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Sample records for 4d ml-em reconstruction

  1. A tailored ML-EM algorithm for reconstruction of truncated projection data using few view angles

    NASA Astrophysics Data System (ADS)

    Mao, Yanfei; Zeng, Gengsheng L.

    2013-06-01

    Dedicated cardiac single photon emission computed tomography (SPECT) systems have the advantage of high speed and sensitivity at no loss, or even a gain, in resolution. The potential drawbacks of these dedicated systems are data truncation by the small field of view (FOV) and the lack of view angles. Serious artifacts, including streaks outside the FOV and distortion in the FOV, are introduced to the reconstruction when using the traditional emission data maximum-likelihood expectation-maximization (ML-EM) algorithm to reconstruct images from the truncated data with a small number of views. In this note, we propose a tailored ML-EM algorithm to suppress the artifacts caused by data truncation and insufficient angular sampling by reducing the image updating step sizes for the pixels outside the FOV. As a consequence, the convergence speed for the pixels outside the FOV is decelerated. We applied the proposed algorithm to truncated analytical data, Monte Carlo simulation data and real emission data with different numbers of views. The computer simulation results show that the tailored ML-EM algorithm outperforms the conventional ML-EM algorithm in terms of streak artifacts and distortion suppression for reconstruction from truncated projection data with a small number of views.

  2. Constrained reconstructions for 4D intervention guidance.

    PubMed

    Kuntz, J; Flach, B; Kueres, R; Semmler, W; Kachelriess, M; Bartling, S

    2013-05-21

    Image-guided interventions are an increasingly important part of clinical minimally invasive procedures. However, up to now they cannot be performed under 4D (3D + time) guidance due to the exceedingly high x-ray dose. In this work we investigate the applicability of compressed sensing reconstructions for highly undersampled CT datasets combined with the incorporation of prior images in order to yield low dose 4D intervention guidance. We present a new reconstruction scheme prior image dynamic interventional CT (PrIDICT) that accounts for specific image features in intervention guidance and compare it to PICCS and ASD-POCS. The optimal parameters for the dose per projection and the numbers of projections per reconstruction are determined in phantom simulations and measurements. In vivo experiments in six pigs are performed in a cone-beam CT; measured doses are compared to current gold-standard intervention guidance represented by a clinical fluoroscopy system. Phantom studies show maximum image quality for identical overall doses in the range of 14 to 21 projections per reconstruction. In vivo studies reveal that interventional materials can be followed in 4D visualization and that PrIDICT, compared to PICCS and ASD-POCS, shows superior reconstruction results and fewer artifacts in the periphery with dose in the order of biplane fluoroscopy. These results suggest that 4D intervention guidance can be realized with today's flat detector and gantry systems using the herein presented reconstruction scheme.

  3. Constrained reconstructions for 4D intervention guidance

    NASA Astrophysics Data System (ADS)

    Kuntz, J.; Flach, B.; Kueres, R.; Semmler, W.; Kachelrieß, M.; Bartling, S.

    2013-05-01

    Image-guided interventions are an increasingly important part of clinical minimally invasive procedures. However, up to now they cannot be performed under 4D (3D + time) guidance due to the exceedingly high x-ray dose. In this work we investigate the applicability of compressed sensing reconstructions for highly undersampled CT datasets combined with the incorporation of prior images in order to yield low dose 4D intervention guidance. We present a new reconstruction scheme prior image dynamic interventional CT (PrIDICT) that accounts for specific image features in intervention guidance and compare it to PICCS and ASD-POCS. The optimal parameters for the dose per projection and the numbers of projections per reconstruction are determined in phantom simulations and measurements. In vivo experiments in six pigs are performed in a cone-beam CT; measured doses are compared to current gold-standard intervention guidance represented by a clinical fluoroscopy system. Phantom studies show maximum image quality for identical overall doses in the range of 14 to 21 projections per reconstruction. In vivo studies reveal that interventional materials can be followed in 4D visualization and that PrIDICT, compared to PICCS and ASD-POCS, shows superior reconstruction results and fewer artifacts in the periphery with dose in the order of biplane fluoroscopy. These results suggest that 4D intervention guidance can be realized with today’s flat detector and gantry systems using the herein presented reconstruction scheme.

  4. 4-D reconstruction for dynamic fluorescence diffuse optical tomography.

    PubMed

    Liu, Xin; Zhang, Bin; Luo, Jianwen; Bai, Jing

    2012-11-01

    Dynamic fluorescence diffuse optical tomography (FDOT) is important for the research of drug delivery, medical diagnosis and treatment. Conventionally, dynamic tomographic images are reconstructed frame by frame, independently. This approach fails to account for the temporal correlations in measurement data. Ideally, the entire image sequence should be considered as a whole and a four-dimensional (4-D) reconstruction should be performed. However, the fully 4-D reconstruction is computationally intensive. In this paper, we propose a new 4-D reconstruction approach for dynamic FDOT, which is achieved by applying a temporal Karhunen-Loève (KL) transformation to the imaging equation. By taking advantage of the decorrelation and compression properties of the KL transformation, the complex 4-D optical reconstruction problem is greatly simplified. To evaluate the performance of the method, simulation, phantom, and in vivo experiments (N=7) are performed on a hybrid FDOT/x-ray computed tomography imaging system. The experimental results indicate that the reconstruction images obtained by the KL method provide good reconstruction quality. Additionally, by discarding high-order KL components, the computation time involved with fully 4-D reconstruction can be greatly reduced in contrast to the conventional frame-by-frame reconstruction.

  5. 4D reconstruction of the past

    NASA Astrophysics Data System (ADS)

    Doulamis, Anastasios; Ioannides, Marinos; Doulamis, Nikolaos; Hadjiprocopis, Andreas; Fritsch, Dieter; Balet, Olivier; Julien, Martine; Protopapadakis, Eftychios; Makantasis, Kostas; Weinlinger, Guenther; Johnsons, Paul S.; Klein, Michael; Fellner, Dieter; Stork, Andre; Santos, Pedro

    2013-08-01

    One of the main characteristics of the Internet era we are living in, is the free and online availability of a huge amount of data. This data is of varied reliability and accuracy and exists in various forms and formats. Often, it is cross-referenced and linked to other data, forming a nexus of text, images, animation and audio enabled by hypertext and, recently, by the Web3.0 standard. Search engines can search text for keywords using algorithms of varied intelligence and with limited success. Searching images is a much more complex and computationally intensive task but some initial steps have already been made in this direction, mainly in face recognition. This paper aims to describe our proposed pipeline for integrating data available on Internet repositories and social media, such as photographs, animation and text to produce 3D models of archaeological monuments as well as enriching multimedia of cultural / archaeological interest with metadata and harvesting the end products to EUROPEANA. Our main goal is to enable historians, architects, archaeologists, urban planners and affiliated professionals to reconstruct views of historical monuments from thousands of images floating around the web.

  6. Range Condition and ML-EM Checkerboard Artifacts

    PubMed Central

    You, Jiangsheng; Wang, Jing; Liang, Zhengrong

    2007-01-01

    The expectation maximization (EM) algorithm for the maximum likelihood (ML) image reconstruction criterion generates severe checkerboard artifacts in the presence of noise. A classical remedy is to impose an a priori constraint for a penalized ML or maximum a posteriori probability solution. The penalty reduces the checkerboard artifacts and also introduces uncertainty because a priori information is usually unknown in clinic. Recent theoretical investigation reveals that the noise can be divided into two components: one is called null-space noise and the other is range-space noise. The null-space noise can be numerically estimated using filtered backprojection (FBP) algorithm. By the FBP algorithm, the null-space noise annihilates in the reconstruction while the range-space noise propagates into the reconstructed image. The aim of this work is to investigate the relation between the null-space noise and the checkerboard artifacts in the ML-EM reconstruction from noisy projection data. Our study suggests that removing the null-space noise from the projection data could improve the signal-to-noise ratio of the projection data and, therefore, reduce the checkerboard artifacts in the ML-EM reconstructed images. This study reveals an in-depth understanding of the different noise propagations in analytical and iterative image reconstructions, which may be useful to single photon emission computed tomography, where the noise has been a major factor for image degradation. The reduction of the ML-EM checkerboard artifacts by removing the null-space noise avoids the uncertainty of using a priori penalty. PMID:18449363

  7. 4D RECONSTRUCTIONS FROM LOW-COUNT SPECT DATA USING DEFORMABLE MODELS WITH SMOOTH INTERIOR INTENSITY VARIATIONS

    SciTech Connect

    G. S. CUNNINGHAM; A. LEHOVICH

    2000-01-01

    The Bayes Inference Engine (BIE) has been used to perform a 4D reconstruction of a first-pass radiotracer bolus distribution inside a CardioWest Total Artificial Heart, imaged with the University of Arizona's FastSPECT system. The BIE estimates parameter values that define the 3D model of the radiotracer distribution at each of 41 times spanning about two seconds. The 3D models have two components: a closed surface, composed of hi-quadratic Bezier triangular surface patches, that defines the interface between the part of the blood pool that contains radiotracer and the part that contains no radiotracer, and smooth voxel-to-voxel variations in intensity within the closed surface. Ideally, the surface estimates the ventricular wall location where the bolus is infused throughout the part of the blood pool contained by the right ventricle. The voxel-to-voxel variations are needed to model an inhomogeneously-mixed bolus. Maximum a posterior (MAP) estimates of the Bezier control points and voxel values are obtained for each time frame. We show new reconstructions using the Bezier surface models, and discuss estimates of ventricular volume as a function of time, ejection fraction, and wall motion. The computation time for our reconstruction process, which directly estimates complex 3D model parameters from the raw data, is performed in a time that is competitive with more traditional voxel-based methods (ML-EM, e.g.).

  8. Whole-body direct 4D parametric PET imaging employing nested generalized Patlak expectation–maximization reconstruction

    NASA Astrophysics Data System (ADS)

    Karakatsanis, Nicolas A.; Casey, Michael E.; Lodge, Martin A.; Rahmim, Arman; Zaidi, Habib

    2016-08-01

    Whole-body (WB) dynamic PET has recently demonstrated its potential in translating the quantitative benefits of parametric imaging to the clinic. Post-reconstruction standard Patlak (sPatlak) WB graphical analysis utilizes multi-bed multi-pass PET acquisition to produce quantitative WB images of the tracer influx rate K i as a complimentary metric to the semi-quantitative standardized uptake value (SUV). The resulting K i images may suffer from high noise due to the need for short acquisition frames. Meanwhile, a generalized Patlak (gPatlak) WB post-reconstruction method had been suggested to limit K i bias of sPatlak analysis at regions with non-negligible 18F-FDG uptake reversibility; however, gPatlak analysis is non-linear and thus can further amplify noise. In the present study, we implemented, within the open-source software for tomographic image reconstruction platform, a clinically adoptable 4D WB reconstruction framework enabling efficient estimation of sPatlak and gPatlak images directly from dynamic multi-bed PET raw data with substantial noise reduction. Furthermore, we employed the optimization transfer methodology to accelerate 4D expectation–maximization (EM) convergence by nesting the fast image-based estimation of Patlak parameters within each iteration cycle of the slower projection-based estimation of dynamic PET images. The novel gPatlak 4D method was initialized from an optimized set of sPatlak ML-EM iterations to facilitate EM convergence. Initially, realistic simulations were conducted utilizing published 18F-FDG kinetic parameters coupled with the XCAT phantom. Quantitative analyses illustrated enhanced K i target-to-background ratio (TBR) and especially contrast-to-noise ratio (CNR) performance for the 4D versus the indirect methods and static SUV. Furthermore, considerable convergence acceleration was observed for the nested algorithms involving 10–20 sub-iterations. Moreover, systematic reduction in K i % bias and improved TBR were

  9. Whole-body direct 4D parametric PET imaging employing nested generalized Patlak expectation-maximization reconstruction

    NASA Astrophysics Data System (ADS)

    Karakatsanis, Nicolas A.; Casey, Michael E.; Lodge, Martin A.; Rahmim, Arman; Zaidi, Habib

    2016-08-01

    Whole-body (WB) dynamic PET has recently demonstrated its potential in translating the quantitative benefits of parametric imaging to the clinic. Post-reconstruction standard Patlak (sPatlak) WB graphical analysis utilizes multi-bed multi-pass PET acquisition to produce quantitative WB images of the tracer influx rate K i as a complimentary metric to the semi-quantitative standardized uptake value (SUV). The resulting K i images may suffer from high noise due to the need for short acquisition frames. Meanwhile, a generalized Patlak (gPatlak) WB post-reconstruction method had been suggested to limit K i bias of sPatlak analysis at regions with non-negligible 18F-FDG uptake reversibility; however, gPatlak analysis is non-linear and thus can further amplify noise. In the present study, we implemented, within the open-source software for tomographic image reconstruction platform, a clinically adoptable 4D WB reconstruction framework enabling efficient estimation of sPatlak and gPatlak images directly from dynamic multi-bed PET raw data with substantial noise reduction. Furthermore, we employed the optimization transfer methodology to accelerate 4D expectation-maximization (EM) convergence by nesting the fast image-based estimation of Patlak parameters within each iteration cycle of the slower projection-based estimation of dynamic PET images. The novel gPatlak 4D method was initialized from an optimized set of sPatlak ML-EM iterations to facilitate EM convergence. Initially, realistic simulations were conducted utilizing published 18F-FDG kinetic parameters coupled with the XCAT phantom. Quantitative analyses illustrated enhanced K i target-to-background ratio (TBR) and especially contrast-to-noise ratio (CNR) performance for the 4D versus the indirect methods and static SUV. Furthermore, considerable convergence acceleration was observed for the nested algorithms involving 10-20 sub-iterations. Moreover, systematic reduction in K i % bias and improved TBR were

  10. Whole-body direct 4D parametric PET imaging employing nested generalized Patlak expectation-maximization reconstruction.

    PubMed

    Karakatsanis, Nicolas A; Casey, Michael E; Lodge, Martin A; Rahmim, Arman; Zaidi, Habib

    2016-08-01

    Whole-body (WB) dynamic PET has recently demonstrated its potential in translating the quantitative benefits of parametric imaging to the clinic. Post-reconstruction standard Patlak (sPatlak) WB graphical analysis utilizes multi-bed multi-pass PET acquisition to produce quantitative WB images of the tracer influx rate K i as a complimentary metric to the semi-quantitative standardized uptake value (SUV). The resulting K i images may suffer from high noise due to the need for short acquisition frames. Meanwhile, a generalized Patlak (gPatlak) WB post-reconstruction method had been suggested to limit K i bias of sPatlak analysis at regions with non-negligible (18)F-FDG uptake reversibility; however, gPatlak analysis is non-linear and thus can further amplify noise. In the present study, we implemented, within the open-source software for tomographic image reconstruction platform, a clinically adoptable 4D WB reconstruction framework enabling efficient estimation of sPatlak and gPatlak images directly from dynamic multi-bed PET raw data with substantial noise reduction. Furthermore, we employed the optimization transfer methodology to accelerate 4D expectation-maximization (EM) convergence by nesting the fast image-based estimation of Patlak parameters within each iteration cycle of the slower projection-based estimation of dynamic PET images. The novel gPatlak 4D method was initialized from an optimized set of sPatlak ML-EM iterations to facilitate EM convergence. Initially, realistic simulations were conducted utilizing published (18)F-FDG kinetic parameters coupled with the XCAT phantom. Quantitative analyses illustrated enhanced K i target-to-background ratio (TBR) and especially contrast-to-noise ratio (CNR) performance for the 4D versus the indirect methods and static SUV. Furthermore, considerable convergence acceleration was observed for the nested algorithms involving 10-20 sub-iterations. Moreover, systematic reduction in K i % bias and improved TBR were

  11. A sinogram warping strategy for pre-reconstruction 4D PET optimization.

    PubMed

    Gianoli, Chiara; Riboldi, Marco; Fontana, Giulia; Kurz, Christopher; Parodi, Katia; Baroni, Guido

    2016-03-01

    A novel strategy for 4D PET optimization in the sinogram domain is proposed, aiming at motion model application before image reconstruction ("sinogram warping" strategy). Compared to state-of-the-art 4D-MLEM reconstruction, the proposed strategy is able to optimize the image SNR, avoiding iterative direct and inverse warping procedures, which are typical of the 4D-MLEM algorithm. A full-count statistics sinogram of the motion-compensated 4D PET reference phase is generated by warping the sinograms corresponding to the different PET phases. This is achieved relying on a motion model expressed in the sinogram domain. The strategy was tested on the anthropomorphic 4D PET-CT NCAT phantom in comparison with the 4D-MLEM algorithm, with particular reference to robustness to PET-CT co-registrations artefacts. The MLEM reconstruction of the warped sinogram according to the proposed strategy exhibited better accuracy (up to +40.90 % with respect to the ideal value), whereas images reconstructed according to the 4D-MLEM reconstruction resulted in less noisy (down to -26.90 % with respect to the ideal value) but more blurred. The sinogram warping strategy demonstrates advantages with respect to 4D-MLEM algorithm. These advantages are paid back by introducing approximation of the deformation field, and further efforts are required to mitigate the impact of such an approximation in clinical 4D PET reconstruction.

  12. Simultaneous motion estimation and image reconstruction (SMEIR) for 4D cone-beam CT

    SciTech Connect

    Wang, Jing; Gu, Xuejun

    2013-10-15

    Purpose: Image reconstruction and motion model estimation in four-dimensional cone-beam CT (4D-CBCT) are conventionally handled as two sequential steps. Due to the limited number of projections at each phase, the image quality of 4D-CBCT is degraded by view aliasing artifacts, and the accuracy of subsequent motion modeling is decreased by the inferior 4D-CBCT. The objective of this work is to enhance both the image quality of 4D-CBCT and the accuracy of motion model estimation with a novel strategy enabling simultaneous motion estimation and image reconstruction (SMEIR).Methods: The proposed SMEIR algorithm consists of two alternating steps: (1) model-based iterative image reconstruction to obtain a motion-compensated primary CBCT (m-pCBCT) and (2) motion model estimation to obtain an optimal set of deformation vector fields (DVFs) between the m-pCBCT and other 4D-CBCT phases. The motion-compensated image reconstruction is based on the simultaneous algebraic reconstruction technique (SART) coupled with total variation minimization. During the forward- and backprojection of SART, measured projections from an entire set of 4D-CBCT are used for reconstruction of the m-pCBCT by utilizing the updated DVF. The DVF is estimated by matching the forward projection of the deformed m-pCBCT and measured projections of other phases of 4D-CBCT. The performance of the SMEIR algorithm is quantitatively evaluated on a 4D NCAT phantom. The quality of reconstructed 4D images and the accuracy of tumor motion trajectory are assessed by comparing with those resulting from conventional sequential 4D-CBCT reconstructions (FDK and total variation minimization) and motion estimation (demons algorithm). The performance of the SMEIR algorithm is further evaluated by reconstructing a lung cancer patient 4D-CBCT.Results: Image quality of 4D-CBCT is greatly improved by the SMEIR algorithm in both phantom and patient studies. When all projections are used to reconstruct a 3D-CBCT by FDK, motion

  13. Simultaneous motion estimation and image reconstruction (SMEIR) for 4D cone-beam CT

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Gu, Xuejun

    2014-03-01

    Image reconstruction and motion model estimation in four dimensional cone-beam CT (4D-CBCT) are conventionally handled as two sequential steps. Due to the limited number of projections at each phase, the image quality of 4D-CBCT is degraded by view aliasing artifacts, and the accuracy of subsequent motion modeling is decreased by the inferior 4DCBCT. The objective of this work is to enhance both the image quality of 4D-CBCT and the accuracy of motion model estimation with a novel strategy enabling simultaneous motion estimation and image reconstruction (SMEIR). The proposed SMEIR algorithm consists of two alternating steps: 1) model-based iterative image reconstruction to obtain a motion-compensated primary CBCT (m-pCBCT) and 2) motion model estimation to obtain an optimal set of deformation vector fields (DVFs) between the m-pCBCT and other 4D-CBCT phases. The motion-compensated image reconstruction is based on the simultaneous algebraic reconstruction (SART) technique coupled with total variation minimization. During the forward- and back-projection of SART, measured projections from an entire set of 4D-CBCT are used for reconstruction of the m-pCBCT by utilizing the updated DVF. The DVF is estimated by matching the forward projection of the deformed m-pCBCT and measured projections of other phases of 4D-CBCT. The performance of the SMEIR algorithm is quantitatively evaluated on a 4D NCAT phantom. The SMEIR algorithm improves image reconstruction accuracy of 4D-CBCT and tumor motion trajectory estimation accuracy as compared to conventional sequential 4D-CBCT reconstruction and motion estimation.

  14. Fully 4D list-mode reconstruction applied to respiratory-gated PET scans

    NASA Astrophysics Data System (ADS)

    Grotus, N; Reader, A J; Stute, S; Rosenwald, J C; Giraud, P; Buvat, I

    2009-03-01

    18F-fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) is one of the most sensitive and specific imaging modalities for the diagnosis of non-small cell lung cancer. A drawback of PET is that it requires several minutes of acquisition per bed position, which results in images being affected by respiratory blur. Respiratory gating techniques have been developed to deal with respiratory motion in the PET images. However, these techniques considerably increase the level of noise in the reconstructed images unless the acquisition time is increased. The aim of this paper is to evaluate a four-dimensional (4D) image reconstruction algorithm that combines the acquired events in all the gates whilst preserving the motion deblurring. This algorithm was compared to classic ordered subset expectation maximization (OSEM) reconstruction of gated and non-gated images, and to temporal filtering of gated images reconstructed with OSEM. Two datasets were used for comparing the different reconstruction approaches: one involving the NEMA IEC/2001 body phantom in motion, the other obtained using Monte-Carlo simulations of the NCAT breathing phantom. Results show that 4D reconstruction reaches a similar performance in terms of the signal-to-noise ratio (SNR) as non-gated reconstruction whilst preserving the motion deblurring. In particular, 4D reconstruction improves the SNR compared to respiratory-gated images reconstructed with the OSEM algorithm. Temporal filtering of the OSEM-reconstructed images helps improve the SNR, but does not achieve the same performance as 4D reconstruction. 4D reconstruction of respiratory-gated images thus appears as a promising tool to reach the same performance in terms of the SNR as non-gated acquisitions while reducing the motion blur, without increasing the acquisition time.

  15. Improved image quality and computation reduction in 4-D reconstruction of cardiac-gated SPECT images.

    PubMed

    Narayanan, M V; King, M A; Wernick, M N; Byrne, C L; Soares, E J; Pretorius, P H

    2000-05-01

    Spatiotemporal reconstruction of cardiac-gated SPECT images permits us to obtain valuable information related to cardiac function. However, the task of reconstructing this four-dimensional (4-D) data set is computation intensive. Typically, these studies are reconstructed frame-by-frame: a nonoptimal approach because temporal correlations in the signal are not accounted for. In this work, we show that the compression and signal decorrelation properties of the Karhunen-Loève (KL) transform may be used to greatly simplify the spatiotemporal reconstruction problem. The gated projections are first KL transformed in the temporal direction. This results in a sequence of KL-transformed projection images for which the signal components are uncorrelated along the time axis. As a result, the 4-D reconstruction task is simplified to a series of three-dimensional (3-D) reconstructions in the KL domain. The reconstructed KL components are subsequently inverse KL transformed to obtain the entire spatiotemporal reconstruction set. Our simulation and clinical results indicate that KL processing provides image sequences that are less noisy than are conventional frame-by-frame reconstructions. Additionally, by discarding high-order KL components that are dominated by noise, we can achieve savings in computation time because fewer reconstructions are needed in comparison to conventional frame-by-frame reconstructions.

  16. Evaluation of a 4D cone-beam CT reconstruction approach using a simulation framework.

    PubMed

    Hartl, Alexander; Yaniv, Ziv

    2009-01-01

    Current image-guided navigation systems for thoracic abdominal interventions utilize three dimensional (3D) images acquired at breath-hold. As a result they can only provide guidance at a specific point in the respiratory cycle. The intervention is thus performed in a gated manner, with the physician advancing only when the patient is at the same respiratory cycle in which the 3D image was acquired. To enable a more continuous workflow we propose to use 4D image data. We describe an approach to constructing a set of 4D images from a diagnostic CT acquired at breath-hold and a set of intraoperative cone-beam CT (CBCT) projection images acquired while the patient is freely breathing. Our approach is based on an initial reconstruction of a gated 4D CBCT data set. The 3D CBCT images for each respiratory phase are then non-rigidly registered to the diagnostic CT data. Finally the diagnostic CT is deformed based on the registration results, providing a 4D data set with sufficient quality for navigation purposes. In this work we evaluate the proposed reconstruction approach using a simulation framework. A 3D CBCT dataset of an anthropomorphic phantom is deformed using internal motion data acquired from an animal model to create a ground truth 4D CBCT image. Simulated projection images are then created from the 4D image and the known CBCT scan parameters. Finally, the original 3D CBCT and the simulated X-ray images are used as input to our reconstruction method. The resulting 4D data set is then compared to the known ground truth by normalized cross correlation(NCC). We show that the deformed diagnostic CTs are of better quality than the gated reconstructions with a mean NCC value of 0.94 versus a mean 0.81 for the reconstructions. PMID:19964143

  17. Respiratory motion correction in 4D-PET by simultaneous motion estimation and image reconstruction (SMEIR).

    PubMed

    Kalantari, Faraz; Li, Tianfang; Jin, Mingwu; Wang, Jing

    2016-08-01

    In conventional 4D positron emission tomography (4D-PET), images from different frames are reconstructed individually and aligned by registration methods. Two issues that arise with this approach are as follows: (1) the reconstruction algorithms do not make full use of projection statistics; and (2) the registration between noisy images can result in poor alignment. In this study, we investigated the use of simultaneous motion estimation and image reconstruction (SMEIR) methods for motion estimation/correction in 4D-PET. A modified ordered-subset expectation maximization algorithm coupled with total variation minimization (OSEM-TV) was used to obtain a primary motion-compensated PET (pmc-PET) from all projection data, using Demons derived deformation vector fields (DVFs) as initial motion vectors. A motion model update was performed to obtain an optimal set of DVFs in the pmc-PET and other phases, by matching the forward projection of the deformed pmc-PET with measured projections from other phases. The OSEM-TV image reconstruction was repeated using updated DVFs, and new DVFs were estimated based on updated images. A 4D-XCAT phantom with typical FDG biodistribution was generated to evaluate the performance of the SMEIR algorithm in lung and liver tumors with different contrasts and different diameters (10-40 mm). The image quality of the 4D-PET was greatly improved by the SMEIR algorithm. When all projections were used to reconstruct 3D-PET without motion compensation, motion blurring artifacts were present, leading up to 150% tumor size overestimation and significant quantitative errors, including 50% underestimation of tumor contrast and 59% underestimation of tumor uptake. Errors were reduced to less than 10% in most images by using the SMEIR algorithm, showing its potential in motion estimation/correction in 4D-PET. PMID:27385378

  18. Respiratory motion correction in 4D-PET by simultaneous motion estimation and image reconstruction (SMEIR)

    NASA Astrophysics Data System (ADS)

    Kalantari, Faraz; Li, Tianfang; Jin, Mingwu; Wang, Jing

    2016-08-01

    In conventional 4D positron emission tomography (4D-PET), images from different frames are reconstructed individually and aligned by registration methods. Two issues that arise with this approach are as follows: (1) the reconstruction algorithms do not make full use of projection statistics; and (2) the registration between noisy images can result in poor alignment. In this study, we investigated the use of simultaneous motion estimation and image reconstruction (SMEIR) methods for motion estimation/correction in 4D-PET. A modified ordered-subset expectation maximization algorithm coupled with total variation minimization (OSEM-TV) was used to obtain a primary motion-compensated PET (pmc-PET) from all projection data, using Demons derived deformation vector fields (DVFs) as initial motion vectors. A motion model update was performed to obtain an optimal set of DVFs in the pmc-PET and other phases, by matching the forward projection of the deformed pmc-PET with measured projections from other phases. The OSEM-TV image reconstruction was repeated using updated DVFs, and new DVFs were estimated based on updated images. A 4D-XCAT phantom with typical FDG biodistribution was generated to evaluate the performance of the SMEIR algorithm in lung and liver tumors with different contrasts and different diameters (10-40 mm). The image quality of the 4D-PET was greatly improved by the SMEIR algorithm. When all projections were used to reconstruct 3D-PET without motion compensation, motion blurring artifacts were present, leading up to 150% tumor size overestimation and significant quantitative errors, including 50% underestimation of tumor contrast and 59% underestimation of tumor uptake. Errors were reduced to less than 10% in most images by using the SMEIR algorithm, showing its potential in motion estimation/correction in 4D-PET.

  19. Respiratory motion correction in 4D-PET by simultaneous motion estimation and image reconstruction (SMEIR).

    PubMed

    Kalantari, Faraz; Li, Tianfang; Jin, Mingwu; Wang, Jing

    2016-08-01

    In conventional 4D positron emission tomography (4D-PET), images from different frames are reconstructed individually and aligned by registration methods. Two issues that arise with this approach are as follows: (1) the reconstruction algorithms do not make full use of projection statistics; and (2) the registration between noisy images can result in poor alignment. In this study, we investigated the use of simultaneous motion estimation and image reconstruction (SMEIR) methods for motion estimation/correction in 4D-PET. A modified ordered-subset expectation maximization algorithm coupled with total variation minimization (OSEM-TV) was used to obtain a primary motion-compensated PET (pmc-PET) from all projection data, using Demons derived deformation vector fields (DVFs) as initial motion vectors. A motion model update was performed to obtain an optimal set of DVFs in the pmc-PET and other phases, by matching the forward projection of the deformed pmc-PET with measured projections from other phases. The OSEM-TV image reconstruction was repeated using updated DVFs, and new DVFs were estimated based on updated images. A 4D-XCAT phantom with typical FDG biodistribution was generated to evaluate the performance of the SMEIR algorithm in lung and liver tumors with different contrasts and different diameters (10-40 mm). The image quality of the 4D-PET was greatly improved by the SMEIR algorithm. When all projections were used to reconstruct 3D-PET without motion compensation, motion blurring artifacts were present, leading up to 150% tumor size overestimation and significant quantitative errors, including 50% underestimation of tumor contrast and 59% underestimation of tumor uptake. Errors were reduced to less than 10% in most images by using the SMEIR algorithm, showing its potential in motion estimation/correction in 4D-PET.

  20. Respiratory motion correction in 4D-PET by simultaneous motion estimation and image reconstruction (SMEIR)

    NASA Astrophysics Data System (ADS)

    Kalantari, Faraz; Li, Tianfang; Jin, Mingwu; Wang, Jing

    2016-08-01

    In conventional 4D positron emission tomography (4D-PET), images from different frames are reconstructed individually and aligned by registration methods. Two issues that arise with this approach are as follows: (1) the reconstruction algorithms do not make full use of projection statistics; and (2) the registration between noisy images can result in poor alignment. In this study, we investigated the use of simultaneous motion estimation and image reconstruction (SMEIR) methods for motion estimation/correction in 4D-PET. A modified ordered-subset expectation maximization algorithm coupled with total variation minimization (OSEM-TV) was used to obtain a primary motion-compensated PET (pmc-PET) from all projection data, using Demons derived deformation vector fields (DVFs) as initial motion vectors. A motion model update was performed to obtain an optimal set of DVFs in the pmc-PET and other phases, by matching the forward projection of the deformed pmc-PET with measured projections from other phases. The OSEM-TV image reconstruction was repeated using updated DVFs, and new DVFs were estimated based on updated images. A 4D-XCAT phantom with typical FDG biodistribution was generated to evaluate the performance of the SMEIR algorithm in lung and liver tumors with different contrasts and different diameters (10–40 mm). The image quality of the 4D-PET was greatly improved by the SMEIR algorithm. When all projections were used to reconstruct 3D-PET without motion compensation, motion blurring artifacts were present, leading up to 150% tumor size overestimation and significant quantitative errors, including 50% underestimation of tumor contrast and 59% underestimation of tumor uptake. Errors were reduced to less than 10% in most images by using the SMEIR algorithm, showing its potential in motion estimation/correction in 4D-PET.

  1. A hybrid reconstruction algorithm for fast and accurate 4D cone-beam CT imaging

    SciTech Connect

    Yan, Hao; Folkerts, Michael; Jiang, Steve B. E-mail: steve.jiang@UTSouthwestern.edu; Jia, Xun E-mail: steve.jiang@UTSouthwestern.edu; Zhen, Xin; Li, Yongbao; Pan, Tinsu; Cervino, Laura

    2014-07-15

    Purpose: 4D cone beam CT (4D-CBCT) has been utilized in radiation therapy to provide 4D image guidance in lung and upper abdomen area. However, clinical application of 4D-CBCT is currently limited due to the long scan time and low image quality. The purpose of this paper is to develop a new 4D-CBCT reconstruction method that restores volumetric images based on the 1-min scan data acquired with a standard 3D-CBCT protocol. Methods: The model optimizes a deformation vector field that deforms a patient-specific planning CT (p-CT), so that the calculated 4D-CBCT projections match measurements. A forward-backward splitting (FBS) method is invented to solve the optimization problem. It splits the original problem into two well-studied subproblems, i.e., image reconstruction and deformable image registration. By iteratively solving the two subproblems, FBS gradually yields correct deformation information, while maintaining high image quality. The whole workflow is implemented on a graphic-processing-unit to improve efficiency. Comprehensive evaluations have been conducted on a moving phantom and three real patient cases regarding the accuracy and quality of the reconstructed images, as well as the algorithm robustness and efficiency. Results: The proposed algorithm reconstructs 4D-CBCT images from highly under-sampled projection data acquired with 1-min scans. Regarding the anatomical structure location accuracy, 0.204 mm average differences and 0.484 mm maximum difference are found for the phantom case, and the maximum differences of 0.3–0.5 mm for patients 1–3 are observed. As for the image quality, intensity errors below 5 and 20 HU compared to the planning CT are achieved for the phantom and the patient cases, respectively. Signal-noise-ratio values are improved by 12.74 and 5.12 times compared to results from FDK algorithm using the 1-min data and 4-min data, respectively. The computation time of the algorithm on a NVIDIA GTX590 card is 1–1.5 min per phase

  2. Constrain static target kinetic iterative image reconstruction for 4D cardiac CT imaging

    NASA Astrophysics Data System (ADS)

    Alessio, Adam M.; La Riviere, Patrick J.

    2011-03-01

    Iterative image reconstruction offers improved signal to noise properties for CT imaging. A primary challenge with iterative methods is the substantial computation time. This computation time is even more prohibitive in 4D imaging applications, such as cardiac gated or dynamic acquisition sequences. In this work, we propose only updating the time-varying elements of a 4D image sequence while constraining the static elements to be fixed or slowly varying in time. We test the method with simulations of 4D acquisitions based on measured cardiac patient data from a) a retrospective cardiac-gated CT acquisition and b) a dynamic perfusion CT acquisition. We target the kinetic elements with one of two methods: 1) position a circular ROI on the heart, assuming area outside ROI is essentially static throughout imaging time; and 2) select varying elements from the coefficient of variation image formed from fast analytic reconstruction of all time frames. Targeted kinetic elements are updated with each iteration, while static elements remain fixed at initial image values formed from the reconstruction of data from all time frames. Results confirm that the computation time is proportional to the number of targeted elements; our simulations suggest that <30% of elements need to be updated in each frame leading to >3 times reductions in reconstruction time. The images reconstructed with the proposed method have matched mean square error with full 4D reconstruction. The proposed method is amenable to most optimization algorithms and offers the potential for significant computation improvements, which could be traded off for more sophisticated system models or penalty terms.

  3. 4D cone-beam CT reconstruction using multi-organ meshes for sliding motion modeling.

    PubMed

    Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing

    2016-02-01

    A simultaneous motion estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the motion fields. The objective of this work is to improve the computation efficiency and motion estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing model. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and motion. Additionally, the discontinuity in the motion fields between different organs during respiration was explicitly considered in the multi-organ mesh model. This will help with the accurate visualization and motion estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding motion phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp-Davis-Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations.

  4. 4D cone-beam CT reconstruction using multi-organ meshes for sliding motion modeling

    NASA Astrophysics Data System (ADS)

    Zhong, Zichun; Gu, Xuejun; Mao, Weihua; Wang, Jing

    2016-02-01

    A simultaneous motion estimation and image reconstruction (SMEIR) strategy was proposed for 4D cone-beam CT (4D-CBCT) reconstruction and showed excellent results in both phantom and lung cancer patient studies. In the original SMEIR algorithm, the deformation vector field (DVF) was defined on voxel grid and estimated by enforcing a global smoothness regularization term on the motion fields. The objective of this work is to improve the computation efficiency and motion estimation accuracy of SMEIR for 4D-CBCT through developing a multi-organ meshing model. Feature-based adaptive meshes were generated to reduce the number of unknowns in the DVF estimation and accurately capture the organ shapes and motion. Additionally, the discontinuity in the motion fields between different organs during respiration was explicitly considered in the multi-organ mesh model. This will help with the accurate visualization and motion estimation of the tumor on the organ boundaries in 4D-CBCT. To further improve the computational efficiency, a GPU-based parallel implementation was designed. The performance of the proposed algorithm was evaluated on a synthetic sliding motion phantom, a 4D NCAT phantom, and four lung cancer patients. The proposed multi-organ mesh based strategy outperformed the conventional Feldkamp-Davis-Kress, iterative total variation minimization, original SMEIR and single meshing method based on both qualitative and quantitative evaluations.

  5. Spatial-temporal total variation regularization (STTVR) for 4D-CT reconstruction

    NASA Astrophysics Data System (ADS)

    Wu, Haibo; Maier, Andreas; Fahrig, Rebecca; Hornegger, Joachim

    2012-03-01

    Four dimensional computed tomography (4D-CT) is very important for treatment planning in thorax or abdomen area, e.g. for guiding radiation therapy planning. The respiratory motion makes the reconstruction problem illposed. Recently, compressed sensing theory was introduced. It uses sparsity as a prior to solve the problem and improves image quality considerably. However, the images at each phase are reconstructed individually. The correlations between neighboring phases are not considered in the reconstruction process. In this paper, we propose the spatial-temporal total variation regularization (STTVR) method which not only employs the sparsity in the spatial domain but also in the temporal domain. The algorithm is validated with XCAT thorax phantom. The Euclidean norm of the reconstructed image and ground truth is calculated for evaluation. The results indicate that our method improves the reconstruction quality by more than 50% compared to standard ART.

  6. Motion-compensated fully 4D reconstruction of gated cardiac sequences

    NASA Astrophysics Data System (ADS)

    Gravier, Erwan; Yang, Yongyi

    2005-03-01

    In this paper we investigate the benefits of a spatio-temporal approach for reconstruction of cardiac image sequences. We introduce a temporal prior based on motion-compensation to enforce temporal correlations along the curved trajectories that follow the cardiac motion. The image frames in a sequence are reconstructed simultaneously through maximum a posteriori (MAP) estimation. We evaluated the performance of our algorithm using the 4D gated mathematical cardiac-torso (gMCAT) D1.01 phantom to simulate gated SPECT perfusion imaging with Tc-99m-sestamibi. Our experimental results show that the proposed approach could significantly improve the accuracy of reconstructed images without causing cross-frame blurring that may arise form the cardiac motion.

  7. VMAT QA: Measurement-guided 4D dose reconstruction on a patient

    SciTech Connect

    Nelms, Benjamin E.; Opp, Daniel; Robinson, Joshua; Wolf, Theresa K.; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir

    2012-07-15

    Purpose: To develop and validate a volume-modulated arc therapy (VMAT) quality assurance (QA) tool that takes as input a time-resolved, low-density ({approx}10 mm) cylindrical surface dose map from a commercial helical diode array, and outputs a high density, volumetric, time-resolved dose matrix on an arbitrary patient dataset. This first validation study is limited to a homogeneous 'patient.'Methods: A VMAT treatment is delivered to a diode array phantom (ARCCHECK, Sun Nuclear Corp., Melbourne, FL). 3DVH software (Sun Nuclear) derives the high-density volumetric dose using measurement-guided dose reconstruction (MGDR). MGDR cylindrical phantom results are then used to perturb the three-dimensional (3D) treatment planning dose on the patient dataset, producing a semiempirical volumetric dose grid. Four-dimensional (4D) dose reconstruction on the patient is also possible by morphing individual sub-beam doses instead of the composite. For conventional (3D) dose comparison two methods were developed, using the four plans (Multi-Target, C-shape, Mock Prostate, and Head and Neck), including their structures and objectives, from the AAPM TG-119 report. First, 3DVH and treatment planning system (TPS) cumulative point doses were compared to ion chamber in a cube water-equivalent phantom ('patient'). The shape of the phantom is different from the ARCCHECK and furthermore the targets were placed asymmetrically. Second, coronal and sagittal absolute film dose distributions in the cube were compared with 3DVH and TPS. For time-resolved (4D) comparisons, three tests were performed. First, volumetric dose differences were calculated between the 3D MGDR and cumulative time-resolved patient (4D MGDR) dose at the end of delivery, where they ideally should be identical. Second, time-resolved (10 Hz sampling rate) ion chamber doses were compared to cumulative point dose vs time curves from 4D MGDR. Finally, accelerator output was varied to assess the linearity of the 4D MGDR with

  8. Registration based super-resolution reconstruction for lung 4D-CT.

    PubMed

    Wu, Xiuxiu; Xiao, Shan; Zhang, Yu

    2014-01-01

    Lung 4D-CT plays an important role in lung cancer radiotherapy for tumor localization and treatment planning. In lung 4D-CT data, the resolution in the slice direction is often much lower than the in-plane resolution. For multi-plane display, isotropic resolution is necessary, but the commonly used interpolation operation will blur the images. In this paper, we present a registration based method for super resolution enhancement of the 4D-CT multi-plane images. Our working premise is that the low-resolution images of different phases at the corresponding position can be regarded as input "frames" to reconstruct high resolution images. First, we employ the Demons registration algorithm to estimate the motion field between different "frames". Then, the projections onto convex sets (POCS) approach is employed to reconstruction high-resolution lung images. We show that our method can get clearer lung images and enhance image structure, compared with the cubic spline interpolation and back projection method. PMID:25570484

  9. Registration based super-resolution reconstruction for lung 4D-CT.

    PubMed

    Wu, Xiuxiu; Xiao, Shan; Zhang, Yu

    2014-01-01

    Lung 4D-CT plays an important role in lung cancer radiotherapy for tumor localization and treatment planning. In lung 4D-CT data, the resolution in the slice direction is often much lower than the in-plane resolution. For multi-plane display, isotropic resolution is necessary, but the commonly used interpolation operation will blur the images. In this paper, we present a registration based method for super resolution enhancement of the 4D-CT multi-plane images. Our working premise is that the low-resolution images of different phases at the corresponding position can be regarded as input "frames" to reconstruct high resolution images. First, we employ the Demons registration algorithm to estimate the motion field between different "frames". Then, the projections onto convex sets (POCS) approach is employed to reconstruction high-resolution lung images. We show that our method can get clearer lung images and enhance image structure, compared with the cubic spline interpolation and back projection method.

  10. Fully 4D motion-compensated reconstruction of cardiac SPECT images

    NASA Astrophysics Data System (ADS)

    Gravier, Erwan; Yang, Yongyi; King, Michael A.; Jin, Mingwu

    2006-09-01

    In this paper, we investigate the benefits of a spatiotemporal approach for reconstruction of image sequences. In the proposed approach, we introduce a temporal prior in the form of motion compensation to account for the statistical correlations among the frames in a sequence, and reconstruct all the frames collectively as a single function of space and time. The reconstruction algorithm is derived based on the maximum a posteriori estimate, for which the one-step late expectation-maximization algorithm is used. We demonstrated the method in our experiments using simulated single photon emission computed tomography (SPECT) cardiac perfusion images. The four-dimensional (4D) gated mathematical cardiac-torso phantom was used for simulation of gated SPECT perfusion imaging with Tc-99m-sestamibi. In addition to bias-variance analysis and time activity curves, we also used a channelized Hotelling observer to evaluate the detectability of perfusion defects in the reconstructed images. Our experimental results demonstrated that the incorporation of temporal regularization into image reconstruction could significantly improve the accuracy of cardiac images without causing any significant cross-frame blurring that may arise from the cardiac motion. This could lead to not only improved detection of perfusion defects, but also improved reconstruction of the heart wall which is important for functional assessment of the myocardium. This work was supported in part by the National Institutes of Health under grant no HL65425.

  11. Application of adaptive kinetic modelling for bias propagation reduction in direct 4D image reconstruction

    NASA Astrophysics Data System (ADS)

    Kotasidis, F. A.; Matthews, J. C.; Reader, A. J.; Angelis, G. I.; Zaidi, H.

    2014-10-01

    Parametric imaging in thoracic and abdominal PET can provide additional parameters more relevant to the pathophysiology of the system under study. However, dynamic data in the body are noisy due to the limiting counting statistics leading to suboptimal kinetic parameter estimates. Direct 4D image reconstruction algorithms can potentially improve kinetic parameter precision and accuracy in dynamic PET body imaging. However, construction of a common kinetic model is not always feasible and in contrast to post-reconstruction kinetic analysis, errors in poorly modelled regions may spatially propagate to regions which are well modelled. To reduce error propagation from erroneous model fits, we implement and evaluate a new approach to direct parameter estimation by incorporating a recently proposed kinetic modelling strategy within a direct 4D image reconstruction framework. The algorithm uses a secondary more general model to allow a less constrained model fit in regions where the kinetic model does not accurately describe the underlying kinetics. A portion of the residuals then is adaptively included back into the image whilst preserving the primary model characteristics in other well modelled regions using a penalty term that trades off the models. Using fully 4D simulations based on dynamic [15O]H2O datasets, we demonstrate reduction in propagation-related bias for all kinetic parameters. Under noisy conditions, reductions in bias due to propagation are obtained at the cost of increased noise, which in turn results in increased bias and variance of the kinetic parameters. This trade-off reflects the challenge of separating the residuals arising from poor kinetic modelling fits from the residuals arising purely from noise. Nonetheless, the overall root mean square error is reduced in most regions and parameters. Using the adaptive 4D image reconstruction improved model fits can be obtained in poorly modelled regions, leading to reduced errors potentially propagating

  12. Advanced image reconstruction strategies for 4D prostate DCE-MRI: steps toward clinical practicality

    NASA Astrophysics Data System (ADS)

    Stinson, Eric G.; Borisch, Eric A.; Froemming, Adam T.; Kawashima, Akira; Young, Phillip M.; Warndahl, Brent A.; Grimm, Roger C.; Manduca, Armando; Riederer, Stephen J.; Trzasko, Joshua D.

    2015-09-01

    Dynamic contrast-enhanced (DCE) MRI is an important tool for the detection and characterization of primary and recurring prostate cancer. Advanced reconstruction strategies (e.g., sparse or low-rank regression) provide improved depiction of contrast dynamics and pharmacokinetic parameters; however, the high computation cost of reconstructing 4D (3D+time, 50+ frames) datasets typically inhibits their routine clinical use. Here, a novel alternating direction method-of-multipliers (ADMM) optimization strategy is described that enables these methods to be executed in ∠5 minutes, and thus within the standard clinical workflow. After overviewing the mechanics of this approach, high-performance implementation strategies will be discussed and demonstrated through clinical cases.

  13. Validation of percutaneous puncture trajectory during renal access using 4D ultrasound reconstruction

    NASA Astrophysics Data System (ADS)

    Rodrigues, Pedro L.; Rodrigues, Nuno F.; Fonseca, Jaime C.; Vilaça, João. L.

    2015-03-01

    An accurate percutaneous puncture is essential for disintegration and removal of renal stones. Although this procedure has proven to be safe, some organs surrounding the renal target might be accidentally perforated. This work describes a new intraoperative framework where tracked surgical tools are superimposed within 4D ultrasound imaging for security assessment of the percutaneous puncture trajectory (PPT). A PPT is first generated from the skin puncture site towards an anatomical target, using the information retrieved by electromagnetic motion tracking sensors coupled to surgical tools. Then, 2D ultrasound images acquired with a tracked probe are used to reconstruct a 4D ultrasound around the PPT under GPU processing. Volume hole-filling was performed in different processing time intervals by a tri-linear interpolation method. At spaced time intervals, the volume of the anatomical structures was segmented to ascertain if any vital structure is in between PPT and might compromise the surgical success. To enhance the volume visualization of the reconstructed structures, different render transfer functions were used. Results: Real-time US volume reconstruction and rendering with more than 25 frames/s was only possible when rendering only three orthogonal slice views. When using the whole reconstructed volume one achieved 8-15 frames/s. 3 frames/s were reached when one introduce the segmentation and detection if some structure intersected the PPT. The proposed framework creates a virtual and intuitive platform that can be used to identify and validate a PPT to safely and accurately perform the puncture in percutaneous nephrolithotomy.

  14. [Super-resolution reconstruction of lung 4D-CT images based on fast sub-pixel motion estimation].

    PubMed

    Xiao, Shan; Wang, Tingting; Lü, Qingwen; Zhang, Yu

    2015-07-01

    Super-resolution image reconstruction techniques play an important role for improving image resolution of lung 4D-CT. We presents a super-resolution approach based on fast sub-pixel motion estimation to reconstruct lung 4D-CT images. A fast sub-pixel motion estimation method was used to estimate the deformation fields between "frames", and then iterative back projection (IBP) algorithm was employed to reconstruct high-resolution images. Experimental results showed that compared with traditional interpolation method and super-resolution reconstruction algorithm based on full search motion estimation, the proposed method produced clearer images with significantly enhanced image structure details and reduced time for computation.

  15. Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction

    PubMed Central

    Kazantsev, Daniil; Guo, Enyu; Kaestner, Anders; Lionheart, William R. B.; Bent, Julian; Withers, Philip J.; Lee, Peter D.

    2016-01-01

    X-ray imaging applications in medical and material sciences are frequently limited by the number of tomographic projections collected. The inversion of the limited projection data is an ill-posed problem and needs regularization. Traditional spatial regularization is not well adapted to the dynamic nature of time-lapse tomography since it discards the redundancy of the temporal information. In this paper, we propose a novel iterative reconstruction algorithm with a nonlocal regularization term to account for time-evolving datasets. The aim of the proposed nonlocal penalty is to collect the maximum relevant information in the spatial and temporal domains. With the proposed sparsity seeking approach in the temporal space, the computational complexity of the classical nonlocal regularizer is substantially reduced (at least by one order of magnitude). The presented reconstruction method can be directly applied to various big data 4D (x, y, z+time) tomographic experiments in many fields. We apply the proposed technique to modelled data and to real dynamic X-ray microtomography (XMT) data of high resolution. Compared to the classical spatio-temporal nonlocal regularization approach, the proposed method delivers reconstructed images of improved resolution and higher contrast while remaining significantly less computationally demanding. PMID:27002902

  16. Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction.

    PubMed

    Kazantsev, Daniil; Guo, Enyu; Kaestner, Anders; Lionheart, William R B; Bent, Julian; Withers, Philip J; Lee, Peter D

    2016-01-01

    X-ray imaging applications in medical and material sciences are frequently limited by the number of tomographic projections collected. The inversion of the limited projection data is an ill-posed problem and needs regularization. Traditional spatial regularization is not well adapted to the dynamic nature of time-lapse tomography since it discards the redundancy of the temporal information. In this paper, we propose a novel iterative reconstruction algorithm with a nonlocal regularization term to account for time-evolving datasets. The aim of the proposed nonlocal penalty is to collect the maximum relevant information in the spatial and temporal domains. With the proposed sparsity seeking approach in the temporal space, the computational complexity of the classical nonlocal regularizer is substantially reduced (at least by one order of magnitude). The presented reconstruction method can be directly applied to various big data 4D (x, y, z+time) tomographic experiments in many fields. We apply the proposed technique to modelled data and to real dynamic X-ray microtomography (XMT) data of high resolution. Compared to the classical spatio-temporal nonlocal regularization approach, the proposed method delivers reconstructed images of improved resolution and higher contrast while remaining significantly less computationally demanding.

  17. Temporal sparsity exploiting nonlocal regularization for 4D computed tomography reconstruction.

    PubMed

    Kazantsev, Daniil; Guo, Enyu; Kaestner, Anders; Lionheart, William R B; Bent, Julian; Withers, Philip J; Lee, Peter D

    2016-01-01

    X-ray imaging applications in medical and material sciences are frequently limited by the number of tomographic projections collected. The inversion of the limited projection data is an ill-posed problem and needs regularization. Traditional spatial regularization is not well adapted to the dynamic nature of time-lapse tomography since it discards the redundancy of the temporal information. In this paper, we propose a novel iterative reconstruction algorithm with a nonlocal regularization term to account for time-evolving datasets. The aim of the proposed nonlocal penalty is to collect the maximum relevant information in the spatial and temporal domains. With the proposed sparsity seeking approach in the temporal space, the computational complexity of the classical nonlocal regularizer is substantially reduced (at least by one order of magnitude). The presented reconstruction method can be directly applied to various big data 4D (x, y, z+time) tomographic experiments in many fields. We apply the proposed technique to modelled data and to real dynamic X-ray microtomography (XMT) data of high resolution. Compared to the classical spatio-temporal nonlocal regularization approach, the proposed method delivers reconstructed images of improved resolution and higher contrast while remaining significantly less computationally demanding. PMID:27002902

  18. Reconstruction of a 4D Particle Distribution Using UnderdeterminedPhase-Space Data

    SciTech Connect

    Rostamizadeh, Afshin

    2005-08-10

    A well defined 4D distribution that describes the transverse spatial coordinates (x,y) and momenta (x',y') of the particles that make up an intense ion beam is of great value to theorists in the field of particle beam physics. If such a distribution truthfully captures the characteristic of the actual beam, it can be used to initialize an extensive simulation, and can yield insight into the processes that affect beam quality. Creating a proper representative distribution of particles is a challenge because the problem is, in general, quite underdetermined. Data is collected through a pair of ''optical slit'' diagnostics which provide two 3D distributions, f(x,y,x') and f(x,y,y'); the challenge is to coalesce these into a full 4D distribution f(x,y,x',y'). Further difficulties are introduced because the data is collected at different longitudinal planes and must be ''remapped'' to a common plane, taking into account the convergence or divergence of the beam as well as any off-centering. This challenge was met by developing a suitable algorithm and implementing it as a ''plug-in'' for the popular scientific image analysis program ImageJ, written entirely in the Java programming language. The algorithm accomplishes the desired remapping and synthesizes a 4D particle distribution, using Monte-Carlo techniques. Preliminary results show that this reconstructed distribution is consistent with actual data that was gathered from the same experiment using a different diagnostic. Also, ''forward'' particle-in-cell (PIC) simulations, that use the reconstructed distribution, match actual data gathered downstream in the experiment. Both these results give us some indication that the reconstruction is being done correctly. In addition to the multi-particle synthesis, the plug-in allows for the easy loading of digital data and the output of various plots that are useful to both experimenters and theorists. It also provides a framework by which its applicability can be extended to

  19. SU-D-207-04: GPU-Based 4D Cone-Beam CT Reconstruction Using Adaptive Meshing Method

    SciTech Connect

    Zhong, Z; Gu, X; Iyengar, P; Mao, W; Wang, J; Guo, X

    2015-06-15

    Purpose: Due to the limited number of projections at each phase, the image quality of a four-dimensional cone-beam CT (4D-CBCT) is often degraded, which decreases the accuracy of subsequent motion modeling. One of the promising methods is the simultaneous motion estimation and image reconstruction (SMEIR) approach. The objective of this work is to enhance the computational speed of the SMEIR algorithm using adaptive feature-based tetrahedral meshing and GPU-based parallelization. Methods: The first step is to generate the tetrahedral mesh based on the features of a reference phase 4D-CBCT, so that the deformation can be well captured and accurately diffused from the mesh vertices to voxels of the image volume. After the mesh generation, the updated motion model and other phases of 4D-CBCT can be obtained by matching the 4D-CBCT projection images at each phase with the corresponding forward projections of the deformed reference phase of 4D-CBCT. The entire process of this 4D-CBCT reconstruction method is implemented on GPU, resulting in significantly increasing the computational efficiency due to its tremendous parallel computing ability. Results: A 4D XCAT digital phantom was used to test the proposed mesh-based image reconstruction algorithm. The image Result shows both bone structures and inside of the lung are well-preserved and the tumor position can be well captured. Compared to the previous voxel-based CPU implementation of SMEIR, the proposed method is about 157 times faster for reconstructing a 10 -phase 4D-CBCT with dimension 256×256×150. Conclusion: The GPU-based parallel 4D CBCT reconstruction method uses the feature-based mesh for estimating motion model and demonstrates equivalent image Result with previous voxel-based SMEIR approach, with significantly improved computational speed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  1. Reconstruction of 4D-CT data sets acquired during free breathing for the analysis of respiratory motion

    NASA Astrophysics Data System (ADS)

    Ehrhardt, Jan; Werner, Rene; Frenzel, Thorsten; Säring, Dennis; Lu, Wei; Low, Daniel; Handels, Heinz

    2006-03-01

    Respiratory motion is a significant source of error in radiotherapy treatment planning. 4D-CT data sets can be useful to measure the impact of organ motion caused by breathing. But modern CT scanners can only scan a limited region of the body simultaneously and patients have to be scanned in segments consisting of multiple slices. For studying free breathing motion multislice CT scans can be collected simultaneously with digital spirometry over several breathing cycles. The 4D data set is assembled by sorting the free breathing multislice CT scans according to the couch position and the tidal volume. But artifacts can occur because there are no data segments for exactly the same tidal volume and all couch positions. We present an optical flow based method for the reconstruction of 4D-CT data sets from multislice CT scans, which are collected simultaneously with digital spirometry. The optical flow between the scans is estimated by a non-linear registration method. The calculated velocity field is used to reconstruct a 4D-CT data set by interpolating data at user-defined tidal volumes. By this technique, artifacts can be reduced significantly. The reconstructed 4D-CT data sets are used for studying inner organ motion during the respiratory cycle. The procedures described were applied to reconstruct 4D-CT data sets for four tumour patients who have been scanned during free breathing. The reconstructed 4D data sets were used to quantify organ displacements and to visualize the abdominothoracic organ motion.

  2. Automated 4D lung computed tomography reconstruction during free breathing for conformal radiation therapy

    NASA Astrophysics Data System (ADS)

    El Naqa, Issam M.; Low, Daniel A.; Christensen, Gary E.; Parikh, Parag J.; Song, Joo Hyun; Nystrom, Michelle M.; Lu, Wei; Deasy, Joseph O.; Hubenschmidt, James P.; Wahab, Sasha H.; Mutic, Sasa; Singh, Anurag K.; Bradley, Jeffrey D.

    2004-04-01

    We are developing 4D-CT to provide breathing motion information (trajectories) for radiation therapy treatment planning of lung cancer. Potential applications include optimization of intensity-modulated beams in the presence of breathing motion and intra-fraction target volume margin determination for conformal therapy. The images are acquired using a multi-slice CT scanner while the patient undergoes simultaneous quantitative spirometry. At each couch position, the CT scanner is operated in ciné mode and acquires up to 15 scans of 12 slices each. Each CT scan is associated with the measured tidal volume for retrospective reconstruction of 3D CT scans at arbitrary tidal volumes. The specific tasks of this project involves the development of automated registration of internal organ motion (trajectories) during breathing. A modified least-squares based optical flow algorithm tracks specific features of interest by modifying the eigenvalues of gradient matrix (gradient structural tensor). Good correlations between the measured motion and spirometry-based tidal volume are observed and evidence of internal hysteresis is also detected.

  3. 5D respiratory motion model based image reconstruction algorithm for 4D cone-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Liu, Jiulong; Zhang, Xue; Zhang, Xiaoqun; Zhao, Hongkai; Gao, Yu; Thomas, David; Low, Daniel A.; Gao, Hao

    2015-11-01

    4D cone-beam computed tomography (4DCBCT) reconstructs a temporal sequence of CBCT images for the purpose of motion management or 4D treatment in radiotherapy. However the image reconstruction often involves the binning of projection data to each temporal phase, and therefore suffers from deteriorated image quality due to inaccurate or uneven binning in phase, e.g., under the non-periodic breathing. A 5D model has been developed as an accurate model of (periodic and non-periodic) respiratory motion. That is, given the measurements of breathing amplitude and its time derivative, the 5D model parametrizes the respiratory motion by three time-independent variables, i.e., one reference image and two vector fields. In this work we aim to develop a new 4DCBCT reconstruction method based on 5D model. Instead of reconstructing a temporal sequence of images after the projection binning, the new method reconstructs time-independent reference image and vector fields with no requirement of binning. The image reconstruction is formulated as a optimization problem with total-variation regularization on both reference image and vector fields, and the problem is solved by the proximal alternating minimization algorithm, during which the split Bregman method is used to reconstruct the reference image, and the Chambolle's duality-based algorithm is used to reconstruct the vector fields. The convergence analysis of the proposed algorithm is provided for this nonconvex problem. Validated by the simulation studies, the new method has significantly improved image reconstruction accuracy due to no binning and reduced number of unknowns via the use of the 5D model.

  4. Adaptive patch-based POCS approach for super resolution reconstruction of 4D-CT lung data.

    PubMed

    Wang, Tingting; Cao, Lei; Yang, Wei; Feng, Qianjin; Chen, Wufan; Zhang, Yu

    2015-08-01

    Image enhancement of lung four-dimensional computed tomography (4D-CT) data is highly important because image resolution remains a crucial point in lung cancer radiotherapy. In this paper, we proposed a method for lung 4D-CT super resolution (SR) by using an adaptive-patch-based projection onto convex sets (POCS) approach, which is in contrast with the global POCS SR algorithm, to recover fine details with lesser artifacts in images. The main contribution of this patch-based approach is that the interfering local structure from other phases can be rejected by employing a similar patch adaptive selection strategy. The effectiveness of our approach is demonstrated through experiments on simulated images and real lung 4D-CT datasets. A comparison with previously published SR reconstruction methods highlights the favorable characteristics of the proposed method.

  5. Adaptive patch-based POCS approach for super resolution reconstruction of 4D-CT lung data

    NASA Astrophysics Data System (ADS)

    Wang, Tingting; Cao, Lei; Yang, Wei; Feng, Qianjin; Chen, Wufan; Zhang, Yu

    2015-08-01

    Image enhancement of lung four-dimensional computed tomography (4D-CT) data is highly important because image resolution remains a crucial point in lung cancer radiotherapy. In this paper, we proposed a method for lung 4D-CT super resolution (SR) by using an adaptive-patch-based projection onto convex sets (POCS) approach, which is in contrast with the global POCS SR algorithm, to recover fine details with lesser artifacts in images. The main contribution of this patch-based approach is that the interfering local structure from other phases can be rejected by employing a similar patch adaptive selection strategy. The effectiveness of our approach is demonstrated through experiments on simulated images and real lung 4D-CT datasets. A comparison with previously published SR reconstruction methods highlights the favorable characteristics of the proposed method.

  6. Super-resolution reconstruction for 4D computed tomography of the lung via the projections onto convex sets approach

    SciTech Connect

    Zhang, Yu E-mail: qianjinfeng08@gmail.com; Wu, Xiuxiu; Yang, Wei; Feng, Qianjin E-mail: qianjinfeng08@gmail.com; Chen, Wufan

    2014-11-01

    Purpose: The use of 4D computed tomography (4D-CT) of the lung is important in lung cancer radiotherapy for tumor localization and treatment planning. Sometimes, dense sampling is not acquired along the superior–inferior direction. This disadvantage results in an interslice thickness that is much greater than in-plane voxel resolutions. Isotropic resolution is necessary for multiplanar display, but the commonly used interpolation operation blurs images. This paper presents a super-resolution (SR) reconstruction method to enhance 4D-CT resolution. Methods: The authors assume that the low-resolution images of different phases at the same position can be regarded as input “frames” to reconstruct high-resolution images. The SR technique is used to recover high-resolution images. Specifically, the Demons deformable registration algorithm is used to estimate the motion field between different “frames.” Then, the projection onto convex sets approach is implemented to reconstruct high-resolution lung images. Results: The performance of the SR algorithm is evaluated using both simulated and real datasets. Their method can generate clearer lung images and enhance image structure compared with cubic spline interpolation and back projection (BP) method. Quantitative analysis shows that the proposed algorithm decreases the root mean square error by 40.8% relative to cubic spline interpolation and 10.2% versus BP. Conclusions: A new algorithm has been developed to improve the resolution of 4D-CT. The algorithm outperforms the cubic spline interpolation and BP approaches by producing images with markedly improved structural clarity and greatly reduced artifacts.

  7. Learning distance function for regression-based 4D pulmonary trunk model reconstruction estimated from sparse MRI data

    NASA Astrophysics Data System (ADS)

    Vitanovski, Dime; Tsymbal, Alexey; Ionasec, Razvan; Georgescu, Bogdan; Zhou, Shaohua K.; Hornegger, Joachim; Comaniciu, Dorin

    2011-03-01

    Congenital heart defect (CHD) is the most common birth defect and a frequent cause of death for children. Tetralogy of Fallot (ToF) is the most often occurring CHD which affects in particular the pulmonary valve and trunk. Emerging interventional methods enable percutaneous pulmonary valve implantation, which constitute an alternative to open heart surgery. While minimal invasive methods become common practice, imaging and non-invasive assessment tools become crucial components in the clinical setting. Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (cMRI) are techniques with complementary properties and ability to acquire multiple non-invasive and accurate scans required for advance evaluation and therapy planning. In contrary to CT which covers the full 4D information over the cardiac cycle, cMRI often acquires partial information, for example only one 3D scan of the whole heart in the end-diastolic phase and two 2D planes (long and short axes) over the whole cardiac cycle. The data acquired in this way is called sparse cMRI. In this paper, we propose a regression-based approach for the reconstruction of the full 4D pulmonary trunk model from sparse MRI. The reconstruction approach is based on learning a distance function between the sparse MRI which needs to be completed and the 4D CT data with the full information used as the training set. The distance is based on the intrinsic Random Forest similarity which is learnt for the corresponding regression problem of predicting coordinates of unseen mesh points. Extensive experiments performed on 80 cardiac CT and MR sequences demonstrated the average speed of 10 seconds and accuracy of 0.1053mm mean absolute error for the proposed approach. Using the case retrieval workflow and local nearest neighbour regression with the learnt distance function appears to be competitive with respect to "black box" regression with immediate prediction of coordinates, while providing transparency to the

  8. Online 4d Reconstruction Using Multi-Images Available Under Open Access

    NASA Astrophysics Data System (ADS)

    Ioannides, M.; Hadjiprocopi, A.; Doulamis, N.; Doulamis, A.; Protopapadakis, E.; Makantasis, K.; Santos, P.; Fellner, D.; Stork, A.; Balet, O.; Julien, M.; Weinlinger, G.; Johnson, P. S.; Klein, M.; Fritsch, D.

    2013-07-01

    The advent of technology in digital cameras and their incorporation into virtually any smart mobile device has led to an explosion of the number of photographs taken every day. Today, the number of images stored online and available freely has reached unprecedented levels. It is estimated that in 2011, there were over 100 billion photographs stored in just one of the major social media sites. This number is growing exponentially. Moreover, advances in the fields of Photogrammetry and Computer Vision have led to significant breakthroughs such as the Structure from Motion algorithm which creates 3D models of objects using their twodimensional photographs. The existence of powerful and affordable computational machinery not only the reconstruction of complex structures but also entire cities. This paper illustrates an overview of our methodology for producing 3D models of Cultural Heritage structures such as monuments and artefacts from 2D data (pictures, video), available on Internet repositories, social media, Google Maps, Bing, etc. We also present new approaches to semantic enrichment of the end results and their subsequent export to Europeana, the European digital library, for integrated, interactive 3D visualisation within regular web browsers using WebGl and X3D. Our main goal is to enable historians, architects, archaeologists, urban planners and affiliated professionals to reconstruct views of historical structures from millions of images floating around the web and interact with them.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. Imaging plant growth in 4D: robust tissue reconstruction and lineaging at cell resolution.

