surface display (3D) images were also created and compared with MIP images. On the original images the cochlear aqueduct, the vessels in the vicinity of the IAC, and more than three branches of the cranial nerves were visualized in the IAC in all the ears. The visibility of the endolympathic duct was 80%. On the MIP images the visibility of the three semicircular canals, anterior and posterior ampulla, and of more than two turns of the cochlea was 100%. The MIP images and 3D images were almost comparable. The visibility of the endolymphatic duct was 80% in normal ears and 0% in the affected ears of the patients with Meniere's disease (p<0.001). In one patient ear a small intracanalicular tumor was depicted clearly. In conclusion, the long echo train length T2-weighted 3D-FSE sequence enables the detailed visualization of the tiny structures of the inner ear and the IAC within a clinically acceptable scan time. Furthermore, obtaining a high contrast between the soft/bony tissue and the cerebrospinal/endolymph/perilymph fluid would be of significant value in the diagnosis of the pathologic conditions around the labyrinth and the IAC. (orig.)

  6. Accuracy and reliability of noninvasive stroke volume monitoring via ECG-gated 3D electrical impedance tomography in healthy volunteers

    Science.gov (United States)

    Proença, Martin; Adler, Andy; Riedel, Thomas; Thiran, Jean-Philippe; Solà, Josep

    2018-01-01

    Cardiac output (CO) and stroke volume (SV) are parameters of key clinical interest. Many techniques exist to measure CO and SV, but are either invasive or insufficiently accurate in clinical settings. Electrical impedance tomography (EIT) has been suggested as a noninvasive measure of SV, but inconsistent results have been reported. Our goal is to determine the accuracy and reliability of EIT-based SV measurements, and whether advanced image reconstruction approaches can help to improve the estimates. Data were collected on ten healthy volunteers undergoing postural changes and exercise. To overcome the sensitivity to heart displacement and thorax morphology reported in previous work, we used a 3D EIT configuration with 2 planes of 16 electrodes and subject-specific reconstruction models. Various EIT-derived SV estimates were compared to reference measurements derived from the oxygen uptake. Results revealed a dramatic impact of posture on the EIT images. Therefore, the analysis was restricted to measurements in supine position under controlled conditions (low noise and stable heart and lung regions). In these measurements, amplitudes of impedance changes in the heart and lung regions could successfully be derived from EIT using ECG gating. However, despite a subject-specific calibration the heart-related estimates showed an error of 0.0 ± 15.2 mL for absolute SV estimation. For trending of relative SV changes, a concordance rate of 80.9% and an angular error of −1.0 ± 23.0° were obtained. These performances are insufficient for most clinical uses. Similar conclusions were derived from lung-related estimates. Our findings indicate that the key difficulty in EIT-based SV monitoring is that purely amplitude-based features are strongly influenced by other factors (such as posture, electrode contact impedance and lung or heart conductivity). All the data of the present study are made publicly available for further investigations. PMID:29373611

  7. DKE: a fast numerical solver for the 3-D relativistic bounce-averaged electron drift kinetic equation

    Energy Technology Data Exchange (ETDEWEB)

    Decker, J.; Peysson, Y

    2004-12-01

    A new original code for solving the 3-D relativistic and bounce-averaged electron drift kinetic equation is presented. It designed for the current drive problem in tokamak with an arbitrary magnetic equilibrium. This tool allows self-consistent calculations of the bootstrap current in presence of other external current sources. RF current drive for arbitrary type of waves may be used. Several moments of the electron distribution function are determined, like the exact and effective fractions of trapped electrons, the plasma current, absorbed RF power, runaway and magnetic ripple loss rates and non-thermal Bremsstrahlung. Advanced numerical techniques have been used to make it the first fully implicit (reverse time) 3-D solver, particularly well designed for implementation in a chain of code for realistic current drive calculations in high {beta}{sub p} plasmas. All the details of the physics background and the numerical scheme are presented, as well a some examples to illustrate main code capabilities. Several important numerical points are addressed concerning code stability and potential numerical and physical limitations. (authors)

  8. A novel structured dictionary for fast processing of 3D medical images, with application to computed tomography restoration and denoising

    Science.gov (United States)

    Karimi, Davood; Ward, Rabab K.

    2016-03-01

    Sparse representation of signals in learned overcomplete dictionaries has proven to be a powerful tool with applications in denoising, restoration, compression, reconstruction, and more. Recent research has shown that learned overcomplete dictionaries can lead to better results than analytical dictionaries such as wavelets in almost all image processing applications. However, a major disadvantage of these dictionaries is that their learning and usage is very computationally intensive. In particular, finding the sparse representation of a signal in these dictionaries requires solving an optimization problem that leads to very long computational times, especially in 3D image processing. Moreover, the sparse representation found by greedy algorithms is usually sub-optimal. In this paper, we propose a novel two-level dictionary structure that improves the performance and the speed of standard greedy sparse coding methods. The first (i.e., the top) level in our dictionary is a fixed orthonormal basis, whereas the second level includes the atoms that are learned from the training data. We explain how such a dictionary can be learned from the training data and how the sparse representation of a new signal in this dictionary can be computed. As an application, we use the proposed dictionary structure for removing the noise and artifacts in 3D computed tomography (CT) images. Our experiments with real CT images show that the proposed method achieves results that are comparable with standard dictionary-based methods while substantially reducing the computational time.

  9. Fast and accurate global multiphase arrival tracking: the irregular shortest-path method in a 3-D spherical earth model

    Science.gov (United States)

    Huang, Guo-Jiao; Bai, Chao-Ying; Greenhalgh, Stewart

    2013-09-01

    The traditional grid/cell-based wavefront expansion algorithms, such as the shortest path algorithm, can only find the first arrivals or multiply reflected (or mode converted) waves transmitted from subsurface interfaces, but cannot calculate the other later reflections/conversions having a minimax time path. In order to overcome the above limitations, we introduce the concept of a stationary minimax time path of Fermat's Principle into the multistage irregular shortest path method. Here we extend it from Cartesian coordinates for a flat earth model to global ray tracing of multiple phases in a 3-D complex spherical earth model. The ray tracing results for 49 different kinds of crustal, mantle and core phases show that the maximum absolute traveltime error is less than 0.12 s and the average absolute traveltime error is within 0.09 s when compared with the AK135 theoretical traveltime tables for a 1-D reference model. Numerical tests in terms of computational accuracy and CPU time consumption indicate that the new scheme is an accurate, efficient and a practical way to perform 3-D multiphase arrival tracking in regional or global traveltime tomography.

  10. DKE: a fast numerical solver for the 3-D relativistic bounce-averaged electron drift kinetic equation

    International Nuclear Information System (INIS)

    Decker, J.; Peysson, Y.

    2004-12-01

    A new original code for solving the 3-D relativistic and bounce-averaged electron drift kinetic equation is presented. It designed for the current drive problem in tokamak with an arbitrary magnetic equilibrium. This tool allows self-consistent calculations of the bootstrap current in presence of other external current sources. RF current drive for arbitrary type of waves may be used. Several moments of the electron distribution function are determined, like the exact and effective fractions of trapped electrons, the plasma current, absorbed RF power, runaway and magnetic ripple loss rates and non-thermal Bremsstrahlung. Advanced numerical techniques have been used to make it the first fully implicit (reverse time) 3-D solver, particularly well designed for implementation in a chain of code for realistic current drive calculations in high β p plasmas. All the details of the physics background and the numerical scheme are presented, as well a some examples to illustrate main code capabilities. Several important numerical points are addressed concerning code stability and potential numerical and physical limitations. (authors)

  11. Analysis of thorium and uranium fuel cycles in an iso-breeder lead fast reactor using extended-EQL3D procedure

    International Nuclear Information System (INIS)

    Fiorina, Carlo; Krepel, Jiri; Cammi, Antonio; Franceschini, Fausto; Mikityuk, Konstantin; Ricotti, Marco Enrico

    2013-01-01

    Highlights: ► Extension of EQL3D procedure to calculate radio-toxicity and decay heat. ► Characterization of uranium- and thorium-fueled LFR from BOL to equilibrium. ► Safety improvements for a LFR in a closed thorium cycle. ► Advantages of thorium-fueled LFR in terms of decay heat and radio-toxicity generation. ► Safety, decay heat and radio-toxicity concerns for a Th–Pu beginning-of-life core. - Abstract: Use of thorium in fast reactors has typically been considered as a secondary option, mainly thanks to a possible self-sustaining thorium cycle already in thermal reactors and due to the limited breeding capabilities compared to U–Pu in the fast neutron energy range. In recent years nuclear waste management has become more important, and the thorium option has been reconsidered for the claimed potential to burn transuranic waste and the lower build-up of hazardous isotopes in a closed cycle. To ascertain these claims and their limitations, the fuel cycle isotopic inventory, and associated waste radio-toxicity and decay heat, should be quantified and compared to the case of the uranium cycle using realistic core configurations, with complete recycle of all the actinides. Since the transition from uranium to thorium fuel cycles will likely involve a transuranic burning phase, this transition and the challenges that the evolving fuel actinide composition presents, for instance on reactor feedback parameters, should also be analyzed. In the present paper, these issues are investigated based on core physics analysis of the Lead-cooled Fast Reactor ELSY, performed with the fast reactor ERANOS code and the EQL3D procedure allowing full-core characterization of the equilibrium cycle and the transition cycles. In order to compute radio-toxicity and decay heat, EQL3D has been extended by developing a new module, which has been assessed against ORIGEN-S and is presented here. The capability of the EQL3D procedure to treat full-core 3D geometries allowed to

  12. Fast Simulation of 3-D Surface Flanging and Prediction of the Flanging Lines Based On One-Step Inverse Forming Algorithm

    International Nuclear Information System (INIS)

    Bao Yidong; Hu Sibo; Lang Zhikui; Hu Ping

    2005-01-01

    A fast simulation scheme for 3D curved binder flanging and blank shape prediction of sheet metal based on one-step inverse finite element method is proposed, in which the total plasticity theory and proportional loading assumption are used. The scheme can be actually used to simulate 3D flanging with complex curve binder shape, and suitable for simulating any type of flanging model by numerically determining the flanging height and flanging lines. Compared with other methods such as analytic algorithm and blank sheet-cut return method, the prominent advantage of the present scheme is that it can directly predict the location of the 3D flanging lines when simulating the flanging process. Therefore, the prediction time of flanging lines will be obviously decreased. Two typical 3D curve binder flanging including stretch and shrink characters are simulated in the same time by using the present scheme and incremental FE non-inverse algorithm based on incremental plasticity theory, which show the validity and high efficiency of the present scheme

  13. Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water.

    Science.gov (United States)

    Glaser, Adam K; Andreozzi, Jacqueline M; Zhang, Rongxiao; Pogue, Brian W; Gladstone, David J

    2015-07-01

    To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp-Davis-Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm(3) volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%-99% pass fraction depending on the chosen threshold dose. The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.

  14. Fast selective trapping and release of picoliter droplets in a 3D microfluidic PDMS multi-trap system with bubbles.

    Science.gov (United States)

    Rambach, Richard W; Biswas, Preetika; Yadav, Ashutosh; Garstecki, Piotr; Franke, Thomas

    2018-02-12

    The selective manipulation and incubation of individual picoliter drops in high-throughput droplet based microfluidic devices still remains challenging. We used a surface acoustic wave (SAW) to induce a bubble in a 3D designed multi-trap polydimethylsiloxane (PDMS) device to manipulate multiple droplets and demonstrate the selection, incubation and on-demand release of aqueous droplets from a continuous oil flow. By controlling the position of the acoustic actuation, individual droplets are addressed and selectively released from a droplet stream of 460 drops per s. A complete trapping and releasing cycle can be as short as 70 ms and has no upper limit for incubation time. We characterize the fluidic function of the hybrid device in terms of electric power, pulse duration and acoustic path.

  15. Comparison of 3D vs. 2D fast spin echo imaging for evaluation of articular cartilage in the knee on a 3 T system scientific research

    International Nuclear Information System (INIS)

    Milewski, Matthew D.; Smitaman, Edward; Moukaddam, Hicham; Katz, Lee D.; Essig, David A.; Medvecky, Michael J.; Haims, Andrew H.

    2012-01-01

    Highlights: ► Compared 3D to 2D MR sequences for articular cartilage in the knee. ► 3D imaging acquired in a single plane, 2D acquired in 3 separate planes. ► No significant difference in accuracy between 3D and 2D sequences. - Abstract: Purpose: We sought to retrospectively compare the accuracy of a three-dimensional fat-suppressed, fast spin-echo sequences acquired in the sagittal plane, with multiplanar reconstructions to that of two-dimensional fat-suppressed, fast spin echo sequences acquired in three planes on a 3 T MR system for the evaluation of articular cartilage in the knee. Materials and methods: Our study group consisted of all patients (N = 34) that underwent 3 T MR imaging of the knee at our institution with subsequent arthroscopy over an 18-month period. There were 21 males and 13 females with an average age of 36 years. MR images were reviewed by 3 musculoskeletal radiologists, blinded to operative results. 3D and 2D sequences were reviewed at different sittings separated by 4 weeks to prevent bias. Six cartilage surfaces were evaluated both with MR imaging and arthroscopically with a modified Noyes scoring system and arthroscopic results were used as the gold standard. Sensitivity, specificity, and accuracy were calculated for each reader along with Fleiss Kappa assessment agreement between the readers. Accuracies for each articular surface were compared using a difference in proportions test with a 95% confidence interval and statistical significance was calculated using a Fisher's Exact Test. Results: Two hundred and four articular surfaces were evaluated and 49 articular cartilage lesions were present at arthroscopy. For the patellofemoral surfaces, the sensitivity, specificity, and accuracy were 76.5%, 83%, and 78.2% for the 3D sequences and were 82.3%, 76%, and 82% respectively for the 2D sequences. For the medial compartment surfaces, the sensitivity, specificity, and accuracy were 81.1%, 65.1%, and 78.5% for the 3D sequences and were

  16. A numerical study of super-resolution through fast 3D wideband algorithm for scattering in highly-heterogeneous media

    KAUST Repository

    Létourneau, Pierre-David

    2016-09-19

    We present a wideband fast algorithm capable of accurately computing the full numerical solution of the problem of acoustic scattering of waves by multiple finite-sized bodies such as spherical scatterers in three dimensions. By full solution, we mean that no assumption (e.g. Rayleigh scattering, geometrical optics, weak scattering, Born single scattering, etc.) is necessary regarding the properties of the scatterers, their distribution or the background medium. The algorithm is also fast in the sense that it scales linearly with the number of unknowns. We use this algorithm to study the phenomenon of super-resolution in time-reversal refocusing in highly-scattering media recently observed experimentally (Lemoult et al., 2011), and provide numerical arguments towards the fact that such a phenomenon can be explained through a homogenization theory.

  17. Evaluation of dose coverage to target volume and normal tissue sparing in the adjuvant radiotherapy of gastric cancers: 3D-CRT compared with dynamic IMRT.

    Science.gov (United States)

    Murthy, Kk; Shukeili, Ka; Kumar, Ss; Davis, Ca; Chandran, Rr; Namrata, S

    2010-01-01

    To assess the potential advantage of intensity-modulated radiotherapy (IMRT) over 3D-conformal radiotherapy (3D-CRT) planning in postoperative adjuvant radiotherapy for patients with gastric carcinoma. In a retrospective study, for plan comparison, dose distribution was recalculated in 15 patients treated with 3D-CRT on the contoured structures of same CT images using an IMRT technique. 3D-conformal plans with three fields and four-fields were compared with seven-field dynamic IMRT plans. The different plans were compared by analyzing the dose coverage of planning target volume using TV(95), D(mean), uniformity index, conformity index and homogeneity index parameters. To assess critical organ sparing, D(mean), D(max), dose to one-third and two-third volumes of the OARs and percentage of volumes receiving more than their tolerance doses were compared. The average dose coverage values of PTV with 3F-CRT and 4F-CRT plans were comparable, where as IMRT plans achieved better target coverage(p3D-CRT plans. The doses to the liver and bowel reduced significantly (p3D-CRT plans. For all OARs the percentage of volumes receiving more than their tolerance doses were reduced with the IMRT plans. This study showed that a better target coverage and significant dose reduction to OARs could be achieved with the IMRT plans. The IMRT can be preferred with caution for organ motion. The authors are currently studying organ motion in the upper abdomen to use IMRT for patient treatment.

  18. Comparison of dose-volume histograms for Tomo therapy, linear accelerator-based 3D conformal radiation therapy, and intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Choi, Seong-Kwan; Chung, Woon-Kwan; Lee, Jong-Woong

    2011-01-01

    Highlights: → Evaluation of DVH from 3D CRT, IMRT and Tomo therapy was conducted for tumor therapy. → The doses of GTV and CTV were compared using DVHs from 3D CRT, IMRT and Tomo therapy. → The GTV was higher when Tomo therapy was used, while the doses of critical organ were low. → They said that Tomo therapy satisfied the goal of radiation therapy more than the others. - Abstract: Evaluation of dose-volume histograms from three-dimensional conformal radiation therapy (3D CRT), intensity-modulated radiation therapy (IMRT), and Tomo therapy was conducted. These three modalities are among the diverse treatment systems available for tumor therapy. Three patients who received tumor therapy for a malignant oligodendroglioma in the cranium, nasopharyngeal carcinoma in the cervical neck, and prostate cancer in the pelvis were selected as study subjects. Therapy plans were made for the three patients before dose-volume histograms were obtained. The doses of the gross tumor volume (GTV) and the clinical target volume (CTV) were compared using the dose-volume histograms obtained from the LINAC-based 3D CRT, IMRT planning station (Varian Eclipse-Varian, version 8.1), and Tomo therapy planning station. In addition, the doses of critical organs in the cranium, cervix, and pelvis that should be protected were compared. The GTV was higher when Tomo therapy was used compared to 3D CRT and the LINAC-based IMRT, while the doses of critical organ tissues that required protection were low. These results demonstrated that Tomo therapy satisfied the ultimate goal of radiation therapy more than the other therapies.

  19. A dosimetry system for fast measurement of 3D depth-dose profiles in charged-particle tumor therapy with scanning techniques

    International Nuclear Information System (INIS)

    Brusasco, C.; Voss, B.; Schardt, D.; Kraemer, M.; Kraft, G.

    2000-01-01

    The high complexity and high instantaneous dose rates of the intensity modulated treatment plans performed using carbon beams at GSI require a good granularity of the dose verification procedures. As a consequence, a new detector system was developed in order to obtain a 3D reconstruction of the relative depth-dose distributions in a short time, with high granularity and over large volumes. The system takes advantage of the active beam delivery system operative in the therapy facility of GSI and consists of one position sensitive detector with a stack of ionization chambers and a range-shifter. After a technical description of the apparatus, the procedure to reconstruct the 3D measurements is explained and the possible sources of errors in the measurements are analyzed. Finally, the results of the measurement of some treatment plans are shown

  20. A capacitive DAC with custom 3-D 1-fF MOM unit capacitors optimized for fast-settling routing in high speed SAR ADCs

    International Nuclear Information System (INIS)

    Chen Chixiao; Xiang Jixuan; Chen Huabin; Xu Jun; Ye Fan; Li Ning; Ren Junyan

    2015-01-01

    Asynchronous successive approximation register (SAR) analog-to-digital converters (ADC) feature high energy efficiency but medium performance. From the point of view of speed, the key bottleneck is the unit capacitor size. In this paper, a small size three-dimensional (3-D) metal—oxide—metal (MOM) capacitor is proposed. The unit capacitor has a capacitance of 1-fF. It shapes as an umbrella, which is designed for fast settling consideration. A comparison among the proposed capacitor with other 3-D MOM capacitors is also given in the paper. To demonstrate the effectiveness of the MOM capacitor, a 6-b capacitive DAC is implemented in TSMC 1P9M 65 nm LP CMOS technology. The DAC consumes a power dissipation of 0.16 mW at the rate of 100 MS/s, excluding a source-follower based output buffer. Static measurement result shows that INL is less than ±1 LSB and DNL is less than ±0.5 LSB. In addition, a 100 MS/s 9-bit SAR ADC with the proposed 3-D capacitor is simulated. (paper)

  1. Fast response of carbon monoxide gas sensors using a highly porous network of ZnO nanoparticles decorated on 3D reduced graphene oxide

    Science.gov (United States)

    Ha, Nguyen Hai; Thinh, Dao Duc; Huong, Nguyen Thanh; Phuong, Nguyen Huy; Thach, Phan Duy; Hong, Hoang Si

    2018-03-01

    Zinc oxide (ZnO) nanoparticles loaded onto 3D reduced graphene oxide (3D-RGO) for carbon monoxide (CO) sensing were synthesized using hydrothermal method. The highly porous ZnO/3D-RGO configuration was stable without collapsing and was deposited on the micro-heater of the CO gas sensor. The resulting CO gas sensor displayed high sensitivity, fast response/recovery, and good linearity. The sensor achieved a response value of 85.2% for 1000 ppm CO at a working temperature of 200 °C. The response and recovery times of the sensor were 7 and 9 s for 1000 ppm CO at 200 °C. Similarly, the response value, response time, and recovery time of the sensor at room temperature were 27.5%, 14 s, and 15 s, respectively. The sensor demonstrated a distinct response to various CO concentrations in the range of 1-1000 ppm and good selectivity toward CO gas. In addition, the sensor exhibited good repeatability in multi-cycle and long-term stability.

  2. The Neighboring Column Approximation (NCA) – A fast approach for the calculation of 3D thermal heating rates in cloud resolving models

    International Nuclear Information System (INIS)

    Klinger, Carolin; Mayer, Bernhard

    2016-01-01

    Due to computational costs, radiation is usually neglected or solved in plane parallel 1D approximation in today's numerical weather forecast and cloud resolving models. We present a fast and accurate method to calculate 3D heating and cooling rates in the thermal spectral range that can be used in cloud resolving models. The parameterization considers net fluxes across horizontal box boundaries in addition to the top and bottom boundaries. Since the largest heating and cooling rates occur inside the cloud, close to the cloud edge, the method needs in first approximation only the information if a grid box is at the edge of a cloud or not. Therefore, in order to calculate the heating or cooling rates of a specific grid box, only the directly neighboring columns are used. Our so-called Neighboring Column Approximation (NCA) is an analytical consideration of cloud side effects which can be considered a convolution of a 1D radiative transfer result with a kernel or radius of 1 grid-box (5 pt stencil) and which does usually not break the parallelization of a cloud resolving model. The NCA can be easily applied to any cloud resolving model that includes a 1D radiation scheme. Due to the neglect of horizontal transport of radiation further away than one model column, the NCA works best for model resolutions of about 100 m or lager. In this paper we describe the method and show a set of applications of LES cloud field snap shots. Correction terms, gains and restrictions of the NCA are described. Comprehensive comparisons to the 3D Monte Carlo Model MYSTIC and a 1D solution are shown. In realistic cloud fields, the full 3D simulation with MYSTIC shows cooling rates up to −150 K/d (100 m resolution) while the 1D solution shows maximum coolings of only −100 K/d. The NCA is capable of reproducing the larger 3D cooling rates. The spatial distribution of the heating and cooling is improved considerably. Computational costs are only a factor of 1.5–2 higher compared to a 1D

  3. Comparison of 2D and 3D algorithms for adding a margin to the gross tumor volume in the conformal radiotherapy planning of prostate cancer

    International Nuclear Information System (INIS)

    Khoo, V.S.; Bedford, J.L.; Webb, S.; Dearnaley, D.P.

    1997-01-01

    Purpose: To evaluate the adequacy of tumor volume coverage using a three dimensional (3D) margin growing algorithm compared to a two dimensional (2D) margin growing algorithm in the conformal radiotherapy planning of prostate cancer. Methods and Materials: Two gross tumor volumes (GTV) were segmented in each of ten patients with localized prostate cancer: prostate gland only (PO) and prostate with seminal vesicles (PSV). A margin of 10 mm was applied to these two groups (PO and PSV) using both the 2D and 3D margin growing algorithms. The true planning target volume (PTV) was defined as the region delineated by the 3D algorithm. Adequacy of geometric coverage of the GTV with the two algorithms was examined throughout the target volume. Discrepancies between the two margin methods were measured in the transaxial plane. Results: The 2D algorithm underestimated the PTV by 17% (range 12-20) in the PO group and by 20% (range 13-28) for the PSV group when compared to the 3D algorithm. For both the PO and PSV groups, the inferior coverage of the PTV was consistently underestimated by the 2D margin algorithm when compared to the 3D margins with a mean radial distance of 4.8 mm (range 0-10). In the central region of the prostate gland, the anterior, posterior, and lateral PTV borders were underestimated with the 2D margin in both the PO and PSV groups by a mean of 3.6 mm (range 0-9), 2.1 mm (range 0-8), and 1.8 (range 0-9) respectively. The PTV coverage of the PO group superiorly was radially underestimated by 4.5mm (range 0-14) when comparing the 2D margins to the 3D margins. For the PSV group, the junction region between the prostate and the seminal vesicles was underestimated by the 2D margin by a mean transaxial distance of 18.1 mm in the anterior PTV border (range 4-30), 7.2 mm posteriorly (range 0-20), and 3.7 mm laterally (range 0-14). The superior region of the seminal vesicles in the PSV group was also consistently underestimated with a radial discrepancy of 3.3 mm

  4. Mechanical behavior of a fast reactor core: Application of the 3D codes to SUPER PHENIX 1

    International Nuclear Information System (INIS)

    Bernard, A.; Masoni, P.; Dorsselaere, J.P. van

    1983-01-01

    The series of the 3-dimensional mechanical codes of a fast reactor core was used for the first time within the framework of a design study of an industrial reactor: SUPER-PHENIX 1. These codes are the following ones: - ARGOH which calculates the behavior of an isolated subassembly. - HARMONIE which calculates the core mechanical equilibrium - TRACAR which yields a graphic visualization of HARMONIE results, and calculates the handling forces and support reactions - HARMOREA which calculates the reactivity variations between given equilibrium states (for instance: pads effect and diagrid effect); now at the end of its development. The calculations were performed on 1/3 of the SPX1 core. Their purpose is double: - on the one hand, to check design criteria, and provide the loadings for the subassembly mechanical design studies; on the other hand, to evaluate the reactivity effects, related to the horizontal core deformations, and useful for operation and safety studies. The results of these calculations showed that the design criteria were verified for the contractual lifetime of the subassemblies. (orig.)

