scholarly journals Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

2016 ◽  
Vol 796 ◽  
pp. 558-587 ◽  
Author(s):  
Ronny Pini ◽  
Nicholas T. Vandehey ◽  
Jennifer Druhan ◽  
James P. O’Neil ◽  
Sally M. Benson
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Tracer Tests ◽  
Spatial Arrangement ◽  
Small Scale ◽  
Local Dispersion ◽  
Advection Dispersion ◽  
Driving Mechanisms ◽  
Positron Emission ◽  
Longitudinal Dispersivity

We report results of an experimental investigation into the effects of small-scale (mm–cm) heterogeneities on solute spreading and mixing in a Berea sandstone core. Pulse-tracer tests have been carried out in the Péclet number regime $Pe=6{-}40$ and are supplemented by a unique combination of two imaging techniques. X-ray computed tomography (CT) is used to quantify subcore-scale heterogeneities in terms of permeability contrasts at a spatial resolution of approximately $10~\text{mm}^{3}$, while [11C] positron emission tomography (PET) is applied to image the spatial and temporal evolution of the full tracer plume non-invasively. To account for both advective spreading and local (Fickian) mixing as driving mechanisms for solute transport, a streamtube model is applied that is based on the one-dimensional advection–dispersion equation. We refer to our modelling approach as semideterministic, because the spatial arrangement of the streamtubes and the corresponding solute travel times are known from the measured rock’s permeability map, which required only small adjustments to match the measured tracer breakthrough curve. The model reproduces the three-dimensional PET measurements accurately by capturing the larger-scale tracer plume deformation as well as subcore-scale mixing, while confirming negligible transverse dispersion over the scale of the experiment. We suggest that the obtained longitudinal dispersivity ($0.10\pm 0.02$  cm) is rock rather than sample specific, because of the ability of the model to decouple subcore-scale permeability heterogeneity effects from those of local dispersion. As such, the approach presented here proves to be very valuable, if not necessary, in the context of reservoir core analyses, because rock samples can rarely be regarded as ‘uniformly heterogeneous’.

scholarly journals Measurement of three-dimensional displacement field in piled embankments using synchrotron X-ray tomography

2019 ◽  
Vol 56 (6) ◽  
pp. 885-892 ◽  
Author(s):  
Louis King ◽  
Abdelmalek Bouazza ◽  
Anton Maksimenko ◽  
Will P. Gates ◽  
Stephen Dubsky
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Physical Models ◽  
Scale Model ◽  
Small Scale ◽  
Full Field ◽  
X Ray ◽  
Wide Range ◽  
Piled Embankments

The measurement of displacement fields by nondestructive imaging techniques opens up the potential to study the pre-failure mechanisms of a wide range of geotechnical problems within physical models. With the advancement of imaging technologies, it has become possible to achieve high-resolution three-dimensional computed tomography volumes of relatively large samples, which may have previously resulted in excessively long scan times or significant imaging artefacts. Imaging of small-scale model piled embankments (142 mm diameter) comprising sand was undertaken using the imaging and medical beamline at the Australian Synchrotron. The monochromatic X-ray beam produced high-resolution reconstructed volumes with a fine texture due to the size and mineralogy of the sand grains as well as the phase contrast enhancement achieved by the monochromatic X-ray beam. The reconstructed volumes were well suited to the application of digital volume correlation, which utilizes cross-correlation techniques to estimate three-dimensional full-field displacement vectors. The output provides insight into the strain localizations that develop within piled embankments and an example of how advanced imaging techniques can be utilized to study the kinematics of physical models.

scholarly journals Neuroanatomical phenotyping of the mouse brain with three-dimensional autofluorescence imaging

2012 ◽  
Vol 44 (15) ◽  
pp. 778-785 ◽  
Author(s):  
Jacqueline A. Gleave ◽  
Michael D. Wong ◽  
Jun Dazai ◽  
Maliha Altaf ◽  
R. Mark Henkelman ◽  
...  
Keyword(s):  
Optical Imaging ◽  
Mouse Brain ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Brain Structures ◽  
Small Scale ◽  
Specimen Preparation ◽  
Normal Brain ◽  
Autofluorescence Imaging ◽  
The Brain