    PubMed

    Fernandez, Romain; Das, Pradeep; Mirabet, Vincent; Moscardi, Eric; Traas, Jan; Verdeil, Jean-Luc; Malandain, Grégoire; Godin, Christophe

    2010-07-01

    Quantitative information on growing organs is required to better understand morphogenesis in both plants and animals. However, detailed analyses of growth patterns at cellular resolution have remained elusive. We developed an approach, multiangle image acquisition, three-dimensional reconstruction and cell segmentation-automated lineage tracking (MARS-ALT), in which we imaged whole organs from multiple angles, computationally merged and segmented these images to provide accurate cell identification in three dimensions and automatically tracked cell lineages through multiple rounds of cell division during development. Using these methods, we quantitatively analyzed Arabidopsis thaliana flower development at cell resolution, which revealed differential growth patterns of key regions during early stages of floral morphogenesis. Lastly, using rice roots, we demonstrated that this approach is both generic and scalable.

  11. Reconstruction of landslide movements by inversion of 4-D electrical resistivity tomography monitoring data

    NASA Astrophysics Data System (ADS)

    Wilkinson, Paul; Chambers, Jonathan; Uhlemann, Sebastian; Meldrum, Philip; Smith, Alister; Dixon, Neil; Loke, Meng Heng

    2016-02-01

    Reliable tomographic inversion of geoelectrical monitoring data from unstable slopes relies critically on knowing the electrode positions, which may move over time. We develop and present an innovative inverse method to recover movements in both surface directions from geoelectrical measurements made on a grid of monitoring electrodes. For the first time, we demonstrate this method using field data from an active landslide to recover sequences of movement over timescales of days to years. Comparison with GPS measurements demonstrated an accuracy of within 10% of the electrode spacing, sufficient to correct the majority of artifacts that would occur in subsequent image reconstructions if incorrect positions are used. Over short timescales where the corresponding subsurface resistivity changes were smaller, the constraints could be relaxed and an order-of-magnitude better accuracy was achievable. This enabled the onset and acceleration of landslide activity to be detected with a temporal resolution of a few days.

  12. Imaging plant growth in 4D: robust tissue reconstruction and lineaging at cell resolution.

    PubMed

    Fernandez, Romain; Das, Pradeep; Mirabet, Vincent; Moscardi, Eric; Traas, Jan; Verdeil, Jean-Luc; Malandain, Grégoire; Godin, Christophe

    2010-07-01

    Quantitative information on growing organs is required to better understand morphogenesis in both plants and animals. However, detailed analyses of growth patterns at cellular resolution have remained elusive. We developed an approach, multiangle image acquisition, three-dimensional reconstruction and cell segmentation-automated lineage tracking (MARS-ALT), in which we imaged whole organs from multiple angles, computationally merged and segmented these images to provide accurate cell identification in three dimensions and automatically tracked cell lineages through multiple rounds of cell division during development. Using these methods, we quantitatively analyzed Arabidopsis thaliana flower development at cell resolution, which revealed differential growth patterns of key regions during early stages of floral morphogenesis. Lastly, using rice roots, we demonstrated that this approach is both generic and scalable. PMID:20543845

  13. 4D reconstruction of the past: the image retrieval and 3D model construction pipeline

    NASA Astrophysics Data System (ADS)

    Hadjiprocopis, Andreas; Ioannides, Marinos; Wenzel, Konrad; Rothermel, Mathias; Johnsons, Paul S.; Fritsch, Dieter; Doulamis, Anastasios; Protopapadakis, Eftychios; Kyriakaki, Georgia; Makantasis, Kostas; Weinlinger, Guenther; Klein, Michael; Fellner, Dieter; Stork, Andre; Santos, Pedro

    2014-08-01

    One of the main characteristics of the Internet era we are living in, is the free and online availability of a huge amount of data. This data is of varied reliability and accuracy and exists in various forms and formats. Often, it is cross-referenced and linked to other data, forming a nexus of text, images, animation and audio enabled by hypertext and, recently, by the Web3.0 standard. Our main goal is to enable historians, architects, archaeolo- gists, urban planners and affiliated professionals to reconstruct views of historical monuments from thousands of images floating around the web. This paper aims to provide an update of our progress in designing and imple- menting a pipeline for searching, filtering and retrieving photographs from Open Access Image Repositories and social media sites and using these images to build accurate 3D models of archaeological monuments as well as enriching multimedia of cultural / archaeological interest with metadata and harvesting the end products to EU- ROPEANA. We provide details of how our implemented software searches and retrieves images of archaeological sites from Flickr and Picasa repositories as well as strategies on how to filter the results, on two levels; a) based on their built-in metadata including geo-location information and b) based on image processing and clustering techniques. We also describe our implementation of a Structure from Motion pipeline designed for producing 3D models using the large collection of 2D input images (>1000) retrieved from Internet Repositories.

  14. Three-channel dynamic photometric stereo: a new method for 4D surface reconstruction and volume recovery

    NASA Astrophysics Data System (ADS)

    Schroeder, Walter; Schulze, Wolfram; Wetter, Thomas; Chen, Chi-Hsien

    2008-08-01

    Three-dimensional (3D) body surface reconstruction is an important field in health care. A popular method for this purpose is laser scanning. However, using Photometric Stereo (PS) to record lumbar lordosis and the surface contour of the back poses a viable alternative due to its lower costs and higher flexibility compared to laser techniques and other methods of three-dimensional body surface reconstruction. In this work, we extended the traditional PS method and proposed a new method for obtaining surface and volume data of a moving object. The principle of traditional Photometric Stereo uses at least three images of a static object taken under different light sources to obtain 3D information of the object. Instead of using normal light, the light sources in the proposed method consist of the RGB-Color-Model's three colors: red, green and blue. A series of pictures taken with a video camera can now be separated into the different color channels. Each set of the three images can then be used to calculate the surface normals as a traditional PS. This method waives the requirement that the object imaged must be kept still as in almost all the other body surface reconstruction methods. By putting two cameras opposite to a moving object and lighting the object with the colored light, the time-varying surface (4D) data can easily be calculated. The obtained information can be used in many medical fields such as rehabilitation, diabetes screening or orthopedics.

  15. Dosimetric quality assurance of highly conformal external beam treatments: from 2D phantom comparisons to 4D patient dose reconstruction

    NASA Astrophysics Data System (ADS)

    Feygelman, V.; Nelms, B.

    2013-06-01

    As IMRT technology continues to evolve, so do the dosimetric QA methods. A historical review of those is presented, starting with longstanding techniques such as film and ion chamber in a phantom and progressing towards 3D and 4D dose reconstruction in the patient. Regarding patient-specific QA, we envision that the currently prevalent limited comparison of dose distributions in the phantom by γ-analysis will be eventually replaced by clinically meaningful patient dose analyses with improved sensitivity and specificity. In a larger sense, we envision a future of QA built upon lessons from the rich history of "quality" as a science and philosophy. This future will aim to improve quality (and ultimately reduce cost) via advanced commissioning processes that succeed in detecting and rooting out systematic errors upstream of patient treatment, thus reducing our reliance on, and the resource burden associated with, per-beam/per-plan inspection.

  16. SU-E-J-153: Reconstructing 4D Cone Beam CT Images for Clinical QA of Lung SABR Treatments

    SciTech Connect

    Beaudry, J; Bergman, A; Cropp, R

    2015-06-15

    Purpose: To verify that the planned Primary Target Volume (PTV) and Internal Gross Tumor Volume (IGTV) fully enclose a moving lung tumor volume as visualized on a pre-SABR treatment verification 4D Cone Beam CT. Methods: Daily 3DCBCT image sets were acquired immediately prior to treatment for 10 SABR lung patients using the on-board imaging system integrated into a Varian TrueBeam (v1.6: no 4DCBCT module available). Respiratory information was acquired during the scan using the Varian RPM system. The CBCT projections were sorted into 8 bins offline, both by breathing phase and amplitude, using in-house software. An iterative algorithm based on total variation minimization, implemented in the open source reconstruction toolkit (RTK), was used to reconstruct the binned projections into 4DCBCT images. The relative tumor motion was quantified by tracking the centroid of the tumor volume from each 4DCBCT image. Following CT-CBCT registration, the planning CT volumes were compared to the location of the CBCT tumor volume as it moves along its breathing trajectory. An overlap metric quantified the ability of the planned PTV and IGTV to contain the tumor volume at treatment. Results: The 4DCBCT reconstructed images visibly show the tumor motion. The mean overlap between the planned PTV (IGTV) and the 4DCBCT tumor volumes was 100% (94%), with an uncertainty of 5% from the 4DCBCT tumor volume contours. Examination of the tumor motion and overlap metric verify that the IGTV drawn at the planning stage is a good representation of the tumor location at treatment. Conclusion: It is difficult to compare GTV volumes from a 4DCBCT and a planning CT due to image quality differences. However, it was possible to conclude the GTV remained within the PTV 100% of the time thus giving the treatment staff confidence that SABR lung treatements are being delivered accurately.

  17. SU-E-J-02: 4D Digital Tomosynthesis Based On Algebraic Image Reconstruction and Total-Variation Minimization for the Improvement of Image Quality

    SciTech Connect

    Kim, D; Kang, S; Kim, T; Suh, T; Kim, S

    2014-06-01

    Purpose: In this paper, we implemented the four-dimensional (4D) digital tomosynthesis (DTS) imaging based on algebraic image reconstruction technique and total-variation minimization method in order to compensate the undersampled projection data and improve the image quality. Methods: The projection data were acquired as supposed the cone-beam computed tomography system in linear accelerator by the Monte Carlo simulation and the in-house 4D digital phantom generation program. We performed 4D DTS based upon simultaneous algebraic reconstruction technique (SART) among the iterative image reconstruction technique and total-variation minimization method (TVMM). To verify the effectiveness of this reconstruction algorithm, we performed systematic simulation studies to investigate the imaging performance. Results: The 4D DTS algorithm based upon the SART and TVMM seems to give better results than that based upon the existing method, or filtered-backprojection. Conclusion: The advanced image reconstruction algorithm for the 4D DTS would be useful to validate each intra-fraction motion during radiation therapy. In addition, it will be possible to give advantage to real-time imaging for the adaptive radiation therapy. This research was supported by Leading Foreign Research Institute Recruitment Program (Grant No.2009-00420) and Basic Atomic Energy Research Institute (BAERI); (Grant No. 2009-0078390) through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT and Future Planning (MSIP)

  18. Determination of optimal collimation parameters for a rotating slat collimator system: a system matrix method using ML-EM

    NASA Astrophysics Data System (ADS)

    Boisson, F.; Bekaert, V.; Brasse, D.

    2016-03-01

    Nowadays, Single Photon imaging has become an essential part of molecular imaging and nuclear medicine. Whether to establish a diagnosis or in the therapeutic monitoring, this modality presents performance that continues to improve. For over 50 years, several collimators have been proposed. Mainly governed by collimation parameters, the resolution-sensitivity trade-off is the factor determining the collimator the most suitable for an intended study. One alternative to the common approaches is the rotating slat collimator (RSC). In the present study, we are aiming at developing a preclinical system equipped with a RSC dedicated to mice and rats imaging, which requires both high sensitivity and spatial resolution. We investigated the resolution-sensitivity trade-offs obtained by varying different collimation parameters: (i) the slats height (H), and (ii) the gap between two consecutive slats (g), considering different intrinsic spatial resolutions. One system matrix was generated for each set of collimation parameters (H,g). Spatial resolutions, Signal-to-Noise Ratio (SNR) and sensitivity obtained for all the set of collimation parameters (H,g) were measured in the 2D projections reconstructed with ML-EM. According to our results, 20 mm high slats and a 1 mm gap were chosen as a good RSC candidate for a preclinical detection module. This collimator will ensure a sensitivity greater than 0.2% and a system spatial resolution below 1 mm, considering an intrinsic spatial resolution below 0.8 mm.

  19. Determination of optimal collimation parameters for a rotating slat collimator system: a system matrix method using ML-EM.

    PubMed

    Boisson, F; Bekaert, V; Brasse, D

    2016-03-21

    Nowadays, Single Photon imaging has become an essential part of molecular imaging and nuclear medicine. Whether to establish a diagnosis or in the therapeutic monitoring, this modality presents performance that continues to improve. For over 50 years, several collimators have been proposed. Mainly governed by collimation parameters, the resolution-sensitivity trade-off is the factor determining the collimator the most suitable for an intended study. One alternative to the common approaches is the rotating slat collimator (RSC). In the present study, we are aiming at developing a preclinical system equipped with a RSC dedicated to mice and rats imaging, which requires both high sensitivity and spatial resolution. We investigated the resolution-sensitivity trade-offs obtained by varying different collimation parameters: (i) the slats height (H), and (ii) the gap between two consecutive slats (g), considering different intrinsic spatial resolutions. One system matrix was generated for each set of collimation parameters (H,g). Spatial resolutions, Signal-to-Noise Ratio (SNR) and sensitivity obtained for all the set of collimation parameters (H,g) were measured in the 2D projections reconstructed with ML-EM. According to our results, 20 mm high slats and a 1 mm gap were chosen as a good RSC candidate for a preclinical detection module. This collimator will ensure a sensitivity greater than 0.2% and a system spatial resolution below 1 mm, considering an intrinsic spatial resolution below 0.8 mm. PMID:26930449

  20. SU-E-J-246: A Deformation-Field Map Based Liver 4D CBCT Reconstruction Method Using Gold Nanoparticles as Constraints

    SciTech Connect

    Harris, W; Zhang, Y; Ren, L; Yin, F

    2014-06-01

    Purpose: To investigate the feasibility of using nanoparticle markers to validate liver tumor motion together with a deformation field map-based four dimensional (4D) cone-beam computed tomography (CBCT) reconstruction method. Methods: A technique for lung 4D-CBCT reconstruction has been previously developed using a deformation field map (DFM)-based strategy. In this method, each phase of the 4D-CBCT is considered as a deformation of a prior CT volume. The DFM is solved by a motion modeling and free-form deformation (MM-FD) technique, using a data fidelity constraint and the deformation energy minimization. For liver imaging, there is low contrast of a liver tumor in on-board projections. A validation of liver tumor motion using implanted gold nanoparticles, along with the MM-FD deformation technique is implemented to reconstruct onboard 4D CBCT liver radiotherapy images. These nanoparticles were placed around the liver tumor to reflect the tumor positions in both CT simulation and on-board image acquisition. When reconstructing each phase of the 4D-CBCT, the migrations of the gold nanoparticles act as a constraint to regularize the deformation field, along with the data fidelity and the energy minimization constraints. In this study, multiple tumor diameters and positions were simulated within the liver for on-board 4D-CBCT imaging. The on-board 4D-CBCT reconstructed by the proposed method was compared with the “ground truth” image. Results: The preliminary data, which uses reconstruction for lung radiotherapy suggests that the advanced reconstruction algorithm including the gold nanoparticle constraint will Resultin volume percentage differences (VPD) between lesions in reconstructed images by MM-FD and “ground truth” on-board images of 11.5% (± 9.4%) and a center of mass shift of 1.3 mm (± 1.3 mm) for liver radiotherapy. Conclusion: The advanced MM-FD technique enforcing the additional constraints from gold nanoparticles, results in improved accuracy

  1. SU-D-17A-01: Geometric and Dosimetric Evaluation of a 4D-CBCT Reconstruction Technique Using Prior Knowledge

    SciTech Connect

    Zhang, Y; Yin, F; Ren, L

    2014-06-01

    Purpose: To evaluate a 4D-CBCT reconstruction technique both geometrically and dosimetrically Methods: A prior-knowledge guided 4DC-BCT reconstruction method named the motion-modeling and free-form deformation (MM-FD) has been developed. MM-FD views each phase of the 4D-CBCT as a deformation of a prior CT volume. The deformation field is first solved by principal component analysis based motion modeling, followed by constrained free-form deformation.The 4D digital extended-cardiac- torso (XCAT) phantom was used for comprehensive evaluation. Based on a simulated 4D planning CT of a lung patient, 8 different scenarios were simulated to cover the typical on-board anatomical and respiratory variations: (1) synchronized and (2) unsynchronized motion amplitude change for body and tumor; tumor (3) shrinkage and (4) expansion; tumor average position shift in (5) superior-inferior (SI) direction, (6) anterior-posterior (AP) direction and (7) SI, AP and lateral directions altogether; and (8) tumor phase shift relative to the respiratory cycle of the body. Orthogonal-view 30° projections were simulated based on the eight patient scenarios to reconstruct on-board 4D-CBCTs. For geometric evaluation, the volume-percentage-difference (VPD) was calculated to assess the volumetric differences between the reconstructed and the ground-truth tumor.For dosimetric evaluation, a gated treatment plan was designed for the prior 4D-CT. The dose distributions were calculated on the reconstructed 4D-CBCTs and the ground-truth images for comparison. The MM-FD technique was compared with MM-only and FD-only techniques. Results: The average (±s.d.) VPD values of reconstructed tumors for MM-only, FDonly and MM-FD methods were 59.16%(± 26.66%), 75.98%(± 27.21%) and 5.22%(± 2.12%), respectively. The average min/max/mean dose (normalized to prescription) of the reconstructed tumors by MM-only, FD-only, MM-FD methods and ground-truth tumors were 78.0%/122.2%/108.2%, 13%/117.7%/86%, 58

  2. Metal-ceramic interfaces: Overlayer-induced reconstruction and magnetism of 4d transition-metal monolayers

    SciTech Connect

    Wu, R.; Freeman, A.J.

    1995-02-15

    Structural, electronic, and magnetic properties of metal-ceramic interfaces, M/MgO(001) (M=Pd, Rh, and Ru), have been investigated using the full potential linearized augmented-plane-wave method. Ru and Rh monolayers are found to be able to retain large spin magnetic moments on MgO(001) (1.95 {mu}{sub B} and 1.21 {mu}{sub B} for Ru and Ph; respectively) -- indicating, in principle, the potential application of MgO(001) as a benign substrate for 4d monolayer magnetism. Significantly, according to our atomic-force determinations, the metal overlayers induce a sizable buckling reconstruction in the interfacial MgO layer, which enhances the M-MgO binding energy by 0.1 eV. The weak M-0 interaction is mainly via tail effects; however, it affects the density of states at the Fermi level for Pd/Mg0(001) significantly and completely eliminates the small magnetic moment of the free Pd monolaver (0.34{mu}{sub B}).

  3. Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study

    NASA Astrophysics Data System (ADS)

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M.; Tsui, Benjamin M. W.

    2015-09-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  4. Task-based evaluation of a 4D MAP-RBI-EM image reconstruction method for gated myocardial perfusion SPECT using a human observer study.

    PubMed

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M; Tsui, Benjamin M W

    2015-09-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  5. Task-Based Evaluation of a 4D MAP-RBI-EM Image Reconstruction Method for Gated Myocardial Perfusion SPECT using a Human Observer Study

    PubMed Central

    Lee, Taek-Soo; Higuchi, Takahiro; Lautamäki, Riikka; Bengel, Frank M.; Tsui, Benjamin M. W.

    2015-01-01

    We evaluated the performance of a new 4D image reconstruction method for improved 4D gated myocardial perfusion (MP) SPECT using a task-based human observer study. We used a realistic 4D NURBS-based Cardiac-Torso (NCAT) phantom that models cardiac beating motion. Half of the population was normal; the other half had a regional hypokinetic wall motion abnormality. Noise-free and noisy projection data with 16 gates/cardiac cycle were generated using an analytical projector that included the effects of attenuation, collimator-detector response, and scatter (ADS), and were reconstructed using the 3D FBP without and 3D OS-EM with ADS corrections followed by different cut-off frequencies of a 4D linear post-filter. A 4D iterative maximum a posteriori rescaled-block (MAP-RBI)-EM image reconstruction method with ADS corrections was also used to reconstruct the projection data using various values of the weighting factor for its prior. The trade-offs between bias and noise were represented by the normalized mean squared error (NMSE) and averaged normalized standard deviation (NSDav), respectively. They were used to select reasonable ranges of the reconstructed images for use in a human observer study. The observers were trained with the simulated cine images and were instructed to rate their confidence on the absence or presence of a motion defect on a continuous scale. We then applied receiver operating characteristic (ROC) analysis and used the area under the ROC curve (AUC) index. The results showed that significant differences in detection performance among the different NMSE-NSDav combinations were found and the optimal trade-off from optimized reconstruction parameters corresponded to a maximum AUC value. The 4D MAP-RBI-EM with ADS correction, which had the best trade-off among the tested reconstruction methods, also had the highest AUC value, resulting in significantly better human observer detection performance when detecting regional myocardial wall motion

  6. Impact of scanning parameters and breathing patterns on image quality and accuracy of tumor motion reconstruction in 4D CBCT: a phantom study.

    PubMed

    Lee, Soyoung; Yan, Guanghua; Lu, Bo; Kahler, Darren; Li, Jonathan G; Sanjiv, Samat S

    2015-01-01

    Four-dimensional, cone-beam CT (4D CBCT) substantially reduces respiration-induced motion blurring artifacts in three-dimension (3D) CBCT. However, the image quality of 4D CBCT is significantly degraded which may affect its accuracy in localizing a mobile tumor for high-precision, image-guided radiation therapy (IGRT). The purpose of this study was to investigate the impact of scanning parameters hereinafter collectively referred to as scanning sequence) and breathing patterns on the image quality and the accuracy of computed tumor trajectory for a commercial 4D CBCT system, in preparation for its clinical implementation. We simulated a series of periodic and aperiodic sinusoidal breathing patterns with a respiratory motion phantom. The aperiodic pattern was created by varying the period or amplitude of individual sinusoidal breathing cycles. 4D CBCT scans of the phantom were acquired with a manufacturer-supplied scanning sequence (4D-S-slow) and two in-house modified scanning sequences (4D-M-slow and 4D-M-fast). While 4D-S-slow used small field of view (FOV), partial rotation (200°), and no imaging filter, 4D-M-slow and 4D-M-fast used medium FOV, full rotation, and the F1 filter. The scanning speed was doubled in 4D-M-fast (100°/min gantry rotation). The image quality of the 4D CBCT scans was evaluated using contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and motion blurring ratio (MBR). The trajectory of the moving target was reconstructed by registering each phase of the 4D CBCT with a reference CT. The root-mean-squared-error (RMSE) analysis was used to quantify its accuracy. Significant decrease in CNR and SNR from 3D CBCT to 4D CBCT was observed. The 4D-S-slow and 4D-M-fast scans had comparable image quality, while the 4D-M-slow scans had better performance due to doubled projections. Both CNR and SNR decreased slightly as the breathing period increased, while no dependence on the amplitude was observed. The difference of both CNR and SNR

  7. Impact of time-of-flight on indirect 3D and direct 4D parametric image reconstruction in the presence of inconsistent dynamic PET data.

    PubMed

    Kotasidis, F A; Mehranian, A; Zaidi, H

    2016-05-01

    Kinetic parameter estimation in dynamic PET suffers from reduced accuracy and precision when parametric maps are estimated using kinetic modelling following image reconstruction of the dynamic data. Direct approaches to parameter estimation attempt to directly estimate the kinetic parameters from the measured dynamic data within a unified framework. Such image reconstruction methods have been shown to generate parametric maps of improved precision and accuracy in dynamic PET. However, due to the interleaving between the tomographic and kinetic modelling steps, any tomographic or kinetic modelling errors in certain regions or frames, tend to spatially or temporally propagate. This results in biased kinetic parameters and thus limits the benefits of such direct methods. Kinetic modelling errors originate from the inability to construct a common single kinetic model for the entire field-of-view, and such errors in erroneously modelled regions could spatially propagate. Adaptive models have been used within 4D image reconstruction to mitigate the problem, though they are complex and difficult to optimize. Tomographic errors in dynamic imaging on the other hand, can originate from involuntary patient motion between dynamic frames, as well as from emission/transmission mismatch. Motion correction schemes can be used, however, if residual errors exist or motion correction is not included in the study protocol, errors in the affected dynamic frames could potentially propagate either temporally, to other frames during the kinetic modelling step or spatially, during the tomographic step. In this work, we demonstrate a new strategy to minimize such error propagation in direct 4D image reconstruction, focusing on the tomographic step rather than the kinetic modelling step, by incorporating time-of-flight (TOF) within a direct 4D reconstruction framework. Using ever improving TOF resolutions (580 ps, 440 ps, 300 ps and 160 ps), we demonstrate that direct 4D TOF image

  8. Impact of time-of-flight on indirect 3D and direct 4D parametric image reconstruction in the presence of inconsistent dynamic PET data

    NASA Astrophysics Data System (ADS)

    Kotasidis, F. A.; Mehranian, A.; Zaidi, H.

    2016-05-01

    Kinetic parameter estimation in dynamic PET suffers from reduced accuracy and precision when parametric maps are estimated using kinetic modelling following image reconstruction of the dynamic data. Direct approaches to parameter estimation attempt to directly estimate the kinetic parameters from the measured dynamic data within a unified framework. Such image reconstruction methods have been shown to generate parametric maps of improved precision and accuracy in dynamic PET. However, due to the interleaving between the tomographic and kinetic modelling steps, any tomographic or kinetic modelling errors in certain regions or frames, tend to spatially or temporally propagate. This results in biased kinetic parameters and thus limits the benefits of such direct methods. Kinetic modelling errors originate from the inability to construct a common single kinetic model for the entire field-of-view, and such errors in erroneously modelled regions could spatially propagate. Adaptive models have been used within 4D image reconstruction to mitigate the problem, though they are complex and difficult to optimize. Tomographic errors in dynamic imaging on the other hand, can originate from involuntary patient motion between dynamic frames, as well as from emission/transmission mismatch. Motion correction schemes can be used, however, if residual errors exist or motion correction is not included in the study protocol, errors in the affected dynamic frames could potentially propagate either temporally, to other frames during the kinetic modelling step or spatially, during the tomographic step. In this work, we demonstrate a new strategy to minimize such error propagation in direct 4D image reconstruction, focusing on the tomographic step rather than the kinetic modelling step, by incorporating time-of-flight (TOF) within a direct 4D reconstruction framework. Using ever improving TOF resolutions (580 ps, 440 ps, 300 ps and 160 ps), we demonstrate that direct 4D TOF image

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

    SciTech Connect

    Shieh, Chun-Chien; Kipritidis, John; O’Brien, Ricky T.; Keall, Paul J.; Kuncic, Zdenka

    2014-04-15

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

  10. SU-D-17A-03: 5D Respiratory Motion Model Based Iterative Reconstruction Method for 4D Cone-Beam CT

    SciTech Connect

    Gao, Y; Thomas, D; Low, D; Gao, H

    2014-06-01

    Purpose: The purpose of this work is to develop a new iterative reconstruction method for 4D cone-beam CT (CBCT) based on a published time-independent 5D respiratory motion model. The proposed method will offer a single high-resolution image at a user-selected breathing phase and the 5D motion model parameters, which could be used to generate the breathing pattern during the CT acquisition. Methods: 5D respiratory motion model was proposed for accurately modeling the motion of lung and lung tumor tissues. 4D images are then parameterized by a reference image, measured breathing amplitude, breathing rate, two time-independent vector fields that describe the 5D model parameters, and a scalar field that describes the change in HU as a function of breathing amplitude. In contrast with the traditional method of reconstructing multiple temporal image phases to reduce respiratory artifact, 5D model based method simplify the problem into the reconstruction of a single reference image and the 5D motion model parameters. The reconstruction formulation of the reference image and scalar and vector fields is a nonlinear least-square optimization problem that consists of solving the reference image and fields alternately, in which the reference image is regularized with the total variation sparsity transform and the vector fields are solved through linearizations regularized by the H1 norm. 2D lung simulations were performed in this proof-of-concept study. Results: The breathing amplitude, its rate, and the corresponding scalar and vector fields were generated from a patient case. Compared with filtered backprojection method and sparsity regularized iterative method for the phase-by-phase reconstruction, the proposed 5D motion model based method yielded improved image quality. Conclusion: Based on 5D respiratory motion model, we have developed a new iterative reconstruction method for 4D CBCT that has the potential for improving image quality while providing needed on

  11. SU-E-J-74: Impact of Respiration-Correlated Image Quality On Tumor Motion Reconstruction in 4D-CBCT: A Phantom Study

    SciTech Connect

    Lee, S; Lu, B; Samant, S

    2014-06-01

    Purpose: To investigate the effects of scanning parameters and respiratory patterns on the image quality for 4-dimensional cone-beam computed tomography(4D-CBCT) imaging, and assess the accuracy of computed tumor trajectory for lung imaging using registration of phased 4D-CBCT imaging with treatment planning-CT. Methods: We simulated a periodic and non-sinusoidal respirations with various breathing periods and amplitudes using a respiratory phantom(Quasar, Modus Medical Devices Inc) to acquire respiration-correlated 4D-CBCT images. 4D-CBCT scans(Elekta Oncology Systems Ltd) were performed with different scanning parameters for collimation size(e.g., small and medium field-of-views) and scanning speed(e.g., slow 50°·min{sup −1}, fast 100°·min{sup −1}). Using a standard CBCT-QA phantom(Catphan500, The Phantom Laboratory), the image qualities of all phases in 4D-CBCT were evaluated with contrast-to-noise ratio(CNR) for lung tissue and uniformity in each module. Using a respiratory phantom, the target imaging in 4D-CBCT was compared to 3D-CBCT target image. The target trajectory from 10-respiratory phases in 4D-CBCT was extracted using an automatic image registration and subsequently assessed the accuracy by comparing with actual motion of the target. Results: Image analysis indicated that a short respiration with a small amplitude resulted in superior CNR and uniformity. Smaller variation of CNR and uniformity was present amongst different respiratory phases. The small field-of-view with a partial scan using slow scan can improve CNR, but degraded uniformity. Large amplitude of respiration can degrade image quality. RMS of voxel densities in tumor area of 4D-CBCT images between sinusoidal and non-sinusoidal motion exhibited no significant difference. The maximum displacement errors of motion trajectories were less than 1.0 mm and 13.5 mm, for sinusoidal and non-sinusoidal breathings, respectively. The accuracy of motion reconstruction showed good overall

  12. Evaluation of the reliability of the maximum entropy method for reconstructing 3D and 4D NOESY-type NMR spectra of proteins.

    PubMed

    Shigemitsu, Yoshiki; Ikeya, Teppei; Yamamoto, Akihiro; Tsuchie, Yuusuke; Mishima, Masaki; Smith, Brian O; Güntert, Peter; Ito, Yutaka

    2015-02-01

    Despite their advantages in analysis, 4D NMR experiments are still infrequently used as a routine tool in protein NMR projects due to the long duration of the measurement and limited digital resolution. Recently, new acquisition techniques for speeding up multidimensional NMR experiments, such as nonlinear sampling, in combination with non-Fourier transform data processing methods have been proposed to be beneficial for 4D NMR experiments. Maximum entropy (MaxEnt) methods have been utilised for reconstructing nonlinearly sampled multi-dimensional NMR data. However, the artefacts arising from MaxEnt processing, particularly, in NOESY spectra have not yet been clearly assessed in comparison with other methods, such as quantitative maximum entropy, multidimensional decomposition, and compressed sensing. We compared MaxEnt with other methods in reconstructing 3D NOESY data acquired with variously reduced sparse sampling schedules and found that MaxEnt is robust, quick and competitive with other methods. Next, nonlinear sampling and MaxEnt processing were applied to 4D NOESY experiments, and the effect of the artefacts of MaxEnt was evaluated by calculating 3D structures from the NOE-derived distance restraints. Our results demonstrated that sufficiently converged and accurate structures (RMSD of 0.91Å to the mean and 1.36Å to the reference structures) were obtained even with NOESY spectra reconstructed from 1.6% randomly selected sampling points for indirect dimensions. This suggests that 3D MaxEnt processing in combination with nonlinear sampling schedules is still a useful and advantageous option for rapid acquisition of high-resolution 4D NOESY spectra of proteins.

  13. Four-dimensional cardiac reconstruction from rotational x-ray sequences: first results for 4D coronary angiography

    NASA Astrophysics Data System (ADS)

    Hansis, Eberhard; Schomberg, Hermann; Erhard, Klaus; Dössel, Olaf; Grass, Michael

    2009-02-01

    The tomographic reconstruction of the beating heart requires dedicated methods. One possibility is gated reconstruction, where only data corresponding to a certain motion state are incorporated. Another one is motioncompensated reconstruction with a pre-computed motion vector field, which requires a preceding estimation of the motion. Here, results of a new approach are presented: simultaneous reconstruction of a three-dimensional object and its motion over time, yielding a fully four-dimensional representation. The object motion is modeled by a time-dependent elastic transformation. The reconstruction is carried out with an iterative gradient-descent algorithm which simultaneously optimizes the three-dimensional image and the motion parameters. The method was tested on a simulated rotational X-ray acquisition of a dynamic coronary artery phantom, acquired on a C-arm system with a slowly rotating C-arm. Accurate reconstruction of both absorption coefficient and motion could be achieved. First results from experiments on clinical rotational X-ray coronary angiography data are shown. The resulting reconstructions enable the analysis of both static properties, such as vessel geometry and cross-sectional areas, and dynamic properties, like magnitude, speed, and synchrony of motion during the cardiac cycle.

  14. Direct 4D PET MLEM reconstruction of parametric images using the simplified reference tissue model with the basis function method for [¹¹C]raclopride.

    PubMed

    Gravel, Paul; Reader, Andrew J

    2015-06-01

    This work assesses the one-step late maximum likelihood expectation maximization (OSL-MLEM) 4D PET reconstruction algorithm for direct estimation of parametric images from raw PET data when using the simplified reference tissue model with the basis function method (SRTM-BFM) for the kinetic analysis. To date, the OSL-MLEM method has been evaluated using kinetic models based on two-tissue compartments with an irreversible component. We extend the evaluation of this method for two-tissue compartments with a reversible component, using SRTM-BFM on simulated 3D + time data sets (with use of [(11)C]raclopride time-activity curves from real data) and on real data sets acquired with the high resolution research tomograph. The performance of the proposed method is evaluated by comparing voxel-level binding potential (BPND) estimates with those obtained from conventional post-reconstruction kinetic parameter estimation. For the commonly chosen number of iterations used in practice, our results show that for the 3D + time simulation, the direct method delivers results with lower (%)RMSE at the normal count level (decreases of 9-10 percentage points, corresponding to a 38-44% reduction), and also at low count levels (decreases of 17-21 percentage points, corresponding to a 26-36% reduction). As for the real 3D data set, the results obtained follow a similar trend, with the direct reconstruction method offering a 21% decrease in (%)CV compared to the post reconstruction method at low count levels. Thus, based on the results presented herein, using the SRTM-BFM kinetic model in conjunction with the OSL-MLEM direct 4D PET MLEM reconstruction method offers an improvement in performance when compared to conventional post reconstruction methods. PMID:25992999

  15. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET

    NASA Astrophysics Data System (ADS)

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the ‘almost’ noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  16. Non-rigid dual respiratory and cardiac motion correction methods after, during, and before image reconstruction for 4D cardiac PET.

    PubMed

    Feng, Tao; Wang, Jizhe; Fung, George; Tsui, Benjamin

    2016-01-01

    Respiratory motion (RM) and cardiac motion (CM) degrade the quality and resolution in cardiac PET scans. We have developed non-rigid motion estimation methods to estimate both RM and CM based on 4D cardiac gated PET data alone, and compensate the dual respiratory and cardiac (R&C) motions after (MCAR), during (MCDR), and before (MCBR) image reconstruction. In all three R&C motion correction methods, attenuation-activity mismatch effect was modeled by using transformed attenuation maps using the estimated RM. The difference of using activity preserving and non-activity preserving models in R&C correction was also studied. Realistic Monte Carlo simulated 4D cardiac PET data using the 4D XCAT phantom and accurate models of the scanner design parameters and performance characteristics at different noise levels were employed as the known truth and for method development and evaluation. Results from the simulation study suggested that all three dual R&C motion correction methods provide substantial improvement in the quality of 4D cardiac gated PET images as compared with no motion correction. Specifically, the MCDR method yields the best performance for all different noise levels compared with the MCAR and MCBR methods. While MCBR reduces computational time dramatically but the resultant 4D cardiac gated PET images has overall inferior image quality when compared to that from the MCAR and MCDR approaches in the 'almost' noise free case. Also, the MCBR method has better noise handling properties when compared with MCAR and provides better quantitative results in high noise cases. When the goal is to reduce scan time or patient radiation dose, MCDR and MCBR provide a good compromise between image quality and computational times.

  17. Joint surface reconstruction and 4D deformation estimation from sparse data and prior knowledge for marker-less Respiratory motion tracking

    SciTech Connect

    Berkels, Benjamin; Rumpf, Martin; Bauer, Sebastian; Ettl, Svenja; Arold, Oliver; Hornegger, Joachim

    2013-09-15

    Purpose: The intraprocedural tracking of respiratory motion has the potential to substantially improve image-guided diagnosis and interventions. The authors have developed a sparse-to-dense registration approach that is capable of recovering the patient's external 3D body surface and estimating a 4D (3D + time) surface motion field from sparse sampling data and patient-specific prior shape knowledge.Methods: The system utilizes an emerging marker-less and laser-based active triangulation (AT) sensor that delivers sparse but highly accurate 3D measurements in real-time. These sparse position measurements are registered with a dense reference surface extracted from planning data. Thereby a dense displacement field is recovered, which describes the spatio-temporal 4D deformation of the complete patient body surface, depending on the type and state of respiration. It yields both a reconstruction of the instantaneous patient shape and a high-dimensional respiratory surrogate for respiratory motion tracking. The method is validated on a 4D CT respiration phantom and evaluated on both real data from an AT prototype and synthetic data sampled from dense surface scans acquired with a structured-light scanner.Results: In the experiments, the authors estimated surface motion fields with the proposed algorithm on 256 datasets from 16 subjects and in different respiration states, achieving a mean surface reconstruction accuracy of ±0.23 mm with respect to ground truth data—down from a mean initial surface mismatch of 5.66 mm. The 95th percentile of the local residual mesh-to-mesh distance after registration did not exceed 1.17 mm for any subject. On average, the total runtime of our proof of concept CPU implementation is 2.3 s per frame, outperforming related work substantially.Conclusions: In external beam radiation therapy, the approach holds potential for patient monitoring during treatment using the reconstructed surface, and for motion-compensated dose delivery using

  18. 3D-Reconstructions and Virtual 4D-Visualization to Study Metamorphic Brain Development in the Sphinx Moth Manduca Sexta.

    PubMed

    Huetteroth, Wolf; El Jundi, Basil; El Jundi, Sirri; Schachtner, Joachim

    2010-01-01

    DURING METAMORPHOSIS, THE TRANSITION FROM THE LARVA TO THE ADULT, THE INSECT BRAIN UNDERGOES CONSIDERABLE REMODELING: new neurons are integrated while larval neurons are remodeled or eliminated. One well acknowledged model to study metamorphic brain development is the sphinx moth Manduca sexta. To further understand mechanisms involved in the metamorphic transition of the brain we generated a 3D standard brain based on selected brain areas of adult females and 3D reconstructed the same areas during defined stages of pupal development. Selected brain areas include for example mushroom bodies, central complex, antennal- and optic lobes. With this approach we eventually want to quantify developmental changes in neuropilar architecture, but also quantify changes in the neuronal complement and monitor the development of selected neuronal populations. Furthermore, we used a modeling software (Cinema 4D) to create a virtual 4D brain, morphing through its developmental stages. Thus the didactical advantages of 3D visualization are expanded to better comprehend complex processes of neuropil formation and remodeling during development. To obtain datasets of the M. sexta brain areas, we stained whole brains with an antiserum against the synaptic vesicle protein synapsin. Such labeled brains were then scanned with a confocal laser scanning microscope and selected neuropils were reconstructed with the 3D software AMIRA 4.1.

  19. An accelerated and convergent iterative algorithm in image reconstruction

    NASA Astrophysics Data System (ADS)

    Yan, Jianhua; Yu, Jun

    2007-05-01

    Positron emission tomography (PET) is becoming increasingly important in the field of medicine and biology. The maximum-likelihood expectation-maximization (ML-EM) algorithm is becoming more important than filtered back-projection (FBP) algorithm which can incorporate various physical models into image reconstruction scheme. However, ML-EM converges slowly. In this paper, we propose a new algorithm named AC-ML-EM (accelerated and convergent maximum likelihood expectation maximization) by introducing gradually decreasing correction factor into ML-EM. AC-ML-EM has a higher speed of convergence. Through the experiments of computer simulated phantom data and real phantom data, AC-ML-EM is shown faster and better quantitatively than conventional ML-EM algorithm.

  20. Advances in 4D radiation therapy for managing respiration: part I - 4D imaging.

    PubMed

    Hugo, Geoffrey D; Rosu, Mihaela

    2012-12-01

    Techniques for managing respiration during imaging and planning of radiation therapy are reviewed, concentrating on free-breathing (4D) approaches. First, we focus on detailing the historical development and basic operational principles of currently-available "first generation" 4D imaging modalities: 4D computed tomography, 4D cone beam computed tomography, 4D magnetic resonance imaging, and 4D positron emission tomography. Features and limitations of these first generation systems are described, including necessity of breathing surrogates for 4D image reconstruction, assumptions made in acquisition and reconstruction about the breathing pattern, and commonly-observed artifacts. Both established and developmental methods to deal with these limitations are detailed. Finally, strategies to construct 4D targets and images and, alternatively, to compress 4D information into static targets and images for radiation therapy planning are described.

  1. Advances in 4D Radiation Therapy for Managing Respiration: Part I – 4D Imaging

    PubMed Central

    Hugo, Geoffrey D.; Rosu, Mihaela

    2014-01-01

    Techniques for managing respiration during imaging and planning of radiation therapy are reviewed, concentrating on free-breathing (4D) approaches. First, we focus on detailing the historical development and basic operational principles of currently-available “first generation” 4D imaging modalities: 4D computed tomography, 4D cone beam computed tomography, 4D magnetic resonance imaging, and 4D positron emission tomography. Features and limitations of these first generation systems are described, including necessity of breathing surrogates for 4D image reconstruction, assumptions made in acquisition and reconstruction about the breathing pattern, and commonly-observed artifacts. Both established and developmental methods to deal with these limitations are detailed. Finally, strategies to construct 4D targets and images and, alternatively, to compress 4D information into static targets and images for radiation therapy planning are described. PMID:22784929

  2. 4-D Photoacoustic Tomography

    NASA Astrophysics Data System (ADS)

    Xiang, Liangzhong; Wang, Bo; Ji, Lijun; Jiang, Huabei

    2013-01-01

    Photoacoustic tomography (PAT) offers three-dimensional (3D) structural and functional imaging of living biological tissue with label-free, optical absorption contrast. These attributes lend PAT imaging to a wide variety of applications in clinical medicine and preclinical research. Despite advances in live animal imaging with PAT, there is still a need for 3D imaging at centimeter depths in real-time. We report the development of four dimensional (4D) PAT, which integrates time resolutions with 3D spatial resolution, obtained using spherical arrays of ultrasonic detectors. The 4D PAT technique generates motion pictures of imaged tissue, enabling real time tracking of dynamic physiological and pathological processes at hundred micrometer-millisecond resolutions. The 4D PAT technique is used here to image needle-based drug delivery and pharmacokinetics. We also use this technique to monitor 1) fast hemodynamic changes during inter-ictal epileptic seizures and 2) temperature variations during tumor thermal therapy.

  3. 4D Electron Tomography

    NASA Astrophysics Data System (ADS)

    Kwon, Oh-Hoon; Zewail, Ahmed H.

    2010-06-01

    Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.

  4. Interactive animation of 4D performance capture.

    PubMed

    Casas, Dan; Tejera, Margara; Guillemaut, Jean-Yves; Hilton, Adrian

    2013-05-01

    A 4D parametric motion graph representation is presented for interactive animation from actor performance capture in a multiple camera studio. The representation is based on a 4D model database of temporally aligned mesh sequence reconstructions for multiple motions. High-level movement controls such as speed and direction are achieved by blending multiple mesh sequences of related motions. A real-time mesh sequence blending approach is introduced, which combines the realistic deformation of previous nonlinear solutions with efficient online computation. Transitions between different parametric motion spaces are evaluated in real time based on surface shape and motion similarity. Four-dimensional parametric motion graphs allow real-time interactive character animation while preserving the natural dynamics of the captured performance.

  5. Interactive animation of 4D performance capture.

    PubMed

    Casas, Dan; Tejera, Margara; Guillemaut, Jean-Yves; Hilton, Adrian

    2013-05-01

    A 4D parametric motion graph representation is presented for interactive animation from actor performance capture in a multiple camera studio. The representation is based on a 4D model database of temporally aligned mesh sequence reconstructions for multiple motions. High-level movement controls such as speed and direction are achieved by blending multiple mesh sequences of related motions. A real-time mesh sequence blending approach is introduced, which combines the realistic deformation of previous nonlinear solutions with efficient online computation. Transitions between different parametric motion spaces are evaluated in real time based on surface shape and motion similarity. Four-dimensional parametric motion graphs allow real-time interactive character animation while preserving the natural dynamics of the captured performance. PMID:23492379

  6. Soft Route to 4D Tomography.

    PubMed

    Taillandier-Thomas, Thibault; Roux, Stéphane; Hild, François

    2016-07-01

    Based on the assumption that the time evolution of a sample observed by computed tomography requires many less parameters than the definition of the microstructure itself, it is proposed to reconstruct these changes based on the initial state (using computed tomography) and very few radiographs acquired at fixed intervals of time. This Letter presents a proof of concept that for a fatigue cracked sample its kinematics can be tracked from no more than two radiographs in situations where a complete 3D view would require several hundreds of radiographs. This 2 order of magnitude gain opens the way to a "computed" 4D tomography, which complements the recent progress achieved in fast or ultrafast computed tomography, which is based on beam brightness, detector sensitivity, and signal acquisition technologies.

  7. Soft Route to 4D Tomography

    NASA Astrophysics Data System (ADS)

    Taillandier-Thomas, Thibault; Roux, Stéphane; Hild, François

    2016-07-01

    Based on the assumption that the time evolution of a sample observed by computed tomography requires many less parameters than the definition of the microstructure itself, it is proposed to reconstruct these changes based on the initial state (using computed tomography) and very few radiographs acquired at fixed intervals of time. This Letter presents a proof of concept that for a fatigue cracked sample its kinematics can be tracked from no more than two radiographs in situations where a complete 3D view would require several hundreds of radiographs. This 2 order of magnitude gain opens the way to a "computed" 4D tomography, which complements the recent progress achieved in fast or ultrafast computed tomography, which is based on beam brightness, detector sensitivity, and signal acquisition technologies.

  8. 4D-DSA and 4D fluoroscopy: preliminary implementation

    NASA Astrophysics Data System (ADS)

    Mistretta, C. A.; Oberstar, E.; Davis, B.; Brodsky, E.; Strother, C. M.

    2010-04-01

    We have described methods that allow highly accelerated MRI using under-sampled acquisitions and constrained reconstruction. One is a hybrid acquisition involving the constrained reconstruction of time dependent information obtained from a separate scan of longer duration. We have developed reconstruction algorithms for DSA that allow use of a single injection to provide the temporal data required for flow visualization and the steady state data required for construction of a 3D-DSA vascular volume. The result is time resolved 3D volumes with typical resolution of 5123 at frame rates of 20-30 fps. Full manipulation of these images is possible during each stage of vascular filling thereby allowing for simplified interpretation of vascular dynamics. For intravenous angiography this time resolved 3D capability overcomes the vessel overlap problem that greatly limited the use of conventional intravenous 2D-DSA. Following further hardware development, it will be also be possible to rotate fluoroscopic volumes for use as roadmaps that can be viewed at arbitrary angles without a need for gantry rotation. The most precise implementation of this capability requires availability of biplane fluoroscopy data. Since the reconstruction of 3D volumes presently suppresses the contrast in the soft tissue, the possibility of using these techniques to derive complete indications of perfusion deficits based on cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) parameters requires further investigation. Using MATLAB post-processing, successful studies in animals and humans done in conjunction with both intravenous and intra-arterial injections have been completed. Real time implementation is in progress.

  9. 4-D ultrafast shear-wave imaging.

    PubMed

    Gennisson, Jean-Luc; Provost, Jean; Deffieux, Thomas; Papadacci, Clément; Imbault, Marion; Pernot, Mathieu; Tanter, Mickael

    2015-06-01

    Over the last ten years, shear wave elastography (SWE) has seen considerable development and is now routinely used in clinics to provide mechanical characterization of tissues to improve diagnosis. The most advanced technique relies on the use of an ultrafast scanner to generate and image shear waves in real time in a 2-D plane at several thousands of frames per second. We have recently introduced 3-D ultrafast ultrasound imaging to acquire with matrix probes the 3-D propagation of shear waves generated by a dedicated radiation pressure transducer in a single acquisition. In this study, we demonstrate 3-D SWE based on ultrafast volumetric imaging in a clinically applicable configuration. A 32 × 32 matrix phased array driven by a customized, programmable, 1024-channel ultrasound system was designed to perform 4-D shear-wave imaging. A matrix phased array was used to generate and control in 3-D the shear waves inside the medium using the acoustic radiation force. The same matrix array was used with 3-D coherent plane wave compounding to perform high-quality ultrafast imaging of the shear wave propagation. Volumetric ultrafast acquisitions were then beamformed in 3-D using a delay-and-sum algorithm. 3-D volumetric maps of the shear modulus were reconstructed using a time-of-flight algorithm based on local multiscale cross-correlation of shear wave profiles in the three main directions using directional filters. Results are first presented in an isotropic homogeneous and elastic breast phantom. Then, a full 3-D stiffness reconstruction of the breast was performed in vivo on healthy volunteers. This new full 3-D ultrafast ultrasound system paves the way toward real-time 3-D SWE. PMID:26067040

  10. A 4D Hyperspherical Interpretation of q-Space

    PubMed Central

    Hosseinbor, A. Pasha; Chung, Moo K.; Wu, Yu-Chien; Alexander, Andrew L.; Bendlin, Barbara B.

    2014-01-01

    3D q-space can be viewed as the surface of a 4D hypersphere. In this paper, we seek to develop a 4D hyperspherical interpretation of q-space by projecting it onto a hypersphere and subsequently modeling the q-space signal via 4D hyperspherical harmonics (HSH). Using this orthonormal basis, we analytically derive several quantitative indices and numerically estimate the diffusion ODF. Importantly, we derive the integral transform describing the relationship between the diffusion signal and propagator on a hypersphere. We also show that the HSH basis expends less fitting parameters than other well-established methods to achieve comparable signal and better ODF reconstructions. All in all, this work provides a new way of looking at q-space. PMID:24505799

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

    PubMed Central

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

    2013-01-01

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

  12. Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy

    NASA Astrophysics Data System (ADS)

    Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

    2016-06-01

    A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra-reconstruction

  13. Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy.

    PubMed

    Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

    2016-06-01

    A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra-reconstruction

  14. 4-D OCT in Developmental Cardiology

    NASA Astrophysics Data System (ADS)

    Jenkins, Michael W.; Rollins, Andrew M.

    Although strong evidence exists to suggest that altered cardiac function can lead to CHDs, few studies have investigated the influential role of cardiac function and biophysical forces on the development of the cardiovascular system due to a lack of proper in vivo imaging tools. 4-D imaging is needed to decipher the complex spatial and temporal patterns of biomechanical forces acting upon the heart. Numerous solutions over the past several years have demonstrated 4-D OCT imaging of the developing cardiovascular system. This chapter will focus on these solutions and explain their context in the evolution of 4-D OCT imaging. The first sections describe the relevant techniques (prospective gating, direct 4-D imaging, retrospective gating), while later sections focus on 4-D Doppler imaging and measurements of force implementing 4-D OCT Doppler. Finally, the techniques are summarized, and some possible future directions are discussed.

  15. A 4D Hyperspherical Interpretation of q-Space

    PubMed Central

    Hosseinbor, A. Pasha; Chung, Moo K.; Wu, Yu-Chien; Bendlin, Barbara B.; Alexander, Andrew L.

    2015-01-01

    3D q-space can be viewed as the surface of a 4D hypersphere. In this paper, we seek to develop a 4D hyperspherical interpretation of q-space by projecting it onto a hypersphere and subsequently modeling the q-space signal via 4D hyperspherical harmonics (HSH). Using this orthonormal basis, we derive several well-established q-space indices and numerically estimate the diffusion orientation distribution function (dODF). We also derive the integral transform describing the relationship between the diffusion signal and propagator on a hypersphere. Most importantly, we will demonstrate that for hybrid diffusion imaging (HYDI) acquisitions low order linear expansion of the HSH basis is sufficient to characterize diffusion in neural tissue. In fact, the HSH basis achieves comparable signal and better dODF reconstructions than other well-established methods, such as Bessel Fourier orientation reconstruction (BFOR), using fewer fitting parameters. All in all, this work provides a new way of looking at q-space. PMID:25624043

  16. Brain tissue segmentation in 4D CT using voxel classification

    NASA Astrophysics Data System (ADS)

    van den Boom, R.; Oei, M. T. H.; Lafebre, S.; Oostveen, L. J.; Meijer, F. J. A.; Steens, S. C. A.; Prokop, M.; van Ginneken, B.; Manniesing, R.

    2012-02-01

    A method is proposed to segment anatomical regions of the brain from 4D computer tomography (CT) patient data. The method consists of a three step voxel classification scheme, each step focusing on structures that are increasingly difficult to segment. The first step classifies air and bone, the second step classifies vessels and the third step classifies white matter, gray matter and cerebrospinal fluid. As features the time averaged intensity value and the temporal intensity change value were used. In each step, a k-Nearest-Neighbor classifier was used to classify the voxels. Training data was obtained by placing regions of interest in reconstructed 3D image data. The method has been applied to ten 4D CT cerebral patient data. A leave-one-out experiment showed consistent and accurate segmentation results.

  17. Los Alamos National Laboratory 4D Database

    SciTech Connect

    Atencio, Julian J.

    2014-05-02

    4D is an integrated development platform - a single product comprised of the components you need to create and distribute professional applications. You get a graphical design environment, SQL database, a programming language, integrated PHP execution, HTTP server, application server, executable generator, and much more. 4D offers multi-platform development and deployment, meaning whatever you create on a Mac can be used on Windows, and vice-versa. Beyond productive development, 4D is renowned for its great flexibility in maintenance and modification of existing applications, and its extreme ease of implementation in its numerous deployment options. Your professional application can be put into production more quickly, at a lower cost, and will always be instantly scalable. 4D makes it easy, whether you're looking to create a classic desktop application, a client-server system, a distributed solution for Web or mobile clients - or all of the above!

  18. Founding Gravitation in 4D Euclidean Space-Time Geometry

    SciTech Connect

    Winkler, Franz-Guenter

    2010-11-24

    The Euclidean interpretation of special relativity which has been suggested by the author is a formulation of special relativity in ordinary 4D Euclidean space-time geometry. The natural and geometrically intuitive generalization of this view involves variations of the speed of light (depending on location and direction) and a Euclidean principle of general covariance. In this article, a gravitation model by Jan Broekaert, which implements a view of relativity theory in the spirit of Lorentz and Poincare, is reconstructed and shown to fulfill the principles of the Euclidean approach after an appropriate reinterpretation.

  19. Helical 4D CT and Comparison with Cine 4D CT

    NASA Astrophysics Data System (ADS)

    Pan, Tinsu

    4D CT was one of the most important developments in radiation oncology in the last decade. Its early development in single slice CT and commercialization in multi-slice CT has radically changed our practice in radiation treatment of lung cancer, and has enabled the stereotactic radiosurgery of early stage lung cancer. In this chapter, we will document the history of 4D CT development, detail the data sufficiency condition governing the 4D CT data collection; present the design of the commercial helical 4D CTs from Philips and Siemens; compare the differences between the helical 4D CT and the GE cine 4D CT in data acquisition, slice thickness, acquisition time and work flow; review the respiratory monitoring devices; and understand the causes of image artifacts in 4D CT.

  20. 4D flow mri post-processing strategies for neuropathologies

    NASA Astrophysics Data System (ADS)

    Schrauben, Eric Mathew

    double-gated flow acquisition and reconstruction scheme demonstrates respiratory-induced changes in internal jugular vein flow. Finally, a semi-automated intracranial vessel segmentation and flow parameter measurement software tool for fast and consistent 4D flow post-processing analysis is developed, validated, and exhibited an in-vivo.

  1. 4D flow imaging with MRI

    PubMed Central

    Stankovic, Zoran; Allen, Bradley D.; Garcia, Julio; Jarvis, Kelly B.

    2014-01-01

    Magnetic resonance imaging (MRI) has become an important tool for the clinical evaluation of patients with cardiovascular disease. Since its introduction in the late 1980s, 2-dimensional phase contrast MRI (2D PC-MRI) has become a routine part of standard-of-care cardiac MRI for the assessment of regional blood flow in the heart and great vessels. More recently, time-resolved PC-MRI with velocity encoding along all three flow directions and three-dimensional (3D) anatomic coverage (also termed ‘4D flow MRI’) has been developed and applied for the evaluation of cardiovascular hemodynamics in multiple regions of the human body. 4D flow MRI allows for the comprehensive evaluation of complex blood flow patterns by 3D blood flow visualization and flexible retrospective quantification of flow parameters. Recent technical developments, including the utilization of advanced parallel imaging techniques such as k-t GRAPPA, have resulted in reasonable overall scan times, e.g., 8-12 minutes for 4D flow MRI of the aorta and 10-20 minutes for whole heart coverage. As a result, the application of 4D flow MRI in a clinical setting has become more feasible, as documented by an increased number of recent reports on the utility of the technique for the assessment of cardiac and vascular hemodynamics in patient studies. A number of studies have demonstrated the potential of 4D flow MRI to provide an improved assessment of hemodynamics which might aid in the diagnosis and therapeutic management of cardiovascular diseases. The purpose of this review is to describe the methods used for 4D flow MRI acquisition, post-processing and data analysis. In addition, the article provides an overview of the clinical applications of 4D flow MRI and includes a review of applications in the heart, thoracic aorta and hepatic system. PMID:24834414

  2. Phosphodiesterase4D (PDE4D)--A risk factor for atrial fibrillation and stroke?

    PubMed

    Jørgensen, Carina; Yasmeen, Saiqa; Iversen, Helle K; Kruuse, Christina

    2015-12-15

    Mutations in the gene encoding phosphodiesterase 4D (PDE4D) enzyme are associated with ischemic stroke; however the functional implications of such mutations are not well understood. PDE4D is part of a complex protein family modulating intracellular signalling by cyclic nucleotides. The PDE4 family includes subtypes A-D, all of which show unique intracellular, cellular and tissue distribution. PDE4D is the major subtype expressed in human atrial myocytes and involved in the pathophysiology of arrhythmias, such as atrial fibrillation. The PDE4D enzyme hydrolyses cyclic adenosine monophosphate (cAMP). Though diverging results are reported, several population based studies describe association of various PDE4D single nucleotide polymorphisms (SNP) with cardio-embolic stroke in particular. Functionally, a down regulation of PDE4D variants has been reported in stroke patients. The anti-inflammatory and vasodilator properties of PDE4 inhibitors make them suitable for treatment of stroke and cardiovascular disease. PDE4D has recently been suggested as factor in atrial fibrillation. This review summarizes the possible function of PDE4D in the brain, heart, and vasculature. Further, association of the described SNPs, in particular, with cardioembolic stroke, is reviewed. Current findings on the PDE4D mutations suggest functionality involves an increased cardiac risk factor as well as augmented risk of atrial fibrillation. PMID:26671126

  3. Actively triggered 4d cone-beam CT acquisition

    SciTech Connect

    Fast, Martin F.; Wisotzky, Eric; Oelfke, Uwe; Nill, Simeon

    2013-09-15

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

  4. Shadow-driven 4D haptic visualization.

    PubMed

    Zhang, Hui; Hanson, Andrew

    2007-01-01

    Just as we can work with two-dimensional floor plans to communicate 3D architectural design, we can exploit reduced-dimension shadows to manipulate the higher-dimensional objects generating the shadows. In particular, by taking advantage of physically reactive 3D shadow-space controllers, we can transform the task of interacting with 4D objects to a new level of physical reality. We begin with a teaching tool that uses 2D knot diagrams to manipulate the geometry of 3D mathematical knots via their projections; our unique 2D haptic interface allows the user to become familiar with sketching, editing, exploration, and manipulation of 3D knots rendered as projected imageson a 2D shadow space. By combining graphics and collision-sensing haptics, we can enhance the 2D shadow-driven editing protocol to successfully leverage 2D pen-and-paper or blackboard skills. Building on the reduced-dimension 2D editing tool for manipulating 3D shapes, we develop the natural analogy to produce a reduced-dimension 3D tool for manipulating 4D shapes. By physically modeling the correct properties of 4D surfaces, their bending forces, and their collisions in the 3D haptic controller interface, we can support full-featured physical exploration of 4D mathematical objects in a manner that is otherwise far beyond the experience accessible to human beings. As far as we are aware, this paper reports the first interactive system with force-feedback that provides "4D haptic visualization" permitting the user to model and interact with 4D cloth-like objects.

  5. 4D Confocal Imaging of Yeast Organelles.

    PubMed

    Day, Kasey J; Papanikou, Effrosyni; Glick, Benjamin S

    2016-01-01

    Yeast cells are well suited to visualizing organelles by 4D confocal microscopy. Typically, one or more cellular compartments are labeled with a fluorescent protein or dye, and a stack of confocal sections spanning the entire cell volume is captured every few seconds. Under appropriate conditions, organelle dynamics can be observed for many minutes with only limited photobleaching. Images are captured at a relatively low signal-to-noise ratio and are subsequently processed to generate movies that can be analyzed and quantified. Here, we describe methods for acquiring and processing 4D data using conventional scanning confocal microscopy. PMID:27631997

  6. The scientific value of 4D visualizations

    NASA Astrophysics Data System (ADS)

    Minster, J.; Olsen, K.; Day, S.; Moore, R.; Jordan, T. H.; Maechling, P.; Chourasia, A.

    2006-12-01

    Significant scientific insights derive from viewing measured, or calculated three-dimensional, time-dependent -- that is four-dimensional-- fields. This issue cuts across all disciplines of Earth Sciences. Addressing it calls for close collaborations between "domain" scientists and "IT" visualization specialists. Techniques to display such 4D fields in a intuitive way are a major challenge, especially when the relevant variables to be displayed are not scalars but tensors. This talk will illustrate some attempts to deal with this challenge, using seismic wave fields as specific objects to display. We will highlight how 4D displays can help address very difficult issues of significant scientific import.

  7. 4D-Var Developement at GMAO

    NASA Technical Reports Server (NTRS)

    Pelc, Joanna S.; Todling, Ricardo; Akkraoui, Amal El

    2014-01-01

    The Global Modeling and Assimilation Offce (GMAO) is currently using an IAU-based 3D-Var data assimilation system. GMAO has been experimenting with a 3D-Var-hybrid version of its data assimilation system (DAS) for over a year now, which will soon become operational and it will rapidly progress toward a 4D-EnVar. Concurrently, the machinery to exercise traditional 4DVar is in place and it is desirable to have a comparison of the traditional 4D approach with the other available options, and evaluate their performance in the Goddard Earth Observing System (GEOS) DAS. This work will also explore the possibility for constructing a reduced order model (ROM) to make traditional 4D-Var computationally attractive for increasing model resolutions. Part of the research on ROM will be to search for a suitably acceptable space to carry on the corresponding reduction. This poster illustrates how the IAU-based 4D-Var assimilation compares with our currently used IAU-based 3D-Var.

  8. Nondipole Effects in Xe 4d Photoemission

    SciTech Connect

    Hemmers, O; Guillemin, R; Wolska, A; Lindle, D W; Rolles, D; Cheng, K T; Johnson, W R; Zhou, H L; Manson, S T

    2004-07-14

    We measured the nondipole parameters for the spin-orbit doublets Xe 4d{sub 5/2} and Xe 4d{sub 3/2} over a photon-energy range from 100 eV to 250 eV at beamline 8.0.1.3 of the Advanced Light Source at the Lawrence Berkeley National Laboratory. Significant nondipole effects are found at relatively low energies as a result of Cooper minima in dipole channels and interchannel coupling in quadrupole channels. Most importantly, sharp disagreement between experiment and theory, when otherwise excellent agreement was expected, has provided the first evidence of satellite two-electron quadrupole photoionization transitions, along with their crucial importance for a quantitatively accurate theory.

  9. Three Dimensional Iterative Reconstruction Techniques in Positron Tomography.

    NASA Astrophysics Data System (ADS)

    Sloka, Scott

    The acquisition of positron tomographic data in three dimensions is an improvement over the two dimensional acquisition of data because the greater the number of measurements taken of a stochastic process, the more accurately determined the desired parameter may be. This research pursues the goal of three dimensional image reconstruction in Positron Tomography using an iterative approach. This thesis has followed a systematic approach to the exploration of a system for three dimensional iterative reconstruction. System design parameters were discussed such as the advantages and disadvantages of iterative vs analytic methods, the implementation of two, three dimensional iterative algorithms, the selection of a ray passing method, and the choice of an analytic method for comparison to the iterative methods. Several qualitative and quantitative tests were used/developed and performed to analyse and compare the results. Three dimensional reconstruction in Positron Tomography using two iterative techniques (ART and ML-EM) was demonstrated. The ML-EM algorithm was adapted to satisfy the objective of equalizing the estimates with the measurements via division of the sampling density. A new multi-objective function methodology was developed for two dimensions and its extension to three dimensions discussed. A smoothly-varying Gaussian phantom was created for comparing artifacts from different ray passing methods. The analysis of voxel trends over many iterations was used. The use of the output from a two dimensional filtered backprojection algorithm as the seed for three dimensional algorithms to accelerate the reconstruction the was explored. The importance of the selection of a good ray ordering in ART and its effects on the total squared error were explored. For the phantoms studied in this thesis, the ML -EM algorithm tended to perform better under most conditions. This algorithm is slower than ART to achieve both a low total squared error and good contrast, but the

  10. Noise reduction in computed tomography using a multiplicative continuous-time image reconstruction method

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yusaku; Kojima, Takeshi; Yoshinaga, Tetsuya

    2016-03-01

    In clinical X-ray computed tomography (CT), filtered back-projection as a transform method and iterative reconstruction such as the maximum-likelihood expectation-maximization (ML-EM) method are known methods to reconstruct tomographic images. As the other reconstruction method, we have presented a continuous-time image reconstruction (CIR) system described by a nonlinear dynamical system, based on the idea of continuous methods for solving tomographic inverse problems. Recently, we have also proposed a multiplicative CIR system described by differential equations based on the minimization of a weighted Kullback-Leibler divergence. We prove theoretically that the divergence measure decreases along the solution to the CIR system, for consistent inverse problems. In consideration of the noisy nature of projections in clinical CT, the inverse problem belongs to the category of ill-posed problems. The performance of a noise-reduction scheme for a new (previously developed) CIR system was investigated by means of numerical experiments using a circular phantom image. Compared to the conventional CIR and the ML-EM methods, the proposed CIR method has an advantage on noisy projection with lower signal-to-noise ratios in terms of the divergence measure on the actual image under the same common measure observed via the projection data. The results lead to the conclusion that the multiplicative CIR method is more effective and robust for noise reduction in CT compared to the ML-EM as well as conventional CIR methods.