  5. Fine 3D neutronic characterization of a gas-cooled fast reactor based on plate-type sub-assemblies

    International Nuclear Information System (INIS)

    Bosq, J. C.; Peneliau, Y.; Rimpault, G.; Vanier, M.

    2006-01-01

    CEA neutronic studies have allowed the definition of a first 2400 MWth reference gas-cooled fast reactor core using plate-type sub-assemblies, for which the main neutronic characteristics were calculated by the so-called ERANOS 'design calculation scheme' relying on several method approximations. The last stage has consisted in a new refine characterization, using the reference calculation scheme, in order to confirm the impact of the approximations of the design route. A first core lay-out taking into account control rods was proposed and the reactivity penalty due to the control rod introduction in this hexagonal core lay-out was quantified. A new adjusted core was defined with an increase of the plutonium content. This leads to a significant decrease of the breeding gain which needs to be recovered in future design evolutions in order to achieve the self breeding goal. Finally, the safety criteria associated to the control rods were calculated with a first estimation of the uncertainties. All these criteria are respected, even if the safety analysis of GFR concepts and the determination of these uncertainties should be further studied and improved. (authors)

  6. Development of an automated 3D segmentation program for volume quantification of body fat distribution using CT

    International Nuclear Information System (INIS)

    Ohshima, Shunsuke; Yamamoto, Shuji; Yamaji, Taiki

    2008-01-01

    The objective of this study was to develop a computing tool for full-automatic segmentation of body fat distributions on volumetric CT images. We developed an algorithm to automatically identify the body perimeter and the inner contour that separates visceral fat from subcutaneous fat. Diaphragmatic surfaces can be extracted by model-based segmentation to match the bottom surface of the lung in CT images for determination of the upper limitation of the abdomen. The functions for quantitative evaluation of abdominal obesity or obesity-related metabolic syndrome were implemented with a prototype three-dimensional (3D) image processing workstation. The volumetric ratios of visceral fat to total fat and visceral fat to subcutaneous fat for each subject can be calculated. Additionally, color intensity mapping of subcutaneous areas and the visceral fat layer is quite obvious in understanding the risk of abdominal obesity with the 3D surface display. Preliminary results obtained have been useful in medical checkups and have contributed to improved efficiency in checking obesity throughout the whole range of the abdomen with 3D visualization and analysis. (author)

  7. Comparison of 2D and 3D algorithms for adding a margin to the gross tumor volume in the conformal radiotherapy planning of prostate cancer

    International Nuclear Information System (INIS)

    Khoo, Vincent S.; Bedford, James L.; Webb, Steve; Dearnaley, David P.

    1998-01-01

    Purpose: To evaluate the adequacy of tumor volume coverage using a three-dimensional (3D) margin-growing algorithm compared to a two-dimensional (2D) margin-growing algorithm in the conformal radiotherapy planning of prostate cancer. Methods and Materials: Two gross tumor volumes (GTV) were segmented in each of 10 patients with localized prostate cancer; prostate gland only (PO) and prostate with seminal vesicles (PSV). A predetermined margin of 10 mm was applied to these two groups (PO and PSV) using both 2D and 3D margin-growing algorithms. The 2D algorithm added a transaxial margin to each GTV slice, whereas the 3D algorithm added a volumetric margin all around the GTV. The true planning target volume (PTV) was defined as the region delineated by the 3D algorithm. The adequacy of geometric coverage of the GTV by the two algorithms was examined in a series of transaxial planes throughout the target volume. Results: The 2D margin-growing algorithm underestimated the PTV by 17% (range 12-20) in the PO group and by 20% (range 13-28) for the PSV group when compared to the 3D-margin algorithm. For the PO group, the mean transaxial difference between the 2D and 3D algorithm was 3.8 mm inferiorly (range 0-20), 1.8 mm centrally (range 0-9), and 4.4 mm superiorly (range 0-22). Considering all of these regions, the mean discrepancy anteriorly was 5.1 mm (range 0-22), posteriorly 2.2 (range 0-20), right border 2.8 mm (range 0-14), and left border 3.1 mm (range 0-12). For the PSV group, the mean discrepancy in the inferior region was 3.8 mm (range 0-20), central region of the prostate was 1.8 mm ( range 0-9), the junction region of the prostate and the seminal vesicles was 5.5 mm (range 0-30), and the superior region of the seminal vesicles was 4.2 mm (range 0-55). When the different borders were considered in the PSV group, the mean discrepancies for the anterior, posterior, right, and left borders were 6.4 mm (range 0-55), 2.5 mm (range 0-20), 2.6 mm (range 0-14), and 3

  8. A dosimetric comparison of 3D-CRT, IMRT, and static tomotherapy with an SIB for large and small breast volumes

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, Andrea [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Central Coast Cancer Centre, Gosford Hospital, Gosford, New South Wales (Australia); Atyeo, John, E-mail: john.atyeo@sydney.edu.au [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Cox, Jennifer [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, New South Wales (Australia); Rinks, Marianne [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Radiation Oncology, Cancer Services, Illawarra Shoalhaven Local Health District, Wollongong, New South Wales (Australia); Morgia, Marita; Lamoury, Gillian [Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, New South Wales (Australia)

    2014-07-01

    Radiation therapy to the breast is a complex task, with many different techniques that can be employed to ensure adequate dose target coverage while minimizing doses to the organs at risk. This study compares the dose planning outcomes of 3 radiation treatment modalities, 3 dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and static tomotherapy, for left-sided whole-breast radiation treatment with a simultaneous integrated boost (SIB). Overall, 20 patients with left-sided breast cancer were separated into 2 cohorts, small and large, based on breast volume. Dose plans were produced for each patient using 3D-CRT, IMRT, and static tomotherapy. All patients were prescribed a dose of 45 Gy in 20 fractions to the breast with an SIB of 56 Gy in 20 fractions to the tumor bed and normalized so that D{sub 98%} > 95% of the prescription dose. Dosimetric comparisons were made between the 3 modalities and the interaction of patient size. All 3 modalities offered adequate planning target volume (PTV) coverage with D{sub 98%} > 95% and D{sub 2%} < 107%. Static tomotherapy offered significantly improved (p = 0.006) dose homogeneity to the PTV{sub boost} {sub eval} (0.079 ± 0.011) and breast minus the SIB volume (Breast{sub SIB}) (p < 0.001, 0.15 ± 0.03) compared with the PTV{sub boost} {sub eval} (0.085 ± 0.008, 0.088 ± 0.12) and Breast{sub SIB} (0.22 ± 0.05, 0.23 ± 0.03) for IMRT and 3D-CRT, respectively. Static tomotherapy also offered statistically significant reductions (p < 0.001) in doses to the ipsilateral lung mean dose of 6.79 ± 2.11 Gy compared with 7.75 ± 2.54 Gy and 8.29 ± 2.76 Gy for IMRT and 3D-CRT, respectively, and significantly (p < 0.001) reduced heart doses (mean = 2.83 ± 1.26 Gy) compared to both IMRT and 3D-CRT (mean = 3.70 ± 1.44 Gy and 3.91 ± 1.58 Gy). Static tomotherapy is the dosimetrically superior modality for the whole breast with an SIB compared with IMRT and 3D-CRT. IMRT is superior to 3D

  9. Assessment of pulmonary vasculature volume with automated threshold-based 3D quantitative CT volumetry: In vitro and in vivo validation

    International Nuclear Information System (INIS)

    Liu Jingzhe; Wu Qingyu; Xu Yufeng; Bai Yan; Liu Zhibo; Li Hongyin; Zhu Jiemin

    2012-01-01

    Objectives: To validate the ability of threshold-based 3D CT volumetry to enable measurement of volume of visible pulmonary vessels on CT. Materials and methods: In vivo, 3D CT volumetry was validated in seven phantoms that consisted of silicone tubes embedded in a foam block. With the true volume value as reference standard, the accuracy of CT measurement at various lower thresholds of −600 HU, −500 HU, −300 HU and −200 HU were compared. The volume measurements obtained when filled with varied concentration of iodinated contrast media (1:100, 1:200 and 1:500) were also compared. In vivo validation was performed in sixteen patients (9 men, 7 women; mean age, 52.1 years). Inter-scan and inter-observer agreement and reproducibility for pulmonary vasculature volume measurement were evaluated with Bland–Altman analysis. Results: In vitro, the mean value measured under lower threshold of −300 HU (relative error = 1.5%) were the closest to the true values and have no significant difference (P = 0.375). There were no significant differences among the phantom measurement values with different filled concentration (1:100, 1:200 and 1:500). In vivo, the inter-scan reproducibility of volume measurements was good, with a correlation coefficient of 0.82 and ICC (intraclass correlation coefficient) of 0.86. Inter-observer agreement was excellent with a correlation coefficient of 0.91 and ICC of 0.95. Conclusions: The threshold-based 3D quantitative CT volumetry enables accurate and reproducible measurement of pulmonary vessels volume.

  10. Validity and reliability of a novel 3D scanner for assessment of the shape and volume of amputees' residual limb models.

    Directory of Open Access Journals (Sweden)

    Elena Seminati

    Full Text Available Objective assessment methods to monitor residual limb volume following lower-limb amputation are required to enhance practitioner-led prosthetic fitting. Computer aided systems, including 3D scanners, present numerous advantages and the recent Artec Eva scanner, based on laser free technology, could potentially be an effective solution for monitoring residual limb volumes.The aim of this study was to assess the validity and reliability of the Artec Eva scanner (practical measurement against a high precision laser 3D scanner (criterion measurement for the determination of residual limb model shape and volume.Three observers completed three repeat assessments of ten residual limb models, using both the scanners. Validity of the Artec Eva scanner was assessed (mean percentage error <2% and Bland-Altman statistics were adopted to assess the agreement between the two scanners. Intra and inter-rater reliability (repeatability coefficient <5% of the Artec Eva scanner was calculated for measuring indices of residual limb model volume and shape (i.e. residual limb cross sectional areas and perimeters.Residual limb model volumes ranged from 885 to 4399 ml. Mean percentage error of the Artec Eva scanner (validity was 1.4% of the criterion volumes. Correlation coefficients between the Artec Eva and the Romer determined variables were higher than 0.9. Volume intra-rater and inter-rater reliability coefficients were 0.5% and 0.7%, respectively. Shape percentage maximal error was 2% at the distal end of the residual limb, with intra-rater reliability coefficients presenting the lowest errors (0.2%, both for cross sectional areas and perimeters of the residual limb models.The Artec Eva scanner is a valid and reliable method for assessing residual limb model shapes and volumes. While the method needs to be tested on human residual limbs and the results compared with the current system used in clinical practice, it has the potential to quantify shape and volume

  11. 3D modeling of forces between magnet and HTS in a levitation system using new approach of the control volume method based on an unstructured grid

    Energy Technology Data Exchange (ETDEWEB)

    Alloui, L., E-mail: lotfi.alloui@lgep.supelec.fr [Laboratoire de Genie Electrique de Paris - LGEP, CNRS UMR 8507, Supelec, Universite Pierre et Marie Curie-Paris 6, Universite Paris Sud-Paris 11, Plateau de Moulon, 11 rue Joliot Curie, 91192 Gif-Sur-Yvette Cedex (France); Laboratoire de modelisation des systemes energetiques (LMSE), Universite de Biskra, 07000 Biskra (Algeria); Bouillault, F., E-mail: bouillault@lgep.supelec.fr [Laboratoire de Genie Electrique de Paris - LGEP, CNRS UMR 8507, Supelec, Universite Pierre et Marie Curie-Paris 6, Universite Paris Sud-Paris 11, Plateau de Moulon, 11 rue Joliot Curie, 91192 Gif-Sur-Yvette Cedex (France); Bernard, L., E-mail: laurent.bernardl@lgep.supelc.fr [Laboratoire de Genie Electrique de Paris - LGEP, CNRS UMR 8507, Supelec, Universite Pierre et Marie Curie-Paris 6, Universite Paris Sud-Paris 11, Plateau de Moulon, 11 rue Joliot Curie, 91192 Gif-Sur-Yvette Cedex (France); Leveque, J., E-mail: jean.leveque@green.uhp-nancy.fr [Groupe de recherche en electronique et electrotechnique de Nancy, Universite Henry Poincare, BP 239, 54506 Vandoeuvre les Nancy (France)

    2012-05-15

    In this paper we present new 3D numerical model to calculate the vertical and the guidance forces in high temperature superconductors taking into account the influence of the flux creep phenomena. In the suggested numerical model, we adopt a new approach of the control volume method. This approach is based on the use of an unstructured grid which can be used to model more complex geometries. A comparison of the control volume method results with experiments verifies the validity of this approach and the proposed numerical model. Based on this model, the levitation force's relaxation at different temperatures was also studied.

  12. pySeismicFMM: Python based Travel Time Calculation in Regular 2D and 3D Grids in Cartesian and Geographic Coordinates using Fast Marching Method

    Science.gov (United States)

    Wilde-Piorko, M.; Polkowski, M.

    2016-12-01

    Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation final release of a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. Source code of pySeismicFMM will be published before Fall Meeting. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.

  13. An improved data integration algorithm to constrain the 3D displacement field induced by fast deformation phenomena tested on the Napa Valley earthquake

    Science.gov (United States)

    Polcari, Marco; Fernández, José; Albano, Matteo; Bignami, Christian; Palano, Mimmo; Stramondo, Salvatore

    2017-12-01

    In this work, we propose an improved algorithm to constrain the 3D ground displacement field induced by fast surface deformations due to earthquakes or landslides. Based on the integration of different data, we estimate the three displacement components by solving a function minimization problem from the Bayes theory. We exploit the outcomes from SAR Interferometry (InSAR), Global Positioning System (GNSS) and Multiple Aperture Interferometry (MAI) to retrieve the 3D surface displacement field. Any other source of information can be added to the processing chain in a simple way, being the algorithm computationally efficient. Furthermore, we use the intensity Pixel Offset Tracking (POT) to locate the discontinuity produced on the surface by a sudden deformation phenomenon and then improve the GNSS data interpolation. This approach allows to be independent from other information such as in-situ investigations, tectonic studies or knowledge of the data covariance matrix. We applied such a method to investigate the ground deformation field related to the 2014 Mw 6.0 Napa Valley earthquake, occurred few kilometers from the San Andreas fault system.

  14. Automatic intensity-based 3D-to-2D registration of CT volume and dual-energy digital radiography for the detection of cardiac calcification

    Science.gov (United States)

    Chen, Xiang; Gilkeson, Robert; Fei, Baowei

    2007-03-01

    We are investigating three-dimensional (3D) to two-dimensional (2D) registration methods for computed tomography (CT) and dual-energy digital radiography (DR) for the detection of coronary artery calcification. CT is an established tool for the diagnosis of coronary artery diseases (CADs). Dual-energy digital radiography could be a cost-effective alternative for screening coronary artery calcification. In order to utilize CT as the "gold standard" to evaluate the ability of DR images for the detection and localization of calcium, we developed an automatic intensity-based 3D-to-2D registration method for 3D CT volumes and 2D DR images. To generate digital rendering radiographs (DRR) from the CT volumes, we developed three projection methods, i.e. Gaussian-weighted projection, threshold-based projection, and average-based projection. We tested normalized cross correlation (NCC) and normalized mutual information (NMI) as similarity measurement. We used the Downhill Simplex method as the search strategy. Simulated projection images from CT were fused with the corresponding DR images to evaluate the localization of cardiac calcification. The registration method was evaluated by digital phantoms, physical phantoms, and clinical data sets. The results from the digital phantoms show that the success rate is 100% with mean errors of less 0.8 mm and 0.2 degree for both NCC and NMI. The registration accuracy of the physical phantoms is 0.34 +/- 0.27 mm. Color overlay and 3D visualization of the clinical data show that the two images are registered well. This is consistent with the improvement of the NMI values from 0.20 +/- 0.03 to 0.25 +/- 0.03 after registration. The automatic 3D-to-2D registration method is accurate and robust and may provide a useful tool to evaluate the dual-energy DR images for the detection of coronary artery calcification.

  15. Automation of 3D reconstruction of neural tissue from large volume of conventional serial section transmission electron micrographs.

    Science.gov (United States)

    Mishchenko, Yuriy

    2009-01-30

    We describe an approach for automation of the process of reconstruction of neural tissue from serial section transmission electron micrographs. Such reconstructions require 3D segmentation of individual neuronal processes (axons and dendrites) performed in densely packed neuropil. We first detect neuronal cell profiles in each image in a stack of serial micrographs with multi-scale ridge detector. Short breaks in detected boundaries are interpolated using anisotropic contour completion formulated in fuzzy-logic framework. Detected profiles from adjacent sections are linked together based on cues such as shape similarity and image texture. Thus obtained 3D segmentation is validated by human operators in computer-guided proofreading process. Our approach makes possible reconstructions of neural tissue at final rate of about 5 microm3/manh, as determined primarily by the speed of proofreading. To date we have applied this approach to reconstruct few blocks of neural tissue from different regions of rat brain totaling over 1000microm3, and used these to evaluate reconstruction speed, quality, error rates, and presence of ambiguous locations in neuropil ssTEM imaging data.

  16. Pulmonary nodules: sensitivity of maximum intensity projection versus that of volume rendering of 3D multidetector CT data

    NARCIS (Netherlands)

    Peloschek, Philipp; Sailer, Johannes; Weber, Michael; Herold, Christian J.; Prokop, Mathias; Schaefer-Prokop, Cornelia

    2007-01-01

    PURPOSE: To prospectively compare maximum intensity projection (MIP) and volume rendering (VR) of multidetector computed tomographic (CT) data for the detection of small intrapulmonary nodules. MATERIALS AND METHODS: This institutional review board-approved prospective study included 20 oncology

  17. Value of 3D-Volume Rendering in the Assessment of Coronary Arteries with Retrospectively Ecg-Gated Multislice Spiral CT

    International Nuclear Information System (INIS)

    Mahnken, A.H.; Wildberger, J.E.; Dedden, K.; Schmitz-Rode, T.; Guenther, R.W.; Sinha, A.M.; Hoffmann, R.; Stanzel, S.

    2003-01-01

    Purpose: To assess the diagnostic value and measurement precision of 3D volume rendering technique (3D-VRT) from retrospectively ECG-gated multislice spiral CT (MSCT) data sets for imaging of the coronary arteries. Material and Methods: In 35 patients, retrospectively ECG-gated MSCT of the heart using a four detector row MSCT scanner with a standardized examination protocol was performed as well as quantitative X-ray coronary angiography (QCA). The MSCT data was assessed on segmental basis using 3D-VRT exclusively. The coronary artery diameters were measured at the origin of each main coronary branch and 1 cm, 3 cm and 5 cm distally. The minimum, maximum and mean diameters were determined from MSCT angiography and compared to QCA. Results: A total of 353 of 525 (67.2%) coronary artery segments were assessable by MSCT angiography. The proximal segments were more often assessable when compared to the distal segments. Stenoses were detected with a sensitivity of 82.6% and a specificity of 92.8%. According to the Bland-Altman method the mean differences between QCA and MSCT ranged from 0.55 to 1.07 mm with limits of agreement from 2.2 mm to 2.7 mm. Conclusion: When compared to QCA, the ability of 3D-VRT to quantitatively assess coronary artery diameters and coronary artery stenoses is insufficient for clinical purposes

  18. Summary Report on Phase I Results from the 3D Printing in Zero G Technology Demonstration Mission, Volume I

    Science.gov (United States)

    Prater, T. J.; Bean, Q. A.; Beshears, R. D.; Rolin, T. D.; Werkheiser, N. J.; Ordonez, E. A.; Ryan, R. M.; Ledbetter, F. E., III

    2016-01-01

    Human space exploration to date has been confined to low-Earth orbit and the Moon. The International Space Station (ISS) provides a unique opportunity for researchers to prove out the technologies that will enable humans to safely live and work in space for longer periods of time and venture beyond the Earth/Moon system. The ability to manufacture parts in-space rather than launch them from Earth represents a fundamental shift in the current risk and logistics paradigm for human spaceflight. In September 2014, NASA, in partnership with Made In Space, Inc., launched the 3D Printing in Zero-G technology demonstration mission to explore the potential of additive manufacturing for in-space applications and demonstrate the capability to manufacture parts and tools on orbit using fused deposition modeling. This Technical Publication summarizes the results of testing to date of the ground control and flight prints from the first phase of this ISS payload.

  19. A fast dual wavelength laser beam fluid-less optical CT scanner for radiotherapy 3D gel dosimetry II: dosimetric performance

    Science.gov (United States)

    Ramm, Daniel

    2018-02-01

    New clinical radiotherapy dosimetry systems need comprehensive demonstration of measurement quality. Practicality and reliability are other important aspects for clinical dosimeters. In this work the performance of an optical CT scanner for true 3D dosimetry is assessed using a radiochromic gel dosimeter. The fluid-less scanner utilised dual lasers to avoid the necessity for pre-irradiation scans and give greater robustness of image quality, enhancing practicality. Calibration methods using both cuvettes and reconstructed volumes were developed. Dosimetric accuracy was similar for dual and single wavelength measurements, except that cuvette calibration reliability was reduced for dual wavelength without pre-irradiation scanning. Detailed performance parameters were specified for the dosimetry system indicating the suitability for clinical use. The most significant limitations of the system were due to the gel dosimeter rather than the optical CT scanner. Quality assurance guidelines were developed to maintain dosimetry system performance in routine use.

  20. Multi-slice CT (MSCT) in cardiac function imaging: threshold-value-supported 3D volume reconstructions to determine the left ventricular ejection fraction in comparison to MRI

    International Nuclear Information System (INIS)

    Ehrhard, K.; Oberholzer, K.; Gast, K.; Mildenberger, P.; Kreitner, K.F.; Thelen, M.

    2002-01-01

    Purpose: To assess MSCT of the heart to determining left ventricular ejection fraction (EF) based on threshold-value-supported 3D volume reconstructions compared to MRI. Methods: Cardiac MSCT was performed in 7 patients. Images were reconstructed during end-systolic and end-diastolic phases of the cardiac cycle and transformed to 3D volumes to determine end-systolic (ESV) and end-diastolic volume (EDV) by using different lower threshold values: besides fixed lower threshold values, identical for each image sequence, individual lower threshold values dependent on contrast enhancement of the left ventricle were applied. The latter represent the mean value calculated by combining the average CT-density of the myocardium and the contrast-enhanced blood in the left ventricle. The EF derived from ESV and EDV. Results: The best correlation with MR imaging was obtained for ESV and EDV by using the individual lower threshold values for the respective sequence. The correlation coefficient for ESV was 0.95 and for EDV it was 0.93. On average, the ESV was overestimated by 3.72 ml, while the ESD was underestimated by 2.85 ml. The respective standard deviation for the ESV was 14,87 ml, for the EDV it was 26.83 ml. On average, the EF was underestimated by 3.57% with a standard deviation of 9.43% and a correlation coefficient of 0.83 in comparison to MRI. Conclusion: The threshold-value-supported 3D volume reconstruction of the left ventricle represents a good method to determine the left ventricular function parameters. Due to the differences in the contrast enhancement, the use of an individual lower threshold value for every image sequence is of particular importance. (orig.) [de

  1. Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta

    Science.gov (United States)

    Martyr-Koller, R.C.; Kernkamp, H.W.J.; Van Dam, Anne A.; Mick van der Wegen,; Lucas, Lisa; Knowles, N.; Jaffe, B.; Fregoso, T.A.

    2017-01-01

    A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period.Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.

  2. Application of an unstructured 3D finite volume numerical model to flows and salinity dynamics in the San Francisco Bay-Delta

    Science.gov (United States)

    Martyr-Koller, R. C.; Kernkamp, H. W. J.; van Dam, A.; van der Wegen, M.; Lucas, L. V.; Knowles, N.; Jaffe, B.; Fregoso, T. A.

    2017-06-01

    A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period. Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.

  3. Sodium fast reactor safety and licensing research plan. Volume II.

    Energy Technology Data Exchange (ETDEWEB)

    Ludewig, H. (Brokhaven National Laboratory, Upton, NY); Powers, D. A.; Hewson, John C.; LaChance, Jeffrey L.; Wright, A. (Argonne National Laboratory, Argonne, IL); Phillips, J.; Zeyen, R. (Institute for Energy Petten, Saint-Paul-lez-Durance, France); Clement, B. (IRSN/DPAM.SEMIC Bt 702, Saint-Paul-lez-Durance, France); Garner, Frank (Radiation Effects Consulting, Richland, WA); Walters, Leon (Advanced Reactor Concepts, Los Alamos, NM); Wright, Steve; Ott, Larry J. (Oak Ridge National Laboratory, Oak Ridge, TN); Suo-Anttila, Ahti Jorma; Denning, Richard (Ohio State University, Columbus, OH); Ohshima, Hiroyuki (Japan Atomic Energy Agency, Ibaraki, Japan); Ohno, S. (Japan Atomic Energy Agency, Ibaraki, Japan); Miyhara, S. (Japan Atomic Energy Agency, Ibaraki, Japan); Yacout, Abdellatif (Argonne National Laboratory, Argonne, IL); Farmer, M. (Argonne National Laboratory, Argonne, IL); Wade, D. (Argonne National Laboratory, Argonne, IL); Grandy, C. (Argonne National Laboratory, Argonne, IL); Schmidt, R.; Cahalen, J. (Argonne National Laboratory, Argonne, IL); Olivier, Tara Jean; Budnitz, R. (Lawrence Berkeley National Laboratory, Berkeley, CA); Tobita, Yoshiharu (Japan Atomic Energy Agency, Ibaraki, Japan); Serre, Frederic (Centre d' %C3%94etudes nucl%C3%94eaires de Cadarache, Cea, France); Natesan, Ken (Argonne National Laboratory, Argonne, IL); Carbajo, Juan J. (Oak Ridge National Laboratory, Oak Ridge, TN); Jeong, Hae-Yong (Korea Atomic Energy Research Institute, Daejeon, Korea); Wigeland, Roald (Idaho National Laboratory, Idaho Falls, ID); Corradini, Michael (University of Wisconsin-Madison, Madison, WI); Thomas, Justin (Argonne National Laboratory, Argonne, IL); Wei, Tom (Argonne National Laboratory, Argonne, IL); Sofu, Tanju (Argonne National Laboratory, Argonne, IL); Flanagan, George F. (Oak Ridge National Laboratory, Oak Ridge, TN); Bari, R. (Brokhaven National Laboratory, Upton, NY); Porter D. (Idaho National Laboratory, Idaho Falls, ID); Lambert, J. (Argonne National Laboratory, Argonne, IL); Hayes, S. (Idaho National Laboratory, Idaho Falls, ID); Sackett, J. (Idaho National Laboratory, Idaho Falls, ID); Denman, Matthew R.