The structural organization of the brain is important for normal brain function and is critical to understand in order to evaluate changes that occur during disease processes. Three-dimensional (3D) imaging of the mouse brain is necessary to appreciate the spatial context of structures within the brain. In addition, the small scale of many brain structures necessitates resolution at the ∼10 μm scale. 3D optical imaging techniques, such as optical projection tomography (OPT), have the ability to image intact large specimens (1 cm3) with ∼5 μm resolution. In this work we assessed the potential of autofluorescence optical imaging methods, and specifically OPT, for phenotyping the mouse brain. We found that both specimen size and fixation methods affected the quality of the OPT image. Based on these findings we developed a specimen preparation method to improve the images. Using this method we assessed the potential of optical imaging for phenotyping. Phenotypic differences between wild-type male and female mice were quantified using computer-automated methods. We found that optical imaging of the endogenous autofluorescence in the mouse brain allows for 3D characterization of neuroanatomy and detailed analysis of brain phenotypes. This will be a powerful tool for understanding mouse models of disease and development and is a technology that fits easily within the workflow of biology and neuroscience labs.

scholarly journals The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Gisele C. Pereira ◽  
Melanie Traughber ◽  
Raymond F. Muzic
Keyword(s):  
Treatment Planning ◽  
Planning Process ◽  
Imaging Modality ◽  
Imaging Techniques ◽  
Treatment Options ◽  
Three Dimensional ◽  
Dose Calculation ◽  
Positron Emission ◽  
Tissue Contrast ◽  
Anatomical Information

The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning. Despite some disadvantages, CT remains the only three-dimensional imaging modality used for dose calculation. Newer image modalities, such as magnetic resonance (MR) imaging and positron emission tomography (PET), are also used secondarily in the treatment-planning process. MR, with its better tissue contrast and resolution than those of CT, improves tumor definition compared with CT planning alone. PET also provides metabolic information to supplement the CT and MR anatomical information. With emerging molecular imaging techniques, the ability to visualize and characterize tumors with regard to their metabolic profile, active pathways, and genetic markers, both across different tumors and within individual, heterogeneous tumors, will inform clinicians regarding the treatment options most likely to benefit a patient and to detect at the earliest time possible if and where a chosen therapy is working. In the post-human-genome era, multimodality scanners such as PET/CT and PET/MR will provide optimal tumor targeting information.

Editorial Preface

1990 ◽  
Vol 157 (S9) ◽  
pp. 7-9 ◽  
Author(s):  
M. T. Abou-Saleh
Keyword(s):  
Sigmund Freud ◽  
Brain Structure ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Three Dimensional ◽  
Computerised Tomography ◽  
Brain Science ◽  
Positron Emission ◽  
Neuroimaging Techniques

The introduction of neuroimaging techniques for the study of brain structure and function has revolutionised the endeavour to elucidate the pathology of psychiatric disorder, the Holy Grail in psychiatry (Krishnan, 1990). Emil Kraepelin discovered the two major mental disorders, dementia praecox and manic-depression, and conceived their aetiology in brain pathology. It was Alois Alzheimer, however, his most successful student, who discovered the neuropathology of Alzheimer's disease. Sigmund Freud, who started his inquiries in brain science, lost faith and shifted to the study of the mind. Brain science and mind ‘science’ rapidly became odd bed fellows and parted company. The breakdown in communication fostered a mistrust in both parties, aborting endeavours of reconciliation. The evidence for the neuropathology of the ‘functional’ psychoses has, however, been inconclusive. It was the advent of brain-imaging techniques that rejuvenated brain sciences and modern neurosciences. The introduction of neuroimaging techniques, such as the electroencephalogram (EEG) in the 1920s and the whole-brain blood-flow techniques (Berger, 1929; Kety & Schmidt, 1948), antedated the discovery of psychotropic drugs. Pneumoencephalography was also applied to study brain structure in schizophrenia (Storey, 1966). The true methodological leap, however, was the introduction of computerised methods to construct three-dimensional images from two-dimensional data, enabling the development of computerised tomography (CT), magnetic resonance imaging (MRI), positron-emission tomography (PET) and single-photon emission computerised tomography (SPECT).

scholarly journals Kidney Segmentation in CT Data Using Hybrid Level-Set Method with Ellipsoidal Shape Constraints

2017 ◽  
Vol 24 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Andrzej Skalski ◽  
Katarzyna Heryan ◽  
Jacek Jakubowski ◽  
Tomasz Drewniak
Keyword(s):  
Computed Tomography ◽  
Level Set ◽  
Renal Cancer ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Energy Functional ◽  
Contour Method ◽  
Ellipsoidal Shape ◽  
Kidney Segmentation