  11. Geometric validation of self-gating k-space-sorted 4D-MRI vs 4D-CT using a respiratory motion phantom

    SciTech Connect

    Yue, Yong Yang, Wensha; McKenzie, Elizabeth; Tuli, Richard; Wallace, Robert; Fraass, Benedick; Fan, Zhaoyang; Pang, Jianing; Deng, Zixin; Li, Debiao

    2015-10-15

    Purpose: MRI is increasingly being used for radiotherapy planning, simulation, and in-treatment-room motion monitoring. To provide more detailed temporal and spatial MR data for these tasks, we have recently developed a novel self-gated (SG) MRI technique with advantage of k-space phase sorting, high isotropic spatial resolution, and high temporal resolution. The current work describes the validation of this 4D-MRI technique using a MRI- and CT-compatible respiratory motion phantom and comparison to 4D-CT. Methods: The 4D-MRI sequence is based on a spoiled gradient echo-based 3D projection reconstruction sequence with self-gating for 4D-MRI at 3 T. Respiratory phase is resolved by using SG k-space lines as the motion surrogate. 4D-MRI images are reconstructed into ten temporal bins with spatial resolution 1.56 × 1.56 × 1.56 mm{sup 3}. A MRI-CT compatible phantom was designed to validate the performance of the 4D-MRI sequence and 4D-CT imaging. A spherical target (diameter 23 mm, volume 6.37 ml) filled with high-concentration gadolinium (Gd) gel is embedded into a plastic box (35 × 40 × 63 mm{sup 3}) and stabilized with low-concentration Gd gel. The phantom, driven by an air pump, is able to produce human-type breathing patterns between 4 and 30 respiratory cycles/min. 4D-CT of the phantom has been acquired in cine mode, and reconstructed into ten phases with slice thickness 1.25 mm. The 4D images sets were imported into a treatment planning software for target contouring. The geometrical accuracy of the 4D MRI and CT images has been quantified using target volume, flattening, and eccentricity. The target motion was measured by tracking the centroids of the spheres in each individual phase. Motion ground-truth was obtained from input signals and real-time video recordings. Results: The dynamic phantom has been operated in four respiratory rate (RR) settings, 6, 10, 15, and 20/min, and was scanned with 4D-MRI and 4D-CT. 4D-CT images have target

  12. Abdominal and pancreatic motion correlation using 4D CT, 4D transponders, and a gating belt.

    PubMed

    Betancourt, Ricardo; Zou, Wei; Plastaras, John P; Metz, James M; Teo, Boon-Keng; Kassaee, Alireza

    2013-01-01

    The correlation between the pancreatic and external abdominal motion due to respiration was investigated on two patients. These studies utilized four dimensional computer tomography (4D CT), a four dimensional (4D) electromagnetic transponder system, and a gating belt system. One 4D CT study was performed during simulation to quantify the pancreatic motion using computer tomography images at eight breathing phases. The motion under free breathing and breath-hold were analyzed for the 4D electromagnetic transponder system and the gating belt system during treatment. A linear curve was fitted for all data sets and correlation factors were evaluated between the 4D electromagnetic transponder system and the gating belt system data. The 4D CT study demonstrated a modest correlation between the external marker and the pancreatic motion with R-square values larger than 0.8 for the inferior-superior (inf-sup). Then, the relative pressure from the belt gating system correlated well with the 4D electromagnetic transponder system's motion in the anterior-posterior (ant-post) and the inf-post directions. These directions have a correlation value of -0.93 and 0.76, while the lateral only had a 0.03 correlation coefficient. Based on our limited study, external surrogates can be used as predictors of the pancreatic motion in the inf-sup and the ant-post directions. Although there is a low correlation on the lateral direction, its motion is significantly shorter. In conclusion, an appropriate treatment delivery can be used for pancreatic cancer when an internal tracking system, such as the 4D electromagnetic transponder system, is unavailable. PMID:23652242

  13. Abdominal and pancreatic motion correlation using 4D CT, 4D transponders, and a gating belt.

    PubMed

    Betancourt, Ricardo; Zou, Wei; Plastaras, John P; Metz, James M; Teo, Boon-Keng; Kassaee, Alireza

    2013-05-06

    The correlation between the pancreatic and external abdominal motion due to respiration was investigated on two patients. These studies utilized four dimensional computer tomography (4D CT), a four dimensional (4D) electromagnetic transponder system, and a gating belt system. One 4D CT study was performed during simulation to quantify the pancreatic motion using computer tomography images at eight breathing phases. The motion under free breathing and breath-hold were analyzed for the 4D electromagnetic transponder system and the gating belt system during treatment. A linear curve was fitted for all data sets and correlation factors were evaluated between the 4D electromagnetic transponder system and the gating belt system data. The 4D CT study demonstrated a modest correlation between the external marker and the pancreatic motion with R-square values larger than 0.8 for the inferior-superior (inf-sup). Then, the relative pressure from the belt gating system correlated well with the 4D electromagnetic transponder system's motion in the anterior-posterior (ant-post) and the inf-post directions. These directions have a correlation value of -0.93 and 0.76, while the lateral only had a 0.03 correlation coefficient. Based on our limited study, external surrogates can be used as predictors of the pancreatic motion in the inf-sup and the ant-post directions. Although there is a low correlation on the lateral direction, its motion is significantly shorter. In conclusion, an appropriate treatment delivery can be used for pancreatic cancer when an internal tracking system, such as the 4D electromagnetic transponder system, is unavailable.

  14. Active origami by 4D printing

    NASA Astrophysics Data System (ADS)

    Ge, Qi; Dunn, Conner K.; Qi, H. Jerry; Dunn, Martin L.

    2014-09-01

    Recent advances in three dimensional (3D) printing technology that allow multiple materials to be printed within each layer enable the creation of materials and components with precisely controlled heterogeneous microstructures. In addition, active materials, such as shape memory polymers, can be printed to create an active microstructure within a solid. These active materials can subsequently be activated in a controlled manner to change the shape or configuration of the solid in response to an environmental stimulus. This has been termed 4D printing, with the 4th dimension being the time-dependent shape change after the printing. In this paper, we advance the 4D printing concept to the design and fabrication of active origami, where a flat sheet automatically folds into a complicated 3D component. Here we print active composites with shape memory polymer fibers precisely printed in an elastomeric matrix and use them as intelligent active hinges to enable origami folding patterns. We develop a theoretical model to provide guidance in selecting design parameters such as fiber dimensions, hinge length, and programming strains and temperature. Using the model, we design and fabricate several active origami components that assemble from flat polymer sheets, including a box, a pyramid, and two origami airplanes. In addition, we directly print a 3D box with active composite hinges and program it to assume a temporary flat shape that subsequently recovers to the 3D box shape on demand.

  15. Robust statistical reconstruction for charged particle tomography

    DOEpatents

    Schultz, Larry Joe; Klimenko, Alexei Vasilievich; Fraser, Andrew Mcleod; Morris, Christopher; Orum, John Christopher; Borozdin, Konstantin N; Sossong, Michael James; Hengartner, Nicolas W

    2013-10-08

    Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.

  16. Advances in 4D radiation therapy for managing respiration: part II - 4D treatment planning.

    PubMed

    Rosu, Mihaela; Hugo, Geoffrey D

    2012-12-01

    The development of 4D CT imaging technology made possible the creation of patient models that are reflective of respiration-induced anatomical changes by adding a temporal dimension to the conventional 3D, spatial-only, patient description. This had opened a new venue for treatment planning and radiation delivery, aimed at creating a comprehensive 4D radiation therapy process for moving targets. Unlike other breathing motion compensation strategies (e.g. breath-hold and gating techniques), 4D radiotherapy assumes treatment delivery over the entire respiratory cycle - an added bonus for both patient comfort and treatment time efficiency. The time-dependent positional and volumetric information holds the promise for optimal, highly conformal, radiotherapy for targets experiencing movements caused by respiration, with potentially elevated dose prescriptions and therefore higher cure rates, while avoiding the uninvolved nearby structures. In this paper, the current state of the 4D treatment planning is reviewed, from theory to the established practical routine. While the fundamental principles of 4D radiotherapy are well defined, the development of a complete, robust and clinically feasible process still remains a challenge, imposed by limitations in the available treatment planning and radiation delivery systems.

  17. Advances in 4D Radiation Therapy for Managing Respiration: Part II – 4D Treatment Planning

    PubMed Central

    Rosu, Mihaela; Hugo, Geoffrey D.

    2014-01-01

    The development of 4D CT imaging technology made possible the creation of patient models that are reflective of respiration-induced anatomical changes by adding a temporal dimension to the conventional 3D, spatial-only, patient description. This had opened a new venue for treatment planning and radiation delivery, aimed at creating a comprehensive 4D radiation therapy process for moving targets. Unlike other breathing motion compensation strategies (e.g. breath-hold and gating techniques), 4D radiotherapy assumes treatment delivery over the entire respiratory cycle – an added bonus for both patient comfort and treatment time efficiency. The time-dependent positional and volumetric information holds the promise for optimal, highly conformal, radiotherapy for targets experiencing movements caused by respiration, with potentially elevated dose prescriptions and therefore higher cure rates, while avoiding the uninvolved nearby structures. In this paper, the current state of the 4D treatment planning is reviewed, from theory to the established practical routine. While the fundamental principles of 4D radiotherapy are well defined, the development of a complete, robust and clinically feasible process still remains a challenge, imposed by limitations in the available treatment planning and radiation delivery systems. PMID:22796324

  18. ICT4D: A Computer Science Perspective

    NASA Astrophysics Data System (ADS)

    Sutinen, Erkki; Tedre, Matti

    The term ICT4D refers to the opportunities of Information and Communication Technology (ICT) as an agent of development. Research in that field is often focused on evaluating the feasibility of existing technologies, mostly of Western or Far East Asian origin, in the context of developing regions. A computer science perspective is complementary to that agenda. The computer science perspective focuses on exploring the resources, or inputs, of a particular context and on basing the design of a technical intervention on the available resources, so that the output makes a difference in the development context. The modus operandi of computer science, construction, interacts with evaluation and exploration practices. An analysis of a contextualized information technology curriculum of Tumaini University in southern Tanzania shows the potential of the computer science perspective for designing meaningful information and communication technology for a developing region.

  19. 4D Clinical Imaging for Dynamic CAD

    PubMed Central

    McIntyre, Frederick

    2013-01-01

    A basic 4D imaging system to capture the jaw motion has been developed that produces high resolution 3D surface data. Fluorescent microspheres are brushed onto the areas of the upper and the lower arches to be imaged, producing a high-contrast random optical pattern. A hand-held imaging device operated at about 10 cm from the mouth captures time-based perspective images of the fluorescent areas. Each set of images, containing both upper and the lower arch data, is converted to a 3d point mesh using photogrammetry, thereby providing an instantaneous relative jaw position. Eight 3d positions per second are captured. Using one of the 3d frames as a reference, incremental transforms are derived to express the free body motion of the mandible. Conventional 3d models of the dentition are directly registered to the reference frame, allowing them to be animated using the derived transforms. PMID:24082882

  20. Resolution enhancement of lung 4D-CT data using multiscale interphase iterative nonlocal means

    SciTech Connect

    Zhang Yu; Yap, Pew-Thian; Wu Guorong; Feng Qianjin; Chen Wufan; Lian Jun; Shen Dinggang

    2013-05-15

    Purpose: Four-dimensional computer tomography (4D-CT) has been widely used in lung cancer radiotherapy due to its capability in providing important tumor motion information. However, the prolonged scanning duration required by 4D-CT causes considerable increase in radiation dose. To minimize the radiation-related health risk, radiation dose is often reduced at the expense of interslice spatial resolution. However, inadequate resolution in 4D-CT causes artifacts and increases uncertainty in tumor localization, which eventually results in extra damages of healthy tissues during radiotherapy. In this paper, the authors propose a novel postprocessing algorithm to enhance the resolution of lung 4D-CT data. Methods: The authors' premise is that anatomical information missing in one phase can be recovered from the complementary information embedded in other phases. The authors employ a patch-based mechanism to propagate information across phases for the reconstruction of intermediate slices in the longitudinal direction, where resolution is normally the lowest. Specifically, the structurally matching and spatially nearby patches are combined for reconstruction of each patch. For greater sensitivity to anatomical details, the authors employ a quad-tree technique to adaptively partition the image for more fine-grained refinement. The authors further devise an iterative strategy for significant enhancement of anatomical details. Results: The authors evaluated their algorithm using a publicly available lung data that consist of 10 4D-CT cases. The authors' algorithm gives very promising results with significantly enhanced image structures and much less artifacts. Quantitative analysis shows that the authors' algorithm increases peak signal-to-noise ratio by 3-4 dB and the structural similarity index by 3%-5% when compared with the standard interpolation-based algorithms. Conclusions: The authors have developed a new algorithm to improve the resolution of 4D-CT. It outperforms

  1. Four-dimensional (4D) tracking of high-temperature microparticles

    NASA Astrophysics Data System (ADS)

    Wang, Zhehui; Liu, Q.; Waganaar, W.; Fontanese, J.; James, D.; Munsat, T.

    2016-11-01

    High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation.

  2. Opening the Black Box of ICT4D: Advancing Our Understanding of ICT4D Partnerships

    ERIC Educational Resources Information Center

    Park, Sung Jin

    2013-01-01

    The term, Information and Communication Technologies for Development (ICT4D), pertains to programs or projects that strategically use ICTs (e.g. mobile phones, computers, and the internet) as a means toward the socio-economic betterment for the poor in developing contexts. Gaining the political and financial support of the international community…

  3. Time-of-flight PET image reconstruction using origin ensembles.

    PubMed

    Wülker, Christian; Sitek, Arkadiusz; Prevrhal, Sven

    2015-03-01

    The origin ensemble (OE) algorithm is a novel statistical method for minimum-mean-square-error (MMSE) reconstruction of emission tomography data. This method allows one to perform reconstruction entirely in the image domain, i.e. without the use of forward and backprojection operations. We have investigated the OE algorithm in the context of list-mode (LM) time-of-flight (TOF) PET reconstruction. In this paper, we provide a general introduction to MMSE reconstruction, and a statistically rigorous derivation of the OE algorithm. We show how to efficiently incorporate TOF information into the reconstruction process, and how to correct for random coincidences and scattered events. To examine the feasibility of LM-TOF MMSE reconstruction with the OE algorithm, we applied MMSE-OE and standard maximum-likelihood expectation-maximization (ML-EM) reconstruction to LM-TOF phantom data with a count number typically registered in clinical PET examinations. We analyzed the convergence behavior of the OE algorithm, and compared reconstruction time and image quality to that of the EM algorithm. In summary, during the reconstruction process, MMSE-OE contrast recovery (CRV) remained approximately the same, while background variability (BV) gradually decreased with an increasing number of OE iterations. The final MMSE-OE images exhibited lower BV and a slightly lower CRV than the corresponding ML-EM images. The reconstruction time of the OE algorithm was approximately 1.3 times longer. At the same time, the OE algorithm can inherently provide a comprehensive statistical characterization of the acquired data. This characterization can be utilized for further data processing, e.g. in kinetic analysis and image registration, making the OE algorithm a promising approach in a variety of applications.

  4. 4D motion animation of coronary arteries from rotational angiography

    NASA Astrophysics Data System (ADS)

    Holub, Wolfgang; Rohkohl, Christopher; Schuldhaus, Dominik; Prümmer, Marcus; Lauritsch, Günter; Hornegger, Joachim

    2011-03-01

    Time-resolved 3-D imaging of the heart is a major research topic in the medical imaging community. Recent advances in the interventional cardiac 3-D imaging from rotational angiography (C-arm CT) are now also making 4-D imaging feasible during procedures in the catheter laboratory. State-of-the-art reconstruction algorithms try to estimate the cardiac motion and utilize the motion field to enhance the reconstruction of a stable cardiac phase (diastole). The available data offers a handful of opportunities during interventional procedures, e.g. the ECG-synchronized dynamic roadmapping or the computation and analysis of functional parameters. In this paper we will demonstrate that the motion vector field (MVF) that is output by motion compensated image reconstruction algorithms is in general not directly usable for animation and motion analysis. Dependent on the algorithm different defects are investigated. A primary issue is that the MVF needs to be inverted, i.e. the wrong direction of motion is provided. A second major issue is the non-periodicity of cardiac motion. In algorithms which compute a non-periodic motion field from a single rotation the in depth motion information along viewing direction is missing, since this cannot be measured in the projections. As a result, while the MVF improves reconstruction quality, it is insufficient for motion animation and analysis. We propose an algorithm to solve both problems, i.e. inversion and missing in-depth information in a unified framework. A periodic version of the MVF is approximated. The task is formulated as a linear optimization problem where a parametric smooth motion model based on B-splines is estimated from the MVF. It is shown that the problem can be solved using a sparse QR factorization within a clinical feasible time of less than one minute. In a phantom experiment using the publicly available CAVAREV platform, the average quality of a non-periodic animation could be increased by 39% by applying the

  5. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  6. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2012 CFR

    2005-04-01

    ... 17 Commodity and Securities Exchanges 3 2005-04-01 2005-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  7. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2013 CFR

    2000-04-01

    ... 17 Commodity and Securities Exchanges 3 2000-04-01 2000-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a) Each application for an order under section 304(d)...

  8. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  9. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 3 2012-04-01 2012-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  10. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  11. 76 FR 55814 - 2,4-D; Pesticide Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-09

    ... AGENCY 40 CFR Part 180 2,4-D; Pesticide Tolerances AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: This regulation establishes tolerances for residues of 2,4-D in or on teff, bran... 180.142 be amended by establishing a tolerance for residues of the herbicide 2,4-D...

  12. 17 CFR 260.4d-8 - Content.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Content. 260.4d-8 Section 260.4d-8 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) GENERAL RULES AND REGULATIONS, TRUST INDENTURE ACT OF 1939 Rules Under Section 304 § 260.4d-8 Content. (a)...

  13. Vessels as 4-D curves: global minimal 4-D paths to extract 3-D tubular surfaces and centerlines.

    PubMed

    Li, Hua; Yezzi, Anthony

    2007-09-01

    In this paper, we propose an innovative approach to the segmentation of tubular structures. This approach combines all of the benefits of minimal path techniques such as global minimizers, fast computation, and powerful incorporation of user input, while also having the capability to represent and detect vessel surfaces directly which so far has been a feature restricted to active contour and surface techniques. The key is to represent the trajectory of a tubular structure not as a 3-D curve but to go up a dimension and represent the entire structure as a 4-D curve. Then we are able to fully exploit minimal path techniques to obtain global minimizing trajectories between two user supplied endpoints in order to reconstruct tubular structures from noisy or low contrast 3-D data without the sensitivity to local minima inherent in most active surface techniques. In contrast to standard purely spatial 3-D minimal path techniques, however, we are able to represent a full tubular surface rather than just a curve which runs through its interior. Our representation also yields a natural notion of a tube's "central curve." We demonstrate and validate the utility of this approach on magnetic resonance (MR) angiography and computed tomography (CT) images of coronary arteries. PMID:17896594

  14. 4D electron microscopy: principles and applications.

    PubMed

    Flannigan, David J; Zewail, Ahmed H

    2012-10-16

    achievable with short intense pulses containing a large number of electrons, however, are limited to tens of nanometers and nanoseconds, respectively. This is because Coulomb repulsion is significant in such a pulse, and the electrons spread in space and time, thus limiting the beam coherence. It is therefore not possible to image the ultrafast elementary dynamics of complex transformations. The challenge was to retain the high spatial resolution of a conventional TEM while simultaneously enabling the temporal resolution required to visualize atomic-scale motions. In this Account, we discuss the development of four-dimensional ultrafast electron microscopy (4D UEM) and summarize techniques and applications that illustrate the power of the approach. In UEM, images are obtained either stroboscopically with coherent single-electron packets or with a single electron bunch. Coulomb repulsion is absent under the single-electron condition, thus permitting imaging, diffraction, and spectroscopy, all with high spatiotemporal resolution, the atomic scale (sub-nanometer and femtosecond). The time resolution is limited only by the laser pulse duration and energy carried by the electron packets; the CCD camera has no bearing on the temporal resolution. In the regime of single pulses of electrons, the temporal resolution of picoseconds can be attained when hundreds of electrons are in the bunch. The applications given here are selected to highlight phenomena of different length and time scales, from atomic motions during structural dynamics to phase transitions and nanomechanical oscillations. We conclude with a brief discussion of emerging methods, which include scanning ultrafast electron microscopy (S-UEM), scanning transmission ultrafast electron microscopy (ST-UEM) with convergent beams, and time-resolved imaging of biological structures at ambient conditions with environmental cells.

  15. The thin plate as a regularizer in Bayesian SPECT reconstruction

    SciTech Connect

    Lee, Soo-Jin; Gindi, G.

    1996-12-31

    The attractions of the maximum-likelihood (ML) method for SPECT reconstruction, namely accurate system and noise modelling, are tempered by its unstable nature. The variety of Bayesian MAP approaches proposed in recent years can both stabilize the reconstructions and lead to better bias and variance. Our own work used a nonquadratic prior (the weak plate) that imposed piecewise smoothness on the first derivative of the solution to achieve results superior to those obtained using a nonquadratic prior (the weak membrane) that imposed piecewise smoothness of the zeroth derivative. By relaxing the requirement of imposing spatial discontinuities and using instead a quadratic (no discontinuities) smoothing prior, algorithms become easier to analyze, solutions easier to compute, and hyperparameter calculation becomes less of a problem. In this work, we investigated whether the advantages of weak plate relative to weak membrane are retained when non-piecewise quadratic versions - the thin plate and membrane priors - are used. We used an EM-OSL (one-step-late) algorithm to compute MAP solutions with both these priors, and found that the thin plate exhibits better bias behavior than the membrane at little cost in variance. Also, both priors outperform ML-EM in terms of bias and variance if practical stopping criteria are used for ML-EM. The net conclusion is that, while quadratic smoothing priors are not as good as piecewise versions, the simple modification of the membrane model to the thin late model leads to improved reconstructions in edge regions.

  16. Volumetric limiting spatial resolution analysis of four dimensional digital subtraction angiography (4D-DSA)

    NASA Astrophysics Data System (ADS)

    Davis, Brian; Oberstar, Erick; Royalty, Kevin; Schafer, Sebastian; Strother, Charles; Mistretta, Charles

    2015-03-01

    Static C-Arm CT 3D FDK baseline reconstructions (3D-DSA) are unable to provide temporal information to radiologists. 4D-DSA provides a time series of 3D volumes implementing a constrained image, thresholded 3D-DSA, reconstruction utilizing temporal dynamics in the 2D projections. Volumetric limiting spatial resolution (VLSR) of 4DDSA is quantified and compared to a 3D-DSA reconstruction using the same 3D-DSA parameters. Investigated were the effects of varying over significant ranges the 4D-DSA parameters of 2D blurring kernel size applied to the projection and threshold applied to the 3D-DSA when generating the constraining image of a scanned phantom (SPH) and an electronic phantom (EPH). The SPH consisted of a 76 micron tungsten wire encased in a 47 mm O.D. plastic radially concentric thin walled support structure. An 8-second/248-frame/198° scan protocol acquired the raw projection data. VLSR was determined from averaged MTF curves generated from each 2D transverse slice of every (248) 4D temporal frame (3D). 4D results for SPH and EPH were compared to the 3D-DSA. Analysis of the 3D-DSA resulted in a VLSR of 2.28 and 1.69 lp/mm for the EPH and SPH respectively. Kernel (2D) sizes of either 10x10 or 20x20 pixels with a threshold of 10% of the 3D-DSA as a constraining image provided 4D-DSA VLSR nearest to the 3D-DSA. 4D-DSA algorithms yielded 2.21 and 1.67 lp/mm with a percent error of 3.1% and 1.2% for the EPH and SPH respectively as compared to the 3D-DSA. This research indicates 4D-DSA is capable of retaining the resolution of the 3D-DSA.

  17. Motion4D-library extended

    NASA Astrophysics Data System (ADS)

    Müller, Thomas

    2011-06-01

    The new version of the Motion4D-library now also includes the integration of a Sachs basis and the Jacobi equation to determine gravitational lensing of pointlike sources for arbitrary spacetimes.New version program summaryProgram title: Motion4D-libraryCatalogue identifier: AEEX_v3_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEX_v3_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 219 441No. of bytes in distributed program, including test data, etc.: 6 968 223Distribution format: tar.gzProgramming language: C++Computer: All platforms with a C++ compilerOperating system: Linux, WindowsRAM: 61 MbytesClassification: 1.5External routines: Gnu Scientic Library (GSL) (http://www.gnu.org/software/gsl/)Catalogue identifier of previous version: AEEX_v2_0Journal reference of previous version: Comput. Phys. Comm. 181 (2010) 703Does the new version supersede the previous version?: YesNature of problem: Solve geodesic equation, parallel and Fermi-Walker transport in four-dimensional Lorentzian spacetimes. Determine gravitational lensing by integration of Jacobi equation and parallel transport of Sachs basis.Solution method: Integration of ordinary differential equations.Reasons for new version: The main novelty of the current version is the extension to integrate the Jacobi equation and the parallel transport of the Sachs basis along null geodesics. In combination, the change of the cross section of a light bundle and thus the gravitational lensing effect of a spacetime can be determined. Furthermore, we have implemented several new metrics.Summary of revisions: The main novelty of the current version is the integration of the Jacobi equation and the parallel transport of the Sachs basis along null geodesics. The corresponding set of equations readd2xμdλ2=-Γρ

  18. TH-E-17A-04: Geometric Validation of K-Space Self-Gated 4D-MRI Vs. 4D-CT Using A Respiratory Motion Phantom

    SciTech Connect

    Yue, Y; Fan, Z; Yang, W; Pang, J; McKenzie, E; Deng, Z; Tuli, R; Sandler, H; Li, D; Fraass, B

    2014-06-15

    Purpose: 4D-CT is often limited by motion artifacts, low temporal resolution, and poor phase-based target definition. We recently developed a novel k-space self-gated 4D-MRI technique with high spatial and temporal resolution. The goal here is to geometrically validate 4D-MRI using a MRI-CT compatible respiratory motion phantom and comparison to 4D-CT. Methods: 4D-MRI was acquired using 3T spoiled gradient echo-based 3D projection sequences. Respiratory phases were resolved using self-gated k-space lines as the motion surrogate. Images were reconstructed into 10 temporal bins with 1.56×1.56×1.56mm3. A MRI-CT compatible phantom was designed with a 23mm diameter ball target filled with highconcentration gadolinium(Gd) gel embedded in a 35×40×63mm3 plastic box stabilized with low-concentration Gd gel. The whole phantom was driven by an air pump. Human respiratory motion was mimicked using the controller from a commercial dynamic phantom (RSD). Four breathing settings (rates/depths: 10s/20mm, 6s/15mm, 4s/10mm, 3s/7mm) were scanned with 4D-MRI and 4D-CT (slice thickness 1.25mm). Motion ground-truth was obtained from input signals and real-time video recordings. Reconstructed images were imported into Eclipse(Varian) for target contouring. Volumes and target positions were compared with ground-truth. Initial human study was investigated on a liver patient. Results: 4D-MRI and 4D-CT scans for the different breathing cycles were reconstructed with 10 phases. Target volume in each phase was measured for both 4D-CT and 4D-MRI. Volume percentage difference for the 6.37ml target ranged from 6.67±5.33 to 11.63±5.57 for 4D-CT and from 1.47±0.52 to 2.12±1.60 for 4D-MRI. The Mann-Whitney U-test shows the 4D-MRI is significantly superior to 4D-CT (p=0.021) for phase-based target definition. Centroid motion error ranges were 1.35–1.25mm (4D-CT), and 0.31–0.12mm (4D-MRI). Conclusion: The k-space self-gated 4D-MRI we recently developed can accurately determine phase

  19. The 4D-TECS integration for NASA TSRV airplane

    NASA Technical Reports Server (NTRS)

    Kaminer, I.; Oshaughnessy, P. R.

    1989-01-01

    The integration of the Total Energy Control System (TECS) concept with 4D navigation is described. This integration was made to increase the operational capacity of modern aircraft and encourage incorporation of this increased capability with the evolving National Airspace System (NAS). Described herein is: 4D smoothing, the basic concepts of TECS, the spoiler integration concept, an algorithm for nulling out time error, speed and altitude profile modes, manual spoiler implementation, 4D logic, and the results of linear and nonlinear analysis.

  20. Killing Weeds with 2,4-D. Extension Bulletin 389.

    ERIC Educational Resources Information Center

    Lee, Oliver C.

    Discussed is the use of the herbicide 2,4-D. Though written for farmers and agricultural workers, the pamphlet considers turf weed control and use of 2,4-D near ornamental plants. Aspects of the use of this herbicide covered are: (1) the common forms of 2,4-D; (2) plant responses and tolerances to the herbicide; (3) dilution and concentration of…

  1. Pros and cons for C4d as a biomarker.

    PubMed

    Cohen, Danielle; Colvin, Robert B; Daha, Mohamed R; Drachenberg, Cinthia B; Haas, Mark; Nickeleit, Volker; Salmon, Jane E; Sis, Banu; Zhao, Ming-Hui; Bruijn, Jan A; Bajema, Ingeborg M

    2012-04-01

    The introduction of C4d in daily clinical practice in the late nineties aroused an ever-increasing interest in the role of antibody-mediated mechanisms in allograft rejection. As a marker of classical complement activation, C4d made it possible to visualize the direct link between anti-donor antibodies and tissue injury at sites of antibody binding in a graft. With the expanding use of C4d worldwide several limitations of C4d were identified. For instance, in ABO-incompatible transplantations C4d is present in the majority of grafts but this seems to point at 'graft accommodation' rather than antibody-mediated rejection. C4d is now increasingly recognized as a potential biomarker in other fields where antibodies can cause tissue damage, such as systemic autoimmune diseases and pregnancy. In all these fields, C4d holds promise to detect patients at risk for the consequences of antibody-mediated disease. Moreover, the emergence of new therapeutics that block complement activation makes C4d a marker with potential to identify patients who may possibly benefit from these drugs. This review provides an overview of the past, present, and future perspectives of C4d as a biomarker, focusing on its use in solid organ transplantation and discussing its possible new roles in autoimmunity and pregnancy. PMID:22297669

  2. Phosphodiesterase 4D Inhibitors Limit Prostate Cancer Growth Potential

    PubMed Central

    Powers, Ginny L.; Hammer, Kimberly D.P.; Domenech, Maribella; Frantskevich, Katsiaryna; Malinowski, Rita L.; Bushman, Wade; Beebe, David J.; Marker, Paul C.

    2014-01-01

    Phosphodiesterase 4D (PDE4D) has recently been implicated as a proliferation-promoting factor in prostate cancer and is over-expressed in human prostate carcinoma. However, the effects of PDE4D inhibition using pharmacological inhibitors have not been examined in prostate cancer. These studies examined the effects of selective PDE4D inhibitors, NVP-ABE171 and cilomilast, as anti-prostate cancer therapies in both in vitro and in vivo models. The effects of PDE4D inhibitors on pathways that are critical in prostate cancer and/or downstream of cyclic AMP (cAMP) were examined. Both NVP-ABE171 and cilomilast decreased cell growth. In vitro, PDE4D inhibitors lead to decreased signaling of the sonic hedgehog (SHH), Androgen Receptor (AR), and MAPK pathways, but growth inhibition was best correlated to the sonic hedgehog pathway. PDE4D inhibition also reduced proliferation of epithelial cells induced by paracrine signaling from co-cultured stromal cells that had activated hedgehog signaling. In addition, PDE4D inhibitors decreased the weight of the prostate in wild-type mice. Prostate cancer xenografts grown in nude mice that were treated with cilomilast or NVP-ABE171 had decreased wet weight and increased apoptosis compared to vehicle treated controls. These studies suggest the pharmacological inhibition of PDE4D using small molecule inhibitors is an effective option for prostate cancer therapy. Implications PDE4D inhibitors decrease the growth of prostate cancer cells in vivo and in vitro, and PDE4D inhibition has therapeutic potential in prostate cancer. PMID:25149359

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

    NASA Astrophysics Data System (ADS)

    Mory, Cyril; Janssens, Guillaume; Rit, Simon

    2016-09-01

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

  4. SU-E-J-148: Tools for Development of 4D Proton CT

    SciTech Connect

    Dou, T; Ramos-Mendez, J; Piersimoni, P; Giacometti, V; Penfold, S; Censor, Y; Faddegon, B; Low, D; Schulte, R

    2015-06-15

    Purpose: To develop tools for performing 4D proton computed tomography (CT). Methods: A suitable patient with a tumor in the right lower lobe was selected from a set of 4D CT scans. The volumetric CT images formed the basis for calculating the parameters of a breathing model that allows reconstruction of a static reference CT and CT images in each breathing phase. The images were imported into the TOPAS Monte Carlo simulation platform for simulating an experimental proton CT scan with 45 projections spaced by 4 degree intervals. Each projection acquired data for 2 seconds followed by a gantry rotation for 2 seconds without acquisition. The scan covered 180 degrees with individual protons passing through a 9-cm slab of the patient’s lung covering the moving tumor. An initial proton energy sufficient for penetrating the patient from all directions was determined. Performing the proton CT simulation, TOPAS provided output of the proton energy and coordinates registered in two planes before and after the patient, respectively. The set of projection data was then used with an iterative reconstruction algorithm to generate a volumetric proton CT image set of the static reference image and the image obtained under breathing motion, respectively. Results: An initial proton energy of 230 MeV was found to be sufficient, while for an initial energy of 200 MeV a substantial number of protons did not penetrate the patient. The reconstruction of the static reference image set provided sufficient detail for treatment planning. Conclusion: We have developed tools to perform studies of proton CT in the presence of lung motion based on the TOPAS simulation toolkit. This will allow to optimize 4D reconstruction algorithms by synchronizing the acquired proton CT data with a breathing signal and utilizing a breathing model obtained prior to the proton CT scan. This research has been supported by the National Institute Of Biomedical Imaging And Bioengineering of the National

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

    NASA Astrophysics Data System (ADS)

    Mory, Cyril; Janssens, Guillaume; Rit, Simon

    2016-09-01

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

  6. 4D Printing with Mechanically Robust, Thermally Actuating Hydrogels.

    PubMed

    Bakarich, Shannon E; Gorkin, Robert; in het Panhuis, Marc; Spinks, Geoffrey M

    2015-06-01

    A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials. PMID:25864515

  7. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed...

  8. 4D Printing with Mechanically Robust, Thermally Actuating Hydrogels.

    PubMed

    Bakarich, Shannon E; Gorkin, Robert; in het Panhuis, Marc; Spinks, Geoffrey M

    2015-06-01

    A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials.

  9. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed...

  10. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed...

  11. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed...

  12. 32 CFR 1645.4 - Exclusion from Class 4-D.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MINISTERS OF RELIGION § 1645.4 Exclusion from Class 4-D. A registrant is excluded from Class 4-D when his... duly ordained minister of religion in accordance with the ceremonial rite or discipline of a church... principles of religion and administer the ordinances of public worship, as embodied in the creed...

  13. Enhanced 4D cone-beam CT with inter-phase motion model.

    PubMed

    Li, Tianfang; Koong, Albert; Xing, Lei

    2007-09-01

    Four-dimensional (4D) cone-beam CT (CBCT) is commonly obtained by respiratory phase binning of the projections, followed by independent reconstructions of the rebinned data in each phase bin. Due to the significantly reduced number of projections per reconstruction, the quality of the 4DCBCT images is often degraded by view-aliasing artifacts easily seen in the axial view. Acquisitions using multiple gantry rotations or slow gantry rotation can increase the number of projections and substantially improve the 4D images. However, the extra cost of the scan time may set fundamental limits to their applications in clinics. Improving the trade-off between image quality and scan time is the key to making 4D onboard imaging practical and more useful. In this article, we present a novel technique toward high-quality 4DCBCT imaging without prolonging the acquisition time, referred to as the "enhanced 4DCBCT". The method correlates the data in different phase bins and integrates the internal motion into the 4DCBCT image formulation. Several strategies of the motion derivation are discussed, and the resultant images are assessed with numerical simulations as well as a clinical case.

  14. Feasibility of reduced-dose 3D/4D-DSA using a weighted edge preserving filter

    NASA Astrophysics Data System (ADS)

    Oberstar, Erick L.; Speidel, Michael A.; Davis, Brian J.; Strother, Charles; Mistretta, Charles

    2016-03-01

    A conventional 3D/4D digital subtraction angiogram (DSA) requires two rotational acquisitions (mask and fill) to compute the log-subtracted projections that are used to reconstruct a 3D/4D volume. Since all of the vascular information is contained in the fill acquisition, it is hypothesized that it is possible to reduce the x-ray dose of the mask acquisition substantially and still obtain subtracted projections adequate to reconstruct a 3D/4D volume with noise level comparable to a full dose acquisition. A full dose mask and fill acquisition were acquired from a clinical study to provide a known full dose reference reconstruction. Gaussian noise was added to the mask acquisition to simulate a mask acquisition acquired at 10% relative dose. Noise in the low-dose mask projections was reduced with a weighted edge preserving (WEP) filter designed to preserve bony edges while suppressing noise. 2D log-subtracted projections were computed from the filtered low-dose mask and full-dose fill projections, and then 3D/4D-DSA reconstruction algorithms were applied. Additional bilateral filtering was applied to the 3D volumes. The signal-to-noise ratio measured in the filtered 3D/4D-DSA volumes was compared to the full dose case. The average ratio of filtered low-dose SNR to full-dose SNR was 1.07 for the 3D-DSA and 1.05 for the 4D-DSA, indicating the method is a feasible approach to restoring SNR in DSA scans acquired with a low-dose mask. The method was also tested in a phantom study with full dose fill and 22% dose mask.

  15. Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring.

    PubMed

    Tian, Y; Stützer, K; Enghardt, W; Priegnitz, M; Helmbrecht, S; Bert, C; Fiedler, F

    2016-01-21

    Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with ⩽ 4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed.

  16. Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Stützer, K.; Enghardt, W.; Priegnitz, M.; Helmbrecht, S.; Bert, C.; Fiedler, F.

    2016-01-01

    Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with  ⩽4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed.

  17. Experimental investigation of irregular motion impact on 4D PET-based particle therapy monitoring.

    PubMed

    Tian, Y; Stützer, K; Enghardt, W; Priegnitz, M; Helmbrecht, S; Bert, C; Fiedler, F

    2016-01-21

    Particle therapy positron emission tomography (PT-PET) is an in vivo and non-invasive imaging technique to monitor treatment delivery in particle therapy. The inevitable patient respiratory motion during irradiation causes artefacts and inaccurate activity distribution in PET images. Four-dimensional (4D) maximum likelihood expectation maximisation (4D MLEM) allows for a compensation of these effects, but has up to now been restricted to regular motion for PT-PET investigations. However, intra-fractional motion during treatment might differ from that during acquisition of the 4D-planning CT (e.g. amplitude variation, baseline drift) and therefore might induce inaccurate 4D PET reconstruction results. This study investigates the impact of different irregular analytical one-dimensional (1D) motion patterns on PT-PET imaging by means of experiments with a radioactive source and irradiated moving phantoms. Three sorting methods, namely phase sorting, equal amplitude sorting and event-based amplitude sorting, were applied to manage the PET list-mode data. The influence of these sorting methods on the motion compensating algorithm has been analysed. The event-based amplitude sorting showed a superior performance and it is applicable for irregular motions with ⩽ 4 mm amplitude elongation and drift. For motion with 10 mm baseline drift, the normalised root mean square error was as high as 10.5% and a 10 mm range deviation was observed. PMID:26733104

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  19. Cardiac C-arm CT: 4D non-model based heart motion estimation and its application

    NASA Astrophysics Data System (ADS)

    Prümmer, M.; Fahrig, R.; Wigström, L.; Boese, J.; Lauritsch, G.; Strobel, N.; Hornegger, J.

    2007-03-01

    The combination of real-time fluoroscopy and 3D cardiac imaging on the same C-arm system is a promising technique that might improve therapy planning, guiding, and monitoring in the interventional suite. In principal, to reconstruct a 3D image of the beating heart at a particular cardiac phase, a complete set of X-ray projection data representing that phase is required. One approximate approach is the retrospectively ECG-gated FDK reconstruction (RG-FDK). From the acquired data set of N s multiple C-arm sweeps, those projection images which are acquired closest in time to the desired cardiac phase are retrospectively selected. However, this approach uses only 1/ N s of the obtained data. Our goal is to utilize data from other cardiac phases as well. In order to minimize blurring and motion artifacts, cardiac motion has to be compensated for, which can be achieved using a temporally dependent spatial 3D warping of the filtered-backprojections. In this work we investigate the computation of the 4D heart motion based on prior reconstructions of several cardiac phases using RG-FDK. A 4D motion estimation framework is presented using standard fast non-rigid registration. A smooth 4D motion vector field (MVF) represents the relative deformation compared to a reference cardiac phase. A 4D deformation regridding by adaptive supersampling allows selecting any reference phase independently of the set of phases used in the RG-FDK for a motion corrected reconstruction. Initial promising results from in vivo experiments are shown. The subjects individual 4D cardiac MVF could be computed from only three RG-FDK image volumes. In addition, all acquired projection data were motion corrected and subsequently used for image reconstruction to improve the signal-to-noise ratio compared to RG-FDK.

  20. 4D-fingerprints, universal QSAR and QSPR descriptors.

    PubMed

    Senese, Craig L; Duca, J; Pan, D; Hopfinger, A J; Tseng, Y J

    2004-01-01

    An elusive goal in the field of chemoinformatics and molecular modeling has been the generation of a set of descriptors that, once calculated for a molecule, may be used in a wide variety of applications. Since such universal descriptors are generated free from external constraints, they are inherently independent of the data set in which they are employed. The realization of a set of universal descriptors would significantly streamline such chemoinformatics tasks as virtual high-throughout screening (VHTS) and toxicity profiling. The current study reports the derivation and validation of a potential set of universal descriptors, referred to as the 4D-fingerprints. The 4D-fingerprints are derived from the 4D-molecular similarity analysis. To evaluate the applicability of the 4D-fingerprints as universal descriptors, they are used to generate descriptive QSAR models for 5 independent training sets. Each of the training sets has been analyzed previously by several varying QSAR methods, and the results of the models generated using the 4D-fingerprints are compared to the results of the previous QSAR analyses. It was found that the models generated using the 4D-fingerprints are comparable in quality, based on statistical measures of fit and test set prediction, to the previously reported models for the other QSAR methods. This finding is particularly significant considering the 4D-fingerprints are generated independent of external constraints such as alignment, while the QSAR methods used for comparison all require an alignment analysis.

  1. 4D micro-CT-based perfusion imaging in small animals

    NASA Astrophysics Data System (ADS)

    Badea, C. T.; Johnston, S. M.; Lin, M.; Hedlund, L. W.; Johnson, G. A.

    2009-02-01

    Quantitative in-vivo imaging of lung perfusion in rodents can provide critical information for preclinical studies. However, the combined challenges of high temporal and spatial resolution have made routine quantitative perfusion imaging difficult in rodents. We have recently developed a dual tube/detector micro-CT scanner that is well suited to capture first-pass kinetics of a bolus of contrast agent used to compute perfusion information. Our approach is based on the paradigm that the same time density curves can be reproduced in a number of consecutive, small (i.e. 50μL) injections of iodinated contrast agent at a series of different angles. This reproducibility is ensured by the high-level integration of the imaging components of our system, with a micro-injector, a mechanical ventilator, and monitoring applications. Sampling is controlled through a biological pulse sequence implemented in LabVIEW. Image reconstruction is based on a simultaneous algebraic reconstruction technique implemented on a GPU. The capabilities of 4D micro-CT imaging are demonstrated in studies on lung perfusion in rats. We report 4D micro-CT imaging in the rat lung with a heartbeat temporal resolution of 140 ms and reconstructed voxels of 88 μm. The approach can be readily extended to a wide range of important preclinical models, such as tumor perfusion and angiogenesis, and renal function.

  2. Predicting lower mantle heterogeneity from 4-D Earth models

    NASA Astrophysics Data System (ADS)

    Flament, Nicolas; Williams, Simon; Müller, Dietmar; Gurnis, Michael; Bower, Dan J.

    2016-04-01

    basal layer ˜ 4% denser than ambient mantle. Increasing convective vigour (Ra ≈ 5 x 108) or decreasing the density of the basal layer decreases both the accuracy and sensitivity of the predicted lower mantle structure. References: D. J. Bower, M. Gurnis, N. Flament, Assimilating lithosphere and slab history in 4-D Earth models. Phys. Earth Planet. Inter. 238, 8-22 (2015). V. Lekic, S. Cottaar, A. Dziewonski, B. Romanowicz, Cluster analysis of global lower mantle tomography: A new class of structure and implications for chemical heterogeneity. Earth Planet. Sci. Lett. 357, 68-77 (2012).

  3. 4D Visualization of Experimental Procedures in Rock Physics

    NASA Astrophysics Data System (ADS)

    Vanorio, T.; di Bonito, C.

    2010-12-01

    Engaging students in laboratory classes in geophysics is becoming more and more difficult. This is primarily because of an ever-widening gap between the less appealing aspects that characterize these courses (e.g., lengthiness of the experimental operations, high student/instrument ratio, limited time associated with lack of previous hands-on experiences, and logistical and safety concerns) and the life style of the 21st century generations (i.e., extensive practice to high-tech tools, high-speed communications and computing, 3D graphics and HD videos). To bridge the gap and enhance the teaching strategy of laboratory courses in geophysics, we have created simulator-training tools for use in preparation for the actual experimental phase. We are using a modeling, animation, and rendering package to create (a) 3D models that accurately reproduce actual scenarios and instruments used for the measurement of rock physics properties and (b) 4D interactive animations that simulate hands-on demonstrations of the experimental procedures. We present here a prototype describing step-by-step the experimental protocol and the principles behind the measurement of rock porosity. The tool reproduces an actual helium porosimeter and makes use of interactive animations, guided text, and a narrative voice guiding the audience through the different phases of the experimental process. Our strategy is to make the most of new technologies while preserving the accuracy of classical laboratory methods and practices. These simulations are not intended to replace traditional lab work; rather they provide students with the opportunity for review and repetition. The primary goal is thus to help students familiarize themselves during their earlier curricula with lab methodologies, thus minimizing apparent hesitation and frustration in later classes. This may also increase the level of interest and involvement of undergraduate students and, in turn, enhance their keenness to pursue their

  4. Semiautomatic method to identify the best phase for gated RT in lung region by 4D-PET/CT acquisitions

    SciTech Connect

    Mancosu, Pietro; Danna, Massimo; Bettinardi, Valentino; Aquilina, Mark Anthony; Lobefalo, Francesca; Cozzi, Luca; Fogliata, Antonella; Scorsetti, Marta

    2011-01-15

    Purpose: Delineating tumor motion by four-dimensional positron emission tomography/computed tomography (4D-PET/CT) is a crucial step for gated radiotherapy (RT). This article quantitatively evaluates semiautomatic algorithms for tumor shift estimation in the lung region due to patient respiration by 4D-PET/CT, in order to support the selection of the best phases for gated RT, by considering the most stable phases of the breathing cycle. Methods: Three mobile spheres and ten selected lesions were included in this study. 4D-PET/CT data were reconstructed and classified into six/ten phases. The semiautomatic algorithms required the generation of single sets of images representative of the full target motion, used as masks for segmenting the phases. For 4D-CT, a pre-established HU range was used, whereas three thresholds (100%, 80%, and 40%) were evaluated for 4D-PET. By using these segmentations, the authors estimated the lesion motion from the shifting centroids, and the phases with the least motion were also deduced including the phases with a curve slope less than 2 mm/{Delta}phase. The proposed algorithms were validated by comparing the results to those generated entirely by manual contouring. Results: In the phantom study, the mean difference between the manual contour and the semiautomatic technique was 0.1{+-}0.1 mm for 4D-CT and 0.2{+-}0.1 mm for the 4D-PET based on 40% threshold. In the patients' series, the mean difference was 0.9{+-}0.6 mm for 4D-CT and 0.8{+-}0.2 mm for the 4D-PET based on 40% threshold. Conclusions: Estimation of lesion motion by the proposed semiautomatic algorithm can be used to evaluate tumor motion due to breathing.

  5. Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT

    NASA Astrophysics Data System (ADS)

    Lee, Taek-Soo; Frey, Eric C.; Tsui, Benjamin M. W.

    2015-04-01

    This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical observer model extends the conventional channelized Hotelling observer (CHO) based on a set of 2D spatial channels and the second is a proposed model that uses a set of 4D space-time channels. Simulated projection data were generated using the 4D NURBS-based cardiac-torso (NCAT) phantom with 16 gates/cardiac cycle. The activity distribution modelled uptake of 99mTc MIBI with normal perfusion and a regional wall motion defect. An analytical projector was used in the simulation and the filtered backprojection (FBP) algorithm was used in image reconstruction followed by spatial and temporal low-pass filtering with various cut-off frequencies. Then, we extracted 2D image slices from each time frame and reorganized them into a set of cine images. For the first model, we applied 2D spatial channels to the cine images and generated a set of feature vectors that were stacked for the images from different slices of the heart. The process was repeated for each of the 1,024 noise realizations, and CHO and receiver operating characteristics (ROC) analysis methodologies were applied to the ensemble of the feature vectors to compute areas under the ROC curves (AUCs). For the second model, a set of 4D space-time channels was developed and applied to the sets of cine images to produce space-time feature vectors to which the CHO methodology was applied. The AUC values of the second model showed better agreement (Spearman’s rank correlation (SRC) coefficient = 0.8) to human observer results than those from the first model (SRC coefficient = 0.4). The agreement with human observers indicates the proposed 4D mathematical observer model provides a good predictor of the

  6. Development of 4D mathematical observer models for the task-based evaluation of gated myocardial perfusion SPECT.

    PubMed

    Lee, Taek-Soo; Frey, Eric C; Tsui, Benjamin M W

    2015-04-01

    This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical observer model extends the conventional channelized Hotelling observer (CHO) based on a set of 2D spatial channels and the second is a proposed model that uses a set of 4D space-time channels. Simulated projection data were generated using the 4D NURBS-based cardiac-torso (NCAT) phantom with 16 gates/cardiac cycle. The activity distribution modelled uptake of (99m)Tc MIBI with normal perfusion and a regional wall motion defect. An analytical projector was used in the simulation and the filtered backprojection (FBP) algorithm was used in image reconstruction followed by spatial and temporal low-pass filtering with various cut-off frequencies. Then, we extracted 2D image slices from each time frame and reorganized them into a set of cine images. For the first model, we applied 2D spatial channels to the cine images and generated a set of feature vectors that were stacked for the images from different slices of the heart. The process was repeated for each of the 1,024 noise realizations, and CHO and receiver operating characteristics (ROC) analysis methodologies were applied to the ensemble of the feature vectors to compute areas under the ROC curves (AUCs). For the second model, a set of 4D space-time channels was developed and applied to the sets of cine images to produce space-time feature vectors to which the CHO methodology was applied. The AUC values of the second model showed better agreement (Spearman's rank correlation (SRC) coefficient = 0.8) to human observer results than those from the first model (SRC coefficient = 0.4). The agreement with human observers indicates the proposed 4D mathematical observer model provides a good predictor of the

  7. SU-E-J-06: A Feasibility Study On Clinical Implementation of 4D-CBCT in Lung Cancer Treatment

    SciTech Connect

    Hu, Y; Stanford, J; Duggar, W; Ruan, C; He, R; Yang, C

    2014-06-01

    Purpose: Four-dimensional cone-beam CT (4D-CBCT) is a novel imaging technique to setup patients with pulmonary lesions in radiation therapy. This paper is to perform a feasibility study on the implementation of 4D-CBCT as image guidance for (1) SBRT and (2) Low Modulation (Low-Mod) IMRT in lung cancer treatment. Methods: Image artifacts and observers variability are evaluated by analyzing the 4D-CT QA phantom and patient 4D image data. There are two 4D-CBCT image artifacts: (1) Spatial artifact caused by the patient irregular breathing pattern will generate blurring and anatomy gap/overlap; (2) Cone beam scattering and hardening artifact will affect the image spatial and contrast resolution. The couch shift varies between 1mm to 3mm from different observers during the 4D-CBCT registration. Breath training is highly recommended to improve the respiratory regularity during CT simulation and treatment, especially for SBRT. Elekta XVI 4.5 Symmetry protocol is adopted in the patient 4DCBCT scanning and intensity-based registration. Physician adjustments on the auto-registration are involved prior to the treatment. Physician peer review on 4D-CBCT image acquisition and registration is also recommended to reduce the inter-observer variability. The average 4D-CT in reference volume coordinates is exported to MIM Vista 5.6.2 to manually fuse to the planning CT for further evaluation. Results: (1) SBRT: 4DCBCT is performed in dry-run and in each treatment fraction. Image registration and couch shift are reviewed by another physician on the 1st fraction before the treatment starts. (2) Low-Mod IMRT: 4D-CBCT is performed and peer reviewed on weekly basis. Conclusion: 4D-CBCT in SBRT dry-run can discover the ITV discrepancies caused by the low quality 4D-CT simulation. 4D-CBCT during SBRT and Low-Mod IMRT treatment provides physicians more confidence to target lung tumor and capability to evaluate inter-fractional ITV changes. More advanced 4D-CBCT scan protocol and

  8. Graph-based retrospective 4D image construction from free-breathing MRI slice acquisitions

    NASA Astrophysics Data System (ADS)

    Tong, Yubing; Udupa, Jayaram K.; Ciesielski, Krzysztof C.; McDonough, Joseph M.; Mong, Andrew; Campbell, Robert M.

    2014-03-01

    4D or dynamic imaging of the thorax has many potential applications [1, 2]. CT and MRI offer sufficient speed to acquire motion information via 4D imaging. However they have different constraints and requirements. For both modalities both prospective and retrospective respiratory gating and tracking techniques have been developed [3, 4]. For pediatric imaging, x-ray radiation becomes a primary concern and MRI remains as the de facto choice. The pediatric subjects we deal with often suffer from extreme malformations of their chest wall, diaphragm, and/or spine, as such patient cooperation needed by some of the gating and tracking techniques are difficult to realize without causing patient discomfort. Moreover, we are interested in the mechanical function of their thorax in its natural form in tidal breathing. Therefore free-breathing MRI acquisition is the ideal modality of imaging for these patients. In our set up, for each coronal (or sagittal) slice position, slice images are acquired at a rate of about 200-300 ms/slice over several natural breathing cycles. This produces typically several thousands of slices which contain both the anatomic and dynamic information. However, it is not trivial to form a consistent and well defined 4D volume from these data. In this paper, we present a novel graph-based combinatorial optimization solution for constructing the best possible 4D scene from such data entirely in the digital domain. Our proposed method is purely image-based and does not need breath holding or any external surrogates or instruments to record respiratory motion or tidal volume. Both adult and children patients' data are used to illustrate the performance of the proposed method. Experimental results show that the reconstructed 4D scenes are smooth and consistent spatially and temporally, agreeing with known shape and motion of the lungs.

  9. 3D and 4D magnetic susceptibility tomography based on complex MR images

    DOEpatents

    Chen, Zikuan; Calhoun, Vince D

    2014-11-11

    Magnetic susceptibility is the physical property for T2*-weighted magnetic resonance imaging (T2*MRI). The invention relates to methods for reconstructing an internal distribution (3D map) of magnetic susceptibility values, .chi. (x,y,z), of an object, from 3D T2*MRI phase images, by using Computed Inverse Magnetic Resonance Imaging (CIMRI) tomography. The CIMRI technique solves the inverse problem of the 3D convolution by executing a 3D Total Variation (TV) regularized iterative convolution scheme, using a split Bregman iteration algorithm. The reconstruction of .chi. (x,y,z) can be designed for low-pass, band-pass, and high-pass features by using a convolution kernel that is modified from the standard dipole kernel. Multiple reconstructions can be implemented in parallel, and averaging the reconstructions can suppress noise. 4D dynamic magnetic susceptibility tomography can be implemented by reconstructing a 3D susceptibility volume from a 3D phase volume by performing 3D CIMRI magnetic susceptibility tomography at each snapshot time.

  10. Sparse-CAPR: Highly-Accelerated 4D CE-MRA with Parallel Imaging and Nonconvex Compressive Sensing

    PubMed Central

    Trzasko, Joshua D.; Haider, Clifton R.; Borisch, Eric A.; Campeau, Norbert G.; Glockner, James F.; Riederer, Stephen J.; Manduca, Armando

    2012-01-01

    CAPR is a SENSE-type parallel 3DFT acquisition paradigm for 4D contrast-enhanced magnetic resonance angiography (CE-MRA) that has been demonstrated capable of providing high spatial and temporal resolution, diagnostic-quality images at very high acceleration rates. However, CAPR images are typically reconstructed online using Tikhonov regularization and partial Fourier methods, which are prone to exhibit noise amplification and undersampling artifacts when operating at very high acceleration rates. In this work, a sparsity-driven offline reconstruction framework for CAPR is developed and demonstrated to consistently provide improvements over the currently-employed reconstruction strategy against these ill-effects. Moreover, the proposed reconstruction strategy requires no changes to the existing CAPR acquisition protocol, and an efficient numerical optimization and hardware system are described that allow for a 256×160×80 volume CE-MRA volume to be reconstructed from an 8-channel data set in less than two minutes. PMID:21608028

  11. C4d staining as immunohistochemical marker in inflammatory myopathies.

    PubMed

    Pytel, Peter

    2014-10-01

    The diagnosis of an inflammatory myopathy is often established based on basic histologic studies. Additional immunohistochemical studies are sometimes required to support the diagnosis and the classification of inflammatory myopathies. Staining for major histocompatibility complex 1 (MHC1) often shows increased sarcolemmal labeling in inflammatory myopathies. Endomysial capillary staining C5b-9 (membrane attack complex) is a feature that is reported as frequently associated with dermatomyositis. Immunohistochemical staining for C4d is widely used for various applications including the assessment of antibody-mediated rejection after solid organ transplantation. In the context of dermatomyositis, C4d staining has been described in skin biopsies but not in muscle biopsies. A total of 32 muscle biopsy specimens were examined. The hematoxylin and eosin-stained slides were reviewed, and immunohistochemical studies for MHC1, C5b-9, and C4d were conducted. The staining observed for C5b-9 and C4d was compared. Overall, the staining pattern for C4d mirrored the one observed for C5b-9 in the examined muscle biopsy specimens. There was high and statistically significant (P<0.0001) correlation between the staining seen with these 2 antibodies. Both antibodies labeled the cytoplasm of degenerating necrotic myofibers. In addition, both antibodies showed distinct endomysial capillary labeling in a subset of dermatomyositis. Areas with perifascicular atrophy often exhibited the most prominent vascular labeling for C4d and C5b-9. In conclusion, C4d and C5b-9 show similar expression patterns in muscle biopsies of patients with inflammatory myopathies and both highlight the presence of vascular labeling associated with dermatomyositis. C4d antibodies are widely used and may offer an alternative for C5b-9 staining.

  12. Substitutional 4d and 5d impurities in graphene.

    PubMed

    Alonso-Lanza, Tomás; Ayuela, Andrés; Aguilera-Granja, Faustino

    2016-08-21

    We describe the structural and electronic properties of graphene doped with substitutional impurities of 4d and 5d transition metals. The adsorption energies and distances for 4d and 5d metals in graphene show similar trends for the later groups in the periodic table, which are also well-known characteristics of 3d elements. However, along earlier groups the 4d impurities in graphene show very similar adsorption energies, distances and magnetic moments to the 5d ones, which can be related to the influence of the 4d and 5d lanthanide contraction. Surprisingly, within the manganese group, the total magnetic moment of 3 μB for manganese is reduced to 1 μB for technetium and rhenium. We find that compared with 3d elements, the larger size of the 4d and 5d elements causes a high degree of hybridization with the neighbouring carbon atoms, reducing spin splitting in the d levels. It seems that the magnetic adjustment of graphene could be significantly different if 4d or 5d impurities are used instead of 3d impurities.

  13. Substitutional 4d and 5d impurities in graphene.

    PubMed

    Alonso-Lanza, Tomás; Ayuela, Andrés; Aguilera-Granja, Faustino

    2016-08-21

    We describe the structural and electronic properties of graphene doped with substitutional impurities of 4d and 5d transition metals. The adsorption energies and distances for 4d and 5d metals in graphene show similar trends for the later groups in the periodic table, which are also well-known characteristics of 3d elements. However, along earlier groups the 4d impurities in graphene show very similar adsorption energies, distances and magnetic moments to the 5d ones, which can be related to the influence of the 4d and 5d lanthanide contraction. Surprisingly, within the manganese group, the total magnetic moment of 3 μB for manganese is reduced to 1 μB for technetium and rhenium. We find that compared with 3d elements, the larger size of the 4d and 5d elements causes a high degree of hybridization with the neighbouring carbon atoms, reducing spin splitting in the d levels. It seems that the magnetic adjustment of graphene could be significantly different if 4d or 5d impurities are used instead of 3d impurities. PMID:27439363

  14. Semaphorin 4D Promotes Skeletal Metastasis in Breast Cancer.

    PubMed

    Yang, Ying-Hua; Buhamrah, Asma; Schneider, Abraham; Lin, Yi-Ling; Zhou, Hua; Bugshan, Amr; Basile, John R

    2016-01-01

    Bone density is controlled by interactions between osteoclasts, which resorb bone, and osteoblasts, which deposit it. The semaphorins and their receptors, the plexins, originally shown to function in the immune system and to provide chemotactic cues for axon guidance, are now known to play a role in this process as well. Emerging data have identified Semaphorin 4D (Sema4D) as a product of osteoclasts acting through its receptor Plexin-B1 on osteoblasts to inhibit their function, tipping the balance of bone homeostasis in favor of resorption. Breast cancers and other epithelial malignancies overexpress Sema4D, so we theorized that tumor cells could be exploiting this pathway to establish lytic skeletal metastases. Here, we use measurements of osteoblast and osteoclast differentiation and function in vitro and a mouse model of skeletal metastasis to demonstrate that both soluble Sema4D and protein produced by the breast cancer cell line MDA-MB-231 inhibits differentiation of MC3T3 cells, an osteoblast cell line, and their ability to form mineralized tissues, while Sema4D-mediated induction of IL-8 and LIX/CXCL5, the murine homologue of IL-8, increases osteoclast numbers and activity. We also observe a decrease in the number of bone metastases in mice injected with MDA-MB-231 cells when Sema4D is silenced by RNA interference. These results are significant because treatments directed at suppression of skeletal metastases in bone-homing malignancies usually work by arresting bone remodeling, potentially leading to skeletal fragility, a significant problem in patient management. Targeting Sema4D in these cancers would not affect bone remodeling and therefore could elicit an improved therapeutic result without the debilitating side effects.

  15. Soil matrix and macropore biodegradation of 2,4-D

    SciTech Connect

    Pivetz, B.E.; Steenhuis, T.S.

    1995-07-01

    Preferential flow of pesticides in macropores can lead to decreased travel times through the vadose zone and increased groundwater contamination. Macropores, however, may present a favorable environment for biodegradation because of greater oxygen, nutrient, and substrate supply, and higher microbial populations in earthworm burrows, compared to the soil matrix. The biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was measured in macropores and soil matrix of packed soil columns (7.0-cm diam., 10-cm length) and undisturbed cores contained as well-defined artificial macropore and the undisturbed cores contained earthworm-burrow macropores. A 50 {mu}g/L 2,4-D solution was continuously applied to the unsaturated soil surface and breakthrough curves (BTCs) indicating pesticide loss in the effluent were obtained from the soil matrix and macropore flow paths. Biodegradation rates were calculated separately for each flow path by comparing the BTCs to BTCs representing abiotic conditions, and dividing the 2,4-D loss by the travel time through each flow path. The biodegradation rates increased with time in both flow paths, and the final biodegradation rate in the macropore region surpassed that of the matrix, presumably because of increased microbial populations in the macropore. Complete loss of the 2,4-D in both flow paths was observed after continuous application of 2,4-D for 400 h, with maximum column-averaged 2,4-D loss rates of 0.879 {mu}g/(L h) in the matrix and 1.073 {mu}g/(L h) in the macropore. Biodegradation of 2,4-D was also observed in the macropore and matrix regions of the undisturbed soil cores. 19 refs., 7 figs., 2 tabs.

  16. Semaphorin 4D Promotes Skeletal Metastasis in Breast Cancer

    PubMed Central

    Yang, Ying-Hua; Buhamrah, Asma; Schneider, Abraham; Lin, Yi-Ling; Zhou, Hua; Bugshan, Amr; Basile, John R.

    2016-01-01

    Bone density is controlled by interactions between osteoclasts, which resorb bone, and osteoblasts, which deposit it. The semaphorins and their receptors, the plexins, originally shown to function in the immune system and to provide chemotactic cues for axon guidance, are now known to play a role in this process as well. Emerging data have identified Semaphorin 4D (Sema4D) as a product of osteoclasts acting through its receptor Plexin-B1 on osteoblasts to inhibit their function, tipping the balance of bone homeostasis in favor of resorption. Breast cancers and other epithelial malignancies overexpress Sema4D, so we theorized that tumor cells could be exploiting this pathway to establish lytic skeletal metastases. Here, we use measurements of osteoblast and osteoclast differentiation and function in vitro and a mouse model of skeletal metastasis to demonstrate that both soluble Sema4D and protein produced by the breast cancer cell line MDA-MB-231 inhibits differentiation of MC3T3 cells, an osteoblast cell line, and their ability to form mineralized tissues, while Sema4D-mediated induction of IL-8 and LIX/CXCL5, the murine homologue of IL-8, increases osteoclast numbers and activity. We also observe a decrease in the number of bone metastases in mice injected with MDA-MB-231 cells when Sema4D is silenced by RNA interference. These results are significant because treatments directed at suppression of skeletal metastases in bone-homing malignancies usually work by arresting bone remodeling, potentially leading to skeletal fragility, a significant problem in patient management. Targeting Sema4D in these cancers would not affect bone remodeling and therefore could elicit an improved therapeutic result without the debilitating side effects. PMID:26910109

  17. Motion artifacts occurring at the lung/diaphragm interface using 4D CT attenuation correction of 4D PET scans.

    PubMed

    Killoran, Joseph H; Gerbaudo, Victor H; Mamede, Marcelo; Ionascu, Dan; Park, Sang-June; Berbeco, Ross

    2011-11-15

    For PET/CT, fast CT acquisition time can lead to errors in attenuation correction, particularly at the lung/diaphragm interface. Gated 4D PET can reduce motion artifacts, though residual artifacts may persist depending on the CT dataset used for attenuation correction. We performed phantom studies to evaluate 4D PET images of targets near a density interface using three different methods for attenuation correction: a single 3D CT (3D CTAC), an averaged 4D CT (CINE CTAC), and a fully phase matched 4D CT (4D CTAC). A phantom was designed with two density regions corresponding to diaphragm and lung. An 8 mL sphere phantom loaded with 18F-FDG was used to represent a lung tumor and background FDG included at an 8:1 ratio. Motion patterns of sin(x) and sin4(x) were used for dynamic studies. Image data was acquired using a GE Discovery DVCT-PET/CT scanner. Attenuation correction methods were compared based on normalized recovery coefficient (NRC), as well as a novel quantity "fixed activity volume" (FAV) introduced in our report. Image metrics were compared to those determined from a 3D PET scan with no motion present (3D STATIC). Values of FAV and NRC showed significant variation over the motion cycle when corrected by 3D CTAC images. 4D CTAC- and CINE CTAC-corrected PET images reduced these motion artifacts. The amount of artifact reduction is greater when the target is surrounded by lower density material and when motion was based on sin4(x). 4D CTAC reduced artifacts more than CINE CTAC for most scenarios. For a target surrounded by water equivalent material, there was no advantage to 4D CTAC over CINE CTAC when using the sin(x) motion pattern. Attenuation correction using both 4D CTAC or CINE CTAC can reduce motion artifacts in regions that include a tissue interface such as the lung/diaphragm border. 4D CTAC is more effective than CINE CTAC at reducing artifacts in some, but not all, scenarios.