    2012-05-01

    Expert panels comprised of subject matter experts identified at the U.S. National Laboratories (SNL, ANL, INL, ORNL, LBL, and BNL), universities (University of Wisconsin and Ohio State University), international agencies (IRSN, CEA, JAEA, KAERI, and JRC-IE) and private consultation companies (Radiation Effects Consulting) were assembled to perform a gap analysis for sodium fast reactor licensing. Expert-opinion elicitation was performed to qualitatively assess the current state of sodium fast reactor technologies. Five independent gap analyses were performed resulting in the following topical reports: (1) Accident Initiators and Sequences (i.e., Initiators/Sequences Technology Gap Analysis), (2) Sodium Technology Phenomena (i.e., Advanced Burner Reactor Sodium Technology Gap Analysis), (3) Fuels and Materials (i.e., Sodium Fast Reactor Fuels and Materials: Research Needs), (4) Source Term Characterization (i.e., Advanced Sodium Fast Reactor Accident Source Terms: Research Needs), and (5) Computer Codes and Models (i.e., Sodium Fast Reactor Gaps Analysis of Computer Codes and Models for Accident Analysis and Reactor Safety). Volume II of the Sodium Research Plan consolidates the five gap analysis reports produced by each expert panel, wherein the importance of the identified phenomena and necessities of further experimental research and code development were addressed. The findings from these five reports comprised the basis for the analysis in Sodium Fast Reactor Research Plan Volume I.

  4. Sodium fast reactor safety and licensing research plan - Volume II

    International Nuclear Information System (INIS)

    Ludewig, H.; Powers, D.A.; Hewson, John C.; LaChance, Jeffrey L.; Wright, A.; Phillips, J.; Zeyen, R.; Clement, B.; Garner, Frank; Walters, Leon; Wright, Steve; Ott, Larry J.; Suo-Anttila, Ahti Jorma; Denning, Richard; Ohshima, Hiroyuki; Ohno, S.; Miyhara, S.; Yacout, Abdellatif; Farmer, M.; Wade, D.; Grandy, C.; Schmidt, R.; Cahalen, J.; Olivier, Tara Jean; Budnitz, R.; Tobita, Yoshiharu; Serre, Frederic; Natesan, Ken; Carbajo, Juan J.; Jeong, Hae-Yong; Wigeland, Roald; Corradini, Michael; Thomas, Justin; Wei, Tom; Sofu, Tanju; Flanagan, George F.; Bari, R.; Porter D.

    2012-01-01

    Expert panels comprised of subject matter experts identified at the U.S. National Laboratories (SNL, ANL, INL, ORNL, LBL, and BNL), universities (University of Wisconsin and Ohio State University), international agencies (IRSN, CEA, JAEA, KAERI, and JRC-IE) and private consultation companies (Radiation Effects Consulting) were assembled to perform a gap analysis for sodium fast reactor licensing. Expert-opinion elicitation was performed to qualitatively assess the current state of sodium fast reactor technologies. Five independent gap analyses were performed resulting in the following topical reports: (1) Accident Initiators and Sequences (i.e., Initiators/Sequences Technology Gap Analysis), (2) Sodium Technology Phenomena (i.e., Advanced Burner Reactor Sodium Technology Gap Analysis), (3) Fuels and Materials (i.e., Sodium Fast Reactor Fuels and Materials: Research Needs), (4) Source Term Characterization (i.e., Advanced Sodium Fast Reactor Accident Source Terms: Research Needs), and (5) Computer Codes and Models (i.e., Sodium Fast Reactor Gaps Analysis of Computer Codes and Models for Accident Analysis and Reactor Safety). Volume II of the Sodium Research Plan consolidates the five gap analysis reports produced by each expert panel, wherein the importance of the identified phenomena and necessities of further experimental research and code development were addressed. The findings from these five reports comprised the basis for the analysis in Sodium Fast Reactor Research Plan Volume I.

  5. Automated volume analysis of head and neck lesions on CT scans using 3D level set segmentation

    International Nuclear Information System (INIS)

    Street, Ethan; Hadjiiski, Lubomir; Sahiner, Berkman; Gujar, Sachin; Ibrahim, Mohannad; Mukherji, Suresh K.; Chan, Heang-Ping

    2007-01-01

    The authors have developed a semiautomatic system for segmentation of a diverse set of lesions in head and neck CT scans. The system takes as input an approximate bounding box, and uses a multistage level set to perform the final segmentation. A data set consisting of 69 lesions marked on 33 scans from 23 patients was used to evaluate the performance of the system. The contours from automatic segmentation were compared to both 2D and 3D gold standard contours manually drawn by three experienced radiologists. Three performance metric measures were used for the comparison. In addition, a radiologist provided quality ratings on a 1 to 10 scale for all of the automatic segmentations. For this pilot study, the authors observed that the differences between the automatic and gold standard contours were larger than the interobserver differences. However, the system performed comparably to the radiologists, achieving an average area intersection ratio of 85.4% compared to an average of 91.2% between two radiologists. The average absolute area error was 21.1% compared to 10.8%, and the average 2D distance was 1.38 mm compared to 0.84 mm between the radiologists. In addition, the quality rating data showed that, despite the very lax assumptions made on the lesion characteristics in designing the system, the automatic contours approximated many of the lesions very well

  6. Role of volume rendered 3-D computed tomography in conservative management of trauma-related thoracic injuries.

    LENUS (Irish Health Repository)

    OʼLeary, Donal Peter

    2012-09-01

    Pneumatic nail guns are a tool used commonly in the construction industry and are widely available. Accidental injuries from nail guns are common, and several cases of suicide using a nail gun have been reported. Computed tomographic (CT) imaging, together with echocardiography, has been shown to be the gold standard for investigation of these cases. We present a case of a 55-year-old man who presented to the accident and emergency unit of a community hospital following an accidental pneumatic nail gun injury to his thorax. Volume-rendered CT of the thorax allowed an accurate assessment of the thoracic injuries sustained by this patient. As there was no evidence of any acute life-threatening injury, a sternotomy was avoided and the patient was observed closely until discharge. In conclusion, volume-rendered 3-dimensional CT can greatly help in the decision to avoid an unnecessary sternotomy in patients with a thoracic nail gun injury.

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

    Science.gov (United States)

    Abu Anas, Emran Mohammad; Kim, Jae Gon; Lee, Soo Yeol; Kamrul Hasan, Md

    2011-10-01

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

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

    International Nuclear Information System (INIS)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul; Kim, Jae Gon; Lee, Soo Yeol

    2011-01-01

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

  9. Evaluation of left atrial function by multidetector computed tomography before left atrial radiofrequency-catheter ablation: Comparison of a manual and automated 3D volume segmentation method

    International Nuclear Information System (INIS)

    Wolf, Florian; Ourednicek, Petr; Loewe, Christian; Richter, Bernhard; Goessinger, Heinz David; Gwechenberger, Marianne; Plank, Christina; Schernthaner, Ruediger Egbert; Toepker, Michael; Lammer, Johannes; Feuchtner, Gudrun M.

    2010-01-01

    Introduction: The purpose of this study was to compare a manual and automated 3D volume segmentation tool for evaluation of left atrial (LA) function by 64-slice multidetector-CT (MDCT). Methods and materials: In 33 patients with paroxysmal atrial fibrillation a MDCT scan was performed before radiofrequency-catheter ablation. Atrial function (minimal volume (LAmin), maximal volume (LAmax), stroke volume (SV), ejection fraction (EF)) was evaluated by two readers using a manual and an automatic tool and measurement time was evaluated. Results: Automated LA volume segmentation failed in one patient due to low LA enhancement (103HU). Mean LAmax, LAmin, SV and EF were 127.7 ml, 93 ml, 34.7 ml, 27.1% by the automated, and 122.7 ml, 89.9 ml, 32.8 ml, 26.3% by the manual method with no significant difference (p > 0.05) and high Pearsons correlation coefficients (r = 0.94, r = 0.94, r = 0.82 and r = 0.85, p < 0.0001), respectively. The automated method was significantly faster (p < 0.001). Interobserver variability was low for both methods with Pearson's correlation coefficients between 0.98 and 0.99 (p < 0.0001). Conclusions: Evaluation of LA volume and function with 64-slice MDCT is feasible with a very low interobserver variability. The automatic method is as accurate as the manual method but significantly less time consuming permitting a routine use in clinical practice before RF-catheter ablation.

  10. TomoEED: Fast Edge-Enhancing Denoising of Tomographic Volumes.

    Science.gov (United States)

    Moreno, J J; Martínez-Sánchez, A; Martínez, J A; Garzón, E M; Fernández, J J

    2018-05-29

    TomoEED is an optimized software tool for fast feature-preserving noise filtering of large 3D tomographic volumes on CPUs and GPUs. The tool is based on the anisotropic nonlinear diffusion method. It has been developed with special emphasis in the reduction of the computational demands by using different strategies, from the algorithmic to the high performance computing perspectives. TomoEED manages to filter large volumes in a matter of minutes in standard computers. TomoEED has been developed in C. It is available for Linux platforms at http://www.cnb.csic.es/%7ejjfernandez/tomoeed. gmartin@ual.es, JJ.Fernandez@csic.es. Supplementary data are available at Bioinformatics online.

  11. The cerebellar development in chinese children-a study by voxel-based volume measurement of reconstructed 3D MRI scan.

    Science.gov (United States)

    Wu, Kuan-Hsun; Chen, Chia-Yuan; Shen, Ein-Yiao

    2011-01-01

    Cerebellar disorder was frequently reported to have relation with structural brain volume alteration and/or morphology change. In dealing with such clinical situations, we need a convenient and noninvasive imaging tool to provide clinicians with a means of tracing developmental changes in the cerebellum. Herein, we present a new daily practice method for cerebellum imaging that uses a work station and a software program to process reconstructed 3D neuroimages after MRI scanning. In a 3-y period, 3D neuroimages reconstructed from MRI scans of 50 children aged 0.2-12.7 y were taken. The resulting images were then statistically analyzed against a growth curve. We observed a remarkable increase in the size of the cerebellum in the first 2 y of life. Furthermore, the unmyelinated cerebellum grew mainly between birth and 2 y of age in the postnatal stage. In contrast, the postnatal development of the brain mainly depended on the growth of myelinated cerebellum from birth through adolescence. This study presents basic data from a study of ethnic Chinese children's cerebellums using reconstructed 3D brain images. Based on the technique we introduce here, clinicians can evaluate the growth of the brain.

  12. Coupling of a 3-D vortex particle-mesh method with a finite volume near-wall solver

    Science.gov (United States)

    Marichal, Y.; Lonfils, T.; Duponcheel, M.; Chatelain, P.; Winckelmans, G.

    2011-11-01

    This coupling aims at improving the computational efficiency of high Reynolds number bluff body flow simulations by using two complementary methods and exploiting their respective advantages in distinct parts of the domain. Vortex particle methods are particularly well suited for free vortical flows such as wakes or jets (the computational domain -with non zero vorticity- is then compact and dispersion errors are negligible). Finite volume methods, however, can handle boundary layers much more easily due to anisotropic mesh refinement. In the present approach, the vortex method is used in the whole domain (overlapping domain technique) but its solution is highly underresolved in the vicinity of the wall. It thus has to be corrected by the near-wall finite volume solution at each time step. Conversely, the vortex method provides the outer boundary conditions for the near-wall solver. A parallel multi-resolution vortex particle-mesh approach is used here along with an Immersed Boundary method in order to take the walls into account. The near-wall flow is solved by OpenFOAM® using the PISO algorithm. We validate the methodology on the flow past a sphere at a moderate Reynolds number. F.R.S. - FNRS Research Fellow.

  13. Towards a universal method for calculating hydration free energies: a 3D reference interaction site model with partial molar volume correction.

    Science.gov (United States)

    Palmer, David S; Frolov, Andrey I; Ratkova, Ekaterina L; Fedorov, Maxim V

    2010-12-15

    We report a simple universal method to systematically improve the accuracy of hydration free energies calculated using an integral equation theory of molecular liquids, the 3D reference interaction site model. A strong linear correlation is observed between the difference of the experimental and (uncorrected) calculated hydration free energies and the calculated partial molar volume for a data set of 185 neutral organic molecules from different chemical classes. By using the partial molar volume as a linear empirical correction to the calculated hydration free energy, we obtain predictions of hydration free energies in excellent agreement with experiment (R = 0.94, σ = 0.99 kcal mol (- 1) for a test set of 120 organic molecules).

  14. Computer-assisted operational planning for pediatric abdominal surgery. 3D-visualized MRI with volume rendering; Die computerassistierte Operationsplanung in der Abdominalchirurgie des Kindes. 3D-Visualisierung mittels ''volume rendering'' in der MRT

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, P.; Holland-Cunz, S.; Waag, K.L. [Universitaetsklinikum Heidelberg (Germany). Kinderchirurgie; Troeger, J. [Universitaetsklinikum Heidelberg, (Germany). Paediatrische Radiologie; Schenk, J.P. [Universitaetsklinikum Heidelberg, (Germany). Paediatrische Radiologie; Universitaetsklinikum, Paediatrische Radiologie, Heidelberg (Germany)

    2006-08-15

    Exact surgical planning is necessary for complex operations of pathological changes in anatomical structures of the pediatric abdomen. 3D visualization and computer-assisted operational planning based on CT data are being increasingly used for difficult operations in adults. To minimize radiation exposure and for better soft tissue contrast, sonography and MRI are the preferred diagnostic methods in pediatric patients. Because of manifold difficulties 3D visualization of these MRI data has not been realized so far, even though the field of embryonal malformations and tumors could benefit from this. A newly developed and modified raycasting-based powerful 3D volume rendering software (VG Studio Max 1.2) for the planning of pediatric abdominal surgery is presented. With the help of specifically developed algorithms, a useful surgical planning system is demonstrated. Thanks to the easy handling and high-quality visualization with enormous gain of information, the presented system is now an established part of routine surgical planning. (orig.) [German] Komplexe Operationen bei ausgepraegten pathologischen Veraenderungen anatomischer Strukturen des kindlichen Abdomens benoetigen eine exakte Operationsvorbereitung. 3D-Visualisierung und computerassistierte Operationsplanung anhand von CT-Daten finden fuer schwierige chirurgische Eingriffe bei Erwachsenen in zunehmendem Masse Anwendung. Aus strahlenhygienischen Gruenden und bei besserer Weichteildifferenzierung ist jedoch neben der Sonographie die Magnetresonanztomographie (MRT) bei Kindern das Diagnostikum der Wahl. Die 3D-Visualisierung dieser MRT-Daten ist dabei jedoch aufgrund vielfaeltiger Schwierigkeiten bisher nicht durchgefuehrt worden, obwohl sich das Gebiet embryonaler Fehlbildungen und Tumoren geradezu anbietet. Vorgestellt wird eine weiterentwickelte und an die Fragestellungen der abdominellen Kinderchirurgie angepasste, sehr leistungsstarke raycastingbasierte 3D-volume-rendering-Software (VG Studio Max 1

  15. Efficient solution of 3D electromagnetic eddy-current problems within the finite volume framework of OpenFOAM

    Science.gov (United States)

    Beckstein, Pascal; Galindo, Vladimir; Vukčević, Vuko

    2017-09-01

    Eddy-current problems occur in a wide range of industrial and metallurgical applications where conducting material is processed inductively. Motivated by realising coupled multi-physics simulations, we present a new method for the solution of such problems in the finite volume framework of foam-extend, an extended version of the very popular OpenFOAM software. The numerical procedure involves a semi-coupled multi-mesh approach to solve Maxwell's equations for non-magnetic materials by means of the Coulomb gauged magnetic vector potential A and the electric scalar potential ϕ. The concept is further extended on the basis of the impressed and reduced magnetic vector potential and its usage in accordance with Biot-Savart's law to achieve a very efficient overall modelling even for complex three-dimensional geometries. Moreover, we present a special discretisation scheme to account for possible discontinuities in the electrical conductivity. To complement our numerical method, an extensive validation is completing the paper, which provides insight into the behaviour and the potential of our approach.

  16. Simulation of 3D parachute fluid–structure interaction based on nonlinear finite element method and preconditioning finite volume method

    Directory of Open Access Journals (Sweden)

    Fan Yuxin

    2014-12-01

    Full Text Available A fluid–structure interaction method combining a nonlinear finite element algorithm with a preconditioning finite volume method is proposed in this paper to simulate parachute transient dynamics. This method uses a three-dimensional membrane–cable fabric model to represent a parachute system at a highly folded configuration. The large shape change during parachute inflation is computed by the nonlinear Newton–Raphson iteration and the linear system equation is solved by the generalized minimal residual (GMRES method. A membrane wrinkling algorithm is also utilized to evaluate the special uniaxial tension state of membrane elements on the parachute canopy. In order to avoid large time expenses during structural nonlinear iteration, the implicit Hilber–Hughes–Taylor (HHT time integration method is employed. For the fluid dynamic simulations, the Roe and HLLC (Harten–Lax–van Leer contact scheme has been modified and extended to compute flow problems at all speeds. The lower–upper symmetric Gauss–Seidel (LU-SGS approximate factorization is applied to accelerate the numerical convergence speed. Finally, the test model of a highly folded C-9 parachute is simulated at a prescribed speed and the results show similar characteristics compared with experimental results and previous literature.

  17. Association of anorectal dose-volume histograms and impaired fecal continence after 3D conformal radiotherapy for carcinoma of the prostate

    International Nuclear Information System (INIS)

    Vordermark, Dirk; Schwab, Michael; Ness-Dourdoumas, Rhea; Sailer, Marco; Flentje, Michael; Koelbl, Oliver

    2003-01-01

    Purpose: The late toxicity of fecal incontinence after pelvic radiotherapy is now frequently recognized but the etiology poorly understood. We therefore investigated associations between dose-volume histogram (DVH) parameters of the rectum and the anal canal with fecal continence as measured by an established 10-item questionnaire. Methods and materials: Forty-four patients treated for carcinoma of the prostate with 58-72 Gy of 3D conformal radiotherapy between 1995 and 1999 who completed the questionnaire formed the study population. Total continence scores of treated patients obtained 1.5 years (median) after radiotherapy were compared to a control group of 30 patients before radiotherapy. Median, mean, minimum and maximum doses as well as the volume (% and ml) treated to 40, 50, 60 and 70 Gy were determined separately for anal canal and rectum. DVH parameters were correlated with total continence score (Spearman rank test) and patients grouped according to observed continence were compared regarding DVH values (Mann-Whitney U-test). Results: Median fecal continence scores were significantly worse in the irradiated than in the control group (31 vs. 35 of a maximum 36 points). In treated patients, 59%/27%/14% were classified as fully continent, slightly incontinent and severely incontinent. Continence was similar in the 58-to-62-Gy, 66-Gy and 68-to-72-Gy dose groups. No DVH parameter was significantly correlated with total continence score, but severely incontinent patients had a significantly higher minimum dose to the anal canal than fully continent/slightly incontinent, accompanied by portals extending significantly further inferiorly with respect to the ischial tuberosities. Conclusions: Excluding the inferior part of the anal canal from the treated volume in 3D conformal therapy for carcinoma of the prostate appears to be a promising strategy to prevent radiation-induced fecal incontinence

  18. 3D neuromelanin-sensitive magnetic resonance imaging with semi-automated volume measurement of the substantia nigra pars compacta for diagnosis of Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Ogisu, Kimihiro; Shirato, Hiroki [Hokkaido University Graduate School of Medicine, Department of Radiology, Hokkaido (Japan); Kudo, Kohsuke; Sasaki, Makoto [Iwate Medical University, Division of Ultrahigh Field MRI, Iwate (Japan); Sakushima, Ken; Yabe, Ichiro; Sasaki, Hidenao [Hokkaido University Hospital, Department of Neurology, Hokkaido (Japan); Terae, Satoshi; Nakanishi, Mitsuhiro [Hokkaido University Hospital, Department of Radiology, Hokkaido (Japan)

    2013-06-15

    Neuromelanin-sensitive MRI has been reported to be used in the diagnosis of Parkinson's disease (PD), which results from loss of dopamine-producing cells in the substantia nigra pars compacta (SNc). In this study, we aimed to apply a 3D turbo field echo (TFE) sequence for neuromelanin-sensitive MRI and to evaluate the diagnostic performance of semi-automated method for measurement of SNc volume in patients with PD. We examined 18 PD patients and 27 healthy volunteers (control subjects). A 3D TFE technique with off-resonance magnetization transfer pulse was used for neuromelanin-sensitive MRI on a 3T scanner. The SNc volume was semi-automatically measured using a region-growing technique at various thresholds (ranging from 1.66 to 2.48), with the signals measured relative to that for the superior cerebellar peduncle. Receiver operating characteristic (ROC) analysis was performed at all thresholds. Intra-rater reproducibility was evaluated by intraclass correlation coefficient (ICC). The average SNc volume in the PD group was significantly smaller than that in the control group at all the thresholds (P < 0.01, student t test). At higher thresholds (>2.0), the area under the curve of ROC (Az) increased (0.88). In addition, we observed balanced sensitivity and specificity (0.83 and 0.85, respectively). At lower thresholds, sensitivity tended to increase but specificity reduced in comparison with that at higher thresholds. ICC was larger than 0.9 when the threshold was over 1.86. Our method can distinguish the PD group from the control group with high sensitivity and specificity, especially for early stage of PD. (orig.)

  19. Analysis of information for cerebrovascular disorders obtained by 3D MR imaging

    International Nuclear Information System (INIS)

    Yoshikawa, Kohki; Yoshioka, Naoki; Watanabe, Fumio; Shiono, Takahiro; Sugishita, Morihiro; Umino, Kazunori.

    1995-01-01

    Recently, it becomes easy to analyze information obtained by 3D MR imaging due to remarkable progress of fast MR imaging technique and analysis tool. Six patients suffered from aphasia (4 cerebral infarctions and 2 bleedings) were performed 3D MR imaging (3D FLASH-TR/TE/flip angle; 20-50 msec/6-10 msec/20-30 degrees) and their volume information were analyzed by multiple projection reconstruction (MPR), surface rendering 3D reconstruction, and volume rendering 3D reconstruction using Volume Design PRO (Medical Design Co., Ltd.). Four of them were diagnosed as Broca's aphasia clinically and their lesions could be detected around the cortices of the left inferior frontal gyrus. Another 2 patients were diagnosed as Wernicke's aphasia and the lesions could be detected around the cortices of the left supramarginal gyrus. This technique for 3D volume analyses would provide quite exact locational information about cerebral cortical lesions. (author)

  20. Analysis of information for cerebrovascular disorders obtained by 3D MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kohki [Tokyo Univ. (Japan). Inst. of Medical Science; Yoshioka, Naoki; Watanabe, Fumio; Shiono, Takahiro; Sugishita, Morihiro; Umino, Kazunori

    1995-12-01

    Recently, it becomes easy to analyze information obtained by 3D MR imaging due to remarkable progress of fast MR imaging technique and analysis tool. Six patients suffered from aphasia (4 cerebral infarctions and 2 bleedings) were performed 3D MR imaging (3D FLASH-TR/TE/flip angle; 20-50 msec/6-10 msec/20-30 degrees) and their volume information were analyzed by multiple projection reconstruction (MPR), surface rendering 3D reconstruction, and volume rendering 3D reconstruction using Volume Design PRO (Medical Design Co., Ltd.). Four of them were diagnosed as Broca`s aphasia clinically and their lesions could be detected around the cortices of the left inferior frontal gyrus. Another 2 patients were diagnosed as Wernicke`s aphasia and the lesions could be detected around the cortices of the left supramarginal gyrus. This technique for 3D volume analyses would provide quite exact locational information about cerebral cortical lesions. (author).

  1. 3D-segmentation of the 18F-choline PET signal for target volume definition in radiation therapy of the prostate.

    Science.gov (United States)

    Ciernik, I Frank; Brown, Derek W; Schmid, Daniel; Hany, Thomas; Egli, Peter; Davis, J Bernard

    2007-02-01

    Volumetric assessment of PET signals becomes increasingly relevant for radiotherapy (RT) planning. Here, we investigate the utility of 18F-choline PET signals to serve as a structure for semi-automatic segmentation for forward treatment planning of prostate cancer. 18F-choline PET and CT scans of ten patients with histologically proven prostate cancer without extracapsular growth were acquired using a combined PET/CT scanner. Target volumes were manually delineated on CT images using standard software. Volumes were also obtained from 18F-choline PET images using an asymmetrical segmentation algorithm. PTVs were derived from CT 18F-choline PET based clinical target volumes (CTVs) by automatic expansion and comparative planning was performed. As a read-out for dose given to non-target structures, dose to the rectal wall was assessed. Planning target volumes (PTVs) derived from CT and 18F-choline PET yielded comparable results. Optimal matching of CT and 18F-choline PET derived volumes in the lateral and cranial-caudal directions was obtained using a background-subtracted signal thresholds of 23.0+/-2.6%. In antero-posterior direction, where adaptation compensating for rectal signal overflow was required, optimal matching was achieved with a threshold of 49.5+/-4.6%. 3D-conformal planning with CT or 18F-choline PET resulted in comparable doses to the rectal wall. Choline PET signals of the prostate provide adequate spatial information amendable to standardized asymmetrical region growing algorithms for PET-based target volume definition for external beam RT.