Abstract With development of medical diagnostic and imaging techniques the sparing surgeries are facilitated. Renal cancer is one of examples. In order to minimize the amount of healthy kidney removed during the treatment procedure, it is essential to design a system that provides three-dimensional visualization prior to the surgery. The information about location of crucial structures (e.g. kidney, renal ureter and arteries) and their mutual spatial arrangement should be delivered to the operator. The introduction of such a system meets both the requirements and expectations of oncological surgeons. In this paper, we present one of the most important steps towards building such a system: a new approach to kidney segmentation from Computed Tomography data. The segmentation is based on the Active Contour Method using the Level Set (LS) framework. During the segmentation process the energy functional describing an image is the subject to minimize. The functional proposed in this paper consists of four terms. In contrast to the original approach containing solely the region and boundary terms, the ellipsoidal shape constraint was also introduced. This additional limitation imposed on evolution of the function prevents from leakage to undesired regions. The proposed methodology was tested on 10 Computed Tomography scans from patients diagnosed with renal cancer. The database contained the results of studies performed in several medical centers and on different devices. The average effectiveness of the proposed solution regarding the Dice Coefficient and average Hausdorff distance was equal to 0.862 and 2.37 mm, respectively. Both the qualitative and quantitative evaluations confirm effectiveness of the proposed solution.

scholarly journals Three-dimensional radar imaging of atmospheric layer and turbulence structures using multiple receivers and multiple frequencies

2014 ◽  
Vol 32 (8) ◽  
pp. 899-909 ◽  
Author(s):  
J.-S. Chen ◽  
J. Furumoto ◽  
M. Yamamoto
Keyword(s):  
Layer Structure ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Radar Imaging ◽  
Horizontal Wind ◽  
Small Scale ◽  
Turbulent Structures ◽  
Turbulence Structures ◽  
Air Turbulence ◽  
Finite Resolution

Abstract. The pulsed, beamwidth-limited atmospheric radar suffers from a finite resolution volume, making it difficult to resolve the small-scale irregularity structure of refractive index (or clear-air turbulence) in the scattering region. Multi-receiver and multi-frequency imaging techniques were thus proposed to improve the spatial resolution of the measurements in the finite resolution volume. The middle and upper atmosphere radar (MUR; 34.85° N, 136.10° N) possesses the capabilities of 5 frequencies, ranging from 46 MHz to 47 MHz, and up to 25 receivers to carry out the imaging techniques. In this paper, we exhibit the three-dimensional (3-D) radar imaging utilizing five frequencies and 19 receivers of the MUR. The Capon method was employed for the process of imaging, and examinations of a wavy layer and turbulent structures were made, in which the spatial weighting effect on the imaging were mitigated beforehand. Information such as echo center and structure morphology in the resolution volume was then extracted. For example, the location distribution of echo centers could imply the traveling orientation of the wavy layer, which was correspondent with horizontal wind direction. Such information of wavy layer structure was more difficult to disclose without removal of the spatial weighting effect. This paper demonstrates an advanced application of 3-D radar imaging to some practical atmospheric phenomena.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

1975 ◽  
Vol 33 ◽  
pp. 286-287
Author(s):  
Jerome J. Paulin
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Posterior Pole ◽  
Dimensional Structure ◽  
Stereo Imaging ◽  
Thin Sections ◽  
Anatomical Features ◽  
The Past ◽  
Cellular Components ◽  
Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

Image formation analysis of thick biological specimens using three-dimensional power-spectra of through focus series

1994 ◽  
Vol 52 ◽  
pp. 124-125
Author(s):  
Karen F. Han
Keyword(s):  
Inelastic Scattering ◽  
Imaging Techniques ◽  
Mass Density ◽  
Relative Proportion ◽  
Three Dimensional ◽  
Power Spectra ◽  
Image Formation ◽  
Energy Filtering ◽  
Ewald Sphere ◽  
Nonlinear Imaging

The primary focus in our laboratory is the study of higher order chromatin structure using three dimensional electron microscope tomography. Three dimensional tomography involves the deconstruction of an object by combining multiple projection views of the object at different tilt angles, image intensities are not always accurate representations of the projected object mass density, due to the effects of electron-specimen interactions and microscope lens aberrations. Therefore, an understanding of the mechanism of image formation is important for interpreting the images. The image formation for thick biological specimens has been analyzed by using both energy filtering and Ewald sphere constructions. Surprisingly, there is a significant amount of coherent transfer for our thick specimens. The relative amount of coherent transfer is correlated with the relative proportion of elastically scattered electrons using electron energy loss spectoscopy and imaging techniques.Electron-specimen interactions include single and multiple, elastic and inelastic scattering. Multiple and inelastic scattering events give rise to nonlinear imaging effects which complicates the interpretation of collected images.

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