  18. New C4D Sensor with a Simulated Inductor

    PubMed Central

    Lyu, Yingchao; Ji, Haifeng; Yang, Shijie; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2016-01-01

    A new capacitively coupled contactless conductivity detection (C4D) sensor with an improved simulated inductor is developed in this work. The improved simulated inductor is designed on the basis of the Riordan-type floating simulated inductor. With the improved simulated inductor, the negative influence of the coupling capacitances is overcome and the conductivity measurement is implemented by the series resonance principle. The conductivity measurement experiments are carried out in three pipes with different inner diameters of 3.0 mm, 4.6 mm and 6.4 mm, respectively. The experimental results show that the designs of the new C4D sensor and the improved simulated inductor are successful. The maximum relative error of the conductivity measurement is less than 5%. Compared with the C4D sensors using practical inductors, the measurement accuracy of the new C4D sensor is comparable. The research results also indicate that the adjustability of a simulated inductor can reduce the requirement for the AC source and guarantee the interchangeableness. Meanwhile, it is recommended that making the potential of one terminal of a simulated inductor stable is beneficial to the running stability. Furthermore, this work indirectly verifies the possibility and feasibility of the miniaturization of the C4D sensor by using the simulated inductor technique and lays a good foundation for future research work. PMID:26828493

  19. 4D rotational x-ray imaging of wrist joint dynamic motion

    SciTech Connect

    Carelsen, Bart; Bakker, Niels H.; Strackee, Simon D.; Boon, Sjirk N.; Maas, Mario; Sabczynski, Joerg; Grimbergen, Cornelis A.; Streekstra, Geert J.

    2005-09-15

    Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray modalities and sophisticated 2D to 3D matching for the complex wrist joint. We present a method for the acquisition of dynamic 3D images of a moving joint. In our method a 3D-rotational x-ray (3D-RX) system is used to image a cyclically moving joint. The cyclic motion is synchronized to the x-ray acquisition to yield multiple sets of projection images, which are reconstructed to a series of time resolved 3D images, i.e., four-dimensional rotational x ray (4D-RX). To investigate the obtained image quality parameters the full width at half maximum (FWHM) of the point spread function (PSF) via the edge spread function and the contrast to noise ratio between air and phantom were determined on reconstructions of a bullet and rod phantom, using 4D-RX as well as stationary 3D-RX images. The CNR in volume reconstructions based on 251 projection images in the static situation and on 41 and 34 projection images of a moving phantom were 6.9, 3.0, and 2.9, respectively. The average FWHM of the PSF of these same images was, respectively, 1.1, 1.7, and 2.2 mm orthogonal to the motion and parallel to direction of motion 0.6, 0.7, and 1.0 mm. The main deterioration of 4D-RX images compared to 3D-RX images is due to the low number of projection images used and not to the motion of the object. Using 41 projection images seems the best setting for the current system. Experiments on a postmortem wrist show the feasibility of the method for imaging 3D dynamic joint motion. We expect that 4D-RX will pave the way to improved assessment of joint disorders by detection of 3D dynamic motion patterns in joints.

  20. Three dimensional dose verification of VMAT plans using the Octavius 4D dosimetric system

    NASA Astrophysics Data System (ADS)

    Arumugam, Sankar; Xing, Aitang; Young, Tony; Thwaites, David; Holloway, Lois

    2015-01-01

    The Octavius 4D dosimetric system generates a 3D dose matrix based on a measured planar dose and user supplied Percentage Depth Dose (PDD) data. The accuracy of 3D dose matrices reconstructed by the Octavius 4D dosimetric system was systematically studied for an open static field, an open arc field and clinical VMAT plans. The Octavius reconstructed 3D dose matrices were compared with the Treatment Planning System (TPS) calculated 3D dose matrices using 3D gamma (γ) analysis with 2%/2mm and 3%/3mm tolerance criteria. The larger detector size in the 2D detector array of the Octavius system resulted in failed voxels in the high dose gradient regions. For the open arc fields mean (1σ) γ pass rates of 84.5(8.9) % and 94.2(4.5) % were observed with 2%/2mm and 3%/3mm tolerance criteria respectively and for clinical VMAT plans mean (1σ) γ pass rates of 86.8(3.5) % and 96.7(1.4) % were observed.

  1. The study of integration about measurable image and 4D production

    NASA Astrophysics Data System (ADS)

    Zhang, Chunsen; Hu, Pingbo; Niu, Weiyun

    2008-12-01

    In this paper, we create the geospatial data of three-dimensional (3D) modeling by the combination of digital photogrammetry and digital close-range photogrammetry. For large-scale geographical background, we make the establishment of DEM and DOM combination of three-dimensional landscape model based on the digital photogrammetry which uses aerial image data to make "4D" (DOM: Digital Orthophoto Map, DEM: Digital Elevation Model, DLG: Digital Line Graphic and DRG: Digital Raster Graphic) production. For the range of building and other artificial features which the users are interested in, we realize that the real features of the three-dimensional reconstruction adopting the method of the digital close-range photogrammetry can come true on the basis of following steps : non-metric cameras for data collection, the camera calibration, feature extraction, image matching, and other steps. At last, we combine three-dimensional background and local measurements real images of these large geographic data and realize the integration of measurable real image and the 4D production.The article discussed the way of the whole flow and technology, achieved the three-dimensional reconstruction and the integration of the large-scale threedimensional landscape and the metric building.

  2. 4D micro-CT for cardiac and perfusion applications with view under sampling

    NASA Astrophysics Data System (ADS)

    Badea, Cristian T.; Johnston, Samuel M.; Qi, Yi; Johnson, G. Allan

    2011-06-01

    Micro-CT is commonly used in preclinical studies to provide anatomical information. There is growing interest in obtaining functional measurements from 4D micro-CT. We report here strategies for 4D micro-CT with a focus on two applications: (i) cardiac imaging based on retrospective gating and (ii) pulmonary perfusion using multiple contrast injections/rotations paradigm. A dual source micro-CT system is used for image acquisition with a sampling rate of 20 projections per second. The cardiac micro-CT protocol involves the use of a liposomal blood pool contrast agent. Fast scanning of free breathing mice is achieved using retrospective gating. The ECG and respiratory signals are used to sort projections into ten cardiac phases. The pulmonary perfusion protocol uses a conventional contrast agent (Isovue 370) delivered by a micro-injector in four injections separated by 2 min intervals to allow for clearance. Each injection is synchronized with the rotation of the animal, and each of the four rotations is started with an angular offset of 22.5 from the starting angle of the previous rotation. Both cardiac and perfusion protocols result in an irregular angular distribution of projections that causes significant streaking artifacts in reconstructions when using traditional filtered backprojection (FBP) algorithms. The reconstruction involves the use of the point spread function of the micro-CT system for each time point, and the analysis of the distribution of the reconstructed data in the Fourier domain. This enables us to correct for angular inconsistencies via deconvolution and identify regions where data is missing. The missing regions are filled with data from a high quality but temporally averaged prior image reconstructed with all available projections. Simulations indicate that deconvolution successfully removes the streaking artifacts while preserving temporal information. 4D cardiac micro-CT in a mouse was performed with adequate image quality at isotropic

  3. Relative charge transfer cross section from Rb (4d)

    NASA Astrophysics Data System (ADS)

    Shah, M. H.; Camp, H. A.; Trachy, M. L.; Fléchard, X.; Gearba, M. A.; Nguyen, H.; Brédy, R.; Lundeen, S. R.; Depaola, B. D.

    2005-08-01

    Relative charge transfer cross section measurements for the excited state Rb(4d) with 7keV Na+ is reported. The specific channels reported are Na++Rb(4d5/2)→Na(nl)+Rb+ , where the dominant transfer cross sections channels were nl=3d and 4s . Using a combination of a magneto-optical trap and recoil ion momentum spectroscopy (MOTRIMS methodology), the cross sections were measured relative to the previously studied Na++Rb(5s,5p) systems at the same collision energy.

  4. Relative charge transfer cross section from Rb(4d)

    SciTech Connect

    Shah, M.H.; Camp, H.A.; Trachy, M.L.; De Paola, B.D.; Flechard, X.; Gearba, M.A.; Nguyen, H.; Bredy, R.; Lundeen, S.R.

    2005-08-15

    Relative charge transfer cross section measurements for the excited state Rb(4d) with 7 keV Na{sup +} is reported. The specific channels reported are Na{sup +}+Rb(4d{sub 5/2}){yields}Na(nl)+Rb{sup +}, where the dominant transfer cross sections channels were nl=3d and 4s. Using a combination of a magneto-optical trap and recoil ion momentum spectroscopy (MOTRIMS methodology), the cross sections were measured relative to the previously studied Na{sup +}+Rb(5s,5p) systems at the same collision energy.

  5. The 4-D approach to visual control of autonomous systems

    NASA Technical Reports Server (NTRS)

    Dickmanns, Ernst D.

    1994-01-01

    Development of a 4-D approach to dynamic machine vision is described. Core elements of this method are spatio-temporal models oriented towards objects and laws of perspective projection in a foward mode. Integration of multi-sensory measurement data was achieved through spatio-temporal models as invariants for object recognition. Situation assessment and long term predictions were allowed through maintenance of a symbolic 4-D image of processes involving objects. Behavioral capabilities were easily realized by state feedback and feed-foward control.

  6. Emerging Applications of Abdominal 4D Flow MRI

    PubMed Central

    Roldán-Alzate, Alejandro; Francois, Christopher J.; Wieben, Oliver; Reeder, Scott B.

    2016-01-01

    OBJECTIVE Comprehensive assessment of abdominal hemodynamics is crucial for many clinical diagnoses but is challenged by a tremendous complexity of anatomy, normal physiology, and a wide variety of pathologic abnormalities. This article introduces 4D flow MRI as a powerful technique for noninvasive assessment of the hemodynamics of abdominal vascular territories. CONCLUSION Four-dimensional flow MRI provides clinicians with a more extensive and straightforward approach to evaluate disorders that affect blood flow in the abdomen. This review presents a series of clinical cases to illustrate the utility of 4D flow MRI in the comprehensive assessment of the abdominal circulation. PMID:27187681

  7. High temporal and high spatial resolution MR angiography (4D-MRA).

    PubMed

    Hadizadeh, D R; Marx, C; Gieseke, J; Schild, H H; Willinek, W A

    2014-09-01

    In the first decade of the twenty-first century, whole-body magnetic resonance scanners with high field strengths (and thus potentially better signal-to-noise ratios) were developed. At the same time, parallel imaging and "echo-sharing" techniques were refined to allow for increasingly high spatial and temporal resolution in dynamic magnetic resonance angiography ("time-resolved" = TR-MRA). This technological progress facilitated tracking the passage of intra-venously administered contrast agent boluses as well as the acquisition of volume data sets at high image refresh rates ("4D-MRA"). This opened doors for many new applications in non-invasive vascular imaging, including simultaneous anatomic and functional analysis of many vascular pathologies including arterio-venous malformations. Different methods were established to acquire 4D-MRA using various strategies to acquire k-space trajectories over time in order to optimize imaging according to clinical needs. These include "keyhole"-based techniques (e. g. 4D-TRAK), TRICKS - both with and without projection - and HYPR-reconstruction, TREAT, and TWIST. Some of these techniques were first introduced in the 1980 s and 1990 s, were later enhanced and modified, and finally implemented in the products of major vendors. In the last decade, a large number of studies on the clinical applications of TR-MRA was published. This manuscript provides an overview of the development of TR-MRA methods and the 4D-MRA techniques as they are currently used in the diagnosis, treatment and follow-up of vascular diseases in various parts of the body. PMID:24955647

  8. Scatter correction of vessel dropout behind highly attenuating structures in 4D-DSA

    NASA Astrophysics Data System (ADS)

    Hermus, James; Mistretta, Charles; Szczykutowicz, Timothy P.

    2015-03-01

    In Computed Tomographic (CT) image reconstruction for 4 dimensional digital subtraction angiography (4D-DSA), loss of vessel contrast has been observed behind highly attenuating anatomy, such as large contrast filled aneurysms. Although this typically occurs only in a limited range of projection angles, the observed contrast time course can be altered. In this work we propose an algorithm to correct for highly attenuating anatomy within the fill projection data, i.e. aneurysms. The algorithm uses a 3D-SA volume to create a correction volume that is multiplied by the 4D-DSA volume in order to correct for signal dropout within the 4D-DSA volume. The algorithm was designed to correct for highly attenuating material in the fill volume only, however with alterations to a single step of the algorithm, artifacts due to highly attenuating materials in the mask volume (i.e. dental implants) can be mitigated as well. We successfully applied our algorithm to a case of vessel dropout due to the presence of a large attenuating aneurysm. The performance was qualified visually as the affected vessel no longer dropped out on corrected 4D-DSA time frames. The correction was quantified by plotting the signal intensity along the vessel. Our analysis demonstrated our correction does not alter vessel signal values outside of the vessel dropout region but does increase the vessel values within the dropout region as expected. We have demonstrated that this correction algorithm acts to correct vessel dropout in areas with highly attenuating materials.

  9. A phantom for testing of 4D-CT for radiotherapy of small lesions

    SciTech Connect

    Dunn, L.; Kron, T.; Taylor, M. L.; Callahan, J.; Franich, R. D.

    2012-09-15

    Purpose: The use of time-resolved four-dimensional computed tomography (4D-CT) in radiotherapy requires strict quality assurance to ensure the accuracy of motion management protocols. The aim of this work was to design and test a phantom capable of large amplitude motion for use in 4D-CT, with particular interest in small lesions typical for stereotactic body radiotherapy. Methods: The phantom of 'see-saw' design is light weight, capable of including various sample materials and compatible with several surrogate marker signal acquisition systems. It is constructed of polymethylmethacrylate (Perspex) and its movement is controlled via a dc motor and drive wheel. It was tested using two CT scanners with different 4D acquisition methods: the Philips Brilliance Big Bore CT (helical scan, pressure belt) and a General Electric Discovery STE PET/CT (axial scan, infrared marker). Amplitudes ranging from 1.5 to 6.0 cm and frequencies of up to 40 cycles per minute were used to study the effect of motion on image quality. Maximum intensity projections (MIPs), as well as average intensity projections (AIPs) of moving objects were investigated and their quality dependence on the number of phase reconstruction bins assessed. Results: CT number discrepancies between moving and stationary objects were found to have no systematic dependence on amplitude, frequency, or specific interphase variability. MIP-delineated amplitudes of motion were found to match physical phantom amplitudes to within 2 mm for all motion scenarios tested. Objects undergoing large amplitude motions (>3.0 cm) were shown to cause artefacts in MIP and AIP projections when ten phase bins were assigned. This problem can be mitigated by increasing the number of phase bins in a 4D-CT scan. Conclusions: The phantom was found to be a suitable tool for evaluating the image quality of 4D-CT motion management technology, as well as providing a quality assurance tool for intercenter/intervendor testing of commercial 4D

  10. Resolution enhancement of lung 4D-CT via group-sparsity

    SciTech Connect

    Bhavsar, Arnav; Wu, Guorong; Shen, Dinggang; Lian, Jun

    2013-12-15

    Purpose: 4D-CT typically delivers more accurate information about anatomical structures in the lung, over 3D-CT, due to its ability to capture visual information of the lung motion across different respiratory phases. This helps to better determine the dose during radiation therapy for lung cancer. However, a critical concern with 4D-CT that substantially compromises this advantage is the low superior-inferior resolution due to less number of acquired slices, in order to control the CT radiation dose. To address this limitation, the authors propose an approach to reconstruct missing intermediate slices, so as to improve the superior-inferior resolution.Methods: In this method the authors exploit the observation that sampling information across respiratory phases in 4D-CT can be complimentary due to lung motion. The authors’ approach uses this locally complimentary information across phases in a patch-based sparse-representation framework. Moreover, unlike some recent approaches that treat local patches independently, the authors’ approach employs the group-sparsity framework that imposes neighborhood and similarity constraints between patches. This helps in mitigating the trade-off between noise robustness and structure preservation, which is an important consideration in resolution enhancement. The authors discuss the regularizing ability of group-sparsity, which helps in reducing the effect of noise and enables better structural localization and enhancement.Results: The authors perform extensive experiments on the publicly available DIR-Lab Lung 4D-CT dataset [R. Castillo, E. Castillo, R. Guerra, V. Johnson, T. McPhail, A. Garg, and T. Guerrero, “A framework for evaluation of deformable image registration spatial accuracy using large landmark point sets,” Phys. Med. Biol. 54, 1849–1870 (2009)]. First, the authors carry out empirical parametric analysis of some important parameters in their approach. The authors then demonstrate, qualitatively as well as

  11. SU-D-18C-01: A Novel 4D-MRI Technology Based On K-Space Retrospective Sorting

    SciTech Connect

    Liu, Y; Yin, F; Cai, J

    2014-06-01

    Purpose: Current 4D-MRI techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of an entirely new framework of 4D-MRI based on k-space retrospective sorting. Methods: An important challenge of the proposed technique is to determine the number of repeated scans(NR) required to obtain sufficient k-space data for 4D-MRI. To do that, simulations using 29 cancer patients' respiratory profiles were performed to derive the relationship between data acquisition completeness(Cp) and NR, also relationship between NR(Cp=95%) and the following factors: total slice(NS), respiratory phase bin length(Lb), frame rate(fr), resolution(R) and image acquisition starting-phase(P0). To evaluate our technique, a computer simulation study on a 4D digital human phantom (XCAT) were conducted with regular breathing (fr=0.5Hz; R=256×256). A 2D echo planer imaging(EPI) MRI sequence were assumed to acquire raw k-space data, with respiratory signal and acquisition time for each k-space data line recorded simultaneously. K-space data was re-sorted based on respiratory phases. To evaluate 4D-MRI image quality, tumor trajectories were measured and compared with the input signal. Mean relative amplitude difference(D) and cross-correlation coefficient(CC) are calculated. Finally, phase-sharing sliding window technique was applied to investigate the feasibility of generating ultra-fast 4D-MRI. Result: Cp increased with NR(Cp=100*[1-exp(-0.19*NR)], when NS=30, Lb=100%/6). NR(Cp=95%) was inversely-proportional to Lb (r=0.97), but independent of other factors. 4D-MRI on XCAT demonstrated highly accurate motion information (D=0.67%, CC=0.996) with much less artifacts than those on image-based sorting 4D-MRI. Ultra-fast 4D-MRI with an apparent temporal resolution of 10 frames/second was reconstructed using the phase-sharing sliding window technique. Conclusions: A novel 4D

  12. 4D Tumorigenesis Model for Quantitating Coalescence, Directed Cell Motility and Chemotaxis, Identifying Unique Cell Behaviors, and Testing Anticancer Drugs.

    PubMed

    Kuhl, Spencer; Voss, Edward; Scherer, Amanda; Lusche, Daniel F; Wessels, Deborah; Soll, David R

    2016-01-01

    A 4D high-resolution computer-assisted reconstruction and motion analysis system has been developed and applied to the long-term (14-30 days) analysis of cancer cells migrating and aggregating within a 3D matrix. 4D tumorigenesis models more closely approximate the tumor microenvironment than 2D substrates and, therefore, are improved tools for elucidating the interactions within the tumor microenvironment that promote growth and metastasis. The model we describe here can be used to analyze the growth of tumor cells, aggregate coalescence, directed cell motility and chemotaxis, matrix degradation, the effects of anticancer drugs, and the behavior of immune and endothelial cells mixed with cancer cells. The information given in this chapter is also intended to acquaint the reader with computer-assisted methods and algorithms that can be used for high-resolution 3D reconstruction and quantitative motion analysis. PMID:27271907

  13. 4D numerical observer for lesion detection in respiratory-gated PET

    PubMed Central

    Lorsakul, Auranuch; Li, Quanzheng; Trott, Cathryn M.; Hoog, Christopher; Petibon, Yoann; Ouyang, Jinsong; Laine, Andrew F.; El Fakhri, Georges

    2014-01-01

    Purpose: Respiratory-gated positron emission tomography (PET)/computed tomography protocols reduce lesion smearing and improve lesion detection through a synchronized acquisition of emission data. However, an objective assessment of image quality of the improvement gained from respiratory-gated PET is mainly limited to a three-dimensional (3D) approach. This work proposes a 4D numerical observer that incorporates both spatial and temporal informations for detection tasks in pulmonary oncology. Methods: The authors propose a 4D numerical observer constructed with a 3D channelized Hotelling observer for the spatial domain followed by a Hotelling observer for the temporal domain. Realistic 18F-fluorodeoxyglucose activity distributions were simulated using a 4D extended cardiac torso anthropomorphic phantom including 12 spherical lesions at different anatomical locations (lower, upper, anterior, and posterior) within the lungs. Simulated data based on Monte Carlo simulation were obtained using geant4 application for tomographic emission (GATE). Fifty noise realizations of six respiratory-gated PET frames were simulated by GATE using a model of the Siemens Biograph mMR scanner geometry. PET sinograms of the thorax background and pulmonary lesions that were simulated separately were merged to generate different conditions of the lesions to the background (e.g., lesion contrast and motion). A conventional ordered subset expectation maximization (OSEM) reconstruction (5 iterations and 6 subsets) was used to obtain: (1) gated, (2) nongated, and (3) motion-corrected image volumes (a total of 3200 subimage volumes: 2400 gated, 400 nongated, and 400 motion-corrected). Lesion-detection signal-to-noise ratios (SNRs) were measured in different lesion-to-background contrast levels (3.5, 8.0, 9.0, and 20.0), lesion diameters (10.0, 13.0, and 16.0 mm), and respiratory motion displacements (17.6–31.3 mm). The proposed 4D numerical observer applied on multiple-gated images was

  14. 4D numerical observer for lesion detection in respiratory-gated PET

    SciTech Connect

    Lorsakul, Auranuch; Li, Quanzheng; Ouyang, Jinsong; El Fakhri, Georges; Trott, Cathryn M.; Hoog, Christopher; Petibon, Yoann; Laine, Andrew F.

    2014-10-15

    Purpose: Respiratory-gated positron emission tomography (PET)/computed tomography protocols reduce lesion smearing and improve lesion detection through a synchronized acquisition of emission data. However, an objective assessment of image quality of the improvement gained from respiratory-gated PET is mainly limited to a three-dimensional (3D) approach. This work proposes a 4D numerical observer that incorporates both spatial and temporal informations for detection tasks in pulmonary oncology. Methods: The authors propose a 4D numerical observer constructed with a 3D channelized Hotelling observer for the spatial domain followed by a Hotelling observer for the temporal domain. Realistic {sup 18}F-fluorodeoxyglucose activity distributions were simulated using a 4D extended cardiac torso anthropomorphic phantom including 12 spherical lesions at different anatomical locations (lower, upper, anterior, and posterior) within the lungs. Simulated data based on Monte Carlo simulation were obtained using GEANT4 application for tomographic emission (GATE). Fifty noise realizations of six respiratory-gated PET frames were simulated by GATE using a model of the Siemens Biograph mMR scanner geometry. PET sinograms of the thorax background and pulmonary lesions that were simulated separately were merged to generate different conditions of the lesions to the background (e.g., lesion contrast and motion). A conventional ordered subset expectation maximization (OSEM) reconstruction (5 iterations and 6 subsets) was used to obtain: (1) gated, (2) nongated, and (3) motion-corrected image volumes (a total of 3200 subimage volumes: 2400 gated, 400 nongated, and 400 motion-corrected). Lesion-detection signal-to-noise ratios (SNRs) were measured in different lesion-to-background contrast levels (3.5, 8.0, 9.0, and 20.0), lesion diameters (10.0, 13.0, and 16.0 mm), and respiratory motion displacements (17.6–31.3 mm). The proposed 4D numerical observer applied on multiple-gated images was

  15. 2,4-Dichlorophenoxyacetic acid (2,4-D)

    Integrated Risk Information System (IRIS)

    2,4 - Dichlorophenoxyacetic acid ( 2,4 - D ) ; CASRN 94 - 75 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Asses

  16. Enterococcus faecalis promotes osteoclastogenesis and semaphorin 4D expression.

    PubMed

    Wang, Shuai; Deng, Zuhui; Seneviratne, Chaminda J; Cheung, Gary S P; Jin, Lijian; Zhao, Baohong; Zhang, Chengfei

    2015-10-01

    Enterococcus faecalis is considered a major bacterial pathogen implicated in endodontic infections and contributes considerably to periapical periodontitis. This study aimed to investigate the potential mechanisms by which E. faecalis accounts for the bone destruction in periapical periodontitis in vitro. Osteoclast precursor RAW264.7 cells were treated with E. faecalis ATCC 29212 and a wild strain of E. faecalis derived clinically from an infected root canal. The results showed that, to some extent, E. faecalis induced the RAW264.7 cells to form tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclast-like cells. This pathogen markedly stimulated RAW264.7 cells to express semaphorin 4D (Sema4D), which inhibits bone formation. Once RAW264.7 cells were primed by low-dose receptor activator of nuclear factor-kappa B ligand (RANKL), E. faecalis could significantly increase the production of TRAP-positive multinucleated cells and up-regulate the expression of osteoclast-specific markers, including NFATc1, TRAP and cathepsin K. Both p38 and ERK1/2 MAPK signaling pathways were activated by E. faecalis in RANKL-primed RAW264.7 cells, and meanwhile the expression of Sema4D was highly increased. In conclusion, E. faecalis may greatly contribute to the bone resorption in periapical periodontitis by promoting RANKL-dependent osteoclastogenesis and expression of Sema4D through activation of p38 and ERK1/2 MAPK signaling pathways.

  17. 4D MR imaging using robust internal respiratory signal

    NASA Astrophysics Data System (ADS)

    Hui, CheukKai; Wen, Zhifei; Stemkens, Bjorn; Tijssen, R. H. N.; van den Berg, C. A. T.; Hwang, Ken-Pin; Beddar, Sam

    2016-05-01

    The purpose of this study is to investigate the feasibility of using internal respiratory (IR) surrogates to sort four-dimensional (4D) magnetic resonance (MR) images. The 4D MR images were constructed by acquiring fast 2D cine MR images sequentially, with each slice scanned for more than one breathing cycle. The 4D volume was then sorted retrospectively using the IR signal. In this study, we propose to use multiple low-frequency components in the Fourier space as well as the anterior body boundary as potential IR surrogates. From these potential IR surrogates, we used a clustering algorithm to identify those that best represented the respiratory pattern to derive the IR signal. A study with healthy volunteers was performed to assess the feasibility of the proposed IR signal. We compared this proposed IR signal with the respiratory signal obtained using respiratory bellows. Overall, 99% of the IR signals matched the bellows signals. The average difference between the end inspiration times in the IR signal and bellows signal was 0.18 s in this cohort of matching signals. For the acquired images corresponding to the other 1% of non-matching signal pairs, the respiratory motion shown in the images was coherent with the respiratory phases determined by the IR signal, but not the bellows signal. This suggested that the IR signal determined by the proposed method could potentially correct the faulty bellows signal. The sorted 4D images showed minimal mismatched artefacts and potential clinical applicability. The proposed IR signal therefore provides a feasible alternative to effectively sort MR images in 4D.

  18. Sparsely-sampled High-resolution 4-D Experiments for Efficient Backbone Resonance Assignment of Disordered Proteins

    PubMed Central

    Wen, Jie; Wu, Jihui; Zhou, Pei

    2011-01-01

    Intrinsically disordered proteins (IDPs) play important roles in many critical cellular processes. Due to their limited chemical shift dispersion, IDPs often require four pairs of resonance connectivities (Hα, Cα, Cβ and CO) for establishing sequential backbone assignment. Because most conventional 4-D triple-resonance experiments share an overlapping Cα evolution period, combining existing 4-D experiments does not offer an optimal solution for non-redundant collection of a complete set of backbone resonances. Using alternative chemical shift evolution schemes, we propose a new pair of 4-D triple resonance experiments—HA(CA)CO(CA)NH/HA(CA)CONH—that complement the 4-D HNCACB/HN(CO)CACB experiments to provide complete backbone resonance information. Collection of high-resolution 4-D spectra with sparse sampling and FFT-CLEAN processing enables efficient acquisition and assignment of complete backbone resonances of IDPs. Importantly, because the CLEAN procedure iteratively identifies resonance signals and removes their associating aliasing artifacts, it greatly reduces the dependence of the reconstruction quality on sampling schemes and produces high-quality spectra even with less-than-optimal sampling schemes. PMID:21277815

  19. Cyclic reconstruction of 4D retinal blood flow with pulse synchronization

    NASA Astrophysics Data System (ADS)

    Schmoll, Tilman; Lasser, Theo; Leitgeb, Rainer A.

    2009-02-01

    Doppler OCT systems allow nowadays to visualize quantitative and qualitative angiographic maps of retinal tissue. We equipped the instrument with a pulse oximeter and recorded the pulse synchronously with the resonant Doppler flow data. Recombination of tomograms according to the heart beat cycles yields full volumes for each cycle instant. We believe such multi-dimensional functional information and the ability to monitor dynamic processes over time to open exciting perspectives that ultimately contribute to a better understanding of retinal physiology and patho-physiology in-vivo.

  20. SU-C-9A-06: The Impact of CT Image Used for Attenuation Correction in 4D-PET

    SciTech Connect

    Cui, Y; Bowsher, J; Yan, S; Cai, J; Das, S; Yin, F

    2014-06-01

    Purpose: To evaluate the appropriateness of using 3D non-gated CT image for attenuation correction (AC) in a 4D-PET (gated PET) imaging protocol used in radiotherapy treatment planning simulation. Methods: The 4D-PET imaging protocol in a Siemens PET/CT simulator (Biograph mCT, Siemens Medical Solutions, Hoffman Estates, IL) was evaluated. CIRS Dynamic Thorax Phantom (CIRS Inc., Norfolk, VA) with a moving glass sphere (8 mL) in the middle of its thorax portion was used in the experiments. The glass was filled with {sup 18}F-FDG and was in a longitudinal motion derived from a real patient breathing pattern. Varian RPM system (Varian Medical Systems, Palo Alto, CA) was used for respiratory gating. Both phase-gating and amplitude-gating methods were tested. The clinical imaging protocol was modified to use three different CT images for AC in 4D-PET reconstruction: first is to use a single-phase CT image to mimic actual clinical protocol (single-CT-PET); second is to use the average intensity projection CT (AveIP-CT) derived from 4D-CT scanning (AveIP-CT-PET); third is to use 4D-CT image to do the phase-matched AC (phase-matching- PET). Maximum SUV (SUVmax) and volume of the moving target (glass sphere) with threshold of 40% SUVmax were calculated for comparison between 4D-PET images derived with different AC methods. Results: The SUVmax varied 7.3%±6.9% over the breathing cycle in single-CT-PET, compared to 2.5%±2.8% in AveIP-CT-PET and 1.3%±1.2% in phasematching PET. The SUVmax in single-CT-PET differed by up to 15% from those in phase-matching-PET. The target volumes measured from single- CT-PET images also presented variations up to 10% among different phases of 4D PET in both phase-gating and amplitude-gating experiments. Conclusion: Attenuation correction using non-gated CT in 4D-PET imaging is not optimal process for quantitative analysis. Clinical 4D-PET imaging protocols should consider phase-matched 4D-CT image if available to achieve better accuracy.

  1. Similarity-regulation of OS-EM for accelerated SPECT reconstruction

    NASA Astrophysics Data System (ADS)

    Vaissier, P. E. B.; Beekman, F. J.; Goorden, M. C.

    2016-06-01

    Ordered subsets expectation maximization (OS-EM) is widely used to accelerate image reconstruction in single photon emission computed tomography (SPECT). Speedup of OS-EM over maximum likelihood expectation maximization (ML-EM) is close to the number of subsets used. Although a high number of subsets can shorten reconstruction times significantly, it can also cause severe image artifacts such as improper erasure of reconstructed activity if projections contain few counts. We recently showed that such artifacts can be prevented by using a count-regulated OS-EM (CR-OS-EM) algorithm which automatically adapts the number of subsets for each voxel based on the estimated number of counts that the voxel contributed to the projections. While CR-OS-EM reached high speed-up over ML-EM in high-activity regions of images, speed in low-activity regions could still be very slow. In this work we propose similarity-regulated OS-EM (SR-OS-EM) as a much faster alternative to CR-OS-EM. SR-OS-EM also automatically and locally adapts the number of subsets, but it uses a different criterion for subset regulation: the number of subsets that is used for updating an individual voxel depends on how similar the reconstruction algorithm would update the estimated activity in that voxel with different subsets. Reconstructions of an image quality phantom and in vivo scans show that SR-OS-EM retains all of the favorable properties of CR-OS-EM, while reconstruction speed can be up to an order of magnitude higher in low-activity regions. Moreover our results suggest that SR-OS-EM can be operated with identical reconstruction parameters (including the number of iterations) for a wide range of count levels, which can be an additional advantage from a user perspective since users would only have to post-filter an image to present it at an appropriate noise level.

  2. Impact of incorporating visual biofeedback in 4D MRI.

    PubMed

    To, David T; Kim, Joshua P; Price, Ryan G; Chetty, Indrin J; Glide-Hurst, Carri K

    2016-05-08

    Precise radiation therapy (RT) for abdominal lesions is complicated by respiratory motion and suboptimal soft tissue contrast in 4D CT. 4D MRI offers improved con-trast although long scan times and irregular breathing patterns can be limiting. To address this, visual biofeedback (VBF) was introduced into 4D MRI. Ten volunteers were consented to an IRB-approved protocol. Prospective respiratory-triggered, T2-weighted, coronal 4D MRIs were acquired on an open 1.0T MR-SIM. VBF was integrated using an MR-compatible interactive breath-hold control system. Subjects visually monitored their breathing patterns to stay within predetermined tolerances. 4D MRIs were acquired with and without VBF for 2- and 8-phase acquisitions. Normalized respiratory waveforms were evaluated for scan time, duty cycle (programmed/acquisition time), breathing period, and breathing regularity (end-inhale coefficient of variation, EI-COV). Three reviewers performed image quality assessment to compare artifacts with and without VBF. Respiration-induced liver motion was calculated via centroid difference analysis of end-exhale (EE) and EI liver contours. Incorporating VBF reduced 2-phase acquisition time (4.7 ± 1.0 and 5.4 ± 1.5 min with and without VBF, respectively) while reducing EI-COV by 43.8% ± 16.6%. For 8-phase acquisitions, VBF reduced acquisition time by 1.9 ± 1.6 min and EI-COVs by 38.8% ± 25.7% despite breathing rate remaining similar (11.1 ± 3.8 breaths/min with vs. 10.5 ± 2.9 without). Using VBF yielded higher duty cycles than unguided free breathing (34.4% ± 5.8% vs. 28.1% ± 6.6%, respectively). Image grading showed that out of 40 paired evaluations, 20 cases had equivalent and 17 had improved image quality scores with VBF, particularly for mid-exhale and EI. Increased liver excursion was observed with VBF, where superior-inferior, anterior-posterior, and left-right EE-EI displacements were 14.1± 5.8, 4.9 ± 2.1, and 1.5 ± 1.0 mm, respectively, with VBF compared to 11.9

  3. 4D CT amplitude binning for the generation of a time-averaged 3D mid-position CT scan.

    PubMed

    Kruis, Matthijs F; van de Kamer, Jeroen B; Belderbos, José S A; Sonke, Jan-Jakob; van Herk, Marcel

    2014-09-21

    The purpose of this study was to develop a method to use amplitude binned 4D-CT (A-4D-CT) data for the construction of mid-position CT data and to compare the results with data created from phase-binned 4D-CT (P-4D-CT) data. For the latter purpose we have developed two measures which describe the regularity of the 4D data and we have tried to correlate these measures with the regularity of the external respiration signal. 4D-CT data was acquired for 27 patients on a combined PET-CT scanner. The 4D data were reconstructed twice, using phase and amplitude binning. The 4D frames of each dataset were registered using a quadrature-based optical flow method. After registration the deformation vector field was repositioned to the mid-position. Since amplitude-binned 4D data does not provide temporal information, we corrected the mid-position for the occupancy of the bins. We quantified the differences between the two mid-position datasets in terms of tumour offset and amplitude differences. Furthermore, we measured the standard deviation of the image intensity over the respiration after registration (σregistration) and the regularity of the deformation vector field (Delta J) to quantify the quality of the 4D-CT data. These measures were correlated to the regularity of the external respiration signal (σsignal).The two irregularity measures, Delta J and σregistration, were dependent on each other (p<0.0001, R2=0.80 for P-4D-CT, R2=0.74 for A-4D-CT). For all datasets amplitude binning resulted in lower Delta J and σregistration and large decreases led to visible quality improvements in the mid-position data. The quantity of artefact decrease was correlated to the irregularity of the external respiratory signal.The average tumour offset between the phase and amplitude binned mid-position without occupancy correction was 0.42 mm in the caudal direction (10.6% of the amplitude). After correction this was reduced to 0.16 mm in caudal direction (4.1% of the amplitude

  4. Exome sequencing identifies PDE4D mutations in acrodysostosis.

    PubMed

    Lee, Hane; Graham, John M; Rimoin, David L; Lachman, Ralph S; Krejci, Pavel; Tompson, Stuart W; Nelson, Stanley F; Krakow, Deborah; Cohn, Daniel H

    2012-04-01

    Acrodysostosis is a dominantly-inherited, multisystem disorder characterized by skeletal, endocrine, and neurological abnormalities. To identify the molecular basis of acrodysostosis, we performed exome sequencing on five genetically independent cases. Three different missense mutations in PDE4D, which encodes cyclic AMP (cAMP)-specific phosphodiesterase 4D, were found to be heterozygous in three of the cases. Two of the mutations were demonstrated to have occurred de novo, providing strong genetic evidence of causation. Two additional cases were heterozygous for de novo missense mutations in PRKAR1A, which encodes the cAMP-dependent regulatory subunit of protein kinase A and which has been recently reported to be the cause of a form of acrodysostosis resistant to multiple hormones. These findings demonstrate that acrodysostosis is genetically heterogeneous and underscore the exquisite sensitivity of many tissues to alterations in cAMP homeostasis. PMID:22464252

  5. Intelligent Vehicle Systems: A 4D/RCS Approach

    SciTech Connect

    Madhavan, Raj

    2007-04-01

    This book presents new research on autonomous mobility capabilities and shows how technological advances can be anticipated in the coming two decades. An in-depth description is presented on the theoretical foundations and engineering approaches that enable these capabilities. Chapter 1 provides a brief introduction to the 4D/RCS reference model architecture and design methodology that has proven successful in guiding the development of autonomous mobility systems. Chapters 2 through 7 provide more detailed descriptions of research that has been conducted and algorithms that have been developed to implement the various aspects of the 4D/RCS reference model architecture and design methodology. Chapters 8 and 9 discuss applications, performance measures, and standards. Chapter 10 provides a history of Army and DARPA research in autonomous ground mobility. Chapter 11 provides a perspective on the potential future developments in autonomous mobility.

  6. 4D embryonic cardiography using gated optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Jenkins, M. W.; Rothenberg, F.; Roy, D.; Nikolski, V. P.; Hu, Z.; Watanabe, M.; Wilson, D. L.; Efimov, I. R.; Rollins, A. M.

    2006-01-01

    Simultaneous imaging of very early embryonic heart structure and function has technical limitations of spatial and temporal resolution. We have developed a gated technique using optical coherence tomography (OCT) that can rapidly image beating embryonic hearts in four-dimensions (4D), at high spatial resolution (10-15 μm), and with a depth penetration of 1.5 - 2.0 mm that is suitable for the study of early embryonic hearts. We acquired data from paced, excised, embryonic chicken and mouse hearts using gated sampling and employed image processing techniques to visualize the hearts in 4D and measure physiologic parameters such as cardiac volume, ejection fraction, and wall thickness. This technique is being developed to longitudinally investigate the physiology of intact embryonic hearts and events that lead to congenital heart defects.

  7. 4D flow cardiovascular magnetic resonance consensus statement.

    PubMed

    Dyverfeldt, Petter; Bissell, Malenka; Barker, Alex J; Bolger, Ann F; Carlhäll, Carl-Johan; Ebbers, Tino; Francios, Christopher J; Frydrychowicz, Alex; Geiger, Julia; Giese, Daniel; Hope, Michael D; Kilner, Philip J; Kozerke, Sebastian; Myerson, Saul; Neubauer, Stefan; Wieben, Oliver; Markl, Michael

    2015-01-01

    Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5×1.5×1.5 - 3×3×3 mm(3), typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations. PMID:26257141

  8. Phosphodiesterase 4D gene polymorphisms in sudden sensorineural hearing loss.

    PubMed

    Chien, Chen-Yu; Tai, Shu-Yu; Wang, Ling-Feng; Hsi, Edward; Chang, Ning-Chia; Wang, Hsun-Mo; Wu, Ming-Tsang; Ho, Kuen-Yao

    2016-09-01

    The phosphodiesterase 4D (PDE4D) gene has been reported as a risk gene for ischemic stroke. The vascular factors are between the hypothesized etiologies of sudden sensorineural hearing loss (SSNHL), and this genetic effect might be attributed for its role in SSNHL. We hypothesized that genetic variants of the PDE4D gene are associated with susceptibility to SSNHL. We conducted a case-control study with 362 SSNHL cases and 209 controls. Three single nucleotide polymorphisms (SNPs) were selected. The genotypes were determined using TaqMan technology. Hardy-Weinberg equilibrium (HWE) was tested for each SNP, and genetic effects were evaluated according to three inheritance modes. We carried out sex-specific analysis to analyze the overall data. All three SNPs were in HWE. When subjects were stratified by sex, the genetic effect was only evident in females but not in males. The TT genotype of rs702553 exhibited an adjusted odds ratio (OR) of 3.83 (95 % confidence interval = 1.46-11.18) (p = 0.006) in female SSNHL. The TT genotype of SNP rs702553 was associated with female SSNHL under the recessive model (p = 0.004, OR 3.70). In multivariate logistic regression analysis, TT genotype of rs702553 was significantly associated with female SSNHL (p = 0.0043, OR 3.70). These results suggest that PDE4D gene polymorphisms influence the susceptibility for the development of SSNHL in the southern Taiwanese female population.

  9. 4D-Flow validation, numerical and experimental framework

    NASA Astrophysics Data System (ADS)

    Sansom, Kurt; Liu, Haining; Canton, Gador; Aliseda, Alberto; Yuan, Chun

    2015-11-01

    This work presents a group of assessment metrics of new 4D MRI flow sequences, an imaging modality that allows for visualization of three-dimensional pulsatile flow in the cardiovascular anatomy through time-resolved three-dimensional blood velocity measurements from cardiac-cycle synchronized MRI acquisition. This is a promising tool for clinical assessment but lacks a robust validation framework. First, 4D-MRI flow in a subject's stenotic carotid bifurcation is compared with a patient-specific CFD model using two different boundary condition methods. Second, Particle Image Velocimetry in a patient-specific phantom is used as a benchmark to compare the 4D-MRI in vivo measurements and CFD simulations under the same conditions. Comparison of estimated and measureable flow parameters such as wall shear stress, fluctuating velocity rms, Lagrangian particle residence time, will be discussed, with justification for their biomechanics relevance and the insights they can provide on the pathophysiology of arterial disease: atherosclerosis and intimal hyperplasia. Lastly, the framework is applied to a new sequence to provide a quantitative assessment. A parametric analysis on the carotid bifurcation pulsatile flow conditions will be presented and an accuracy assessment provided.

  10. Upgrade and benchmarking of a 4D treatment planning system for scanned ion beam therapy

    SciTech Connect

    Richter, D.; Schwarzkopf, A.; Trautmann, J.; Durante, M.; Kraemer, M.; Jaekel, O.; Bert, C.

    2013-05-15

    Purpose: Upgrade and benchmarking of a research 4D treatment planning system (4DTPS) suitable for realistic patient treatment planning and treatment simulations taking into account specific requirements for scanned ion beam therapy, i.e., modeling of dose heterogeneities due to interplay effects and range changes caused by patient motion and dynamic beam delivery. Methods: The 4DTPS integrates data interfaces to 4D computed tomography (4DCT), deformable image registration and clinically used motion monitoring devices. The authors implemented a novel data model for 4D image segmentation using Boolean mask volume datasets and developed an algorithm propagating a manually contoured reference contour dataset to all 4DCT phases. They further included detailed treatment simulation and dose reconstruction functionality, based on the irregular patient motion and the temporal structure of the beam delivery. The treatment simulation functionality was validated against experimental data from irradiation of moving radiographic films in air, 3D moving ionization chambers in a water phantom, and moving cells in a biological phantom with a scanned carbon ion beam. The performance of the program was compared to results obtained with predecessor programs. Results: The measured optical density distributions of the radiographic films were reproduced by the simulations to (-2 {+-} 12)%. Compared to earlier versions of the 4DTPS, the mean agreement improved by 2%, standard deviations were reduced by 7%. The simulated dose to the moving ionization chambers in water showed an agreement with the measured dose of (-1 {+-} 4)% for the typical beam configuration. The mean deviation of the simulated from the measured biologically effective dose determined via cell survival was (617 {+-} 538) mGy relative biological effectiveness corresponding to (10 {+-} 9)%. Conclusions: The authors developed a research 4DTPS suitable for realistic treatment planning on patient data and capable of simulating

  11. Selective 4D modelling framework for spatial-temporal land information management system

    NASA Astrophysics Data System (ADS)

    Doulamis, Anastasios; Soile, Sofia; Doulamis, Nikolaos; Chrisouli, Christina; Grammalidis, Nikos; Dimitropoulos, Kosmas; Manesis, Charalambos; Potsiou, Chryssy; Ioannidis, Charalabos

    2015-06-01

    This paper introduces a predictive (selective) 4D modelling framework where only the spatial 3D differences are modelled at the forthcoming time instances, while regions of no significant spatial-temporal alterations remain intact. To accomplish this, initially spatial-temporal analysis is applied between 3D digital models captured at different time instances. So, the creation of dynamic change history maps is made. Change history maps indicate spatial probabilities of regions needed further 3D modelling at forthcoming instances. Thus, change history maps are good examples for a predictive assessment, that is, to localize surfaces within the objects where a high accuracy reconstruction process needs to be activated at the forthcoming time instances. The proposed 4D Land Information Management System (LIMS) is implemented using open interoperable standards based on the CityGML framework. CityGML allows the description of the semantic metadata information and the rights of the land resources. Visualization aspects are also supported to allow easy manipulation, interaction and representation of the 4D LIMS digital parcels and the respective semantic information. The open source 3DCityDB incorporating a PostgreSQL geo-database is used to manage and manipulate 3D data and their semantics. An application is made to detect the change through time of a 3D block of plots in an urban area of Athens, Greece. Starting with an accurate 3D model of the buildings in 1983, a change history map is created using automated dense image matching on aerial photos of 2010. For both time instances meshes are created and through their comparison the changes are detected.

  12. Application of unified array calculus to connect 4-D spacetime sensing with string theory and relativity

    NASA Astrophysics Data System (ADS)

    Rauhala, U. A.

    2013-12-01

    Array algebra of photogrammetry and geodesy unified multi-linear matrix and tensor operators in an expansion of Gaussian adjustment calculus to general matrix inverses and solutions of inverse problems to find all, or some optimal, parametric solutions that satisfy the available observables. By-products in expanding array and tensor calculus to handle redundant observables resulted in general theories of estimation in mathematical statistics and fast transform technology of signal processing. Their applications in gravity modeling and system automation of multi-ray digital image and terrain matching evolved into fast multi-nonlinear differential and integral array calculus. Work since 1980's also uncovered closed-form inverse Taylor and least squares Newton-Raphson-Gauss perturbation solutions of nonlinear systems of equations. Fast nonlinear integral matching of array wavelets enabled an expansion of the bundle adjustment to 4-D stereo imaging and range sensing where real-time stereo sequence and waveform phase matching enabled data-to-info conversion and compression on-board advanced sensors. The resulting unified array calculus of spacetime sensing is applicable in virtually any math and engineering science, including recent work in spacetime physics. The paper focuses on geometric spacetime reconstruction from its image projections inspired by unified relativity and string theories. The collinear imaging equations of active object space shutter of special relativity are expanded to 4-D Lorentz transform. However, regular passive imaging and shutter inside the sensor expands the law of special relativity by a quantum geometric explanation of 4-D photogrammetry. The collinear imaging equations provide common sense explanations to the 10 (and 26) dimensional hyperspace concepts of a purely geometric string theory. The 11-D geometric M-theory is interpreted as a bundle adjustment of spacetime images using 2-D or 5-D membrane observables of image, string and

  13. 4D STEM: High efficiency phase contrast imaging using a fast pixelated detector

    NASA Astrophysics Data System (ADS)

    Yang, H.; Jones, L.; Ryll, H.; Simson, M.; Soltau, H.; Kondo, Y.; Sagawa, R.; Banba, H.; MacLaren, I.; Nellist, P. D.

    2015-10-01

    Phase contrast imaging is widely used for imaging beam sensitive and weak phase objects in electron microscopy. In this work we demonstrate the achievement of high efficient phase contrast imaging in STEM using the pnCCD, a fast direct electron pixelated detector, which records the diffraction patterns at every probe position with a speed of 1000 to 4000 frames per second, forming a 4D STEM dataset simultaneously with the incoherent Z-contrast imaging. Ptychographic phase reconstruction has been applied and the obtained complex transmission function reveals the phase of the specimen. The results using GaN and Ti, Nd- doped BiFeO3 show that this imaging mode is especially powerful for imaging light elements in the presence of much heavier elements.

  14. Probing Invisible, Excited Protein States by Non-Uniformly Sampled Pseudo-4D CEST Spectroscopy.

    PubMed

    Long, Dong; Delaglio, Frank; Sekhar, Ashok; Kay, Lewis E

    2015-09-01

    Chemical exchange saturation transfer (CEST) NMR spectroscopy is a powerful tool for studies of slow timescale protein dynamics. Typical experiments are based on recording a large number of 2D data sets and quantifying peak intensities in each of the resulting planes. A weakness of the method is that peaks must be resolved in 2D spectra, limiting applications to relatively small proteins. Resolution is significantly improved in 3D spectra but recording uniformly sampled data is time-prohibitive. Here we describe non-uniformly sampled HNCO-based pseudo-4D CEST that provides excellent resolution in reasonable measurement times. Data analysis is done through fitting in the time domain, without the need of reconstructing the frequency dimensions, exploiting previously measured accurate peak positions in reference spectra. The methodology is demonstrated on several protein systems, including a nascent form of superoxide dismutase that is implicated in neurodegenerative disease. PMID:26178142

  15. Development of 4D jaw movement visualization system for dental diagnosis support

    NASA Astrophysics Data System (ADS)

    Aoki, Yoshimitsu; Terajima, Masahiko; Nakasima, Akihiko

    2004-10-01

    A person with an asymmetric morphology of maxillofacial skeleton reportedly possesses an asymmetric jaw function and the risk to express temporomandibular disorder is high. A comprehensive analysis from the point of view of both the morphology and the function such as maxillofacial or temporomandibular joint morphology, dental occlusion, and features of mandibular movement pathways is essential. In this study, the 4D jaw movement visualization system was developed to visually understand the characteristic jaw movement, 3D maxillofacial skeleton structure, and the alignment of the upper and lower teeth of a patient. For this purpose, the 3D reconstructed images of the cranial and mandibular bones, obtained by computed tomography, were measured using a non-contact 3D measuring device, and the obtained morphological images of teeth model were integrated and activated on the 6 DOF jaw movement data. This system was experimentally applied and visualized in a jaw deformity patient and its usability as a clinical diagnostic support system was verified.

  16. 4D Hyperspherical Harmonic (HyperSPHARM) Representation of Multiple Disconnected Brain Subcortical Structures

    PubMed Central

    Hosseinbor, A. Pasha; Chung, Moo K.; Schaefer, Stacey M.; van Reekum, Carien M.; Peschke-Schmitz, Lara; Sutterer, Matt; Alexander, Andrew L.; Davidson, Richard J.

    2014-01-01

    We present a novel surface parameterization technique using hyperspherical harmonics (HSH) in representing compact, multiple, disconnected brain subcortical structures as a single analytic function. The proposed hyperspherical harmonic representation (HyperSPHARM) has many advantages over the widely used spherical harmonic (SPHARM) parameterization technique. SPHARM requires flattening 3D surfaces to 3D sphere which can be time consuming for large surface meshes, and can’t represent multiple disconnected objects with single parameterization. On the other hand, HyperSPHARM treats 3D object, via simple stereographic projection, as a surface of 4D hypersphere with extremely large radius, hence avoiding the computationally demanding flattening process. HyperSPHARM is shown to achieve a better reconstruction with only 5 basis compared to SPHARM that requires more than 441. PMID:24505716

  17. 4D Proton treatment planning strategy for mobile lung tumors

    SciTech Connect

    Kang Yixiu; Zhang Xiaodong; Chang, Joe Y.; Wang He; Wei Xiong; Liao Zhongxing; Komaki, Ritsuko; Cox, James D.; Balter, Peter A.; Liu, Helen; Zhu, X. Ronald; Mohan, Radhe; Dong Lei . E-mail: ldong@mdanderson.org

    2007-03-01

    Purpose: To investigate strategies for designing compensator-based 3D proton treatment plans for mobile lung tumors using four-dimensional computed tomography (4DCT) images. Methods and Materials: Four-dimensional CT sets for 10 lung cancer patients were used in this study. The internal gross tumor volume (IGTV) was obtained by combining the tumor volumes at different phases of the respiratory cycle. For each patient, we evaluated four planning strategies based on the following dose calculations: (1) the average (AVE) CT; (2) the free-breathing (FB) CT; (3) the maximum intensity projection (MIP) CT; and (4) the AVE CT in which the CT voxel values inside the IGTV were replaced by a constant density (AVE{sub R}IGTV). For each strategy, the resulting cumulative dose distribution in a respiratory cycle was determined using a deformable image registration method. Results: There were dosimetric differences between the apparent dose distribution, calculated on a single CT dataset, and the motion-corrected 4D dose distribution, calculated by combining dose distributions delivered to each phase of the 4DCT. The AVE{sub R}IGTV plan using a 1-cm smearing parameter had the best overall target coverage and critical structure sparing. The MIP plan approach resulted in an unnecessarily large treatment volume. The AVE and FB plans using 1-cm smearing did not provide adequate 4D target coverage in all patients. By using a larger smearing value, adequate 4D target coverage could be achieved; however, critical organ doses were increased. Conclusion: The AVE{sub R}IGTV approach is an effective strategy for designing proton treatment plans for mobile lung tumors.

  18. Localization of 4D gravity on pure geometrical thick branes

    SciTech Connect

    Barbosa-Cendejas, Nandinii; Herrera-Aguilar, Alfredo

    2006-04-15

    We consider the generation of thick brane configurations in a pure geometric Weyl integrable 5D spacetime which constitutes a non-Riemannian generalization of Kaluza-Klein (KK) theory. In this framework, we show how 4D gravity can be localized on a scalar thick brane which does not necessarily respect reflection symmetry, generalizing in this way several previous models based on the Randall-Sundrum (RS) system and avoiding both, the restriction to orbifold geometries and the introduction of the branes in the action by hand. We first obtain a thick brane solution that preserves 4D Poincare invariance and breaks Z{sub 2}-symmetry along the extra dimension which, indeed, can be either compact or extended, and supplements brane solutions previously found by other authors. In the noncompact case, this field configuration represents a thick brane with positive energy density centered at y=c{sub 2}, whereas pairs of thick branes arise in the compact case. Remarkably, the Weylian scalar curvature is nonsingular along the fifth dimension in the noncompact case, in contraposition to the RS thin brane system. We also recast the wave equations of the transverse traceless modes of the linear fluctuations of the classical background into a Schroedinger's equation form with a volcano potential of finite bottom in both the compact and the extended cases. We solve Schroedinger equation for the massless zero mode m{sup 2}=0 and obtain a single bound wave function which represents a stable 4D graviton. We also get a continuum gapless spectrum of KK states with m{sup 2}>0 that are suppressed at y=c{sub 2} and turn asymptotically into plane waves.

  19. Phase and amplitude binning for 4D-CT imaging

    NASA Astrophysics Data System (ADS)

    Abdelnour, A. F.; Nehmeh, S. A.; Pan, T.; Humm, J. L.; Vernon, P.; Schöder, H.; Rosenzweig, K. E.; Mageras, G. S.; Yorke, E.; Larson, S. M.; Erdi, Y. E.

    2007-07-01

    We compare the consistency and accuracy of two image binning approaches used in 4D-CT imaging. One approach, phase binning (PB), assigns each breathing cycle 2π rad, within which the images are grouped. In amplitude binning (AB), the images are assigned bins according to the breathing signal's full amplitude. To quantitate both approaches we used a NEMA NU2-2001 IEC phantom oscillating in the axial direction and at random frequencies and amplitudes, approximately simulating a patient's breathing. 4D-CT images were obtained using a four-slice GE Lightspeed CT scanner operating in cine mode. We define consistency error as a measure of ability to correctly bin over repeated cycles in the same field of view. Average consistency error μe ± σe in PB ranged from 18% ± 20% to 30% ± 35%, while in AB the error ranged from 11% ± 14% to 20% ± 24%. In PB nearly all bins contained sphere slices. AB was more accurate, revealing empty bins where no sphere slices existed. As a proof of principle, we present examples of two non-small cell lung carcinoma patients' 4D-CT lung images binned by both approaches. While AB can lead to gaps in the coronal images, depending on the patient's breathing pattern, PB exhibits no gaps but suffers visible artifacts due to misbinning, yielding images that cover a relatively large amplitude range. AB was more consistent, though often resulted in gaps when no data existed due to patients' breathing pattern. We conclude AB is more accurate than PB. This has important consequences to treatment planning and diagnosis.

  20. Non-spherical particle generation from 4D optofluidic fabrication.

    PubMed

    Paulsen, Kevin S; Chung, Aram J

    2016-08-01

    Particles with non-spherical shapes can exhibit properties which are not available from spherical shaped particles. Complex shaped particles can provide unique benefits for areas such as drug delivery, tissue engineering, structural materials, and self-assembly building blocks. Current methods of creating complex shaped particles such as 3D printing, photolithography, and imprint lithography are limited by either slow speeds, shape limitations, or expensive processes. Previously, we presented a novel microfluidic flow lithography fabrication scheme combined with fluid inertia called optofluidic fabrication for the creation of complex shaped three-dimensional (3D) particles. This process was able to address the aforementioned limits and overcome two-dimensional shape limitations faced by traditional flow lithography methods; however, all of the created 3D particle shapes displayed top-down symmetry. Here, by introducing the time dimension into our existing optofluidic fabrication process, we break this top-down symmetry, generating fully asymmetric 3D particles where we termed the process: four-dimensional (4D) optofluidic fabrication. This 4D optofluidic fabrication is comprised of three sequential procedures. First, density mismatched precursor fluids flow past pillars within fluidic channels to manipulate the flow cross sections via fluid inertia. Next, the time dimension is incorporated by stopping the flow and allowing the denser fluids to settle by gravity to create asymmetric flow cross sections. Finally, the fluids are exposed to patterned ultraviolet (UV) light in order to polymerize fully asymmetric 3D-shaped particles. By varying inertial flow shaping, gravity-induced flow shaping, and UV light patterns, 4D optofluidic fabrication can create an infinite set of complex shaped asymmetric particles. PMID:27092661

  1. Non-spherical particle generation from 4D optofluidic fabrication.

    PubMed

    Paulsen, Kevin S; Chung, Aram J

    2016-08-01

    Particles with non-spherical shapes can exhibit properties which are not available from spherical shaped particles. Complex shaped particles can provide unique benefits for areas such as drug delivery, tissue engineering, structural materials, and self-assembly building blocks. Current methods of creating complex shaped particles such as 3D printing, photolithography, and imprint lithography are limited by either slow speeds, shape limitations, or expensive processes. Previously, we presented a novel microfluidic flow lithography fabrication scheme combined with fluid inertia called optofluidic fabrication for the creation of complex shaped three-dimensional (3D) particles. This process was able to address the aforementioned limits and overcome two-dimensional shape limitations faced by traditional flow lithography methods; however, all of the created 3D particle shapes displayed top-down symmetry. Here, by introducing the time dimension into our existing optofluidic fabrication process, we break this top-down symmetry, generating fully asymmetric 3D particles where we termed the process: four-dimensional (4D) optofluidic fabrication. This 4D optofluidic fabrication is comprised of three sequential procedures. First, density mismatched precursor fluids flow past pillars within fluidic channels to manipulate the flow cross sections via fluid inertia. Next, the time dimension is incorporated by stopping the flow and allowing the denser fluids to settle by gravity to create asymmetric flow cross sections. Finally, the fluids are exposed to patterned ultraviolet (UV) light in order to polymerize fully asymmetric 3D-shaped particles. By varying inertial flow shaping, gravity-induced flow shaping, and UV light patterns, 4D optofluidic fabrication can create an infinite set of complex shaped asymmetric particles.

  2. CMT4D (NDRG1 mutation): genotype-phenotype correlations.

    PubMed

    Ricard, Emilie; Mathis, Stéphane; Magdelaine, Corinne; Delisle, Marie-Bernadette; Magy, Laurent; Funalot, Benoît; Vallat, Jean-Michel

    2013-09-01

    Charcot-Marie-Tooth (CMT) disease is a heterogeneous condition with a large number of clinical, electrophysiological and pathological phenotypes. More than 40 genes are involved. We report a child of gypsy origin with an autosomal recessive demyelinating phenotype. Clinical data, familial history, and electrophysiological studies were in favor of a CMT4 sub-type. The characteristic N-Myc downstream-regulated gene 1 (NDRG1) mutation responsible for this CMT4D phenotype was confirmed: p.R148X. The exact molecular function of the NDRG1 protein has yet to be elucidated.

  3. Multicolor 4D Fluorescence Microscopy using Ultrathin Bessel Light Sheets.

    PubMed

    Zhao, Teng; Lau, Sze Cheung; Wang, Ying; Su, Yumian; Wang, Hao; Cheng, Aifang; Herrup, Karl; Ip, Nancy Y; Du, Shengwang; Loy, M M T

    2016-01-01

    We demonstrate a simple and efficient method for producing ultrathin Bessel ('non-diffracting') light sheets of any color using a line-shaped beam and an annulus filter. With this robust and cost-effective technology, we obtained two-color, 3D images of biological samples with lateral/axial resolution of 250 nm/400 nm, and high-speed, 4D volume imaging of 20 μm sized live sample at 1 Hz temporal resolution. PMID:27189786

  4. Oblique sounding using the DPS-4D stations in Europe

    NASA Astrophysics Data System (ADS)

    Mosna, Zbysek; Kouba, Daniel; Koucka Knizova, Petra; Arikan, Feza; Arikan, Orhan; Gok, Gokhan; Rejfek, Lubos

    2016-07-01

    The DPS-4D Digisondes are capable of detection of echoes from neighbouring European stations. Currently, a campaign with high-temporal resolution of 5 min is being run. Further, ionograms from regular vertical sounding with 15 min resolution provide us with oblique reflections together with vertical reflections. We analyzed profiles of electron concentration and basic ionospheric parameters derived from the ionograms. We compared results derived from reflections from the ionosphere above the stations (vertical sounding) with information derived from oblique reflections between the stations. This study is supported by the Joint TUBITAK 114E092 and AS CR 14/001 projects.

  5. Lagrangian constraints and renormalization of 4D gravity

    NASA Astrophysics Data System (ADS)

    Park, I. Y.

    2015-04-01

    It has been proposed in [21] that 4D Einstein gravity becomes effectively reduced to 3D after solving the Lagrangian analogues of the Hamiltonian and momentum constraints of the Hamiltonian quantization. The analysis in [21] was carried out at the classical/operator level. We review the proposal and make a transition to the path integral account. We then set the stage for explicitly carrying out the two-loop renormalization procedure of the resulting 3D action. We also address a potentially subtle issue in the gravity context concerning whether renormalizability does not depend on the background around which the original action is expanded.

  6. Multicolor 4D Fluorescence Microscopy using Ultrathin Bessel Light Sheets

    PubMed Central

    Zhao, Teng; Lau, Sze Cheung; Wang, Ying; Su, Yumian; Wang, Hao; Cheng, Aifang; Herrup, Karl; Ip, Nancy Y.; Du, Shengwang; Loy, M. M. T.

    2016-01-01

    We demonstrate a simple and efficient method for producing ultrathin Bessel (‘non-diffracting’) light sheets of any color using a line-shaped beam and an annulus filter. With this robust and cost-effective technology, we obtained two-color, 3D images of biological samples with lateral/axial resolution of 250 nm/400 nm, and high-speed, 4D volume imaging of 20 μm sized live sample at 1 Hz temporal resolution. PMID:27189786

  7. All the supersymmetric configurations of N=4, d=4 supergravity

    NASA Astrophysics Data System (ADS)

    Bellorín, Jorge; Ortín, Tomás

    2005-10-01

    All the supersymmetric configurations of pure, ungauged, N=4, d=4 supergravity are classified in a formalism that keeps manifest the S and T dualities of the theory. We also find simple equations that need to be satisfied by the configurations to be classical solutions of the theory. While the solutions associated to null Killing vectors were essentially classified by Tod (a classification that we refine), we find new configurations and solutions associated to timelike Killing vectors that do not satisfy Tod's rigidity hypothesis (hence, they have a nontrivial U(1) connection) and whose supersymmetry projector is associated to 1-dimensional objects (strings), although they have a trivial axion field.

  8. 4D micro-CT using fast prospective gating

    NASA Astrophysics Data System (ADS)

    Guo, Xiaolian; Johnston, Samuel M.; Qi, Yi; Johnson, G. Allan; Badea, Cristian T.

    2012-01-01

    Micro-CT is currently used in preclinical studies to provide anatomical information. But, there is also significant interest in using this technology to obtain functional information. We report here a new sampling strategy for 4D micro-CT for functional cardiac and pulmonary imaging. Rapid scanning of free-breathing mice is achieved with fast prospective gating (FPG) implemented on a field programmable gate array. The method entails on-the-fly computation of delays from the R peaks of the ECG signals or the peaks of the respiratory signals for the triggering pulses. Projection images are acquired for all cardiac or respiratory phases at each angle before rotating to the next angle. FPG can deliver the faster scan time of retrospective gating (RG) with the regular angular distribution of conventional prospective gating for cardiac or respiratory gating. Simultaneous cardio-respiratory gating is also possible with FPG in a hybrid retrospective/prospective approach. We have performed phantom experiments to validate the new sampling protocol and compared the results from FPG and RG in cardiac imaging of a mouse. Additionally, we have evaluated the utility of incorporating respiratory information in 4D cardiac micro-CT studies with FPG. A dual-source micro-CT system was used for image acquisition with pulsed x-ray exposures (80 kVp, 100 mA, 10 ms). The cardiac micro-CT protocol involves the use of a liposomal blood pool contrast agent containing 123 mg I ml-1 delivered via a tail vein catheter in a dose of 0.01 ml g-1 body weight. The phantom experiment demonstrates that FPG can distinguish the successive phases of phantom motion with minimal motion blur, and the animal study demonstrates that respiratory FPG can distinguish inspiration and expiration. 4D cardiac micro-CT imaging with FPG provides image quality superior to RG at an isotropic voxel size of 88 µm and 10 ms temporal resolution. The acquisition time for either sampling approach is less than 5 min. The

  9. 4D cone beam CT phase sorting using high frequency optical surface measurement during image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Price, G. J.; Marchant, T. E.; Parkhurst, J. M.; Sharrock, P. J.; Whitfield, G. A.; Moore, C. J.

    2011-03-01

    In image guided radiotherapy (IGRT) two of the most promising recent developments are four dimensional cone beam CT (4D CBCT) and dynamic optical metrology of patient surfaces. 4D CBCT is now becoming commercially available and finds use in treatment planning and verification, and whilst optical monitoring is a young technology, its ability to measure during treatment delivery without dose consequences has led to its uptake in many institutes. In this paper, we demonstrate the use of dynamic patient surfaces, simultaneously captured during CBCT acquisition using an optical sensor, to phase sort projection images for 4D CBCT volume reconstruction. The dual modality approach we describe means that in addition to 4D volumetric data, the system provides correlated wide field measurements of the patient's skin surface with high spatial and temporal resolution. As well as the value of such complementary data in verification and motion analysis studies, it introduces flexibility into the acquisition of the signal required for phase sorting. The specific technique used may be varied according to individual patient circumstances and the imaging target. We give details of three different methods of obtaining a suitable signal from the optical surfaces: simply following the motion of triangulation spots used to calibrate the surfaces' absolute height; monitoring the surface height in a single, arbitrarily selected, camera pixel; and tracking, in three dimensions, the movement of a surface feature. In addition to describing the system and methodology, we present initial results from a case study oesophageal cancer patient.