  2. Evaluation of left atrial function by multidetector computed tomography before left atrial radiofrequency-catheter ablation: Comparison of a manual and automated 3D volume segmentation method

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Florian, E-mail: florian.wolf@meduniwien.ac.a [Department of Radiology, Medical University of Vienna, Vienna (Austria); Ourednicek, Petr [Philips Medical Systems, Prague (Czech Republic); Loewe, Christian [Department of Radiology, Medical University of Vienna, Vienna (Austria); Richter, Bernhard; Goessinger, Heinz David; Gwechenberger, Marianne [Department of Cardiology, Medical University of Vienna, Vienna (Austria); Plank, Christina; Schernthaner, Ruediger Egbert; Toepker, Michael; Lammer, Johannes [Department of Radiology, Medical University of Vienna, Vienna (Austria); Feuchtner, Gudrun M. [Department of Radiology, Innsbruck Medical University, Innsbruck (Austria); Institute of Diagnostic Radiology, University Hospital Zurich (Switzerland)

    2010-08-15

    Introduction: The purpose of this study was to compare a manual and automated 3D volume segmentation tool for evaluation of left atrial (LA) function by 64-slice multidetector-CT (MDCT). Methods and materials: In 33 patients with paroxysmal atrial fibrillation a MDCT scan was performed before radiofrequency-catheter ablation. Atrial function (minimal volume (LAmin), maximal volume (LAmax), stroke volume (SV), ejection fraction (EF)) was evaluated by two readers using a manual and an automatic tool and measurement time was evaluated. Results: Automated LA volume segmentation failed in one patient due to low LA enhancement (103HU). Mean LAmax, LAmin, SV and EF were 127.7 ml, 93 ml, 34.7 ml, 27.1% by the automated, and 122.7 ml, 89.9 ml, 32.8 ml, 26.3% by the manual method with no significant difference (p > 0.05) and high Pearsons correlation coefficients (r = 0.94, r = 0.94, r = 0.82 and r = 0.85, p < 0.0001), respectively. The automated method was significantly faster (p < 0.001). Interobserver variability was low for both methods with Pearson's correlation coefficients between 0.98 and 0.99 (p < 0.0001). Conclusions: Evaluation of LA volume and function with 64-slice MDCT is feasible with a very low interobserver variability. The automatic method is as accurate as the manual method but significantly less time consuming permitting a routine use in clinical practice before RF-catheter ablation.

  3. The ATLAS3D project - IX. The merger origin of a fast- and a slow-rotating early-type galaxy revealed with deep optical imaging: first results

    Science.gov (United States)

    Duc, Pierre-Alain; Cuillandre, Jean-Charles; Serra, Paolo; Michel-Dansac, Leo; Ferriere, Etienne; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-10-01

    680 is typical for fast rotators which make the bulk of nearby ETGs in the ATLAS3D sample. On the other hand, NGC 5557 belongs to the poorly populated class of massive, round, slow rotators that are predicted by semi-analytic models and cosmological simulations to be the end-product of a complex mass accretion history, involving ancient major mergers and more recent minor mergers. Our observations suggest that under specific circumstances a single binary merger may dominate the formation history of such objects and thus that at least some massive ETGs may form at relatively low redshift. Whether the two galaxies studied here are representative of their own sub-class of ETGs is still an open question that will be addressed by an on-going deep optical survey of ATLAS3D galaxies.

  4. A Fast and Robust Feature-Based Scan-Matching Method in 3D SLAM and the Effect of Sampling Strategies

    Directory of Open Access Journals (Sweden)

    Cihan Ulas

    2013-11-01

    Full Text Available Simultaneous localization and mapping (SLAM plays an important role in fully autonomous systems when a GNSS (global navigation satellite system is not available. Studies in both 2D indoor and 3D outdoor SLAM are based on the appearance of environments and utilize scan-matching methods to find rigid body transformation parameters between two consecutive scans. In this study, a fast and robust scan-matching method based on feature extraction is introduced. Since the method is based on the matching of certain geometric structures, like plane segments, the outliers and noise in the point cloud are considerably eliminated. Therefore, the proposed scan-matching algorithm is more robust than conventional methods. Besides, the registration time and the number of iterations are significantly reduced, since the number of matching points is efficiently decreased. As a scan-matching framework, an improved version of the normal distribution transform (NDT is used. The probability density functions (PDFs of the reference scan are generated as in the traditional NDT, and the feature extraction - based on stochastic plane detection - is applied to the only input scan. By using experimental dataset belongs to an outdoor environment like a university campus, we obtained satisfactory performance results. Moreover, the feature extraction part of the algorithm is considered as a special sampling strategy for scan-matching and compared to other sampling strategies, such as random sampling and grid-based sampling, the latter of which is first used in the NDT. Thus, this study also shows the effect of the subsampling on the performance of the NDT.

  5. Study of the factors affecting the karst volume assessment in the Dead Sea sinkhole problem using microgravity field analysis and 3-D modeling

    Directory of Open Access Journals (Sweden)

    L. V. Eppelbaum

    2008-11-01

    Full Text Available Thousands of sinkholes have appeared in the Dead Sea (DS coastal area in Israel and Jordan during two last decades. The sinkhole development is recently associated with the buried evaporation karst at the depth of 25–50 m from earth's surface caused by the drop of the DS level at the rate of 0.8–1.0 m/yr. Drop in the Dead Sea level has changed hydrogeological conditions in the subsurface and caused surface to collapse. The pre-existing cavern was detected using microgravity mapping in the Nahal Hever South site where seven sinkholes of 1–2 m diameter had been opened. About 5000 gravity stations were observed in the area of 200×200 m2 by the use of Scintrex CG-3M AutoGrav gravimeter. Besides the conventional set of corrections applied in microgravity investigations, a correction for a strong gravity horizontal gradient (DS Transform Zone negative gravity anomaly influence was inserted. As a result, residual gravity anomaly of –(0.08÷0.14 mGal was revealed. The gravity field analysis was supported by resistivity measurements. We applied the Emigma 7.8 gravity software to create the 3-D physical-geological models of the sinkholes development area. The modeling was confirmed by application of the GSFC program developed especially for 3-D combined gravity-magnetic modeling in complicated environments. Computed numerous gravity models verified an effective applicability of the microgravity technology for detection of karst cavities and estimation of their physical-geological parameters. A volume of the karst was approximately estimated as 35 000 m3. The visual analysis of large sinkhole clusters have been forming at the microgravity anomaly site, confirmed the results of microgravity mapping and 3-D modeling.

  6. An Agent Based Collaborative Simplification of 3D Mesh Model

    Science.gov (United States)

    Wang, Li-Rong; Yu, Bo; Hagiwara, Ichiro

    Large-volume mesh model faces the challenge in fast rendering and transmission by Internet. The current mesh models obtained by using three-dimensional (3D) scanning technology are usually very large in data volume. This paper develops a mobile agent based collaborative environment on the development platform of mobile-C. Communication among distributed agents includes grasping image of visualized mesh model, annotation to grasped image and instant message. Remote and collaborative simplification can be efficiently conducted by Internet.

  7. Large-eddy simulations of 3D Taylor-Green vortex: comparison of Smoothed Particle Hydrodynamics, Lattice Boltzmann and Finite Volume methods

    International Nuclear Information System (INIS)

    Kajzer, A; Pozorski, J; Szewc, K

    2014-01-01

    In the paper we present Large-eddy simulation (LES) results of 3D Taylor- Green vortex obtained by the three different computational approaches: Smoothed Particle Hydrodynamics (SPH), Lattice Boltzmann Method (LBM) and Finite Volume Method (FVM). The Smagorinsky model was chosen as a subgrid-scale closure in LES for all considered methods and a selection of spatial resolutions have been investigated. The SPH and LBM computations have been carried out with the use of the in-house codes executed on GPU and compared, for validation purposes, with the FVM results obtained using the open-source CFD software OpenFOAM. A comparative study in terms of one-point statistics and turbulent energy spectra shows a good agreement of LES results for all methods. An analysis of the GPU code efficiency and implementation difficulties has been made. It is shown that both SPH and LBM may offer a significant advantage over mesh-based CFD methods.

  8. Persistently better treatment planning results of intensity-modulated (IMRT) over conformal radiotherapy (3D-CRT) in prostate cancer patients with significant variation of clinical target volume and/or organs-at-risk

    International Nuclear Information System (INIS)

    Fenoglietto, Pascal; Laliberte, Benoit; Allaw, Ali; Ailleres, Norbert; Idri, Katia; Hay, Meng Huor; Moscardo, Carmen Llacer; Gourgou, Sophie; Dubois, Jean-Bernard; Azria, David

    2008-01-01

    Purpose: To compare the dose coverage of planning and clinical target volume (PTV, CTV), and organs-at-risk (OAR) between intensity-modulated (3D-IMRT) and conventional conformal radiotherapy (3D-CRT) before and after internal organ variation in prostate cancer. Methods and materials: We selected 10 patients with clinically significant interfraction volume changes. Patients were treated with 3D-IMRT to 80 Gy (minimum PTV dose of 76 Gy, excluding rectum). Fictitious, equivalent 3D-CRT plans (80 Gy at isocenter, with 95% isodose (76 Gy) coverage of PTV, with rectal blocking above 76 Gy) were generated using the same planning CT data set ('CT planning'). The plans were then also applied to a verification CT scan ('CT verify') obtained at a different moment. PTV, CTV, and OAR dose coverage were compared using non-parametric tests statistics for V95, V90 (% of the volume receiving ≥95 or 90% of the dose) and D50 (dose to 50% of the volume). Results: Mean V95 of the PTV for 'CT planning' was 94.3% (range, 88-99) vs 89.1% (range, 84-94.5) for 3D-IMRT and 3D-CRT (p = 0.005), respectively. Mean V95 of the CTV for 'CT verify' was 97% for both 3D-IMRT and 3D-CRT. Mean D50 of the rectum for 'CT planning' was 26.8 Gy (range, 22-35) vs 43.5 Gy (range, 33.5-50.5) for 3D-IMRT and 3D-CRT (p = 0.0002), respectively. For 'CT verify', this D50 was 31.1 Gy (range, 16.5-44) vs 44.2 Gy (range, 34-55) for 3D-IMRT and 3D-CRT (p = 0.006), respectively. V95 of the rectum was 0% for both plans for 'CT planning', and 2.3% (3D-IMRT) vs 2.1% (3D-CRT) for 'CT verify' (p = non-sig.). Conclusion: Dose coverage of the PTV and OAR was better with 3D-IMRT for each patient and remained so after internal volume changes

  9. Emphysema quantification on low-dose CT using percentage of low-attenuation volume and size distribution of low-attenuation lung regions: Effects of adaptive iterative dose reduction using 3D processing

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Mizuho, E-mail: nmizuho@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Matsumoto, Sumiaki, E-mail: sumatsu@med.kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Seki, Shinichiro, E-mail: sshin@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Koyama, Hisanobu, E-mail: hkoyama@med.kobe-u.ac.jp [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Fujisawa, Yasuko, E-mail: yasuko1.fujisawa@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); Sugihara, Naoki, E-mail: naoki.sugihara@toshiba.co.jp [Toshiba Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi 324-8550 (Japan); and others

    2014-12-15

    Highlights: • Emphysema quantification (LAV% and D) was affected by image noise on low-dose CT. • For LAV% and D, AIDR 3D improved agreement of quantification on low-dose CT. • AIDR 3D has the potential to quantify emphysema accurately on low-dose CT. - Abstract: Purpose: To evaluate the effects of adaptive iterative dose reduction using 3D processing (AIDR 3D) for quantification of two measures of emphysema: percentage of low-attenuation volume (LAV%) and size distribution of low-attenuation lung regions. Method and materials: : Fifty-two patients who underwent standard-dose (SDCT) and low-dose CT (LDCT) were included. SDCT without AIDR 3D, LDCT without AIDR 3D, and LDCT with AIDR 3D were used for emphysema quantification. First, LAV% was computed at 10 thresholds from −990 to −900 HU. Next, at the same thresholds, linear regression on a log–log plot was used to compute the power law exponent (D) for the cumulative frequency-size distribution of low-attenuation lung regions. Bland–Altman analysis was used to assess whether AIDR 3D improved agreement between LDCT and SDCT for emphysema quantification of LAV% and D. Results: The mean relative differences in LAV% between LDCT without AIDR 3D and SDCT were 3.73%–88.18% and between LDCT with AIDR 3D and SDCT were −6.61% to 0.406%. The mean relative differences in D between LDCT without AIDR 3D and SDCT were 8.22%–19.11% and between LDCT with AIDR 3D and SDCT were 1.82%–4.79%. AIDR 3D improved agreement between LDCT and SDCT at thresholds from −930 to −990 HU for LAV% and at all thresholds for D. Conclusion: AIDR 3D improved the consistency between LDCT and SDCT for emphysema quantification of LAV% and D.

  10. Comparative study between the Spin-echo and 3-D fast imaging techniques in the Knee evaluation with magnetic resonance. Estudio comparativo entre las tecnicas de Spin-Eco ecogradiente 3D, en la evaluacion de la rodilla con resonancia magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Oleaga Zufiria, L.; Ibaez Zubiarrain, A.; Grande Icaran, J.; Vela Martin, A.C.; Cintora Leon, E.; Grau Garcia, M.; Grande Icaran, D. (Hospital Civil de Bilbao. Servicio de Radiodiagnostico. Bilbao (Spain))

    1993-01-01

    We have carried out a retrospective analysis of the results of magnetic resonance (MR) studies in 20 patients, comparing two different sequences. We compared a 2-D spin-echo (SE2D) sequence with a 3-D fast imaging with steady-state precession (FISP3D) sequence in the attempt to compare the reliability of each in the detection of knee injuries. Arthroscopy was employed as a control technique. Our study revealed no statistically significant difference between the two sequences, although the overall sensitivity for the detection of meniscal lesions was slightly greater with the FISP3D sequence; however, the reliability in the detection of ruptures of the posterior cruciate ligament is less with this sequence than with the SE2D sequence. Both sequences showed very low sensitivity in the detection of hyaline cartilage injuries. (Author) 14 refs.

  11. Design and validation of a 3D virtual reality desktop system for sonographic length and volume measurements in early pregnancy evaluation.

    Science.gov (United States)

    Baken, Leonie; van Gruting, Isabelle M A; Steegers, Eric A P; van der Spek, Peter J; Exalto, Niek; Koning, Anton H J

    2015-03-01

    To design and validate a desktop virtual reality (VR) system, for presentation and assessment of volumetric data, based on commercially off-the-shelf hardware as an alternative to a fully immersive CAVE-like I-Space VR system. We designed a desktop VR system, using a three-dimensional (3D) monitor and a six degrees-of-freedom tracking system. A personal computer uses the V-Scope (Erasmus MC, Rotterdam, The Netherlands) volume-rendering application, developed for the I-Space, to create a hologram of volumetric data. Inter- and intraobserver reliability for crown-rump length and embryonic volume measurements are investigated using Bland-Altman plots and intraclass correlation coefficients. Time required for the measurements was recorded. Comparing the I-Space and the desktop VR system, the mean difference for crown-rump length is -0.34% (limits of agreement -2.58-1.89, ±2.24%) and for embryonic volume -0.92% (limits of agreement -6.97-5.13, ±6.05%). Intra- and interobserver intraclass correlation coefficients of the desktop VR system were all >0.99. Measurement times were longer on the desktop VR system compared with the I-Space, but the differences were not statistically significant. A user-friendly desktop VR system can be put together using commercially off-the-shelf hardware at an acceptable price. This system provides a valid and reliable method for embryonic length and volume measurements and can be used in clinical practice. © 2014 Wiley Periodicals, Inc.

  12. SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

    International Nuclear Information System (INIS)

    Soultan, D; Murphy, J; James, C; Hoh, C; Moiseenko, V; Cervino, L; Gill, B

    2015-01-01

    Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images were binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing

  13. 3-D volume rendering visualization for calculated distributions of diesel spray; Diesel funmu kyodo suchi keisan kekka no sanjigen volume rendering hyoji

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizaki, T; Imanishi, H; Nishida, K; Yamashita, H; Hiroyasu, H; Kaneda, K [Hiroshima University, Hiroshima (Japan)

    1997-10-01

    Three dimensional visualization technique based on volume rendering method has been developed in order to translate calculated results of diesel combustion simulation into realistically spray and flame images. This paper presents an overview of diesel combustion model which has been developed at Hiroshima University, a description of the three dimensional visualization technique, and some examples of spray and flame image generated by this visualization technique. 8 refs., 8 figs., 1 tab.

  14. 3D Animation Essentials

    CERN Document Server

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  15. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  16. Advanced 3-D Ultrasound Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Morten Fischer

    The main purpose of the PhD project was to develop methods that increase the 3-D ultrasound imaging quality available for the medical personnel in the clinic. Acquiring a 3-D volume gives the medical doctor the freedom to investigate the measured anatomy in any slice desirable after the scan has...... been completed. This allows for precise measurements of organs dimensions and makes the scan more operator independent. Real-time 3-D ultrasound imaging is still not as widespread in use in the clinics as 2-D imaging. A limiting factor has traditionally been the low image quality achievable using...... a channel limited 2-D transducer array and the conventional 3-D beamforming technique, Parallel Beamforming. The first part of the scientific contributions demonstrate that 3-D synthetic aperture imaging achieves a better image quality than the Parallel Beamforming technique. Data were obtained using both...

  17. Optimal and fast rotational alignment of volumes with missing data in Fourier space.

    Science.gov (United States)

    Shatsky, Maxim; Arbelaez, Pablo; Glaeser, Robert M; Brenner, Steven E

    2013-11-01

    Electron tomography of intact cells has the potential to reveal the entire cellular content at a resolution corresponding to individual macromolecular complexes. Characterization of macromolecular complexes in tomograms is nevertheless an extremely challenging task due to the high level of noise, and due to the limited tilt angle that results in missing data in Fourier space. By identifying particles of the same type and averaging their 3D volumes, it is possible to obtain a structure at a more useful resolution for biological interpretation. Currently, classification and averaging of sub-tomograms is limited by the speed of computational methods that optimize alignment between two sub-tomographic volumes. The alignment optimization is hampered by the fact that the missing data in Fourier space has to be taken into account during the rotational search. A similar problem appears in single particle electron microscopy where the random conical tilt procedure may require averaging of volumes with a missing cone in Fourier space. We present a fast implementation of a method guaranteed to find an optimal rotational alignment that maximizes the constrained cross-correlation function (cCCF) computed over the actual overlap of data in Fourier space. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  18. New portable FELIX 3D display

    Science.gov (United States)

    Langhans, Knut; Bezecny, Daniel; Homann, Dennis; Bahr, Detlef; Vogt, Carsten; Blohm, Christian; Scharschmidt, Karl-Heinz

    1998-04-01

    An improved generation of our 'FELIX 3D Display' is presented. This system is compact, light, modular and easy to transport. The created volumetric images consist of many voxels, which are generated in a half-sphere display volume. In that way a spatial object can be displayed occupying a physical space with height, width and depth. The new FELIX generation uses a screen rotating with 20 revolutions per second. This target screen is mounted by an easy to change mechanism making it possible to use appropriate screens for the specific purpose of the display. An acousto-optic deflection unit with an integrated small diode pumped laser draws the images on the spinning screen. Images can consist of up to 10,000 voxels at a refresh rate of 20 Hz. Currently two different hardware systems are investigated. The first one is based on a standard PCMCIA digital/analog converter card as an interface and is controlled by a notebook. The developed software is provided with a graphical user interface enabling several animation features. The second, new prototype is designed to display images created by standard CAD applications. It includes the development of a new high speed hardware interface suitable for state-of-the- art fast and high resolution scanning devices, which require high data rates. A true 3D volume display as described will complement the broad range of 3D visualization tools, such as volume rendering packages, stereoscopic and virtual reality techniques, which have become widely available in recent years. Potential applications for the FELIX 3D display include imaging in the field so fair traffic control, medical imaging, computer aided design, science as well as entertainment.

  19. 3 T MR 3D fast imaging employing steady state acquisition demonstrating branches of intraparotid facial nerve, parotid duct, and relation with parotid tumors

    International Nuclear Information System (INIS)

    Li Yan; Li Chuanting; Zhang Dongsheng; Ai Bin; Zhang Weidong; Wu Lebin

    2010-01-01

    Objective: To investigate the usefulness of 3 T MRI 3D-FIESTA in the evaluation of the intraparotid components of the facial nerve and parotid duct, and compare them with surgical findings. Methods: Twenty-two cases with parotid benign tumors were scanned with conventional and 3D-FIESTA sequences on 3 T MRI scanner. Postprocessed multiplanar images were obtained with the workstation. Parotid ducts and facial nerves and tumors were identified on these images. The relationship of the tumors to the facial nerves and Parotid ducts was confirmed at surgery. Results: Various types of parotid benign tumors had their characteristics on 3 T MR imaging. Parotid benign tumors mainly showed hypo-intensity on T 1 WI in 21 cases, and hyper-intensity on T 2 WI in 22 cases. But on 3D-FIESTA images, they appeared hypointensity (10 cases) or high intensity (12 cases) due to different types. Facial nerves in parotid appeared as linear structures with hypo-inteusity. The indication of the main trunks were 16 and 18 cases for T 1 WI and T 2 WI images, while on 3D-FIESTA images, the main trunks and cervicofacial and temporofacial divisions of the facial nerves were found in 22, 21,22 cases. Parotid ducts appeared as structures with hypo-intensity on T 1 WI and hyper-intensity on multiplanar images (14, 20, 22 cases). Compared with surgical results, the main trunks of the facial nerve were correctly showed by 3D-FIESTA images in 20 cases. However, in 2 cases they were not located in the operation because of shifting. Conclusion: 3 T MR 3D-FIESTA imaging could depict the extracranial facial nerve and the parotid duct in the parotid gland, which is useful for preoperative evaluation of parotid gland tumors. (authors)

  20. 城市DSM的快速获取及其三维显示的研究%Fast Acquiring Urban DSM Image and Displaying 3D Image

    Institute of Scientific and Technical Information of China (English)

    尤红建; 刘彤; 苏林; 刘少创; 郭冠军; 李树楷

    2001-01-01

    城市数字表面模型(DSM)作为城市的重要信息有着十分广泛的应用,机载三维成像仪可以快速获取DSM数据,而无需地面控制点。该文介绍了利用三维成像仪快速获取城市DSM图像的数据处理技术,阐述了基于城市DSM影像显示城市三维模型的原理,着重分析了显示城市DSM图像奇异表面的方法和侧面处理思想。最后通过珠海、澳门地区飞行数据的处理和三维鸟瞰显示,说明了方法的可行性。%As an important urban information, urban digital surface models(DSM) are widely used in many fields. Airborne 3D imager which is developed by the Institute of Remote Sensing Applications, Chinese Academy of Sciences can acquire DSM in quasi-real-time without any ground control points. The data processing technology to acquire urban DSM by 3D imager is presented in this paper. How to display urban DSM which is different from natural surface in 3D is discussed in detail. An example of data processing and 3D displaying of urban DSM is given at the end. According to the fly test the efficiency of 3D imager is several times higher than that of traditional methods to acquire urban DSM, and the method to display urban DSM in 3D is feasible.

  1. Wobbled splatting-a fast perspective volume rendering method for simulation of x-ray images from CT

    International Nuclear Information System (INIS)

    Birkfellner, Wolfgang; Seemann, Rudolf; Figl, Michael; Hummel, Johann; Ede, Christopher; Homolka, Peter; Yang Xinhui; Niederer, Peter; Bergmann, Helmar

    2005-01-01

    3D/2D registration, the automatic assignment of a global rigid-body transformation matching the coordinate systems of patient and preoperative volume scan using projection images, is an important topic in image-guided therapy and radiation oncology. A crucial part of most 3D/2D registration algorithms is the fast computation of digitally rendered radiographs (DRRs) to be compared iteratively to radiographs or portal images. Since registration is an iterative process, fast generation of DRRs-which are perspective summed voxel renderings-is desired. In this note, we present a simple and rapid method for generation of DRRs based on splat rendering. As opposed to conventional splatting, antialiasing of the resulting images is not achieved by means of computing a discrete point spread function (a so-called footprint), but by stochastic distortion of either the voxel positions in the volume scan or by the simulation of a focal spot of the x-ray tube with non-zero diameter. Our method generates slightly blurred DRRs suitable for registration purposes at framerates of approximately 10 Hz when rendering volume images with a size of 30 MB. (note)

  2. 3D planning and radiation oncology residents' training

    International Nuclear Information System (INIS)

    Jayaraman, Subramania

    1991-01-01

    Radiation treatments in radiation oncology clinics have been always planned to irradiate three dimensional (3D) volumes. Though the term 3D planning has come in vogue only in recent years, the essence of 3D planning had been always there. This is because the patient is a 3D subject and every treatment option adopted in a radiotherapy clinic has to be based on a 3D judgement of its acceptability. An essential aspect of training of radiation oncology residents is to help them understand the different techniques and methods used to get an acceptable 3D dose delivery. The tools of 3D planning should be introduced to the residents for their educational value. The regular use of these tools may require not only fast computers and work stations, but also a change of routine in the department. This might be difficult since the departmental routine can evolve only gradually. On the other hand, an insight about the advantages of the tools could be gained through a simple personal computer. Some examples of using the 3D planning tools through a personal computer, for educational purposes have been presented here, using clinical contexts routinely encountered. (author). 5 refs., 10 figs

  3. Comparison of bone-implant contact and bone-implant volume between 2D-histological sections and 3D-SRµCT slices

    Directory of Open Access Journals (Sweden)

    R Bernhardt

    2012-04-01

    Full Text Available Histological imaging is still considered the gold standard for analysing bone formation around metallic implants. Generally, a limited number of histological sections per sample are used for the approximation of mean values of peri-implant bone formation. In this study we compared statistically the results of bone-implant contact (BIC and bone-implant volume (BIV obtained by histological sections, with those obtained by X-ray absorption images from synchrotron radiation micro-computed tomography (SRµCT using osseointegrated screw-shaped implants from a mini-pig study. Comparing the BIC results of 3-4 histological sections per implant sample with the appropriate 3-4 SRµCT slices showed a non-significant difference of 1.9 % (p = 0.703. The contact area assessed by the whole 3D information from the SRµCT measurement in comparison to the histomorphometric results showed a non-significant difference in BIC of 4.9 % (p = 0.171. The amount of the bone-implant volume in the histological sections and the appropriate SRµCT slices showed a non-significant difference by only 1.4 % (p = 0.736 and also remains non-significant with 2.6 % (p = 0.323 using the volumetric SRµCT information. We conclude that for a clinical evaluation of implant osseointegration with histological imaging at least 3-4 sections per sample are sufficient to represent the BIC or BIV for a sample. Due to the fact that in this study we have found a significant intra-sample variation in BIC of up to ± 35 % the selection of only one or two histological sections per sample may strongly influence the determined BIC.