  10. Functional organization of the human 4D Nucleome

    PubMed Central

    Chen, Haiming; Chen, Jie; Muir, Lindsey A.; Ronquist, Scott; Meixner, Walter; Ljungman, Mats; Ried, Thomas; Smale, Stephen; Rajapakse, Indika

    2015-01-01

    The 4D organization of the interphase nucleus, or the 4D Nucleome (4DN), reflects a dynamical interaction between 3D genome structure and function and its relationship to phenotype. We present initial analyses of the human 4DN, capturing genome-wide structure using chromosome conformation capture and 3D imaging, and function using RNA-sequencing. We introduce a quantitative index that measures underlying topological stability of a genomic region. Our results show that structural features of genomic regions correlate with function with surprising persistence over time. Furthermore, constructing genome-wide gene-level contact maps aided in identifying gene pairs with high potential for coregulation and colocalization in a manner consistent with expression via transcription factories. We additionally use 2D phase planes to visualize patterns in 4DN data. Finally, we evaluated gene pairs within a circadian gene module using 3D imaging, and found periodicity in the movement of clock circadian regulator and period circadian clock 2 relative to each other that followed a circadian rhythm and entrained with their expression. PMID:26080430

  11. Atlas construction for dynamic (4D) PET using diffeomorphic transformations.

    PubMed

    Bieth, Marie; Lombaert, Hervé; Reader, Andrew J; Siddiqi, Kaleem

    2013-01-01

    A novel dynamic (4D) PET to PET image registration procedure is proposed and applied to multiple PET scans acquired with the high resolution research tomograph (HRRT), the highest resolution human brain PET scanner available in the world. By extending the recent diffeomorphic log-demons (DLD) method and applying it to multiple dynamic [11C]raclopride scans from the HRRT, an important step towards construction of a PET atlas of unprecedented quality for [11C]raclopride imaging of the human brain has been achieved. Accounting for the temporal dimension in PET data improves registration accuracy when compared to registration of 3D to 3D time-averaged PET images. The DLD approach was chosen for its ease in providing both an intensity and shape template, through iterative sequential pair-wise registrations with fast convergence. The proposed method is applicable to any PET radiotracer, providing 4D atlases with useful applications in high accuracy PET data simulations and automated PET image analysis. PMID:24579121

  12. 488-4D ASH LANDFILL CLOSURE CAP HELP MODELING

    SciTech Connect

    Phifer, M.

    2014-11-17

    At the request of Area Completion Projects (ACP) in support of the 488-4D Landfill closure, the Savannah River National Laboratory (SRNL) has performed Hydrologic Evaluation of Landfill Performance (HELP) modeling of the planned 488-4D Ash Landfill closure cap to ensure that the South Carolina Department of Health and Environmental Control (SCDHEC) limit of no more than 12 inches of head on top of the barrier layer (saturated hydraulic conductivity of no more than 1.0E-05 cm/s) in association with a 25-year, 24-hour storm event is not projected to be exceeded. Based upon Weber 1998 a 25-year, 24-hour storm event at the Savannah River Site (SRS) is 6.1 inches. The results of the HELP modeling indicate that the greatest peak daily head on top of the barrier layer (i.e. geosynthetic clay liner (GCL) or high density polyethylene (HDPE) geomembrane) for any of the runs made was 0.079 inches associated with a peak daily precipitation of 6.16 inches. This is well below the SCDHEC limit of 12 inches.

  13. 4D Dynamic Required Navigation Performance Final Report

    NASA Technical Reports Server (NTRS)

    Finkelsztein, Daniel M.; Sturdy, James L.; Alaverdi, Omeed; Hochwarth, Joachim K.

    2011-01-01

    New advanced four dimensional trajectory (4DT) procedures under consideration for the Next Generation Air Transportation System (NextGen) require an aircraft to precisely navigate relative to a moving reference such as another aircraft. Examples are Self-Separation for enroute operations and Interval Management for in-trail and merging operations. The current construct of Required Navigation Performance (RNP), defined for fixed-reference-frame navigation, is not sufficiently specified to be applicable to defining performance levels of such air-to-air procedures. An extension of RNP to air-to-air navigation would enable these advanced procedures to be implemented with a specified level of performance. The objective of this research effort was to propose new 4D Dynamic RNP constructs that account for the dynamic spatial and temporal nature of Interval Management and Self-Separation, develop mathematical models of the Dynamic RNP constructs, "Required Self-Separation Performance" and "Required Interval Management Performance," and to analyze the performance characteristics of these air-to-air procedures using the newly developed models. This final report summarizes the activities led by Raytheon, in collaboration with GE Aviation and SAIC, and presents the results from this research effort to expand the RNP concept to a dynamic 4D frame of reference.

  14. Complete valvular heart apparatus model from 4D cardiac CT.

    PubMed

    Grbic, Sasa; Ionasec, Razvan; Vitanovski, Dime; Voigt, Ingmar; Wang, Yang; Georgescu, Bogdan; Navab, Nassir; Comaniciu, Dorin

    2012-07-01

    The cardiac valvular apparatus, composed of the aortic, mitral, pulmonary and tricuspid valves, is an essential part of the anatomical, functional and hemodynamic characteristics of the heart and the cardiovascular system as a whole. Valvular heart diseases often involve multiple dysfunctions and require joint assessment and therapy of the valves. In this paper, we propose a complete and modular patient-specific model of the cardiac valvular apparatus estimated from 4D cardiac CT data. A new constrained Multi-linear Shape Model (cMSM), conditioned by anatomical measurements, is introduced to represent the complex spatio-temporal variation of the heart valves. The cMSM is exploited within a learning-based framework to efficiently estimate the patient-specific valve parameters from cine images. Experiments on 64 4D cardiac CT studies demonstrate the performance and clinical potential of the proposed method. Our method enables automatic quantitative evaluation of the complete valvular apparatus based on non-invasive imaging techniques. In conjunction with existent patient-specific chamber models, the presented valvular model enables personalized computation modeling and realistic simulation of the entire cardiac system.

  15. A technique for estimating 4D-CBCT using prior knowledge and limited-angle projections

    SciTech Connect

    Zhang, You; Yin, Fang-Fang; Ren, Lei; Segars, W. Paul

    2013-12-15

    Purpose: To develop a technique to estimate onboard 4D-CBCT using prior information and limited-angle projections for potential 4D target verification of lung radiotherapy.Methods: Each phase of onboard 4D-CBCT is considered as a deformation from one selected phase (prior volume) of the planning 4D-CT. The deformation field maps (DFMs) are solved using a motion modeling and free-form deformation (MM-FD) technique. In the MM-FD technique, the DFMs are estimated using a motion model which is extracted from planning 4D-CT based on principal component analysis (PCA). The motion model parameters are optimized by matching the digitally reconstructed radiographs of the deformed volumes to the limited-angle onboard projections (data fidelity constraint). Afterward, the estimated DFMs are fine-tuned using a FD model based on data fidelity constraint and deformation energy minimization. The 4D digital extended-cardiac-torso phantom was used to evaluate the MM-FD technique. A lung patient with a 30 mm diameter lesion was simulated with various anatomical and respirational changes from planning 4D-CT to onboard volume, including changes of respiration amplitude, lesion size and lesion average-position, and phase shift between lesion and body respiratory cycle. The lesions were contoured in both the estimated and “ground-truth” onboard 4D-CBCT for comparison. 3D volume percentage-difference (VPD) and center-of-mass shift (COMS) were calculated to evaluate the estimation accuracy of three techniques: MM-FD, MM-only, and FD-only. Different onboard projection acquisition scenarios and projection noise levels were simulated to investigate their effects on the estimation accuracy.Results: For all simulated patient and projection acquisition scenarios, the mean VPD (±S.D.)/COMS (±S.D.) between lesions in prior images and “ground-truth” onboard images were 136.11% (±42.76%)/15.5 mm (±3.9 mm). Using orthogonal-view 15°-each scan angle, the mean VPD/COMS between the lesion

  16. Comparison of an alternative and existing binning methods to reduce the acquisition duration of 4D PET/CT

    SciTech Connect

    Didierlaurent, David Ribes, Sophie; Caselles, Olivier; Jaudet, Cyril; Dierickx, Lawrence O.; Zerdoud, Slimane; Brillouet, Severine; Weits, Kathleen; Batatia, Hadj; Courbon, Frédéric

    2014-11-01

    than three bins were necessary for a more accurate measurement of the maximum amplitude of the tumor motion. However, the current 4D-CT technology limits the increase of the number of bins in 4D PET/CT because of missing CT slices. One can reconstruct 4D PET images with more bins but without attenuation/scatter correction.

  17. Evaluation of intrinsic respiratory signal determination methods for 4D CBCT adapted for mice

    SciTech Connect

    Martin, Rachael; Pan, Tinsu; Rubinstein, Ashley; Court, Laurence; Ahmad, Moiz

    2015-01-15

    Purpose: 4D CT imaging in mice is important in a variety of areas including studies of lung function and tumor motion. A necessary step in 4D imaging is obtaining a respiratory signal, which can be done through an external system or intrinsically through the projection images. A number of methods have been developed that can successfully determine the respiratory signal from cone-beam projection images of humans, however only a few have been utilized in a preclinical setting and most of these rely on step-and-shoot style imaging. The purpose of this work is to assess and make adaptions of several successful methods developed for humans for an image-guided preclinical radiation therapy system. Methods: Respiratory signals were determined from the projection images of free-breathing mice scanned on the X-RAD system using four methods: the so-called Amsterdam shroud method, a method based on the phase of the Fourier transform, a pixel intensity method, and a center of mass method. The Amsterdam shroud method was modified so the sharp inspiration peaks associated with anesthetized mouse breathing could be detected. Respiratory signals were used to sort projections into phase bins and 4D images were reconstructed. Error and standard deviation in the assignment of phase bins for the four methods compared to a manual method considered to be ground truth were calculated for a range of region of interest (ROI) sizes. Qualitative comparisons were additionally made between the 4D images obtained using each of the methods and the manual method. Results: 4D images were successfully created for all mice with each of the respiratory signal extraction methods. Only minimal qualitative differences were noted between each of the methods and the manual method. The average error (and standard deviation) in phase bin assignment was 0.24 ± 0.08 (0.49 ± 0.11) phase bins for the Fourier transform method, 0.09 ± 0.03 (0.31 ± 0.08) phase bins for the modified Amsterdam shroud method, 0

  18. 4D XCAT phantom for multimodality imaging research

    SciTech Connect

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-09-15

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ''Basic anatomical and physiological data for use in radiological protection: reference values,'' ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  19. 4D Light Field Imaging System Using Programmable Aperture

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam

    2012-01-01

    Complete depth information can be extracted from analyzing all angles of light rays emanated from a source. However, this angular information is lost in a typical 2D imaging system. In order to record this information, a standard stereo imaging system uses two cameras to obtain information from two view angles. Sometimes, more cameras are used to obtain information from more angles. However, a 4D light field imaging technique can achieve this multiple-camera effect through a single-lens camera. Two methods are available for this: one using a microlens array, and the other using a moving aperture. The moving-aperture method can obtain more complete stereo information. The existing literature suggests a modified liquid crystal panel [LC (liquid crystal) panel, similar to ones commonly used in the display industry] to achieve a moving aperture. However, LC panels cannot withstand harsh environments and are not qualified for spaceflight. In this regard, different hardware is proposed for the moving aperture. A digital micromirror device (DMD) will replace the liquid crystal. This will be qualified for harsh environments for the 4D light field imaging. This will enable an imager to record near-complete stereo information. The approach to building a proof-ofconcept is using existing, or slightly modified, off-the-shelf components. An SLR (single-lens reflex) lens system, which typically has a large aperture for fast imaging, will be modified. The lens system will be arranged so that DMD can be integrated. The shape of aperture will be programmed for single-viewpoint imaging, multiple-viewpoint imaging, and coded aperture imaging. The novelty lies in using a DMD instead of a LC panel to move the apertures for 4D light field imaging. The DMD uses reflecting mirrors, so any light transmission lost (which would be expected from the LC panel) will be minimal. Also, the MEMS-based DMD can withstand higher temperature and pressure fluctuation than a LC panel can. Robotics need

  20. 4D XCAT phantom for multimodality imaging research

    PubMed Central

    Segars, W. P.; Sturgeon, G.; Mendonca, S.; Grimes, Jason; Tsui, B. M. W.

    2010-01-01

    Purpose: The authors develop the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. Methods: Highly detailed whole-body anatomies for the adult male and female were defined in the XCAT using nonuniform rational B-spline (NURBS) and subdivision surfaces based on segmentation of the Visible Male and Female anatomical datasets from the National Library of Medicine as well as patient datasets. Using the flexibility of these surfaces, the Visible Human anatomies were transformed to match body measurements and organ volumes for a 50th percentile (height and weight) male and female. The desired body measurements for the models were obtained using the PEOPLESIZE program that contains anthropometric dimensions categorized from 1st to the 99th percentile for US adults. The desired organ volumes were determined from ICRP Publication 89 [ICRP, ‘‘Basic anatomical and physiological data for use in radiological protection: reference values,” ICRP Publication 89 (International Commission on Radiological Protection, New York, NY, 2002)]. The male and female anatomies serve as standard templates upon which anatomical variations may be modeled in the XCAT through user-defined parameters. Parametrized models for the cardiac and respiratory motions were also incorporated into the XCAT based on high-resolution cardiac- and respiratory-gated multislice CT data. To demonstrate the usefulness of the phantom, the authors show example simulation studies in PET, SPECT, and CT using publicly available simulation packages. Results: As demonstrated in the pilot studies, the 4D XCAT (which includes thousands of anatomical structures) can produce realistic imaging data when combined with accurate models of the imaging process. With the flexibility of the NURBS surface primitives, any number of different anatomies, cardiac or respiratory motions or patterns, and spatial resolutions can be simulated to perform imaging research. Conclusions: With the ability to produce

  1. Semaphorin 4D Contributes to Rheumatoid Arthritis by Inducing Inflammatory Cytokine Production: Pathogenic and Therapeutic Implications

    PubMed Central

    Yoshida, Yuji; Kang, Sujin; Ebina, Kousuke; Shi, Kenrin; Nojima, Satoshi; Kimura, Tetsuya; Ito, Daisuke; Morimoto, Keiko; Nishide, Masayuki; Hosokawa, Takashi; Hirano, Toru; Shima, Yoshihito; Narazaki, Masashi; Tsuboi, Hideki; Saeki, Yukihiko; Tomita, Tetsuya; Tanaka, Toshio; Kumanogoh, Atsushi

    2015-01-01

    Objective Semaphorin 4D (Sema4D)/CD100 has pleiotropic roles in immune activation, angiogenesis, bone metabolism, and neural development. We undertook this study to investigate the role of Sema4D in rheumatoid arthritis (RA). Methods Soluble Sema4D (sSema4D) levels in serum and synovial fluid were analyzed by enzyme‐linked immunosorbent assay. Cell surface expression and transcripts of Sema4D were analyzed in peripheral blood cells from RA patients, and immunohistochemical staining of Sema4D was performed in RA synovium. Generation of sSema4D was evaluated in an ADAMTS‐4–treated monocytic cell line (THP‐1 cells). The efficacy of anti‐Sema4D antibody was evaluated in mice with collagen‐induced arthritis (CIA). Results Levels of sSema4D were elevated in both serum and synovial fluid from RA patients, and disease activity markers were correlated with serum sSema4D levels. Sema4D‐expressing cells also accumulated in RA synovium. Cell surface levels of Sema4D on CD3+ and CD14+ cells from RA patients were reduced, although levels of Sema4D transcripts were unchanged. In addition, ADAMTS‐4 cleaved cell surface Sema4D to generate sSema4D in THP‐1 cells. Soluble Sema4D induced tumor necrosis factor α (TNFα) and interleukin‐6 (IL‐6) production from CD14+ monocytes. IL‐6 and TNFα induced ADAMTS‐4 expression in synovial cells. Treatment with an anti‐Sema4D antibody suppressed arthritis and reduced proinflammatory cytokine production in CIA. Conclusion A positive feedback loop involving sSema4D/IL‐6 and TNFα/ADAMTS‐4 may contribute to the pathogenesis of RA. The inhibition of arthritis by anti‐Sema4D antibody suggests that Sema4D represents a potential therapeutic target for RA. PMID:25707877

  2. Mapping motion from 4D-MRI to 3D-CT for use in 4D dose calculations: A technical feasibility study

    SciTech Connect

    Boye, Dirk; Lomax, Tony; Knopf, Antje

    2013-06-15

    Purpose: Target sites affected by organ motion require a time resolved (4D) dose calculation. Typical 4D dose calculations use 4D-CT as a basis. Unfortunately, 4D-CT images have the disadvantage of being a 'snap-shot' of the motion during acquisition and of assuming regularity of breathing. In addition, 4D-CT acquisitions involve a substantial additional dose burden to the patient making many, repeated 4D-CT acquisitions undesirable. Here the authors test the feasibility of an alternative approach to generate patient specific 4D-CT data sets. Methods: In this approach motion information is extracted from 4D-MRI. Simulated 4D-CT data sets [which the authors call 4D-CT(MRI)] are created by warping extracted deformation fields to a static 3D-CT data set. The employment of 4D-MRI sequences for this has the advantage that no assumptions on breathing regularity are made, irregularities in breathing can be studied and, if necessary, many repeat imaging studies (and consequently simulated 4D-CT data sets) can be performed on patients and/or volunteers. The accuracy of 4D-CT(MRI)s has been validated by 4D proton dose calculations. Our 4D dose algorithm takes into account displacements as well as deformations on the originating 4D-CT/4D-CT(MRI) by calculating the dose of each pencil beam based on an individual time stamp of when that pencil beam is applied. According to corresponding displacement and density-variation-maps the position and the water equivalent range of the dose grid points is adjusted at each time instance. Results: 4D dose distributions, using 4D-CT(MRI) data sets as input were compared to results based on a reference conventional 4D-CT data set capturing similar motion characteristics. Almost identical 4D dose distributions could be achieved, even though scanned proton beams are very sensitive to small differences in the patient geometry. In addition, 4D dose calculations have been performed on the same patient, but using 4D-CT(MRI) data sets based on

  3. Biomechanics of DNA structures visualized by 4D electron microscopy

    PubMed Central

    Lorenz, Ulrich J.; Zewail, Ahmed H.

    2013-01-01

    We present a technique for in situ visualization of the biomechanics of DNA structural networks using 4D electron microscopy. Vibrational oscillations of the DNA structure are excited mechanically through a short burst of substrate vibrations triggered by a laser pulse. Subsequently, the motion is probed with electron pulses to observe the impulse response of the specimen in space and time. From the frequency and amplitude of the observed oscillations, we determine the normal modes and eigenfrequencies of the structures involved. Moreover, by selective “nano-cutting” at a given point in the network, it was possible to obtain Young’s modulus, and hence the stiffness, of the DNA filament at that position. This experimental approach enables nanoscale mechanics studies of macromolecules and should find applications in other domains of biological networks such as origamis. PMID:23382239

  4. Myocardial motion and function assessment using 4D images

    NASA Astrophysics Data System (ADS)

    Shi, Peng-Cheng; Robinson, Glynn P.; Duncan, James S.

    1994-09-01

    This paper describes efforts aimed at more objectively and accurately quantifying the local, regional and global function of the left ventricle (LV) of the heart from 4D image data. Using our shape-based image analysis methods, point-wise myocardial motion vector fields between successive image frames through the entire cardiac cycle will be computed. Quantitative LV motion, thickening, and strain measurements will then be established from the point correspondence maps. In the paper, we will also briefly describe an in vivo experimental model which uses implanted imaging-opaque markers to validate the results of our image analysis methods. Finally, initial experimental results using image sequences from two different modalities will be presented.

  5. 4D GPR Experiments--Towards the Virtual Lysimeter

    NASA Astrophysics Data System (ADS)

    Grasmueck, M.; Viggiano, D. A.; Day-Lewis, F. D.; Drasdis, J. B.; Kruse, S. E.; Or, D.

    2006-05-01

    In-situ monitoring of infiltration, water flow and retention in the vadose zone currently rely primarily on invasive methods, which irreversibly disturb original soil structure and alter its hydrologic behavior in the vicinity of the measurement. For example, use of lysimeters requires extraction and repacking of soil samples, and time- domain reflectometry (TDR) requires insertion of probes into the soil profile. This study investigates the use of repeated high-density 3D ground penetrating radar surveys (also known as 4D GPR) as a non-invasive alternative for detailed visualization and quantification of water flow in the vadose zone. Evaluation of the 4D GPR method was based on a series of controlled point-source water injection experiments into undisturbed beach sand deposits at Crandon Park in Miami, Florida. The goal of the GPR surveys was to image the shape and evolution of a wet-bulb as it propagates from the injection points (~0.5 m) towards the water table at 2.2 m depth. The experimental design was guided by predictive modeling using Hydrus 2D and finite-difference GPR waveform codes. Input parameters for the modeling were derived from hydrologic and electromagnetic characterization of representative sand samples. Guided by modeling results, we injected 30 to 40 liters of tap water through plastic-cased boreholes with slotted bottom sections (0.1 m) located 0.4 to 0.6 m below the surface. During and after injection, an area of 25 m2 was surveyed every 20 minutes using 250 and 500 MHz antennas with a grid spacing of 0.05 x 0.025 m. A total of 20 3D GPR surveys were completed over 3 infiltration sites. To confirm wet-bulb shapes measured by GPR, we injected 2 liters of "brilliant blue" dye (~100 mg/l) along with a saline water tracer towards the end of one experiment. After completion of GPR scanning, a trench was excavated to examine the distribution of the saltwater and dye using TDR and visual inspection, respectively. Preliminary analysis of the 4D GPR

  6. Chaos in a 4D dissipative nonlinear fermionic model

    NASA Astrophysics Data System (ADS)

    Aydogmus, Fatma

    2015-12-01

    Gursey Model is the only possible 4D conformally invariant pure fermionic model with a nonlinear self-coupled spinor term. It has been assumed to be similar to the Heisenberg's nonlinear generalization of Dirac's equation, as a possible basis for a unitary description of elementary particles. Gursey Model admits particle-like solutions for the derived classical field equations and these solutions are instantonic in character. In this paper, the dynamical nature of damped and forced Gursey Nonlinear Differential Equations System (GNDES) are studied in order to get more information on spinor type instantons. Bifurcation and chaos in the system are observed by constructing the bifurcation diagrams and Poincaré sections. Lyapunov exponent and power spectrum graphs of GNDES are also constructed to characterize the chaotic behavior.

  7. 4D phase-space multiplexing for fluorescent microscopy

    NASA Astrophysics Data System (ADS)

    Liu, Hsiou-Yuan; Zhong, Jingshan; Waller, Laura

    2016-03-01

    Phase-space measurements enable characterization of second-order spatial coherence properties and can be used for digital aberration removal or 3D position reconstruction. Previous methods use a scanning aperture to measure the phase space spectrogram, which is slow and light inefficient, while also attenuating information about higher-order correlations. We demonstrate a significant improvement of speed and light throughput by incorporating multiplexing techniques into our phase-space imaging system. The scheme implements 2D coded aperture patterning in the Fourier (pupil) plane of a microscope using a Spatial Light Modulator (SLM), while capturing multiple intensity images in real space. We compare various multiplexing schemes to scanning apertures and show that our phase-space reconstructions are accurate for experimental data with biological samples containing many 3D fluorophores.

  8. Parallel Wavefront Analysis for a 4D Interferometer

    NASA Technical Reports Server (NTRS)

    Rao, Shanti R.

    2011-01-01

    This software provides a programming interface for automating data collection with a PhaseCam interferometer from 4D Technology, and distributing the image-processing algorithm across a cluster of general-purpose computers. Multiple instances of 4Sight (4D Technology s proprietary software) run on a networked cluster of computers. Each connects to a single server (the controller) and waits for instructions. The controller directs the interferometer to several images, then assigns each image to a different computer for processing. When the image processing is finished, the server directs one of the computers to collate and combine the processed images, saving the resulting measurement in a file on a disk. The available software captures approximately 100 images and analyzes them immediately. This software separates the capture and analysis processes, so that analysis can be done at a different time and faster by running the algorithm in parallel across several processors. The PhaseCam family of interferometers can measure an optical system in milliseconds, but it takes many seconds to process the data so that it is usable. In characterizing an adaptive optics system, like the next generation of astronomical observatories, thousands of measurements are required, and the processing time quickly becomes excessive. A programming interface distributes data processing for a PhaseCam interferometer across a Windows computing cluster. A scriptable controller program coordinates data acquisition from the interferometer, storage on networked hard disks, and parallel processing. Idle time of the interferometer is minimized. This architecture is implemented in Python and JavaScript, and may be altered to fit a customer s needs.

  9. Toward time resolved 4D cardiac CT imaging with patient dose reduction: estimating the global heart motion

    NASA Astrophysics Data System (ADS)

    Taguchi, Katsuyuki; Segars, W. Paul; Fung, George S. K.; Tsui, Benjamin M. W.

    2006-03-01

    Coronary artery imaging with multi-slice helical computed tomography is a promising noninvasive imaging technique. The current major issues include the insufficient temporal resolution and large patient dose. We propose an image reconstruction method which provides a solution to both of the problems. The method uses an iterative approach repeating the following four steps until the difference between the two projection data sets falls below a certain criteria in step-4: 1) estimating or updating the cardiac motion vectors, 2) reconstructing the time-resolved 4D dynamic volume images using the motion vectors, 3) calculating the projection data from the current 4D images, 4) comparing them with the measured ones. In this study, we obtain the first estimate of the motion vector. We use the 4D NCAT phantom, a realistic computer model for the human anatomy and cardiac motions, to generate the dynamic fan-beam projection data sets as well to provide a known truth for the motion. Then, the halfscan reconstruction with the sliding time-window technique is used to generate cine images: f(t, r r). Here, we use one heart beat for each position r so that the time information is retained. Next, the magnitude of the first derivative of f(t, r r) with respect to time, i.e., |df/dt|, is calculated and summed over a region-of-interest (ROI), which is called the mean-absolute difference (MAD). The initial estimation of the vector field are obtained using MAD for each ROI. Results of the preliminary study are presented.

  10. A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging

    NASA Astrophysics Data System (ADS)

    Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V.; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L.; Beauchemin, Steven S.; Rodrigues, George; Gaede, Stewart

    2015-02-01

    This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development.

  11. TU-F-12A-05: Sensitivity of Textural Features to 3D Vs. 4D FDG-PET/CT Imaging in NSCLC Patients

    SciTech Connect

    Yang, F; Nyflot, M; Bowen, S; Kinahan, P; Sandison, G

    2014-06-15

    Purpose: Neighborhood Gray-level difference matrices (NGLDM) based texture parameters extracted from conventional (3D) 18F-FDG PET scans in patients with NSCLC have been previously shown to associate with response to chemoradiation and poorer patient outcome. However, the change in these parameters when utilizing respiratory-correlated (4D) FDG-PET scans has not yet been characterized for NSCLC. The Objectives: of this study was to assess the extent to which NGLDM-based texture parameters on 4D PET images vary with reference to values derived from 3D scans in NSCLC. Methods: Eight patients with newly diagnosed NSCLC treated with concomitant chemoradiotherapy were included in this study. 4D PET scans were reconstructed with OSEM-IR in 5 respiratory phase-binned images and corresponding CT data of each phase were employed for attenuation correction. NGLDM-based texture features, consisting of coarseness, contrast, busyness, complexity and strength, were evaluated for gross tumor volumes defined on 3D/4D PET scans by radiation oncologists. Variation of the obtained texture parameters over the respiratory cycle were examined with respect to values extracted from 3D scans. Results: Differences between texture parameters derived from 4D scans at different respiratory phases and those extracted from 3D scans ranged from −30% to 13% for coarseness, −12% to 40% for contrast, −5% to 50% for busyness, −7% to 38% for complexity, and −43% to 20% for strength. Furthermore, no evident correlations were observed between respiratory phase and 4D scan texture parameters. Conclusion: Results of the current study showed that NGLDM-based texture parameters varied considerably based on choice of 3D PET and 4D PET reconstruction of NSCLC patient images, indicating that standardized image acquisition and analysis protocols need to be established for clinical studies, especially multicenter clinical trials, intending to validate prognostic values of texture features for NSCLC.

  12. Parallel Infrastructure Modeling and Inversion Module for E4D

    SciTech Connect

    2014-10-09

    Electrical resistivity tomography ERT is a method of imaging the electrical conductivity of the subsurface. Electrical conductivity is a useful metric for understanding the subsurface because it is governed by geomechanical and geochemical properties that drive subsurface systems. ERT works by injecting current into the subsurface across a pair of electrodes, and measuring the corresponding electrical potential response across another pair of electrodes. Many such measurements are strategically taken across an array of electrodes to produce an ERT data set. These data are then processed through a computationally demanding process known as inversion to produce an image of the subsurface conductivity structure that gave rise to the measurements. Data can be inverted to provide 2D images, 3D images, or in the case of time-lapse 3D imaging, 4D images. ERT is generally not well suited for environments with buried electrically conductive infrastructure such as pipes, tanks, or well casings, because these features tend to dominate and degrade ERT images. This reduces or eliminates the utility of ERT imaging where it would otherwise be highly useful for, for example, imaging fluid migration from leaking pipes, imaging soil contamination beneath leaking subusurface tanks, and monitoring contaminant migration in locations with dense network of metal cased monitoring wells. The location and dimension of buried metallic infrastructure is often known. If so, then the effects of the infrastructure can be explicitly modeled within the ERT imaging algorithm, and thereby removed from the corresponding ERT image. However,there are a number of obstacles limiting this application. 1) Metallic infrastructure cannot be accurately modeled with standard codes because of the large contrast in conductivity between the metal and host material. 2) Modeling infrastructure in true dimension requires the computational mesh to be highly refined near the metal inclusions, which increases

  13. 4D Dynamic RNP Annual Interim Report-Year 1

    NASA Technical Reports Server (NTRS)

    Finkelsztein, Daniel M.; Sturdy, James L.; Alaverdi, Omeed; Chung, William W.; Salvano, Daniel; Klooster, Joel; Hochwarth, Joachim K.

    2010-01-01

    This Annual Interim Report summarizes the activities led by Raytheon, in collaboration with GE Aviation and SAIC, and presents the results obtained during the first year of this research effort to expand the RNP concept to 4 dimensions relative to a dynamic frame of reference. Joint Program Development Office (JPDO)Concepts of Operations for the Next Generation Air Transportation System (NextGen) considers 4 Dimension Trajectory (4DT) procedures a key enabler to Trajectory Based Operations (TBO). The JPDO defines 4DT as a precise description of an aircraft path in space and time . While NextGen assumes that this path is defined within an Earth-reference frame, many 4DT procedure implementations will require an aircraft to precisely navigate relative to a moving reference such as another aircraft to form aggregate flows or a weather cell to allow for flows to shift. Current methods of implementing routes and flight paths rely on aircraft meeting a Required Navigation Performance (RNP) specification and being equipped with a monitoring and alerting capability to annunciate when the aircraft system is unable to meet the performance specification required for the operation. Since all aircraft today operate within the NAS relative to fixed reference points, the current RNP definition is deemed satisfactory. However, it is not well understood how the current RNP construct will support NextGen 4DT procedures where aircraft operate relative to each other or to other dynamic frames of reference. The objective of this research effort is to analyze candidate 4DT procedures from both an Air Navigation Service Provider (ANSP) and aircraft perspective, to identify their specific navigational requirements, assess the shortcomings of the current RNP construct to meet these requirements, to propose an extended 4 Dimensional Dynamic RNP (4D Dynamic RNP) construct that accounts for the dynamic spatial and temporal nature of the selected 4DT procedures, and finally, to design an

  14. Development of a dynamic 4D anthropomorphic breast phantom for contrast-based breast imaging

    NASA Astrophysics Data System (ADS)

    Kiarashi, Nooshin; Lin, Yuan; Segars, William P.; Ghate, Sujata V.; Ikejimba, Lynda; Chen, Baiyu; Lo, Joseph Y.; Dobbins, James T., III; Nolte, Loren W.; Samei, Ehsan

    2012-03-01

    Mammography is currently the most widely accepted tool for detection and diagnosis of breast cancer. However, the sensitivity of mammography is reduced in women with dense breast tissue due to tissue overlap, which may obscure lesions. Digital breast tomosynthesis with contrast enhancement reduces tissue overlap and provides additional functional information about lesions (i.e. morphology and kinetics), which in turn may improve lesion characterization. The performance of such techniques is highly dependent on the structural composition of the breast, which varies significantly across patients. Therefore, optimization of breast imaging systems should be done with respect to this patient versatility. Furthermore, imaging techniques that employ contrast require the inclusion of a temporally varying breast composition with respect to the contrast agent kinetics to enable the optimization of the system. To these ends, we have developed a dynamic 4D anthropomorphic breast phantom, which can be used for optimizing a breast imaging system by incorporating material characteristics. The presented dynamic phantom is based on two recently developed anthropomorphic breast phantoms, which can be representative of a whole population through their randomized anatomical feature generation and various compression levels. The 4D dynamic phantom is incorporated with the kinetics of contrast agent uptake in different tissues and can realistically model benign and malignant lesions. To demonstrate the utility of the proposed dynamic phantom, contrast-enhanced digital mammography and breast tomosynthesis were simulated where a ray-tracing algorithm emulated the projections, a filtered back projection algorithm was used for reconstruction, and dual-energy and temporal subtractions were performed and compared.

  15. Multimaterial 4D Printing with Tailorable Shape Memory Polymers.

    PubMed

    Ge, Qi; Sakhaei, Amir Hosein; Lee, Howon; Dunn, Conner K; Fang, Nicholas X; Dunn, Martin L

    2016-08-08

    We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures.

  16. Multimaterial 4D Printing with Tailorable Shape Memory Polymers

    NASA Astrophysics Data System (ADS)

    Ge, Qi; Sakhaei, Amir Hosein; Lee, Howon; Dunn, Conner K.; Fang, Nicholas X.; Dunn, Martin L.

    2016-08-01

    We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures.

  17. Multimaterial 4D Printing with Tailorable Shape Memory Polymers

    PubMed Central

    Ge, Qi; Sakhaei, Amir Hosein; Lee, Howon; Dunn, Conner K.; Fang, Nicholas X.; Dunn, Martin L.

    2016-01-01

    We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures. PMID:27499417

  18. Effortless assignment with 4D covariance sequential correlation maps.

    PubMed

    Harden, Bradley J; Mishra, Subrata H; Frueh, Dominique P

    2015-11-01

    Traditional Nuclear Magnetic Resonance (NMR) assignment procedures for proteins rely on preliminary peak-picking to identify and label NMR signals. However, such an approach has severe limitations when signals are erroneously labeled or completely neglected. The consequences are especially grave for proteins with substantial peak overlap, and mistakes can often thwart entire projects. To overcome these limitations, we previously introduced an assignment technique that bypasses traditional pick peaking altogether. Covariance Sequential Correlation Maps (COSCOMs) transform the indirect connectivity information provided by multiple 3D backbone spectra into direct (H, N) to (H, N) correlations. Here, we present an updated method that utilizes a single four-dimensional spectrum rather than a suite of three-dimensional spectra. We demonstrate the advantages of 4D-COSCOMs relative to their 3D counterparts. We introduce improvements accelerating their calculation. We discuss practical considerations affecting their quality. And finally we showcase their utility in the context of a 52 kDa cyclization domain from a non-ribosomal peptide synthetase.

  19. Multimaterial 4D Printing with Tailorable Shape Memory Polymers.

    PubMed

    Ge, Qi; Sakhaei, Amir Hosein; Lee, Howon; Dunn, Conner K; Fang, Nicholas X; Dunn, Martin L

    2016-01-01

    We present a new 4D printing approach that can create high resolution (up to a few microns), multimaterial shape memory polymer (SMP) architectures. The approach is based on high resolution projection microstereolithography (PμSL) and uses a family of photo-curable methacrylate based copolymer networks. We designed the constituents and compositions to exhibit desired thermomechanical behavior (including rubbery modulus, glass transition temperature and failure strain which is more than 300% and larger than any existing printable materials) to enable controlled shape memory behavior. We used a high resolution, high contrast digital micro display to ensure high resolution of photo-curing methacrylate based SMPs that requires higher exposure energy than more common acrylate based polymers. An automated material exchange process enables the manufacture of 3D composite architectures from multiple photo-curable SMPs. In order to understand the behavior of the 3D composite microarchitectures, we carry out high fidelity computational simulations of their complex nonlinear, time-dependent behavior and study important design considerations including local deformation, shape fixity and free recovery rate. Simulations are in good agreement with experiments for a series of single and multimaterial components and can be used to facilitate the design of SMP 3D structures. PMID:27499417

  20. Effortless assignment with 4D covariance sequential correlation maps

    NASA Astrophysics Data System (ADS)

    Harden, Bradley J.; Mishra, Subrata H.; Frueh, Dominique P.

    2015-11-01

    Traditional Nuclear Magnetic Resonance (NMR) assignment procedures for proteins rely on preliminary peak-picking to identify and label NMR signals. However, such an approach has severe limitations when signals are erroneously labeled or completely neglected. The consequences are especially grave for proteins with substantial peak overlap, and mistakes can often thwart entire projects. To overcome these limitations, we previously introduced an assignment technique that bypasses traditional pick peaking altogether. Covariance Sequential Correlation Maps (COSCOMs) transform the indirect connectivity information provided by multiple 3D backbone spectra into direct (H, N) to (H, N) correlations. Here, we present an updated method that utilizes a single four-dimensional spectrum rather than a suite of three-dimensional spectra. We demonstrate the advantages of 4D-COSCOMs relative to their 3D counterparts. We introduce improvements accelerating their calculation. We discuss practical considerations affecting their quality. And finally we showcase their utility in the context of a 52 kDa cyclization domain from a non-ribosomal peptide synthetase.

  1. 2,4-D and IAA Amino Acid Conjugates Show Distinct Metabolism in Arabidopsis

    PubMed Central

    Eyer, Luděk; Vain, Thomas; Pařízková, Barbora; Oklestkova, Jana; Barbez, Elke; Kozubíková, Hana; Pospíšil, Tomáš; Wierzbicka, Roksana; Kleine-Vehn, Jürgen; Fránek, Milan; Strnad, Miroslav; Robert, Stéphanie

    2016-01-01

    The herbicide 2,4-D exhibits an auxinic activity and therefore can be used as a synthetic and traceable analog to study auxin-related responses. Here we identified that not only exogenous 2,4-D but also its amide-linked metabolite 2,4-D-Glu displayed an inhibitory effect on plant growth via the TIR1/AFB auxin-mediated signaling pathway. To further investigate 2,4-D metabolite conversion, identity and activity, we have developed a novel purification procedure based on the combination of ion exchange and immuno-specific sorbents combined with a sensitive liquid chromatography-mass spectrometry method. In 2,4-D treated samples, 2,4-D-Glu and 2,4-D-Asp were detected at 100-fold lower concentrations compared to 2,4-D levels, showing that 2,4-D can be metabolized in the plant. Moreover, 2,4-D-Asp and 2,4-D-Glu were identified as reversible forms of 2,4-D homeostasis that can be converted to free 2,4-D. This work paves the way to new studies of auxin action in plant development. PMID:27434212

  2. 2,4-D and IAA Amino Acid Conjugates Show Distinct Metabolism in Arabidopsis.

    PubMed

    Eyer, Luděk; Vain, Thomas; Pařízková, Barbora; Oklestkova, Jana; Barbez, Elke; Kozubíková, Hana; Pospíšil, Tomáš; Wierzbicka, Roksana; Kleine-Vehn, Jürgen; Fránek, Milan; Strnad, Miroslav; Robert, Stéphanie; Novak, Ondrej

    2016-01-01

    The herbicide 2,4-D exhibits an auxinic activity and therefore can be used as a synthetic and traceable analog to study auxin-related responses. Here we identified that not only exogenous 2,4-D but also its amide-linked metabolite 2,4-D-Glu displayed an inhibitory effect on plant growth via the TIR1/AFB auxin-mediated signaling pathway. To further investigate 2,4-D metabolite conversion, identity and activity, we have developed a novel purification procedure based on the combination of ion exchange and immuno-specific sorbents combined with a sensitive liquid chromatography-mass spectrometry method. In 2,4-D treated samples, 2,4-D-Glu and 2,4-D-Asp were detected at 100-fold lower concentrations compared to 2,4-D levels, showing that 2,4-D can be metabolized in the plant. Moreover, 2,4-D-Asp and 2,4-D-Glu were identified as reversible forms of 2,4-D homeostasis that can be converted to free 2,4-D. This work paves the way to new studies of auxin action in plant development. PMID:27434212

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

    PubMed

    Manning, J T; Peters, M

    2009-09-01

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

  4. SU-E-J-26: A Novel Technique for Markerless Self-Sorted 4D-CBCT Using Patient Motion Modeling: A Feasibility Study

    SciTech Connect

    Zhang, L; Zhang, Y; Harris, W; Yin, F; Ren, L

    2015-06-15

    Purpose: To develop an automatic markerless 4D-CBCT projection sorting technique by using a patient respiratory motion model extracted from the planning 4D-CT images. Methods: Each phase of onboard 4D-CBCT is considered as a deformation of one phase of the prior planning 4D-CT. The deformation field map (DFM) is represented as a linear combination of three major deformation patterns extracted from the planning 4D-CT using principle component analysis (PCA). The coefficients of the PCA deformation patterns are solved by matching the digitally reconstructed radiograph (DRR) of the deformed volume to the onboard projection acquired. The PCA coefficients are solved for each single projection, and are used for phase sorting. Projections at the peaks of the Z direction coefficient are sorted as phase 1 and other projections are assigned into 10 phase bins by dividing phases equally between peaks. The 4D digital extended-cardiac-torso (XCAT) phantom was used to evaluate the proposed technique. Three scenarios were simulated, with different tumor motion amplitude (3cm to 2cm), tumor spatial shift (8mm SI), and tumor body motion phase shift (2 phases) from prior to on-board images. Projections were simulated over 180 degree scan-angle for the 4D-XCAT. The percentage of accurately binned projections across entire dataset was calculated to represent the phase sorting accuracy. Results: With a changed tumor motion amplitude from 3cm to 2cm, markerless phase sorting accuracy was 100%. With a tumor phase shift of 2 phases w.r.t. body motion, the phase sorting accuracy was 100%. With a tumor spatial shift of 8mm in SI direction, phase sorting accuracy was 86.1%. Conclusion: The XCAT phantom simulation results demonstrated that it is feasible to use prior knowledge and motion modeling technique to achieve markerless 4D-CBCT phase sorting. National Institutes of Health Grant No. R01-CA184173 Varian Medical System.

  5. 4D imaging of protein aggregation in live cells.

    PubMed

    Spokoini, Rachel; Shamir, Maya; Keness, Alma; Kaganovich, Daniel

    2013-01-01

    ubiquitinated are diverted to the IPOD, where they are actively aggregated in a protective compartment. Up until this point, the methodological paradigm of live-cell fluorescence microscopy has largely been to label proteins and track their locations in the cell at specific time-points and usually in two dimensions. As new technologies have begun to grant experimenters unprecedented access to the submicron scale in living cells, the dynamic architecture of the cytosol has come into view as a challenging new frontier for experimental characterization. We present a method for rapidly monitoring the 3D spatial distributions of multiple fluorescently labeled proteins in the yeast cytosol over time. 3D timelapse (4D imaging) is not merely a technical challenge; rather, it also facilitates a dramatic shift in the conceptual framework used to analyze cellular structure. We utilize a cytosolic folding sensor protein in live yeast to visualize distinct fates for misfolded proteins in cellular aggregation quality control, using rapid 4D fluorescent imaging. The temperature sensitive mutant of the Ubc9 protein (Ubc9(ts)) is extremely effective both as a sensor of cellular proteostasis, and a physiological model for tracking aggregation quality control. As with most ts proteins, Ubc9(ts) is fully folded and functional at permissive temperatures due to active cellular chaperones. Above 30 ° C, or when the cell faces misfolding stress, Ubc9(ts) misfolds and follows the fate of a native globular protein that has been misfolded due to mutation, heat denaturation, or oxidative damage. By fusing it to GFP or other fluorophores, it can be tracked in 3D as it forms Stress Foci, or is directed to JUNQ or IPOD. PMID:23608881

  6. GRAM 88 - 4D GLOBAL REFERENCE ATMOSPHERE MODEL-1988

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.

    1994-01-01

    the Jacchia values. Below 25km the atmospheric parameters are computed by the 4-D worldwide atmospheric model of Spiegler and Fowler (1972). This data set is not included. GRAM-88 incorporates a hydrostatic/gas law check in the 0-30 km altitude range to flag and change any bad data points. Between 5km and 30km, an interpolation scheme is used between the 4-D results and the modified Groves values. The output parameters consist of components for: (1) latitude, longitude, and altitude dependent monthly and annual means, (2) quasi-biennial oscillations (QBO), and (3) random perturbations to partially simulate the variability due to synoptic, diurnal, planetary wave, and gravity wave variations. Quasi-biennial and random variation perturbations are computed from parameters determined by various empirical studies and are added to the monthly mean values. The GRAM-88 program is for batch execution on the IBM 3084. It is written in STANDARD FORTRAN 77 under the MVS/XA operating system. The IBM DISPLA graphics routines are necessary for graphical output. The program was developed in 1988.

  7. A registration based approach for 4D cardiac micro-CT using combined prospective and retrospective gating

    PubMed Central

    Badea, Cristian T.; Schreibmann, Eduard; Fox, Tim

    2008-01-01

    Recent advances in murine cardiac studies with three-dimensional cone beam micro-computed tomography (CT) have used either prospective or retrospective gating technique. While prospective gating ensures the best image quality and the highest resolution, it involves longer sampling times and higher radiation dose. Sampling is faster and the radiation dose can be reduced with retrospective gating but the image quality is affected by the limited number of projections with an irregular angular distribution which complicate the reconstruction process, causing significant streaking artifacts. This work involves both prospective and retrospective gating in sampling. Deformable registration is used between a high quality image set acquired with prospective gating with the multiple data sets during the cardiac cycle obtained using retrospective gating. Tests were conducted on a four-dimensional (4D) cardiac mouse phantom and after optimization, the method was applied to in vivo cardiac micro-CT data. Results indicate that, by using our method, the sampling time can be reduced by a factor of 2.5 and the radiation dose can be reduced 35% compared to the prospective sampling while the image quality can be maintained. In conclusion, we proposed a novel solution to 4D cine cardiac micro-CT based on a combined prospective with retrospective gating in sampling and deformable registration post reconstruction that mixed the advantages of both strategies. PMID:18491508

  8. 4D measurement system for automatic location of anatomical structures

    NASA Astrophysics Data System (ADS)

    Witkowski, Marcin; Sitnik, Robert; Kujawińska, Małgorzata; Rapp, Walter; Kowalski, Marcin; Haex, Bart; Mooshake, Sven

    2006-04-01

    Orthopedics and neurosciences are fields of medicine where the analysis of objective movement parameters is extremely important for clinical diagnosis. Moreover, as there are significant differences between static and dynamic parameters, there is a strong need of analyzing the anatomical structures under functional conditions. In clinical gait analysis the benefits of kinematical methods are undoubted. In this paper we present a 4D (3D + time) measurement system capable of automatic location of selected anatomical structures by locating and tracing the structures' position and orientation in time. The presented system is designed to help a general practitioner in diagnosing selected lower limbs' dysfunctions (e.g. knee injuries) and also determine if a patient should be directed for further examination (e.g. x-ray or MRI). The measurement system components are hardware and software. For the hardware part we adapt the laser triangulation method. In this way we can evaluate functional and dynamic movements in a contact-free, non-invasive way, without the use of potentially harmful radiation. Furthermore, opposite to marker-based video-tracking systems, no preparation time is required. The software part consists of a data acquisition module, an image processing and point clouds (point cloud, set of points described by coordinates (x, y, z)) calculation module, a preliminary processing module, a feature-searching module and an external biomechanical module. The paper briefly presents the modules mentioned above with the focus on the feature-searching module. Also we present some measurement and analysis results. These include: parameters maps, landmarks trajectories in time sequence and animation of a simplified model of lower limbs.

  9. Infrared PINEM developed by diffraction in 4D UEM

    PubMed Central

    Liu, Haihua; Baskin, John Spencer; Zewail, Ahmed H.

    2016-01-01

    The development of four-dimensional ultrafast electron microscopy (4D UEM) has enabled not only observations of the ultrafast dynamics of photon–matter interactions at the atomic scale with ultrafast resolution in image, diffraction, and energy space, but photon–electron interactions in the field of nanoplasmonics and nanophotonics also have been captured by the related technique of photon-induced near-field electron microscopy (PINEM) in image and energy space. Here we report a further extension in the ongoing development of PINEM using a focused, nanometer-scale, electron beam in diffraction space for measurements of infrared-light-induced PINEM. The energy resolution in diffraction mode is unprecedented, reaching 0.63 eV under the 200-keV electron beam illumination, and separated peaks of the PINEM electron-energy spectrum induced by infrared light of wavelength 1,038 nm (photon energy 1.2 eV) have been well resolved for the first time, to our knowledge. In a comparison with excitation by green (519-nm) pulses, similar first-order PINEM peak amplitudes were obtained for optical fluence differing by a factor of more than 60 at the interface of copper metal and vacuum. Under high fluence, the nonlinear regime of IR PINEM was observed, and its spatial dependence was studied. In combination with PINEM temporal gating and low-fluence infrared excitation, the PINEM diffraction method paves the way for studies of structural dynamics in reciprocal space and energy space with high temporal resolution. PMID:26848135

  10. Binary 4D seismic history matching, a metric study

    NASA Astrophysics Data System (ADS)

    Chassagne, Romain; Obidegwu, Dennis; Dambrine, Julien; MacBeth, Colin

    2016-11-01

    This paper explores 4D seismic history matching and it specifically focuses on the objective function used during the optimisation with seismic data. The objective function is calculated by using binary maps, where one map is obtained from the observed seismic data and the other is from one realisation of the optimisation algorithm from the simulation model. In order to decide which set of parameters is a relevant update for the simulation model, an efficient way is required to measure how similar these two binary images are, during their evaluation within the objective function. Behind this aspect of quantification of the similarities or dissimilarities lies the metric notion, or the art of measuring distances. Four metrics are proposed with this study, the well-known Hamming distance, two widely used metrics, the Hausdorff distance and Mutual Information and a recent metric, called the Current Measure Metric. These metrics will be tested and compared on different case scenarios, designed in accordance to a real field case (gas exsolution) before being used in the second part of the paper. Despite its simplicity, the Hamming distance gives positive results, but the Current Measure Metric appears to be a more efficient choice to cover a wider range of scenarios, these conclusions remain true when tested on synthetic and real dataset in a history matching exercise. Some practical aspects of binary map processes will be examined through the paper, as it is shown that it is more proper to use a derivative free optimisation algorithm and a proper metric should be more inclined to capture global features than local features.

  11. Fast interactive exploration of 4D MRI flow data

    NASA Astrophysics Data System (ADS)

    Hennemuth, A.; Friman, O.; Schumann, C.; Bock, J.; Drexl, J.; Huellebrand, M.; Markl, M.; Peitgen, H.-O.

    2011-03-01

    1- or 2-directional MRI blood flow mapping sequences are an integral part of standard MR protocols for diagnosis and therapy control in heart diseases. Recent progress in rapid MRI has made it possible to acquire volumetric, 3-directional cine images in reasonable scan time. In addition to flow and velocity measurements relative to arbitrarily oriented image planes, the analysis of 3-dimensional trajectories enables the visualization of flow patterns, local features of flow trajectories or possible paths into specific regions. The anatomical and functional information allows for advanced hemodynamic analysis in different application areas like stroke risk assessment, congenital and acquired heart disease, aneurysms or abdominal collaterals and cranial blood flow. The complexity of the 4D MRI flow datasets and the flow related image analysis tasks makes the development of fast comprehensive data exploration software for advanced flow analysis a challenging task. Most existing tools address only individual aspects of the analysis pipeline such as pre-processing, quantification or visualization, or are difficult to use for clinicians. The goal of the presented work is to provide a software solution that supports the whole image analysis pipeline and enables data exploration with fast intuitive interaction and visualization methods. The implemented methods facilitate the segmentation and inspection of different vascular systems. Arbitrary 2- or 3-dimensional regions for quantitative analysis and particle tracing can be defined interactively. Synchronized views of animated 3D path lines, 2D velocity or flow overlays and flow curves offer a detailed insight into local hemodynamics. The application of the analysis pipeline is shown for 6 cases from clinical practice, illustrating the usefulness for different clinical questions. Initial user tests show that the software is intuitive to learn and even inexperienced users achieve good results within reasonable processing

  12. 32 CFR 1630.43 - Class 4-D: Minister of religion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Class 4-D: Minister of religion. 1630.43 Section... CLASSIFICATION RULES § 1630.43 Class 4-D: Minister of religion. In accord with part 1645 of this chapter any registrant shall be placed in Class 4-D who is a: (a) Duly ordained minister of religion; or (b)...

  13. 32 CFR 1630.43 - Class 4-D: Minister of religion.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Class 4-D: Minister of religion. 1630.43 Section... CLASSIFICATION RULES § 1630.43 Class 4-D: Minister of religion. In accord with part 1645 of this chapter any registrant shall be placed in Class 4-D who is a: (a) Duly ordained minister of religion; or (b)...

  14. 32 CFR 1630.43 - Class 4-D: Minister of religion.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Class 4-D: Minister of religion. 1630.43 Section... CLASSIFICATION RULES § 1630.43 Class 4-D: Minister of religion. In accord with part 1645 of this chapter any registrant shall be placed in Class 4-D who is a: (a) Duly ordained minister of religion; or (b)...

  15. 32 CFR 1630.43 - Class 4-D: Minister of religion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Class 4-D: Minister of religion. 1630.43 Section... CLASSIFICATION RULES § 1630.43 Class 4-D: Minister of religion. In accord with part 1645 of this chapter any registrant shall be placed in Class 4-D who is a: (a) Duly ordained minister of religion; or (b)...

  16. 32 CFR 1630.43 - Class 4-D: Minister of religion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Class 4-D: Minister of religion. 1630.43 Section... CLASSIFICATION RULES § 1630.43 Class 4-D: Minister of religion. In accord with part 1645 of this chapter any registrant shall be placed in Class 4-D who is a: (a) Duly ordained minister of religion; or (b)...

  17. 40 CFR 180.142 - 2,4-D; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false 2,4-D; tolerances for residues. 180..., plant regulator, and fungicide 2,4-D, including its metabolites and degradates, in or on the commodities... 2,4-D (2,4-dichlorophenoxyacetic acid), both free and conjugated, determined as the acid, in or...

  18. Mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) and mixtures of 2,4-D and 2,4,5-trichlorophenoxyacetic acid by Phanerochaete chrysosporium

    SciTech Connect

    Yadav, J.S.; Reddy, C.A. )

    1993-09-01

    2,4-dichloropheonxyacetic Acid (2,4-D) is one of the most commonly used phenoxyalkanoic herbicides for selective control of weeds and for defoliation. Since these toxic chemical are manufactured and used each year in massive quantities, effective handling of their production wastes and the contaminated environment is needed. A number of bacterial general are known to degrade 2,4-D, but no naturally occuring bacterium is know to be capable of mineralizing 2,4,5-trichlorophenoxyacetic acid. Mutual inhibition of degradation has been reported when 2,4-D and 2,4,5-T are presented in a mixture to degrading bacteria. This paper investigates the ability of Pseudomonas chrysosporium to mineralize 2,4-D individually and in combination with 2,4,5-T. Results indicate that P. chrysosporium effectively mineralizes 2,4-D alone as well as in combination with 2,4,5-T. 31 refs., 4 figs., 1 tab.

  19. SU-D-17A-04: The Impact of Audiovisual Biofeedback On Image Quality During 4D Functional and Anatomic Imaging: Results of a Prospective Clinical Trial

    SciTech Connect

    Keall, P; Pollock, S; Yang, J; Diehn, M; Berger, J; Graves, E; Loo, B; Yamamoto, T

    2014-06-01

    comprehension and capability. Supported by NIH/NCI R01 CA 093626, Stanford BioX Interdisciplinary Initiatives Program, NHMRC Australia Fellowship, and Kwanjeong Educational Foundation. GE Healthcare provided the Respiratory Gating Toolbox for 4D-PET image reconstruction. Stanford University owns US patent #E7955270 which is unlicensed to any commercial entity.

  20. Exceptional rigidity and biomechanics of amyloid revealed by 4D electron microscopy.

    PubMed

    Fitzpatrick, Anthony W P; Park, Sang Tae; Zewail, Ahmed H

    2013-07-01

    Amyloid is an important class of proteinaceous material because of its close association with protein misfolding disorders such as Alzheimer's disease and type II diabetes. Although the degree of stiffness of amyloid is critical to the understanding of its pathological and biological functions, current estimates of the rigidity of these β-sheet-rich protein aggregates range from soft (10(8) Pa) to hard (10(10) Pa) depending on the method used. Here, we use time-resolved 4D EM to directly and noninvasively measure the oscillatory dynamics of freestanding, self-supporting amyloid beams and their rigidity. The dynamics of a single structure, not an ensemble, were visualized in space and time by imaging in the microscope an amyloid-dye cocrystal that, upon excitation, converts light into mechanical work. From the oscillatory motion, together with tomographic reconstructions of three studied amyloid beams, we determined the Young modulus of these highly ordered, hydrogen-bonded β-sheet structures. We find that amyloid materials are very stiff (10(9) Pa). The potential biological relevance of the deposition of such a highly rigid biomaterial in vivo are discussed.

  1. Estimation of volcanic ash emissions from satellite data using trajectory-based 4D-Var

    NASA Astrophysics Data System (ADS)

    Lu, Sha; Lin, Haixiang; Heemink, Arnold; Segers, Arjo; Fu, Guangliang

    2016-04-01

    An accurate determination of emission parameters are crucial to the volcanic ash forecast for aviation, health and climate interests. In this study, we reconstruct the vertical profile of the volcanic ash emission from satellite ash mass loading data using trajectory-based 4D-Var (Trj4DVar) approach with Eyjafjallajökull 2010 eruptive event and the corresponding SEVIRI data as a study case. Since the Eyjafjallajökull eruption in April 2010, besides ash mass loadings retrieved from satellite data, the additional information of plume height and mass eruption rate is always available from volcanic ash detections and observations. Modifications is made in Trj4DVar to integrate the additional information into the data assimilation system to improve the estimation of volcanic ash emissions and achieve a better initial condition for quantitative predictions. The modified Trj4DVar has been tested in twin experiments designed based on the study case, and shows significant improvement on straightforward Trj4DVar since it has great correction impact to recognize the injection height and produce more accurate emission estimation and reliable initial field of volcanic ash loading. To apply the approach to the real case with SEVIRI data, two strategies was proposed: observational mask matrix and separate time windows. The results produced a better initial condition and predictive forecast that were more fitter the SEVIRI ash mass loading fields, which showed a great potential of applying the method in practice.

  2. Experimenting with the GMAO 4D Data Assimilation

    NASA Technical Reports Server (NTRS)

    Todling, R.; El Akkraoui, A.; Errico, R. M.; Guo, J.; Kim, J.; Kliest, D.; Parrish, D. F.; Suarez, M.; Trayanov, A.; Tremolet, Yannick; Whitaker, J.

    2012-01-01

    The Global Modeling and Assimilation Office (GMAO) has been working to promote its prototype four-dimensional variational (4DVAR) system to a version that can be exercised at operationally desirable configurations. Beyond a general circulation model (GeM) and an analysis system, traditional 4DV AR requires availability of tangent linear (TL) and adjoint (AD) models of the corresponding GeM. The GMAO prototype 4DVAR uses the finite-volume-based GEOS GeM and the Grid-point Statistical Interpolation (GSI) system for the first two, and TL and AD models derived ITom an early version of the finite-volume hydrodynamics that is scientifically equivalent to the present GEOS nonlinear GeM but computationally rather outdated. Specifically, the TL and AD models hydrodynamics uses a simple (I-dimensional) latitudinal MPI domain decomposition, which has consequent low scalability and prevents the prototype 4DV AR ITom being used in realistic applications. In the near future, GMAO will be upgrading its operational GEOS GCM (and assimilation system) to use a cubed-sphere-based hydrodynamics. This versions of the dynamics scales to thousands of processes and has led to a decision to re-derive the TL and AD models for this more modern dynamics, thus taking advantage of a two-dimensional MPI decomposition and improved scalability properties. With the aid of the Transformation of Algorithms in FORTRAN (l'AF) automatic adjoint generation tool and some hand-coding, a version of the cubed-sphere-based TL and AD models, with a simplified vertical diffusion scheme, is now available, enabling multiple configurations of standard implementations of 4DV AR in GEOS. Concurrent to this development, collaboration with the National Centers for Environmental Prediction (NCEP) and the Earth System Research Laboratory (ESRL) has allowed GMAO to implement a hybrid-ensemble capability within the GEOS data assimilation system. Both 3Dand 4D-ensemble capabilities are presently available thus allowing

  3. A dose error evaluation study for 4D dose calculations

    NASA Astrophysics Data System (ADS)

    Milz, Stefan; Wilkens, Jan J.; Ullrich, Wolfgang

    2014-10-01

    Previous studies have shown that respiration induced motion is not negligible for Stereotactic Body Radiation Therapy. The intrafractional breathing induced motion influences the delivered dose distribution on the underlying patient geometry such as the lung or the abdomen. If a static geometry is used, a planning process for these indications does not represent the entire dynamic process. The quality of a full 4D dose calculation approach depends on the dose coordinate transformation process between deformable geometries. This article provides an evaluation study that introduces an advanced method to verify the quality of numerical dose transformation generated by four different algorithms. The used transformation metric value is based on the deviation of the dose mass histogram (DMH) and the mean dose throughout dose transformation. The study compares the results of four algorithms. In general, two elementary approaches are used: dose mapping and energy transformation. Dose interpolation (DIM) and an advanced concept, so called divergent dose mapping model (dDMM), are used for dose mapping. The algorithms are compared to the basic energy transformation model (bETM) and the energy mass congruent mapping (EMCM). For evaluation 900 small sample regions of interest (ROI) are generated inside an exemplary lung geometry (4DCT). A homogeneous fluence distribution is assumed for dose calculation inside the ROIs. The dose transformations are performed with the four different algorithms. The study investigates the DMH-metric and the mean dose metric for different scenarios (voxel sizes: 8 mm, 4 mm, 2 mm, 1 mm 9 different breathing phases). dDMM achieves the best transformation accuracy in all measured test cases with 3-5% lower errors than the other models. The results of dDMM are reasonable and most efficient in this study, although the model is simple and easy to implement. The EMCM model also achieved suitable results, but the approach requires a more complex

  4. Interactive 4D Visualization of Sediment Transport Models

    NASA Astrophysics Data System (ADS)

    Butkiewicz, T.; Englert, C. M.

    2013-12-01

    Coastal sediment transport models simulate the effects that waves, currents, and tides have on near-shore bathymetry and features such as beaches and barrier islands. Understanding these dynamic processes is integral to the study of coastline stability, beach erosion, and environmental contamination. Furthermore, analyzing the results of these simulations is a critical task in the design, placement, and engineering of coastal structures such as seawalls, jetties, support pilings for wind turbines, etc. Despite the importance of these models, there is a lack of available visualization software that allows users to explore and perform analysis on these datasets in an intuitive and effective manner. Existing visualization interfaces for these datasets often present only one variable at a time, using two dimensional plan or cross-sectional views. These visual restrictions limit the ability to observe the contents in the proper overall context, both in spatial and multi-dimensional terms. To improve upon these limitations, we use 3D rendering and particle system based illustration techniques to show water column/flow data across all depths simultaneously. We can also encode multiple variables across different perceptual channels (color, texture, motion, etc.) to enrich surfaces with multi-dimensional information. Interactive tools are provided, which can be used to explore the dataset and find regions-of-interest for further investigation. Our visualization package provides an intuitive 4D (3D, time-varying) visualization of sediment transport model output. In addition, we are also integrating real world observations with the simulated data to support analysis of the impact from major sediment transport events. In particular, we have been focusing on the effects of Superstorm Sandy on the Redbird Artificial Reef Site, offshore of Delaware Bay. Based on our pre- and post-storm high-resolution sonar surveys, there has significant scour and bedform migration around the

  5. Ig-like transcript 4 as a cellular receptor for soluble complement fragment C4d.

    PubMed

    Hofer, Johannes; Forster, Florian; Isenman, David E; Wahrmann, Markus; Leitner, Judith; Hölzl, Markus A; Kovarik, Johannes J; Stockinger, Hannes; Böhmig, Georg A; Steinberger, Peter; Zlabinger, Gerhard J

    2016-04-01

    Complement regulation leads to the generation of complement split products (CSPs) such as complement component (C)4d, a marker for disease activity in autoimmune syndromes or antibody-mediated allograft rejection. However, the physiologic role of C4d has been unknown. By screening murine thymoma BW5147 cells expressing a cDNA library generated from human monocyte-derived dendritic cells with recombinant human C4d, we identified Ig-like transcript (ILT)4 and ILT5v2 as cellular receptors for C4d. Both receptors, expressed on monocytes, macrophages, and dendritic cells, also interacted with the CSPs C3d, C4b, C3b, and iC3b. However, C4d did not bind to classic complement receptors (CRs). Interaction between cell surface-resident ILT4 and soluble monomeric C4d resulted in endocytosis of C4d. Surprisingly, binding of soluble ILT4 to C4d covalently immobilized to a cellular surface following classic complement activation could not be detected. Remarkably, C4d immobilized to a solid phaseviaits intrinsic thioester conferred a dose-dependent inhibition of TNF-α and IL-6 secretion in monocytes activatedviaFc-cross-linking of up to 50% as compared to baseline. Similarly, C4d conferred an attenuation of intracellular Ca(2+)flux in monocytes activatedviaFc-cross-linking. In conclusion, ILT4 represents a scavenger-type endocytotic CR for soluble monomeric C4d, whereas attenuation of monocyte activation by physiologically oriented C4d on a surface appears to be dependent on a yet to be identified C4d receptor.-Hofer, J., Forster, F., Isenman, D. E., Wahrmann, M., Leitner, J., Hölzl, M. A., Kovarik, J. K., Stockinger, H., Böhmig, G. A., Steinberger, P., Zlabinger, G. J. Ig-like transcript 4 as a cellular receptor for soluble complement fragment C4d.

  6. Targeted disruption of the heat shock protein 20–phosphodiesterase 4D (PDE4D) interaction protects against pathological cardiac remodelling in a mouse model of hypertrophy

    PubMed Central

    Martin, Tamara P.; Hortigon-Vinagre, Maria P.; Findlay, Jane E.; Elliott, Christina; Currie, Susan; Baillie, George S.