  4. Properties of Resistive Hydrogen Sensors as a Function of Additives of 3 D-Metals Introduced in the Volume of Thin Nanocrystalline SnO2 Films

    Science.gov (United States)

    Sevast'yanov, E. Yu.; Maksimova, N. K.; Potekaev, A. I.; Sergeichenko, N. V.; Chernikov, E. V.; Almaev, A. V.; Kushnarev, B. O.

    2017-11-01

    Analysis of the results of studying electrical and gas sensitive characteristics of the molecular hydrogen sensors based on thin nanocrystalline SnO2 films coated with dispersed Au layers and containing Au+Ni and Au+Co impurities in the bulk showed that the characteristics of these sensors are more stable under the prolonged exposure to hydrogen in comparison with Au/SnO2:Sb, Au films modified only with gold. It has been found that introduction of the nickel and cobalt additives increases the band bending at the grain boundaries of tin dioxide already in freshly prepared samples, which indicates an increase in the density Ni of the chemisorbed oxygen. It is important that during testing, the band bending eφs at the grain boundaries of tin dioxide additionally slightly increases. It can be assumed that during crystallization of films under thermal annealing, the 3d-metal atoms in the SnO2 volume partially segregate on the surface of microcrystals and form bonds with lattice oxygen, the superstoichiometric tin atoms are formed, and the density Ni increases. If the bonds of oxygen with nickel and cobalt are stronger than those with tin, then, under the prolonged tests, atomic hydrogen will be oxidized not by lattice oxygen, but mainly by the chemisorbed one. In this case, stability of the sensors' characteristics increases.

  5. Volume perfusion CT (VPCT) for the differential diagnosis of patients with suspected cerebral vasospasm: Qualitative and quantitative analysis of 3D parameter maps

    International Nuclear Information System (INIS)

    Dolatowski, K.; Malinova, V.; Frölich, A.M.J.; Schramm, R.; Haberland, U.; Klotz, E.; Mielke, D.; Knauth, M.; Schramm, P.

    2014-01-01

    Object: Cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH) implies high risk for secondary ischemia. It requires early diagnosis to start treatment on time. We aimed to assess the utility of “whole brain” VPCT for detecting localization and characteristics of arterial vasospasm. Methods: 23 patients received a non-enhanced CT, VPCT and CTA of the brain. The distribution of ischemic lesions was analyzed on 3D-perfusion-parameter-maps of CBF, CBV, MTT, TTS, TTP, and TTD. CT-angiographic axial and coronal maximum-intensity-projections were reconstructed to determine arterial vasospasm. CT-data was compared to DSA, if performed additionally. Volume-of-interest placement was used to obtain quantitative mean VPCT values. Results: 82% patients (n = 19) had focal cerebral hypoperfusion. 100% sensitivity and 100% specificity was found for TTS (median 1.9 s), MTT (median 5.9 s) and TTD (median 7.6 s). CBV showed no significant differences. In 78% (n = 18) focal vessel aberrations could be detected either on CTA or DSA or on both. Conclusion: VPCT is a non-invasive method with the ability to detect focal perfusion deficits almost in the whole brain. While DSA remains to be the gold standard for detection of CV, VPCT has the potential to improve noninvasive diagnosis and treatment decisions

  6. EUROPEANA AND 3D

    Directory of Open Access Journals (Sweden)

    D. Pletinckx

    2012-09-01

    Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  7. The ATLAS3D project - I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria

    Science.gov (United States)

    Cappellari, Michele; Emsellem, Eric; Krajnović, Davor; McDermid, Richard M.; Scott, Nicholas; Verdoes Kleijn, G. A.; Young, Lisa M.; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Khochfar, Sadegh; Kuntschner, Harald; Lablanche, Pierre-Yves; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Serra, Paolo; Weijmans, Anne-Marie

    2011-05-01

    The ATLAS3D project is a multiwavelength survey combined with a theoretical modelling effort. The observations span from the radio to the millimetre and optical, and provide multicolour imaging, two-dimensional kinematics of the atomic (H I), molecular (CO) and ionized gas (Hβ, [O III] and [N I]), together with the kinematics and population of the stars (Hβ, Fe5015 and Mg b), for a carefully selected, volume-limited (1.16 × 105 Mpc3) sample of 260 early-type (elliptical E and lenticular S0) galaxies (ETGs). The models include semi-analytic, N-body binary mergers and cosmological simulations of galaxy formation. Here we present the science goals for the project and introduce the galaxy sample and the selection criteria. The sample consists of nearby (D 15°) morphologically selected ETGs extracted from a parent sample of 871 galaxies (8 per cent E, 22 per cent S0 and 70 per cent spirals) brighter than MK statistically representative of the nearby galaxy population. We present the size-luminosity relation for the spirals and ETGs and show that the ETGs in the ATLAS3D sample define a tight red sequence in a colour-magnitude diagram, with few objects in the transition from the blue cloud. We describe the strategy of the SAURON integral field observations and the extraction of the stellar kinematics with the pPXF method. We find typical 1σ errors of ΔV≈ 6 km s-1, Δσ≈ 7 km s-1, Δh3≈Δh4≈ 0.03 in the mean velocity, the velocity dispersion and Gauss-Hermite (GH) moments for galaxies with effective dispersion σe≳ 120 km s-1. For galaxies with lower σe (≈40 per cent of the sample) the GH moments are gradually penalized by pPXF towards zero to suppress the noise produced by the spectral undersampling and only V and σ can be measured. We give an overview of the characteristics of the other main data sets already available for our sample and of the ongoing modelling projects.

  8. Fast, multiphase volume adaptation to hyperosmotic shock by Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Teuta Pilizota

    Full Text Available All living cells employ an array of different mechanisms to help them survive changes in extra cellular osmotic pressure. The difference in the concentration of chemicals in a bacterium's cytoplasm and the external environment generates an osmotic pressure that inflates the cell. It is thought that the bacterium Escherichia coli use a number of interconnected systems to adapt to changes in external pressure, allowing them to maintain turgor and live in surroundings that range more than two-hundred-fold in external osmolality. Here, we use fluorescence imaging to make the first measurements of cell volume changes over time during hyperosmotic shock and subsequent adaptation on a single cell level in vivo with a time resolution on the order of seconds. We directly observe two previously unseen phases of the cytoplasmic water efflux upon hyperosmotic shock. Furthermore, we monitor cell volume changes during the post-shock recovery and observe a two-phase response that depends on the shock magnitude. The initial phase of recovery is fast, on the order of 15-20 min and shows little cell-to-cell variation. For large sucrose shocks, a secondary phase that lasts several hours adds to the recovery. We find that cells are able to recover fully from shocks as high as 1 Osmol/kg using existing systems, but that for larger shocks, protein synthesis is required for full recovery.

  9. 3D Characterization of Recrystallization Boundaries

    DEFF Research Database (Denmark)

    Zhang, Yubin; Godfrey, Andrew William; MacDonald, A. Nicole

    2016-01-01

    A three-dimensional (3D) volume containing a recrystallizing grain and a deformed matrix in a partially recrystallized pure aluminum was characterized using the 3D electron backscattering diffraction technique. The 3D shape of a recrystallizing boundary, separating the recrystallizing grain...... on the formation of protrusions/retrusions....

  10. 3D Integration for Wireless Multimedia

    Science.gov (United States)

    Kimmich, Georg

    The convergence of mobile phone, internet, mapping, gaming and office automation tools with high quality video and still imaging capture capability is becoming a strong market trend for portable devices. High-density video encode and decode, 3D graphics for gaming, increased application-software complexity and ultra-high-bandwidth 4G modem technologies are driving the CPU performance and memory bandwidth requirements close to the PC segment. These portable multimedia devices are battery operated, which requires the deployment of new low-power-optimized silicon process technologies and ultra-low-power design techniques at system, architecture and device level. Mobile devices also need to comply with stringent silicon-area and package-volume constraints. As for all consumer devices, low production cost and fast time-to-volume production is key for success. This chapter shows how 3D architectures can bring a possible breakthrough to meet the conflicting power, performance and area constraints. Multiple 3D die-stacking partitioning strategies are described and analyzed on their potential to improve the overall system power, performance and cost for specific application scenarios. Requirements and maturity of the basic process-technology bricks including through-silicon via (TSV) and die-to-die attachment techniques are reviewed. Finally, we highlight new challenges which will arise with 3D stacking and an outlook on how they may be addressed: Higher power density will require thermal design considerations, new EDA tools will need to be developed to cope with the integration of heterogeneous technologies and to guarantee signal and power integrity across the die stack. The silicon/wafer test strategies have to be adapted to handle high-density IO arrays, ultra-thin wafers and provide built-in self-test of attached memories. New standards and business models have to be developed to allow cost-efficient assembly and testing of devices from different silicon and technology

  11. A fully automatic, threshold-based segmentation method for the estimation of the Metabolic Tumor Volume from PET images: validation on 3D printed anthropomorphic oncological lesions

    Science.gov (United States)

    Gallivanone, F.; Interlenghi, M.; Canervari, C.; Castiglioni, I.

    2016-01-01

    18F-Fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) is a standard functional diagnostic technique to in vivo image cancer. Different quantitative paramters can be extracted from PET images and used as in vivo cancer biomarkers. Between PET biomarkers Metabolic Tumor Volume (MTV) has gained an important role in particular considering the development of patient-personalized radiotherapy treatment for non-homogeneous dose delivery. Different imaging processing methods have been developed to define MTV. The different proposed PET segmentation strategies were validated in ideal condition (e.g. in spherical objects with uniform radioactivity concentration), while the majority of cancer lesions doesn't fulfill these requirements. In this context, this work has a twofold objective: 1) to implement and optimize a fully automatic, threshold-based segmentation method for the estimation of MTV, feasible in clinical practice 2) to develop a strategy to obtain anthropomorphic phantoms, including non-spherical and non-uniform objects, miming realistic oncological patient conditions. The developed PET segmentation algorithm combines an automatic threshold-based algorithm for the definition of MTV and a k-means clustering algorithm for the estimation of the background. The method is based on parameters always available in clinical studies and was calibrated using NEMA IQ Phantom. Validation of the method was performed both in ideal (e.g. in spherical objects with uniform radioactivity concentration) and non-ideal (e.g. in non-spherical objects with a non-uniform radioactivity concentration) conditions. The strategy to obtain a phantom with synthetic realistic lesions (e.g. with irregular shape and a non-homogeneous uptake) consisted into the combined use of standard anthropomorphic phantoms commercially and irregular molds generated using 3D printer technology and filled with a radioactive chromatic alginate. The proposed segmentation algorithm was feasible in a

  12. Microfocal X-ray computed tomography post-processing operations for optimizing reconstruction volumes of stented arteries during 3D computational fluid dynamics modeling.

    Science.gov (United States)

    Ladisa, John F; Olson, Lars E; Ropella, Kristina M; Molthen, Robert C; Haworth, Steven T; Kersten, Judy R; Warltier, David C; Pagel, Paul S

    2005-08-01

    Restenosis caused by neointimal hyperplasia (NH) remains an important clinical problem after stent implantation. Restenosis varies with stent geometry, and idealized computational fluid dynamics (CFD) models have indicated that geometric properties of the implanted stent may differentially influence NH. However, 3D studies capturing the in vivo flow domain within stented vessels have not been conducted at a resolution sufficient to detect subtle alterations in vascular geometry caused by the stent and the subsequent temporal development of NH. We present the details and limitations of a series of post-processing operations used in conjunction with microfocal X-ray CT imaging and reconstruction to generate geometrically accurate flow domains within the localized region of a stent several weeks after implantation. Microfocal X-ray CT reconstruction volumes were subjected to an automated program to perform arterial thresholding, spatial orientation, and surface smoothing of stented and unstented rabbit iliac arteries several weeks after antegrade implantation. A transfer function was obtained for the current post-processing methodology containing reconstructed 16 mm stents implanted into rabbit iliac arteries for up to 21 days after implantation and resolved at circumferential and axial resolutions of 32 and 50 microm, respectively. The results indicate that the techniques presented are sufficient to resolve distributions of WSS with 80% accuracy in segments containing 16 surface perturbations over a 16 mm stented region. These methods will be used to test the hypothesis that reductions in normalized wall shear stress (WSS) and increases in the spatial disparity of WSS immediately after stent implantation may spatially correlate with the temporal development of NH within the stented region.

  13. Open 3D Projects

    Directory of Open Access Journals (Sweden)

    Felician ALECU

    2010-01-01

    Full Text Available Many professionals and 3D artists consider Blender as being the best open source solution for 3D computer graphics. The main features are related to modeling, rendering, shading, imaging, compositing, animation, physics and particles and realtime 3D/game creation.

  14. A direct Arbitrary-Lagrangian-Eulerian ADER-WENO finite volume scheme on unstructured tetrahedral meshes for conservative and non-conservative hyperbolic systems in 3D

    Science.gov (United States)

    Boscheri, Walter; Dumbser, Michael

    2014-10-01

    In this paper we present a new family of high order accurate Arbitrary-Lagrangian-Eulerian (ALE) one-step ADER-WENO finite volume schemes for the solution of nonlinear systems of conservative and non-conservative hyperbolic partial differential equations with stiff source terms on moving tetrahedral meshes in three space dimensions. A WENO reconstruction technique is used to achieve high order of accuracy in space, while an element-local space-time Discontinuous Galerkin finite element predictor on moving curved meshes is used to obtain a high order accurate one-step time discretization. Within the space-time predictor the physical element is mapped onto a reference element using a high order isoparametric approach, where the space-time basis and test functions are given by the Lagrange interpolation polynomials passing through a predefined set of space-time nodes. Since our algorithm is cell-centered, the final mesh motion is computed by using a suitable node solver algorithm. A rezoning step as well as a flattener strategy are used in some of the test problems to avoid mesh tangling or excessive element deformations that may occur when the computation involves strong shocks or shear waves. The ALE algorithm presented in this article belongs to the so-called direct ALE methods because the final Lagrangian finite volume scheme is based directly on a space-time conservation formulation of the governing PDE system, with the rezoned geometry taken already into account during the computation of the fluxes. We apply our new high order unstructured ALE schemes to the 3D Euler equations of compressible gas dynamics, for which a set of classical numerical test problems has been solved and for which convergence rates up to sixth order of accuracy in space and time have been obtained. We furthermore consider the equations of classical ideal magnetohydrodynamics (MHD) as well as the non-conservative seven-equation Baer-Nunziato model of compressible multi-phase flows with

  15. TU-H-CAMPUS-TeP1-05: Fast Processed 3D Printing-Aided Urethane Resin (PUR) Bolus in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, B; Chiu, T; Gu, X; Lee, H; Nedzi, L; Jiang, S [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: 3D printed custom bolus is regularly used in radiation therapy clinic as a compensator. However, usual method of bolus printing with 100% filling is very time-consuming. The purpose of this study is to evaluate the feasibility and benefit of 3D printed bolus filled with UR. Methods: Two boluses were designed on nose (9e electrons) and ear (6× photons) for a head phantom in treatment planning system (TPS) to achieve dose coverage to the skin. The bolus structures (56–167cc) were converted to STereoLithographic (STL) model using an in-house developed algorithm and sent to a commercial fused deposition modeling (FDM) printer. Only shells were printed with polylactic acid (PLA) material. Liquid UR was then placed in a vacuum pump and slowly poured into the hollow bolus from its top opening. Liquid UR hardened in around half an hour. The phantom was rescanned with custom boluses attached and the dosimetry was compared with original design in TPS. Basic CT and dose properties were investigated. GaF films were irradiated to measure dose profile and output of several open photon and electron beams under solid water and UR slabs of same thicknesses. Results: CT number was 11.2±7.3 and 65.4±7.8, respectively for solid water(∼1.04g/cc) and UR(∼1.08g/cc). The output measurement at dmax for 6× was within 2% for the two materials. The relative dose profiles of the two materials above dmax show 94–99% Gamma analysis passing rates for both photons and electrons. Dose distributions with 3D PUR boluses maintained great coverage on the intended skin regions and resembled that with computer generated boluses. Manufacturing 3D PUR boluses was 3–4 times faster than 100% printed boluses. The efficiency significantly improves for larger boluses. Conclusion: The study suggests UR has similar dose responses as solid water. Making custom bolus with UR greatly increases clinical workflow efficiency.

  16. TU-H-CAMPUS-TeP1-05: Fast Processed 3D Printing-Aided Urethane Resin (PUR) Bolus in Radiation Therapy

    International Nuclear Information System (INIS)

    Zhao, B; Chiu, T; Gu, X; Lee, H; Nedzi, L; Jiang, S

    2016-01-01

    Purpose: 3D printed custom bolus is regularly used in radiation therapy clinic as a compensator. However, usual method of bolus printing with 100% filling is very time-consuming. The purpose of this study is to evaluate the feasibility and benefit of 3D printed bolus filled with UR. Methods: Two boluses were designed on nose (9e electrons) and ear (6× photons) for a head phantom in treatment planning system (TPS) to achieve dose coverage to the skin. The bolus structures (56–167cc) were converted to STereoLithographic (STL) model using an in-house developed algorithm and sent to a commercial fused deposition modeling (FDM) printer. Only shells were printed with polylactic acid (PLA) material. Liquid UR was then placed in a vacuum pump and slowly poured into the hollow bolus from its top opening. Liquid UR hardened in around half an hour. The phantom was rescanned with custom boluses attached and the dosimetry was compared with original design in TPS. Basic CT and dose properties were investigated. GaF films were irradiated to measure dose profile and output of several open photon and electron beams under solid water and UR slabs of same thicknesses. Results: CT number was 11.2±7.3 and 65.4±7.8, respectively for solid water(∼1.04g/cc) and UR(∼1.08g/cc). The output measurement at dmax for 6× was within 2% for the two materials. The relative dose profiles of the two materials above dmax show 94–99% Gamma analysis passing rates for both photons and electrons. Dose distributions with 3D PUR boluses maintained great coverage on the intended skin regions and resembled that with computer generated boluses. Manufacturing 3D PUR boluses was 3–4 times faster than 100% printed boluses. The efficiency significantly improves for larger boluses. Conclusion: The study suggests UR has similar dose responses as solid water. Making custom bolus with UR greatly increases clinical workflow efficiency.

  17. Collaborative Project. 3D Radiative Transfer Parameterization Over Mountains/Snow for High-Resolution Climate Models. Fast physics and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Kuo-Nan [Univ. of California, Los Angeles, CA (United States)

    2016-02-09

    Under the support of the aforementioned DOE Grant, we have made two fundamental contributions to atmospheric and climate sciences: (1) Develop an efficient 3-D radiative transfer parameterization for application to intense and intricate inhomogeneous mountain/snow regions. (2) Innovate a stochastic parameterization for light absorption by internally mixed black carbon and dust particles in snow grains for understanding and physical insight into snow albedo reduction in climate models. With reference to item (1), we divided solar fluxes reaching mountain surfaces into five components: direct and diffuse fluxes, direct- and diffuse-reflected fluxes, and coupled mountain-mountain flux. “Exact” 3D Monte Carlo photon tracing computations can then be performed for these solar flux components to compare with those calculated from the conventional plane-parallel (PP) radiative transfer program readily available in climate models. Subsequently, Parameterizations of the deviations of 3D from PP results for five flux components are carried out by means of the multiple linear regression analysis associated with topographic information, including elevation, solar incident angle, sky view factor, and terrain configuration factor. We derived five regression equations with high statistical correlations for flux deviations and successfully incorporated this efficient parameterization into WRF model, which was used as the testbed in connection with the Fu-Liou-Gu PP radiation scheme that has been included in the WRF physics package. Incorporating this 3D parameterization program, we conducted simulations of WRF and CCSM4 to understand and evaluate the mountain/snow effect on snow albedo reduction during seasonal transition and the interannual variability for snowmelt, cloud cover, and precipitation over the Western United States presented in the final report. With reference to item (2), we developed in our previous research a geometric-optics surface-wave approach (GOS) for the

  18. Computerized diagnostic data analysis and 3-D visualization

    International Nuclear Information System (INIS)

    Schuhmann, D.; Haubner, M.; Krapichler, C.; Englmeier, K.H.; Seemann, M.; Schoepf, U.J.; Gebicke, K.; Reiser, M.

    1998-01-01

    Purpose: To survey methods for 3D data visualization and image analysis which can be used for computer based diagnostics. Material and methods: The methods available are explained in short terms and links to the literature are presented. Methods which allow basic manipulation of 3D data are windowing, rotation and clipping. More complex methods for visualization of 3D data are multiplanar reformation, volume projections (MIP, semi-transparent projections) and surface projections. Methods for image analysis comprise local data transformation (e.g. filtering) and definition and application of complex models (e.g. deformable models). Results: Volume projections produce an impression of the 3D data set without reducing the data amount. This supports the interpretation of the 3D data set and saves time in comparison to any investigation which requires examination of all slice images. More advanced techniques for visualization, e.g. surface projections and hybrid rendering visualize anatomical information to a very detailed extent, but both techniques require the segmentation of the structures of interest. Image analysis methods can be used to extract these structures (e.g. an organ) from the image data. Discussion: At the present time volume projections are robust and fast enough to be used routinely. Surface projections can be used to visualize complex and presegmented anatomical features. (orig.) [de

  19. Comparisons of dose-volume histograms for proton-beam versus 3-D conformal X-ray therapy in patients with stage I non-small cell lung cancer

    International Nuclear Information System (INIS)

    Wang, Changlu; Nakayama, Hidetsugu; Sugahara, Shinji; Sakae, Takeji; Tokuuye, Koichi

    2009-01-01

    Dose-volume histograms (DVHs) were reviewed to determine if there is an advantage of the two modalities when treating patients with non-small cell lung cancer (NSCLC). 24 stage I NSCLC patients who underwent proton-beam therapy (PBT) from June 2003 to May 2007 were included in this study. Based on the same clinical target volumes (CTVs), treatment planning was made to cover CTV within 90% isodose lines. Each patient was evaluated by two sets of DVHs, one for PBT and the other for three-dimensional conformal X-ray therapy (3D-CRT). For all patients, the 95% isodose line covered 86.4% of the CTV for PBT, and 43.2% for 3D-CRT. PBT was associated with significantly lower mean doses to the ipsilateral lung, total lung, heart, esophagus, and spinal cord than 3D-CRT. PBT offered reduced radiation doses to the lung when evaluated in terms of percentage lung volumes receiving ≥ 5 Gy (V 5 ), ≥ 10 Gy (V 10 ), and ≥ 20 Gy (V 20 ) when compared to 3D-CRT. PBT is advantageous over 3D-CRT in reducing doses to the lung, heart, esophagus, and spinal cord in treating stage I NSCLC. (orig.)

  20. Feasibility and performance of novel software to quantify metabolically active volumes and 3D partial volume corrected SUV and metabolic volumetric products of spinal bone marrow metastases on 18F-FDG-PET/CT.

    Science.gov (United States)

    Torigian, Drew A; Lopez, Rosa Fernandez; Alapati, Sridevi; Bodapati, Geetha; Hofheinz, Frank; van den Hoff, Joerg; Saboury, Babak; Alavi, Abass

    2011-01-01

    Our aim was to assess feasibility and performance of novel semi-automated image analysis software called ROVER to quantify metabolically active volume (MAV), maximum standardized uptake value-maximum (SUV(max)), 3D partial volume corrected mean SUV (cSUV(mean)), and 3D partial volume corrected mean MVP (cMVP(mean)) of spinal bone marrow metastases on fluorine-18 fluorodeoxyglucose-positron emission tomography/computerized tomography ((18)F-FDG-PET/CT). We retrospectively studied 16 subjects with 31 spinal metastases on FDG-PET/CT and MRI. Manual and ROVER determinations of lesional MAV and SUV(max), and repeated ROVER measurements of MAV, SUV(max), cSUV(mean) and cMVP(mean) were made. Bland-Altman and correlation analyses were performed to assess reproducibility and agreement. Our results showed that analyses of repeated ROVER measurements revealed MAV mean difference (D)=-0.03±0.53cc (95% CI(-0.22, 0.16)), lower limit of agreement (LLOA)=-1.07cc, and upper limit of agreement (ULOA)=1.01cc; SUV(max) D=0.00±0.00 with LOAs=0.00; cSUV(mean) D=-0.01±0.39 (95% CI(-0.15, 0.13)), LLOA=-0.76, and ULOA=0.75; cMVP(mean) D=-0.52±4.78cc (95% CI(-2.23, 1.23)), LLOA=-9.89cc, and ULOA=8.86cc. Comparisons between ROVER and manual measurements revealed volume D= -0.39±1.37cc (95% CI (-0.89, 0.11)), LLOA=-3.08cc, and ULOA=2.30cc; SUV(max) D=0.00±0.00 with LOAs=0.00. Mean percent increase in lesional SUV(mean) and MVP(mean) following partial volume correction using ROVER was 84.25±36.00% and 84.45±35.94% , respectively. In conclusion, it is feasible to estimate MAV, SUV(max), cSUV(mean), and cMVP(mean) of spinal bone marrow metastases from (18)F-FDG-PET/CT quickly and easily with good reproducibility via ROVER software. Partial volume correction is imperative, as uncorrected SUV(mean) and MVP(mean) are significantly underestimated, even for large lesions. This novel approach has great potential for practical, accurate, and precise combined structural-functional PET

  1. View-based 3-D object retrieval

    CERN Document Server

    Gao, Yue

    2014-01-01

    Content-based 3-D object retrieval has attracted extensive attention recently and has applications in a variety of fields, such as, computer-aided design, tele-medicine,mobile multimedia, virtual reality, and entertainment. The development of efficient and effective content-based 3-D object retrieval techniques has enabled the use of fast 3-D reconstruction and model design. Recent technical progress, such as the development of camera technologies, has made it possible to capture the views of 3-D objects. As a result, view-based 3-D object retrieval has become an essential but challenging res

  2. The ATLAS3D project - VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within ΛCDM

    NARCIS (Netherlands)

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frédéric; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Λcold dark matter (ΛCDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via λR. Within

  3. The ATLAS(3D) project : VIII. Modelling the formation and evolution of fast and slow rotator early-type galaxies within lambda CDM

    NARCIS (Netherlands)

    Khochfar, Sadegh; Emsellem, Eric; Serra, Paolo; Bois, Maxime; Alatalo, Katherine; Bacon, R.; Blitz, Leo; Bournaud, Frederic; Bureau, M.; Cappellari, Michele; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Krajnovic, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M.; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Weijmans, Anne-Marie; Young, Lisa M.

    2011-01-01

    We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical Lambda cold dark matter (Lambda CDM) scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed

  4. Parotid gland tumors: A comparison of postoperative radiotherapy techniques using three dimensional (3D) dose distributions and dose-volume histograms (DVHs)

    International Nuclear Information System (INIS)

    Yaparpalvi, Ravindra; Fontenla, Doracy P.; Tyerech, Sangeeta K.; Boselli, Lucia R.; Beitler, Jonathan J.

    1998-01-01

    Purpose: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Methods and Materials: The CT-scans of a representative parotid patient were used. The field size was 9 x 11 cm, the separation was 15.5 cm, and the prescription depth was 4.5 cm. Using 3D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and dose-volume histogram (DVH), nine treatment techniques were compared. [1] unilateral 6 MV photons [2] unilateral 12 MeV electrons [3] unilateral 16 MeV electrons [4] an ipsilateral wedge pair technique using 6 MV photons [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting) [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting) [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting) [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥ 30% of the prescribed dose was 100% for techniques [1], [8] and [9], and < 5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1], [8] and [9] contributed to ≥ 50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed electron-photon beams [8] and [9] are not recommended treatment techniques for unilateral parotid irradiation because of high doses delivered to the

  5. The effect of pre-anaesthetic fasting time and type of food on gastric content volume and acidity in dogs.

    Science.gov (United States)

    Savvas, Ioannis; Rallis, Timoleon; Raptopoulos, Dimitris

    2009-11-01

    To investigate the effect of pre-anaesthetic fasting time and variety of food on gastric content (GC) volume and pH in dogs. Randomized, cross-over, prospective experimental study. Fifteen mongrel dogs (nine females and six males 1-4 years old, weighing 10-24.5 kg). Each dog received the same seven treatments in random order: dry food 3 hours before anaesthesia (BA) (treatment 3D), canned food (half daily rate) 3 hours BA (treatment 3C), 0% fat cow milk 3 hours BA (treatment 3M), dry food 10 hours BA (treatment 10D), canned food 10 hours BA (treatment 10C), low fat canned food 10 hours BA (treatment 10F) and low protein canned food 10 hours BA (treatment 10P). All animals were pre-medicated with propionyl promazine and anaesthesia was induced with thiopental sodium and maintained with halothane. GC was aspirated using an orogastric catheter and its volume and pH were measured. Treatment 10F had significantly lower GC pH than all the 3-hour treatments. Treatments 10D and 10P had significantly lower pH than treatments 3D and 3C. Treatment 3M had significantly lower pH than the other 3-hour treatments. Treatment 3D had significantly greater gastric volume than treatments 3M, 10C, 10F and 10P. Canned food at half the daily rate administered 3 hours before anaesthesia did not increase significantly the GC volume compared to the other types of food used. The GC pH was also high. This type of food fed 3 hours before induction of anaesthesia may be of benefit in reduction of the incidence of gastro-oesophageal reflux during anaesthesia in dogs.

  6. WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, E; Racine, E; Beaulieu, L [CHU de Quebec - Universite Laval, Quebec, Quebec (Canada); Binnekamp, D [Integrated Clinical Solutions and Marketing, Philips Healthcare, Best, DA (Netherlands)

    2014-06-15

    Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.

  7. WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

    International Nuclear Information System (INIS)

    Poulin, E; Racine, E; Beaulieu, L; Binnekamp, D

    2014-01-01

    Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical

  8. High performance volume-of-intersection projectors for 3D-PET image reconstruction based on polar symmetries and SIMD vectorisation

    International Nuclear Information System (INIS)

    Scheins, J J; Vahedipour, K; Pietrzyk, U; Shah, N J

    2015-01-01

    For high-resolution, iterative 3D PET image reconstruction the efficient implementation of forward-backward projectors is essential to minimise the calculation time. Mathematically, the projectors are summarised as a system response matrix (SRM) whose elements define the contribution of image voxels to lines-of-response (LORs). In fact, the SRM easily comprises billions of non-zero matrix elements to evaluate the tremendous number of LORs as provided by state-of-the-art PET scanners. Hence, the performance of iterative algorithms, e.g. maximum-likelihood-expectation-maximisation (MLEM), suffers from severe computational problems due to the intensive memory access and huge number of floating point operations.Here, symmetries occupy a key role in terms of efficient implementation. They reduce the amount of independent SRM elements, thus allowing for a significant matrix compression according to the number of exploitable symmetries. With our previous work, the PET REconstruction Software TOolkit (PRESTO), very high compression factors (>300) are demonstrated by using specific non-Cartesian voxel patterns involving discrete polar symmetries. In this way, a pre-calculated memory-resident SRM using complex volume-of-intersection calculations can be achieved. However, our original ray-driven implementation suffers from addressing voxels, projection data and SRM elements in disfavoured memory access patterns. As a consequence, a rather limited numerical throughput is observed due to the massive waste of memory bandwidth and inefficient usage of cache respectively.In this work, an advantageous symmetry-driven evaluation of the forward-backward projectors is proposed to overcome these inefficiencies. The polar symmetries applied in PRESTO suggest a novel organisation of image data and LOR projection data in memory to enable an efficient single instruction multiple data vectorisation, i.e. simultaneous use of any SRM element for symmetric LORs. In addition, the calculation

  9. Refined 3d-3d correspondence

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F.; Genolini, Pietro Benetti; Bullimore, Mathew; Loon, Mark van [Mathematical Institute, University of Oxford, Andrew Wiles Building,Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG (United Kingdom)

    2017-04-28

    We explore aspects of the correspondence between Seifert 3-manifolds and 3d N=2 supersymmetric theories with a distinguished abelian flavour symmetry. We give a prescription for computing the squashed three-sphere partition functions of such 3d N=2 theories constructed from boundary conditions and interfaces in a 4d N=2{sup ∗} theory, mirroring the construction of Seifert manifold invariants via Dehn surgery. This is extended to include links in the Seifert manifold by the insertion of supersymmetric Wilson-’t Hooft loops in the 4d N=2{sup ∗} theory. In the presence of a mass parameter for the distinguished flavour symmetry, we recover aspects of refined Chern-Simons theory with complex gauge group, and in particular construct an analytic continuation of the S-matrix of refined Chern-Simons theory.

  10. Fast Gated EPR Imaging of the Beating Heart: Spatiotemporally-Resolved 3D Imaging of Free Radical Distribution during the Cardiac Cycle

    Science.gov (United States)

    Chen, Zhiyu; Reyes, Levy A.; Johnson, David H.; Velayutham, Murugesan; Yang, Changjun; Samouilov, Alexandre; Zweier, Jay L.

    2012-01-01

    In vivo or ex vivo electron paramagnetic resonance imaging (EPRI) is a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. However, applications of EPRI have been limited by long projection acquisition times and the consequent fact that rapid gated EPRI was not possible. Hence in vivo EPRI typically provided only time-averaged information. In order to achieve direct gated EPRI, a fast EPR acquisition scheme was developed to decrease EPR projection acquisition time down to 10 – 20 ms, along with corresponding software and instrumentation to achieve fast gated EPRI of the isolated beating heart with submillimeter spatial resolution in as little as 2 to 3 minutes. Reconstructed images display temporal and spatial variations of the free radical distribution, anatomical structure, and contractile function within the rat heart during the cardiac cycle. PMID:22473660

  11. A 3d-3d appetizer

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Du; Ye, Ke [Walter Burke Institute for Theoretical Physics, California Institute of Technology, Pasadena, CA, 91125 (United States)

    2016-11-02

    We test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N=2 “Lens space theory” T[L(p,1)] and the partition function of complex Chern-Simons theory on L(p,1). In particular, for p=1, we show how the familiar S{sup 3} partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[L(p,1)] becomes a constant independent of p. In addition, we study T[L(p,1)] on the squashed three-sphere S{sub b}{sup 3}. This enables us to see clearly, at the level of partition function, to what extent G{sub ℂ} complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.

  12. Parotid gland tumors: a comparison of postoperative radiotherapy techniques using three dimensional (3-D) dose distributions and dose-volume histograms (DVH)

    International Nuclear Information System (INIS)

    Yaparpalvi, R.; Tyerech, S.K.; Boselli, L.R.; Fontenla, D.P.; Beitler, J.J.; Vikram, B.

    1996-01-01

    Purpose/Objective: To compare different treatment techniques for unilateral treatment of parotid gland tumors. Materials and Methods: Twenty patients previously treated postoperatively for parotid gland tumors were retrospectively reviewed. Average field size was 9 x 11 cm, average separation was 15.5 cm, and the average prescription depth was 4.5 cm. Using 3-D dose distributions, tissue inhomogeneity corrections, scatter integration (for photons) and pencil beam (for electrons) algorithms and DVH, nine treatment techniques were compared using a representative patient. The treatment techniques investigated were: [1] unilateral 6 MV photons. [2] unilateral 12 MeV electrons. [3] unilateral 16 MeV electrons. [4] a ipsilateral wedge pair technique using 6 MV photons and a 45-degree wedge. [5] a 3-field AP (wedged), PA (wedged) and lateral portal technique using 6 MV photons. [6] a mixed beam technique using 6 MV photons and 12 MeV electrons (1:4 weighting). [7] a mixed beam technique using 6 MV photons and 16 MeV electrons (1:4 weighting). [8] a mixed beam technique using 18 MV photons and 20 MeV electrons (2:3 weighting). [9] a mixed beam technique using 18 MV photons and 20 MeV electrons (1:1 weighting). Results: Using dose-volume histograms to evaluate the dose to the contralateral parotid gland, the percentage of contralateral parotid volume receiving ≥30% of the prescribed dose was 100% for techniques [1], [8] and [9], and <5% for techniques [2] through [7]. Evaluating the 'hottest' 5 cc of the ipsilateral mandible and temporal lobes, the hot spots were: 152% and 150% for technique [2], 132% and 130% for technique [6]. Comparing the exit doses, techniques [1] and [8] contributed to ≥50% of the prescribed dose to the contralateral mandible and the temporal lobes. Only techniques [2] and [6] kept the highest point doses to both the brain stem and the spinal cord below 50% of the prescribed dose. Conclusion: The single photon lateral field [1] and the mixed

  13. 3-D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Holbek, Simon

    , if this significant reduction in the element count can still provide precise and robust 3-D vector flow estimates in a plane. The study concludes that the RC array is capable of estimating precise 3-D vector flow both in a plane and in a volume, despite the low channel count. However, some inherent new challenges...... ultrasonic vector flow estimation and bring it a step closer to a clinical application. A method for high frame rate 3-D vector flow estimation in a plane using the transverse oscillation method combined with a 1024 channel 2-D matrix array is presented. The proposed method is validated both through phantom...... hampers the task of real-time processing. In a second study, some of the issue with the 2-D matrix array are solved by introducing a 2-D row-column (RC) addressing array with only 62 + 62 elements. It is investigated both through simulations and via experimental setups in various flow conditions...

  14. ERP system for 3D printing industry

    Directory of Open Access Journals (Sweden)

    Deaky Bogdan

    2017-01-01

    Full Text Available GOCREATE is an original cloud-based production management and optimization service which helps 3D printing service providers to use their resources better. The proposed Enterprise Resource Planning system can significantly increase income through improved productivity. With GOCREATE, the 3D printing service providers get a much higher production efficiency at a much lower licensing cost, to increase their competitiveness in the fast growing 3D printing market.

  15. Innovation-Prototype. Making hydraulic and/or pneumatic plates using 3D printing technology

    Science.gov (United States)

    Alexa, V.; Rațiu, S. A.; Kiss, I.; Cioată, V. G.; Rackov, M.

    2018-01-01

    Start 3D printing allows hydraulic and/or pneumatic plates to be obtained from a single technological process without requiring further post-production operations. 3D printing with innovative materials in a rich colour range has several advantages such as: time-saving, cost is the same for any type of plate and its reported just to volume, fast and impossible realization of hydraulic and/or pneumatic links compared to traditional and high accuracy technologies.

  16. Robust extrapolation scheme for fast estimation of 3D Ising field partition functions: application to within subject fMRI data

    Energy Technology Data Exchange (ETDEWEB)

    Risser, L.; Vincent, T.; Ciuciu, Ph. [NeuroSpin CEA, F-91191 Gif sur Yvette (France); Risser, L.; Vincent, T. [Laboratoire de Neuroimagerie Assistee par Ordinateur (LNAO) CEA - DSV/I2BM/NEUROSPIN (France); Risser, L. [Institut de mecanique des fluides de Toulouse (IMFT), CNRS: UMR5502 - Universite Paul Sabatier - Toulouse III - Institut National Polytechnique de Toulouse - INPT (France); Idier, J. [Institut de Recherche en Communications et en Cybernetique de Nantes (IRCCyN) CNRS - UMR6597 - Universite de Nantes - ecole Centrale de Nantes - Ecole des Mines de Nantes - Ecole Polytechnique de l' Universite de Nantes (France)

    2009-07-01

    In this paper, we present a first numerical scheme to estimate Partition Functions (PF) of 3D Ising fields. Our strategy is applied to the context of the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated regions and estimate region-dependent, hemodynamic filters. For any region, a specific binary Markov random field may embody spatial correlation over the hidden states of the voxels by modeling whether they are activated or not. To make this spatial regularization fully adaptive, our approach is first based upon it, classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, file proposed extrapolation method allows its to approximate the PFs associated with the Ising fields defined over the remaining brain regions. In comparison with preexisting approaches, our method is robust; to topological inhomogeneities in the definition of the reference regions. As a result, it strongly alleviates the computational burden and makes spatially adaptive regularization of whole brain fMRI datasets feasible. (authors)

  17. 3D printing of functional structures

    NARCIS (Netherlands)

    Krijnen, Gijsbertus J.M.

    The technology colloquial known as ‘3D printing’ has developed in such diversity in printing technologies and application fields that meanwhile it seems anything is possible. However, clearly the ideal 3D Printer, with high resolution, multi-material capability, fast printing, etc. is yet to be

  18. 3D histomorphometric quantification from 3D computed tomography

    International Nuclear Information System (INIS)

    Oliveira, L.F. de; Lopes, R.T.

    2004-01-01

    The histomorphometric analysis is based on stereologic concepts and was originally applied to biologic samples. This technique has been used to evaluate different complex structures such as ceramic filters, net structures and cancellous objects that are objects with inner connected structures. The measured histomorphometric parameters of structure are: sample volume to total reconstructed volume (BV/TV), sample surface to sample volume (BS/BV), connection thickness (Tb Th ), connection number (Tb N ) and connection separation (Tb Sp ). The anisotropy was evaluated as well. These parameters constitute the base of histomorphometric analysis. The quantification is realized over cross-sections recovered by cone beam reconstruction, where a real-time microfocus radiographic system is used as tomographic system. The three-dimensional (3D) histomorphometry, obtained from tomography, corresponds to an evolution of conventional method that is based on 2D analysis. It is more coherent with morphologic and topologic context of the sample. This work shows result from 3D histomorphometric quantification to characterize objects examined by 3D computer tomography. The results, which characterizes the internal structures of ceramic foams with different porous density, are compared to results from conventional methods

  19. 3D virtuel udstilling

    DEFF Research Database (Denmark)

    Tournay, Bruno; Rüdiger, Bjarne

    2006-01-01

    3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....

  20. Underwater 3D filming

    Directory of Open Access Journals (Sweden)

    Roberto Rinaldi

    2014-12-01

    Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  1. Radiation-free 3D head shape and volume evaluation after endoscopically assisted strip craniectomy followed by helmet therapy for trigonocephaly

    NARCIS (Netherlands)

    de Jong, Guido; Tolhuisen, Manon; Meulstee, Jene; van der Heijden, Ferdinand; van Lindert, Erik; Borstlap, Wilfred; Maal, Thomas; Delye, Hans

    2017-01-01

    Introduction Radiation-free 3D post-operative sequential follow-up in craniosynostosis is hindered by the lack of consistent markers restricting evaluation to subjective comparison. However, using the computed cranial focal point (CCFP), it is possible to perform correct sequential image

  2. Radiation-free 3D head shape and volume evaluation after endoscopically assisted strip craniectomy followed by helmet therapy for trigonocephaly

    NARCIS (Netherlands)

    Jong, G.A. de; Tolhuisen, M.; Meulstee, J.W.; Heijden, F. van der; Lindert, E.J. van; Borstlap, W.A.; Maal, T.J.; Delye, H.H.

    2017-01-01

    INTRODUCTION: Radiation-free 3D post-operative sequential follow-up in craniosynostosis is hindered by the lack of consistent markers restricting evaluation to subjective comparison. However, using the computed cranial focal point (CCFP), it is possible to perform correct sequential image

  3. The impact of 3D volume of interest definition on accuracy and precision of activity estimation in quantitative SPECT and planar processing methods

    Science.gov (United States)

    He, Bin; Frey, Eric C.

    2010-06-01

    Accurate and precise estimation of organ activities is essential for treatment planning in targeted radionuclide therapy. We have previously evaluated the impact of processing methodology, statistical noise and variability in activity distribution and anatomy on the accuracy and precision of organ activity estimates obtained with quantitative SPECT (QSPECT) and planar (QPlanar) processing. Another important factor impacting the accuracy and precision of organ activity estimates is accuracy of and variability in the definition of organ regions of interest (ROI) or volumes of interest (VOI). The goal of this work was thus to systematically study the effects of VOI definition on the reliability of activity estimates. To this end, we performed Monte Carlo simulation studies using randomly perturbed and shifted VOIs to assess the impact on organ activity estimates. The 3D NCAT phantom was used with activities that modeled clinically observed 111In ibritumomab tiuxetan distributions. In order to study the errors resulting from misdefinitions due to manual segmentation errors, VOIs of the liver and left kidney were first manually defined. Each control point was then randomly perturbed to one of the nearest or next-nearest voxels in three ways: with no, inward or outward directional bias, resulting in random perturbation, erosion or dilation, respectively, of the VOIs. In order to study the errors resulting from the misregistration of VOIs, as would happen, e.g. in the case where the VOIs were defined using a misregistered anatomical image, the reconstructed SPECT images or projections were shifted by amounts ranging from -1 to 1 voxels in increments of with 0.1 voxels in both the transaxial and axial directions. The activity estimates from the shifted reconstructions or projections were compared to those from the originals, and average errors were computed for the QSPECT and QPlanar methods, respectively. For misregistration, errors in organ activity estimations were

  4. The impact of 3D volume of interest definition on accuracy and precision of activity estimation in quantitative SPECT and planar processing methods

    Energy Technology Data Exchange (ETDEWEB)

    He Bin [Division of Nuclear Medicine, Department of Radiology, New York Presbyterian Hospital-Weill Medical College of Cornell University, New York, NY 10021 (United States); Frey, Eric C, E-mail: bih2006@med.cornell.ed, E-mail: efrey1@jhmi.ed [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21287-0859 (United States)

    2010-06-21

    Accurate and precise estimation of organ activities is essential for treatment planning in targeted radionuclide therapy. We have previously evaluated the impact of processing methodology, statistical noise and variability in activity distribution and anatomy on the accuracy and precision of organ activity estimates obtained with quantitative SPECT (QSPECT) and planar (QPlanar) processing. Another important factor impacting the accuracy and precision of organ activity estimates is accuracy of and variability in the definition of organ regions of interest (ROI) or volumes of interest (VOI). The goal of this work was thus to systematically study the effects of VOI definition on the reliability of activity estimates. To this end, we performed Monte Carlo simulation studies using randomly perturbed and shifted VOIs to assess the impact on organ activity estimates. The 3D NCAT phantom was used with activities that modeled clinically observed {sup 111}In ibritumomab tiuxetan distributions. In order to study the errors resulting from misdefinitions due to manual segmentation errors, VOIs of the liver and left kidney were first manually defined. Each control point was then randomly perturbed to one of the nearest or next-nearest voxels in three ways: with no, inward or outward directional bias, resulting in random perturbation, erosion or dilation, respectively, of the VOIs. In order to study the errors resulting from the misregistration of VOIs, as would happen, e.g. in the case where the VOIs were defined using a misregistered anatomical image, the reconstructed SPECT images or projections were shifted by amounts ranging from -1 to 1 voxels in increments of with 0.1 voxels in both the transaxial and axial directions. The activity estimates from the shifted reconstructions or projections were compared to those from the originals, and average errors were computed for the QSPECT and QPlanar methods, respectively. For misregistration, errors in organ activity estimations

  5. Underwater 3D filming

    OpenAIRE

    Rinaldi, Roberto

    2014-01-01

    After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” ) and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Unde...

  6. Blender 3D cookbook

    CERN Document Server

    Valenza, Enrico

    2015-01-01

    This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'

  7. MRI of the anterior talofibular ligament, talar cartilage and os subfibulare: Comparison of isotropic resolution 3D and conventional 2D T2-weighted fast spin-echo sequences at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jisook; Cha, Jang Gyu [Soonchunhyang University Bucheon Hospital, Department of Radiology, Wonmi-gu, Bucheon-si (Korea, Republic of); Lee, Young Koo [Soonchunhyang University Bucheon Hospital, Department of Orthopedics, Wonmi-gu, Bucheon-si (Korea, Republic of); Lee, Bo Ra [Soonchunhyang University Bucheon Hospital, Department of Biomedical Statistics, Wonmi-gu, Bucheon-si (Korea, Republic of); Jeon, Chan Hong [Soonchunhyang University Bucheon Hospital, Division of Rheumatology, Department of Internal Medicine, Wonmi-gu, Bucheon-si (Korea, Republic of)

    2016-07-15

    To determine the accuracy of a three-dimensional (3D) T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequence compared with two-dimensional (2D) sequence for diagnosing anterior talofibular ligament (ATFL) tears, chondral lesion of the talus (CLT) and os subfibulare/avulsion fracture of the distal fibula (OSF). Thirty-five patients were included, who had undergone ankle MRI with 3D T2-weighted FSE and 2D T2-weighted FSE sequences, as well as subsequent ankle arthroscopy, between November 2013 and July 2014. Each MR imaging sequence was independently scored by two readers retrospectively for the presence of ATFL tears, CLT and OSF. The area under the receiver operating curve (AUC) was compared to determine the discriminatory power of the two image sequences. Interobserver agreement was expressed as unweighted kappa value. Arthroscopic findings confirmed 21 complete tears of the ATFL, 14 partial tears of the ATFL, 17 CLTs and 7 OSFs. There were no significant differences in the diagnoses of ATFL tears (p = 0.074-0.501), CLT (p = 0.090-0.450) and OSF (p = 0.317) obtained from the 2D and 3D sequences by either reader. The interobserver agreement rates between two readers using the 3D T2-weighted FSE sequence versus those obtained with the 2D sequence were substantial (κ = 0.659) versus moderate (κ = 0.553) for ATFL tears, moderate (κ = 0.499) versus substantial (κ = 0.676) for CLT and substantial (κ = 0.621) versus substantial (κ = 0.689) for OSF. Three-dimensional isotropic T2-weighted FSE MRI of the ankle resulted in no statistically significant difference in diagnostic performance compared to two-dimensional T2-weighted FSE MRI in the evaluation of ATFL tears, CLTs and OSFs. (orig.)

  8. MRI of the anterior talofibular ligament, talar cartilage and os subfibulare: Comparison of isotropic resolution 3D and conventional 2D T2-weighted fast spin-echo sequences at 3.0 T

    International Nuclear Information System (INIS)

    Yi, Jisook; Cha, Jang Gyu; Lee, Young Koo; Lee, Bo Ra; Jeon, Chan Hong

    2016-01-01

    To determine the accuracy of a three-dimensional (3D) T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequence compared with two-dimensional (2D) sequence for diagnosing anterior talofibular ligament (ATFL) tears, chondral lesion of the talus (CLT) and os subfibulare/avulsion fracture of the distal fibula (OSF). Thirty-five patients were included, who had undergone ankle MRI with 3D T2-weighted FSE and 2D T2-weighted FSE sequences, as well as subsequent ankle arthroscopy, between November 2013 and July 2014. Each MR imaging sequence was independently scored by two readers retrospectively for the presence of ATFL tears, CLT and OSF. The area under the receiver operating curve (AUC) was compared to determine the discriminatory power of the two image sequences. Interobserver agreement was expressed as unweighted kappa value. Arthroscopic findings confirmed 21 complete tears of the ATFL, 14 partial tears of the ATFL, 17 CLTs and 7 OSFs. There were no significant differences in the diagnoses of ATFL tears (p = 0.074-0.501), CLT (p = 0.090-0.450) and OSF (p = 0.317) obtained from the 2D and 3D sequences by either reader. The interobserver agreement rates between two readers using the 3D T2-weighted FSE sequence versus those obtained with the 2D sequence were substantial (κ = 0.659) versus moderate (κ = 0.553) for ATFL tears, moderate (κ = 0.499) versus substantial (κ = 0.676) for CLT and substantial (κ = 0.621) versus substantial (κ = 0.689) for OSF. Three-dimensional isotropic T2-weighted FSE MRI of the ankle resulted in no statistically significant difference in diagnostic performance compared to two-dimensional T2-weighted FSE MRI in the evaluation of ATFL tears, CLTs and OSFs. (orig.)

  9. 3-DB, 3-D Multigroup Diffusion, X-Y-Z, R-Theta-Z, Triangular-Z Geometry, Fast Reactor Burnup

    International Nuclear Information System (INIS)

    Hardie, R.W.; Little, W.W. Jr.; Mroz, W.

    1974-01-01

    1 - Description of problem or function: 3DB is a three-dimensional (x-y-z, r-theta-z, triangular-z) multigroup diffusion code for use in detailed fast-reactor criticality and burnup analysis. The code can be used to - (a) compute k eff and perform criticality searches on time absorption, reactor composition, and reactor dimensions by means of either a flux or an adjoint model, (b) compute material burnup using a flexible material shuffling scheme, and (c) compute flux distributions for an arbitrary extraneous source. 2 - Method of solution: Eigenvalues are computed by standard source- iteration techniques. Group re-balancing and successive over-relaxation with line inversion are used to accelerate convergence. Adjoint solutions are obtained by inverting the input data and redefining the source terms. Material burnup is by reactor zone. The burnup rate is determined by the zone and energy-averaged cross sections which are recomputed after each time-step. The isotopic chains, which can contain any number of isotopes are formed by the user. The code does not contain built- in or internal chains. 3 - Restrictions on the complexity of the problem: Since variable dimensioning is employed, no simple bounds can be stated

  10. Summary Report on Phase I and Phase II Results From the 3D Printing in Zero-G Technology Demonstration Mission. Volume II

    Science.gov (United States)

    Prater, T. J.; Werkheiser, N. J.; Ledbetter, F. E., III

    2018-01-01

    In-space manufacturing seeks to develop the processes, skill sets, and certification architecture needed to provide a rapid response manufacturing capability on long-duration exploration missions. The first 3D printer on the Space Station was developed by Made in Space, Inc. and completed two rounds of operation on orbit as part of the 3D Printing in Zero-G Technology Demonstration Mission. This Technical Publication provides a comprehensive overview of the technical objections of the mission, the two phases of hardware operation conducted on orbit, and the subsequent detailed analysis of specimens produced. No engineering significant evidence of microgravity effects on material outcomes was noted. This technology demonstration mission represents the first step in developing a suite of manufacturing capabilities to meet future mission needs.