    2014-01-01

    Phosphorylated heat shock protein 20 (HSP20) is cardioprotective. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and a mouse model of pressure overload mediated hypertrophy, we show that peptide disruption of the HSP20–phosphodiesterase 4D (PDE4D) complex results in attenuation of action potential prolongation and protection against adverse cardiac remodelling. The later was evidenced by improved contractility, decreased heart weight to body weight ratio, and reduced interstitial and perivascular fibrosis. This study demonstrates that disruption of the specific HSP20–PDE4D interaction leads to attenuation of pathological cardiac remodelling. PMID:25426411

  7. SEMA4D compromises blood-brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease.

    PubMed

    Smith, Ernest S; Jonason, Alan; Reilly, Christine; Veeraraghavan, Janaki; Fisher, Terrence; Doherty, Michael; Klimatcheva, Ekaterina; Mallow, Crystal; Cornelius, Chad; Leonard, John E; Marchi, Nicola; Janigro, Damir; Argaw, Azeb Tadesse; Pham, Trinh; Seils, Jennifer; Bussler, Holm; Torno, Sebold; Kirk, Renee; Howell, Alan; Evans, Elizabeth E; Paris, Mark; Bowers, William J; John, Gareth; Zauderer, Maurice

    2015-01-01

    Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood-brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit. PMID:25461192

  8. The Rab GTPase RabA4d regulates pollen tube tip growth in Arabidopsis thaliana.

    PubMed

    Szumlanski, Amy L; Nielsen, Erik

    2009-02-01

    During reproduction in flowering plants, pollen grains form a tube that grows in a polarized fashion through the female tissues to eventually fertilize the egg cell. These highly polarized pollen tubes have a rapid rate of growth that is supported by a tip-focused delivery of membrane and cell wall components. To gain a better understanding of how this growth is regulated, we investigated the function RABA4D, a member of the Arabidopsis thaliana RabA4 subfamily of Rab GTPase proteins. Here, we show that RABA4D was expressed in a pollen-specific manner and that enhanced yellow fluorescent protein (EYFP)-RabA4d-labeled membrane compartments localized to the tips of growing pollen tubes. Mutant pollen in which the RABA4D gene was disrupted displayed bulged pollen tubes with a reduced rate of growth in vitro and displayed altered deposition of some cell wall components. Expression of EYFP-RabA4d restored wild-type phenotypes to the raba4d mutant pollen tubes, while expression of EYFP-RabA4b did not rescue the raba4d phenotype. In vivo, disruption of RABA4D resulted in a male-specific transmission defect with mutant raba4d pollen tubes displaying aberrant growth in the ovary and reduced guidance at the micropyle. We propose that RabA4d plays an important role in the regulation of pollen tube tip growth.

  9. SEMA4D compromises blood-brain barrier, activates microglia, and inhibits remyelination in neurodegenerative disease.

    PubMed

    Smith, Ernest S; Jonason, Alan; Reilly, Christine; Veeraraghavan, Janaki; Fisher, Terrence; Doherty, Michael; Klimatcheva, Ekaterina; Mallow, Crystal; Cornelius, Chad; Leonard, John E; Marchi, Nicola; Janigro, Damir; Argaw, Azeb Tadesse; Pham, Trinh; Seils, Jennifer; Bussler, Holm; Torno, Sebold; Kirk, Renee; Howell, Alan; Evans, Elizabeth E; Paris, Mark; Bowers, William J; John, Gareth; Zauderer, Maurice

    2015-01-01

    Multiple sclerosis (MS) is a chronic neuroinflammatory disease characterized by immune cell infiltration of CNS, blood-brain barrier (BBB) breakdown, localized myelin destruction, and progressive neuronal degeneration. There exists a significant need to identify novel therapeutic targets and strategies that effectively and safely disrupt and even reverse disease pathophysiology. Signaling cascades initiated by semaphorin 4D (SEMA4D) induce glial activation, neuronal process collapse, inhibit migration and differentiation of oligodendrocyte precursor cells (OPCs), and disrupt endothelial tight junctions forming the BBB. To target SEMA4D, we generated a monoclonal antibody that recognizes mouse, rat, monkey and human SEMA4D with high affinity and blocks interaction between SEMA4D and its cognate receptors. In vitro, anti-SEMA4D reverses the inhibitory effects of recombinant SEMA4D on OPC survival and differentiation. In vivo, anti-SEMA4D significantly attenuates experimental autoimmune encephalomyelitis in multiple rodent models by preserving BBB integrity and axonal myelination and can be shown to promote migration of OPC to the site of lesions and improve myelin status following chemically-induced demyelination. Our study underscores SEMA4D as a key factor in CNS disease and supports the further development of antibody-based inhibition of SEMA4D as a novel therapeutic strategy for MS and other neurologic diseases with evidence of demyelination and/or compromise to the neurovascular unit.

  10. Digital in-line holography: 4-D imaging and tracking of micro-structures and organisms in microfluidics and biology

    NASA Astrophysics Data System (ADS)

    Garcia-Sucerquia, J.; Xu, W.; Jericho, S. K.; Jericho, M. H.; Tamblyn, I.; Kreuzer, H. J.

    2006-01-01

    In recent years, in-line holography as originally proposed by Gabor, supplemented with numerical reconstruction, has been perfected to the point at which wavelength resolution both laterally and in depth is routinely achieved with light by using digital in-line holographic microscopy (DIHM). The advantages of DIHM are: (1) simplicity of the hardware (laser- pinhole-CCD camera), (2) magnification is obtained in the numerical reconstruction, (3) maximum information of the 3-D structure with a depth of field of millimeters, (4) changes in the specimen and the simultaneous motion of many species, can be followed in 4-D at the camera frame rate. We present results obtained with DIHM in biological and microfluidic applications. By taking advantage of the large depth of field and the plane-to-plane reconstruction capability of DIHM, we can produce 3D representations of the paths followed by micron-sized objects such as suspensions of microspheres and biological samples (cells, algae, protozoa, bacteria). Examples from biology include a study of the motion of bacteria in a diatom and the track of algae and paramecium. In microfluidic applications we observe micro-channel flow, motion of bubbles in water and evolution in electrolysis. The paper finishes with new results from an underwater version of DIHM.

  11. The role of semaphorin 4D in tumor development and angiogenesis in human breast cancer

    PubMed Central

    Jiang, Hongchao; Chen, Ceshi; Sun, Qiangming; Wu, Jing; Qiu, Lijuan; Gao, Change; Liu, Weiqing; Yang, Jun; Jun, Nie; Dong, Jian

    2016-01-01

    Background Semaphorin 4D (Sema4D) is highly expressed in certain types of tumors and functions in the regulation of tumor angiogenesis and growth. However, it is still not clear regarding the roles of Sema4D in breast cancer. This study was designed to explore the effects of Sema4D on proliferation, cell cycle progression, apoptosis, invasion, migration, tumor growth, and angiogenesis in breast cancer. Materials and methods The expression level of Sema4D was investigated in MCF10A, 184A1, HCC1937, MDA-MB-468, MDA-MB-231, Hs578T, BT474, MCF-7, and T47D breast cancer cell lines by Western blotting analysis. Sema4D downregulation or overexpression was established by infection with lentiviruses-encoding Sema4D short hairpin RNA (shRNA) or Sema4D. To evaluate the effects of Sema4D on cell proliferation, cell cycle progression, apoptosis, invasion, and migration of MDA-MB-231 and MDA-MB-468 cells, methods including MTT assay, flow cytometry, wound healing assay, and transwell experiments were applied. BALB/c nude mice were injected with MDA-MB-231 cells, which were respectively infected with lentiviruses-encoding Sema4D, Sema4D shRNA, and GFP, followed by tumor angiogenesis assay. Results Sema4D was expressed at higher levels in breast cancer cell lines compared with the normal human breast epithelial cell lines, especially in MDA-MB-231 and MDA-MB-468 cells. Cell proliferation ability was remarkably inhibited in Sema4D downregulated condition, whereas the proportions of cells in the G0/G1 phase and apoptosis increased in MDA-MB-231 and MDA-MB-468 cells. In addition, the invasion and migration abilities of these cells were obviously reduced. Xenograft growth as well as angiogenesis was inhibited when infected with lentiviruses-encoding Sema4D shRNA in vivo. Conclusion Downregulation of Sema4D had notable influence on cell proliferation ability, invasion, migration, and apoptosis of both MDA-MB-231 and MDA-MB-468 cells. Furthermore, infection with lentiviruses

  12. IMRT treatment planning on 4D geometries for the era of dynamic MLC tracking.

    PubMed

    Suh, Yelin; Murray, Walter; Keall, Paul J

    2014-12-01

    The problem addressed here was to obtain optimal and deliverable dynamic multileaf collimator (MLC) leaf sequences from four-dimensional (4D) geometries for dynamic MLC tracking delivery. The envisaged scenario was where respiratory phase and position information of the target was available during treatment, from which the optimal treatment plan could be further adapted in real time. A tool for 4D treatment plan optimization was developed that integrates a commercially available treatment planning system and a general-purpose optimization system. The 4D planning method was applied to the 4D computed tomography planning scans of three lung cancer patients. The optimization variables were MLC leaf positions as a function of monitor units and respiratory phase. The objective function was the deformable dose-summed 4D treatment plan score. MLC leaf motion was constrained by the maximum leaf velocity between control points in terms of monitor units for tumor motion parallel to the leaf travel direction and between phases for tumor motion parallel to the leaf travel direction. For comparison and a starting point for the 4D optimization, three-dimensional (3D) optimization was performed on each of the phases. The output of the 4D IMRT planning process is a leaf sequence which is a function of both monitor unit and phase, which can be delivered to a patient whose breathing may vary between the imaging and treatment sessions. The 4D treatment plan score improved during 4D optimization by 34%, 4%, and 50% for Patients A, B, and C, respectively, indicating 4D optimization generated a better 4D treatment plan than the deformable sum of individually optimized phase plans. The dose-volume histograms for each phase remained similar, indicating robustness of the 4D treatment plan to respiratory variations expected during treatment delivery. In summary, 4D optimization for respiratory phase-dependent treatment planning with dynamic MLC motion tracking improved the 4D treatment plan

  13. 2D:4D digit ratio predicts delay of gratification in preschoolers.

    PubMed

    Da Silva, Sergio; Moreira, Bruno; Da Costa, Newton

    2014-01-01

    We replicate the Stanford marshmallow experiment with a sample of 141 preschoolers and find a correlation between lack of self-control and 2D:4D digit ratio. Children with low 2D:4D digit ratio are less likely to delay gratification. Low 2D:4D digit ratio may indicate high fetal testosterone. If this hypothesis is true, our finding means high fetal testosterone children are less likely to delay gratification.

  14. 2D:4D Digit Ratio Predicts Delay of Gratification in Preschoolers

    PubMed Central

    Da Silva, Sergio; Moreira, Bruno; Da Costa, Newton

    2014-01-01

    We replicate the Stanford marshmallow experiment with a sample of 141 preschoolers and find a correlation between lack of self-control and 2D:4D digit ratio. Children with low 2D:4D digit ratio are less likely to delay gratification. Low 2D:4D digit ratio may indicate high fetal testosterone. If this hypothesis is true, our finding means high fetal testosterone children are less likely to delay gratification. PMID:25490040

  15. Heterozygous mutations in cyclic AMP phosphodiesterase-4D (PDE4D) and protein kinase A (PKA) provide new insights into the molecular pathology of acrodysostosis.

    PubMed

    Kaname, Tadashi; Ki, Chang-Seok; Niikawa, Norio; Baillie, George S; Day, Jonathan P; Yamamura, Ken-Ichi; Ohta, Tohru; Nishimura, Gen; Mastuura, Nobuo; Kim, Ok-Hwa; Sohn, Young Bae; Kim, Hyun Woo; Cho, Sung Yoon; Ko, Ah-Ra; Lee, Jin Young; Kim, Hyun Wook; Ryu, Sung Ho; Rhee, Hwanseok; Yang, Kap-Seok; Joo, Keehyoung; Lee, Jooyoung; Kim, Chi Hwa; Cho, Kwang-Hyun; Kim, Dongsan; Yanagi, Kumiko; Naritomi, Kenji; Yoshiura, Ko-Ichiro; Kondoh, Tatsuro; Nii, Eiji; Tonoki, Hidefumi; Houslay, Miles D; Jin, Dong-Kyu

    2014-11-01

    Acrodysostosis without hormone resistance is a rare skeletal disorder characterized by brachydactyly, nasal hypoplasia, mental retardation and occasionally developmental delay. Recently, loss-of-function mutations in the gene encoding cAMP-hydrolyzing phosphodiesterase-4D (PDE4D) have been reported to cause this rare condition but the pathomechanism has not been fully elucidated. To understand the pathogenetic mechanism of PDE4D mutations, we conducted 3D modeling studies to predict changes in the binding efficacy of cAMP to the catalytic pocket in PDE4D mutants. Our results indicated diminished enzyme activity in the two mutants we analyzed (Gly673Asp and Ile678Thr; based on PDE4D4 residue numbering). Ectopic expression of PDE4D mutants in HEK293 cells demonstrated this reduction in activity, which was identified by increased cAMP levels. However, the cells from an acrodysostosis patient showed low cAMP accumulation, which resulted in a decrease in the phosphorylated cAMP Response Element-Binding Protein (pCREB)/CREB ratio. The reason for this discrepancy was due to a compensatory increase in expression levels of PDE4A and PDE4B isoforms, which accounted for the paradoxical decrease in cAMP levels in the patient cells expressing mutant isoforms with a lowered PDE4D activity. Skeletal radiographs of 10-week-old knockout (KO) rats showed that the distal part of the forelimb was shorter than in wild-type (WT) rats and that all the metacarpals and phalanges were also shorter in KO, as the name acrodysostosis implies. Like the G-protein α-stimulatory subunit and PRKAR1A, PDE4D critically regulates the cAMP signal transduction pathway and influences bone formation in a way that activity-compromising PDE4D mutations can result in skeletal dysplasia. We propose that specific inhibitory PDE4D mutations can lead to the molecular pathology of acrodysostosis without hormone resistance but that the pathological phenotype may well be dependent on an over-compensatory induction

  16. 4D VMAT, gated VMAT, and 3D VMAT for stereotactic body radiation therapy in lung.

    PubMed

    Chin, E; Loewen, S K; Nichol, A; Otto, K

    2013-02-21

    Four-dimensional volumetric modulated arc therapy (4D VMAT) is a treatment strategy for lung cancers that aims to exploit relative target and tissue motion to improve organ at risk (OAR) sparing. The algorithm incorporates the entire patient respiratory cycle using 4D CT data into the optimization process. Resulting treatment plans synchronize the delivery of each beam aperture to a specific phase of target motion. Stereotactic body radiation therapy treatment plans for 4D VMAT, gated VMAT, and 3D VMAT were generated on three patients with non-small cell lung cancer. Tumour motion ranged from 1.4-3.4 cm. The dose and fractionation scheme was 48 Gy in four fractions. A B-spline transformation model registered the 4D CT images. 4D dose volume histograms (4D DVH) were calculated from total dose accumulated at the maximum exhalation. For the majority of OARs, gated VMAT achieved the most radiation sparing but treatment times were 77-148% longer than 3D VMAT. 4D VMAT plan qualities were comparable to gated VMAT, but treatment times were only 11-25% longer than 3D VMAT. 4D VMAT's improvement of healthy tissue sparing can allow for further dose escalation. Future study could potentially adapt 4D VMAT to irregular patient breathing patterns.

  17. 4D VMAT, gated VMAT, and 3D VMAT for stereotactic body radiation therapy in lung

    NASA Astrophysics Data System (ADS)

    Chin, E.; Loewen, S. K.; Nichol, A.; Otto, K.

    2013-02-01

    Four-dimensional volumetric modulated arc therapy (4D VMAT) is a treatment strategy for lung cancers that aims to exploit relative target and tissue motion to improve organ at risk (OAR) sparing. The algorithm incorporates the entire patient respiratory cycle using 4D CT data into the optimization process. Resulting treatment plans synchronize the delivery of each beam aperture to a specific phase of target motion. Stereotactic body radiation therapy treatment plans for 4D VMAT, gated VMAT, and 3D VMAT were generated on three patients with non-small cell lung cancer. Tumour motion ranged from 1.4-3.4 cm. The dose and fractionation scheme was 48 Gy in four fractions. A B-spline transformation model registered the 4D CT images. 4D dose volume histograms (4D DVH) were calculated from total dose accumulated at the maximum exhalation. For the majority of OARs, gated VMAT achieved the most radiation sparing but treatment times were 77-148% longer than 3D VMAT. 4D VMAT plan qualities were comparable to gated VMAT, but treatment times were only 11-25% longer than 3D VMAT. 4D VMAT's improvement of healthy tissue sparing can allow for further dose escalation. Future study could potentially adapt 4D VMAT to irregular patient breathing patterns.

  18. Accelerated median root prior reconstruction for pinhole single-photon emission tomography (SPET)

    NASA Astrophysics Data System (ADS)

    Sohlberg, Antti; Ruotsalainen, Ulla; Watabe, Hiroshi; Iida, Hidehiro; Kuikka, Jyrki T.

    2003-07-01

    Pinhole collimation can be used to improve spatial resolution in SPET. However, the resolution improvement is achieved at the cost of reduced sensitivity, which leads to projection images with poor statistics. Images reconstructed from these projections using the maximum likelihood expectation maximization (ML-EM) algorithms, which have been used to reduce the artefacts generated by the filtered backprojection (FBP) based reconstruction, suffer from noise/bias trade-off: noise contaminates the images at high iteration numbers, whereas early abortion of the algorithm produces images that are excessively smooth and biased towards the initial estimate of the algorithm. To limit the noise accumulation we propose the use of the pinhole median root prior (PH-MRP) reconstruction algorithm. MRP is a Bayesian reconstruction method that has already been used in PET imaging and shown to possess good noise reduction and edge preservation properties. In this study the PH-MRP algorithm was accelerated with the ordered subsets (OS) procedure and compared to the FBP, OS-EM and conventional Bayesian reconstruction methods in terms of noise reduction, quantitative accuracy, edge preservation and visual quality. The results showed that the accelerated PH-MRP algorithm was very robust. It provided visually pleasing images with lower noise level than the FBP or OS-EM and with smaller bias and sharper edges than the conventional Bayesian methods.

  19. Validation of the 4D NCAT simulation tools for use in high-resolution x-ray CT research

    NASA Astrophysics Data System (ADS)

    Segars, W. P.; Mahesh, Mahadevappa; Beck, T.; Frey, E. C.; Tsui, B. M. W.

    2005-04-01

    We validate the computer-based simulation tools developed in our laboratory for use in high-resolution CT research. The 4D NURBS-based cardiac-torso (NCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and physiology. Unlike current phantoms in CT, the 4D NCAT has the advantage, due to its design, that its organ shapes can be changed to realistically model anatomical variations and patient motion. To efficiently simulate high-resolution CT images, we developed a unique analytic projection algorithm (including scatter and quantum noise) to accurately calculate projections directly from the surface definition of the phantom given parameters defining the CT scanner and geometry. The projection data are reconstructed into CT images using algorithms developed in our laboratory. The 4D NCAT phantom contains a level of detail that is close to impossible to produce in a physical test object. We, therefore, validate our CT simulation tools and methods through a series of direct comparisons with data obtained experimentally using existing, simple physical phantoms at different doses and using different x-ray energy spectra. In each case, the first-order simulations were found to produce comparable results (<12%). We reason that since the simulations produced equivalent results using simple test objects, they should be able to do the same in more anatomically realistic conditions. We conclude that, with the ability to provide realistic simulated CT image data close to that from actual patients, the simulation tools developed in this work will have applications in a broad range of CT imaging research.

  20. ECG and Navigator-Free 4D Whole-Heart Coronary MRA for Simultaneous Visualization of Cardiac Anatomy and Function

    PubMed Central

    Pang, Jianing; Sharif, Behzad; Fan, Zhaoyang; Bi, Xiaoming; Arsanjani, Reza; Berman, Daniel S.; Li, Debiao

    2014-01-01

    Purpose To develop a cardiac and respiratory self-gated 4D coronary MRA technique for simultaneous cardiac anatomy and function visualization. Methods A contrast-enhanced, ungated spoiled gradient echo sequence with self-gating (SG) and 3DPR trajectory was used for image acquisition. Data was retrospectively binned into different cardiac and respiratory phases based on information extracted from SG projections using principal component analysis. Each cardiac phase was reconstructed using a respiratory motion-corrected self-calibrating SENSE framework, and those belong to the quiescent period were retrospectively combined for coronary visualization. Healthy volunteer studies were conducted to evaluate the efficacy of the SG method, the accuracy of the left ventricle (LV) function parameters and the quality of coronary artery visualization. Results SG performed reliably for all subjects including one with poor ECG. The LV function parameters showed excellent agreement with those from a conventional cine protocol. For coronary imaging, the proposed method yielded comparable apparent SNR and coronary sharpness and lower apparent CNR on three subjects compared with an ECG and navigator-gated Cartesian protocol and an ECG-gated, respiratory motion-corrected 3DPR protocol. Conclusion A fully self-gated 4D whole-heart imaging technique was developed, potentially allowing cardiac anatomy and function assessment from a single measurement. PMID:25216287

  1. SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

    SciTech Connect

    Du, D; Mutic, S; Hu, Y; Caruthers, S; Glide-Hurst, C; Low, D

    2014-06-01

    Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquired separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation.

  2. Impact of CT attenuation correction method on quantitative respiratory-correlated (4D) PET/CT imaging

    SciTech Connect

    Nyflot, Matthew J.; Lee, Tzu-Cheng; Alessio, Adam M.; Kinahan, Paul E.; Wollenweber, Scott D.; Stearns, Charles W.; Bowen, Stephen R.

    2015-01-15

    Purpose: Respiratory-correlated positron emission tomography (PET/CT) 4D PET/CT is used to mitigate errors from respiratory motion; however, the optimal CT attenuation correction (CTAC) method for 4D PET/CT is unknown. The authors performed a phantom study to evaluate the quantitative performance of CTAC methods for 4D PET/CT in the ground truth setting. Methods: A programmable respiratory motion phantom with a custom movable insert designed to emulate a lung lesion and lung tissue was used for this study. The insert was driven by one of five waveforms: two sinusoidal waveforms or three patient-specific respiratory waveforms. 3DPET and 4DPET images of the phantom under motion were acquired and reconstructed with six CTAC methods: helical breath-hold (3DHEL), helical free-breathing (3DMOT), 4D phase-averaged (4DAVG), 4D maximum intensity projection (4DMIP), 4D phase-matched (4DMATCH), and 4D end-exhale (4DEXH) CTAC. Recovery of SUV{sub max}, SUV{sub mean}, SUV{sub peak}, and segmented tumor volume was evaluated as RC{sub max}, RC{sub mean}, RC{sub peak}, and RC{sub vol}, representing percent difference relative to the static ground truth case. Paired Wilcoxon tests and Kruskal–Wallis ANOVA were used to test for significant differences. Results: For 4DPET imaging, the maximum intensity projection CTAC produced significantly more accurate recovery coefficients than all other CTAC methods (p < 0.0001 over all metrics). Over all motion waveforms, ratios of 4DMIP CTAC recovery were 0.2 ± 5.4, −1.8 ± 6.5, −3.2 ± 5.0, and 3.0 ± 5.9 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. In comparison, recovery coefficients for phase-matched CTAC were −8.4 ± 5.3, −10.5 ± 6.2, −7.6 ± 5.0, and −13.0 ± 7.7 for RC{sub max}, RC{sub peak}, RC{sub mean}, and RC{sub vol}. When testing differences between phases over all CTAC methods and waveforms, end-exhale phases were significantly more accurate (p = 0.005). However, these differences were driven by

  3. Practical implementation of tetrahedral mesh reconstruction in emission tomography.

    PubMed

    Boutchko, R; Sitek, A; Gullberg, G T

    2013-05-01

    This paper presents a practical implementation of image reconstruction on tetrahedral meshes optimized for emission computed tomography with parallel beam geometry. Tetrahedral mesh built on a point cloud is a convenient image representation method, intrinsically three-dimensional and with a multi-level resolution property. Image intensities are defined at the mesh nodes and linearly interpolated inside each tetrahedron. For the given mesh geometry, the intensities can be computed directly from tomographic projections using iterative reconstruction algorithms with a system matrix calculated using an exact analytical formula. The mesh geometry is optimized for a specific patient using a two stage process. First, a noisy image is reconstructed on a finely-spaced uniform cloud. Then, the geometry of the representation is adaptively transformed through boundary-preserving node motion and elimination. Nodes are removed in constant intensity regions, merged along the boundaries, and moved in the direction of the mean local intensity gradient in order to provide higher node density in the boundary regions. Attenuation correction and detector geometric response are included in the system matrix. Once the mesh geometry is optimized, it is used to generate the final system matrix for ML-EM reconstruction of node intensities and for visualization of the reconstructed images. In dynamic PET or SPECT imaging, the system matrix generation procedure is performed using a quasi-static sinogram, generated by summing projection data from multiple time frames. This system matrix is then used to reconstruct the individual time frame projections. Performance of the new method is evaluated by reconstructing simulated projections of the NCAT phantom and the method is then applied to dynamic SPECT phantom and patient studies and to a dynamic microPET rat study. Tetrahedral mesh-based images are compared to the standard voxel-based reconstruction for both high and low signal-to-noise ratio

  4. Teaching Tip: Managing Software Engineering Student Teams Using Pellerin's 4-D System

    ERIC Educational Resources Information Center

    Doman, Marguerite; Besmer, Andrew; Olsen, Anne

    2015-01-01

    In this article, we discuss the use of Pellerin's Four Dimension Leadership System (4-D) as a way to manage teams in a classroom setting. Over a 5-year period, we used a modified version of the 4-D model to manage teams within a senior level Software Engineering capstone course. We found that this approach for team management in a classroom…

  5. Elite collegiate tennis athletes have lower 2D: 4D ratios than those of nonathlete controls.

    PubMed

    Hsu, Cheng-Chen; Su, Borcherng; Kan, Nai-Wen; Lai, Su-Ling; Fong, Tsorng-Harn; Chi, Chung-Pu; Chang, Ching-Chyuan; Hsu, Mei-Chich

    2015-03-01

    The ratio of the length of the second finger (index finger) to the fourth finger (ring finger) (2D:4D ratio) is a putative marker for prenatal hormones. Physiological research has suggested a low 2D:4D ratio correlates with high athletic ability. Athletes of specific sports (e.g., American football) have lower 2D:4D ratios than those of nonathletes, whereas athletes of some sports (e.g., rowing, gymnastics, and soccer) do not. This study investigated the 2D:4D ratios among collegiate tennis athletes, elite collegiate tennis athletes, and nonelite collegiate tennis athletes and compared them with nonathletes of both sexes. The participants included 43 elite collegiate tennis athletes (Level I intercollegiate athletes in Taiwan; 27 males and 16 females), 107 nonelite collegiate tennis athletes (Level II athletes; 55 males and 52 females), and 166 nonathlete college students (80 males and 86 females). The principle findings suggest that (a) regardless of sex, collegiate tennis athletes have lower 2D:4D values than those of nonathletes; (b) elite collegiate tennis athletes have lower 2D:4D values than those of nonathletes; (c) among females but not males, athletes and nonelite athletes have lower 2D:4D values than those of nonathletes; and (d) males have lower 2D:4D values than those of females. PMID:25226321

  6. Elite collegiate tennis athletes have lower 2D: 4D ratios than those of nonathlete controls.

    PubMed

    Hsu, Cheng-Chen; Su, Borcherng; Kan, Nai-Wen; Lai, Su-Ling; Fong, Tsorng-Harn; Chi, Chung-Pu; Chang, Ching-Chyuan; Hsu, Mei-Chich

    2015-03-01

    The ratio of the length of the second finger (index finger) to the fourth finger (ring finger) (2D:4D ratio) is a putative marker for prenatal hormones. Physiological research has suggested a low 2D:4D ratio correlates with high athletic ability. Athletes of specific sports (e.g., American football) have lower 2D:4D ratios than those of nonathletes, whereas athletes of some sports (e.g., rowing, gymnastics, and soccer) do not. This study investigated the 2D:4D ratios among collegiate tennis athletes, elite collegiate tennis athletes, and nonelite collegiate tennis athletes and compared them with nonathletes of both sexes. The participants included 43 elite collegiate tennis athletes (Level I intercollegiate athletes in Taiwan; 27 males and 16 females), 107 nonelite collegiate tennis athletes (Level II athletes; 55 males and 52 females), and 166 nonathlete college students (80 males and 86 females). The principle findings suggest that (a) regardless of sex, collegiate tennis athletes have lower 2D:4D values than those of nonathletes; (b) elite collegiate tennis athletes have lower 2D:4D values than those of nonathletes; (c) among females but not males, athletes and nonelite athletes have lower 2D:4D values than those of nonathletes; and (d) males have lower 2D:4D values than those of females.

  7. The Influence of Facial Characteristics on the Relation between Male 2D:4D and Dominance

    PubMed Central

    Ryckmans, Jan; Millet, Kobe; Warlop, Luk

    2015-01-01

    Although relations between 2D:4D and dominance rank in both baboons and rhesus macaques have been observed, evidence in humans is mixed. Whereas behavioral patterns in humans have been discovered that are consistent with these animal findings, the evidence for a relation between dominance and 2D:4D is weak or inconsistent. The present study provides experimental evidence that male 2D:4D is related to dominance after (fictitious) male-male interaction when the other man has a dominant, but not a submissive or neutral face. This finding provides evidence that the relationship between 2D:4D and dominance emerges in particular, predictable situations and that merely dominant facial characteristics of another person are enough to activate supposed relationships between 2D:4D and dominance. PMID:26600255

  8. Interpreting digit ratio (2D:4D)-behavior correlations: 2D:4D sex difference, stability, and behavioral correlates and their replicability in young children.

    PubMed

    Wong, Wang I; Hines, Melissa

    2016-02-01

    The popularity of using the ratio of the second to the fourth digit (2D:4D) to study influences of early androgen exposure on human behavior relies, in part, on a report that the ratio is sex-dimorphic and stable from age 2 years (Manning etal., 1998). However, subsequent research has rarely replicated this finding. Moreover, although 2D:4D has been correlated with many behaviors, these correlations are often inconsistent. Young children's 2D:4D-behavior correlations may be more consistent than those of older individuals, because young children have experienced fewer postnatal influences. To evaluate the usefulness of 2D:4D as a biomarker of prenatal androgen exposure in studies of 2D:4D-behavior correlations, we assessed its sex difference, temporal stability, and behavioral correlates over a 6- to 8-month period in 126, 2- to 3-year-old children, providing a rare same-sample replicability test. We found a moderate sex difference on both hands and high temporal stability. However, between-sex overlap and within-sex variability were also large. Only 3 of 24 correlations with sex-typed behaviors-scores on the Preschool Activities Inventory (PSAI), preference for a boy-typical toy, preference for a girl-typical toy, were significant and in the predicted direction, all of which involved the PSAI, partially confirming findings from another study. Correlation coefficients were larger for behaviors that showed larger sex differences. But, as in older samples, the overall pattern showed inconsistency across time, sex, and hand. Therefore, although sex-dimorphic and stable, 2D:4D-behavior correlations are no more consistent for young children than for older samples. Theoretical and methodological implications are discussed.

  9. Weight of the evidence on the human carcinogenicity of 2,4-D*

    PubMed Central

    Ibrahim, M. A.; Bond, G. G.; Burke, T. A.; Cole, P.; Dost, F. N.; Enterline, P. E.; Gough, M.; Greenberg, R. S.; Halperin, W. E.; McConnell, E.; Munro, I. C.; Swenberg, J. A.; Zahm, S. H.; Graham, J. D.

    1991-01-01

    The phenoxy herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used to control the growth of weeds and broadleaf plants. We convened a panel of 13 scientists to weigh the evidence on the human carcinogenicity of 2,4-D. The panel based its findings on a review of the toxicological and epidemiological literature on 2,4-D and related phenoxy herbicides. The toxicological data do not provide a strong basis for predicting that 2,4-D is a human carcinogen. Although a cause–effect relationship is far from being established, the epidemiological evidence for an association between exposure to 2,4-D and non–Hodgkin's lymphoma is suggestive and requires further investigation. There is little evidence of an association between use of 2,4-D and soft-tissue sarcoma or Hodgkin's disease, and no evidence of an association between 2,4-D use and any other form of cancer. Scientists on the panel were asked to categorize 2,4-D as a “known,” “probable,” “possible,” or “unlikely” carcinogen or as a noncarcinogen in humans. The predominant opinion among the panel members was that the weight of the evidence indicates that it is possible that exposure to 2,4-D can cause cancer in humans, although not all of the panelists believed the possibility was equally likely: one thought the possibility was strong, leaning toward probable, and five thought the possibility was remote, leaning toward unlikely. Two panelists believed it unlikely that 2,4-D can cause cancer in humans. PMID:1820267

  10. Serum Soluble Semaphorin 4D is Associated with Left Atrial Diameter in Patients with Atrial Fibrillation

    PubMed Central

    Xiang, Li; You, Tao; Chen, Jianchang; Xu, Weiting; Jiao, Yang

    2015-01-01

    Background The aim of this study was to evaluate the serum soluble semaphorin 4D (sSema4D) in patients with atrial fibrillation and to investigate the relationship of serum sSema4D with left atrial diameter (LAD). Material/Methods We studied a total of 113 patients who were subdivided into paroxysmal and non-paroxysmal (included persistent and permanent) atrial fibrillation groups, respectively. Another 55 subjects without atrial fibrillation were enrolled as the healthy control group. Serum levels of soluble semaphorin 4D (Sema4D) were measured in all subjects using the enzyme-labeled immunosorbent assay method. We also evaluated the coagulation parameters and left atrial diameters. Results Patients with paroxysmal and non-paroxysmal atrial fibrillation had significantly higher sSema4D level compared with controls (8.50±2.19 ng/mL and 9.30±2.28 ng/mL vs. 6.56±1.27 ng/ml, P<0.05). Serum sSema4D concentrations were elevated in patients with non-paroxysmal atrial fibrillation compared to those with paroxysmal atrial fibrillation (P<0.001). The level of sSema4D was positively correlated with LAD (r=0.606, P<0.001). Multivariate logistic regression analysis revealed that serum sSema4D, LAD, male sex, heart rate, hypertension, and coronary artery disease were associated with atrial fibrillation (P<0.05). Conclusions Serum sSema4D levels are increased in patients with atrial fibrillation and are independently associated with atrial remodeling. PMID:26417899

  11. TU-C-BRD-01: Image Guided SBRT I: Multi-Modality 4D Imaging

    SciTech Connect

    Cai, J; Mageras, G; Pan, T

    2014-06-15

    Motion management is one of the critical technical challenges for radiation therapy. 4D imaging has been rapidly adopted as essential tool to assess organ motion associated with respiratory breathing. A variety of 4D imaging techniques have been developed and are currently under development based on different imaging modalities such as CT, MRI, PET, and CBCT. Each modality provides specific and complementary information about organ and tumor respiratory motion. Effective use of each different technique or combined use of different techniques can introduce a comprehensive management of tumor motion. Specifically, these techniques have afforded tremendous opportunities to better define and delineate tumor volumes, more accurately perform patient positioning, and effectively apply highly conformal therapy techniques such as IMRT and SBRT. Successful implementation requires good understanding of not only each technique, including unique features, limitations, artifacts, imaging acquisition and process, but also how to systematically apply the information obtained from different imaging modalities using proper tools such as deformable image registration. Furthermore, it is important to understand the differences in the effects of breathing variation between different imaging modalities. A comprehensive motion management strategy using multi-modality 4D imaging has shown promise in improving patient care, but at the same time faces significant challenges. This session will focuses on the current status and advances in imaging respiration-induced organ motion with different imaging modalities: 4D-CT, 4D-MRI, 4D-PET, and 4D-CBCT/DTS. Learning Objectives: Understand the need and role of multimodality 4D imaging in radiation therapy. Understand the underlying physics behind each 4D imaging technique. Recognize the advantages and limitations of each 4D imaging technique.

  12. Development of Dynamic Spatial Video Camera (DSVC) for 4D observation, analysis and modeling of human body locomotion.

    PubMed

    Suzuki, Naoki; Hattori, Asaki; Hayashibe, Mitsuhiro; Suzuki, Shigeyuki; Otake, Yoshito

    2003-01-01

    We have developed an imaging system for free and quantitative observation of human locomotion in a time-spatial domain by way of real time imaging. The system is equipped with 60 computer controlled video cameras to film human locomotion from all angles simultaneously. Images are installed into the main graphic workstation and translated into a 2D image matrix. Observation of the subject from optional directions is able to be performed by selecting the view point from the optimum image sequence in this image matrix. This system also possesses a function to reconstruct 4D models of the subject's moving human body by using 60 images taken from all directions at one particular time. And this system also has the capability to visualize inner structures such as the skeletal or muscular systems of the subject by compositing computer graphics reconstructed from the MRI data set. We are planning to apply this imaging system to clinical observation in the area of orthopedics, rehabilitation and sports science.

  13. A non-uniformly sampled 4D HCC(CO)NH-TOCSY experiment processed using maximum entropy for rapid protein sidechain assignment

    PubMed Central

    Mobli, Mehdi; Stern, Alan S.; Bermel, Wolfgang; King, Glenn F.; Hoch, Jeffrey C.

    2010-01-01

    One of the stiffest challenges in structural studies of proteins using NMR is the assignment of sidechain resonances. Typically, a panel of lengthy 3D experiments are acquired in order to establish connectivities and resolve ambiguities due to overlap. We demonstrate that these experiments can be replaced by a single 4D experiment that is time-efficient, yields excellent resolution, and captures unique carbon-proton connectivity information. The approach is made practical by the use of non-uniform sampling in the three indirect time dimensions and maximum entropy reconstruction of the corresponding 3D frequency spectrum. This 4D method will facilitate automated resonance assignment procedures and it should be particularly beneficial for increasing throughput in NMR-based structural genomics initiatives. PMID:20299257

  14. A non-uniformly sampled 4D HCC(CO)NH-TOCSY experiment processed using maximum entropy for rapid protein sidechain assignment

    NASA Astrophysics Data System (ADS)

    Mobli, Mehdi; Stern, Alan S.; Bermel, Wolfgang; King, Glenn F.; Hoch, Jeffrey C.

    2010-05-01

    One of the stiffest challenges in structural studies of proteins using NMR is the assignment of sidechain resonances. Typically, a panel of lengthy 3D experiments are acquired in order to establish connectivities and resolve ambiguities due to overlap. We demonstrate that these experiments can be replaced by a single 4D experiment that is time-efficient, yields excellent resolution, and captures unique carbon-proton connectivity information. The approach is made practical by the use of non-uniform sampling in the three indirect time dimensions and maximum entropy reconstruction of the corresponding 3D frequency spectrum. This 4D method will facilitate automated resonance assignment procedures and it should be particularly beneficial for increasing throughput in NMR-based structural genomics initiatives.

  15. Four-dimensional (4D) PET/CT imaging of the thorax

    SciTech Connect

    Nehmeh, S.A.; Erdi, Y.E.; Pan, T.

    2004-12-01

    We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four lung cancer patients were monitored by tracking external markers placed on the thorax. A 4D-CT acquisition was performed using a 'step-and-shoot' technique, in which computed tomography (CT) projection data were acquired over a complete respiratory cycle at each couch position. The period of each CT acquisition segment was time stamped with an 'x-ray ON' signal, which was recorded by the tracking system. 4D-CT data were then sorted into 10 groups, according to their corresponding phase of the breathing cycle. 4D-PET data were acquired in the gated mode, where each breathing cycle was divided into ten 0.5 s bins. For both CT and PET acquisitions, patients received audio prompting to regularize breathing. The 4D-CT and 4D-PET data were then correlated according to respiratory phase. The effect of 4D acquisition on improving the co-registration of PET and CT images, reducing motion smearing, and consequently increase the quantitation of the SUV, were investigated. Also, quantitation of the tumor motions in PET, and CT, were studied and compared. 4D-PET with matching phase 4D-CTAC showed an improved accuracy in PET-CT image co-registration of up to 41%, compared to measurements from 4D-PET with clinical-CTAC. Gating PET data in correlation with respiratory motion reduced motion-induced smearing, thereby decreasing the observed tumor volume, by as much as 43%. 4D-PET lesions volumes showed a maximum deviation of 19% between clinical CT and phase- matched 4D-CT attenuation corrected PET images. In CT, 4D acquisition resulted in increasing the tumor volume in two patients by up to 79%, and decreasing it in the other two by up to 35%. Consequently, these

  16. Qualitative grading of aortic regurgitation: a pilot study comparing CMR 4D flow and echocardiography.

    PubMed

    Chelu, Raluca G; van den Bosch, Annemien E; van Kranenburg, Matthijs; Hsiao, Albert; van den Hoven, Allard T; Ouhlous, Mohamed; Budde, Ricardo P J; Beniest, Kirsten M; Swart, Laurens E; Coenen, Adriaan; Lubbers, Marisa M; Wielopolski, Piotr A; Vasanawala, Shreyas S; Roos-Hesselink, Jolien W; Nieman, Koen

    2016-02-01

    Over the past 10 years there has been intense research in the development of volumetric visualization of intracardiac flow by cardiac magnetic resonance (CMR).This volumetric time resolved technique called CMR 4D flow imaging has several advantages over standard CMR. It offers anatomical, functional and flow information in a single free-breathing, ten-minute acquisition. However, the data obtained is large and its processing requires dedicated software. We evaluated a cloud-based application package that combines volumetric data correction and visualization of CMR 4D flow data, and assessed its accuracy for the detection and grading of aortic valve regurgitation using transthoracic echocardiography as reference. Between June 2014 and January 2015, patients planned for clinical CMR were consecutively approached to undergo the supplementary CMR 4D flow acquisition. Fifty four patients(median age 39 years, 32 males) were included. Detection and grading of the aortic valve regurgitation using CMR4D flow imaging were evaluated against transthoracic echocardiography. The agreement between 4D flow CMR and transthoracic echocardiography for grading of aortic valve regurgitation was good (j = 0.73). To identify relevant,more than mild aortic valve regurgitation, CMR 4D flow imaging had a sensitivity of 100 % and specificity of 98 %. Aortic regurgitation can be well visualized, in a similar manner as transthoracic echocardiography, when using CMR 4D flow imaging. PMID:26498478

  17. 2,4-D resistance in wild radish: reduced herbicide translocation via inhibition of cellular transport

    PubMed Central

    Goggin, Danica E.; Cawthray, Gregory R.; Powles, Stephen B.

    2016-01-01

    Resistance to auxinic herbicides is increasing in a range of dicotyledonous weed species, but in most cases the biochemical mechanism of resistance is unknown. Using 14C-labelled herbicide, the mechanism of resistance to 2,4-dichlorophenoxyacetic acid (2,4-D) in two wild radish (Raphanus raphanistrum L.) populations was identified as an inability to translocate 2,4-D out of the treated leaf. Although 2,4-D was metabolized in wild radish, and in a different manner to the well-characterized crop species wheat and bean, there was no difference in metabolism between the susceptible and resistant populations. Reduced translocation of 2,4-D in the latter was also not due to sequestration of the herbicide, or to reduced uptake by the leaf epidermis or mesophyll cells. Application of auxin efflux or ABCB transporter inhibitors to 2,4-D-susceptible plants caused a mimicking of the reduced-translocation resistance phenotype, suggesting that 2,4-D resistance in the populations under investigation could be due to an alteration in the activity of a plasma membrane ABCB-type auxin transporter responsible for facilitating long-distance transport of 2,4-D. PMID:26994475

  18. Generation and preclinical characterization of an antibody specific for SEMA4D

    PubMed Central

    Fisher, Terrence L.; Reilly, Christine A.; Winter, Laurie A.; Pandina, Tracy; Jonason, Alan; Scrivens, Maria; Balch, Leslie; Bussler, Holm; Torno, Sebold; Seils, Jennifer; Mueller, Loretta; Huang, He; Klimatcheva, Ekaterina; Howell, Alan; Kirk, Renee; Evans, Elizabeth; Paris, Mark; Leonard, John E.; Smith, Ernest S.; Zauderer, Maurice

    2016-01-01

    Semaphorin 4D (SEMA4D or CD100) is a member of the semaphorin family of proteins and an important mediator of the movement and differentiation of multiple cell types, including those of the immune, vascular, and nervous systems. Blocking the binding of SEMA4D to its receptors can result in physiologic changes that may have implications in cancer, autoimmune, and neurological disease. To study the effects of blocking SEMA4D, we generated, in SEMA4D-deficient mice, a panel of SEMA4D-specific hybridomas that react with murine, primate, and human SEMA4D. Utilizing the complementarity-determining regions from one of these hybridomas (mAb 67-2), we generated VX15/2503, a humanized IgG4 monoclonal antibody that is currently in clinical development for the potential treatment of various malignancies and neurodegenerative disorders, including multiple sclerosis and Huntington's disease. This work describes the generation and characterization of VX15/2503, including in vitro functional testing, epitope mapping, and an in vivo demonstration of efficacy in an animal model of rheumatoid arthritis. PMID:26431358

  19. Fluorescent caged compounds of 2,4-dichlorophenoxyacetic acid (2,4-d): photorelease technology for controlled release of 2,4-D.

    PubMed

    Atta, Sanghamitra; Jana, Avijit; Ananthakirshnan, Rajakumar; Narayana Dhuleep, Pradeep Singh

    2010-11-24

    A novel controlled-release formulation (CRF) of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was developed to reduce its negative environmental impacts by improving its herbicidal efficacy. The 2,4-D was chemically caged by coupling with photoremovable protecting groups (PRPGs) of coumarin derivatives. Photophysical studies of caged compounds showed that they all exhibited strong fluorescence properties. Controlled release of 2,4-D was achieved by irradiating the caged compounds using UV-vis light (310, 350, and 410 nm). The effect of various factors such as pH, solvent, and different substituents at the seventh position of coumarin moiety on the rate of photorelease was studied. The herbicidal activity of caged compounds and 4-(hydroxymethyl)-7-substituted coumarins was studied against Vigna radiata . The new formulation provided greater control over the release of 2,4-D by UV-vis light and also demonstrated the potential of the PRPGs not only to act as a delivery device but also to possess herbicidal activity after photorelease.

  20. Bacterial degradation of phenoxy herbicide mixtures 2,4-D and MCPP

    SciTech Connect

    Kyeheon Oh; Tuovinen, O.H. )

    1991-08-01

    The phenoxy herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-(2-methyl-4-chlorophenoxy)propionic acid (MCPP) have auxin-like growth regulating properties and are extensively used for the control of broad-leaf angiosperm weeds. The microbiological degradation of 2,4-D by pure and mixed cultures has been examined in a number of studies. The authors have previously evaluated the concurrent microbiological degradation of 2,4-D and MCPP in stirred tank reactors. For the present paper, they examined the utilization of the two substrates by three mixed cultures that had a previous history of growth with the respective single phenoxy herbicide.

  1. SU-E-J-241: Creation of Ventilation CT From Daily 4D CTs Or 4D Conebeam CTs Acquired During IGRT for Thoracic Cancers

    SciTech Connect

    Tai, A; Ahunbay, E; Li, X

    2014-06-01

    Purpose: To develop a method to create ventilation CTs from daily 4D CTs or 4D KV conebeam CTs (4DCBCT) acquired during image-guided radiation therapy (IGRT) for thoracic tumors, and to explore the potential for using the ventilation CTs as a means for early detection of lung injury during radiation treatment. Methods: 4DCT acquired using an in-room CT (CTVision, Siemens) and 4DCBCT acquired using the X-ray Volume Imaging (XVI) system (Infinity, Elekta) for representative lung cancer patients were analyzed. These 4D data sets were sorted into 10 phase images. A newly-available deformable image registration tool (ADMIRE, Elekta) is used to deform the phase images at the end of exhale (EE) to the phase images at the end of inhale (EI). The lung volumes at EI and EE were carefully contoured using an intensity-based auto-contour tool and then manually edited. The ventilation images were calculated from the variations of CT numbers of those voxels masked by the lung contour at EI between the registered phase images. The deformable image registration is also performed between the daily 4D images and planning 4DCT, and the resulting deformable field vector (DFV) is used to deform the planning doses to the daily images by an in-house Matlab program. Results: The ventilation images were successfully created. The tide volumes calculated using the ventilation images agree with those measured through volume difference of contours at EE and EI, indicating the accuracy of ventilation images. The association between the delivered doses and the change of lung ventilation from the daily ventilation CTs is identified. Conclusions: A method to create the ventilation CT using daily 4DCTs or 4D KV conebeam CTs was developed and demonstrated.

  2. Measurement and Structural Model Class Separation in Mixture CFA: ML/EM versus MCMC

    ERIC Educational Resources Information Center

    Depaoli, Sarah

    2012-01-01

    Parameter recovery was assessed within mixture confirmatory factor analysis across multiple estimator conditions under different simulated levels of mixture class separation. Mixture class separation was defined in the measurement model (through factor loadings) and the structural model (through factor variances). Maximum likelihood (ML) via the…

  3. SU-E-J-240: Development of a Novel 4D MRI Sequence for Real-Time Liver Tumor Tracking During Radiotherapy

    SciTech Connect

    Zhuang, L; Burmeister, J; Ye, Y

    2015-06-15

    Purpose: To develop a Novel 4D MRI Technique that is feasible for realtime liver tumor tracking during radiotherapy. Methods: A volunteer underwent an abdominal 2D fast EPI coronal scan on a 3.0T MRI scanner (Siemens Inc., Germany). An optimal set of parameters was determined based on image quality and scan time. A total of 23 slices were scanned to cover the whole liver in the test scan. For each scan position, the 2D images were retrospectively sorted into multiple phases based on breathing signal extracted from the images. Consequently the 2D slices with same phase numbers were stacked to form one 3D image. Multiple phases of 3D images formed the 4D MRI sequence representing one breathing cycle. Results: The optimal set of scan parameters were: TR= 57ms, TE= 19ms, FOV read= 320mm and flip angle= 30°, which resulted in a total scan time of 14s for 200 frames (FMs) per slice and image resolution of (2.5mm,2.5mm,5.0mm) in three directions. Ten phases of 3D images were generated, each of which had 23 slices. Based on our test scan, only 100FMs were necessary for the phase sorting process which may lower the scan time to 7s/100FMs/slice. For example, only 5 slices/35s are necessary for a 4D MRI scan to cover liver tumor size ≤ 2cm leading to the possibility of tumor trajectory tracking every 35s during treatment. Conclusion: The novel 4D MRI technique we developed can reconstruct a 4D liver MRI sequence representing one breathing cycle (7s/ slice) without an external monitor. This technique can potentially be used for real-time liver tumor tracking during radiotherapy.

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

    PubMed Central

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

    2013-01-01

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

  5. Relation between the 4d superconformal index and the S 3 partition function

    NASA Astrophysics Data System (ADS)

    Imamura, Yosuke

    2011-09-01

    A relation between the 4d superconformal index and the S 3 partition function is studied with focus on the 4d and 3d actions used in localization. In the case of vanishing Chern-Simons levels and round S 3 we explicitly show that the 3d action is obtained from the4d action by dimensional reduction up to terms which do not affect the exact results. By combining this fact and a recent proposal concerning a squashing of S 3 and SU(2) Wilson line, we obtain a formula which gives the partition function depending on the Weyl weight of chiral multiplets, real mass parameters, FI parameters, and a squashing parameter as a limit of the index of a parent 4d theory.

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

    PubMed

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

    2013-01-01

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

  7. Dissipation and residue of 2,4-D in citrus under field condition.

    PubMed

    Chen, Weijun; Jiao, Bining; Su, Xuesu; Zhao, Qiyang; Sun, Dali

    2015-05-01

    The dissipation, residues, and risks of 2,4-dicholrophenoxyacetic acid (2,4-D) in citrus under field condition were investigated based on a simple ultra-performance LC (UPLC)-MS/MS method. The results indicated that the residue level of 2,4-D in citrus did not degrade gradually with sampling time under field condition. At pre-harvest intervals (PHI) of 20-40 days, 2,4-D residues were 0.021-0.269 mg/kg in citrus flesh, 0.028-0.337 mg/kg in whole citrus, and 0.028-0.376 mg/kg in citrus peel, all bellow the China maximum residue limit in citrus (1 mg/kg). Risks of 2,4-D were assessed by calculation of risk quotient, and the results revealed no significant health risks after consumption of citrus.

  8. Residues of 2, 4-D in air samples from Saskatchewan: 1966-1975.

    PubMed

    Grover, R; Kerr, L A; Wallace, K; Yoshida, K; Maybank, J

    1976-01-01

    Residues of 2,4-D (2,4-dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966-68 and 1970-75 periods were determined by gas-liquid chromatographic techniques. Initially, individual esters of 2,4-D were characterized by retention times and confirmed further by co-injection and dual column procedures. Since 1973, however, only total 2,4-D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible. Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4-D, with butyl esters being found most frequently. The daily 24-hr mean atmospheric concentrations of 2,4-D ranged from 0.01 to 1.22 mug/m3, 0.01 to 13.50 mug/m3, and 0.05 to 0.59 mug/m3 for the iso-propyl, mixed butyl and iso-octyl esters, respectively. Even when the samples were analysed for the total 2,4-D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 mug/m3. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 mug/m3 of 2,4-D. In another 40% of the samples, the levels of 2,4-D ranged from 0.01 to 0.099 mug/m3. Only about 30% of the samples contained 2,4-D concentrations higher than 0.1 mug/m3, with only 10% or less exceeding 1 mug/m3. None of the samples, obtained with the high volume particulate sampler, showed any detectable levels of 2,4-D, indicating little or no transport of 2,4-D adsorbed on dust particles or as crystals of amine salts. PMID:1002953

  9. Energy levels in Ag-like (4d{sup 10}4f, 4d{sup 10}5l (l = 0-3)), Pd-like (4d{sup 9}4f [J = 1], 4d{sup 9}5p [J = 1], 4d{sup 9}5f [J = 1]), and Rh-like (4d{sup 9} [J = 5/2, 3/2]) ions with Z {<=} 86

    SciTech Connect

    Ivanova, E.P.

    2009-11-15

    Relativistic perturbation theory with a model potential is used for the calculation of energy levels of the states 4f{sub 5/2}, 4f{sub 7/2}, 5s{sub 1/2}, 5p{sub 1/2}, 5p{sub 3/2}, 5d{sub 3/2}, 5d{sub 5/2}, 5f{sub 5/2}, and 5f{sub 7/2} above the 1s{sup 2}2s{sup 2}2p{sup 6}3s{sup 2}3p{sup 6}3d{sup 10}4s{sup 2}4p{sup 6}4d{sup 10} core, with one vacancy 4d{sub 5/2}{sup 9}, 4d{sub 7/2}{sup 9} in the same core, in the silver and rhodium isoelectronic sequences with the maximum nuclear charge Z = 86. The method of extrapolation of the model potential parameter is applied to calculate one-electron and one-vacancy wavefunctions. The wavefunctions of Ag- and Rh-like ions were used to calculate the energies of resonance transitions to the ground state {sup 1}S{sub 0} in Pd-like ions. Good agreement between the theoretical and the experimental energies of the resonance transitions in Pd-like ions indicates the reliability of the results obtained.

  10. Effect of pH and Electrolytes on Adsorption of 2,4-D onto Kaolinite

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Kawamoto, K.; Komatsu, T.; Moldrup, P.

    2006-12-01

    The fate and transport of pesticides in soil can be greatly influenced by adsorption onto clay minerals such as kaolinite. The ionic pesticide 2,4-D (2,4-dichlorophenoxyacetic acid) is one of the most commonly used herbicides. The purpose of this study is to investigate the effect of electrolytes and pH on the adsorption of 2,4- D onto kaolinite. The adsorption coefficient (Kd) of 2,4-D on two types of kaolinite was measured in batch experiments using water and 4 different electrolytes (0.005M CaSO4, 0.005M CaCl2, 0.01M KCl, and 0.01M NaCl). The experiments were carried out with 0.5 g kaolinite at a solid:liquid ratio of 1:20 and at different pH (1.9-6.3). The pH of the solution was controlled by addition of 0.2N of HCl. X-ray diffraction analysis of both kaolinite with and without adsorbed 2,4-D was also done to understand the location of 2,4-D adsorption. The effects of pH and electrolytes on Kd were compared and possible adsorption mechanisms were revealed for 2,4-D adsorption onto the two different types of kaolinite. The results implied that 2,4-D adsorption was higher for an electrolyte solution with monovalent cation than with divalent cation for one type of kaolinite, while no such trend was observed for the other kaolinite. The adsorption of 2,4-D increased significantly with decreasing pH for both types of kaolinite.

  11. Biolabeling with 2,4-dichlorophenoxyacetic acid derivatives: the 2,4-D tag.

    PubMed

    Bade, Steffen; Röckendorf, Niels; Franek, Milan; Gorris, Hans H; Lindner, Buko; Olivier, Verena; Schaper, Klaus-Jürgen; Frey, Andreas

    2009-12-01

    Many bioanalytic and diagnostic procedures rely on labels with which the molecule of interest can be tracked in or discriminated from accompanying like substances. Herein, we describe a new labeling and detection system based on derivatives of 2,4-dichlorophenoxyacetic acid (2,4-D) and anti-2,4-D antibodies. The 2,4-D system is highly sensitive with a K(D) of 7 x 10(-11) M for the hapten-antibody pair, can be used on a large variety of biomolecules such as proteins, peptides, carbohydrates, and nucleic acids, is not hampered by endogenous backgrounds because 2,4-D is a xenobiotic, and is robust because 2,4-D is a very stable compound that withstands the conditions of most reactions usually performed on biomolecules. With this unique blend of properties, the 2,4-D system compares favorably with its rivals digoxigenin (DIG)/anti-DIG and biotin/(strept)avidin and provides an interesting and powerful tool in biomolecular labeling.

  12. Advanced reconstruction of attenuation maps using SPECT emission data only

    NASA Astrophysics Data System (ADS)

    Salomon, André; Goedicke, Andreas; Aach, Til

    2009-02-01

    Today, attenuation corrected SPECT, typically performed using CT or Gadolinium line source based transmission scans, is more and more becoming standard in many medical applications. Moreover, the information about the material density distribution provided by these scans is key for other artifact compensation approaches in advanced SPECT reconstruction. Major drawbacks of these approaches are the additional patient radiation and hardware/maintenance costs as well as the additional workflow effort, e.g. if the CT scans are not performed on a hybrid scanner. It has been investigated in the past, whether it is possible to recover this structural information solely from the SPECT scan data. However, the investigated methods often result in noticeable image artifacts due to cross-dependences between attenuation and activity distribution estimation. With the simultaneous reconstruction method presented in this paper, we aim to effectively prevent these typical cross-talk artifacts using a-priori known atlas information of a human body. At first, an initial 3D shape model is coarsely registered to the SPECT data using anatomical landmarks and each organ structure within the model is identified with its typical attenuation coefficient. During the iterative reconstruction based on a modified ML-EM scheme, the algorithm simultaneously adapts both, the local activity estimation and the 3D shape model in order to improve the overall consistency between measured and estimated sinogram data. By explicitly avoiding topology modifications resulting in a non-anatomical state, we ensure that the estimated attenuation map remains realistic. Several tests with simulated as well as real patient SPECT data were performed to test the proposed algorithm, which demonstrated reliable convergence behaviour in both cases. Comparing the achieved results with available reference data, an overall good agreement for both cold as well as hot activity regions could be observed (mean deviation: -5.98%).

  13. The development of a population of 4D pediatric XCAT phantoms for CT imaging research and optimization

    NASA Astrophysics Data System (ADS)

    Norris, Hannah; Zhang, Yakun; Frush, Jack; Sturgeon, Gregory M.; Minhas, Anum; Tward, Daniel J.; Ratnanather, J. Tilak; Miller, M. I.; Frush, Donald; Samei, Ehsan; Segars, W. Paul

    2014-03-01

    With the increased use of CT examinations, the associated radiation dose has become a large concern, especially for pediatrics. Much research has focused on reducing radiation dose through new scanning and reconstruction methods. Computational phantoms provide an effective and efficient means for evaluating image quality, patient-specific dose, and organ-specific dose in CT. We previously developed a set of highly-detailed 4D reference pediatric XCAT phantoms at ages of newborn, 1, 5, 10, and 15 years with organ and tissues masses matched to ICRP Publication 89 values. We now extend this reference set to a series of 64 pediatric phantoms of a variety of ages and height and weight percentiles, representative of the public at large. High resolution PET-CT data was reviewed by a practicing experienced radiologist for anatomic regularity and was then segmented with manual and semi-automatic methods to form a target model. A Multi-Channel Large Deformation Diffeomorphic Metric Mapping (MC-LDDMM) algorithm was used to calculate the transform from the best age matching pediatric reference phantom to the patient target. The transform was used to complete the target, filling in the non-segmented structures and defining models for the cardiac and respiratory motions. The complete phantoms, consisting of thousands of structures, were then manually inspected for anatomical accuracy. 3D CT data was simulated from the phantoms to demonstrate their ability to generate realistic, patient quality imaging data. The population of pediatric phantoms developed in this work provides a vital tool to investigate dose reduction techniques in 3D and 4D pediatric CT.

  14. RNA interference-mediated knockdown of long-form phosphodiesterase-4D (PDE4D) enzyme reverses amyloid-β42-induced memory deficits in mice.

    PubMed

    Zhang, Cong; Cheng, Yufang; Wang, Haitao; Wang, Chuang; Wilson, Steven P; Xu, Jiangping; Zhang, Han-Ting

    2014-01-01

    Phosphodiesterase-4 (PDE4) inhibitors enhance memory, increase hippocampal neurogenesis, and reverse amyloid-β (Aβ)-induced memory deficits. Here, we examined whether long-form PDE4D knockdown by lentiviral RNA construct containing a specific microRNA/miRNA-mir hairpin structure (4DmiRNA) reversed memory impairment caused by amyloid-β1-42 (Aβ42) in mice using the Morris water maze (MWM) and novelty object recognition tests. Western blotting analysis was used to assess protein levels of cAMP response element-binding protein (CREB, unphosphorylated and phosphorylated [pCREB]), brain-derived neurotrophic factor (BDNF), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and nuclear factor-κB (NF-κB) to explore the neurochemical mechanisms. Aggregated Aβ42 (0.5 μg/side) bilaterally infused in dentate gyrus decreased cAMP levels (p < 0.01) and produced memory deficits in the MWM (p < 0.01) and object recognition tests (p < 0.01). Microinfusions of lentiviruses resulted in downregulated expression of PDE4D4 and 4D5 proteins and reversed Aβ42-induced cAMP decline (p < 0.05) and memory deficits. Treatment also concomitantly increased pCREB (p < 0.05) and BDNF (p < 0.01) and reduced IL-1β (p < 0.05), TNF-α (p < 0.01), and NF-κB (p65) (p < 0.05) in the hippocampus of Aβ42-challenged mice. These results suggest that long-form PDE4D knockdown may offer a promising treatment for memory loss associated with Alzheimer's disease.

  15. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    SciTech Connect

    Li Heng; Li Yupeng; Zhang Xiaodong; Li Xiaoqiang; Liu Wei; Gillin, Michael T.; Zhu, X. Ronald

    2012-12-15

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove the principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose difference

  16. Low external pH replaces 2,4-D in maintaining and multiplying 2,4-D-initiated embryogenic cells of carrot

    NASA Technical Reports Server (NTRS)

    Smith, D. L.; Krikorian, A. D.

    1990-01-01

    A mixed culture comprised of both embryonic globules and nonembryogenic callus was derived from seedling hypocotyls of Daucus carota cv. Scarlet Nantes on 2,4-D- containing medium using well-established methods. Then the mixed cultures were transferred to, and serially subcultured on, a hormone-free medium near pH 4. The medium contained 1 mM NH4+ as the sole nitrogen source. When cultured in this way, embryonic globules were able to multiply without development into later embryo stages. Nonembryogenic callus did not survive. Continuous culture of embryonic globules on this low pH hormone-free medium yielded cultures consisting entirely of preglobular stage proembryos (PGSPs). PGSP cultures have been maintained as such with continuous multiplication for nearly 2 years without loss of embryogenic potential. These hormone-free-maintained PGSPs continue their development to later embryo stages when cultured on the same hormone-free medium buffered at pH 5.8. We show that hormone-free medium near pH 4 can replace 2,4-D in its ability to sustain multiplication of 2,4-D-initiated embryogenic cells of carrot at an acceptable growth rate without their development into later embryo stages. This procedure provides selective conditions that do not permit the growth of non-embryogenic cells while providing an adequate environment for embryogenic cell proliferation and should prove invaluable in studying habituation.

  17. 2,4-D toxicosis.III: An attempt to produce 2,4-D toxicosis in dogs on treated grass plots.

    PubMed

    Arnold, E K; Lovell, R A; Beasley, V R; Parker, A J; Stedelin, J R

    1991-10-01

    Eighteen English pointer dogs were randomly assigned to 3 outdoor grass-plot enclosures (6/enclosure) uniformly sprayed once with either the 2,4-dichlorophenoxyacetic acid (2,4-D) dimethylamine formulation (DMA-4) at the maximum recommended application rate, DMA-4 at 4 times the maximum recommended application rate, or the DMA-4 vehicle alone at 4 times the maximum recommended application rate. A heavy rain shower occurred 24 h after application. The dogs were observed for clinical signs and evaluated using an electroencephalograph, electrocardiograph (lead I), and electromyograph prior to exposure, and either 1 or 7 d after continuous exposure. Clinical examination, hematologic and serum biochemical data were obtained, and serum, urine and kidney 2,4-D were quantified. Half of the dogs from each group were killed after 1 d of continuous exposure, while the other half were killed after 7 d. Gross postmortem and histologic examinations were conducted on each dog. No obvious 2,4-D effects were detected in any of the dogs.

  18. A novel method for 4D measurement-guided planned dose perturbation to estimate patient dose/DVH changes due to interplay

    NASA Astrophysics Data System (ADS)

    Nelms, B.; Feygelman, V.

    2013-06-01

    As IMRT/VMAT technology continues to evolve, so do the dosimetric QA methods. We present the theoretical framework for the novel planned dose perturbation algorithm. It allows not only to reconstruct the 3D volumetric doe on a patient from a measurement in a cylindrical phantom, but also to incorporate the effects of the interplay between the intrafractional organ motion and dynamic delivery. Unlike in our previous work, this 4D dose reconstruction does not require the knowledge of the TPS dose for each control point of the plan, making the method much more practical. Motion is viewed as just another source of error, accounted for by perturbing (morphing) the planned dose distribution based on the limited empirical dose from the phantom measurement. The strategy for empirical verification of the algorithm is presented as the necessary next step.

  19. Capillary Deposition of Complement C4d and C3d in Chinese Renal Allograft Biopsies

    PubMed Central

    Lv, Rong; Zhang, Wei; Han, Fei; Liu, Guangjun; Xie, Wenqing

    2015-01-01

    Background. C3d is a product of both the classic and the alternative complement cascades; however, few studies have addressed the role of C3d in renal biopsies and its relationship with long-term graft survival rate is not very clear. Methods. 94 patients with biopsy-proven acute rejection episodes were included in the study. We investigated the associations between histological findings, clinical examinations, and outcome. Results. The overall prevalence for C4dPTC and C3dPTC was 42.6% and 29.8%. There was a significant association between C3dPTC and C4dPTC (P < 0.001). C3dPTC and C4dPTC were related with histological types (P = 0.024 and P < 0.001, resp.). The long-term survival rate for C4dPTC positive transplants was lower than that of C4dPTC negative transplants, but it was not statistic significant in our study (P = 0.150). The survival rate of C3dPTC positive group was much lower than the negative group (P = 0.014). Patients with double positives for C4dPTC and C3dPTC exhibited the lowest survival rate significantly different from those of the C3dPTC only and C4dPTC only groups (P = 0.01 and P = 0.0037). Conclusions. This longitudinal cohort study has demonstrated that C3d deposition in the PTC was closely related to renal dysfunction and pathological changes. PMID:25821339

  20. Evaluation of 4D CT acquisition methods designed to reduce artifacts.

    PubMed

    Castillo, Sarah J; Castillo, Richard; Castillo, Edward; Pan, Tinsu; Ibbott, Geoffrey; Balter, Peter; Hobbs, Brian; Guerrero, Thomas

    2015-03-08

    Four-dimensional computed tomography (4D CT) is used to account for respiratory motion in radiation treatment planning, but artifacts resulting from the acquisition and postprocessing limit its accuracy. We investigated the efficacy of three experimental 4D CT acquisition methods to reduce artifacts in a prospective institutional review board approved study. Eighteen thoracic patients scheduled to undergo radiation therapy received standard clinical 4D CT scans followed by each of the alternative 4D CT acquisitions: 1) data oversampling, 2) beam gating with breathing irregularities, and 3) rescanning the clinical acquisition acquired during irregular breathing. Relative values of a validated correlation-based artifact metric (CM) determined the best acquisition method per patient. Each 4D CT was processed by an extended phase sorting approach that optimizes the quantitative artifact metric (CM sorting). The clinical acquisitions were also postprocessed by phase sorting for artifact comparison of our current clinical implementation with the experimental methods. The oversampling acquisition achieved the lowest artifact presence among all acquisitions, achieving a 27% reduction from the current clinical 4D CT implementation (95% confidence interval = 34-20). The rescan method presented a significantly higher artifact presence from the clinical acquisition (37%; p < 0.002), the gating acquisition (26%; p < 0.005), and the oversampling acquisition (31%; p < 0.001), while the data lacked evidence of a significant difference between the clinical, gating, and oversampling methods. The oversampling acquisition reduced artifact presence from the current clinical 4D CT implementation to the largest degree and provided the simplest and most reproducible implementation. The rescan acquisition increased artifact presence significantly, compared to all acquisitions, and suffered from combination of data from independent scans over which large internal anatomic shifts occurred.