  11. From 3D view to 3D print

    Science.gov (United States)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  12. DELTA 3D PRINTER

    Directory of Open Access Journals (Sweden)

    ȘOVĂILĂ Florin

    2016-07-01

    Full Text Available 3D printing is a very used process in industry, the generic name being “rapid prototyping”. The essential advantage of a 3D printer is that it allows the designers to produce a prototype in a very short time, which is tested and quickly remodeled, considerably reducing the required time to get from the prototype phase to the final product. At the same time, through this technique we can achieve components with very precise forms, complex pieces that, through classical methods, could have been accomplished only in a large amount of time. In this paper, there are presented the stages of a 3D model execution, also the physical achievement after of a Delta 3D printer after the model.

  13. Forensic 3D Scene Reconstruction

    International Nuclear Information System (INIS)

    LITTLE, CHARLES Q.; PETERS, RALPH R.; RIGDON, J. BRIAN; SMALL, DANIEL E.

    1999-01-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene

  14. Professional Papervision3D

    CERN Document Server

    Lively, Michael

    2010-01-01

    Professional Papervision3D describes how Papervision3D works and how real world applications are built, with a clear look at essential topics such as building websites and games, creating virtual tours, and Adobe's Flash 10. Readers learn important techniques through hands-on applications, and build on those skills as the book progresses. The companion website contains all code examples, video step-by-step explanations, and a collada repository.

  15. Feasible voltage-tap based quench detection in a Ag/Bi-2212 coil enabled by fast 3D normal zone propagation

    International Nuclear Information System (INIS)

    Shen, Tengming; Ye, Liyang; Li, Pei

    2016-01-01

    For this study, small insert solenoids have been built using a commercial Ag/Bi-2212 multifilamentary round wire, insulated with a new thin TiO 2 – polymer coating insulation (thickness in ~20 μm versus ~100 μm for a commonly used mullite braided sleeve insulation), and characterized in background magnetic field up to 14 T at 4.2 K to explore the high-field performance and quench detection of Bi-2212 magnets. The coil has no visible leakage and no electrical shorts after reaction, and it carries 280 A/mm -2 in a background field 14 T and generates an additional 1.7 T. A notable result is that, despite normal zones propagate slowly along the conductor, the hot spot temperature upon detection increases only from 40 K to 60 K when the resistive quench detection voltage threshold increases from 0.1 V to 1 V for all operating current density investigated, showing that quench detection using voltage taps is feasible for this coil. This is in a strong contrast to a coil we previously built to the same specifications but from wires insulated with the mullite braided sleeve insulation, for which the hot spot temperature upon detection increases from ~80 K to ~140 K while increasing from the detection voltage threshold from 0.1 V to 1 V, and thus for which quench detection using voltage taps presents significant risks, consistent with the common belief that the effectiveness of quench detection using voltage taps for superconducting magnets built using high temperature superconductors is seriously compromised by their slow normal zone propagation. This striking difference is ascribed to the fast transverse quench propagation enabled by thin insulation and improved thermal coupling between conductor turns. Finally, this work demonstrates that quench detection for high-temperature superconducting magnets highly depends on the design and construction of the coils such as insulation materials used and this dependence should be factored into the overall magnet design

  16. A fundamental study of non-contrast enhanced MR angiography using ECG gated-3D fast spin echo at 3.0 T

    International Nuclear Information System (INIS)

    Nakato, Kengo; Hiai, Yasuhiro; Tomiguchi, Seiji

    2010-01-01

    Contrast-enhanced magnetic resonance angiography (CE-MRA) is frequently performed in body and extremity studies because of its superior ability to detect the vascular stenosis. However, nephrotoxicity of the contrast medium has been emphasized in recent years. Non-contrast MRA using the three-dimensional electrocardiogram-synchronized fast spin echo method (fresh blood imaging (FBI), non-contrast MRA of arteries and veins (NATIVE) and triggered acquisition non contrast enhancement MRA (TRANCE)) is recommended as a substitute for CE-MRA. There are a few reports in the literature that evaluate the detectability of vascular stenosis using non-contrast MRA on 3.0 T MRI. The purpose of this study was to evaluate the detectability of vascular stenosis using non-contrast MRA at 3.0 T with an original vascular phantom. The vascular phantom consisted of silicon tubes. 30% and 70% stenosis of luminal diameter were made. Each silicon tube connected a pump producing a pulsatile flow. A flowing material to was used in this study to show the similarity of the intensity to blood on MRI. MRA without a contrast medium (NATIVE sequence) were performed in the vascular phantom by changing the image matrix, static magnetic field strength and flow velocity. In addition, the NATIVE sequence was used with or without flow compensation. Vascular stenosis was quantitatively estimated by measurement of the signal intensities in non-contrast MRA images. MRA with NATIVE sequence demonstrated an accurate estimation of 30% vascular stenosis at slow flow velocity. However, 30% stenosis was overestimated in cases of high flow velocity. Estimation was improved by using a flow compensation sequence. 70% stenosis was overestimated on MRA with NATIVE sequence. Estimation of 70% stenosis was improved by using a flow compensation sequence. Accurate estimation of vascular stenosis in MRA with a NATIVE sequence is improved by using the flow compensation technique. MRA with NATIVE sequence is considered to

  17. Changes in the volume and circumference of the torso, leg and arm after cycling in the heat determined using 3D whole body scanners : conference paper, Lugano, Switzerland,

    NARCIS (Netherlands)

    Hein, Daanen; Vonk, L.A.

    2016-01-01

    Whole body volume changes due to sweat loss after exercise in the heat are well documented, but little is known about the relative contribution of the torso and extremities to these volume changes. It is the purpose of this study to quantify these effects. Therefore, seven healthy male subjects were

  18. A method to combine target volume data from 3D and 4D planned thoracic radiotherapy patient cohorts for machine learning applications

    NARCIS (Netherlands)

    Johnson, Corinne; Price, Gareth; Khalifa, Jonathan; Faivre-Finn, Corinne; Dekker, Andre; Moore, Christopher; van Herk, Marcel

    2017-01-01

    The gross tumour volume (GTV) is predictive of clinical outcome and consequently features in many machine-learned models. 4D-planning, however, has prompted substitution of the GTV with the internal gross target volume (iGTV). We present and validate a method to synthesise GTV data from the iGTV,

  19. [Real time 3D echocardiography

    Science.gov (United States)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  20. Fast MR Imaging of the Paediatric Abdomen with CAIPIRINHA-Accelerated T1w 3D FLASH and with High-Resolution T2w HASTE: A Study on Image Quality

    Directory of Open Access Journals (Sweden)

    Mengxia Li

    2015-01-01

    Full Text Available The aim of this study was to explore the applicability of fast MR techniques to routine paediatric abdominopelvic MRI at 1.5 Tesla. “Controlled Aliasing in Parallel Imaging Results in Higher Acceleration-” (CAIPIRINHA- accelerated contrast-enhanced-T1w 3D FLASH imaging was compared to standard T1w 2D FLASH imaging with breath-holding in 40 paediatric patients and to respiratory-triggered T1w TSE imaging in 10 sedated young children. In 20 nonsedated patients, we compared T2w TIRM to fat-saturated T2w HASTE imaging. Two observers performed an independent and blinded assessment of overall image quality. Acquisition time was reduced by the factor of 15 with CAIPIRINHA-accelerated T1w FLASH and by 7 with T2w HASTE. With CAIPIRINHA and with HASTE, there were significantly less motion artefacts in nonsedated patients. In sedated patients, respiratory-triggered T1w imaging in general showed better image quality. However, satisfactory image quality was achieved with CAIPIRINHA in two sedated patients where respiratory triggering failed. In summary, fast scanning with CAIPIRINHA and HASTE presents a reliable high quality alternative to standard sequences in paediatric abdominal MRI. Paediatric patients, in particular, benefit greatly from fast image acquisition with less breath-hold cycles or shorter sedation.

  1. 3D composite image, 3D MRI, 3D SPECT, hydrocephalus

    International Nuclear Information System (INIS)

    Mito, T.; Shibata, I.; Sugo, N.; Takano, M.; Takahashi, H.

    2002-01-01

    The three-dimensional (3D)SPECT imaging technique we have studied and published for the past several years is an analytical tool that permits visual expression of the cerebral circulation profile in various cerebral diseases. The greatest drawback of SPECT is that the limitation on precision of spacial resolution makes intracranial localization impossible. In 3D SPECT imaging, intracranial volume and morphology may vary with the threshold established. To solve this problem, we have produced complimentarily combined SPECT and helical-CT 3D images by means of general-purpose visualization software for intracranial localization. In hydrocephalus, however, the key subject to be studied is the profile of cerebral circulation around the ventricles of the brain. This suggests that, for displaying the cerebral ventricles in three dimensions, CT is a difficult technique whereas MRI is more useful. For this reason, we attempted to establish the profile of cerebral circulation around the cerebral ventricles by the production of combined 3D images of SPECT and MRI. In patients who had shunt surgery for hydrocephalus, a difference between pre- and postoperative cerebral circulation profiles was assessed by a voxel distribution curve, 3D SPECT images, and combined 3D SPECT and MRI images. As the shunt system in this study, an Orbis-Sigma valve of the automatic cerebrospinal fluid volume adjustment type was used in place of the variable pressure type Medos valve currently in use, because this device requires frequent changes in pressure and a change in pressure may be detected after MRI procedure. The SPECT apparatus used was PRISM3000 of the three-detector type, and 123I-IMP was used as the radionuclide in a dose of 222 MBq. MRI data were collected with an MAGNEXa+2 with a magnetic flux density of 0.5 tesla under the following conditions: field echo; TR 50 msec; TE, 10 msec; flip, 30ueK; 1 NEX; FOV, 23 cm; 1-mm slices; and gapless. 3D images are produced on the workstation TITAN

  2. Comparison of two-dimensional fast spin echo T2 weighted sequences and three-dimensional volume isotropic T2 weighted fast spin echo (VISTA) MRI in the evaluation of triangular fibrocartilage of the wrist.

    Science.gov (United States)

    Park, Hee Jin; Lee, So Yeon; Kang, Kyung A; Kim, Eun Young; Shin, Hun Kyu; Park, Se Jin; Park, Jai Hyung; Kim, Eugene

    2018-04-01

    To compare image quality of three-dimensional volume isotropic T 2 weighted fast spin echo (3D VISTA) and two-dimensional (2D) T 2 weighted images (T2WI) for evaluation of triangular fibrocartilage (TFC) and to investigate whether 3D VISTA can replace 2D T 2 WI in evaluating TFC injury. This retrospective study included 69 patients who received wrist MRIs using both 2D T 2 WI and 3D VISTA techniques for assessment of wrist pathology, including TFC injury. Two radiologists measured the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of the two sequences. The anatomical identification score and diagnostic performance were independently assessed by two interpreters. The diagnostic abilities of 3D VISTA and 2D T 2 WI were analysed by sensitivity, specificity and accuracy for diagnosing TFC injury using surgically or clinically confirmed diagnostic reference standards. 17 cases (25%) were classified as having TFC injury. 2 cases (12%) were diagnosed surgically, and 15 cases (88%) were diagnosed by physical examination. 52 cases (75%) were diagnosed as having intact TFC. 8 of these cases (15%) were surgically confirmed, while the others were diagnosed by physical examination and clinical findings. The 3D VISTA images had significantly higher SNR and CNR values for the TFC than 2D T 2 WI images. The scores of 3D VISTA's total length, full width and sharpness were similar to those of 2D T 2 WI. We were unable to find a significant difference between 3D VISTA and 2D T 2 WI in the ability to diagnose TFC injury. 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment. Advances in knowledge: 3D VISTA image quality is similar to that of 2D T 2 WI for TFC evaluation and is also excellent for tissue contrast. 3D VISTA can replace 2D images in TFC injury assessment.

  3. Mister Voxel: 3D internal dosimetry software for nuclear medicine

    International Nuclear Information System (INIS)

    McKay, E.

    1998-01-01

    Full text: Calculation of individual internal dosimetry in nuclear medicine is a complex, multi-stage process. Most often, calculations are biased on the MIRD methodology, which assumes uniform distribution of cumulated activity inside a set of mathematically described internal organs. The MIRD 'reference man' geometry is highly simplified and the dosimetry estimates generated by this method were originally only intended to predict the average dose expected in an exposed population. We have developed a software package for the Macintosh computer ('Mister Voxel') that uses a fast Fourier transform to calculate the 3D distribution of absorbed dose by convolving a 3D dose kernel with a 3D distribution of cumulated activity. This makes it possible to generate dose volume histograms and isodose contours for organs or tumours treated with radiopharmaceuticals, a task not possible using the MIRD technique. In addition to providing 3D convolution, Mister Voxel performs basic image processing functions (image math, filters, cut and paste) and provides a collection of painting tools and simple morphological operators to facilitate the delineation of regions of interest (ROIs) along anatomical boundaries. The package also includes an image registration module with tools for automated or manual registration of 3D data sets. The structure of the package allows ROIs drawn on CT or MRI data to be easily transferred to registered SPECT data. Dose kernels are implemented by plug-in code modules, allowing the user to extend the system's capabilities if required. File import and export capabilities are also extensible

  4. Wearable 3D measurement

    Science.gov (United States)

    Manabe, Yoshitsugu; Imura, Masataka; Tsuchiya, Masanobu; Yasumuro, Yoshihiro; Chihara, Kunihiro

    2003-01-01

    Wearable 3D measurement realizes to acquire 3D information of an objects or an environment using a wearable computer. Recently, we can send voice and sound as well as pictures by mobile phone in Japan. Moreover it will become easy to capture and send data of short movie by it. On the other hand, the computers become compact and high performance. And it can easy connect to Internet by wireless LAN. Near future, we can use the wearable computer always and everywhere. So we will be able to send the three-dimensional data that is measured by wearable computer as a next new data. This paper proposes the measurement method and system of three-dimensional data of an object with the using of wearable computer. This method uses slit light projection for 3D measurement and user"s motion instead of scanning system.

  5. 3D Digital Modelling

    DEFF Research Database (Denmark)

    Hundebøl, Jesper

    wave of new building information modelling tools demands further investigation, not least because of industry representatives' somewhat coarse parlance: Now the word is spreading -3D digital modelling is nothing less than a revolution, a shift of paradigm, a new alphabet... Research qeustions. Based...... on empirical probes (interviews, observations, written inscriptions) within the Danish construction industry this paper explores the organizational and managerial dynamics of 3D Digital Modelling. The paper intends to - Illustrate how the network of (non-)human actors engaged in the promotion (and arrest) of 3...... important to appreciate the analysis. Before turning to the presentation of preliminary findings and a discussion of 3D digital modelling, it begins, however, with an outline of industry specific ICT strategic issues. Paper type. Multi-site field study...

  6. 6567 Volume 12 No. 5 August 2012 DETERMINANTS OF FAST ...

    African Journals Online (AJOL)

    HENRY

    2012-08-05

    Aug 5, 2012 ... urbanization in Uganda offers new market opportunities for ... requires knowledge of the behaviour of consumers who eat away from home. ... This study on the determinants of fast-food consumption in Kampala district is the ..... which in this case is age, marital status, occupation and time spent away from ...

  7. 3D ARCHITECTURAL VIDEOMAPPING

    Directory of Open Access Journals (Sweden)

    R. Catanese

    2013-07-01

    Full Text Available 3D architectural mapping is a video projection technique that can be done with a survey of a chosen building in order to realize a perfect correspondence between its shapes and the images in projection. As a performative kind of audiovisual artifact, the real event of the 3D mapping is a combination of a registered video animation file with a real architecture. This new kind of visual art is becoming very popular and its big audience success testifies new expressive chances in the field of urban design. My case study has been experienced in Pisa for the Luminara feast in 2012.

  8. Interaktiv 3D design

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2002-01-01

    Projektet undersøger potentialet for interaktiv 3D design via Internettet. Arkitekt Jørn Utzons projekt til Espansiva blev udviklet som et byggesystem med det mål, at kunne skabe mangfoldige planmuligheder og mangfoldige facade- og rumudformninger. Systemets bygningskomponenter er digitaliseret som...... 3D elementer og gjort tilgængelige. Via Internettet er det nu muligt at sammenstille og afprøve en uendelig  række bygningstyper som  systemet blev tænkt og udviklet til....

  9. 3D Projection Installations

    DEFF Research Database (Denmark)

    Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle

    2014-01-01

    Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article ...... Fingerplan to Loop City, is a 3-D projection installation presenting the history and future of city planning for the Copenhagen area in Denmark. The installation was presented as part of the 12th Architecture Biennale in Venice in 2010....

  10. Herramientas SIG 3D

    Directory of Open Access Journals (Sweden)

    Francisco R. Feito Higueruela

    2010-04-01

    Full Text Available Applications of Geographical Information Systems on several Archeology fields have been increasing during the last years. Recent avances in these technologies make possible to work with more realistic 3D models. In this paper we introduce a new paradigm for this system, the GIS Thetrahedron, in which we define the fundamental elements of GIS, in order to provide a better understanding of their capabilities. At the same time the basic 3D characteristics of some comercial and open source software are described, as well as the application to some samples on archeological researchs

  11. Bootstrapping 3D fermions

    Energy Technology Data Exchange (ETDEWEB)

    Iliesiu, Luca [Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States); Kos, Filip; Poland, David [Department of Physics, Yale University, New Haven, CT 06520 (United States); Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States); Simmons-Duffin, David [School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540 (United States); Yacoby, Ran [Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (United States)

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions 〈ψψψψ〉 in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ×ψ OPE, and also on the central charge C{sub T}. We observe features in our bounds that coincide with scaling dimensions in the Gross-Neveu models at large N. We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  12. New simple method for fast and accurate measurement of volumes

    International Nuclear Information System (INIS)

    Frattolillo, Antonio

    2006-01-01

    A new simple method is presented, which allows us to measure in just a few minutes but with reasonable accuracy (less than 1%) the volume confined inside a generic enclosure, regardless of the complexity of its shape. The technique proposed also allows us to measure the volume of any portion of a complex manifold, including, for instance, pipes and pipe fittings, valves, gauge heads, and so on, without disassembling the manifold at all. To this purpose an airtight variable volume is used, whose volume adjustment can be precisely measured; it has an overall capacity larger than that of the unknown volume. Such a variable volume is initially filled with a suitable test gas (for instance, air) at a known pressure, as carefully measured by means of a high precision capacitive gauge. By opening a valve, the test gas is allowed to expand into the previously evacuated unknown volume. A feedback control loop reacts to the resulting finite pressure drop, thus contracting the variable volume until the pressure exactly retrieves its initial value. The overall reduction of the variable volume achieved at the end of this process gives a direct measurement of the unknown volume, and definitively gets rid of the problem of dead spaces. The method proposed actually does not require the test gas to be rigorously held at a constant temperature, thus resulting in a huge simplification as compared to complex arrangements commonly used in metrology (gas expansion method), which can grant extremely accurate measurement but requires rather expensive equipments and results in time consuming methods, being therefore impractical in most applications. A simple theoretical analysis of the thermodynamic cycle and the results of experimental tests are described, which demonstrate that, in spite of its simplicity, the method provides a measurement accuracy within 0.5%. The system requires just a few minutes to complete a single measurement, and is ready immediately at the end of the process. The

  13. Min-max Extrapolation Scheme for Fast Estimation of 3D Potts Field Partition Functions. Application to the Joint Detection-Estimation of Brain Activity in fMRI

    International Nuclear Information System (INIS)

    Risser, L.; Vincent, T.; Ciuciu, P.; Risser, L.; Idier, J.; Risser, L.; Forbes, F.

    2011-01-01

    In this paper, we propose a fast numerical scheme to estimate Partition Functions (PF) of symmetric Potts fields. Our strategy is first validated on 2D two-color Potts fields and then on 3D two- and three-color Potts fields. It is then applied to the joint detection-estimation of brain activity from functional Magnetic Resonance Imaging (fMRI) data, where the goal is to automatically recover activated, deactivated and inactivated brain regions and to estimate region dependent hemodynamic filters. For any brain region, a specific 3D Potts field indeed embodies the spatial correlation over the hidden states of the voxels by modeling whether they are activated, deactivated or inactive. To make spatial regularization adaptive, the PFs of the Potts fields over all brain regions are computed prior to the brain activity estimation. Our approach is first based upon a classical path-sampling method to approximate a small subset of reference PFs corresponding to pre-specified regions. Then, we propose an extrapolation method that allows us to approximate the PFs associated to the Potts fields defined over the remaining brain regions. In comparison with preexisting methods either based on a path sampling strategy or mean-field approximations, our contribution strongly alleviates the computational cost and makes spatially adaptive regularization of whole brain fMRI datasets feasible. It is also robust against grid inhomogeneities and efficient irrespective of the topological configurations of the brain regions. (authors)

  14. Compact 3D quantum memory

    Science.gov (United States)

    Xie, Edwar; Deppe, Frank; Renger, Michael; Repp, Daniel; Eder, Peter; Fischer, Michael; Goetz, Jan; Pogorzalek, Stefan; Fedorov, Kirill G.; Marx, Achim; Gross, Rudolf

    2018-05-01

    Superconducting 3D microwave cavities offer state-of-the-art coherence times and a well-controlled environment for superconducting qubits. In order to realize at the same time fast readout and long-lived quantum information storage, one can couple the qubit to both a low-quality readout and a high-quality storage cavity. However, such systems are bulky compared to their less coherent 2D counterparts. A more compact and scalable approach is achieved by making use of the multimode structure of a 3D cavity. In our work, we investigate such a device where a transmon qubit is capacitively coupled to two modes of a single 3D cavity. External coupling is engineered so that the memory mode has an about 100 times larger quality factor than the readout mode. Using an all-microwave second-order protocol, we realize a lifetime enhancement of the stored state over the qubit lifetime by a factor of 6 with a fidelity of approximately 80% determined via quantum process tomography. We also find that this enhancement is not limited by fundamental constraints.

  15. Accurate and reproducible reconstruction of coronary arteries and endothelial shear stress calculation using 3D OCT: comparative study to 3D IVUS and 3D QCA.

    Science.gov (United States)

    Toutouzas, Konstantinos; Chatzizisis, Yiannis S; Riga, Maria; Giannopoulos, Andreas; Antoniadis, Antonios P; Tu, Shengxian; Fujino, Yusuke; Mitsouras, Dimitrios; Doulaverakis, Charalampos; Tsampoulatidis, Ioannis; Koutkias, Vassilis G; Bouki, Konstantina; Li, Yingguang; Chouvarda, Ioanna; Cheimariotis, Grigorios; Maglaveras, Nicos; Kompatsiaris, Ioannis; Nakamura, Sunao; Reiber, Johan H C; Rybicki, Frank; Karvounis, Haralambos; Stefanadis, Christodoulos; Tousoulis, Dimitris; Giannoglou, George D

    2015-06-01

    Geometrically-correct 3D OCT is a new imaging modality with the potential to investigate the association of local hemodynamic microenvironment with OCT-derived high-risk features. We aimed to describe the methodology of 3D OCT and investigate the accuracy, inter- and intra-observer agreement of 3D OCT in reconstructing coronary arteries and calculating ESS, using 3D IVUS and 3D QCA as references. 35 coronary artery segments derived from 30 patients were reconstructed in 3D space using 3D OCT. 3D OCT was validated against 3D IVUS and 3D QCA. The agreement in artery reconstruction among 3D OCT, 3D IVUS and 3D QCA was assessed in 3-mm-long subsegments using lumen morphometry and ESS parameters. The inter- and intra-observer agreement of 3D OCT, 3D IVUS and 3D QCA were assessed in a representative sample of 61 subsegments (n = 5 arteries). The data processing times for each reconstruction methodology were also calculated. There was a very high agreement between 3D OCT vs. 3D IVUS and 3D OCT vs. 3D QCA in terms of total reconstructed artery length and volume, as well as in terms of segmental morphometric and ESS metrics with mean differences close to zero and narrow limits of agreement (Bland-Altman analysis). 3D OCT exhibited excellent inter- and intra-observer agreement. The analysis time with 3D OCT was significantly lower compared to 3D IVUS. Geometrically-correct 3D OCT is a feasible, accurate and reproducible 3D reconstruction technique that can perform reliable ESS calculations in coronary arteries. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. Depiction of the cranial nerves around the cavernous sinus by 3D reversed FISP with diffusion weighted imaging (3D PSIF-DWI)

    International Nuclear Information System (INIS)

    Ishida, Go; Oishi, Makoto; Jinguji, Shinya; Yoneoka, Yuichiro; Fujii, Yukihiko; Sato, Mitsuya

    2011-01-01

    The purpose of this study was to evaluate the anatomy of cranial nerves running in and around the cavernous sinus, we employed three-dimensional reversed fast imaging with steady-state precession (FISP) with diffusion weighted imaging (3D PSIF-DWI) on 3-T magnetic resonance (MR) system. After determining the proper parameters to obtain sufficient resolution of 3D PSIF-DWI, we collected imaging data of 20-side cavernous regions in 10 normal subjects. 3D PSIF-DWI provided high contrast between the cranial nerves and other soft tissues, fluid, and blood in all subjects. We also created volume-rendered images of 3D PSIF-DWI and anatomically evaluated the reliability of visualizing optic, oculomotor, trochlear, trigeminal, and abducens nerves on 3D PSIF-DWI. All 20 sets of cranial nerves were visualized and 12 trochlear nerves and 6 abducens nerves were partially identified. We also presented preliminary clinical experiences in two cases with pituitary adenomas. The anatomical relationship between the tumor and cranial nerves running in and around the cavernous sinus could be three-dimensionally comprehended by 3D PSIF-DWI and the volume-rendered images. In conclusion, 3D PSIF-DWI has great potential to provide high resolution 'cranial nerve imaging', which visualizes the whole length of the cranial nerves including the parts in the blood flow as in the cavernous sinus region. (author)

  17. [Depiction of the cranial nerves around the cavernous sinus by 3D reversed FISP with diffusion weighted imaging (3D PSIF-DWI)].