  1. 4D optimization of scanned ion beam tracking therapy for moving tumors

    NASA Astrophysics Data System (ADS)

    Eley, John Gordon; Newhauser, Wayne David; Lüchtenborg, Robert; Graeff, Christian; Bert, Christoph

    2014-07-01

    Motion mitigation strategies are needed to fully realize the theoretical advantages of scanned ion beam therapy for patients with moving tumors. The purpose of this study was to determine whether a new four-dimensional (4D) optimization approach for scanned-ion-beam tracking could reduce dose to avoidance volumes near a moving target while maintaining target dose coverage, compared to an existing 3D-optimized beam tracking approach. We tested these approaches computationally using a simple 4D geometrical phantom and a complex anatomic phantom, that is, a 4D computed tomogram of the thorax of a lung cancer patient. We also validated our findings using measurements of carbon-ion beams with a motorized film phantom. Relative to 3D-optimized beam tracking, 4D-optimized beam tracking reduced the maximum predicted dose to avoidance volumes by 53% in the simple phantom and by 13% in the thorax phantom. 4D-optimized beam tracking provided similar target dose homogeneity in the simple phantom (standard deviation of target dose was 0.4% versus 0.3%) and dramatically superior homogeneity in the thorax phantom (D5-D95 was 1.9% versus 38.7%). Measurements demonstrated that delivery of 4D-optimized beam tracking was technically feasible and confirmed a 42% decrease in maximum film exposure in the avoidance region compared with 3D-optimized beam tracking. In conclusion, we found that 4D-optimized beam tracking can reduce the maximum dose to avoidance volumes near a moving target while maintaining target dose coverage, compared with 3D-optimized beam tracking.

  2. The Use of Gated and 4D CT Imaging in Planning for Stereotactic Body Radiation Therapy

    SciTech Connect

    D'Souza, Warren D. . E-mail: wdsou001@umaryland.edu; Nazareth, Daryl P.; Zhang Bin; Deyoung, Chad; Suntharalingam, Mohan; Kwok, Young; Yu, Cedric X.; Regine, William F.

    2007-07-01

    The localization of treatment targets is of utmost importance for patients receiving stereotactic body radiation therapy (SBRT), where the dose per fraction is large. While both setup or respiration-induced motion components affect the localization of the treatment volume, the purpose of this work is to describe our management of the intrafraction localization uncertainty induced by normal respiration. At our institution, we have implemented gated computed tomography (CT) acquisition with an active breathing control system (ABC), and 4-dimensional (4D) CT using a skin-based marker and retrospective respiration phase-based image sorting. During gated simulation, 3D CT images were acquired corresponding to end-inhalation and end-exhalation. For 4D CT imaging, 3D CT images were acquired corresponding to 8 phases of the respiratory cycle. In addition to gated or 4D CT images, we acquired a conventional free-breathing CT (FB). For both gated and 4D CT images, the target contours were registered to the FB scan in the planning system. These contours were then combined in the FB image set to form the internal target volume (ITV). Dynamic conformal arc treatment plans were generated for the ITV using the FB scan and the gated or 4D scans with an additional 7-mm margin for patient setup uncertainty. We have described our results for a pancreas and a lung tumor case. Plans were normalized so that the PTV received 95% of the prescription dose. The dose distribution for all the critical structures in the pancreas and lung tumor cases resulted in increased sparing when the ITV was defined using gated or 4D CT images than when the FB scan was used. Our results show that patient-specific target definition using gated or 4D CT scans lead to improved normal tissue sparing.

  3. Isolation and 2,4-D-degrading characteristics of Cupriavidus campinensis BJ71

    PubMed Central

    Han, Lizhen; Zhao, Degang; Li, Cuicui

    2015-01-01

    An indigenous bacterial strain capable of utilizing 2,4-dichlorophenoxyacetic acid as the sole carbon and energy source was isolated from a soil used for grown wheat with a long-term history of herbicide use in Beijing, China. The strain BJ71 was identified as Cupriavidus campinensis based on its 16S rRNA sequence analysis and morphological, physiological, and biochemical characteristics. The degradation characteristics of strain BJ71 were evaluated. The optimal conditions for 2,4-D degradation were as follows: pH 7.0, 30 °C, 3% (v/v) inoculum size, and an initial 2,4-D concentration of 350 mg L−1. Up to 99.57% of the 2,4-D was degraded under optimal conditions after 6 days of incubation. Strain BJ71 was also able to degrade quizalofop and fluroxypyr. This is the first report of a 2,4-D-degrader containing tfdA gene that can utilize these two herbicides. In a biodegradation experiment, 87.13% and 42.53% of 2,4-D (initial concentration, 350 mg kg−1) was degraded in non-sterile and sterilized soil inoculated with BJ71, respectively, after 14 days. The 2,4-D degradation was more rapid in a soil microcosm including BJ71 than in a soil microcosm without BJ71. These results indicate that strain BJ71 is a potential candidate for the bioremediation of soil contaminated with the herbicide 2,4-D. PMID:26273258

  4. Project Reconstruct.

    ERIC Educational Resources Information Center

    Helisek, Harriet; Pratt, Donald

    1994-01-01

    Presents a project in which students monitor their use of trash, input and analyze information via a database and computerized graphs, and "reconstruct" extinct or endangered animals from recyclable materials. The activity was done with second-grade students over a period of three to four weeks. (PR)

  5. Vaginal reconstruction

    SciTech Connect

    Lesavoy, M.A.

    1985-05-01

    Vaginal reconstruction can be an uncomplicated and straightforward procedure when attention to detail is maintained. The Abbe-McIndoe procedure of lining the neovaginal canal with split-thickness skin grafts has become standard. The use of the inflatable Heyer-Schulte vaginal stent provides comfort to the patient and ease to the surgeon in maintaining approximation of the skin graft. For large vaginal and perineal defects, myocutaneous flaps such as the gracilis island have been extremely useful for correction of radiation-damaged tissue of the perineum or for the reconstruction of large ablative defects. Minimal morbidity and scarring ensue because the donor site can be closed primarily. With all vaginal reconstruction, a compliant patient is a necessity. The patient must wear a vaginal obturator for a minimum of 3 to 6 months postoperatively and is encouraged to use intercourse as an excellent obturator. In general, vaginal reconstruction can be an extremely gratifying procedure for both the functional and emotional well-being of patients.

  6. First Steps Toward Ultrasound-Based Motion Compensation for Imaging and Therapy: Calibration with an Optical System and 4D PET Imaging.

    PubMed

    Schwaab, Julia; Kurz, Christopher; Sarti, Cristina; Bongers, André; Schoenahl, Frédéric; Bert, Christoph; Debus, Jürgen; Parodi, Katia; Jenne, Jürgen Walter

    2015-01-01

    Target motion, particularly in the abdomen, due to respiration or patient movement is still a challenge in many diagnostic and therapeutic processes. Hence, methods to detect and compensate this motion are required. Diagnostic ultrasound (US) represents a non-invasive and dose-free alternative to fluoroscopy, providing more information about internal target motion than respiration belt or optical tracking. The goal of this project is to develop an US-based motion tracking for real-time motion correction in radiation therapy and diagnostic imaging, notably in 4D positron emission tomography (PET). In this work, a workflow is established to enable the transformation of US tracking data to the coordinates of the treatment delivery or imaging system - even if the US probe is moving due to respiration. It is shown that the US tracking signal is equally adequate for 4D PET image reconstruction as the clinically used respiration belt and provides additional opportunities in this concern. Furthermore, it is demonstrated that the US probe being within the PET field of view generally has no relevant influence on the image quality. The accuracy and precision of all the steps in the calibration workflow for US tracking-based 4D PET imaging are found to be in an acceptable range for clinical implementation. Eventually, we show in vitro that an US-based motion tracking in absolute room coordinates with a moving US transducer is feasible. PMID:26649277

  7. First Steps Toward Ultrasound-Based Motion Compensation for Imaging and Therapy: Calibration with an Optical System and 4D PET Imaging

    PubMed Central

    Schwaab, Julia; Kurz, Christopher; Sarti, Cristina; Bongers, André; Schoenahl, Frédéric; Bert, Christoph; Debus, Jürgen; Parodi, Katia; Jenne, Jürgen Walter

    2015-01-01

    Target motion, particularly in the abdomen, due to respiration or patient movement is still a challenge in many diagnostic and therapeutic processes. Hence, methods to detect and compensate this motion are required. Diagnostic ultrasound (US) represents a non-invasive and dose-free alternative to fluoroscopy, providing more information about internal target motion than respiration belt or optical tracking. The goal of this project is to develop an US-based motion tracking for real-time motion correction in radiation therapy and diagnostic imaging, notably in 4D positron emission tomography (PET). In this work, a workflow is established to enable the transformation of US tracking data to the coordinates of the treatment delivery or imaging system – even if the US probe is moving due to respiration. It is shown that the US tracking signal is equally adequate for 4D PET image reconstruction as the clinically used respiration belt and provides additional opportunities in this concern. Furthermore, it is demonstrated that the US probe being within the PET field of view generally has no relevant influence on the image quality. The accuracy and precision of all the steps in the calibration workflow for US tracking-based 4D PET imaging are found to be in an acceptable range for clinical implementation. Eventually, we show in vitro that an US-based motion tracking in absolute room coordinates with a moving US transducer is feasible. PMID:26649277

  8. Cloning and expression of the 4D8 gene from Hyalomma asiaticum tick.

    PubMed

    Liu, Z Q; Xia, J; Wang, G L; Kuermanali, N

    2016-01-01

    Hyalomma asiaticum tick, an important ectozoic parasite causes tickle, pain, anemia, weight loss, and paralysis in its hosts, which include humans, cattle, sheep, horses, camels, and hares. The 4D8 gene can be a potential vaccine candidate antigen for H. asiaticum. In the present study, we cloned and expressed the 4D8 gene of H. asiaticum from Xinjiang Province. Primers were designed according to the H. asiaticum tick 4D8 gene sequence available in GenBank. The gene was amplified by reverse transcription-polymerase chain reaction and the fragments were subcloned into the prokaryotic expression vector pET30a and the recombinant vector pET30a-4D8 was constructed. The expressed recombinant protein was purified and its biological activity was investigated by western blot. Results revealed that the recombinant protein was a biologically active fusion protein with a molecular weight of 20 kDa. The purified 4D8 protein would provide a strong foundation for further studies on this protein. PMID:27323189

  9. Identification of novel mutations confirms PDE4D as a major gene causing acrodysostosis.

    PubMed

    Lynch, Danielle C; Dyment, David A; Huang, Lijia; Nikkel, Sarah M; Lacombe, Didier; Campeau, Philippe M; Lee, Brendan; Bacino, Carlos A; Michaud, Jacques L; Bernier, Francois P; Parboosingh, Jillian S; Innes, A Micheil

    2013-01-01

    Acrodysostosis is characterized by nasal hypoplasia, peripheral dysostosis, variable short stature, and intellectual impairment. Recently, mutations in PRKAR1A were reported in patients with acrodysostosis and hormone resistance. Subsequently, mutations in a phosphodiesterase gene (PDE4D) were identified in seven sporadic cases. We sequenced PDE4D in seven acrodysostosis patients from five families. Missense mutations were identified in all cases. Families showed de novo inheritance except one family with three affected children whose father was subsequently found to have subtle features of acrodysostosis. There were no recurrent mutations. Short stature and endocrine resistance are rare in this series; however, cognitive involvement and obesity were frequent. This last finding is relevant given PDE4D is insulin responsive and potentially involved in lipolysis. PDE4D encodes a cyclic AMP regulator and places PDE4D-related acrodysostosis within the same family of diseases as pseudohypoparathyroidism, pseudopseudohypoparathyroidism, PRKAR1A-related acrodysostosis and brachydactyly-mental retardation syndrome; all characterized by cognitive impairment and short distal extremities. PMID:23033274

  10. Improvement of the cine-CT based 4D-CT imaging

    SciTech Connect

    Pan Tinsu; Sun Xiaojun; Luo Dershan

    2007-11-15

    An improved 4D-CT utility has been developed on the GE LightSpeed multislice CT (MSCT) and Discovery PET/CT scanners, which have the cine CT scan capability. Two new features have been added in this 4D-CT over the commercial Advantage 4D-CT from GE. One feature was a new tool for disabling parts of the respiratory signal with irregular respiration and improving the accuracy of phase determination for the respiratory signal from the Varian real-time positioning and monitoring (RPM) system before sorting of the cine CT images into the 4D-CT images. The second feature was to allow generation of the maximum-intensity-projection (MIP), average (AVG) and minimum-intensity-projection (mip) CT images from the cine CT images without a respiratory signal. The implementation enables the assessment of tumor motion in treatment planning with the MIP, AVG, and mip CT images on the GE MSCT and PET/CT scanners without the RPM and the Advantage 4D-CT with a GE Advantage windows workstation. Several clinical examples are included to illustrate this new application.

  11. Review of 2,4-dichlorophenoxyacetic acid (2,4-D) biomonitoring and epidemiology

    PubMed Central

    Burns, Carol J.; Swaen, Gerard M. H.

    2012-01-01

    A qualitative review of the epidemiological literature on the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and health after 2001 is presented. In order to compare the exposure of the general population, bystanders and occupational groups, their urinary levels were also reviewed. In the general population, 2,4-D exposure is at or near the level of detection (LOD). Among individuals with indirect exposure, i.e. bystanders, the urinary 2,4-D levels were also very low except in individuals with opportunity for direct contact with the herbicide. Occupational exposure, where exposure was highest, was positively correlated with behaviors related to the mixing, loading and applying process and use of personal protection. Information from biomonitoring studies increases our understanding of the validity of the exposure estimates used in epidemiology studies. The 2,4-D epidemiology literature after 2001 is broad and includes studies of cancer, reproductive toxicity, genotoxicity, and neurotoxicity. In general, a few publications have reported statistically significant associations. However, most lack precision and the results are not replicated in other independent studies. In the context of biomonitoring, the epidemiology data give no convincing or consistent evidence for any chronic adverse effect of 2,4-D in humans. PMID:22876750

  12. Impact of 4D image quality on the accuracy of target definition.

    PubMed

    Nielsen, Tine Bjørn; Hansen, Christian Rønn; Westberg, Jonas; Hansen, Olfred; Brink, Carsten

    2016-03-01

    Delineation accuracy of target shape and position depends on the image quality. This study investigates whether the image quality on standard 4D systems has an influence comparable to the overall delineation uncertainty. A moving lung target was imaged using a dynamic thorax phantom on three different 4D computed tomography (CT) systems and a 4D cone beam CT (CBCT) system using pre-defined clinical scanning protocols. Peak-to-peak motion and target volume were registered using rigid registration and automatic delineation, respectively. A spatial distribution of the imaging uncertainty was calculated as the distance deviation between the imaged target and the true target shape. The measured motions were smaller than actual motions. There were volume differences of the imaged target between respiration phases. Imaging uncertainties of >0.4 cm were measured in the motion direction which showed that there was a large distortion of the imaged target shape. Imaging uncertainties of standard 4D systems are of similar size as typical GTV-CTV expansions (0.5-1 cm) and contribute considerably to the target definition uncertainty. Optimising and validating 4D systems is recommended in order to obtain the most optimal imaged target shape.

  13. Hydrophobic metabolites of 2,4-dichlorophenoxyacetic acid (2,4-D) in cultured coconut tissue.

    PubMed

    López-Villalobos, Arturo; Hornung, Roland; Dodds, Peter F

    2004-10-01

    Cultures of inflorescence and plumular tissues of coconut palm (Cocos nucifera L.) were maintained in the presence of the auxin, [14C]2,4-dichlorophenoxyacetic acid (2,4-D), so that its metabolic fate could be studied. Thin layer chromatography of methanol extracts of the plumular tissue showed that four classes of metabolites, as well as the unchanged acid, were recovered in the extract. In inflorescence tissue, only the unchanged acid and the most polar class of metabolites (metabolite I) were recovered. Metabolite I was shown to consist mostly of a mixture of sugar conjugates and metabolite II (the next most polar) was an unidentified basic metabolite. Metabolites III and IV were both novel triacylglycerol analogues in which one of the natural fatty acids was replaced with a chain-elongated form of 2,4-D. Reversed-phase thin layer chromatography was used to identify the 2,4-D-derived acids and it was found that metabolite III contained the 2,4-dichlorophenoxy-moiety attached to a chain-length of between 2 and 12 carbons, whereas metabolite IV contained 12, 14 and 16 carbon chain lengths. In inflorescence tissue, and in plumular tissue at low sucrose or 2,4-D concentrations and after short periods in culture, metabolite I predominated. The other metabolites increased as a percentage when plumular culture was prolonged or when sucrose or 2,4-D concentrations were raised. These changes correlated with better development of the explant.

  14. Allowing for model error in strong constraint 4D-Var

    NASA Astrophysics Data System (ADS)

    Howes, Katherine; Lawless, Amos; Fowler, Alison

    2016-04-01

    Four dimensional variational data assimilation (4D-Var) can be used to obtain the best estimate of the initial conditions of an environmental forecasting model, namely the analysis. In practice, when the forecasting model contains errors, the analysis from the 4D-Var algorithm will be degraded to allow for errors later in the forecast window. This work focusses on improving the analysis at the initial time by allowing for the fact that the model contains error, within the context of strong constraint 4D-Var. The 4D-Var method developed acknowledges the presence of random error in the model at each time step by replacing the observation error covariance matrix with an error covariance matrix that includes both observation error and model error statistics. It is shown that this new matrix represents the correct error statistics of the innovations in the presence of model error. A method for estimating this matrix using innovation statistics, without requiring prior knowledge of the model error statistics, is presented. The method is demonstrated numerically using a non-linear chaotic system with erroneous parameter values. We show that that the new method works to reduce the analysis error covariance when compared with a standard strong constraint 4D-Var scheme. We discuss the fact that an improved analysis will not necessarily provide a better forecast.

  15. Review of 2,4-dichlorophenoxyacetic acid (2,4-D) biomonitoring and epidemiology.

    PubMed

    Burns, Carol J; Swaen, Gerard M H

    2012-10-01

    A qualitative review of the epidemiological literature on the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and health after 2001 is presented. In order to compare the exposure of the general population, bystanders and occupational groups, their urinary levels were also reviewed. In the general population, 2,4-D exposure is at or near the level of detection (LOD). Among individuals with indirect exposure, i.e. bystanders, the urinary 2,4-D levels were also very low except in individuals with opportunity for direct contact with the herbicide. Occupational exposure, where exposure was highest, was positively correlated with behaviors related to the mixing, loading and applying process and use of personal protection. Information from biomonitoring studies increases our understanding of the validity of the exposure estimates used in epidemiology studies. The 2,4-D epidemiology literature after 2001 is broad and includes studies of cancer, reproductive toxicity, genotoxicity, and neurotoxicity. In general, a few publications have reported statistically significant associations. However, most lack precision and the results are not replicated in other independent studies. In the context of biomonitoring, the epidemiology data give no convincing or consistent evidence for any chronic adverse effect of 2,4-D in humans.

  16. Identification of novel mutations confirms PDE4D as a major gene causing acrodysostosis.

    PubMed

    Lynch, Danielle C; Dyment, David A; Huang, Lijia; Nikkel, Sarah M; Lacombe, Didier; Campeau, Philippe M; Lee, Brendan; Bacino, Carlos A; Michaud, Jacques L; Bernier, Francois P; Parboosingh, Jillian S; Innes, A Micheil

    2013-01-01

    Acrodysostosis is characterized by nasal hypoplasia, peripheral dysostosis, variable short stature, and intellectual impairment. Recently, mutations in PRKAR1A were reported in patients with acrodysostosis and hormone resistance. Subsequently, mutations in a phosphodiesterase gene (PDE4D) were identified in seven sporadic cases. We sequenced PDE4D in seven acrodysostosis patients from five families. Missense mutations were identified in all cases. Families showed de novo inheritance except one family with three affected children whose father was subsequently found to have subtle features of acrodysostosis. There were no recurrent mutations. Short stature and endocrine resistance are rare in this series; however, cognitive involvement and obesity were frequent. This last finding is relevant given PDE4D is insulin responsive and potentially involved in lipolysis. PDE4D encodes a cyclic AMP regulator and places PDE4D-related acrodysostosis within the same family of diseases as pseudohypoparathyroidism, pseudopseudohypoparathyroidism, PRKAR1A-related acrodysostosis and brachydactyly-mental retardation syndrome; all characterized by cognitive impairment and short distal extremities.

  17. Hydrophobic metabolites of 2,4-dichlorophenoxyacetic acid (2,4-D) in cultured coconut tissue.

    PubMed

    López-Villalobos, Arturo; Hornung, Roland; Dodds, Peter F

    2004-10-01

    Cultures of inflorescence and plumular tissues of coconut palm (Cocos nucifera L.) were maintained in the presence of the auxin, [14C]2,4-dichlorophenoxyacetic acid (2,4-D), so that its metabolic fate could be studied. Thin layer chromatography of methanol extracts of the plumular tissue showed that four classes of metabolites, as well as the unchanged acid, were recovered in the extract. In inflorescence tissue, only the unchanged acid and the most polar class of metabolites (metabolite I) were recovered. Metabolite I was shown to consist mostly of a mixture of sugar conjugates and metabolite II (the next most polar) was an unidentified basic metabolite. Metabolites III and IV were both novel triacylglycerol analogues in which one of the natural fatty acids was replaced with a chain-elongated form of 2,4-D. Reversed-phase thin layer chromatography was used to identify the 2,4-D-derived acids and it was found that metabolite III contained the 2,4-dichlorophenoxy-moiety attached to a chain-length of between 2 and 12 carbons, whereas metabolite IV contained 12, 14 and 16 carbon chain lengths. In inflorescence tissue, and in plumular tissue at low sucrose or 2,4-D concentrations and after short periods in culture, metabolite I predominated. The other metabolites increased as a percentage when plumular culture was prolonged or when sucrose or 2,4-D concentrations were raised. These changes correlated with better development of the explant. PMID:15474562

  18. Investigation of the accumulation of 2,4-dichlorophenoxyacetic acid (2,4-D) in rat kidneys.

    PubMed

    Aydin, Handan; Ozdemir, Nurullah; Uzunören, Nuray

    2005-10-01

    The accumulation of 2,4-dichlorophenoxyacetic acid (2,4-D) and its metabolite 2,4-dichlorophenol (2,4-DCP) in the kidneys of rats was investigated. Male and female Sprague-Dawley rats were given 2,4-D in drinking water and food for 30 days. Group A (control group) was fed a normal diet, Group B was fed 50 ppm 2,4-D in 15 g food, Group C received 100 ppm 2,4-D in 15 g food, Group D received 25 ppm 2,4-D in 15 ml drinking water and Group E was given 50 ppm 2,4-D in 15 ml of drinking water. Levels of 2,4-D and 2,4-DCP in kidneys were determined using high performance liquid chromatography (HPLC). It was observed that at low doses of 2,4-D, the metabolite, 2,4-DCP found in the kidneys.

  19. 2D:4D finger ratio positively correlates with total cerebral cortex in males.

    PubMed

    Darnai, Gergely; Plózer, Enikő; Perlaki, Gábor; Orsi, Gergely; Nagy, Szilvia Anett; Horváth, Réka; Schwarcz, Attila; Kovács, Norbert; Altbäcker, Anna; Janszky, József; Clemens, Zsófia

    2016-02-26

    Although there is evidence that the ratio of 2nd-4th digit length (2D:4D) correlates with prenatal testosterone level, psychological and health traits only two studies have assessed the relationship with brain morphological features. Here we investigated the association between the 2D:4D ratio and several brain subvolumes. Seventy-five subjects between the ages of 18 and 30 were included in the study. The length of the 2nd and 4th digits were measured with an electronic vernier caliper while MRI measurements were performed on a Siemens Magnetom Trio Tim (3T) system. Freesurfer software suite was used for volumetric segmentation. Finger ratio significantly positively correlated with total cerebral cortex, total cerebellar white matter and total cerebellar cortex in males but not in females. Our results indicate that prenatal testosterone, as estimated by the 2D:4D ratio has an effect on adult brain morphology in males. PMID:26780566

  20. Proximal femoral focal deficiency of the fetus - early 3D/4D prenatal ultrasound diagnosis.

    PubMed

    Kudla, Marek J; Beczkowska-Kielek, Aleksandra; Kutta, Katarzyna; Partyka-Lasota, Justyna

    2016-09-01

    Proximal Femoral Focal Deficiency (PFFD) is a rare congenital syndrome of unknown etiology. Additional disorders can be present up to 70% of PFFD cases. Management (including termination) depends on the severity of the malformation. We present a case of a 32-year-old woman referred for routine ultrasound examination in the 12th week of pregnancy. Detailed 3D/4D evaluation revealed asymmetry of lower limbs and diagnosis of isolated PFFD was established. Parents were fully informed and decided to continue the pregnancy. We stress here the importance of early 3D/4D ultrasound diagnosis. Our paper presents the earliest case where the diagnosis of PFFD was established with 3D/4D ultrasound. PMID:27622419

  1. Interaction of 2,4-dichlorophenoxyacetic acid (2,4-D) with cell and model membranes.

    PubMed

    Suwalsky, M; Benites, M; Villena, F; Aguilar, F; Sotomayor, C P

    1996-12-01

    2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide, is a component of the "agent orange' whose toxicity has been extensively studied without definite conclusions. In order to evaluate its perturbing effect upon cell membranes, 2,4-D was made to interact with human erythrocytes and molecular models. These studies were performed by scanning electron microscopy on red cells, fluorescence spectroscopy on dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles and X-ray diffraction on multilayers of DMPC and dimyristoylphosphatidylethanolamine (DMPE). It was observed that 2,4-D induced a pronounced shape change to the erythrocytes. This effect is explained by the herbicide interaction with the outer monolayer of the red cell membrane. PMID:8972711

  2. Synthesis, biological activities and pharmacokinetic properties of new fluorinated derivatives of selective PDE4D inhibitors.

    PubMed

    Brullo, Chiara; Massa, Matteo; Villa, Carla; Ricciarelli, Roberta; Rivera, Daniela; Pronzato, Maria Adelaide; Fedele, Ernesto; Barocelli, Elisabetta; Bertoni, Simona; Flammini, Lisa; Bruno, Olga

    2015-07-01

    A new series of selective PDE4D inhibitors has been designed and synthesized by replacing 3-methoxy group with 3-difluoromethoxy isoster moiety in our previously reported cathecolic structures. All compounds showed a good PDE4D3 inhibitory activity, most of them being inactive toward other PDE4 isoforms (PDE4A4, PDE4B2 and PDE4C2). Compound 3b, chosen among the synthesized compounds as the most promising in terms of inhibitory activity, selectivity and safety, showed an improved pharmacokinetic profile compared to its non fluorinated analogue. Spontaneous locomotor activity, assessed in an open field apparatus, showed that, differently from rolipram and diazepam, selective PDE4D inhibitors, such as compounds 3b, 5b and 7b, did not affect locomotion, whereas compound 1b showed a tendency to reduce the distance traveled and to prolong the immobility period, possibly due to a poor selectivity.

  3. A practical introduction to the hemodynamic analysis of the cardiovascular system with 4D Flow MRI.

    PubMed

    Pineda Zapata, J A; Delgado de Bedout, J A; Rascovsky Ramírez, S; Bustamante, C; Mesa, S; Calvo Betancur, V D

    2014-01-01

    The 4D Flow MRI technique provides a three-dimensional representation of blood flow over time, making it possible to evaluate the hemodynamics of the cardiovascular system both qualitatively and quantitatively. In this article, we describe the application of the 4D Flow technique in a 3T scanner; in addition to the technical parameters, we discuss the advantages and limitations of the technique and its possible clinical applications. We used 4D Flow MRI to study different body areas (chest, abdomen, neck, and head) in 10 volunteers. We obtained 3D representations of the patterns of flow and quantitative hemodynamic measurements. The technique makes it possible to evaluate the pattern of blood flow in large and midsize vessels without the need for exogenous contrast agents.

  4. Uptake of 2,4-D in higher plants from artificial rain.

    PubMed

    Løkke, H

    1984-02-01

    Sinapis alba L., Lapsana communis L., Achillea millefolium L., Brassica napus L., Lactuca sativa L., and Lycopersicum esculentum L. were exposed to 2,4-dichlorophenoxy [2-14C]acetic acid (2,4-D) at 10 micrograms liter-1 in artificial rain, pH 6.5 and 3.3. The 2,4-D was absorbed in all species tested. Concentrations of parent 2,4-D appeared at the highest level in Achillea (0.1 mg kg-1 dry wt), and at zero level in Lycopersicum. Twenty-one daily treatments at pH 6.5 for 30-min periods increased dry-matter concentrations (P less than or equal to 0.05) in the leaves of Achillea and decreased those in Brassica. No change in dry-matter concentration was observed in the leaves of Brassica by seven daily treatments for 30-min periods at pH 3.3.

  5. Uptake of 2,4-D in higher plants from artificial rain

    SciTech Connect

    Lokke, H.

    1984-02-01

    Sinapis alba L., Lapsana communis L., Achillea millefolium L., Brassica napus L., Lactuca sativa L., and Lycopersicum esculentum L. were exposed to 2,4-dichlorophenoxy (2-/sup 14/C)acetic acid (2,4-D) at 10 micrograms liter-1 in artificial rain, pH 6.5 and 3.3. The 2,4-D was absorbed in all species tested. Concentrations of parent 2,4-D appeared at the highest level in Achillea (0.1 mg kg-1 dry wt), and at zero level in Lycopersicum. Twenty-one daily treatments at pH 6.5 for 30-min periods increased dry-matter concentrations in the leaves of Achillea and decreased those in Brassica. No change in dry-matter concentration was observed in the leaves of Brassica by seven daily treatments for 30-min periods at pH 3.3.

  6. Live 4D optical coherence tomography for early embryonic mouse cardiac phenotyping

    NASA Astrophysics Data System (ADS)

    Lopez, Andrew L.; Wang, Shang; Larin, Kirill V.; Overbeek, Paul A.; Larina, Irina V.

    2016-03-01

    Studying embryonic mouse development is important for our understanding of normal human embryogenesis and the underlying causes of congenital defects. Our research focuses on imaging early development in the mouse embryo to specifically understand cardiovascular development using optical coherence tomography (OCT). We have previously developed imaging approaches that combine static embryo culture, OCT imaging and advanced image processing to visualize the whole live mouse embryos and obtain 4D (3D+time) cardiodynamic datasets with cellular resolution. Here, we present the study of using 4D OCT for dynamic imaging of early embryonic heart in live mouse embryos to assess mutant cardiac phenotypes during development, including a cardiac looping defect. Our results indicate that the live 4D OCT imaging approach is an efficient phenotyping tool that can reveal structural and functional cardiac defects at very early stages. Further studies integrating live embryonic cardiodynamic phenotyping with molecular and genetic approaches in mouse mutants will help to elucidate the underlying signaling defects.

  7. Attosecond delay of xenon 4 d photoionization at the giant resonance and Cooper minimum

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, Maia; Madjet, Mohamed El-Amine; Chakraborty, Himadri S.

    2016-07-01

    A Kohn-Sham time-dependent local-density-functional scheme is utilized to predict attosecond time delays of xenon 4 d photoionization that involves the 4 d giant dipole resonance and Cooper minimum. The fundamental effect of electron correlations to uniquely determine the delay at both regions is demonstrated. In particular, for the giant dipole resonance, the delay underpins strong collective effect, emulating the recent prediction at C60 giant plasmon resonance [T. Barillot et al., Phys. Rev. A 91, 033413 (2015), 10.1103/PhysRevA.91.033413]. For the Cooper minimum, a qualitative similarity with a photorecombination experiment near argon 3 p minimum [S. B. Schoun et al., Phys. Rev. Lett. 112, 153001 (2014), 10.1103/PhysRevLett.112.153001] is found. The result should encourage attosecond measurements of Xe 4 d photoemission.

  8. The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China

    PubMed Central

    Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian

    2016-01-01

    The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology. PMID:27375513

  9. The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China.

    PubMed

    Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian

    2016-01-01

    The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology. PMID:27375513

  10. Exome sequencing identifies PDE4D mutations as another cause of acrodysostosis.

    PubMed

    Michot, Caroline; Le Goff, Carine; Goldenberg, Alice; Abhyankar, Avinash; Klein, Céline; Kinning, Esther; Guerrot, Anne-Marie; Flahaut, Philippe; Duncombe, Alice; Baujat, Genevieve; Lyonnet, Stanislas; Thalassinos, Caroline; Nitschke, Patrick; Casanova, Jean-Laurent; Le Merrer, Martine; Munnich, Arnold; Cormier-Daire, Valérie

    2012-04-01

    Acrodysostosis is a rare autosomal-dominant condition characterized by facial dysostosis, severe brachydactyly with cone-shaped epiphyses, and short stature. Moderate intellectual disability and resistance to multiple hormones might also be present. Recently, a recurrent mutation (c.1102C>T [p.Arg368*]) in PRKAR1A has been identified in three individuals with acrodysostosis and resistance to multiple hormones. After studying ten unrelated acrodysostosis cases, we report here de novo PRKAR1A mutations in five out of the ten individuals (we found c.1102C>T [p.Arg368(∗)] in four of the ten and c.1117T>C [p.Tyr373His] in one of the ten). We performed exome sequencing in two of the five remaining individuals and selected phosphodiesterase 4D (PDE4D) as a candidate gene. PDE4D encodes a class IV cyclic AMP (cAMP)-specific phosphodiesterase that regulates cAMP concentration. Exome analysis detected heterozygous PDE4D mutations (c.673C>A [p.Pro225Thr] and c.677T>C [p.Phe226Ser]) in these two individuals. Screening of PDE4D identified heterozygous mutations (c.568T>G [p.Ser190Ala] and c.1759A>C [p.Thr587Pro]) in two additional acrodysostosis cases. These mutations occurred de novo in all four cases. The four individuals with PDE4D mutations shared common clinical features, namely characteristic midface and nasal hypoplasia and moderate intellectual disability. Metabolic screening was normal in three of these four individuals. However, resistance to parathyroid hormone and thyrotropin was consistently observed in the five cases with PRKAR1A mutations. Finally, our study further supports the key role of the cAMP signaling pathway in skeletogenesis. PMID:22464250

  11. The 2D:4D-Ratio and Neuroticism Revisited: Empirical Evidence from Germany and China.

    PubMed

    Sindermann, Cornelia; Li, Mei; Sariyska, Rayna; Lachmann, Bernd; Duke, Éilish; Cooper, Andrew; Warneck, Lidia; Montag, Christian

    2016-01-01

    The 2D:4D-Ratio, as an indirect measure of the fetal testosterone to estradiol ratio, is potentially very important for understanding and explaining different personality traits. It was the aim of the present study to replicate the findings from Fink et al. (2004) about the relation between individual differences in 2D:4D-Ratios and the Five Factor Model in different cultural groups. Therefore a sample of n = 78 Chinese and n = 370 German participants was recruited. Every participant provided hand scans of both hands, from which 2D:4D-Ratios were computed. Moreover, all participants filled in the NEO Five Factor Inventory (NEO-FFI). Significant sex differences were found for ratios of both hands in the expected direction, with females showing higher ratios than males. With respect to links between personality and the digit ratio, a positive association was observed between 2D:4D-Ratio and Neuroticism in females, as shown in the earlier study. These findings were observed in both female subsamples from China and Germany, as well as in the full sample of participants. But in contrast to the results for the whole and the German female sample, where 2D:4D-Ratio of both hands were related to Neuroticism, in the Chinese female sample only left hand 2D:4D-Ratio was significantly and positively related to Neuroticism. There were no significant correlations found in any of the male samples. Thus, prenatal exposure to sex steroids appears to influence the personality factor Neuroticism in females specifically. This finding potentially has implications for mental health, as Neuroticism has been shown to be a risk factor for various forms of psychopathology.

  12. Advances in 4D Treatment Planning for Scanned Particle Beam Therapy — Report of Dedicated Workshops

    PubMed Central

    Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

    2014-01-01

    We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue. PMID:24354749

  13. TOPO-EUROPE: Studying Continental Topography and Deep Earth - Surface Processes in 4D

    NASA Astrophysics Data System (ADS)

    Cloetingh, S.; Topo-Europe Science Community, The

    2009-04-01

    Topography influences various aspects of society, not only in terms of the slow process of landscape evolution but also through climate (e.g. mountain building). Topographic evolution (changes in land, water and sea level) can seriously affect human life, as well as terrestrial geo-ecosystems. When fresh water or sea-water levels rise, or when land subsides, the risk of flooding increases. This directly affects local geo- ecosystems and human settlements. On the other hand, declining water levels and uplift may lead to a higher risk of erosion and even desertification. Similar examples could be given for groundwater, early life and climate change. Studying these aspects in an integrated way is essential to forward solid Earth Sciences in response to the needs of society (see http://www.yearofplanetearth.org/). To quantify topography evolution in space and time, understanding of the coupled deep Earth and surface processes is a requisite. The TOPO-EUROPE initiative of the International Lithophere Program (ILP) addresses the 4-D topography of the orogens and intra-plate regions of Europe through a multidisciplinary approach linking geology, geophysics, geodesy and geotechnology. TOPO-EUROPE integrates monitoring, imaging, reconstruction and modelling of the interplay between processes controlling continental topography and related natural hazards. Until now, research on neotectonics and related topography development of orogens and intra-plate regions has received little attention. TOPO-EUROPE initiates a number of novel studies on the quantification of rates of vertical motions, related tectonically controlled river evolution and land subsidence in carefully selected natural laboratories in Europe. From orogen through platform to continental margin, these natural laboratories include the Alps/Carpathians-Pannonian Basin System, the West and Central European Platform, the Apennines-Tyrrhenian-Maghrebian and the Aegean-Anatolian regions, the Iberian Peninsula and the

  14. TOPO-EUROPE: Studying Continental Topography and Deep Earth - Surface Processes in 4D

    NASA Astrophysics Data System (ADS)

    Cloetingh, S.; Team, T.

    2008-12-01

    Topography influences various aspects of society, not only in terms of the slow process of landscape evolution but also through climate (e.g. mountain building). Topographic evolution (changes in land, water and sea level) can seriously affect human life, as well as terrestrial geo-ecosystems. When fresh water or sea-water levels rise, or when land subsides, the risk of flooding increases. This directly affects local geo- ecosystems and human settlements. On the other hand, declining water levels and uplift may lead to a higher risk of erosion and even desertification. Similar examples could be given for groundwater, early life and climate change. Studying these aspects in an integrated way is essential to forward solid Earth Sciences in response to the needs of society (see http://www.yearofplanetearth.org/). To quantify topography evolution in space and time, understanding of the coupled deep Earth and surface processes is a requisite. The TOPO-EUROPE initiative of the International Lithophere Program (ILP) addresses the 4-D topography of the orogens and intra-plate regions of Europe through a multidisciplinary approach linking geology, geophysics, geodesy and geotechnology. TOPO-EUROPE integrates monitoring, imaging, reconstruction and modelling of the interplay between processes controlling continental topography and related natural hazards. Until now, research on neotectonics and related topography development of orogens and intra-plate regions has received little attention. TOPO-EUROPE initiates a number of novel studies on the quantification of rates of vertical motions, related tectonically controlled river evolution and land subsidence in carefully selected natural laboratories in Europe. From orogen through platform to continental margin, these natural laboratories include the Alps/Carpathians-Pannonian Basin System, the West and Central European Platform, the Apennines-Tyrrhenian-Maghrebian and the Aegean-Anatolian regions, the Iberian Peninsula and the

  15. Impact of Petrophysical Experiments on Quantitative Interpretation of 4D Seismic Data at Ketzin, Germany

    NASA Astrophysics Data System (ADS)

    Ivanova, A.; Lueth, S.

    2015-12-01

    Petrophysical investigations for CCS concern relationships between physical properties of rocks and geophysical observations for understanding behavior of injected CO2 in a geological formation. In turn 4D seismic surveying is a proven tool for CO2 monitoring. At the Ketzin pilot site (Germany) 4D seismic data have been acquired by means of a baseline (pre-injection) survey in 2005 and monitor surveys in 2009 and 2012. At Ketzin CO2 was injected in supercritical state from 2008 to 2013 in a sandstone saline aquifer (Stuttgart Formation) at a depth of about 650 m. The 4D seismic data from Ketzin reflected a pronounced effect of this injection. Seismic forward modeling using results of petrophysical experiments on two core samples fromthe target reservoir confirmed that effects of the injected CO2 on the 4D seismic data are significant. The petrophysical data were used in that modeling in order to reflect changes due to the CO2 injection in acoustic parameters of the reservoir. These petrophysical data were further used for a successful quantitative interpretation of the 4D seismic data at Ketzin. Now logs from a well (drilled in 2012) penetrating the reservoir containing information about changes in the acoustic parameters of the reservoir due to the CO2 injection are available. These logs were used to estimate impact of the petrophysical data on the qualitative and quantitative interpretation of the 4D seismic data at Ketzin. New synthetic seismograms were computed using the same software and the same wavelet as the old ones apart from the only difference and namely the changes in the input acoustic parameters would not be affected with any petrophysical experiments anymore. Now these changes were put in computing directly from the logs. In turn the new modelled changes due to the injection in the newly computed seismograms do not include any effects of the petrophysical data anymore. Key steps of the quantitative and qualitative interpretation of the 4D seismic

  16. Fast X-ray micro-CT for real-time 4D observation

    NASA Astrophysics Data System (ADS)

    Takano, H.; Yoshida, K.; Tsuji, T.; Koyama, T.; Tsusaka, Y.; Kagoshima, Y.

    2009-09-01

    Fast X-ray computed tomography (CT) system with sub-second order measurement for single CT acquisition has been developed. The system, consisting of a high-speed sample rotation stage and a high-speed X-ray camera, is constructed at synchrotron radiation beamline in order to utilize fully intense X-rays. A time-resolving CT movie (i.e. 4D CT) can be available by operating the fast CT system continuously. Real-time observation of water absorbing process of super-absorbent polymer (SAP) has been successfully performed with the 4D CT operation.

  17. No relation between 2D : 4D fetal testosterone marker and dyslexia.

    PubMed

    Boets, Bart; De Smedt, Bert; Wouters, Jan; Lemay, Katrien; Ghesquière, Pol

    2007-09-17

    It has been suggested that high levels of prenatal testosterone exposure are implied in the aetiology of dyslexia and its frequently co-occurring sensory problems. This study examined 2D : 4D digit ratio (a marker of fetal testosterone exposure) in dyslexic and normal reading children. No group differences in 2D : 4D were observed. Digit ratio did not show the postulated relation with reading, spelling, phonological ability, speech perception, auditory processing and visual processing. These findings challenge the validity of theories that allocate a prominent role to fetal testosterone exposure in the aetiology of dyslexia and its sensory impairments. PMID:17712280

  18. Clinical Utility of 4D FDG-PET/CT Scans in Radiation Treatment Planning

    SciTech Connect

    Aristophanous, Michalis; Sher, David J.; Allen, Aaron M.; Larson, Elysia; Chen, Aileen B.

    2012-01-01

    Purpose: The potential role of four-dimensional (4D) positron emission tomography (PET)/computed tomography (CT) in radiation treatment planning, relative to standard three-dimensional (3D) PET/CT, was examined. Methods and Materials: Ten patients with non-small-cell lung cancer had sequential 3D and 4D [{sup 18}F]fluorodeoxyglucose PET/CT scans in the treatment position prior to radiation therapy. The gross tumor volume and involved lymph nodes were contoured on the PET scan by use of three different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; a technique with a constant threshold of standardized uptake value (SUV) greater than 2.5; and an automatic segmentation technique. For each technique, the tumor volume was defined on the 3D scan (VOL3D) and on the 4D scan (VOL4D) by combining the volume defined on each of the five breathing phases individually. The range of tumor motion and the location of each lesion were also recorded, and their influence on the differences observed between VOL3D and VOL4D was investigated. Results: We identified and analyzed 22 distinct lesions, including 9 primary tumors and 13 mediastinal lymph nodes. Mean VOL4D was larger than mean VOL3D with all three techniques, and the difference was statistically significant (p < 0.01). The range of tumor motion and the location of the tumor affected the magnitude of the difference. For one case, all three tumor definition techniques identified volume of moderate uptake of approximately 1 mL in the hilar region on the 4D scan (SUV maximum, 3.3) but not on the 3D scan (SUV maximum, 2.3). Conclusions: In comparison to 3D PET, 4D PET may better define the full physiologic extent of moving tumors and improve radiation treatment planning for lung tumors. In addition, reduction of blurring from free-breathing images may reveal additional information regarding regional disease.

  19. Efficacy evaluation of retrospectively applying the Varian normal breathing predictive filter for volume definition and artifact reduction in 4D CT lung patients.

    PubMed

    Malone, Ciaran; Rock, Luke; Skourou, Christina

    2014-05-08

    Phase-based sorting of four-dimensional computed tomography (4D CT) datasets is prone to image artifacts due to patient's breathing irregularities that occur during the image acquisition. The purpose of this study is to investigate the effect of the Varian normal breathing predictive filter (NBPF) as a retrospective phase-sorting parameter in 4D CT. Ten 4D CT lung cancer datasets were obtained. The volumes of all tumors present, as well as the total lung volume, were calculated on the maximum intensity projection (MIP) images as well as each individual phase image. The NBPF was varied retrospectively within the available range, and changes in volume and image quality were recorded. The patients' breathing trace was analysed and the magnitude and location of any breathing irregularities were correlated to the behavior of the NBPF. The NBPF was found to have a considerable effect on the quality of the images in MIP and single-phase datasets. When used appropriately, the NBPF is shown to have the ability to account for and correct image artifacts. However, when turned off (0%) or set above a critical level (approximately 40%), it resulted in erroneous volume reconstructions with variations in tumor volume up to 26.6%. Those phases associated with peak inspiration were found to be more susceptible to changes in the NBPF. The NBPF settings selected prior to exporting the breathing trace for patients evaluated using 4D CT directly affect the accuracy of the targeting and volume estimation of lung tumors. Recommendations are made to address potential errors in patient anatomy introduced by breathing irregularities, specifically deep breath or cough irregularities, by implementing the proper settings and use of this tool.

  20. SU-C-BRF-04: Delivered 4D Dose Calculation for Lung-VMAT Patients Using In- Treatment CBCT and LINAC Log Data

    SciTech Connect

    Saotome, N; Haga, A; Imae, T; Kida, S; Nakano, M; Yamashita, H; Nakagawa, K; Ohtomo, K

    2014-06-15

    Purpose: To verify the delivered four-dimensional (4D) dose distribution for the lung VMAT using in-treatment 4D cone-beam CT (CBCT) and LINAC log data. Methods: Three patients for lung stereotactic radiotherapy (SRT) were treated by single-arc volumetric modulated arc therapy (VMAT) created by SmartArc in Pinnacle v9.2 (Philips, USA).Kilovoltage (kV) projection images were acquired during VMAT delivery using the x-ray volumetric imager, XVI (Elekta, UK). LINAC log data were also recorded via iCom interface (Elekta, UK). Subsequently, the iCom data format was converted to Pinnacle data format, thereby allowing Pinnacle to read actual MLC positions, jaw positions, gantry angles and MUs. These parameters were categorized into four groups according to patient's respiratory phase. The patient respiratory phase was determined from kV-projection images by in-house phase recognizing software. By exporting these data back to Pinnacle, in-treatment dose distributions for each respiratory phase were obtained by combining calculated dose having a particular phase. The 4D CBCT were reconstructed by in-house program. The density in the structures on the CBCT was overridden by the average density in the corresponding structures on the planning CT for the dose calculation. The dose indexes, such as maximum, minimum, mean dose in the target were compared among the plan, in-treatment 3D calculation, and in-treatment 4D calculation. Results: The day-to-day variation of the delivered dose was observed for all three patients. The maximum difference was 5.9% for the minimum dose in the target. Difference for the mean dose was found to be small (1.1% at maximum). Conclusion: We have obtained in-treatment dose distribution for each of the different respiratory phases using in-treatment 4D CBCT and LINAC log data during lung VMAT delivery. Our result indicate a small but significant dose difference between the 3D and 4D calculations for the case of large target traveling.

  1. Optical diffraction tomography using a digital micromirror device for stable measurements of 4D refractive index tomography of cells

    NASA Astrophysics Data System (ADS)

    Shin, Seungwoo; Kim, Kyoohyun; Kim, Taeho; Yoon, Jonghee; Hong, Kihyun; Park, Jinah; Park, YongKeun

    2016-03-01

    Optical diffraction tomography (ODT) is an interferometric microscopy technique capable of measuring 3-D refractive index (RI) distribution of transparent samples. Multiple 2-D holograms of a sample illuminated with various angles are measured, from which 3-D RI map of the sample is reconstructed via the diffraction theory. ODT has been proved as a powerful tool for the study of biological cells, due to its non-invasiveness, label-free and quantitative imaging capability. Recently, our group has demonstrated that a digital micromirror device (DMD) can be exploited for fast and precise control of illumination beams for ODT. In this work, we systematically study the precision and stability of the ODT system equipped with a DMD and present measurements of 3-D and 4-D RI maps of various types of live cells including human red blood cells, white blood cells, hepatocytes, and HeLa cells. Furthermore, we also demonstrate the effective visualization of 3-D RI maps of live cells utilizing the measured information about the values and gradient of RI tomograms.

  2. A method for deriving a 4D-interpolated balanced planning target for mobile tumor radiotherapy

    SciTech Connect

    Roland, Teboh; Hales, Russell; McNutt, Todd; Wong, John; Simari, Patricio; Tryggestad, Erik

    2012-01-15

    Purpose: Tumor control and normal tissue toxicity are strongly correlated to the tumor and normal tissue volumes receiving high prescribed dose levels in the course of radiotherapy. Planning target definition is, therefore, crucial to ensure favorable clinical outcomes. This is especially important for stereotactic body radiation therapy of lung cancers, characterized by high fractional doses and steep dose gradients. The shift in recent years from population-based to patient-specific treatment margins, as facilitated by the emergence of 4D medical imaging capabilities, is a major improvement. The commonly used motion-encompassing, or internal-target volume (ITV), target definition approach provides a high likelihood of coverage for the mobile tumor but inevitably exposes healthy tissue to high prescribed dose levels. The goal of this work was to generate an interpolated balanced planning target that takes into account both tumor coverage and normal tissue sparing from high prescribed dose levels, thereby improving on the ITV approach. Methods: For each 4DCT dataset, 4D deformable image registration was used to derive two bounding targets, namely, a 4D-intersection and a 4D-composite target which minimized normal tissue exposure to high prescribed dose levels and maximized tumor coverage, respectively. Through definition of an ''effective overlap volume histogram'' the authors derived an ''interpolated balanced planning target'' intended to balance normal tissue sparing from prescribed doses with tumor coverage. To demonstrate the dosimetric efficacy of the interpolated balanced planning target, the authors performed 4D treatment planning based on deformable image registration of 4D-CT data for five previously treated lung cancer patients. Two 4D plans were generated per patient, one based on the interpolated balanced planning target and the other based on the conventional ITV target. Plans were compared for tumor coverage and the degree of normal tissue sparing

  3. Identification of a calmodulin-binding domain in Sema4D that regulates its exodomain shedding in platelets

    PubMed Central

    Mou, Peipei; Zeng, Zhao; Li, Qiang; Liu, Xiaohui; Xin, Xiaoran; Wannemacher, Kenneth M.; Ruan, Changgeng; Li, Renhao; Brass, Lawrence F.

    2013-01-01

    Semaphorin 4D (Sema4D) is a transmembrane protein that supports contact-dependent amplification of platelet activation by collagen before being gradually cleaved by the metalloprotease ADAM17, as we have previously shown. Cleavage releases a soluble 120-kDa exodomain fragment for which receptors exist on platelets and endothelial cells. Here we have examined the mechanism that regulates Sema4D exodomain cleavage. The results show that the membrane-proximal cytoplasmic domain of Sema4D contains a binding site for calmodulin within the polybasic region Arg762-Lys779. Coprecipitation studies show that Sema4D and calmodulin are associated in resting platelets, forming a complex that dissociates upon platelet activation by the agonists that trigger Sema4D cleavage. Inhibiting calmodulin with W7 or introducing a membrane-permeable peptide corresponding to the calmodulin-binding site is sufficient to trigger the dissociation of Sema4D from calmodulin and initiate cleavage. Conversely, deletion of the calmodulin-binding site causes constitutive shedding of Sema4D. These results show that (1) Sema4D is a calmodulin-binding protein with a site of interaction in its membrane-proximal cytoplasmic domain, (2) platelet agonists cause dissociation of the calmodulin–Sema4D complex, and (3) dissociation of the complex is sufficient to trigger ADAM17-dependent cleavage of Sema4D, releasing a bioactive fragment. PMID:23564909

  4. ADULT AND CHILDREN'S EXPOSURE TO 2,4-D FROM MULTIPLE SOURCES AND PATHWAYS

    EPA Science Inventory

    In this study, we investigated the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide exposures of 135 preschool-aged children and their adult caregivers at 135 homes in North Carolina (NC) and Ohio (OH). Participants were randomly recruited from six NC and six OH counties. Monito...

  5. Inverse planning for four-dimensional (4D) volumetric modulated arc therapy

    SciTech Connect

    Ma Yunzhi; Chang, Daniel; Keall, Paul; Xie Yiaoqin; Park, Jae-yoon; Suh, Tae-Suk; Xing Lei

    2010-11-15

    Purpose: To develop a 4D volumetric modulated arc therapy (VMAT) inverse planning framework. Methods: 4D VMAT inverse planning aims to derive an aperture and weight modulated arc therapy treatment plan that optimizes the accumulated dose distribution from all gantry angles and breathing phases. Under an assumption that the gantry rotation and patient breathing are synchronized (i.e., there is a functional relationship between the phase of the patient breathing cycle and the beam angle), the authors compute the contribution from different respiration phases through the registration of the phased CT images. The accumulative dose distribution is optimized by iteratively adjusting the aperture shape and weight of each beam through the minimization of the planning objective function. For comparison, traditional 3D VMAT plans are also performed for the two cases and the performance of the proposed technique is demonstrated. Results: A framework for 4D VMAT inverse planning has been proposed. With the consideration of the extra dimension of time in VMAT, a tighter target margin can be achieved with a full duty cycle, which is otherwise not achievable simultaneously by either 3D VMAT optimization or gated VMAT. Conclusions: The 4D VMAT planning formulism proposed here provides useful insight on how the ''time'' dimension can be exploited in rotational arc therapy to maximally compensate for the intrafraction organ motion.

  6. PDE4D phosphorylation: A coincidence detector integrating multiple signaling pathways.

    PubMed

    Mika, Delphine; Conti, Marco

    2016-07-01

    In Eukaryotes, more than 100 different phosphodiesterase (PDE) proteins serve to fine-tune cyclic nucleotide (cAMP and cGMP) signals and contribute to specificity of signaling. In mammals, PDEs are divided into 11 families, of which PDE4 represents the largest family. Four genes (pde4a, pde4b, pde4c and pde4d) encode for this class of enzymes in mammals and give rise to more than 20 variants. Within this family of genes, PDE4D was discovered on the basis of its regulatory properties and its induction by hormones and cAMP. PDE4D has often been used as the prototype PDE4 and large body of work has been generated on the biochemical, pharmacological, and physiological properties of this enzyme. This review covers the regulation of PDE4D by phosphorylation, the impact of this regulation in the context of the structure of this protein, and the functional consequences of this complex pattern of posttranslational modifications. PMID:26562185

  7. Can exposure to prenatal sex hormones (2D:4D) predict cognitive reflection?

    PubMed

    Bosch-Domènech, Antoni; Brañas-Garza, Pablo; Espín, Antonio M

    2014-05-01

    The Cognitive Reflection Test (CRT) is a test introduced by Frederick (2005). The task is designed to measure the tendency to override an intuitive response that is incorrect and to engage in further reflection that leads to the correct response. The consistent sex differences in CRT performance may suggest a role for prenatal sex hormones. A now widely studied putative marker for relative prenatal testosterone is the second-to-fourth digit ratio (2D:4D). This paper tests to what extent 2D:4D, as a proxy for the prenatal ratio of testosterone/estrogens, can predict CRT scores in a sample of 623 students. After controlling for sex, we observe that a lower 2D:4D (reflecting a relative higher exposure to testosterone) is significantly associated with a higher number of correct answers. The result holds for both hands' 2D:4Ds. In addition, the effect appears to be stronger for females than for males. We also control for patience and math proficiency, which are significantly related to performance in the CRT. But the effect of 2D:4D on performance in CRT is not reduced with these controls, implying that these variables are not mediating the relationship between digit ratio and CRT.

  8. Clastogenicity of pentachlorophenol, 2,4-D and butachlor evaluated by Allium root tip test.

    PubMed

    Ateeq, Bushra; Abul Farah, M; Niamat Ali, M; Ahmad, Waseem

    2002-02-15

    The meristematic mitotic cells of Allium cepa is an efficient cytogenetic material for chromosome aberration assay on environmental pollutants. For assessing genotoxicity of pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (butachlor), 50% effective concentration (EC(50)), c-mitosis, stickiness, chromosome breaks and mitotic index (MI) were used as endpoints of genotoxicity. EC(50) values for PCP and butachlor are 0.73 and 5.13 ppm, respectively. 2,4-D evidently induced morphological changes at higher concentrations. Some changes like crochet hooks, c-tumours and broken roots were unique to 2,4-D at 5-20 ppm. No such abnormalities were found in PCP and butachlor treated groups, however, root deteriorated and degenerated at higher concentrations (<3 ppm) in PCP. MI in 2,4-D showed a low average of 14.32% followed by PCP (19.53%), while in butachlor it was recorded 71.6%, which is near to the control value. All chemicals induced chromosome aberrations at statistically significant level. The highest chromosome aberration frequency (11.90%) was recorded in PCP at 3 ppm. Large number of c-mitotic anaphases indicated that butachlor acts as potent spindle inhibitor, whereas, breaks, bridges, stickiness and laggards were most frequently found in PCP showing that it is a potent clastogen. PMID:11815249

  9. 77 FR 23135 - 2,4-D; Order Denying NRDC's Petition To Revoke Tolerances

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... and thyroid hormonal pathways and ecological effects. (63 FR 71542, 71544, December 28, 1998). The... battery of screening assays in a Federal Register Notice issued January 24, 2008 (73 FR 4216). EPA... October 21, 2009 for 67 chemicals including 2,4-D. (74 FR 54422, 54425). With regard to endocrine...

  10. Clastogenicity of pentachlorophenol, 2,4-D and butachlor evaluated by Allium root tip test.

    PubMed

    Ateeq, Bushra; Abul Farah, M; Niamat Ali, M; Ahmad, Waseem

    2002-02-15

    The meristematic mitotic cells of Allium cepa is an efficient cytogenetic material for chromosome aberration assay on environmental pollutants. For assessing genotoxicity of pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (butachlor), 50% effective concentration (EC(50)), c-mitosis, stickiness, chromosome breaks and mitotic index (MI) were used as endpoints of genotoxicity. EC(50) values for PCP and butachlor are 0.73 and 5.13 ppm, respectively. 2,4-D evidently induced morphological changes at higher concentrations. Some changes like crochet hooks, c-tumours and broken roots were unique to 2,4-D at 5-20 ppm. No such abnormalities were found in PCP and butachlor treated groups, however, root deteriorated and degenerated at higher concentrations (<3 ppm) in PCP. MI in 2,4-D showed a low average of 14.32% followed by PCP (19.53%), while in butachlor it was recorded 71.6%, which is near to the control value. All chemicals induced chromosome aberrations at statistically significant level. The highest chromosome aberration frequency (11.90%) was recorded in PCP at 3 ppm. Large number of c-mitotic anaphases indicated that butachlor acts as potent spindle inhibitor, whereas, breaks, bridges, stickiness and laggards were most frequently found in PCP showing that it is a potent clastogen.

  11. Noise filtering in thin-slice 4D cerebral CT perfusion scans

    NASA Astrophysics Data System (ADS)

    Mendrik, Adri"nne; Vonken, Evert-jan; Dankbaar, Jan-Willem; Prokop, Mathias; van Ginneken, Bram

    2010-03-01

    Patients suffering from cerebral ischemia or subarachnoid hemorrhage, undergo a 4D (3D+time) CT Perfusion (CTP) scan to assess the cerebral perfusion and a CT Angiography (CTA) scan to assess the vasculature. The aim of our research is to extract the vascular information from the CTP scan. This requires thin-slice CTP scans that suffer from a substantial amount of noise. Therefore noise reduction is an important prerequisite for further analysis. So far, the few noise filtering methods for 4D datasets proposed in literature deal with the temporal dimension as a 4th dimension similar to the 3 spatial dimensions, mixing temporal and spatial intensity information. We propose a bilateral noise reduction method based on time-intensity profile similarity (TIPS), which reduces noise while preserving temporal intensity information. TIPS was compared to 4D bilateral filtering on 10 patient CTP scans and, even though TIPS bilateral filtering is much faster, it results in better vessel visibility and higher image quality ranking (observer study) than 4D bilateral filtering.

  12. Geometric engineering, mirror symmetry and 6{d}_{(1,0)}to 4{d}_{(N=2)}

    NASA Astrophysics Data System (ADS)

    Del Zotto, Michele; Vafa, Cumrun; Xie, Dan

    2015-11-01

    We study compactification of 6 dimensional (1,0) theories on T 2. We use geometric engineering of these theories via F-theory and employ mirror symmetry technology to solve for the effective 4d N=2 geometry for a large number of the (1 ,0) theories including those associated with conformal matter. Using this we show that for a given 6d theory we can obtain many inequivalent 4d N=2 SCFTs. Some of these respect the global symmetries of the 6d theory while others exhibit SL(2 , ℤ) duality symmetry inherited from global diffeomorphisms of the T 2. This construction also explains the 6d origin of moduli space of 4d affine ADE quiver theories as flat ADE connections on T 2. Among the resulting 4 d N=2 CFTs we find theories whose vacuum geometry is captured by an LG theory (as opposed to a curve or a local CY geometry). We obtain arbitrary genus curves of class S with punctures from toroidal compactification of (1 , 0) SCFTs where the curve of the class S theory emerges through mirror symmetry. We also show that toroidal compactification of the little string version of these theories can lead to class S theories with no punctures on arbitrary genus Riemann surface.

  13. WELLTON GOVERNMENT CAMP, TEMPORARY RESIDENCE TYPE 4D. PLAN, SECTION, AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WELLTON GOVERNMENT CAMP, TEMPORARY RESIDENCE TYPE 4D. PLAN, SECTION, AND ELEVATIONS. Drawing 50-308-4566, dated July 16, 1949. U.S. Department of the Interior, Bureau of Reclamation, Yuma, Arizona - Wellton-Mohawk Irrigation System, Building No. 6 A-B (Duplex), 30651 & 30653 Wellton-Mohawk Drive, Wellton, Yuma County, AZ

  14. Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

    NASA Astrophysics Data System (ADS)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

    2015-03-01

    To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

  15. Mixing 4D-Equipped and Unequipped Aircraft in the Terminal Area

    NASA Technical Reports Server (NTRS)

    Tobias, L.; Erzberger, H.; Lee, H. Q.; Obrien, P. J.

    1984-01-01

    On-board 4D guidance systems, which predict and control the touchdown time of an aircraft to an accuracy of a few seconds throughout the descent, were developed and demonstrated in several flight test programs. However, in addition to refinements of the on board system, two important issues still need to be considered. First, in order to make effective use of these on-board systems, it is necessary to understand and develop the interactions of the airborne and air traffic control (ATC) system in the proposed advanced environment. Unless the total system is understood, the advanced on-board system may prove unusable from an ATC standpoint. Second, in planning for a future system in which all aircraft are 4D equipped, it is necessary to confront the transition situation in which some percentage of traffic must still be handled by conventional means. In terms of 4D, this means that some traffic must still be given radar vectors and speed clearances (that is, be spaced by conventional distance separation techniques), while the 4D-equipped aircraft need to be issued time assignments. These apparent differences are reconciled and efficient ATC operation is developed.

  16. Five cycles of selection for 2,4-D resistance in red clover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    2,4-D and other auxin-like mode of action herbicides are used to control broadleaf weeds in pastures. Unfortunately such herbicides also kill beneficial forage legumes in pastures. Although transgene-conferred herbicide-resistance is utilized in some crops, it is unlikely that transgenic breeding ap...

  17. Assimilation of DMSP/SSUSI UV data into IDA4D

    NASA Astrophysics Data System (ADS)

    Gelinas, L. J.; Bust, G. S.; Brinkman, D. G.; Straus, P. R.; Swartz, R. L.

    2014-12-01

    Ionospheric Data Assimilation Four-Dimensional (IDA4D) is a continuous-time, three-dimensional imaging algorithm that can produce 4D electron density specifications for various science investigations [e.g., Bust et al., 2007]. IDA4D is based on three-dimensional variational (3DVAR) data assimilation [Daley and Barker, 2001]. The algorithm combines various data sources and their associated error covariances with a background model (in this case the IRI) and its covariances to produce an ionospheric specification with formal uncertainties. IDA4D employs a Gauss- Markov Kalman filter technique similar to that used by operational assimilation models. The model can ingest a broad spectrum of data types that are either linearly or non-linearly related to electron density, including ground-based TEC, space-based TEC as measured by GPS occultation sensors and UV emissions associated with nightside recombination of O+. IDA4D has been undergoing testing at The Aerospace Corporation to determine its performance with respect to combinations of input data sets under different conditions (solar minimum, solar maximum, geomagnetic activity). The results presented here summarize the performance of IDA4D when UV data is ingested, both with and without additional TEC measurements. The UV data used in the study summarized here are 135.6 nm emissions measured the SSUSI instruments on F16 and F18 DMSP. We discuss the process by which UV data is ingested into IDA4D, including data binning, error estimation and correction of 135.6 nm contamination from mutual neutralization of O+ and O-. Model performance is then assessed using comparisons to various ground truth data, including ISR data, Jason VTEC, CNOF/S in-situ plasma density and ionosonde-derived NmF2 values. The results of this study show that UV data improves model performance, particularly when TEC data coverage is sparse. Bust, G. S., G. Crowley, T. W. Garner, T. L. Gaussiran II, R. W. Meggs, C. N. Mitchell, P. S. J. Spencer, P

  18. Evaluation of the Elekta Symmetry ™ 4D IGRT system by using a moving lung phantom

    NASA Astrophysics Data System (ADS)

    Shin, Hun-Joo; Kim, Shin-Wook; Kay, Chul Seung; Seo, Jae-Hyuk; Lee, Gi-Woong; Kang, Ki-Mun; Jang, Hong Seok; Kang, Young-nam

    2015-07-01

    Purpose: 4D cone-beam computed tomography (CBCT) is a beneficial tool for the treatment of movable tumors because it can help us to understand where the tumors are actually located and it has a precise treatment plan. However, general CBCT images have a limitation in that they cannot perfectly perform a sophisticated registration. On the other hand, the Symmetry TM 4D image-guided radiation therapy (IGRT) system of Elekta offers a 4D CBCT registration option. In this study, we evaluated the usefulness of Symmetry TM . Method and Materials: Planning CT images of the CIRS moving lung phantom were acquired 4D multi-detector CT (MDCT), and the images were sorted as 10 phases from 0% phase to 90% phase. The thickness of the CT images was 1 mm. Acquired MDCT images were transferred to the contouring software, and a virtual target was generated. A one-arc volumetric-modulated arc therapy (VMAT) plan was performed by using the treatment planning system on the virtual target. Finally, the movement of the phantom was verified by using the XVI Symmetry TM system. Results: The physical movement of the CIRS moving lung phantom was ±10.0 mm in the superiorinferior direction, ±1.0 mm in the lateral direction, and ±2.5 mm in the anterior-posterior direction. The movement of the phantom was measured from the 4D MDCT registration as ±10.2 mm in the superior-inferior direction, ±0.9 mm in the lateral direction, and ±2.45 mm in the anterior-posterior direction. The movement of the phantom was measured from the SymmetryTM registration as ±10.1 mm in the superior-inferior direction, ±0.9 mm in the lateral direction, and ±2.4 mm in the anterior-posterior direction. Conclusion: We confirmed that 4D CBCT is a beneficial tool for the treatment of movable tumors, and that the 4D registration of SymmetryTM can increase the precision of the registration when a movable tumor is the target of radiation treatment.