    Science.gov (United States)

    Ishida, Go; Oishi, Makoto; Jinguji, Shinya; Yoneoka, Yuichiro; Sato, Mitsuya; Fujii, Yukihiko

    2011-10-01

    To evaluate the anatomy of cranial nerves running in and around the cavernous sinus, we employed three-dimensional reversed fast imaging with steady-state precession (FISP) with diffusion weighted imaging (3D PSIF-DWI) on 3-T magnetic resonance (MR) system. After determining the proper parameters to obtain sufficient resolution of 3D PSIF-DWI, we collected imaging data of 20-side cavernous regions in 10 normal subjects. 3D PSIF-DWI provided high contrast between the cranial nerves and other soft tissues, fluid, and blood in all subjects. We also created volume-rendered images of 3D PSIF-DWI and anatomically evaluated the reliability of visualizing optic, oculomotor, trochlear, trigeminal, and abducens nerves on 3D PSIF-DWI. All 20 sets of cranial nerves were visualized and 12 trochlear nerves and 6 abducens nerves were partially identified. We also presented preliminary clinical experiences in two cases with pituitary adenomas. The anatomical relationship between the tumor and cranial nerves running in and around the cavernous sinus could be three-dimensionally comprehended by 3D PSIF-DWI and the volume-rendered images. In conclusion, 3D PSIF-DWI has great potential to provide high resolution "cranial nerve imaging", which visualizes the whole length of the cranial nerves including the parts in the blood flow as in the cavernous sinus region.

  18. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data...

  19. 3D Wire 2015

    DEFF Research Database (Denmark)

    Jordi, Moréton; F, Escribano; J. L., Farias

    This document is a general report on the implementation of gamification in 3D Wire 2015 event. As the second gamification experience in this event, we have delved deeply in the previous objectives (attracting public areas less frequented exhibition in previous years and enhance networking) and have...

  20. 3D Harmonic Echocardiography:

    NARCIS (Netherlands)

    M.M. Voormolen (Marco)

    2007-01-01

    textabstractThree dimensional (3D) echocardiography has recently developed from an experimental technique in the ’90 towards an imaging modality for the daily clinical practice. This dissertation describes the considerations, implementation, validation and clinical application of a unique

  1. Magmatic Systems in 3-D

    Science.gov (United States)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  2. Characterization of Distinct Astrocytic Populations Responding with Different Volume Changes to Oxygen-Glucose Deprivation: 3d Confocal Morphometry And Single-Cell Gene Expression Profilig

    Czech Academy of Sciences Publication Activity Database

    Benešová, Jana; Rusňáková, Vendula; Honsa, Pavel; Pivoňková, Helena; Kubista, Mikael; Anděrová, Miroslava

    2011-01-01

    Roč. 59, Supplement 1 (2011), S126-S126 ISSN 0894-1491. [European meeting on Glia l Cells in Health and Disease /10./. 13.09.2011-13.09.2011, Prague] Institutional research plan: CEZ:AV0Z50390703; CEZ:AV0Z50520701 Keywords : cell volume regulation * single-cell PCR profiling * ischemia Subject RIV: FH - Neurology

  3. Evaluating the intra- and interobserver reliability of three-dimensional ultrasound and power Doppler angiography (3D-PDA) for assessment of placental volume and vascularity in the second trimester of pregnancy.

    Science.gov (United States)

    Jones, Nia W; Raine-Fenning, Nick J; Mousa, Hatem A; Bradley, Eileen; Bugg, George J

    2011-03-01

    Three-dimensional (3-D) power Doppler angiography (3-D-PDA) allows visualisation of Doppler signals within the placenta and their quantification is possible by the generation of vascular indices by the 4-D View software programme. This study aimed to investigate intra- and interobserver reproducibility of 3-D-PDA analysis of stored datasets at varying gestations with the ultimate goal being to develop a tool for predicting placental dysfunction. Women with an uncomplicated, viable singleton pregnancy were scanned at 12, 16 or 20 weeks gestational age groups. 3-D-PDA datasets acquired of the whole placenta were analysed using the VOCAL software processing tool. Each volume was analysed by three observers twice in the A plane. Intra- and interobserver reliability was assessed by intraclass correlation coefficients (ICCs) and Bland Altman plots. At each gestational age group, 20 low risk women were scanned resulting in 60 datasets in total. The ICC demonstrated a high level of measurement reliability at each gestation with intraobserver values >0.90 and interobserver values of >0.6 for the vascular indices. Bland Altman plots also showed high levels of agreement. Systematic bias was seen at 20 weeks in the vascular indices obtained by different observers. This study demonstrates that 3-D-PDA data can be measured reliably by different observers from stored datasets up to 18 weeks gestation. Measurements become less reliable as gestation advances with bias between observers evident at 20 weeks. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  4. Seismic processing using Parallel 3D FMM

    OpenAIRE

    Borlaug, Idar

    2007-01-01

    This thesis develops and tests 3D Fast Marching Method (FMM) algorithm and apply these to seismic simulations. The FMM is a general method for monotonically advancing fronts, originally developed by Sethian. It calculates the first arrival time for an advancing front or wave. FMM methods are used for a variety of applications including, fatigue cracks in materials, lymph node segmentation in CT images, computing skeletons and centerlines in 3D objects and for finding salt formations in seismi...

  5. Fabrication of 3D Silicon Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; /SINTEF, Oslo; Kenney, C.; Hasi, J.; /SLAC; Da Via, C.; /Manchester U.; Parker, S.I.; /Hawaii U.

    2012-06-06

    Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.

  6. Proposal of a novel ensemble learning based segmentation with a shape prior and its application to spleen segmentation from a 3D abdominal CT volume

    International Nuclear Information System (INIS)

    Shindo, Kiyo; Shimizu, Akinobu; Kobatake, Hidefumi; Nawano, Shigeru; Shinozaki, Kenji

    2010-01-01

    An organ segmentation learned by a conventional ensemble learning algorithm suffers from unnatural errors because each voxel is classified independently in the segmentation process. This paper proposes a novel ensemble learning algorithm that can take into account global shape and location of organs. It estimates the shape and location of an organ from a given image by combining an intermediate segmentation result with a statistical shape model. Once an ensemble learning algorithm could not improve the segmentation performance in the iterative learning process, it estimates the shape and location by finding an optimal model parameter set with maximum degree of correspondence between a statistical shape model and the intermediate segmentation result. Novel weak classifiers are generated based on a signed distance from a boundary of the estimated shape and a distance from a barycenter of the intermediate segmentation result. Subsequently it continues the learning process with the novel weak classifiers. This paper presents experimental results where the proposed ensemble learning algorithm generates a segmentation process that can extract a spleen from a 3D CT image more precisely than a conventional one. (author)

  7. Fast response system for vacuum volume emergency separation

    International Nuclear Information System (INIS)

    Gubrienko, K.I.; Lastochkin, Yu.A.

    1982-01-01

    A system which allows to separate vacuum systems of the magnetic-optic beam channels connected with the accelerator has been worked out for case of emergency environment break through the extraction ''window''. The system, consisting of two valve - gate devices and a control unit, allows one in the emergency case to separate more than 20 m long volume from the accelerator without any pressure changes in the latter one

  8. 3D Surgical Simulation

    OpenAIRE

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2010-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive ...

  9. Evaluation of the anterior ethmoidal artery by 3D dual volume rotational digital subtraction angiography and native multidetector CT with multiplanar reformations. Initial findings.

    Science.gov (United States)

    Pandolfo, Ignazio; Vinci, Sergio; Salamone, Ignazio; Granata, Francesca; Mazziotti, Silvio

    2007-06-01

    Our purpose is to codify the anterior ethmoidal artery (AEA) course and its relationship with adjacent structures. Twenty patients with cerebrovascular disease underwent selective internal carotid dual volume angiography. Fusion of the vascular and bony images was obtained successively on a second console. MDCT of the cranium was performed in all patients. To identify the AEA course, multiplanar CT reformations were obtained. In all cases the entry-point of AEA and its course were identified by means of dual volume angiography. The information was confirmed by MDCT. In a second phase, we studied another 78 patients affected by inflammatory disease and polyposis only by means of MDCT, in order to confirm the previous data obtained by comparison between angiography and MDCT. In this second phase, 110/156 vessels were indirectly detected by means of visualization of the ethmoidal entry point. In the remaining cases, AEA was directly shown due to integrity of the thin ethmoidal bone lamellae or bony canal. Dual volume angiography is essential to identify the course of the AEA (standard of reference for the interpretation of CT). In patients with benign rhinosinusal pathology, where invasivity techniques are not justified, MPR reconstructions were of pivotal importance in the evaluation of the course of the artery with particular reference to its relationship with the frontal recess.

  10. Tangible 3D Modelling

    DEFF Research Database (Denmark)

    Hejlesen, Aske K.; Ovesen, Nis

    2012-01-01

    This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through...... facilitated discussions during the course as well as through a survey distributed to the participating students. The analysis of the experiences shows a mixed picture consisting of both benefits and limits to the experimental technique. A discussion about the applicability of the technique and about...

  11. Urbanisation and 3d Spatial - a Geometric Approach

    Science.gov (United States)

    Duncan, E. E.; Rahman, A. Abdul

    2013-09-01

    Urbanisation creates immense competition for space, this may be attributed to an increase in population owing to domestic and external tourism. Most cities are constantly exploring all avenues in maximising its limited space. Hence, urban or city authorities need to plan, expand and use such three dimensional (3D) space above, on and below the city space. Thus, difficulties in property ownership and the geometric representation of the 3D city space is a major challenge. This research, investigates the concept of representing a geometric topological 3D spatial model capable of representing 3D volume parcels for man-made constructions above and below the 3D surface volume parcel. A review of spatial data models suggests that the 3D TIN (TEN) model is significant and can be used as a unified model. The concepts, logical and physical models of 3D TIN for 3D volumes using tetrahedrons as the base geometry is presented and implemented to show man-made constructions above and below the surface parcel within a user friendly graphical interface. Concepts for 3D topology and 3D analysis are discussed. Simulations of this model for 3D cadastre are implemented. This model can be adopted by most countries to enhance and streamline geometric 3D property ownership for urban centres. 3D TIN concept for spatial modelling can be adopted for the LA_Spatial part of the Land Administration Domain Model (LADM) (ISO/TC211, 2012), this satisfies the concept of 3D volumes.

  12. 3D CT cerebral angiography technique using a 320-detector machine with a time–density curve and low contrast medium volume: Comparison with fixed time delay technique

    International Nuclear Information System (INIS)

    Das, K.; Biswas, S.; Roughley, S.; Bhojak, M.; Niven, S.

    2014-01-01

    Aim: To describe a cerebral computed tomography angiography (CTA) technique using a 320-detector CT machine and a small contrast medium volume (35 ml, 15 ml for test bolus). Also, to compare the quality of these images with that of the images acquired using a larger contrast medium volume (90 or 120 ml) and a fixed time delay (FTD) of 18 s using a 16-detector CT machine. Materials and methods: Cerebral CTA images were acquired using a 320-detector machine by synchronizing the scanning time with the time of peak enhancement as determined from the time–density curve (TDC) using a test bolus dose. The quality of CTA images acquired using this technique was compared with that obtained using a FTD of 18 s (by 16-detector CT), retrospectively. Average densities in four different intracranial arteries, overall opacification of arteries, and the degree of venous contamination were graded and compared. Results: Thirty-eight patients were scanned using the TDC technique and 40 patients using the FTD technique. The arterial densities achieved by the TDC technique were higher (significant for supraclinoid and basilar arteries, p < 0.05). The proportion of images deemed as having “good” arterial opacification was 95% for TDC and 90% for FTD. The degree of venous contamination was significantly higher in images produced by the FTD technique (p < 0.001%). Conclusion: Good diagnostic quality CTA images with significant reduction of venous contamination can be achieved with a low contrast medium dose using a 320-detector machine by coupling the time of data acquisition with the time of peak enhancement

  13. 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.

    Science.gov (United States)

    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.

  14. Sodium fast reactor safety and licensing research plan. Volume I.

    Energy Technology Data Exchange (ETDEWEB)

    Sofu, Tanju (Argonne National Laboratory, Argonne, IL); LaChance, Jeffrey L.; Bari, R. (Brokhaven National Laboratory Upton, NY); Wigeland, Roald (Idaho National Laboratory, Idaho Falls, ID); Denman, Matthew R.; Flanagan, George F. (Oak Ridge National Laboratory, Oak Ridge, TN)

    2012-05-01

    This report proposes potential research priorities for the Department of Energy (DOE) with the intent of improving the licensability of the Sodium Fast Reactor (SFR). In support of this project, five panels were tasked with identifying potential safety-related gaps in available information, data, and models needed to support the licensing of a SFR. The areas examined were sodium technology, accident sequences and initiators, source term characterization, codes and methods, and fuels and materials. It is the intent of this report to utilize a structured and transparent process that incorporates feedback from all interested stakeholders to suggest future funding priorities for the SFR research and development. While numerous gaps were identified, two cross-cutting gaps related to knowledge preservation were agreed upon by all panels and should be addressed in the near future. The first gap is a need to re-evaluate the current procedures for removing the Applied Technology designation from old documents. The second cross-cutting gap is the need for a robust Knowledge Management and Preservation system in all SFR research areas. Closure of these and the other identified gaps will require both a reprioritization of funding within DOE as well as a re-evaluation of existing bureaucratic procedures within the DOE associated with Applied Technology and Knowledge Management.

  15. Sodium fast reactor safety and licensing research plan - Volume I

    International Nuclear Information System (INIS)

    Sofu, Tanju; LaChance, Jeffrey L.; Bari, R.; Wigeland, Roald; Denman, Matthew R.; Flanagan, George F.

    2012-01-01

    This report proposes potential research priorities for the Department of Energy (DOE) with the intent of improving the licensability of the Sodium Fast Reactor (SFR). In support of this project, five panels were tasked with identifying potential safety-related gaps in available information, data, and models needed to support the licensing of a SFR. The areas examined were sodium technology, accident sequences and initiators, source term characterization, codes and methods, and fuels and materials. It is the intent of this report to utilize a structured and transparent process that incorporates feedback from all interested stakeholders to suggest future funding priorities for the SFR research and development. While numerous gaps were identified, two cross-cutting gaps related to knowledge preservation were agreed upon by all panels and should be addressed in the near future. The first gap is a need to re-evaluate the current procedures for removing the Applied Technology designation from old documents. The second cross-cutting gap is the need for a robust Knowledge Management and Preservation system in all SFR research areas. Closure of these and the other identified gaps will require both a reprioritization of funding within DOE as well as a re-evaluation of existing bureaucratic procedures within the DOE associated with Applied Technology and Knowledge Management.

  16. Analysis of 3-D images

    Science.gov (United States)

    Wani, M. Arif; Batchelor, Bruce G.

    1992-03-01

    Deriving generalized representation of 3-D objects for analysis and recognition is a very difficult task. Three types of representations based on type of an object is used in this paper. Objects which have well-defined geometrical shapes are segmented by using a fast edge region based segmentation technique. The segmented image is represented by plan and elevation of each part of the object if the object parts are symmetrical about their central axis. The plan and elevation concept enables representing and analyzing such objects quickly and efficiently. The second type of representation is used for objects having parts which are not symmetrical about their central axis. The segmented surface patches of such objects are represented by the 3-D boundary and the surface features of each segmented surface. Finally, the third type of representation is used for objects which don't have well-defined geometrical shapes (for example a loaf of bread). These objects are represented and analyzed from its features which are derived using a multiscale contour based technique. Anisotropic Gaussian smoothing technique is introduced to segment the contours at various scales of smoothing. A new merging technique is used which enables getting the current best estimate of break points at each scale. This new technique enables elimination of loss of accuracy of localization effects at coarser scales without using scale space tracking approach.

  17. 3D Surgical Simulation

    Science.gov (United States)

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  18. Multifractal modelling and 3D lacunarity analysis

    International Nuclear Information System (INIS)

    Hanen, Akkari; Imen, Bhouri; Asma, Ben Abdallah; Patrick, Dubois; Hedi, Bedoui Mohamed

    2009-01-01

    This study presents a comparative evaluation of lacunarity of 3D grey level models with different types of inhomogeneity. A new method based on the 'Relative Differential Box Counting' was developed to estimate the lacunarity features of grey level volumes. To validate our method, we generated a set of 3D grey level multifractal models with random, anisotropic and hierarchical properties. Our method gives a lacunarity measurement correlated with the theoretical one and allows a better model classification compared with a classical approach.

  19. Visual comfort of 3-D TV : models and measurements

    NARCIS (Netherlands)

    Lambooij, M.T.M.

    2012-01-01

    The embracing of 3-D movies by Hollywood and fast LCD panels finally enable the home consumer market to start successful campaigns to get 3-D movies and games in the comfort of the living room. By introducing three-dimensional television (3-D TV) and its desktop-counterpart for gaming and internet

  20. Semi- and virtual 3D dosimetry in clinical practice

    DEFF Research Database (Denmark)

    Korreman, S. S.

    2013-01-01

    In this review, 3D dosimetry is divided in three categories; "true" 3D, semi-3D and virtual 3D. Virtual 3D involves the use of measurement arrays either before or after beam entry in the patient/phantom, whereas semi-3D involves use of measurement arrays in phantoms mimicking the patient. True 3D...... involves the measurement of dose in a volume mimicking the patient.There are different advantages and limitations of all three categories and of systems within these categories. Choice of measurement method in a given case depends on the aim of the measurement, and examples are given of verification...... measurements with various aims....

  1. Towards large volume big divisor D3/D7 " μ-split supersymmetry" and Ricci-flat Swiss-cheese metrics, and dimension-six neutrino mass operators

    Science.gov (United States)

    Dhuria, Mansi; Misra, Aalok

    2012-02-01

    We show that it is possible to realize a " μ-split SUSY" scenario (Cheng and Cheng, 2005) [1] in the context of large volume limit of type IIB compactifications on Swiss-cheese Calabi-Yau orientifolds in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of μ-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the three-body decays of the gluino into either a quark, a squark and a neutralino or a quark, squark and goldstino, as well as two-body decays of the gluino into either a neutralino and a gluon or a goldstino and a gluon. Guided by the geometric Kähler potential for Σ obtained in Misra and Shukla (2010) [2] based on GLSM techniques, and the Donaldson's algorithm (Barun et al., 2008) [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in Misra and Shukla (2011) [4] pertaining to our proposed metric for the full Swiss-cheese Calabi-Yau (the geometric Kähler potential being needed to be included in the full moduli space Kähler potential in the presence of the mobile space-time filling D3-brane), but for simplicity of calculation, close to the big divisor, which is Ricci-flat in the large volume limit. Also, as an application of the one-loop RG flow solution for the higgsino mass parameter, we show that the contribution to the neutrino masses at the EW scale from dimension-six operators arising from the Kähler potential, is suppressed relative to the Weinberg-type dimension-five operators.

  2. High-risk clinical target volume delineation in CT-guided cervical cancer brachytherapy - Impact of information from FIGO stage with or without systematic inclusion of 3D documentation of clinical gynecological examination

    Energy Technology Data Exchange (ETDEWEB)

    Hegazy, Neamat [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Dept. of Clinical Oncology, Medical Univ. of Alexandria, Alexandria (Egypt); Poetter Rickard; Kirisits, Christian [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria); Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology, Medical Univ. Vienna (Austria); Berger, Daniel; Federico, Mario; Sturdza, Alina; Nesvacil, Nicole [Dept. of Radiotherapy, Comprehensive Cancer Centre Vienna, Medical Univ. of Vienna, Vienna (Austria)], e-mail: nicole.nesvacil@meduniwien.ac.at

    2013-10-15

    Purpose: The aim of the study was to improve computed tomography (CT)-based high-risk clinical target volume (HR CTV) delineation protocols for cervix cancer patients, in settings without any access to magnetic resonance imaging (MRI) at the time of brachytherapy. Therefore the value of a systematic integration of comprehensive three-dimensional (3D) documentation of repetitive gynecological examination for CT-based HR CTV delineation protocols, in addition to information from FIGO staging, was investigated. In addition to a comparison between reference MRI contours and two different CT-based contouring methods (using complementary information from FIGO staging with or without additional 3D clinical drawings), the use of standardized uterine heights was also investigated. Material and methods: Thirty-five cervix cancer patients with CT- and MR-images and 3D clinical drawings at time of diagnosis and brachytherapy were included. HR CTV{sub stage} was based on CT information and FIGO stage. HR CTV{sub stage} {sub +3Dclin} was contoured on CT using FIGO stage and 3D clinical drawing. Standardized HR CTV heights were: 1/1, 2/3 and 1/2 of uterine height. MRI-based HR CTV was delineated independently. Resulting widths, thicknesses, heights, and volumes of HR CTV{sub stage}, HR CTV{sub stage+3Dclin} and MRI-based HR CTV contours were compared. Results: The overall normalized volume ratios (mean{+-}SD of CT/MRI{sub ref} volume) of HR CTV{sub stage} and HR{sub stage+3Dclin} were 2.6 ({+-}0.6) and 2.1 ({+-}0.4) for 1/1 and 2.3 ({+-}0.5) and 1.8 ({+-}0.4), for 2/3, and 1.9 ({+-}0.5) and 1.5 ({+-}0.3), for 1/2 of uterine height. The mean normalized widths were 1.5{+-}0.2 and 1.2{+-}0.2 for HR CTV{sub stage} and HR CTV{sub stage+3Dclin}, respectively (p < 0.05). The mean normalized heights for HR CTV{sub stage} and HR CTV{sub stage+3Dclin} were both 1.7{+-}0.4 for 1/1 (p < 0.05.), 1.3{+-}0.3 for 2/3 (p < 0.05) and 1.1{+-}0.3 for 1/2 of uterine height. Conclusion: CT-based HR

  3. Flat-Panel Detector—Based Volume Computed Tomography: A Novel 3D Imaging Technique to Monitor Osteolytic Bone Lesions in a Mouse Tumor Metastasis Model

    Directory of Open Access Journals (Sweden)

    Jeannine Missbach-Guentner

    2007-09-01

    Full Text Available Skeletal metastasis is an important cause of mortality in patients with breast cancer. Hence, animal models, in combination with various imaging techniques, are in high demand for preclinical assessment of novel therapies. We evaluated the applicability of flat-panel volume computed tomography (fpVCT to noninvasive detection of osteolytic bone metastases that develop in severe immunodeficient mice after intracardial injection of MDA-MB-231 breast cancer cells. A single fpVCT scan at 200-wm isotropic resolution was employed to detect osteolysis within the entire skeleton. Osteolytic lesions identified by fpVCT correlated with Faxitron X-ray analysis and were subsequently confirmed by histopathological examination. Isotropic three-dimensional image data sets obtained by fpVCT were the basis for the precise visualization of the extent of the lesion within the cortical bone and for the measurement of bone loss. Furthermore, fpVCT imaging allows continuous monitoring of growth kinetics for each metastatic site and visualization of lesions in more complex regions of the skeleton, such as the skull. Our findings suggest that fpVCT is a powerful tool that can be used to monitor the occurrence and progression of osteolytic lesions in vivo and can be further developed to monitor responses to antimetastatic therapies over the course of the disease.

  4. Towards Large Volume Big Divisor D3-D7 "mu-Split Supersymmetry" and Ricci-Flat Swiss-Cheese Metrics, and Dimension-Six Neutrino Mass Operators

    CERN Document Server

    Dhuria, Mansi

    2012-01-01

    We show that it is possible to realize a "mu-split SUSY" scenario [1] in the context of large volume limit of type IIB compactifications on Swiss-Cheese Calabi-Yau's in the presence of a mobile space-time filling D3-brane and a (stack of) D7-brane(s) wrapping the "big" divisor Sigma_B. For this, we investigate the possibility of getting one Higgs to be light while other to be heavy in addition to a heavy Higgsino mass parameter. Further, we examine the existence of long lived gluino that manifests one of the major consequences of mu-split SUSY scenario, by computing its decay width as well as lifetime corresponding to the 3-body decays of the gluino into a quark, a squark and a neutralino or Goldstino, as well as 2-body decays of the gluino into either a neutralino or a Goldstino and a gluon. Guided by the geometric Kaehler potential for Sigma_B obtained in [2] based on GLSM techniques, and the Donaldson's algorithm [3] for obtaining numerically a Ricci-flat metric, we give details of our calculation in [4] p...

  5. Localization of liver tumors in freehand 3D laparoscopic ultrasound

    Science.gov (United States)

    Shahin, O.; Martens, V.; Besirevic, A.; Kleemann, M.; Schlaefer, A.

    2012-02-01

    The aim of minimally invasive laparoscopic liver interventions is to completely resect or ablate tumors while minimizing the trauma caused by the operation. However, restrictions such as limited field of view and reduced depth perception can hinder the surgeon's capabilities to precisely localize the tumor. Typically, preoperative data is acquired to find the tumor(s) and plan the surgery. Nevertheless, determining the precise position of the tumor is required, not only before but also during the operation. The standard use of ultrasound in hepatic surgery is to explore the liver and identify tumors. Meanwhile, the surgeon mentally builds a 3D context to localize tumors. This work aims to upgrade the use of ultrasound in laparoscopic liver surgery. We propose an approach to segment and localize tumors intra-operatively in 3D ultrasound. We reconstruct a 3D laparoscopic ultrasound volume containing a tumor. The 3D image is then preprocessed and semi-automatically segmented using a level set algorithm. During the surgery, for each subsequent reconstructed volume, a fast update of the tumor position is accomplished via registration using the previously segmented and localized tumor as a prior knowledge. The approach was tested on a liver phantom with artificial tumors. The tumors were localized in approximately two seconds with a mean error of less than 0.5 mm. The strengths of this technique are that it can be performed intra-operatively, it helps the surgeon to accurately determine the location, shape and volume of the tumor, and it is repeatable throughout the operation.