  19. Trauma-Related Altered States of Consciousness: Exploring the 4-D Model

    PubMed Central

    Frewen, Paul A.; Lanius, Ruth A.

    2014-01-01

    Frewen and Lanius (in press) recently articulated a 4-D model as a framework for classifying symptoms of posttraumatic stress into those that potentially occur within normal waking consciousness (NWC) versus those that intrinsically represent dissociative experiences of trauma-related altered states of consciousness (TRASC). Four dimensions were specified: time-memory, thought, body, and emotion. The 4-D model further hypothesizes that in traumatized persons, symptoms of TRASC, compared with NWC forms of distress, will be (a) observed less frequently; (b) less intercorrelated, especially as measured as moment-to-moment states; (c) observed more frequently in people with high dissociative symptomatology as measured independently; and (d) observed more often in people who have experienced repeated traumatization, particularly early developmental trauma. The aim of the present research was to begin to evaluate these 4 predictions of the 4-D model. Within a sample of 74 women with posttraumatic stress disorder (PTSD) primarily due to histories of childhood trauma, as well as within a 2nd sample of 504 undergraduates (384 females), the 1st 2 hypotheses of the 4-D model were supported. In addition, within the PTSD sample, the 3rd hypothesis was supported. However, inconsistent with the 4th hypothesis, severity of childhood trauma history was not strongly associated with TRASC. We conclude that the hypotheses articulated by the 4-D model were generally supported, although further research in different trauma-related disorders is needed, and the role of childhood trauma history in the etiology of TRASC requires further research. PMID:24650122

  20. Soil depth and temperature effects on microbial degradation of 2,4-D

    SciTech Connect

    Veeh, R.H.; Camper, A.K.; Inskeep, W.P.

    1996-01-01

    Numerous soil factors and climatic conditions affect the degradation rate of pesticides in soils. A major soil factor influencing herbicide degradation is the composition and abundance of the microbiota, which has been shown to vary considerably with soil depth. Another important variable affecting microbial growth and degradation kinetics is temperature. Soil samples from 0- to 30-, 30- to 60-, and 60- to 120-cm depths of two Montana soils were placed in reaction flasks and treated with {sup 14}C-labeled 2,4-D at representative field use rates at temperatures of 10, 17, and 24{degrees}C. A carrier gas was used to continuously evacuate evolved {sup 14}CO{sub 2} into NaOH traps as a measure of 2,4-D degradation. Comparisons of the effects of soil depth and temperature were made by fitting experimental data to both first-order and logistic kinetic models. Degradation rates of 2,4-D decreased significantly with increasing soil depth and were positively correlated with bacterial plate counts. Effects of temperature on degradation rate constants were adequately described using the Arrhenius equation. Degradation rates of 2,4-D and bacterial enumerations were positively correlated with changes in soil organic C as a function of soil depth. These results support the idea that changes in organic C with soil depth could be used as a parameter for estimating changes in degradation rate as a function of soil depth. Efforts to model the transport of 2,4-D in soils should account for variation in degradation rate as a function of soil depth and temperature. 46 refs., 4 figs., 3 tabs.

  1. 4D/RCS: a reference model architecture for intelligent unmanned ground vehicles

    NASA Astrophysics Data System (ADS)

    Albus, James S.

    2002-07-01

    4D/RCS consists of a multi-layered multi-resolutional hierarchy of computational nodes each containing elements of sensory processing (SP), world modeling (WM), value judgment (VJ), and behavior generation (BG). At the lower levels, these elements generate goal-seeking reactive behavior. At higher levels, they enable goal-defining deliberative behavior. At low levels, range in space and time is short and resolution is high. At high levels, distance and time are long and resolution is low. This enables high-precision fast-action response over short intervals of time and space at low levels, while long-range plans and abstract concepts are being formulated over broad regions of time and space at high levels. 4D/RCS closes feedback loops at every level. SP processes focus attention (i.e., window regions of space or time), group (i.e., segment regions into entities), compute entity attributes, estimate entity state, and assign entities to classes at every level. WM processes maintain a rich and dynamic database of knowledge about the world in the form of images, maps, entities, events, and relationships at every level. Other WM processes use that knowledge to generate estimates and predictions that support perception, reasoning, and planning at every level. 4D/RCS was developed for the Army Research Laboratory Demo III program. To date, only the lower levels of the 4D/RCS architecture have been fully implemented, but the results have been extremely positive. It seems clear that the theoretical basis of 4D/RCS is sound and the architecture is capable of being extended to support much higher levels of performance.

  2. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA.

  3. [Effects of EDTA on the Reductive Dechlorination of 2,4-D by Pd/Fe].

    PubMed

    Zhou, Hong-yi; Nie, Ya-zhong; Chen, Yong; Lei, Shuang-jian

    2016-02-15

    In Pd/Fe system, zero-valent iron (ZVI) passivation layer is easily formed on the particle surface during the catalytic reductive dechlorination of chlorinated organics, hindering further dechlorination of target contaminants. In this paper, the passivation layer on the Pd/Fe particle surfaces could be eliminated by the chelation of disodium edetate (EDTA) with Fe2+, Fe3+, making the reductive dechlorination continue. The experiment investigated the effects of EDTA addition manner and dosage, pH, Pd loading and temperature on dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by Pd/Fe. The conclusions can be summarized as follows: (1) Phenoxyacetic acid (PA) generation ratio reached 90. 7% within 20 min with EDTA concentration of 25.0 mmol x L(-1) and flow rate of 20 mL x h(-1), while it was only 74.5% after 210 min in the system without EDTA. (2) The EDTA could chelate the Fe2+ and Fe3+ generated from the process of 2,4-D dechlorination by Pd/Fe, preventing or slowing down the formation of passivation layer, and accelerating the reduction efficiency. (3) The appropriate experimental parameters for 2,4-D removal were as follows: EDTA flow rate of 20 mL x h(-1), CEDTA of 25.0 mmol x L(-1), Pd loading of 0.050%, 200 r x min(-1), pH 4.2 and 30.0 degrees C. The removal percentage of 20.0 mg x L(-1) 2,4-D reached nearly up to 100% within 210 min under these conditions. (4) The intermediates of 2, 4-D catalytic dechlorination included 2-chlorophenoxvacetic acid (2-CPA) and trace 4-chloronhenoxyacetic acid (4-CPA), and the end product was PA. PMID:27363149

  4. Development of an immunoassay for determination of 2,4-dichlorophenoxyacetic acid (2,4-D) based upon the recombinant Fab fragment of 2,4-D specific antibody

    NASA Astrophysics Data System (ADS)

    Nguyen, Van C.; Nguyen, Thi D. T.; Dau, Hung A.; Tham, Thu N.; Quyen, Dinh T.; Bachmman, Till; Schmid, Rolf D.

    2001-09-01

    To develop an immunoassay and further an immunosensor for 2,4-D based upon recombinant antibody, the Fab fragments of 2,4-D specific antibody were expressed in E. coli. Western blotting analysis of the periplasmic cell fractions shown that under the non-reducing condition only a single protein band at a molecular mass of 45-kDa, corresponding to the whole Fab fragment was detected. Antigen binding activity for 2,4-D was found only in the extract of cells bearing the 2,4-D plasmid. An immunoassay based on the competitive reaction of 2,4-D and enzyme tracer with 2,4-D Fab fragments immobilized on micro titer plates via rabbit anti-mouse IgC was developed. Using this assay, 2,4-D could be detected at concentration range of 0.5 (mu) g/1 to 10(mu) g/1. The center point of the 2,4-D test was found at a concentration of 5 (mu) g/l. The assay was applied for detection of 2,4-D in spiked orange samples, resulting in recovery rate of 90 percent. The immunoassay could be applied to monitor human exposure to 2,4-D from contamination in fruit samples.

  5. 4D-CT imaging of a volume influenced by respiratory motion on multi-slice CT.

    PubMed

    Pan, Tinsu; Lee, Ting-Yim; Rietzel, Eike; Chen, George T Y

    2004-02-01

    We propose a new scanning protocol for generating 4D-CT image data sets influenced by respiratory motion. A cine scanning protocol is used during data acquisition, and two registration methods are used to sort images into temporal phases. A volume is imaged in multiple acquisitions of 1 or 2 cm length along the cranial-caudal direction. In each acquisition, the scans are continuously acquired for a time interval greater than or equal to the average respiratory cycle plus the duration of the data for an image reconstruction. The x ray is turned off during CT table translation and the acquisition is repeated until the prescribed volume is completely scanned. The scanning for 20 cm coverage takes about 1 min with an eight-slice CT or 2 mins with a four-slice CT. After data acquisition, the CT data are registered into respiratory phases based on either an internal anatomical match or an external respiratory signal. The internal approach registers the data according to correlation of anatomy in the CT images between two adjacent locations in consecutive respiratory cycles. We have demonstrated the technique with ROIs placed in the region of diaphragm. The external approach registers the image data according to an externally recorded respiratory signal generated by the Real-Time Position Management (RPM) Respiratory Gating System (Varian Medical Systems, Palo Alto, CA). Compared with previously reported prospective or retrospective imaging of the respiratory motion with a single-slice or multi-slice CT, the 4D-CT method proposed here provides (1) a shorter scan time of three to six times faster than the single-slice CT with prospective gating; (2) a shorter scan time of two to four times improvement over a previously reported multi-slice CT implementation, and (3) images over all phases of a breathing cycle. We have applied the scanning and registration methods on phantom, animal and patients, and initial results suggest the applicability of both the scanning and the

  6. Impact of temporal probability in 4D dose calculation for lung tumors.

    PubMed

    Rouabhi, Ouided; Ma, Mingyu; Bayouth, John; Xia, Junyi

    2015-11-08

    The purpose of this study was to evaluate the dosimetric uncertainty in 4D dose calculation using three temporal probability distributions: uniform distribution, sinusoidal distribution, and patient-specific distribution derived from the patient respiratory trace. Temporal probability, defined as the fraction of time a patient spends in each respiratory amplitude, was evaluated in nine lung cancer patients. Four-dimensional computed tomography (4D CT), along with deformable image registration, was used to compute 4D dose incorporating the patient's respiratory motion. First, the dose of each of 10 phase CTs was computed using the same planning parameters as those used in 3D treatment planning based on the breath-hold CT. Next, deformable image registration was used to deform the dose of each phase CT to the breath-hold CT using the deformation map between the phase CT and the breath-hold CT. Finally, the 4D dose was computed by summing the deformed phase doses using their corresponding temporal probabilities. In this study, 4D dose calculated from the patient-specific temporal probability distribution was used as the ground truth. The dosimetric evaluation matrix included: 1) 3D gamma analysis, 2) mean tumor dose (MTD), 3) mean lung dose (MLD), and 4) lung V20. For seven out of nine patients, both uniform and sinusoidal temporal probability dose distributions were found to have an average gamma passing rate > 95% for both the lung and PTV regions. Compared with 4D dose calculated using the patient respiratory trace, doses using uniform and sinusoidal distribution showed a percentage difference on average of -0.1% ± 0.6% and -0.2% ± 0.4% in MTD, -0.2% ± 1.9% and -0.2% ± 1.3% in MLD, 0.09% ± 2.8% and -0.07% ± 1.8% in lung V20, -0.1% ± 2.0% and 0.08% ± 1.34% in lung V10, 0.47% ± 1.8% and 0.19% ± 1.3% in lung V5, respectively. We concluded that four-dimensional dose computed using either a uniform or sinusoidal temporal probability distribution can

  7. Population of anatomically variable 4D XCAT adult phantoms for imaging research and optimization

    SciTech Connect

    Segars, W. P.; Bond, Jason; Frush, Jack; Hon, Sylvia; Eckersley, Chris; Samei, E.; Williams, Cameron H.; Frush, D.; Feng Jianqiao; Tward, Daniel J.; Ratnanather, J. T.; Miller, M. I.

    2013-04-15

    Purpose: The authors previously developed the 4D extended cardiac-torso (XCAT) phantom for multimodality imaging research. The XCAT consisted of highly detailed whole-body models for the standard male and female adult, including the cardiac and respiratory motions. In this work, the authors extend the XCAT beyond these reference anatomies by developing a series of anatomically variable 4D XCAT adult phantoms for imaging research, the first library of 4D computational phantoms. Methods: The initial anatomy of each phantom was based on chest-abdomen-pelvis computed tomography data from normal patients obtained from the Duke University database. The major organs and structures for each phantom were segmented from the corresponding data and defined using nonuniform rational B-spline surfaces. To complete the body, the authors manually added on the head, arms, and legs using the original XCAT adult male and female anatomies. The structures were scaled to best match the age and anatomy of the patient. A multichannel large deformation diffeomorphic metric mapping algorithm was then used to calculate the transform from the template XCAT phantom (male or female) to the target patient model. The transform was applied to the template XCAT to fill in any unsegmented structures within the target phantom and to implement the 4D cardiac and respiratory models in the new anatomy. Each new phantom was refined by checking for anatomical accuracy via inspection of the models. Results: Using these methods, the authors created a series of computerized phantoms with thousands of anatomical structures and modeling cardiac and respiratory motions. The database consists of 58 (35 male and 23 female) anatomically variable phantoms in total. Like the original XCAT, these phantoms can be combined with existing simulation packages to simulate realistic imaging data. Each new phantom contains parameterized models for the anatomy and the cardiac and respiratory motions and can, therefore, serve

  8. 4D Near Real-Time Environmental Monitoring Using Highly Temporal LiDAR

    NASA Astrophysics Data System (ADS)

    Höfle, Bernhard; Canli, Ekrem; Schmitz, Evelyn; Crommelinck, Sophie; Hoffmeister, Dirk; Glade, Thomas

    2016-04-01

    The last decade has witnessed extensive applications of 3D environmental monitoring with the LiDAR technology, also referred to as laser scanning. Although several automatic methods were developed to extract environmental parameters from LiDAR point clouds, only little research has focused on highly multitemporal near real-time LiDAR (4D-LiDAR) for environmental monitoring. Large potential of applying 4D-LiDAR is given for landscape objects with high and varying rates of change (e.g. plant growth) and also for phenomena with sudden unpredictable changes (e.g. geomorphological processes). In this presentation we will report on the most recent findings of the research projects 4DEMON (http://uni-heidelberg.de/4demon) and NoeSLIDE (https://geomorph.univie.ac.at/forschung/projekte/aktuell/noeslide/). The method development in both projects is based on two real-world use cases: i) Surface parameter derivation of agricultural crops (e.g. crop height) and ii) change detection of landslides. Both projects exploit the "full history" contained in the LiDAR point cloud time series. One crucial initial step of 4D-LiDAR analysis is the co-registration over time, 3D-georeferencing and time-dependent quality assessment of the LiDAR point cloud time series. Due to the high amount of datasets (e.g. one full LiDAR scan per day), the procedure needs to be performed fully automatically. Furthermore, the online near real-time 4D monitoring system requires to set triggers that can detect removal or moving of tie reflectors (used for co-registration) or the scanner itself. This guarantees long-term data acquisition with high quality. We will present results from a georeferencing experiment for 4D-LiDAR monitoring, which performs benchmarking of co-registration, 3D-georeferencing and also fully automatic detection of events (e.g. removal/moving of reflectors or scanner). Secondly, we will show our empirical findings of an ongoing permanent LiDAR observation of a landslide (Gresten

  9. EarthScope imaging of 4D stress evolution of the San Andreas Fault System

    NASA Astrophysics Data System (ADS)

    Smith-Konter, B. R.; Del Pardo, C.

    2011-12-01

    EarthScope seismic and geodetic observations, combined with sophisticated computational models and powerful visualization tools, are now providing a critical ensemble of information about interseismic stressing rates along the San Andreas Fault System (SAFS). When combined with paleoseismic chronologies of earthquake ruptures spanning the last several hundreds of years, four-dimensional (4D) simulations of stress evolution spanning multiple earthquake cycles are now possible. To investigate stress variations at depth along the SAFS over multiple earthquake cycles, we use a 4D semi-analytic model that simulates interseismic strain accumulation, coseismic displacement, and post-seismic viscoelastic relaxation of the mantle. The model utilizes geologic estimates of fault locations and slip rates, as well as paleoseismic earthquake rupture histories, and is computed at a 500 m grid resolution to better resolve the sharp deformation gradients at creeping faults. Using EarthScope PBO and ALOS InSAR data, we tune the model locking depths and slip rates to compute the 4D stress accumulation within the seismogenic crust. 4D models show that stress accumulation and stress drop are a complex function of space and time. We use ParaView 3.10, an open-source multi-platform visualization package, for manipulation and visualization of 4D stress variations of fault segments at depth. We use ParaView to create a 3D meshed volume spanning a ~1000 x 1500 x 50 km region of the SAFS and present both volume and sliced views of stress from several viewpoints along the plate boundary. These models reveal pockets of stress concentrated at depth due to the interaction of neighboring fault segments and at fault segment branching junctions. We present several sensitivity tests that reveal the variation of stress at depth as a function of locking depth, slip rate, coefficient of friction, elastic plate thickness, and viscosity. These visualizations lay the groundwork for 4D time

  10. SU-E-J-187: Individually Optimized Contrast-Enhancement 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

    SciTech Connect

    Xue, M; Patel, K; Regine, W; Lane, B; D'Souza, W; Lu, W; Klahr, P

    2014-06-01

    Purpose: To study the feasibility of individually optimized contrastenhancement (CE) 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. To evaluate the image quality and contrast enhancement of tumor in the CE 4D-CT, compared to the clinical standard of CE 3D-CT and 4D-CT. Methods: In this IRB-approved study, each of the 7 PDA patients enrolled underwent 3 CT scans: a free-breathing 3D-CT with contrast (CE 3D-CT) followed by a 4D-CT without contrast (4D-CT) in the first study session, and a 4D-CT with individually synchronized contrast injection (CE 4D-CT) in the second study session. In CE 4D-CT, the time of full contrast injection was determined based on the time of peak enhancement for the test injection, injection rate, table speed, and longitudinal location and span of the pancreatic region. Physicians contoured both the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (end-of-exhalation for 4D-CT). The contrast between the tumor and normal pancreatic tissue was computed as the difference of the mean enhancement level of three 1 cm3 regions of interests in T and P, respectively. Wilcoxon rank sum test was used to statistically compare the scores and contrasts. Results: In qualitative evaluations, both CE 3D-CT and CE 4D-CT scored significantly better than 4D-CT (4.0 and 3.6 vs. 2.6). There was no significant difference between CE 3D-CT and CE 4D-CT. In quantitative evaluations, the contrasts between the tumor and the normal pancreatic parenchyma were 0.6±23.4, −2.1±8.0, and −19.6±28.8 HU, in CE 3D-CT, 4D-CT, and CE 4D-CT, respectively. Although not statistically significant, CE 4D-CT achieved better contrast enhancement between the tumor and the normal pancreatic parenchyma than both CE 3D-CT and 4DCT. Conclusion: CE 4D-CT achieved equivalent image quality and better contrast enhancement between tumor and normal pancreatic parenchyma than the clinical standard of CE 3D-CT and 4D-CT. This study was supported in part

  11. User-centred health design: reflections on D4D's experiences and challenges.

    PubMed

    Moody, Louise

    2014-01-01

    There is increasing recognition of the importance of user-centred design and testing in the healthcare technology domain. Challenges associated with user and stakeholder involvement in designing solutions for healthcare are recognized in the literature and need to be addressed to facilitate the development of new technology that is usable and acceptable to the end-user. The Devices for Dignity Health Technology Cooperative (D4D) has been involved in a range of technology development projects with an underpinning approach of addressing unmet needs through user involvement. This paper provides practical examples of some of the challenges that occur at different stages during a user-centred design process including ethical approval processes; stakeholder and user recruitment and involvement; eliciting needs from users regarding sensitive and personal issues; and interdisciplinary working. The paper will describe some of the strategies that have been employed by D4D to overcome these challenges and facilitate technology development.

  12. The epigenome, 4D nucleome and next-generation neuropsychiatric pharmacogenomics.

    PubMed

    Higgins, Gerald A; Allyn-Feuer, Ari; Handelman, Samuel; Sadee, Wolfgang; Athey, Brian D

    2015-01-01

    The 4D nucleome has the potential to render challenges in neuropsychiatric pharmacogenomics more tractable. The epigenome roadmap consortium has demonstrated the critical role that noncoding regions of the human genome play in determination of human phenotype. Chromosome conformation capture methods have revealed the 4D organization of the nucleus, bringing interactions between distant regulatory elements into close spatial proximity in a periodic manner. These functional interactions have the potential to elucidate mechanisms of CNS drug response and side effects that previously have been unrecognized. This perspective assesses recent advances likely to reveal novel pharmacodynamic regulatory pathways in human brain, charting a future new avenue of pharmacogenomics research, using the spatial and temporal architecture of the human epigenome as its foundation. PMID:26338265

  13. Coupled Ocean-Atmosphere 4D-Var: Formulation and Sensitivity Analysis Results

    NASA Astrophysics Data System (ADS)

    Ngodock, Hans; Carrier, Matthew; Xu, Liang; Amerault, Clark; Campbell, Tim; Rowley, Clark

    2016-04-01

    The US Navy is currently developing the first coupled ocean-atmosphere four-dimensional variational (4D-Var) data assimilation system to be used for short-term regional forecasting. This project merges the 4D-Var capabilities of the atmospheric component of the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS©) with the Navy Coastal Ocean Model (NCOM) through the Earth System Modeling Framework (ESMF). This will provide the coupled ocean-atmosphere forecast with a fully balanced analysis that accounts for all combined observations in both primary fluids (i.e. ocean and atmosphere). In this present work, the formulation of the system is presented in detail along with a series of adjoint sensitivity analysis results using the coupled ocean-atmosphere adjoint model. The sensitivity of the atmosphere (ocean) to each ocean (atmosphere) model variable is analyzed in detail in order to illustrate the usefulness of this approach in the coupled data assimilation system.

  14. The epigenome, 4D nucleome and next-generation neuropsychiatric pharmacogenomics.

    PubMed

    Higgins, Gerald A; Allyn-Feuer, Ari; Handelman, Samuel; Sadee, Wolfgang; Athey, Brian D

    2015-01-01

    The 4D nucleome has the potential to render challenges in neuropsychiatric pharmacogenomics more tractable. The epigenome roadmap consortium has demonstrated the critical role that noncoding regions of the human genome play in determination of human phenotype. Chromosome conformation capture methods have revealed the 4D organization of the nucleus, bringing interactions between distant regulatory elements into close spatial proximity in a periodic manner. These functional interactions have the potential to elucidate mechanisms of CNS drug response and side effects that previously have been unrecognized. This perspective assesses recent advances likely to reveal novel pharmacodynamic regulatory pathways in human brain, charting a future new avenue of pharmacogenomics research, using the spatial and temporal architecture of the human epigenome as its foundation.

  15. Chern-Simons actions and their gaugings in 4D, N =1 superspace

    NASA Astrophysics Data System (ADS)

    Becker, Katrin; Becker, Melanie; Linch, William D.; Robbins, Daniel

    2016-06-01

    We gauge the abelian hierarchy of tensor fields in 4D by a Lie algebra mathfrak{g} . The resulting non-abelian tensor hierarchy can be interpreted via a mathfrak{g} -equivariant chain complex. We lift this structure to N = 1 superspace by constructing superfield analogs for the tensor fields, along with covariant superfield strengths. Next we construct Chern-Simons actions, for both the bosonic and N = 1 cases, and note that the condition of gauge invariance can be presented cohomologically. Finally, we provide an explicit realization of these structures by dimensional reduction, for example by reducing the three-form of eleven-dimensional supergravity into a superspace with manifest 4D, N = 1 supersymmetry.

  16. 4D model generator of the human lung, "Lung4Cer".

    PubMed

    Kitaoka, Hiroko; Koc, Salim; Tetsumoto, Satoshi; Koumo, Satoshi; Hirata, Haruhiko; Kijima, Takashi

    2013-01-01

    We have developed a free software applications which generates 4D (= 3D + time) lung models for the purpose of studying lung anatomy, physiology, and pathophysiology. The coinage of 4C is originated from Japanese words, Catachi (= shape, structure) and Calacli (= machine, function). Lung4Cer makes 4D finite element models from the trachea to alveoli, which allow airflow simulation by means of computational fluid dynamics. Visualization of the generated models is expected to use a popular free software application, ParaView. There are several versions of Lung4Cer from basic lung morphology to advanced airflow computations simulating various clinical pulmonary function tests (PFT4Cer). All versions are designed so as to be operated on a common PC. Users can select model types and the element number according to their purposes and available computer resources.

  17. Crustal evolution of an ore district illustrated - 4D-animation from the Skellefte district, Sweden

    NASA Astrophysics Data System (ADS)

    Skyttä, Pietari

    2012-11-01

    This paper exemplifies how the dynamic crustal evolution within geologically complex areas, such as the Palaeoproterozoic VMS-hosting Skellefte district in northern Sweden, may be illustrated by 4D-animations. Furthermore, the paper gives a brief description on how the animation was constructed. The modeled steps through the geological evolution include crustal extension accommodated by normal faults, synchronous volcanism and VMS deposition, block rotations and erosion post-dating the volcanism, deposition of post-volcanic sediments and, finally, inversion of the early normal faults and the related development of upright folds. Specific emphasis is put on illustrating how the originally stratabound VMS sheets were transposed into contrasting geometries depending on erosional features and variations in the tectonic overprint. Summing up, 4D-animations provide a powerful tool for sharing the scientific results and for use in educational purposes.

  18. User-centred health design: reflections on D4D's experiences and challenges.

    PubMed

    Moody, Louise

    2014-01-01

    There is increasing recognition of the importance of user-centred design and testing in the healthcare technology domain. Challenges associated with user and stakeholder involvement in designing solutions for healthcare are recognized in the literature and need to be addressed to facilitate the development of new technology that is usable and acceptable to the end-user. The Devices for Dignity Health Technology Cooperative (D4D) has been involved in a range of technology development projects with an underpinning approach of addressing unmet needs through user involvement. This paper provides practical examples of some of the challenges that occur at different stages during a user-centred design process including ethical approval processes; stakeholder and user recruitment and involvement; eliciting needs from users regarding sensitive and personal issues; and interdisciplinary working. The paper will describe some of the strategies that have been employed by D4D to overcome these challenges and facilitate technology development. PMID:26453037

  19. 4D traction force microscopy reveals asymmetric cortical forces in migrating Dictyostelium cells.

    PubMed

    Delanoë-Ayari, H; Rieu, J P; Sano, M

    2010-12-10

    We present a 4D (x; y; z; t) force map of Dictyostelium cells crawling on a soft gel substrate. Vertical forces are of the same order as the tangential ones. The cells pull the substratum upward along the cell, medium, or substratum contact line and push it downward under the cell except for the pseudopods. We demonstrate quantitatively that the variations in the asymmetry in cortical forces correlates with the variations of the direction and speed of cell displacement. PMID:21231559

  20. Robust segmentation of 4D cardiac MRI-tagged images via spatio-temporal propagation

    NASA Astrophysics Data System (ADS)

    Qian, Zhen; Huang, Xiaolei; Metaxas, Dimitris N.; Axel, Leon

    2005-04-01

    In this paper we present a robust method for segmenting and tracking cardiac contours and tags in 4D cardiac MRI tagged images via spatio-temporal propagation. Our method is based on two main techniques: the Metamorphs Segmentation for robust boundary estimation, and the tunable Gabor filter bank for tagging lines enhancement, removal and myocardium tracking. We have developed a prototype system based on the integration of these two techniques, and achieved efficient, robust segmentation and tracking with minimal human interaction.

  1. Model-driven physiological assessment of the mitral valve from 4D TEE

    NASA Astrophysics Data System (ADS)

    Voigt, Ingmar; Ionasec, Razvan Ioan; Georgescu, Bogdan; Houle, Helene; Huber, Martin; Hornegger, Joachim; Comaniciu, Dorin

    2009-02-01

    Disorders of the mitral valve are second most frequent, cumulating 14 percent of total number of deaths caused by Valvular Heart Disease each year in the United States and require elaborate clinical management. Visual and quantitative evaluation of the valve is an important step in the clinical workflow according to experts as knowledge about mitral morphology and dynamics is crucial for interventional planning. Traditionally this involves examination and metric analysis of 2D images comprising potential errors being intrinsic to the method. Recent commercial solutions are limited to specific anatomic components, pathologies and a single phase of cardiac 4D acquisitions only. This paper introduces a novel approach for morphological and functional quantification of the mitral valve based on a 4D model estimated from ultrasound data. A physiological model of the mitral valve, covering the complete anatomy and eventual shape variations, is generated utilizing parametric spline surfaces constrained by topological and geometrical prior knowledge. The 4D model's parameters are estimated for each patient using the latest discriminative learning and incremental searching techniques. Precise evaluation of the anatomy using model-based dynamic measurements and advanced visualization are enabled through the proposed approach in a reliable, repeatable and reproducible manner. The efficiency and accuracy of the method is demonstrated through experiments and an initial validation based on clinical research results. To the best of our knowledge this is the first time such a patient specific 4D mitral valve model is proposed, covering all of the relevant anatomies and enabling to model the common pathologies at once.

  2. Automated contour mapping using sparse volume sampling for 4D radiation therapy

    SciTech Connect

    Chao Ming; Schreibmann, Eduard; Li Tianfang; Wink, Nicole; Xing Lei

    2007-10-15

    The purpose of this work is to develop a novel strategy to automatically map organ contours from one phase of respiration to all other phases on a four-dimensional computed tomography (4D CT). A region of interest (ROI) was manually delineated by a physician on one phase specific image set of a 4D CT. A number of cubic control volumes of the size of {approx}1 cm were automatically placed along the contours. The control volumes were then collectively mapped to the next phase using a rigid transformation. To accommodate organ deformation, a model-based adaptation of the control volume positions was followed after the rigid mapping procedure. This further adjustment of control volume positions was performed by minimizing an energy function which balances the tendency for the control volumes to move to their correspondences with the desire to maintain similar image features and shape integrity of the contour. The mapped ROI surface was then constructed based on the central positions of the control volumes using a triangulated surface construction technique. The proposed technique was assessed using a digital phantom and 4D CT images of three lung patients. Our digital phantom study data indicated that a spatial accuracy better than 2.5 mm is achievable using the proposed technique. The patient study showed a similar level of accuracy. In addition, the computational speed of our algorithm was significantly improved as compared with a conventional deformable registration-based contour mapping technique. The robustness and accuracy of this approach make it a valuable tool for the efficient use of the available spatial-tempo information for 4D simulation and treatment.

  3. Treatment of 2,4-D, mecoprop, and dicamba using membrane bioreactor technology.

    PubMed

    Ghoshdastidar, Avik J; Tong, Anthony Z

    2013-08-01

    Phenoxyacetic and benzoic acid herbicides are widely used agricultural, commercial, and domestic pesticides. As a result of high water solubility, mobility, and persistence, 2,4-dichlorophenoxyacetic acid (2,4-D), methylchlorophenoxypropionic acid (mecoprop), and 3,6-dichloro-2-methoxybenzoic acid (dicamba) have been detected in surface and waste waters across Canada. As current municipal wastewater treatment plants do not specifically address chronic, trace levels of contaminants like pesticides, an urgent need exists for an efficient, environmentally friendly means of breaking down these toxic herbicides. A commercially available herbicide mix, WeedEx, containing 2,4-D, mecoprop, and dicamba, was subjected to treatment using membrane bioreactor (MBR) technology. The three herbicides, in simulated wastewater with a chemical oxygen demand of 745 mg/L, were introduced to the MBR at concentrations ranging from 300 μg/L to 3.5 mg/L. Herbicides and biodegradation products were extracted from MBR effluent using solid-phase extraction followed by detection using high-performance liquid chromatography coupled with mass spectrometry. 2,4-D was reduced by more than 99.0 % within 12 days. Mecoprop and dicamba were more persistent and reduced by 69.0 and 75.4 %, respectively, after 112 days of treatment. Half-lives of 2,4-D, mecoprop and dicamba during the treatment were determined to be 1.9, 10.5, and 28.3 days, respectively. Important water quality parameters of the effluent such as dissolved oxygen, pH, ammonia, chemical oxygen demand, etc. were measured daily. MBR was demonstrated to be an environmentally friendly, compact, and efficient method for the treatment of toxic phenoxyacetic and benzoic acid herbicides. PMID:23361178

  4. 4D atlas of the mouse embryo for precise morphological staging.

    PubMed

    Wong, Michael D; van Eede, Matthijs C; Spring, Shoshana; Jevtic, Stefan; Boughner, Julia C; Lerch, Jason P; Henkelman, R Mark

    2015-10-15

    After more than a century of research, the mouse remains the gold-standard model system, for it recapitulates human development and disease and is quickly and highly tractable to genetic manipulations. Fundamental to the power and success of using a mouse model is the ability to stage embryonic mouse development accurately. Past staging systems were limited by the technologies of the day, such that only surface features, visible with a light microscope, could be recognized and used to define stages. With the advent of high-throughput 3D imaging tools that capture embryo morphology in microscopic detail, we now present the first 4D atlas staging system for mouse embryonic development using optical projection tomography and image registration methods. By tracking 3D trajectories of every anatomical point in the mouse embryo from E11.5 to E14.0, we established the first 4D atlas compiled from ex vivo 3D mouse embryo reference images. The resulting 4D atlas comprises 51 interpolated 3D images in this gestational range, resulting in a temporal resolution of 72 min. From this 4D atlas, any mouse embryo image can be subsequently compared and staged at the global, voxel and/or structural level. Assigning an embryonic stage to each point in anatomy allows for unprecedented quantitative analysis of developmental asynchrony among different anatomical structures in the same mouse embryo. This comprehensive developmental data set offers developmental biologists a new, powerful staging system that can identify and compare differences in developmental timing in wild-type embryos and shows promise for localizing deviations in mutant development.

  5. Hyperspectral lidar in non-destructive 4D monitoring of climate variables

    NASA Astrophysics Data System (ADS)

    Kaasalainen, S.; Hakala, T.; Nevalainen, O.; Puttonen, E.; Anttila, K.

    2014-09-01

    The first applications of a prototype 8-channel full waveform active hyperspectral lidar (HSL) show a possibility to determine various target 3D characteristics with remote observations. The results open up a prospect for four-dimensional (4D - a three dimensional target representation with time as a fourth dimension) monitoring of important climate variables, such as those related to tree physiology or snow pollution.

  6. 4D microscope-integrated OCT improves accuracy of ophthalmic surgical maneuvers

    NASA Astrophysics Data System (ADS)

    Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Shen, Liangbo; Todorich, Bozho; Shieh, Christine; Kuo, Anthony; Toth, Cynthia; Izatt, Joseph A.

    2016-03-01

    Ophthalmic surgeons manipulate micron-scale tissues using stereopsis through an operating microscope and instrument shadowing for depth perception. While ophthalmic microsurgery has benefitted from rapid advances in instrumentation and techniques, the basic principles of the stereo operating microscope have not changed since the 1930's. Optical Coherence Tomography (OCT) has revolutionized ophthalmic imaging and is now the gold standard for preoperative and postoperative evaluation of most retinal and many corneal procedures. We and others have developed initial microscope-integrated OCT (MIOCT) systems for concurrent OCT and operating microscope imaging, but these are limited to 2D real-time imaging and require offline post-processing for 3D rendering and visualization. Our previously presented 4D MIOCT system can record and display the 3D surgical field stereoscopically through the microscope oculars using a dual-channel heads-up display (HUD) at up to 10 micron-scale volumes per second. In this work, we show that 4D MIOCT guidance improves the accuracy of depth-based microsurgical maneuvers (with statistical significance) in mock surgery trials in a wet lab environment. Additionally, 4D MIOCT was successfully performed in 38/45 (84%) posterior and 14/14 (100%) anterior eye human surgeries, and revealed previously unrecognized lesions that were invisible through the operating microscope. These lesions, such as residual and potentially damaging retinal deformation during pathologic membrane peeling, were visualized in real-time by the surgeon. Our integrated system provides an enhanced 4D surgical visualization platform that can improve current ophthalmic surgical practice and may help develop and refine future microsurgical techniques.

  7. Unintended effects of the herbicides 2,4-D and dicamba on lady beetles.

    PubMed

    Freydier, Laurène; Lundgren, Jonathan G

    2016-08-01

    Weed resistance to glyphosate and development of new GM crops tolerant to 2,4-dichlorophenoxyacetic acid (2,4-D) and dicamba is expected to lead to increased use of these herbicides in cropland. The lady beetle, Coleomegilla maculata is an important beneficial insect in cropland that is commonly used as an indicator species in safety evaluations of pesticides. Here, we examined the lethal and non-lethal effects of 2,4-D and dicamba active ingredients and commercial formulations to this lady beetle species, and tested for synergistic effects of the herbicides. Second instars of lady beetles were exposed to an experimental treatment, and their mortality, development, weight, sex ratio, fecundity, and mobility was evaluated. Using similar methods, a dose-response study was conducted on 2,4-D with and without dicamba. The commercial formulation of 2,4-D was highly lethal to lady beetle larvae; the LC90 of this herbicide was 13 % of the label rate. In this case, the "inactive" ingredients were a key driver of the toxicity. Dicamba active ingredient significantly increased lady beetle mortality and reduced their body weight. The commercial formulations of both herbicides reduced the proportion of males in the lady beetle population. The herbicides when used together did not act synergistically in their toxicity toward lady beetles versus when the chemistries were used independently. Our work shows that herbicide formulations can cause both lethal and sublethal effects on non-target, beneficial insects, and these effects are sometimes driven by the "inactive" ingredients. The field-level implications of shifts in weed management practices on insect management programs should receive further attention. PMID:27282375

  8. 4D offline PET-based treatment verification in scanned ion beam therapy: a phantom study

    NASA Astrophysics Data System (ADS)

    Kurz, Christopher; Bauer, Julia; Unholtz, Daniel; Richter, Daniel; Stützer, Kristin; Bert, Christoph; Parodi, Katia

    2015-08-01

    At the Heidelberg Ion-Beam Therapy Center, patient irradiation with scanned proton and carbon ion beams is verified by offline positron emission tomography (PET) imaging: the {β+} -activity measured within the patient is compared to a prediction calculated on the basis of the treatment planning data in order to identify potential delivery errors. Currently, this monitoring technique is limited to the treatment of static target structures. However, intra-fractional organ motion imposes considerable additional challenges to scanned ion beam radiotherapy. In this work, the feasibility and potential of time-resolved (4D) offline PET-based treatment verification with a commercial full-ring PET/CT (x-ray computed tomography) device are investigated for the first time, based on an experimental campaign with moving phantoms. Motion was monitored during the gated beam delivery as well as the subsequent PET acquisition and was taken into account in the corresponding 4D Monte-Carlo simulations and data evaluation. Under the given experimental conditions, millimeter agreement between the prediction and measurement was found. Dosimetric consequences due to the phantom motion could be reliably identified. The agreement between PET measurement and prediction in the presence of motion was found to be similar as in static reference measurements, thus demonstrating the potential of 4D PET-based treatment verification for future clinical applications.

  9. Digit ratios (2D:4D), postnatal testosterone and eye contact in toddlers.

    PubMed

    Saenz, Janet; Alexander, Gerianne M

    2013-09-01

    Previous research has shown an association between eye contact and prenatal testosterone measured in amniocenteses samples. The purpose of this study was to test the association between eye contact and prenatal androgen action measured via second to fourth digit ratios (2D:4D ratios), and to explore the relationship between eye contact and postnatal testosterone levels. Participants included 72 children, between the ages of 18 and 24 months, and their parents. Salivary testosterone levels were obtained when children were 3-months old. At 18-months, 2D:4D ratios were measured and parent-child dyads participated in an 8-min play session that was recorded and later coded for duration and frequency of eye contact. Results indicated that larger 2D:4D ratios (indicative of lower androgen levels) significantly predicted longer duration and more frequency of eye contact, while postnatal testosterone levels were unrelated to eye contact. These novel findings suggest prenatal androgens may influence the emergence of social development.

  10. The Role of 4D Ultrasound in the Assessment of Fetal Behaviour

    PubMed Central

    Lebit, Dr. Florentina-Daniela; Vladareanu, Professor Dr. Radu

    2011-01-01

    ABSTRACT Fetal behavior is defined as any fetal action seen by the mother or fetus diagnosed by objective methods such as cardiotocography (CTG) or ultrasound. Analysis of the dynamics of the fetal behavior with morphological studies has lead to the conclusion that fetal behavior patterns are directly reflecting development and maturation of the central nervous system. The assessment of fetal behavior by 4D ultrasound could allow distinction between normal and abnormal fetal behavior patterns which might make possible the early recognition of fetal brain impairment. Aim: Assessment of fetal movements throughout the pregnancy using 4D ultrasound. Material and Method: The study group included 144 healthy pregnant women with single pregnancies between 7-38 weeks of gestation. For the first trimester of pregnancy we assessed eight types of fetal movements and for the second and third trimesters 14 types of fetal movements and facial expressions. The analyzed parameters for each trimester of pregnancy can be used for performing antenatal neurodevelopment test, used the first time by Professor Kurjak. Results: After 15-20 minutes 4D ultrasound examination, we found a pattern of fetal behavior for each trimester of pregnancy. Conclusions: Dynamic evaluation of fetal behavior reflects directly the processes of maturation and development of the central nervous system. This can make the difference between normal and abnormal brain development and may be used for early diagnosis of neurological disorders that become manifest in perinatal and postnatal periods. PMID:22205894

  11. Real-time volume rendering of 4D image using 3D texture mapping

    NASA Astrophysics Data System (ADS)

    Hwang, Jinwoo; Kim, June-Sic; Kim, Jae Seok; Kim, In Young; Kim, Sun Il

    2001-05-01

    Four dimensional image is 3D volume data that varies with time. It is used to express deforming or moving object in virtual surgery of 4D ultrasound. It is difficult to render 4D image by conventional ray-casting or shear-warp factorization methods because of their time-consuming rendering time or pre-processing stage whenever the volume data are changed. Even 3D texture mapping is used, repeated volume loading is also time-consuming in 4D image rendering. In this study, we propose a method to reduce data loading time using coherence between currently loaded volume and previously loaded volume in order to achieve real time rendering based on 3D texture mapping. Volume data are divided into small bricks and each brick being loaded is tested for similarity to one which was already loaded in memory. If the brick passed the test, it is defined as 3D texture by OpenGL functions. Later, the texture slices of the brick are mapped into polygons and blended by OpenGL blending functions. All bricks undergo this test. Continuously deforming fifty volumes are rendered in interactive time with SGI ONYX. Real-time volume rendering based on 3D texture mapping is currently available on PC.

  12. Data assimilation (4D-VAR) to forecast flood in shallow-waters with sediment erosion

    NASA Astrophysics Data System (ADS)

    Bélanger, Eric; Vincent, Alain

    2005-01-01

    In this paper, the four-dimensional variational data assimilation technique (4D-VAR) is presented as a tool to forecast floods. Our study is limited to purely hydrological flows and supposes that the weather, here a big rain, has been already forecasted by meteorological services. The technique consists in minimizing, in the sense of Lagrange, the cost function: a measure of the difference between calculated data and available observations, here the water level. This is done under constraints that are the equations of the physical model. In our case, we modified the shallow-water equations to include a simplified sediment transport model. The steepest descent algorithm is then used to find the minimum. This is made possible because we can compute analytically the gradient of the cost function by using the adjoint equations of the model. As an application of the 4D-VAR technique, the overflowing of the Chicoutimi River at the Chute-Garneau dam, during the 1996 flood, is investigated. It is found that the 4D-VAR method reduces the error in the water height forecast even when the erosion model is not activated. In terms of Lyapunov exponents, we estimate the predictability horizon of such an event to be about half-an-hour after a big rain. However, this limit of predictability can be increased by using more observations or by using a finer computational grid.

  13. Improvement of pyrazolo[3,4-d]pyrimidines pharmacokinetic properties: nanosystem approaches for drug delivery

    PubMed Central

    Vignaroli, Giulia; Calandro, Pierpaolo; Zamperini, Claudio; Coniglio, Federica; Iovenitti, Giulia; Tavanti, Matteo; Colecchia, David; Dreassi, Elena; Valoti, Massimo; Schenone, Silvia; Chiariello, Mario; Botta, Maurizio

    2016-01-01

    Pyrazolo[3,4-d]pyrimidines are a class of compounds with a good activity against several cancer cell lines. Despite the promising anticancer activity, these molecules showed a poor aqueous solubility. This issue could threat the future development of pyrazolo[3,4-d]pyrimidines as clinical drug candidates. With the aim of improving their solubility profile and consequently their pharmacokinetic properties, we have chosen four compounds (1–4) on the base of their anti-neuroblastoma activity and we have developed albumin nanoparticles and liposomes for the selected candidates. Albumin nanoparticles and liposomes were prepared and characterized regarding size and ζ-potential distribution, polidispersity index, entrapment efficiency and activity against SH-SY5Y human neuroblastoma cell line. The most promising nanosystem, namely LP-2, was chosen to perform further studies: confocal microscopy, stability and drug release in physiological conditions, and biodistribution. Altogether, the obtained data strongly indicate that the encapsulation of pyrazolo[3,4-d]pyrimidines in liposomes represent an effective method to overcome the poor water solubility. PMID:26898318

  14. Global structure of regular tori in a generic 4D symplectic map

    NASA Astrophysics Data System (ADS)

    Lange, S.; Richter, M.; Onken, F.; Bäcker, A.; Ketzmerick, R.

    2014-06-01

    For the case of generic 4d symplectic maps with a mixed phase space, we investigate the global organization of regular tori. For this, we compute elliptic 1-tori of two coupled standard maps and display them in a 3d phase-space slice. This visualizes how all regular 2-tori are organized around a skeleton of elliptic 1-tori in the 4d phase space. The 1-tori occur in two types of one-parameter families: (α) Lyapunov families emanating from elliptic-elliptic periodic orbits, which are observed to exist even far away from them and beyond major resonance gaps, and (β) families originating from rank-1 resonances. At resonance gaps of both types of families either (i) periodic orbits exist, similar to the Poincaré-Birkhoff theorem for 2d maps, or (ii) the family may form large bends. In combination, these results allow for describing the hierarchical structure of regular tori in the 4d phase space analogously to the islands-around-islands hierarchy in 2d maps.

  15. Automated Lung Segmentation and Image Quality Assessment for Clinical 3-D/4-D-Computed Tomography

    PubMed Central

    Li, Guang

    2014-01-01

    4-D-computed tomography (4DCT) provides not only a new dimension of patient-specific information for radiation therapy planning and treatment, but also a challenging scale of data volume to process and analyze. Manual analysis using existing 3-D tools is unable to keep up with vastly increased 4-D data volume, automated processing and analysis are thus needed to process 4DCT data effectively and efficiently. In this paper, we applied ideas and algorithms from image/signal processing, computer vision, and machine learning to 4DCT lung data so that lungs can be reliably segmented in a fully automated manner, lung features can be visualized and measured on the fly via user interactions, and data quality classifications can be computed in a robust manner. Comparisons of our results with an established treatment planning system and calculation by experts demonstrated negligible discrepancies (within ±2%) for volume assessment but one to two orders of magnitude performance enhancement. An empirical Fourier-analysis-based quality measure-delivered performances closely emulating human experts. Three machine learners are inspected to justify the viability of machine learning techniques used to robustly identify data quality of 4DCT images in the scalable manner. The resultant system provides a toolkit that speeds up 4-D tasks in the clinic and facilitates clinical research to improve current clinical practice. PMID:25621194

  16. 4D offline PET-based treatment verification in scanned ion beam therapy: a phantom study.

    PubMed

    Kurz, Christopher; Bauer, Julia; Unholtz, Daniel; Richter, Daniel; Stützer, Kristin; Bert, Christoph; Parodi, Katia

    2015-08-21

    At the Heidelberg Ion-Beam Therapy Center, patient irradiation with scanned proton and carbon ion beams is verified by offline positron emission tomography (PET) imaging: the β+-activity measured within the patient is compared to a prediction calculated on the basis of the treatment planning data in order to identify potential delivery errors. Currently, this monitoring technique is limited to the treatment of static target structures. However, intra-fractional organ motion imposes considerable additional challenges to scanned ion beam radiotherapy. In this work, the feasibility and potential of time-resolved (4D) offline PET-based treatment verification with a commercial full-ring PET/CT (x-ray computed tomography) device are investigated for the first time, based on an experimental campaign with moving phantoms. Motion was monitored during the gated beam delivery as well as the subsequent PET acquisition and was taken into account in the corresponding 4D Monte-Carlo simulations and data evaluation. Under the given experimental conditions, millimeter agreement between the prediction and measurement was found. Dosimetric consequences due to the phantom motion could be reliably identified. The agreement between PET measurement and prediction in the presence of motion was found to be similar as in static reference measurements, thus demonstrating the potential of 4D PET-based treatment verification for future clinical applications. PMID:26237315

  17. Sema4d is required for the development of the hindbrain boundary and skeletal muscle in zebrafish

    SciTech Connect

    Yang, Jie; Zeng, Zhen; Wei, Juncheng; Jiang, Lijun; Ma, Quanfu; Wu, Mingfu; Huang, Xiaoyuan; Ye, Shuangmei; Li, Ye; Ma, Ding; Gao, Qinglei

    2013-04-05

    Highlights: ► Sema4d was expressed at all developmental stages of zebrafish. ► Knockdown of sema4d in embryos resulted in defects in the hindbrain and the trunk structure. ► Knockdown of sema4d in embryos upregulated the expression of three hindbrain rhombomere markers. ► Knockdown of sema4d in embryos increased the expression of myogenic regulatory factors. ► Knockdown of sema4d in embryos resulted in an obvious increase of cell apoptosis. -- Abstract: Semaphorin4d (SEMA4D), also known as CD100, an oligodendrocyte secreted R-Ras GTPase-activating protein (GAP), affecting axonal growth is involved in a range of processes including cell adhesion, motility, angiogenesis, immune responses and tumour progression. However, its actual physiological mechanisms and its role in development remain unclear. This study has focused on the role of sema4d in the development and expression patterns in zebrafish embryos and the effect of its suppression on development using sema4d-specific antisense morpholino-oligonucleotides. In this study the knockdown of sema4d, expressed at all developmental stages, lead to defects in the hindbrain and trunk structure of zebrafish embryos. In addition, these phenotypes appeared to be associated with the abnormal expression of three hindbrain rhombomere boundary markers, wnt1, epha4a and foxb1.2, and two myogenic regulatory factors, myod and myog. Further, a notable increase of cell apoptosis appeared in the sema4d knockdown embryos, while no obvious reduction in cell proliferation was observed. Collectively, these data suggest that sema4d plays an important role in the development of the hindbrain and skeletal muscle.

  18. Factors Influencing Dislodgeable 2, 4-D Plant Residues from Hybrid Bermudagrass (Cynodon dactylon L. x C. transvaalensis) Athletic Fields.

    PubMed

    Jeffries, Matthew D; Gannon, Travis W; Brosnan, James T; Ahmed, Khalied A; Breeden, Gregory K

    2016-01-01

    Research to date has confirmed 2,4-D residues may dislodge from turfgrass; however, experiments have not been conducted on hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis), the most common athletic field turfgrass in subtropical climates. More specifically, previous research has not investigated the effect of post-application irrigation on dislodgeable 2,4-D residues from hybrid bermudagrass and across turfgrass species, research has been nondescript regarding sample time within a d (TWD) or conducted in the afternoon when the turfgrass canopy is dry, possibly underestimating potential for dislodgement. The effect of irrigation and TWD on 2,4-D dislodgeability was investigated. Dislodgeable 2,4-D amine was reduced > 300% following irrigation. From 2 to 7 d after treatment (DAT), ≤ 0.5% of applied 2,4-D was dislodged from irrigated turfgrass, while ≤ 2.3% of applied 2,4-D was dislodged when not irrigated. 2,4-D dislodgeability decreased as TWD increased. Dislodgeable 2,4-D residues declined to < 0.1% of the applied at 1 DAT- 13:00, and increased to 1 to 3% of the applied 2 DAT- 5:00, suggesting 2,4-D re-suspended on treated turfgrass vegetation overnight. In conclusion, irrigating treated turfgrass reduced dislodgeable 2,4-D. 2,4-D dislodgeability increased as TWD decreased, which was attributed to non-precipitation climatic conditions favoring turfgrass canopy wetness. This research will improve turfgrass management practices and research designed to minimize human 2,4-D exposure. PMID:26863005

  19. Factors Influencing Dislodgeable 2, 4-D Plant Residues from Hybrid Bermudagrass (Cynodon dactylon L. x C. transvaalensis) Athletic Fields

    PubMed Central

    Ahmed, Khalied A.; Breeden, Gregory K.

    2016-01-01

    Research to date has confirmed 2,4-D residues may dislodge from turfgrass; however, experiments have not been conducted on hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis), the most common athletic field turfgrass in subtropical climates. More specifically, previous research has not investigated the effect of post-application irrigation on dislodgeable 2,4-D residues from hybrid bermudagrass and across turfgrass species, research has been nondescript regarding sample time within a d (TWD) or conducted in the afternoon when the turfgrass canopy is dry, possibly underestimating potential for dislodgement. The effect of irrigation and TWD on 2,4-D dislodgeability was investigated. Dislodgeable 2,4-D amine was reduced > 300% following irrigation. From 2 to 7 d after treatment (DAT), ≤ 0.5% of applied 2,4-D was dislodged from irrigated turfgrass, while ≤ 2.3% of applied 2,4-D was dislodged when not irrigated. 2,4-D dislodgeability decreased as TWD increased. Dislodgeable 2,4-D residues declined to < 0.1% of the applied at 1 DAT– 13:00, and increased to 1 to 3% of the applied 2 DAT– 5:00, suggesting 2,4-D re-suspended on treated turfgrass vegetation overnight. In conclusion, irrigating treated turfgrass reduced dislodgeable 2,4-D. 2,4-D dislodgeability increased as TWD decreased, which was attributed to non-precipitation climatic conditions favoring turfgrass canopy wetness. This research will improve turfgrass management practices and research designed to minimize human 2,4-D exposure. PMID:26863005

  20. Quantitative evaluation study of four-dimensional gated cardiac SPECT reconstruction

    PubMed Central

    Jin, Mingwu; Yang, Yongyi; Niu, Xiaofeng; Marin, Thibault; Brankov, Jovan G.; Feng, Bing; Pretorius, P. Hendrik; King, Michael A.; Wernick, Miles N.

    2013-01-01

    In practice gated cardiac SPECT images suffer from a number of degrading factors, including distance-dependent blur, attenuation, scatter, and increased noise due to gating. Recently we proposed a motion-compensated approach for four-dimensional (4D) reconstruction for gated cardiac SPECT, and demonstrated that use of motion-compensated temporal smoothing could be effective for suppressing the increased noise due to lowered counts in individual gates. In this work we further develop this motion-compensated 4D approach by also taking into account attenuation and scatter in the reconstruction process, which are two major degrading factors in SPECT data. In our experiments we conducted a thorough quantitative evaluation of the proposed 4D method using Monte Carlo simulated SPECT imaging based on the 4D NURBS-based cardiac-torso (NCAT) phantom. In particular we evaluated the accuracy of the reconstructed left ventricular myocardium using a number of quantitative measures including regional bias-variance analyses and wall intensity uniformity. The quantitative results demonstrate that use of motion-compensated 4D reconstruction can improve the accuracy of the reconstructed myocardium, which in turn can improve the detectability of perfusion defects. Moreover, our results reveal that while traditional spatial smoothing could be beneficial, its merit would become diminished with the use of motion-compensated temporal regularization. As a preliminary demonstration, we also tested our 4D approach on patient data. The reconstructed images from both simulated and patient data demonstrated that our 4D method can improve the definition of the LV wall. PMID:19724094

  1. Digit ratio (2D:4D), aggression, and testosterone in men exposed to an aggressive video stimulus.

    PubMed

    Kilduff, Liam P; Hopp, Renato N; Cook, Christian J; Crewther, Blair T; Manning, John T

    2013-01-01

    The relative lengths of the 2(nd) and 4(th) digits (2D:4D) is a negative biomarker for prenatal testosterone, and low 2D:4D may be associated with aggression. However, the evidence for a 2D:4D-aggression association is mixed. Here we test the hypothesis that 2D:4D is robustly linked to aggression in "challenge" situations in which testosterone is increased. Participants were exposed to an aggressive video and a control video. Aggression was measured after each video and salivary free testosterone levels before and after each video. Compared to the control video, the aggressive video was associated with raised aggression responses and a marginally significant increase in testosterone. Left 2D:4D was negatively correlated with aggression after the aggressive video and the strength of the correlation was higher in those participants who showed the greatest increases in testosterone. Left 2D:4D was also negatively correlated to the difference between aggression scores in the aggressive and control conditions. The control video did not influence testosterone concentrations and there were no associations between 2D:4D and aggression. We conclude that 2D:4D moderates the impact of an aggressive stimulus on aggression, such that an increase in testosterone resulting from a "challenge" is associated with a negative correlation between 2D:4D and aggression.

  2. Construction of 4D high-definition cortical surface atlases of infants: Methods and applications.

    PubMed

    Li, Gang; Wang, Li; Shi, Feng; Gilmore, John H; Lin, Weili; Shen, Dinggang

    2015-10-01

    In neuroimaging, cortical surface atlases play a fundamental role for spatial normalization, analysis, visualization, and comparison of results across individuals and different studies. However, existing cortical surface atlases created for adults are not suitable for infant brains during the first two postnatal years, which is the most dynamic period of postnatal structural and functional development of the highly-folded cerebral cortex. Therefore, spatiotemporal cortical surface atlases for infant brains are highly desired yet still lacking for accurate mapping of early dynamic brain development. To bridge this significant gap, leveraging our infant-dedicated computational pipeline for cortical surface-based analysis and the unique longitudinal infant MRI dataset acquired in our research center, in this paper, we construct the first spatiotemporal (4D) high-definition cortical surface atlases for the dynamic developing infant cortical structures at seven time points, including 1, 3, 6, 9, 12, 18, and 24 months of age, based on 202 serial MRI scans from 35 healthy infants. For this purpose, we develop a novel method to ensure the longitudinal consistency and unbiasedness to any specific subject and age in our 4D infant cortical surface atlases. Specifically, we first compute the within-subject mean cortical folding by unbiased groupwise registration of longitudinal cortical surfaces of each infant. Then we establish longitudinally-consistent and unbiased inter-subject cortical correspondences by groupwise registration of the geometric features of within-subject mean cortical folding across all infants. Our 4D surface atlases capture both longitudinally-consistent dynamic mean shape changes and the individual variability of cortical folding during early brain development. Experimental results on two independent infant MRI datasets show that using our 4D infant cortical surface atlases as templates leads to significantly improved accuracy for spatial normalization

  3. Optimizing 4D cone beam computed tomography acquisition by varying the gantry velocity and projection time interval.

    PubMed

    O'Brien, Ricky T; Cooper, Benjamin J; Keall, Paul J

    2013-03-21

    Four dimensional cone beam computed tomography (4DCBCT) is an emerging clinical image guidance strategy for tumour sites affected by respiratory motion. In current generation 4DCBCT techniques, both the gantry rotation speed and imaging frequency are constant and independent of the patient's breathing which can lead to projection clustering. We present a mixed integer quadratic programming (MIQP) model for respiratory motion guided-4DCBCT (RMG-4DCBCT) which regulates the gantry velocity and projection time interval, in response to the patient's respiratory signal, so that a full set of evenly spaced projections can be taken in a number of phase, or displacement, bins during the respiratory cycle. In each respiratory bin, an image can be reconstructed from the projections to give a 4D view of the patient's anatomy so that the motion of the lungs, and tumour, can be observed during the breathing cycle. A solution to the full MIQP model in a practical amount of time, 10 s, is not possible with the leading commercial MIQP solvers, so a heuristic method is presented. Using parameter settings typically used on current generation 4DCBCT systems (4 min image acquisition, 1200 projections, 10 respiratory bins) and a sinusoidal breathing trace with a 4 s period, we show that the root mean square (RMS) of the angular separation between projections with displacement binning is 2.7° using existing constant gantry speed systems and 0.6° using RMG-4DCBCT. For phase based binning the RMS is 2.7° using constant gantry speed systems and 2.5° using RMG-4DCBCT. The optimization algorithm presented is a critical step on the path to developing a system for RMG-4DCBCT.

  4. Biological and molecular responses of Chironomus riparius (Diptera, Chironomidae) to herbicide 2,4-D (2,4-dichlorophenoxyacetic acid).

    PubMed

    Park, Kiyun; Park, Jungan; Kim, Jongkyu; Kwak, Inn-Sil

    2010-05-01

    2,4-Dichlorophenoxyacetic acid (2,4-D) is an agricultural contaminant found in rural ground water. It remains to be determined whether neither 2,4-D poses environmental risks, nor is the mechanism of toxicity known at the molecular level. To evaluate the potential ecological risk of 2,4-D, we assessed the biological parameters including the survival rate, adult sex ratio of emerged adults, and mouthpart deformities in Chironomus riparius after long-term exposure to 2,4-D. The larvae were treated with 0.1, 1 or, 10microgL(-1) of 2,4-D for short- and long-term exposure periods. The sex ratio was changed in C. riparius exposed to only 10microgL(-1) of 2,4-D, whereas mouthpart deformities were observed as significantly higher in C. riparius exposed to 0.1microgL(-1) of 2,4-D. Survival rates were not significantly affected by 2,4-D. Furthermore, we evaluated the molecular and biochemical responses of biomarker genes such as gene expression of heat shock proteins (HSPs), ferritins and glutathione S-transferases (GSTs) in C. riparius exposed to 2,4-D for 24h. The expressions of HSP70, HSP40, HSP90 and GST levels in C. riparius were significantly increased after exposure to a 10microgL(-1) concentration of 2,4-D, whereas ferritin heavy and light chain gene expressions were significantly increased at all concentrations of 2,4-D exposure. Finally, these results may provide an important contribution to our understanding of the toxicology of 2,4-D herbicide in C. riparius. Moreover, the 2,4-D-mediated gene expressions may be generated by 2,4-D is the causative effects on most probable cause of the observed alterations. These biological, molecular and morphological parameters and the measured parameters can be used to monitor 2,4-D toxicity in an aquatic environment.

  5. A novel image reconstruction methodology based on inverse Monte Carlo analysis for positron emission tomography

    NASA Astrophysics Data System (ADS)

    Kudrolli, Haris A.

    2001-04-01

    A three dimensional (3D) reconstruction procedure for Positron Emission Tomography (PET) based on inverse Monte Carlo analysis is presented. PET is a medical imaging modality which employs a positron emitting radio-tracer to give functional images of an organ's metabolic activity. This makes PET an invaluable tool in the detection of cancer and for in-vivo biochemical measurements. There are a number of analytical and iterative algorithms for image reconstruction of PET data. Analytical algorithms are computationally fast, but the assumptions intrinsic in the line integral model limit their accuracy. Iterative algorithms can apply accurate models for reconstruction and give improvements in image quality, but at an increased computational cost. These algorithms require the explicit calculation of the system response matrix, which may not be easy to calculate. This matrix gives the probability that a photon emitted from a certain source element will be detected in a particular detector line of response. The ``Three Dimensional Stochastic Sampling'' (SS3D) procedure implements iterative algorithms in a manner that does not require the explicit calculation of the system response matrix. It uses Monte Carlo techniques to simulate the process of photon emission from a source distribution and interaction with the detector. This technique has the advantage of being able to model complex detector systems and also take into account the physics of gamma ray interaction within the source and detector systems, which leads to an accurate image estimate. A series of simulation studies was conducted to validate the method using the Maximum Likelihood - Expectation Maximization (ML-EM) algorithm. The accuracy of the reconstructed images was improved by using an algorithm that required a priori knowledge of the source distribution. Means to reduce the computational time for reconstruction were explored by using parallel processors and algorithms that had faster convergence rates

  6. 78 FR 11766 - Endangered and Threatened Wildlife and Plants; Special Rule for the Polar Bear Under Section 4(d...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    ... (Court) found that, although the final 4(d) special rule published December 16, 2008 (73 FR 76249) for... bear (Ursus maritimus) as a threatened species under the ESA (73 FR 28212). At the same time, the... prohibited certain acts covered in section 9(a)(1) of the ESA (73 FR 28306); ] this interim 4(d) special...

  7. QUANTIFICATION OF 2,4-D ON SOLID-PHASE EXPOSURE SAMPLING MEDIA BY LC/MS/MS

    EPA Science Inventory

    Three types of solid phase chemical exposure sampling media: cellulose, polyurethane foam (PUF) and XAD-2, were analyzed for 2,4-D and the amine salts of 2,4-D. Individual samples were extracted into acidified methanol and the extracts were analyzed via LC/MS/MS using electrospra...

  8. Field testing Northern U.S. adapted 2,4-D resistant red clover (Trifolium pratense L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    2,4-Dichlorophenoxyacetic acid (2,4-D) resistant red clover (Trifolium pratense L.) varieties would offer producers more weed control options, particularly in mixed grass/red clover pastures. In the 1980s, work was initiated in Florida to select for 2,4-D tolerant red clover (Taylor, 1989). This Flo...

  9. The 2D:4D ratio of the hand and schizotypal personality traits in schizophrenia patients and healthy control persons.

    PubMed

    Zhu, Yi-Kang; Li, Chun-Bo; Jin, Jin; Wang, Ji-Jun; Lachmann, Bernd; Sariyska, Rayna; Montag, Christian

    2014-06-01

    Prenatal estrogen/testosterone exposure is known to be involved in early brain development. In this context, the ratio of the index finger to ring finger length (2D:4D) has been put forward as an indicator of the intrauterine sex hormonal level. A previous study by Collinson et al. (2010) examined 2D:4D ratios in Asian patients with schizophrenia and found an increased 2D:4D pattern in male patients compared to male healthy controls. In the current study, we tried to replicate the result of this study on the 2D:4D ratio in schizophrenia patients and controls in a Chinese sample. Moreover, we investigated the link between 2D:4D ratios and schizotypal personality traits in the participants of the study. No significant difference between cases and controls in 2D:4D ratios for both hands could be observed. However, a positive association between right 2D:4D ratio and schizotypal personality traits was found in healthy controls (both in the male and female subsamples) suggesting that a high 2D:4D ratio could represent a vulnerability factor for schizophrenia in healthy males and females. Same results were observed for the digit ratio of the left hand and the SPQ in the healthy total and healthy female subsample. Therefore, the inclusion of personality measures to study the link between the digit ratio and schizophrenia mig